EA024494B1 - Process for separation of a gas stream - Google Patents

Abstract

A process and an apparatus are disclosed for a compact processing assembly to recover C(or C) components and heavier hydrocarbon components from a hydrocarbon gas stream. The gas stream is cooled and divided into first and second streams. The first stream is further cooled, expanded to lower pressure, and supplied as a feed between first and second absorbing means. The second stream is expanded to lower pressure and supplied as bottom feed to the second absorbing means. A distillation vapor stream from the first absorbing means is heated, compressed to higher pressure, and divided into a volatile residue gas fraction and a compressed recycle stream. The compressed recycle stream is cooled, expanded to lower pressure, and supplied as top feed to the first absorbing means. A distillation liquid stream from the bottom second absorbing means is heated in a heat and mass transfer means to strip out its volatile components.

Description

The present invention mainly contemplates a method for recovering ethylene, ethane, propylene, propane and heavier hydrocarbons from such gas streams. A gas suitable for processing in accordance with the present invention has the following typical composition, expressed in molar percent: 90.3% methane; 4.0% ethane and other C ₂ components; 1.7% propane and other C ₃ components; 0.3% isobutane; 0.5% standard butane; and 0.8% of pentanes and heavier hydrocarbons, the balance is maintained by nitrogen and carbon dioxide. The presence of sulfur-containing gases is also sometimes noted.

Historically, cyclical changes in prices for both natural gas and its gas condensate (LNO) components at times determine a decrease in the growth of ethane, ethylene, propane, propylene and heavier components as liquid products. As a result, a need has arisen for technological methods that could provide more efficient extraction of these products from raw gas, while the extraction efficiency should be accompanied by a reduction in investment. Known methods for separating these materials include methods that are based on cooling and liquefying a gas, absorption of oil, and absorption of refrigerated oil. In addition, cryogenic methods have gained popularity due to the availability of cost-effective equipment that generates electricity by directing gas to the expander and simultaneously removing heat from the processed gas. Depending on the pressure of the gas supply source, the saturation of the gas (ethane, ethylene and heavier hydrocarbon components), as well as on the desired end product, any of these methods or a combination of them can be used.

Today, for the processing of natural gas condensate, preference is mainly given to the cryogenic expansion method, since it combines maximum simplicity, ease of commissioning, operational flexibility, high efficiency, safety and high reliability. U.S. Patents 3,292,380; 4,061,481; 4,140,504; 4,157,904; 4,171,964; 4,185,978; 4,251,249; 4,278,457; 4,519,824; 4,617,039; 4,687,499; 4,689,063; 4,690,702; 4,854,955; 4,869,740; 4,889,545; 5,275,005; 5,555,748; 5,566,554; 5,568,737; 5771712; 5,799,507; 5,881,569; 5,890,378; 5,983,664; 6182469; 6,578,379; 6,712,880; 6,915,662; 7191617; 7,219,513; in the replacement US patent No. 33408; as well as in simultaneously pending applications under numbers 11 / 430,412; 11 / 839.693; 11 / 971,491; 12 / 206,230; 12 / 689.616; 12 / 717,394; 12 / 750,862; 12 / 772,472; 12 / 781,259; 12 / 868,993; 12 / 869,007; 12 / 869,139; 12 / 979,563; 13 / 048,315; 13 / 051,682 describes the corresponding methods (although the description of the present invention in some cases uses processing modes other than those described in these US patents).

In a typical cryogenic expansion process, the pressurized gas is cooled by heat exchange with other process streams and / or with external cooling sources, such as a propane compression cooling system. As the gas cools in one or more separators, condensation and condensate collection takes place, since condensate under high pressure contains a certain amount of necessary C ₂ + components. Depending on the saturation of the gas and the amount of condensate obtained, the condensate under high pressure can be expanded at lower pressure and fractionated. The evaporation that occurs during expansion of the condensate results in further cooling of the working stream. Under certain conditions, it may be necessary to pre-cool the condensate under high pressure before expanding, in order to further reduce the temperature as a result of expansion. The expanded working stream, consisting of a mixture of condensate and vapor, is fractionated in a distillation column (demethanizer or deethanizer). Inside the column, the cooled stream is subjected to rectification in order to separate residual methane, nitrogen and other volatile gases in the form of helium vapors from the required C ₂ components, C ₃ components and heavier hydrocarbon components, which are discharged from the bottom of the column as a liquid bottoms product; or for the purpose of separating residual methane, C ₂ components, nitrogen and other volatile gases in the form of helium vapors from the necessary C ₃ components and heavier hydrocarbon components that are discharged from the bottom of the column as a liquid bottoms product.

With incomplete condensation of the feed gas (this usually happens), the vapors remaining after incomplete condensation can be divided into two streams. One part of the vapor is directed through an expander or expansion valve into a vessel with a lower pressure, where additional condensation of the liquid occurs as a result of further cooling of the working stream. The pressure after expansion is actually equal to the pressure under which the distillation column operates. The vapor and liquid phases obtained as a result of expansion are fed into the column as raw materials.

The remaining vapors are cooled to complete condensation by heat exchange with other process streams, for example, with the top product of a cold distillation column. Before cooling

- 1,024,494, these pairs can be mixed with part of the condensate at high pressure or with its entire volume. The resulting cooled stream is then expanded in a suitable device, for example in an expansion valve, of the working pressure of the demethanizer. In the expansion method, a part of the condensate evaporates, as a result of which the main working stream is cooled. The evaporation-throttled stream is then fed to the top of the demethanizer. Typically, the vapor component of the throttled vaporization stream and the helium vapor from the demethanizer are mixed in the upper separator section of the distillation column and form residual synthetic methane gas. Alternatively, it is possible to supply a cooled expanded working stream to the separator, for its separation into vapor and liquid streams. The vapor stream is mixed with the helmet pairs of the column, and condensate is supplied to the top of the column as liquid feed.

Under ideal conditions, with this separation method, the residual gas leaving the unit will contain almost all the methane that was in the feed gas, while the heavier hydrocarbons and the lower distillation fraction leaving the demethanizer will not contain methane or more volatile components. In practice, however, it is not possible to create ideal conditions, since a conventional demethanizer mainly works as a stripping column. Consequently, the methane product obtained at the outlet of the technical process usually consists of vapors from the upper rectification zone of the column, as well as vapors that have not passed rectification. Significant losses of components C ₂ , C ₃ and C ₄ + occur because the liquid feed, which is fed to the top of the column, contains a sufficient amount of these and heavier hydrocarbon components, resulting in a number of C ₂ components, C ₃ components, C ₄ components and heavier hydrocarbon components is almost equal to their amount in the vapor, which is allocated in the upper zone of rectification of the demethanizer. The loss of these necessary components can be significantly reduced if the vapors rising from the rectification zone come into contact with a sufficient amount of condensate (from the reflux stream) capable of absorbing components C2, C3, C4 and heavier hydrocarbon components from the vapor.

In recent years, hydrocarbon separation methods have been preferred, where an upper absorption section is provided in the installation for additional vapor distillation. The source of the return stream for the upper distillation section is usually a recycled stream of residual gas supplied under pressure. The recycled residual gas stream is usually cooled to significant condensation due to heat exchange with other process streams, such as cold overhead distillation column. The resulting cooled stream is then expanded in a suitable device, for example in an expansion valve, to the operating pressure of the demethanizer. In the expansion method, part of the condensate is usually evaporated, as a result of which the main working stream is cooled. The evaporation-throttled stream is then fed to the top of the demethanizer. Typically, the vapor component of the vapor-throttled stream and the helium vapor from the demethanizer are mixed in the upper separator section of the distillation column and form residual methane gas. Alternatively, it is possible to supply a cooled expanded working stream to a separator, where it is divided into steam and condensate streams, after which the steam is mixed with the overhead of the column, and condensate is supplied to its upper part as a raw material. Typical schemes of this method are described in US patents numbered 4889545; 5,568,737; 5881569, as well as in simultaneously pending applications under the numbers 11 / 430,412; 11 / 971,491; 12 / 717,394; as well as a report by Moury, E. Ross, Effective Recovery of Liquids from Natural Gas Using a High Pressure Absorber, which was presented at the 81st annual conference of the Gas Processors Association in Dallas, Texas, March 11–13, 2002.

The present invention employs the latest means of implementing the various steps of the above method, which improves overall efficiency and reduces the number of required pieces of equipment. This is achieved by combining in a single installation several units of equipment that were previously independent, while reducing the area needed to accommodate the technological installation, as well as reducing capital costs. Unexpectedly, the applicants found that a more compact scheme also contributes to a significant reduction in power consumption necessary to achieve a given level of processing, which generally increases technological efficiency and reduces the cost of operation of the installation. In addition, a more compact layout scheme eliminates a significant part of the pipelines that connected individual pieces of equipment in installations of a traditional design, which further reduces capital costs and allows you to remove the corresponding flange connections for connecting pipelines from the structure. Since hydrocarbon leakages (which are volatile organic compounds (VOCs) involved in the formation of gases causing the greenhouse effect, as well as creating the prerequisites for the formation of holes in the ozone layer) are possible on flanged pipe joints, the rejection of these flanges in the design reduces the possibility pollutant emissions into the atmosphere.

In accordance with the present invention, it was found that it is possible to achieve a C ₂ emission level _of more than 95%. Similarly, in cases where the separation of C ₂ components is undesirable, it is possible to isolate C ₃ components in excess of 95%. In addition, the present invention

- 2 024494 allows for 100% separation of methane (or C ₂ components) and components lighter than C ₂ components (or C ₃ components), as well as heavier components, at a lower energy intensity compared to the prior art, with this level of allocation remains unchanged. The present invention (despite the fact that it is implemented at lower pressures and higher temperatures) is particularly effective in the processing of feed gases in the pressure range from 400 to 1500 psi abs. [2,758-10,342 kPa (a)] or higher, under conditions where the temperature of the top product of the gas condensate recovery column is in the range of -50 ° P [-46 ° C] or lower.

To facilitate understanding of the essence of the present invention, the following drawings and examples are provided in the description. References to the drawings:

FIG. 1 is a block diagram of a natural gas processing plant made in accordance with the prior art according to US Pat. No. 5,568,737;

FIG. 2 is a block diagram of a natural gas processing plant in accordance with the present invention;

FIG. 3-17 are flowcharts illustrating alternative methods of using the present invention to process a natural gas stream.

In the following description of the above figures, tables with summary data on gas consumption calculated for typical processing modes are given. In the tables given in this document, the gas flow rate (mol per hour) is rounded to the nearest whole number for readability. The total flow rates shown in the tables take into account all non-hydrocarbon components, and therefore, are greater than the values of the total flow rate of hydrocarbon components. The temperature values shown in the tables are approximate, rounded to the degree. It should also be noted that the calculations of technological schemes in order to compare the effectiveness of the technical methods shown in the figures are based on the assumption that there is no heat leakage between the environment and the method (in both directions). The quality of the insulating materials on the market allows us to consider this assumption reasonable, despite the fact that specialists with the appropriate level of technical training usually use it in their calculations.

For ease of perception, technological parameters are indicated both in traditional British units of measurement, and in units of measurement of the International System of Units (SI). The molar gas flow rates indicated in the tables can be expressed either as pound mol per hour, or as kilogram mol per hour. The energy consumed, expressed in horsepower (hp) and / or in thousands of British thermal units per hour (MBTU / h), corresponds to the indicated molar flow rate, expressed in pound moles per hour. The energy consumed, expressed in kilowatts (kW), corresponds to the indicated molar flow, expressed in kilogram moles per hour.

Description of the prior art

In FIG. 1 is a flowchart of a process method that shows a device for a processing plant designed to separate C ₂ + components from natural gas, implemented on the basis of well-known technical solutions, in accordance with US Patent No. 5568737. According to this method modeling scheme, the incoming gas enters installation at a temperature of 110 ° P [43 ° C] and a pressure of 915 psi abs. [6.307 kPa (a)] as stream 31. If the incoming gas contains sulfur compounds in a concentration that violates the requirements for the composition of the working stream, they are removed from the incoming gas using an appropriate pre-treatment unit (not shown in the diagram). In addition, the feed stream is usually subjected to dehydration in order to prevent the formation of hydrate (ice) in cryogenic treatment modes. A solid adsorbent is usually used for these purposes.

The feed stream 31 is divided into two streams 32 and 33. The stream 32 is cooled to a temperature of -26 ° P [-32 ° C] in the heat exchanger 10 due to heat exchange with a cold stream of stripping steam (41a); stream 33 is cooled to a temperature of -32 ° P [-25 ° C] in the heat exchanger 11 due to heat exchange with liquid condensate of a demethanizer reboiler having a temperature of 41 ° P [5 ° C] (stream 43) and with a side liquid condensate of a reboiler a temperature of -49 ° P [-45 ° C] (stream 42). Streams 32a and 33a recombine and form a stream 31a, which enters the separator 12 at a temperature of -28 ° P [-33 ° C] and a pressure of 893 psi abs. [6155 kPa (a)], where the vapor (stream 34) is separated from the liquid condensate (stream 35).

The steam (stream 34) from the separator 12 is divided into two streams - stream 36 and 39. Stream 36, containing about 27% of the total volume of vapor, is mixed with the concentrate in the separator (stream 35), and the resulting stream 38 is passed through a heat exchanger 13, where the selection heat is produced due to interaction with the cold stripping steam stream 41, where the working stream is cooled until it is completely condensed. The resulting condensed stream 38a at a temperature of -139 ° P [-95 ° C], then undergoes rapid evaporation through expansion valve 14 to a working pressure (approximately 396 psi abs. [2730 kPa (a)]) of distillation column 18. In the expansion method, part of the stream is vaporized, as a result of which the main work stream is cooled. In the process method that is illustrated in FIG. 1, the expanded stream 38b after the expansion valve 14 reaches a temperature of -140 ° P [-95 ° C] and is supplied to the distillation column 18 at the first midpoint of the column feed.

- 3,024,494

The remaining 73% of the volume of steam from the separator 12 (stream 39) is supplied to the working expander 15, where the energy of this part of the raw material, which is under high pressure, is converted into mechanical energy. In the expander 15, the vapor undergoes isentropic expansion to the working pressure of the column, while the expanded stream 39a is cooled to a temperature of approximately −95 ° P [−71 ° C]. Typical expanders on the market make it possible to isolate about 80-85% of technological raw materials, theoretically available with perfect isentropic expansion. The energy released is often used to drive a centrifugal compressor (such as element 16), which, for example, can be used to re-compress the heated residual gas (stream 41b). The partially condensed expanded stream 39a is then fed as feed to distillation column 18 at its second midpoint.

The re-compressed and cooled stripping vapor stream 41e is divided into two streams. One part, stream 46, is volatile residual gas. The second part, the recycled stream 45, is fed to the heat exchanger 10, where it is cooled to a temperature of -26 ° P [-32 ° C] due to heat extraction by the cold stream of distillation steam 41a. The cooled recirculated stream 45 is then fed to a heat exchanger 13, where it is cooled to a temperature of -139 ° P [-95 ° C] and is almost completely condensed by heat extraction by a cold stream of stripping steam 41. The condensed stream 45b is then expanded using an appropriate device, for example expansion valve 22, its pressure decreases to the operating pressure of the demethanizer, as a result of which the main working stream is cooled to -147 ° P [-99 ° C]. The expanded stream 45c is then fed to the top of the distillation column 18 as raw material. The vaporous portion of the stream 45c (if present) is mixed with vapors rising from the top of the distillation zone of the column and forms a stream of stripping steam 41, which is discharged from the upper zone of the column.

The demethanizer in column 18 is a conventional distillation column in which several trays are installed at intervals between them, one or more nozzles, or a combination of trays and nozzles. As is often the case with natural gas processing plants, a distillation column may consist of two sections. The upper section 18a is a separator where the top-fed feed containing steam is separated into steam and the liquid component, respectively, and where the steam coming from the bottom rectification or demethanization section 18b is mixed with steam separated from the top-fed feed, resulting in a cold helmet steam demethanizer (stream 41), which is discharged from the top of the column at a temperature of -144 ° P [-98 ° C]. The lower section, the demethanization section 183 contains trays and / or nozzles and provides the necessary contact between the condensate flowing down and the vapor rising up. Reboilers (such as the reboiler and side reboiler described earlier) are also installed in the demethanization section 18b, where the condensate flowing into the bottom of the column is heated and evaporated to form a stripped vapor rising up the column to distill off the liquid product, stream 44, methane and lighter components.

The liquid product stream 44 leaves the bottom of the column at a temperature of 64 ° P [18 ° C], based on typical requirements for a methane / ethane ratio of 0.010: 1, based on the weight of the bottoms product. The helmet steam stream 41 from the demethanizer moves towards the incoming raw gas and recycled stream in the heat exchanger 13, where it is heated to -40 ° P [-40 ° C] (stream 41a), as well as in the heat exchanger 10, where it is heated to 104 ° P [40 ° C] (stream 41b). Then, the stripping steam stream is subjected to secondary compression in two stages. The first stage is the compressor 16, which is driven by the expander 15. The second stage is the compressor 20, which is driven by an additional energy source; here the residual gas (stream 416) is compressed to pressure in the distribution pipeline. After cooling to 110 ° P [43 ° C] in the exhaust cooler 21, stream 41e is separated into residual gas (stream 46) and recycled stream 45, as described previously. Residual gas stream 46 enters the sales pipeline at a pressure of 915 psi. [6307 kPa (a)], which is sufficient to meet the pressure requirements in the pipeline (usually this is the inlet pressure).

Brief data on consumption and energy consumption for the technical method shown in FIG. 1 are given in the following table:

- 4,024,494

Table 1

Information on expense - lb mol / h [kg mol / h] Flow Methane Ethane Propane Bhutans + Total 31 12,398 546 233 229 13,726 32 8,431 371 159 156 9,334 33 3,967 175 74 73 4,392 34 12,195 501 179 77 13,261 35 203 45 54 152 465 36 3,317 136 49 21 3,607 38 3,520 181 103 173 4,072 39 8,878 365 130 56 9,654 41 13,765 thirty 0 0 13,992 45 1,377 3 0 0 1,400 46 12,388 27 0 0 12,592 44 10 519 233 229 1,134

Selected Components *

Ethane 94.99% Propane 99.99% Bhutans + 100.00%

Power.

Residual gas compression: 6.149 hp [10.109 kW].

* (Based on non-rounded flow rates).

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 2 is a flowchart of a technical method in accordance with the present invention. The composition and characteristics of the feed gas taken into account in the method shown in FIG. 2 are similar to those of FIG. 1. Accordingly, the method depicted in FIG. 2 can be compared with the method in FIG. 1, in order to clearly demonstrate the advantages of the present invention.

When modeling the method according to the circuit shown in FIG. 2, the incoming gas enters the installation in the form of stream 31, which is divided into two streams: stream 32 and stream 33 using the first separation device. The first stream, stream 32, enters the heat exchanger at the top of the cooling section of the feedstock 118a, which is located inside the processing unit 118. As a heat exchanger, a fin heat exchanger, a plate heat exchanger, a brazed aluminum heat exchanger, or another type of heat exchanger can be used, including including multi-pass and / or multi-function heat exchangers. The heat exchanger is designed to provide heat exchange between the stream 32 flowing along one course of the heat exchanger and the stripping steam rising from the separator section 118b located inside the processing unit 118, which is heated in the heat exchanger of the lower part of the raw material cooling section 118a. The stream 32 is cooled, while the heating of the stripping steam stream continues, and the stream 32a leaves the heat exchanger at a temperature of −25 ° P [−32 ° C].

The second part of the stream, stream 33, enters the heat and mass transfer device in the demethanization section 118e, which is located inside the processing unit 118. As a heat and mass transfer device, a fin heat exchanger, a plate heat exchanger, a brazed aluminum heat exchanger, or another type of heat exchanger, including multi-pass ones, can be used and / or multifunctional heat exchangers. The heat and mass transfer device is designed to provide heat exchange between the stream 33 flowing along one stroke of the heat and mass transfer device and the stripping condensate stream directed downward from the adsorption section 1184. which is located inside the processing unit 118; thus, the stream 33 is cooled by heating the distillate condensate stream, at the outlet of the heat and mass transfer device, the temperature of the cooled stream 33a is -47 ° P [-44 ° C]. As the flow of the stripping condensate is heated, part of it evaporates and forms stripped vapors, which rise upward while the remaining liquid condensate continues to run downward through the heat and mass transfer device. The heat and mass transfer device provides continuous contact between the stripped vapors and the distillate condensate stream, thereby maintaining mass transfer between the vapor and liquid phases and freeing the liquid product stream 44 from methane and lighter components.

The streams 32a and 33a recombine in a mixing device and form a stream 31a, which enters the separation section 1181, located inside the processing unit 118, at a temperature of -32 ° P [-36 ° C] and a pressure of 900 psi abs. [6203 kPa (a)], where the vapor (stream 34) is separated from the liquid condensate (stream 35). The separation section 118G is separated from the demethanization section 118e by an internal partition or other means so as to enable the two sections to operate inside processing unit 118 at different pressures.

The steam (stream 34) from the separation section 118G is divided into two streams: stream 36 and stream 39 using a second separation device. Stream 36, containing about 27% of the total steam, is mixed with condensate separated in the separator (stream 35, through stream 37) in an additional mixing device, and the resulting stream 38 is sent to a heat exchanger located at the bottom of the cooling section of the feedstock 118a inside processing plant 118. A heat exchanger made of finned tubes, a plate heat exchanger, a brazed aluminum heat exchanger, or another type of heat exchanger, including a heat exchanger, can also be used as a heat exchanger. multi-pass and / or multi-function heat exchangers. The heat exchanger is designed to provide heat exchange between the stream 38 flowing through one stroke of the heat exchanger and the stripping steam rising from the separation section 118b, so that the stream 38 is cooled to complete condensation, while heating the stripping steam.

The resulting condensed stream 38a at a temperature of -138 ° P [-95 ° C], then undergoes rapid evaporation through an expansion valve (first expansion device) 14 to a working pressure (approximately 400 psi [2758 kPa (a)]) sections 118c (absorption devices) and absorption sections 1186 (another absorption device) located inside the processing unit 118. In the expansion method, part of the stream can evaporate, as a result of which the main work stream is cooled. In the process method that is illustrated in FIG. 2, the expanded stream 38b after the expansion valve 14 reaches a temperature of −139 ° P [-95 ° C] and is supplied to the processing unit 118 between the distillation section 118c and the absorption section 1186. The condensate in stream 38b is mixed with condensate from the rectification section 118c, and all the condensate is sent to the absorption section 1186, while the vapor is mixed with the vapors coming from the absorption section 1186, and the resulting vaporous stream is sent to the rectification section 118c.

The remaining 73% of the volume of steam from the separation section 118G (stream 39) is fed to a working expander (second expansion device) 15, where the energy of this part of the feed, which is under high pressure, is converted into mechanical energy. In the expander 15, the vapor undergoes isentropic expansion to the operating pressure of the absorption section 1186, while the expanded stream 39a is cooled to a temperature of about -99 ° P [-73 ° C]. The partially condensed expanded stream 39a is then fed as feed to the bottom of the absorption section 1186 inside the processing unit 118.

The re-compressed and cooled stripping vapor stream 41c is split into two streams using a third separation device. One part, stream 46, is volatile residual gas. The second part, the recycle stream 45, enters the heat exchanger in the cooling section of the raw material 118a, which is located inside the processing unit 118. As a heat exchanger, a fin heat exchanger, a plate heat exchanger, a brazed aluminum heat exchanger, or another type of heat exchanger, can be used, including including multi-pass and / or multi-function heat exchangers. The heat exchanger is designed to provide heat exchange between the stream 45 flowing through one stroke of the heat exchanger and the stripping steam rising from the separation section 118b, so that the stream 45 is cooled to complete condensation, while heating the stripping steam.

The condensed recycle stream 45a leaves the heat exchanger in the cooling section of the feedstock 118a, having a temperature of -138 ° P [-95 ° C] and undergoes rapid evaporation through the expansion valve (third expansion device) 22 to the working pressure of the distillation section 118c located inside the processing unit 118. In the expansion method, part of the stream is vaporized, as a result of which the main work stream is cooled. In the process method that is illustrated in FIG. 2, the expanded stream 45b after the expansion valve 22 reaches a temperature of -146 ° P [-99 ° C] and is supplied to the separation section 118b inside the processing unit 118. The liquid condensate separated here is sent to the distillation section 118c, and the remaining vapors are mixed with vapors rising from the distillation section 118c and form a stream of stripping steam, which is heated in the cooling section 118a.

Absorption devices (first and second absorption devices) are installed in the distillation section 118c and in the absorption section 1186, which consist of several trays with gaps between them, one or more nozzles, or a combination of trays and nozzles. The trays and / or nozzles in the distillation section 624494 of the separation section 118c and in the absorption section 1186 provide the necessary contact between the vapor rising up and the cold condensate flowing down. The liquid component of the expanded stream 39a is mixed with liquid condensate flowing down from the absorption section 1186, and the mixed condensate is received by a condensate collection device located in the processing unit to allow liquid to pass down to the demethanization section 118e. The topped vapors rising from the demethanization section 118e are mixed with the vapors from the expanded stream 39a and then rise to the absorption section 1186, where they come in contact with the cold condensate flowing down to condense and absorb the bulk of the components C ₂ , components C ₃ and heavier components contained in these pairs. Vapors rising from the absorption section 1186 are mixed with the vapors from the expanded stream 38b and then rise to the distillation section 118c, where they come in contact with the cold part of the expanded stream 45b flowing down to condense and absorb the main volume of components C ₂ , C ₃ and more heavy components contained in these vapors. The liquid component of the expanded stream 38b is mixed with liquid condensate flowing down from the distillation section 118c, and the mixed condensate continues to flow into the absorption section 1186.

The distillation condensate flowing down from the heat and mass transfer device in the demethanization section 118e inside the processing unit 118 is freed from methane and lighter components. The obtained liquid product (stream 44) is removed from the lower part of the demethanization section 118e and leaves the processing unit 118 at a temperature of 65 ° P [18 ° C]. The steam stream rising from the separation section 118b is received by a steam collection device located in the processing unit, and then heated in the cooling section of the feedstock 118a, while cooling the streams 32, 38 and 45 as previously described, and the resulting residual gas stream 41 leaves the processing unit installation 118 at a temperature of 105 ° P [40 ° C]. Then, the stripping steam stream is re-compressed in two stages: in the compressor 16, which is driven by the expander 15, and in the compressor 20, which is driven by an additional energy source. After stream 41b is cooled to 110 ° P [43 ° C] in the outlet cooler (cooling device) 21 and stream 41c is formed, the recycle stream 45 is diverted from the installation as described previously, forming a stream of residual gas 46, which then enters the pipeline pressure marketing 915 psi abs. [6307 kPa (a)].

Brief data on consumption and energy consumption for the technical method shown in FIG. 2 are given in the following table:

table 2

Data p about consumption - lb mol / h [ kg mol / h] Flow Methane Ethane Propane Bhutans + Total 31 12,398 546 233 229 13,726 32 8,679 382 163 160 9,608 33 3,719 164 70 69 4,118 34 12,164 495 174 72 13,213 35 234 51 59 157 513 36 3,248 132 46 nineteen 3,528 37 234 51 59 157 513 38 3,482 183 105 176 4,041 39 8,916 363 128 53 9,685 40 0 0 0 0 0 41 13,863 thirty 0 0 14,095 45 1,475 3 0 0 1,500 46 12,388 27 0 0 12,595 44 10 519 233 229 1,131

- 7,024,494

Selected Components *

Ethane 95.03% Propane 99.99% Bhutans + 100.00%

Power.

Residual gas compression: 5.787 hp [9.514 kW].

* (Based on non-rounded flow rates).

Comparison of the table. 1 and 2 shows that the present invention allows to provide almost the same level of product recovery as the known technical solutions. However, further comparison of the indicators in the table. 1 and 2 shows that the same volume of the finished product was obtained at much lower energy consumption than in the installation, assembled using known technical solutions. Regarding the efficiency of product recovery (which is determined by the amount of ethane recovered per unit capacity), the present invention is more than 6% more economical than the method using known technical solutions shown in FIG. one.

The increase in product extraction efficiency provided by the present invention compared to a method based on known technical solutions (Fig. 1) is mainly associated with two factors. Firstly, the compact arrangement of the heat exchangers in the cooling section of the feedstock 118a and the heat and mass transfer devices in the demethanization section 118e of the processing unit 118 eliminates the pressure drop that occurs due to the presence of connecting pipes in a conventional processing unit. As a result, in the installation made in accordance with the present invention, that part of the feed gas that enters the expander 15 is at a higher pressure than the gas in the installation assembled using already known technical solutions; this allows the expander 15 in the circuit of the present invention to produce the same amount of energy at a higher output pressure than the expander 15 produces in the circuit using already known technical solutions, but at a lower output pressure. Therefore, the distillation section 118c and the absorption section 1186 in the processing unit 118 of the present invention can operate at a higher pressure than the distillation column 18 in the circuit using already known technical solutions, while the level of product recovery remains the same. The result of increasing the working pressure and reducing the pressure drop due to the elimination of the connecting pipelines is that the stripping steam enters the compressor 20 at a significantly higher pressure, thereby reducing the amount of energy needed to bring the residual gas pressure to the pressure level in the pipeline.

Secondly, the use of heat and mass transfer device in the demethanization section 118e for simultaneous heating of the distillation condensate leaving the absorption section 1186, while the resulting steam has the ability to contact with the condensate and release volatile components from it, which is more efficient than using a conventional distillation column with external reboilers. Volatile components are constantly released from the liquid condensate, thereby their concentration in stripped vapors decreases much faster, which increases the efficiency of distillation of light fractions for the present invention.

In addition to increasing the efficiency of processing, the present invention, in comparison with the installations of the current level of technology, has two more advantages. Firstly, the compact design of the processing unit 118 of the present invention replaces five separate pieces of equipment used in the traditional scheme (heat exchangers 10.11 and 13; separator 12; distillation column 18 in FIG. 1) with one unit (processing unit 118 in FIG. 2 ) At the same time, the area required to accommodate the installation is reduced, and the connecting pipelines are eliminated, which leads to lower capital costs for the processing plant, built according to the scheme of the present invention, in comparison with a plant built using already known technical solutions. Secondly, the exclusion from the design of the connecting pipelines means that the processing plant, constructed according to the scheme of the present invention, has much less flange connections compared to the plant constructed using the well-known technical solutions, which reduces the number of potential leaks in such a plant. Hydrocarbons are volatile organic compounds (VOCs), some of which are classified as greenhouse gases, and some can create holes in the ozone layer; this means that the present invention reduces the possibility of emissions that pollute the atmosphere.

Other embodiments

In some cases, it may be necessary to remove the cooling section of the feedstock 118a from the processing unit 118 and use an external heat exchanger 10, for example a heat exchanger 10, as shown in FIG. 10-17. This layout allows

- 8 024494 reduce the dimensions of the processing unit 118, which will help reduce the total cost of the installation and / or reduce the installation schedule (in some cases). It should be noted that in all cases the heat exchanger 10 is either several separate heat exchangers or one multi-pass heat exchanger, a combination of both options is also possible. Each such heat exchanger can be a finned tube heat exchanger, a plate heat exchanger, a brazed aluminum heat exchanger, or another type of heat exchanger, including a multi-pass and / or multi-function heat exchanger.

In some cases, it may be necessary to supply the liquid condensate stream 35 directly to the bottom of the absorption section 1186 through stream 40, as shown in FIG. 2, 4, 6, 8, 10, 12, 14 and 16. In this case, an appropriate expansion device is used (for example, an expansion valve (fourth expansion device) 17), where the condensate expands to the operating pressure of the absorption section 1186, and the resulting expanded flow condensate 40a is supplied as a feed to the bottom of the absorption section 1186 (as shown by dashed lines). In some cases, it may be necessary to mix part of the condensate stream 35 (stream 37) with steam in stream 36 (Fig. 2, 6, 10 and 14) or with a cooled second stream 33a (Fig. 4, 8, 12 and 16) to form mixed stream 38 and directing the remaining portion of the condensate stream 35 to the lower portion of the absorption section 1186 in streams 40 / 40a. In some cases, it may be necessary to mix the expanded condensate stream 40a with the expanded stream 39a (Figs. 2,6, 10 and 14) or with the expanded stream 34a (Figs. 4, 8, 12 and 16), and then apply the mixed stream to the bottom part of the absorption section 1186 as raw material.

If the residual gas is enriched, then the amount of condensate separated in stream 35 may be sufficient to accommodate an additional mass transfer zone in the demethanization section 118e between the expanded stream 39a and the expanded condensate stream 40a, as shown in FIG. 3, 7, 11 and 15, or between the expanded stream 34a and the expanded condensate stream 40a, as shown in FIG. 5, 9, 13 and 17. In this case, heat and mass transfer devices in the demethanization section 118e can be installed in the upper and lower parts so that the expanded condensate stream 40a can be supplied between them. The dashed lines indicate that in some cases it may be necessary to mix part of the condensate stream 35 (stream 37) with steam in stream 36 (FIGS. 3, 7, 11 and 15), or with a second cooled portion of stream 33a (FIG. 5, 9 , 13 and 17) to form a mixed stream 38, while the remaining part of the condensate stream 35 (stream 40) expands to a lower pressure and is supplied between the upper and lower parts of the heat and mass transfer device in the demethanization section 118e as stream 40a.

In some cases, it may be necessary not to mix the cooled first and second parts (streams 32a and 33a), as shown in FIG. 4, 5, 8, 9, 12, 13, 16, and 17. In this case, the cooled first part 32a is sent to the separation section 118G in the processing unit 118 (FIGS. 4, 5, 12 and 13), or to the separator 12 (FIG. . 8, 9, 16 and 17), where the vapor (stream 34) is separated from the liquid condensate (stream 35). The vapor stream 34 enters the expander 15, where it undergoes isentropic expansion to the working pressure of the absorption section 1186, after which the expanded stream 34a is fed as raw material to the lower part of the absorption section 1186 located inside the processing unit 118. The cooled second part of the stream 33a is mixed with the separated condensate separator (stream 35, through stream 37), and the mixed stream 38 is directed to the heat exchange device at the bottom of the cooling section of the feedstock 118a in the processing unit 118 (or to the heat exchanger 10, iysya independent unit relative to the installation 118), where it is cooled to complete condensation. The condensed stream 38a then undergoes rapid evaporation through the expansion valve 14 to the operating pressure of the distillation section 118c and the absorption section 1186, after which the expanded stream 38b is fed to the processing unit 118 in the area between the distillation section 118c and the absorption section 1186. In some cases, it may be necessary to mix only part (stream 37) of the condensate stream 35 with the cooled second part — stream 33 a, and the remaining part (stream 40) to be fed into the lower part of the absorption section 1186 through expansion valve 17. In another case, it may be necessary to direct all the condensate stream 35 to the bottom of the absorption section 1186 through the expansion valve 17.

In some cases, it may be necessary to use an external container to separate the cooled feed stream 31a or the cooled first portion — stream 32a, instead of including the separator section 18G in the processing unit 118. As shown in FIG. 6, 7, 14 and 15, a separator 12 may be used to separate the cooled feed stream 31a into a steam stream 34 and a condensate stream 35. Also, as shown in FIG. 8, 9, 16 and 17, a separator 12 can be used to separate the cooled portion of stream 32a into steam stream 34 and condensate stream 35.

Depending on the amount of heavy hydrocarbons in the feed gas and its supply pressure, the cooled feed stream 31a entering the separation section 118G, as shown in FIG. 2, 3, 10 and 11, or to a separator 12, as shown in FIG. 6, 7, 14 and 15 (or the cooled first part of the stream 32a entering the separation section 118G, as shown in Figs. 4, 5, 12 and 13, or to the separator 12, as shown in Figs. 8, 9, 16 and 17) may not contain a liquid component (since the pressure exceeds the point of start of condensation or cricondenbar). In such cases, there is no condensation in streams 35 and 37 (as shown by dashed lines), so that only steam from the separation section 118G in stream 36 (Figs. 2, 3, 10 and 11), steam from the separator 12 in stream 36 (Fig. 6, 7, 14 and 15), or the cooled second part of the stream 33a (Figs. 4, 5, 8, 9, 12, 13. 16 and 17) are poured into the stream 38; this stream turns into an expanded condensed stream 38b entering the processing unit 118, in the area between the distillation section 118c and the absorption section 1186. In this case, the separation section 118G in the processing unit 118 (Figs. 2-5 and 10-13) or separator 12 (Figs. 6-9 and 14-17) may not be needed.

The characteristics of the feed gas, the dimensions of the installation, available equipment or other factors may indicate that it is not necessary to install the expander 15, or it needs to be replaced with another expansion device (for example, an expansion valve). And although the diagram shows specific expansion devices for each stream, if necessary, other devices can be used instead. For example, the processing mode requires expansion of the fully condensed portion of the feed stream (stream 38a) or the fully condensed recycle stream (stream 45a).

In accordance with the present invention, it is possible to use an external cooling unit for additional cooling of the incoming gas entering the streams of distillation steam and condensate, especially if an enriched incoming gas is used. In such cases, the heat and mass transfer device can be included in the separation section 118G, thereby providing the invention with an additional heat and mass transfer device (either install a gas collection device if the cooled feed stream 31a or the cooled first part of stream 32a does not contain a liquid component), as shown by dashed lines in FIG. 2-5, and 10-13; or the heat and mass transfer device can be included in the separator 12, as shown by dashed lines in FIG. 6-9 and 14-17 thereby provide the invention with an additional heat and mass transfer device. As a heat and mass transfer device, a fin heat exchanger can be used, a plate heat exchanger, a brazed aluminum heat exchanger, or another type of heat exchanger, including multi-pass and / or multi-function heat exchangers. The heat exchange device is designed to provide heat exchange between the flow of the refrigerant (for example, propane) flowing along one stroke of the heat and mass transfer device and the vaporous part of the stream 31a (Fig. 2, 3, 6, 7, 10, 11, 14 and 15) or stream 32a (Fig. 4, 5, 8, 9, 12, 13, 16 and 17), which move upward, while the refrigerant cools the steam and contributes to the formation of additional condensate, which flows down and combines with the condensate removed from the stream 35. Alternatively, conventional gas coolers may be used. to lower the temperature of stream 32a, stream 33a and / or stream 31a with a refrigerant before stream 31a enters separation section 118G (FIGS. 2, 3, 10 and 11) or to separator 12 (FIG. 6, 7, 14 and 15); either the stream 32a will enter the separation section 118G (FIGS. 4, 5, 12 and 13) or the separator 12 (FIGS. 8, 9, 16 and 17).

Depending on the temperature and degree of enrichment of the feed gas, as well as on the amount of components C2 that must be removed from the liquid product stream 44, heating only due to stream 33 may not be sufficient for the condensate leaving the demethanization section 118e to meet the performance requirements product. In this case, additional heating means can be installed in the heat and mass transfer device in the demethanization section 118e using a heat carrier, as shown by dashed lines in FIG. 2-17. Alternatively, it is possible to install another heat and mass transfer device in the lower part of the demethanization section 118e to provide additional heating; or stream 33 can be heated using a coolant before it enters the heat and mass transfer device installed in the demethanization section 118e.

Depending on the type of heat transfer devices selected as heat exchangers for the upper and lower parts of the raw material cooling section 118a, it is possible to combine these heat exchangers into one multi-pass and / or multi-function heat exchanger. In this case, the multi-way and / or multifunctional heat exchanger should have appropriate means for distributing, separating, and collecting stream 32, stream 38, stream 45, and also the stripping steam stream, in order to heat or cool to the desired level.

In some cases, it may be necessary to install an additional mass transfer device at the top of the demethanization section 118e. In this case, the mass transfer device can be placed below the feed point of the expanded stream 39a (Fig. 2, 3, 6, 7, 10, 11, 14 and 15) or the expanded stream 34a (Fig. 4, 5, 8, 9, 12, 13 , 16 and 17) to the lower part of the absorption section 1186, and above the exit point of the cooled second part of the stream 33a from the heat and mass transfer device in the demethanization section 118e.

Less preferred for the embodiments of the present invention shown in FIG. 2, 3, 6, 7, 10, 11, 14, and 15, is the installation of a separator for the cooled first part of the stream 32a, a separator for the cooled second part of the stream 33a; wherein the steam streams separated in the separators are mixed to form a steam stream 34, and the condensate streams are mixed and form a condensate stream 35. Another less preferred embodiment of the present invention is to cool the stream 37 in a separate heat exchanger located in the cooling section of the feedstock 118a, as shown in FIG. 2, 3, 4, 5, 6, 7, 8 and 9 or its supply through a separate stroke in the heat exchanger

- 10,024,494

10, as shown in FIG. 10, 11, 12, 13, 14, 15, 16, and 17 (instead of mixing stream 37 with stream 36 or stream 33a to form a combined stream 38); wherein the expansion of the cooled stream is carried out in a separate expansion device, and the expanded stream is supplied to the intermediate zone of the absorption section 1186.

It should be noted that the relative amount of raw materials in each branch of the separated vaporous raw materials depends on several factors, including the pressure and composition of the raw gas, the amount of heat that can be extracted from the raw material, as well as the available amount of power.

An increase in the supply of raw materials to the zone above the absorption section 1186 can lead to an increase in the degree of product recovery with a decrease in the power received in the expander, which, in turn, leads to an increase in the power required for re-compression of the product. An increase in the supply of raw materials to the area below the absorption section 1186 reduces the level of power consumption, but the level of product recovery may also decrease.

The present invention provides an increased degree of extraction of components C ₂ , C ₃ , and heavier hydrocarbons, or components C ₃ and heavier hydrocarbons by the amount of auxiliary media consumed necessary for the operation of the technical method. The saving of consumed auxiliary media necessary for the functioning of the technical method can be manifested in the form of a decrease in power consumption for compression or re-compression; reducing the power needed for an external cooling installation; reduction of energy required for additional heating; or in the form of a combination thereof.

Described here are preferred embodiments of the invention; specialists with an appropriate level of technical training can find other options or make changes to those described here (for example, adapt the invention to work in other modes, using a different type of raw material or with changing other requirements), without deviating from the essence of the present invention defined in its next formula.

Claims (25)

CLAIM 1. A method for separating a gas stream (31) containing methane, components C2, components C3 and heavier hydrocarbon components into a volatile fraction of residual gas (46) and a relatively less volatile fraction (44) containing the bulk of these components C2, components C3 and heavier hydrocarbon components or these components C3 and heavier hydrocarbon components, while (1) the specified gas stream (31) is divided into the first (32) and second parts (33); (2) wherein said vaporous stream is directed to an additional heat and mass transfer device, where it is cooled using an external cooling agent until additional condensate forms; (2) an additional heat and mass transfer device is placed inside the gas collection device, including one or more strokes for the passage of the cooling agent; (2) an additional heat and mass transfer device is placed inside the gas collection device, including one or more strokes for the passage of the cooling agent; (2) said processing unit (118) is connected to a fourth expansion device (17) and receives an expanded condensate stream (40a) and directs it to the zone between the upper and lower parts of the heat and mass transfer device. (2) a heat exchange device (10) connected to said first separation device for receiving the first part (32) and cooling it (32a); (2) said vapor stream is directed to an additional heat and mass transfer device for additional cooling until additional condensate forms; (2) an additional heat and mass transfer device is placed inside the gas collection device, including one or more strokes for an external cooling agent; (2) an additional heat and mass transfer device is placed inside the gas collection device, wherein said heat exchange device has one or more strokes for an external cooling agent; (2) said expanded (17) remaining part (40) of at least one condensate stream (35) is supplied (40a) to said processing unit (118), into the space between the upper and lower parts of the heat and mass transfer device. (2) said expanded (17) at least part (40) of at least one condensate stream (35) is supplied (40a) to said processing unit (118), in the space between the upper and lower parts of the heat and mass transfer device. 2. The method according to claim 1, in which (a) said cooled first part (32a) of the stream is mixed with said cooled second part (33a) of the stream, thereby forming a partially condensed gas stream (31a); (b) said partially condensed gas stream (31a) is supplied to a separation device (12), where it is separated into a vapor stream (34) and at least one condensate stream (35); (c) said vapor stream (34) is divided into first (36) and second (39) streams; (i) at least a portion (40) of at least one condensate stream (35) is expanded (17) to a lower pressure and then fed as an additional feed stream (40a) to the bottom of said second absorption device. (2) said first part (32) of the stream is cooled (10); (3) said condensate is poured into at least one condensate stream (35) separated by separation. (3) said gas collection device is connected to a heat exchange device (10) and is intended to receive a cooled first part (32a) of the stream and its direction to an additional heat and mass transfer device for further cooling using an external cooling agent; (3) said gas collection device is connected to a mixing device and is designed to receive a cooled gas stream (31a) and direct it to an additional heat and mass transfer device for further cooling using an external cooling agent; (3) a heat and mass transfer device installed in the demethanization section (118e) in the processing unit (118) and connected to the first separation device to receive the second part (33) and cool it (33 a); (3) said condensate is poured into at least one condensate stream (35) separated by separation. (3) said cooled first portion (32a) of the stream is fed to a gas collecting device and sent to said additional heat and mass transfer device for additional cooling with an external cooling agent; (3) said chilled gas stream (31a) is supplied to a gas collecting device and sent to said additional heat and mass transfer device for additional cooling using an external cooling agent; 3. The method according to claim 2, in which (a) said first stream (36) is mixed with at least a portion (37) of at least one condensate stream, forming a mixed stream (38); (b) the specified mixed stream (38) is cooled (10) to almost complete condensation (38a), and then expanded (14) to a lower pressure, while cooling (38y) even more; (c) the resulting expanded cooled mixed stream (38b) as the specified feed is fed into the zone between the first and second absorption devices; (i) the remaining part (40) of said at least one condensate stream (35) is expanded (17) to a lower pressure and (40a) is supplied as said additional feed to the lower part of said second absorption device. (3) said second part (33) of the stream is cooled (118e); (4) the second expansion device (15) is configured to connect to the specified gas collection device, is designed to receive the cooled first part (34) of the stream and expand it to the specified reduced pressure (34a) and connected to the second absorption device to supply the cooled expanded first part (34a) a stream to its lower portion as said feedstock. (4) the second separation device is connected to the specified gas collection device and is designed to receive a cooled gas stream (34) and its separation into the first (36) and second (39) streams. (4) a mixing device connected to the specified heat exchanger device (10) and heat and mass transfer device and designed to receive the cooled first (32a) and second (33a) parts of the stream and the formation of the cooled gas stream (31a, 34); (4) the obtained additionally cooled first part (34) of the stream is expanded (15) to the indicated lower pressure, and then it is fed as raw material (34a) to the lower part of the second absorption device. (4) the obtained additionally cooled gas stream (34) is divided into first (36) and second (39) streams. 4. The method according to claim 1, in which (a) said first part (32) of the stream is cooled (10) and then expanded (15) to a lower pressure (34a); (b) said second part (33) of the stream is cooled (118e, 10) essentially until it is completely condensed (38a) and then expanded (14) to a lower pressure, while cooling (38b) even more; (c) the resulting expanded cooled second portion (38b) of the stream as the aforementioned feed is fed into the zone between the first and second absorption devices; (i) the obtained expanded and cooled first part (34a) of the stream is fed as said raw material to the lower part of the second absorption device. (4) said chilled first part (32a) of the stream is mixed with said chilled second part (33a) of the stream, thereby forming a chilled gas stream (31a, 34); (5) a second separation device connected to said mixing device for receiving and separating the cooled gas stream (31a, 34) into first (36) and second (39) streams; 5. The method according to claim 4, in which (a) the specified first part (32) of the stream is cooled (10) to its partial (32a) condensation; (b) the resulting partially condensed first portion (32a) of the stream is fed to a separation device (12), where it is separated into a vapor stream (34) and at least one condensate stream (35); (c) said vapor stream (34) is expanded (15) to a lower pressure and fed as said first feed stream (34a) to the bottom of said second absorption device; (i) at least a portion (40) of at least one condensate stream (35) is expanded (17) to a lower pressure and fed as an additional feed stream (40a) to the bottom of said second absorption device. (5) said chilled gas stream (31a, 34) is divided into first (36) and second (39) streams; (6) a fourth expansion device (17) is connected to a separation device (12), is designed to receive at least part (40) of at least one condensate stream (35) and expand to said reduced pressure and connected to a second absorption device for supplying the expanded condensate stream (40a) to its lower part as additional secondary raw materials. (6) said heat exchange device (10), also connected to a second separation device, for receiving and substantially cooling the first stream (36, 38) until it is completely condensed (38a); 6. The method according to claim 5, in which (a) said second part (33) of the stream is cooled (118e) and then mixed with part (37) of at least one condensate stream (35), forming a mixed stream (38); (b) said mixed stream (38) is cooled (10) to its full (38a) condensation and then expanded (14) to a lower pressure, cooling (38b) even more; (c) the resulting expanded cooled mixed stream (38b) as said raw material is supplied to the zone between the first and second absorption devices; (i) the remaining part (40) of said at least one condensate stream (35) is expanded (17) to a lower pressure and then fed as said additional feed (40a) to the lower part of said second absorption device. (6) said first stream (36, 38) is cooled (10) until it is completely (38a) condensed, then expanded (14) to a lower pressure, thereby cooling (38b) even more; (7) a first expansion device (14) connected to said heat exchange device (10) for receiving and expanding an almost completely condensed stream (38a) to a lower pressure; 7. The method according to claim 2 or 5, characterized in that (1) said heat and mass transfer device is installed in the upper and lower parts; (7) the obtained expanded cooled first stream (38b) is fed as a raw material into the zone between the first and second absorption devices installed in the distillation section (118c) and absorption section (1186), respectively, in the processing unit (118), while the first device absorption is located above the second; (8) the first and second absorption devices located in the distillation section (118c) and the absorption section (1186) respectively in the specified processing unit (118) connected to the first expansion device (14) and designed to receive the specified extended and 8. The method according to claim 3 or 6, characterized in that (8) said second stream (39) is expanded (15) to said lower pressure and fed as a feed (39a) to the bottom of said second absorption device; (9) a second expansion device (15) connected to said second separation device for receiving and expanding the second stream (39) to said reduced pressure (39a), the second expansion device being further connected to the second absorption device for feeding (39a) an expanded second stream to its lower part as a raw material; 9. The method according to claims 2, 3, 5-8, characterized in that the separation device is placed in the separation section (118ί) in said processing unit (118). (9) in the upper part of said first absorption device, a stripping vapor stream (41) is generated and heated (10); (10) a steam collection device located in the absorption section (118b) in the processing unit (118), connected to the first absorption device and designed to receive a stream of stripping steam coming from the top of said first absorption device (118c); 10. The method according to claim 1, characterized in that (1) the gas collecting device is placed in the separation section (118G) in said processing unit (118); (10) the resulting heated stripping vapor stream (41a) is compressed (16, 20) to a higher pressure (41b, 41c, 416), and then it is separated into a residual gas volatile fraction (46) and a compressed recirculated stream (45); (11) wherein said heat exchange device (10) is additionally connected to a steam collection device and is intended to receive and heat said stream of stripping steam, thereby partially contributing to cooling (10) in the method steps (2) and (6); 11. The method according to claim 4, characterized in that (1) the gas collecting device is placed in the separation section (118G) in said processing unit (118); - 11,024,494 cooling in step (3), wherein more volatile components are simultaneously released from the specified stripping condensate stream, after which the specified heated and purified from light fractions stripping condensate stream is removed from the processing unit as the indicated relatively less volatile fraction (44); (11) said compressed recycle stream (45) is cooled (10) until it is completely (45a) condensed; (12) a compressor device (16, 20) connected to a heat exchange device (10) for receiving a heated stream (41a) of stripping steam and compressing it to a higher pressure (41b, 41c); 12. The method according to PP.2, 3, 5-9, characterized in that (1) inside the separation device (12) place an additional heat and mass transfer device, including one or more strokes for the passage of the cooling agent; - 12,024,494 (1) said heat and mass transfer device is installed in the upper and lower parts of the demethanization section; (12) the resulting substantially condensed compressed recycle stream (45a) is expanded (22) to the indicated lower pressure and fed as raw material (45b) to the top of the first absorption device; (13) a cooling device (21) connected to said compressor device (20) for receiving a compressed stream (41c) of stripping steam and its (416) cooling; - 13,024,494 chilled first stream (38b), fed as a raw material into the zone between said first and second absorption devices, wherein the first absorption device is located above the second; 13. The method according to claims 1-12, characterized in that said heat and mass transfer device includes one or more strokes for an external cooling agent to maintain the temperature to which the installation has warmed up due to the second part of the stream (33) and which is sufficient to separate more volatile components from the specified stream of distillation condensate. (13) heating (10) of said distillation vapor stream (41) is carried out in one or more heat exchange devices (10), which allows at least partial cooling (10) in steps (2), (6) and (11) ); - 14484949 (c) a first expansion device (14) is connected to said heat exchange device (10) for receiving and expanding the fully condensed mixed stream (38a) to a lower pressure (38b); (i) the first and second absorption devices connected to the first expansion device (14) and designed to receive said expanded and cooled mixed stream (38b) fed as said raw material into the zone between said first and second absorption devices; (e) a fourth expansion device (17) connected to said separation device (12) for receiving the remaining part (40) of at least one condensate stream (35) and expanding it to said reduced pressure (40a) and connected to the second an absorption device for supplying an expanded condensate stream (40a) to its lower part as said additional secondary raw materials. (14) a third separation device connected to said cooling device (21) for receiving a cooled compressed stream (416) of stripping steam and separating it into a volatile fraction (46) of residual gas and a compressed recycle stream (45); 14. Installation for implementing the method according to claim 1, comprising (1) a first separation device, where the gas stream (31) is divided into first (32) and second (33) parts; (14) from the bottom of said second absorption device, the stripping condensate stream is collected and heated in a heat and mass transfer device located in the demethanization section (118e) in said processing unit (118), thus providing at least partial - 15,024,494 (1) said heat and mass transfer device is installed in the upper and lower parts; 15. The apparatus of claim 14, wherein (a) said mixing device is connected to a heat exchange device (10) and to said heat and mass transfer device and is adapted to receive cooled first (32a) and second (33a) parts of the stream and form a partially condensed gas stream (31a); (b) a separation device (12) is connected to said mixing device and is adapted to receive a partially condensed gas stream (31a) and to separate it into a vapor stream (34) and at least one condensate stream (35); (c) said second separation device is connected to said separation device (12) and is adapted to receive said vapor stream (34) and to separate it into first (36) and second (39) streams; (15) said heat exchange device (10) is additionally connected to a third separation device for receiving the compressed recirculation stream (45) and cooling it to its substantial (45a) condensation, providing at least partial heating (10) in step (11) method; (15) the amounts and temperatures of said feed streams (45b, 38b, 39a) sent to the first and second absorption devices are effective for maintaining the temperature in the upper part of the first absorption device, such that the main parts of the components are in a relatively less volatile fraction (44 ) are retrieved. 16. Installation according to claim 15, in which (a) an additional mixing device is connected to the second expansion device and separation device (12), it is designed to receive the first stream (36) and at least part (37) of at least one stream (35) condensate and formation of a mixed stream (38); (b) wherein said heat exchange device (10) is additionally connected to an additional second mixing device for receiving the mixed stream (38) and its (38a) substantially cooling to almost complete condensation; (16) a third expansion device (22) connected to said heat exchanger device (10) and designed to receive a substantially condensed compressed recycled stream (45a) and expand it to said reduced pressure (45b), wherein said third expansion device (22) connected to a first absorption device for supplying an expanded recirculation stream (45b) to its top as a feed; 17. The installation according to 14, in which (a) the heat exchange device (10) is additionally connected to the specified heat and mass transfer device, it is designed to receive the cooled second part (33 a, 38) of the stream and its further cooling until its complete (38a) condensation ; (b) a first expansion device (14) is connected to said heat exchanger device (10) and is intended to expand the almost completely condensed second part (38a) of the stream to a lower pressure (38b); (c) the first and second absorption devices are connected to the first expansion device (14) and are designed to receive the specified expanded and cooled second part (38b) of the stream fed as said raw material into the zone between the said first and second absorption devices; (i) a second expansion device (15) is connected to the specified heat exchanger (10), is designed to receive the cooled first part (32a) of the stream and its expansion to the specified reduced pressure (34a) and connected to the second absorption device to supply the expanded first part ( 34a) flow to its lower part as a raw material. (17) a condensate collecting device disposed in the processing unit (118) connected to a second absorption device and adapted to receive a stream of distillation condensate coming from the bottom of said second absorption device; 18. Installation according to claim 17, in which (a) the heat exchange device (10) is connected to the first separation device, designed to receive and cool the first part (32) of the stream to its partial (32a) condensation; (b) a separation device (12) is connected to said heat exchange device (10) and is intended to receive a partially condensed first part (32a) of the stream and to separate it into a vapor stream (34) and at least one condensate stream (35); (c) a second expansion device (15) is connected to said separation device (12), for receiving and expanding the vapor stream (34) to said reduced pressure (34a), and connected to a second absorption device for supplying the expanded vapor stream (34a) to its lower part as said primary raw material; and (i) a fourth expansion device (17) is connected to a separation device (12), designed to receive at least part (40) of at least one condensate stream (35) and expand to said reduced pressure (40a) and connected to a second an absorption device for supplying an expanded stream (40a) of condensate to its lower part as additional raw materials. (18) wherein said heat and mass transfer device is connected to a condensate collecting device and is intended to receive and heat said stream of distant condensate, thereby at least partially providing cooling in step (3) of the method, more volatile additionally being released from the stream of distillation condensate components, after which the specified heated and freed from light fractions stream of distillation condensate is removed from the processing unit (118) as a relatively less volatile fraction (44); 19. Installation according to claim 18, in which (a) an additional mixing device is connected to a heat and mass transfer device and a separation device (12) and is designed to receive a cooled second part (33 a) of the stream and at least part (37) of at least one condensate stream (35) and mixed stream formation (38); (b) wherein said heat exchange device (10) is further connected to said additional mixing device for receiving the mixed stream (38) and substantially cooling it until it is completely (38a) condensed; (c) a first expansion device (14) is connected to said heat exchanger device (10) and is designed to receive and expand an almost completely condensed mixed stream (38a) to a lower pressure (38b); (i) the first and second absorption devices are connected to the first expansion device (14) and are designed to receive said expanded and cooled mixed stream (38b) fed as said raw material into the zone between said first and second absorption devices; (e) the fourth expansion device (17) is connected to the specified separation device (12), is designed to receive the remaining part (40) of at least one condensate stream (35) and expand to the specified reduced pressure (40a) and connected to the second device absorption to supply the expanded stream (40A) of the condensate in its lower part as mentioned additional raw materials. (19) a control device for controlling the quantities and temperatures of said feed streams (45b, 38b, 39a) sent to the first and second absorption devices to maintain the temperature in the upper part of the first absorption device at a level at which the main parts of the components are relatively less volatile fractions (44) are recovered. 20. Installation for PP, 16, 18 or 19, characterized in that 21. Installation according to claims 15, 16, 18, 19 or 20, characterized in that the separation device is located in said processing unit (118). 22. Installation according to claim 14, characterized in that (1) the gas collection device is located in the separation section (1181) in said processing unit (118); 23. Installation according to claim 17, where (1) the gas collecting device is located in the separation section (1181) in said processing unit (118); 24. Installation according to claims 15, 16, 18-20 or 21, characterized in that (1) an additional heat and mass transfer device is placed inside the separation device (12), including one or more strokes for passing the cooling agent; 25. Installation according to claims 14-23 or 24, characterized in that in said heat and mass transfer device there is one or several strokes for an external heat carrier to maintain the temperature to which the installation has warmed up due to the second part (33) of the flow and which is sufficient to separate more volatile components from the specified stream of distant condensate.