RU59053U1 - INSTALLATION FOR CATALYTIC REFORMING OF GASOLINE FRACTIONS - Google Patents

Abstract

The installation for carrying out catalytic reforming of gasoline fractions includes a raw material purification unit and a purified raw material reforming unit, the reforming unit including a reactor in which a heat supply unit is arranged in the reaction zone formed by a plurality of heat pipes, the total surface area of which provides the necessary reaction thermal energy reforming reactions. In the rhyming reactor, a mode close to isothermal is preferably carried out. The utility model can be used in oil refining.

Description

The installation is designed to carry out catalytic reforming of gasoline fractions and can be used in oil refining.

A typical gasoline fraction reforming unit includes a feed purification unit, a reforming unit, and a reforming product separation unit if light gasoline fractions are reformed to produce individual aromatic hydrocarbons. Each unit includes devices and other equipment for the operation of the unit in one form or another in accordance with its purpose.

Hydrotreating gasolines is carried out in modern reformers in the purification unit in order to reduce the content of sulfur, nitrogen, oxygen, halogen and metal compounds to the required level. The purification unit includes a hydrotreating reactor filled with aluminum-cobalt-molybdenum or aluminum-nickel-molybdenum catalyst (Edited by Ogorodnikov SK, Petrochemist Handbook. L .: Chemistry, 1978, v.2, p.156). For reducing the sulfur content in the raw material reforming below 0.1 million ^-1 used adsorption method for removing sulfur and purification unit complement adsorber (US №4225417, C 10 G 23/02, 1980 YG), or an adsorbing reactor and charged between adsorbent layers hydrogenation catalyst (RU No. 2081151, C 10 G 61/06, 1997) In the purification unit, purified gasoline is obtained as the main product, which is sent to the reforming unit.

The reforming unit includes three to five reactors with a stationary catalyst or a multi-section reactor with a moving bed of catalyst for catalytic reforming (Ed. Ogorodnikova SK, Petrochemist Handbook. L .: Chemistry, 1978, v.2, p.167-171) . Reforming is usually carried out in three to five stages with intermediate heating of partially converted raw materials, since the process proceeds with a significant thermal effect - 250-500 kJ / kg. The temperature conditions of the reactors of industrial reefing plants are close to adiabatic.

Any chemical process, however, is preferably carried out in a certain optimal temperature range, for catalytic processes this is associated not only with the quantity and quality of the product, but also with the duration of the catalyst. The maximum yield of the product is obtained in an isothermal process, one of the conditions for more or less complete approximation to which is the continuous compensation of the thermal effect of the reaction.

In close to isothermal conditions, gasoline fractions are reformed in the fluidized bed of the oxide catalyst during the hydroforming process, but to ensure the thermal balance of the process, coolant is added to the circulating catalyst and the hydrogen-containing gas is significantly overheated before being fed into the reactor (Ed. By Mukhlenova I.P. and Pomerantseva V.M. Fluidized Bed Catalysis (Leningrad: Chemistry, 1978, p. 214-216). The main disadvantages of this process are due to the low activity of the oxide catalyst.

A typical installation for the processing of gasoline fractions in order to obtain a component of motor gasolines with an octane rating of 85 m. (prototype, Gulyaev V.A., Lastovkin E.M. et al. Industrial catalytic reforming plants. M: Chemistry, 1984, p. 57-63) includes a hydrotreating reactor, a stripping column, a hydrocarbon gas treatment absorber, an absorbent regeneration column reforming reactors, adsorber dryer,

circulation compressor, stabilization column, hydrotreating and reforming reactor furnaces, steam and stabilization column furnaces, zeolite regeneration, pumps, heat exchangers, separators. At the installation in the raw materials purification unit, the hydrotreating of the raw materials is carried out with stripping of the catalysis, with the absorption cleaning of the stripped gases from hydrogen sulfide and the regeneration of the absorbent; in the reforming unit, refined feedstock is reformed in three adiabatic reactors with intermediate heating of the feedstock, hydrogen-containing gas is isolated from the reforming product, dried with a zeolite adsorbent, the liquid reforming product is stabilized to produce fatty gas and stable high-octane gasoline.

The proposed new installation for the catalytic reforming of gasoline fractions allows reforming in one stage, that is, in a single reactor, close to the isothermal temperature regime and includes a reforming reactor in which thermal energy is supplied to the reaction zone formed by the stationary catalyst layer using heat pipes which are the most efficient means of heat (heat capacity - up to 20 kW / cm ^2, the heat transfer rate is limited by the limit of audible) that allows ermostatirovanie and temperature regulation.

The installation for the catalytic reforming of gasoline fractions includes a raw material purification unit and a refined raw material reforming unit and is characterized in that the reforming unit includes a reforming reactor in which a heat supply unit is placed in the reaction zone formed by a plurality of heat pipes, the total surface area of which provides entry reactions necessary for the implementation of thermal energy reforming reactions.

Heat pipes are described in the book by Dan P.D. and Ray D.A. “Heat pipes” (M .: Energy, 1979). At reforming temperatures, the reduced fluid is used as the working fluid of the heat pipe.

the state of sodium or lithium The heat pipe in the reactor operates as follows. Heat is supplied from an external source to a part of the surface of the heat pipe - to the heating zone (evaporation zone), the working fluid also evaporates in the condensation zone, which is cooled when the surface of the heat pipe contacts the reaction zone in which the endothermic reforming process takes place, and the vapor of the working fluid the release of thermal energy, which is absorbed by the reaction medium during heat transfer with the surface of the heat pipe. Condensate returns through the capillary channels of the wick to the evaporation zone. The total surface area of the heat pipes ensures that the amount of thermal energy necessary for the implementation of the reforming reactions enters the reaction zone. The heat transfer surface in a reactor with heat pipes is 25% lower than in a tubular reactor with boiling water as a coolant.

Heat is supplied to the heat pipe heating zone by any method accepted in the art: by an open flame during fuel combustion, convective heat exchange with various heat carriers, using wave processes. The coolants can then be used to heat raw materials or other plant streams.

A possible reactor design is described in the application for utility model 2005132591/22 of 10.24.05 (positive decision of 01.16.06). The size of the heat pipes and their quantity are determined by the value of the thermal effect of the reforming process and the volume of processed raw materials.

The structure of the installation units ensures their functioning in any known embodiment. More possibilities for variations are presented by the raw material purification process implemented in the purification unit, while the use of a new type of reactor in the reforming unit leaves the possibility of changing only its design and equipment operating modes. One-stage reforming of gasoline fractions simplifies reforming and the use of a reactor

isothermal allows you to increase the speed of the process and the depth of conversion of raw materials.

The raw materials purification unit of the reforming installation includes a furnace and / or heat exchangers for heating the raw materials, as well as a hydrotreating reactor for removing sulfur compounds from the raw materials, in which hydrogen compounds of sulfur, nitrogen, halogens and oxygen-containing compounds, as well as unsaturated compounds on conventional hydrotreating catalysts, or hydrogenation and adsorption, for example, according to methods US No. 4225417, C 10 G 23/02, 1980 or RU No. 2081151, C 10 G 61/06, 1997. The content of impurities in the feed should be (no more): arsenic, lead and copper - 1 · 10-3 mg / kg, nitrogen - 1 mg / kg, water - 10 mg / kg. The permissible sulfur content in the feed depends on the catalyst used and for effective platinum-rhenium catalysts it should be below 1 mg / kg, preferably below 0.1 mg / kg. Such deep desulfurization is carried out using adsorption of hydrogen sulfide or organic sulfur compounds.

Hydrogenation of organometallic impurities of the raw materials is carried out at a temperature of 330-380 ° C, a pressure of up to 4 MPa, a volumetric feed rate of up to 10 h ^-1 , the multiplicity of circulation of a hydrogen-containing gas of 80-500 m ³ / m ³ . The installation, in addition to the hydrotreating reactor, also includes a separator for separating the hydrogen-containing gas and a stripping column for stripping the volatile hydrotreating products. The purification unit may also include an absorber for removing sulfur from the stripped gases and an absorbent regeneration column. Alternatively, at least one adsorber or adsorber-reactor may be used to remove sulfur compounds from hydrotreating products. The adsorber is filled with an adsorbent, preferably based on manganese oxide, and the reactor-adsorber is filled with an adsorbent catalyst that hydrogenates sulfur compounds and adsorbs hydrogen sulfide and other impurities, or with layers of a platinum-containing hydrogenation catalyst and adsorbent. The sulfur removal process in the adsorber is carried out in a hydrogen medium at a temperature of 340-460 ° C and a pressure of up to 5

MPa, or in the absence of hydrogen at a temperature of 260-538 ° C. The adsorber stream or a stable hydrotreating product with the desired sulfur content is sent to the reforming unit.

The purified raw material enters the reforming unit - into the furnace, where it is heated to the reforming temperature, then to the reforming reactor. The reactor includes a unit for supplying heat to the reaction zone formed by a plurality of heat pipes, the total surface area of which provides the heat energy necessary for the reforming reactions to enter the reaction zone. In the reactor, the space between the heat pipes is filled with a reforming catalyst. The contact of the feedstock with the catalyst is carried out at a temperature of 480-530 ° C, with increasing temperature during the run as the catalyst is deactivated, at a pressure of 1.5-4 MPa, a bulk feed rate of 1.5-2 h ^-1 , with a multiplicity of circulation 500-1600 m ³ / m ³ . Any known reforming catalysts may be used.

The reforming unit includes heat exchangers and a refrigerator for cooling the reforming product, a separator for separating the hydrogen-containing gas from the liquid reforming products, a compressor for circulating the hydrogen-containing gas, a column for stabilizing the liquid reforming products. The installation may also include at least one adsorber to remove water vapor from a hydrogen-containing gas during their adsorption on zeolites. It is preferable to use at least two adsorbers, alternately operating in the modes of adsorption and regeneration for continuous drying of a hydrogen-containing gas. The zeolite adsorbent is regenerated by heated, dried hydrogen-containing gas.

A hydrogen-containing gas and a stable liquid product, a component of high-octane gasoline or a concentrate of aromatic hydrocarbons, are removed from the reforming unit. In the latter case, the installation may also include a separation unit, in which by known methods from

aromatic hydrocarbon concentrate emit pure substances. Hydrogen-containing gas is sent to the purification unit for mixing with the feed.

A variant of a gasoline reforming unit with a new type of reactor is shown in the figure. The cleaning unit of the installation includes a T-1 heat exchanger and R-1 and R-2 adsorber reactors. The reforming unit includes P-1 and P-2 furnaces, R-3 reforming reactor, T-2 and T-3 heat exchangers, HV-1 and HV-2 air coolers, S-1 separator, A-1 and A-2 adsorbers , circulation compressor CK, compressor separator S-2, stabilization column K-1, reflux tank S-3, pumps N-1 and N-2. Installation works as follows. Raw material I — the gasoline fraction 85–180 ° С — is mixed with the circulating hydrogen-containing gas VIII, heated with the heat of the reforming product in the T-1 heat exchanger, and sent to the R-1 and P-2 adsorber reactors for purification from sulfur compounds and other impurities. The contact of the feedstock with an adsorbent catalyst based on zinc oxide (zinc oxide 83%, alumina 13%, nickel oxide 2%, molybdenum oxide 2%) is carried out at a temperature of 350-400 ° C, a pressure of 3.5 MPa, the volumetric velocity of the gasoline fraction 1.5 h ^-1 . Purified feedstock II with a sulfur content of less than 1 mg / kg is removed from the R-2 reactor, heated to 480 ° С in the P-1 furnace and sent to the R-3 reforming reactor, into which the reforming catalyst is loaded, forming a reaction zone in the space between the heat pipes . The reforming reactor is built into the P-2 furnace, in which the evaporation zone of the heat pipes is heated. As the working fluid in the heat pipes, molten sodium is used. With the thermal effect of the reforming process of 500 kJ / kg of raw materials and a heat supply of 0.45 kcal / cm ² · h per 1 kg of catalyst, about 533 cm ² of heat transfer area will be required, or about half as much - per 1 kg of raw material. To obtain isothermal conditions in the reactor, the diameter of the heat pipe and the maximum removal of catalyst particles from its surface should be appropriately selected. A heat pipe with a diameter of 30 mm allows you to get the maximum horizontal gradient

temperature 3 ° C in the annular layer of the reforming catalyst with an external diameter of 40 mm The contact of the feed mixture with the catalyst is carried out at a temperature of 480-530 ° C, a pressure of 3.2 MPa, a volumetric feed rate of the gasoline fraction of 2 h ^-1 .

The reforming product III is cooled in heat exchangers T-1, T-2 and refrigerator XB-1 and in the separator C-1, hydrogen-containing gas V is separated from the condensed reforming products VI. Hydrogen-containing gas is sent for zeolite drying to one of the adsorbers, which alternately operate in the adsorption mode. The dried gas is sent to the separator of the C-2 compressor and the Central circulation compressor through the T-2 heat exchanger, where it is heated by the heat of the reforming product, the stream of circulating hydrogen-containing gas VIII is fed to the raw material of the reforming I. Part of the dried hydrogen-containing gas IX is used for regeneration of the adsorbent (regeneration circuit in the diagram is not shown).

The liquid product of reforming VI from the C-1 separator is pumped by the N-1 pump to the T-3 heat exchanger, where it is heated by the heat of the bottoms product of the stable gasoline column XII, and sent to the K-1 stabilization column. The cube of the column is heated with the heat of the reforming product IV, the vapors from the top of the column are cooled in an XB-2 air cooler, and irrigation XI and propane-butane fraction X are taken from the C-3 tank with pump N-2, fuel gas VII is sent to the fuel network.

Claims (1)

Installation for the implementation of catalytic reforming of gasoline fractions, including a raw material purification unit and a refined raw material reforming unit, characterized in that the reforming unit includes a reactor in which a site for supplying heat to the reaction zone formed by heat pipes, the total surface area of which provides entry to the reaction zone, is located necessary for the implementation of thermal energy reforming reactions.