JPS5940187B2 - Light oil manufacturing method - Google Patents

Description

Detailed Description of the Invention The present invention relates to a method for producing aromatic light oil and olefin-rich petrochemical raw material gas in high yield by thermally decomposing mixed or paraffinic heavy oil, and is disclosed in Patent No. 702.
No. 391 relates to improvements in [Method for producing low viscosity heavy oil and asphalt by thermal decomposition of heavy oil using internal heating method].

Since the oil shock that occurred in the fall of 1971 due to policy changes in Arab oil-producing countries, diversification of Japan's crude oil supply sources has been discouraged, and Middle Eastern crude oil sources such as Indonesia, Minas, China,
Attempts are being made to switch to Daqing crude oil, but these crude oils have a freezing point of 30 degrees Celsius or higher, and a low light oil content, so domestic refiners avoid purchasing them.

Therefore, effective uses other than living, such as power plants, have not been developed.

As a countermeasure to this problem, the present inventor first proposed patent No. 7023.
No. 91 was proposed, but even if the liquid phase part was pulverized and injected into the combustion gas at a temperature of 1000°C or higher, the decomposition reaction did not progress sufficiently with a residence time of less than 100 milliseconds, resulting in a tar-like substance that was deposited near the reactor outlet. I have experienced cases where pipes were frequently blocked and operations had to be interrupted.

Therefore, first, the high-molecular paraffin content is mainly decomposed in a known external heating type tube furnace 3 under mild conditions of 450°C or less to reduce the molecular weight, and the gas phase is increased at the same temperature. 1 to an internal thermal cracking furnace 8, and the liquid phase is reacted under separate conditions in a liquid phase reaction tank 5 (or 6) to prevent tar or coke from accumulating in the internal thermal cracking reactor. At the same time, the yield of light oil could be significantly improved.

In addition, the liquid phase portion is heated to 450°C or higher by an internal heating method using superheated steam and/or gas containing hydrogen, carbon monoxide, etc. over a sufficient reaction time in the liquid phase reaction tank 5 or 6, so that it is highly aromatic. It is possible to produce a coke suitable as activated carbon or a hydrogen raw material by using a binder for electrodes with a carbon content or by extending the reaction time.

In the present invention, the main thermal decomposition reaction is carried out separately in the liquid phase and the gas phase by an internal heating method under optimal conditions, and there is no fear of coke formation due to over-decomposition.

Therefore, the properties of the produced oil are relatively stable as it does not contain substances that are easily polymerized such as diolefin, and even when hydrogenated, the amount of hydrogen consumed is low and it is economical.

In addition, the supply and demand for light crude oil such as Arabian Light is close, and the supply tends to increase due to increased production of heavy crude oil such as Daqing and Minas.

According to the present invention, it is possible to decompose not only any petroleum-based heavy oil, but also non-petroleum-based tar sand oil, shale oil, coal-based tar oil, etc., by reducing hydrogen in the heat medium in the thermal cracking reaction system using an internal thermal method. It is possible to thermally decompose the gas and make it lighter by increasing the partial pressure of the gas.

The invention will now be described in detail with reference to the drawings.

This flow sheet includes the three-stage decomposition method of the liquid phase portion according to claim 2.

Mixed base or paraffin base crude oil O6r is fed from the bottom right of the drawing in the direction of the arrow and is heated to 20° by heat exchanger 12°13.
Naphtha fraction Np heated to around 0°C and having a boiling point of 200°C or less is removed from the top of the evaporation tower 1, and the bottom oil is sent to the heating furnace 3.

The heating furnace 3 is a known external heating type heating furnace, but the outlet temperature of the furnace is kept below 450° C., and only the polymeric paraffin portion is slightly decomposed.

If there is a risk that coke may be deposited in the furnace pipeline with mixed base crude oil, an appropriate amount of steam STM may be added at the entrance of the furnace as shown by the dotted line.

Steam STM is generated by supplying water W to the waste heat boiler 14, and the waste heat of the internal pyrolysis reactor 8 can be effectively recovered.

The bottom oil of the evaporation tower 1 heated to around 450° C. is sent to the gas-liquid separation tank 4, where the gas phase is extracted from the top and the liquid phase is extracted from the bottom.

The gas phase portion is fed to the internal thermal decomposition reactor 8 via or without passing through the fixed catalyst tank 7 .

The internal thermal decomposition reactor 8 contains superheated steam STM' (7),
And/or, by partially burning the fuel gas F and oxygen or a gas containing oxygen, a hot gas mainly composed of hydrogen and CO is generated, which is then fed from the top of the gas-liquid separation tank 4 maintained at 450°C or higher. 171oo of gas-phase hydrocarbons
It thermally decomposes instantaneously with a contact time of seconds or less, and is rapidly cooled to 350° C. or lower by circulating oil oR fed into the bottom of the reactor 8.

On the other hand, the liquid phase hydrocarbon extracted from the bottom of the gas-liquid separation tank 4 enters the liquid phase reaction tank 5 or 6 and exits the steam superheating furnace 2.
℃ or higher superheated steam STM is blown from the bottom of the tank to 450℃.
In the above manner, sufficient decomposition is achieved with a residence time of 10 minutes or more and 1 hour or less using the internal heating method.

If a soft pinch product is desired, a short reaction time is required, while if a coke is desired, a long reaction time is required.

In a pinch or when desulfurization in coke is desired, the fuel gas F' is partially combusted in the reactor 11 with oxygen or oxygen-containing gas 0' as shown by the dotted line, and hydrogen, CO
In some cases, a heated mixed gas with a temperature of 1000°C or higher may be introduced.

The decomposed gas phase hydrocarbons leaving the liquid phase reaction tank 5 or 6 may be taken out of the system as is, or as shown in the figure, they are sent to the internal thermal decomposition reactor 8 for third-stage decomposition and further lightening. Sometimes I do.

In this drawing, a plurality of 5 to 6 liquid phase reaction tanks are provided in a switchable type, but a continuous type is also possible.

The features of the present invention are listed below.

(1) Two-stage or three-stage cracking allows light oil and petrochemical raw material olefin gas (C2-C
4) can be obtained.

In other words, the range of application to raw oil and products is wide.

(2) Since the main reaction is an internal heat method, it has good thermal efficiency and serves the purpose of energy saving.

stomach.

(4) Since the contact time is short, there are few side reactions and the product is stable.

(5) When hydrogenating the product, the amount of hydrogen consumed is small.

Further, hydrogen can be self-supplied within the system using by-product gas or coke.

(6) Heat recovery is easy with oil quench.

Next, examples will be shown.

An example will be described in which Daqing crude oil produced in China is used and the main purpose is olefin gas.

Crude oil properties specific gravity '0.855 freezing point
31℃ 2 cups of straw
28.7 wt% Kondrason Carbon 2
．． 7 wt% Distillation properties Initial distillation 71°C 10% 180°C 20% 280°C 25% 300°C Using all the above fractions as raw materials, 10.31 (8,
Two-stage pyrolysis was carried out under a charging condition of 66 kg).

First, it was heated to 250°C to obtain 7.38 kg of prefixed crude oil.

When this was thermally decomposed at 450° C. without cooling in a known pipe-type external heat furnace, a liquid phase product and a gas phase product separated by about 50% were obtained.

The gas phase is 15k superheated steam at 1200℃ without cooling.
g was added and secondary decomposition was carried out at 750°C to obtain the following results.

In the gas phase only, C2 to C4 gas is 20.3% of crude oil,
BTX is 3.0%, ~300℃ (white oil fraction) is 6.35
%, and if you add straight-run oil 14.35% to this, the subtotal is 4.
It becomes 4%.

Furthermore, from the liquid phase (specific gravity 0.911) 3.6851, the fraction below ~300°C is 25%4 due to superheated steam decomposition.
09 gr was obtained.

This is 4.73% based on crude oil, and the total yield of white oil and C2 to C4 gas BTX due to the above secondary cracking in the gas phase is 4.
When 4% is added, a total of 48.73% becomes high value-added products.

Its external 20% A heavy oil and 15% pitch are obtained, 1
Although 5% of fuel gas (mainly composed of methane and hydrogen, ``calorie'' is 6000 Kcal) is obtained, most of it is consumed within the system.

If the conditions for secondary decomposition are lowered to around 600℃, 02~C4
The gas yield was halved, the yield of BTX and ~300°C (white oil) was doubled, and the yield of BTX and ~300°C (white oil) was reduced to 5-6% BTX and ~300°C fraction (white oil).
The yield of white oil is 23-25%.

The following figure summarizes the above yield relationship.

[Brief explanation of drawings]

The drawings illustrate one example of steps suitable for carrying out the invention. 1: Evaporation tower, 2: Steam superheating furnace, 3: Heating furnace, 4: Gas-liquid separation tank, 5, 6: Liquid phase reaction tank, 7 Two fixed catalyst tanks, 8: Internal heating type decomposition reactor, 9: Gas Liquid separation tank, 10: Evaporation tower, 1 Reactor for producing reducing gas, 12 and 13: Heat exchanger, 14:
Waste heat boiler, N, Ninaphtha, STM: Superheated steam (
STM', STM'' (same), F: fuel gas, 0: oxygen or oxygen-containing gas, 0or=heavy raw material oil, OR: circulating oil, W: water.

Claims (1)

[Claims] 1. Mixed group or paraffin group light oil is first heated at 450°C.
Mild thermal decomposition is carried out in an external heating furnace 3 under normal pressure or a pressure of 50 kg/crA or less at the following low temperature, and the product is separated into gas and liquid in a gas-liquid separation tank 4. The phase part is introduced into the internal heat reactor 8 through the catalyst tank 7, and the liquid phase part is introduced into the liquid phase reactor 5 (or 6), and in the internal heat reactor 8 and the liquid phase reactor 5.6, The temperature is raised using only superheated steam, a reducing gas containing hydrogen and carbon monoxide, or a mixture of superheated steam and the above-mentioned reducing gases (hereinafter these gases are collectively referred to as heat carriers) to form a gas phase and a liquid. A method for producing light oil by two-stage thermal decomposition of mixed or paraffin-based heavy oil, characterized in that phase components are subjected to secondary decomposition using an internal thermal method. 2 In the two-stage pyrolysis method described above, liquid phase reaction tank 5 (or 6
), the liquid phase portion is decomposed by the action of the heat transfer medium, and the gas phase portion is guided to the internal heating reactor 8 together with the heat transfer medium for tertiary cracking without cooling, thereby improving the yield of light oil. A method for producing light oil according to claim 1, characterized by three-stage thermal decomposition of paraffinic heavy oil.