CN101955788B

CN101955788B - Fischer-Tropsch synthesis method and system

Info

Publication number: CN101955788B
Application number: CN2010105143709A
Authority: CN
Inventors: 石玉林; 吴秀章; 公磊; 林泉; 吕毅军; 卜亿峰; 王洪学
Original assignee: China Shenhua Coal to Liquid Chemical Co Ltd; Shenhua Group Corp Ltd
Current assignee: China Shenhua Coal to Liquid Chemical Co Ltd; Shenhua Group Corp Ltd
Priority date: 2010-07-09
Filing date: 2010-10-20
Publication date: 2013-05-22
Anticipated expiration: 2030-10-20
Also published as: WO2012003806A1; CN101955788A; RU2562770C2; RU2013102957A; CN101892063A; US20130116348A1

Abstract

The invention relates to a Fischer-Tropsch synthesis method and a system. The method comprises the following steps: a) making CO and H2-containing raw gas enter the first section of a Fischer-Tropsch synthesis reactor to perform Fischer-Tropsch synthesis reaction and obtain the product at the first section of Fischer-Tropsch synthesis reaction; b) separating the product at the first section of Fischer-Tropsch synthesis reaction so as to separate water and unconverted tail gas and obtain a hydrocarbon product and unconverted tail gas of the first section of Fischer-Tropsch synthesis reaction; c) making the unconverted tail gas obtained in the step b) enter the second section of the Fischer-Tropsch synthesis reactor to perform Fischer-Tropsch synthesis reaction and obtain the product at the second section of Fischer-Tropsch synthesis reaction; and d) separating the product at the second section of Fischer-Tropsch synthesis reaction so as to separate water and unconverted tail gas and obtain a hydrocarbon product and unconverted tail gas of the second section of Fischer-Tropsch synthesis reaction, wherein one part of the unconverted tail gas of the second section of Fischer-Tropsch synthesis reaction is returned to the second section of the Fischer-Tropsch synthesis reactor for cyclic reaction. The method and system of the invention simplify the process and are suitable for large-scale industrial production.

Description

A kind of Fischer-Tropsch synthesis method and system

Technical field

The present invention relates to a kind of Fischer-Tropsch synthesis method (Fischer-Tropsch Synthesis) and system, relate in particular to a kind of two stage Fischer-Tropsch synthesis method and system.

Background technology

Along with oil price is constantly soaring in recent years, people more and more pay attention to the technology that Development and Production substitutes oil product, by coal, Sweet natural gas or other material production synthetic gas, the requirement to synthetic gas according to fischer-tropsch synthetic catalyst again, by water-gas shift and purified synthesis gas technique, synthetic gas is processed, take and process rear synthetic gas and synthesize and produce hydro carbons by Fischer-Tropsch as raw material, while by-product oxygenatedchemicals, then adopt ripe Petroleum Processing Technology to be processed, produce high-quality eco-friendly oil product, its core is the Fischer-Tropsch synthetic technology.The Fischer-Tropsch synthesis process that visible exploitation is new, have very important significance to developing alternative oil manufacture technology.

(Gao Jinsheng, Zhang Dexiang write " gelatin liquefaction technology ", Chemical Industry Press, March in 2005 the 1st edition) introduced the Fischer-Tropsch synthesis process of Sasol company maturation, its technical process is single hop technique substantially, the Sasol syrup state bed Fischer Tropsch synthesis technique that the Arge technique that adopts fixed bed, the Kellogg technique that the employing fluidized-bed is arranged and employing slurry state bed are arranged according to the difference of type of reactor, in Sasol I factory, the tail gas of Arge technique is as the raw material of Kellogg technique, there are no the two stage process flow process that adopts same reactor.

Paste state bed reactor is a three-phase bubble column, under moderate temperature, operates, by unstripped gas (gas phase) bubbling in the Fischer-Tropsch synthetic wax (liquid phase) of melting and granules of catalyst (solid phase).Raw material of synthetic gas through preheating enters reactor from reactor bottom, diffuses in the slurry be comprised of the liquid wax generated and granules of catalyst.In the process risen at bubble, Fischer-Tropsch synthesis constantly occurs in synthetic gas, generates more Fischer-Tropsch synthetic wax.The heat that reaction produces is produced steam by built-in cooling coil pipe and is taken out.Wax product is by being separated and the extraction device in the strainer built-in in reactor slurry reactor district, or adopts after extracting slurries out and by external equipment for separating liquid from solid, the method for Fischer-Tropsch synthetic wax and catalyst solid particle separation is obtained.From reactor top tail gas out cooling recyclable light component and water.The product a refining unit of the hydrocarbon product fed downstream obtained, water is sent to retrieving arrangement and processes.

The paste state bed reactor reactant mixes, has good heat transfer property, is conducive to the control of temperature of reaction and shifting out of reaction heat, but isothermal operation, thus available higher average operation temperature and obtain higher speed of reaction; Control simply, running cost is low; By regular replacement catalyzer, the average catalyst life-span is easy to control; Be easier to the selectivity of control process, improve the quality of thick product.Therefore, syrup state bed Fischer Tropsch synthesizes in the situation that take and produce synthetic wax and diesel oil as main superiority is obvious, becomes Fischer-Tropsch synthetic technology development trend.

Paste state bed reactor be designed with its uniqueness, in order to keep the slurry bed characteristic, at first be that catalyzer is manufactured to tiny particle so that can be suspended in liquid phase region, it two is in the interval operation of specific temperature of reaction so that the Fischer-Tropsch synthetic wax that reaction generates exists with liquid form and provides outside slurry state condition, in addition, still need and will operate with certain gas flow rate (empty tower gas velocity), both avoid causing because gas flow rate is little granules of catalyst deposition, and avoided again gas flow rate too high and granules of catalyst is carried out to reactor.Therefore, when needs increase Fischer-Tropsch synthesizer throughput, while increasing Fischer-Tropsch synthesis material gas flow, usually need to improve reactor diameter to maintain the empty tower gas velocity needed.

But, when improving device, needs produce the Fischer-Tropsch synthesis oil ability while reaching more than 500,000 ton/years scale, due to restrictions such as reactor manufacturing process, transport conditions, under level, the diameter maximum of reactor only can reach 10 meters left and right at present, therefore needs the paste state bed reactor more than at least two to be processed.The megaton Fischer-Tropsch synthesizer of suitability for industrialized production is designed to the conventional separate unit paste state bed reactor Fischer-Tropsch synthesis process device parallel operation that two covers are complete at present.Every reactor head product all arranges oil-water-gas separating system, and most of circulation of tail gas returns reactor separately, to obtain the total efficiency of carbon conversion needed, the emptying of small part tail gas.

China Patent Publication No. CN1611565 (application number CN200310108146.X) discloses a kind of technique of producing liquid fuel with synthetic gas, and this processing method comprises Fischer-Tropsch synthesis unit, C ₃-C ₅recovery unit, three parts of refinery unit.Wherein the Fischer-Tropsch synthesis unit is divided into two-stage, and product is paraffin and condensation product; Two-stage Fischer-Tropsch synthesizer carries out respectively the partial tail gas circulation; The residual exhaust of first step Fischer-Tropsch synthetic gas enters second stage Fischer-Tropsch synthesizer as unstripped gas; The residual exhaust of second stage Fischer-Tropsch synthesizer enters into C ₃-C ₅recovery unit.C ₃-C ₅recovery unit is the method cooling by the degree of depth, reclaims the C of the overwhelming majority in tail gas ₃above component, these components enter with the paraffin of two-stage Fischer-Tropsch synthesis unit production the production that refinery unit is carried out liquid fuel together with condensation product.This process using dual stage apparatus Fischer-Tropsch is synthetic, can, by reducing the method for single-stage CO transformation efficiency, reduce CH ₄productive rate.But the partial tail gas of this technique first step Fischer-Tropsch synthesizer circulates, increased the investment of recycle compressor system and process cost, reduced the economy of whole technique.In addition, first step Fischer-Tropsch synthesizer has adopted the partial tail gas circulation, has reduced the load of reactor processing fresh synthesis gas raw material, has reduced oily yield.

China Patent Publication No. CN1948438 (application number CN200610140020.4) has introduced a kind of Fischer-Tropsch synthesis method, comprise the following steps: a) make raw material of synthetic gas enter first paragraph Fischer-Tropsch synthesis device, carry out Fischer-Tropsch synthesis under the effect of catalyzer; B) separate first paragraph Fischer-Tropsch synthesis product, partial tail gas returns to first paragraph Fischer-Tropsch synthesis device circulating reaction, then by all the other tail gas, contain C1～the C4 hydrocarbon conversion is synthetic gas; C) will be from step b) conversion after tail gas with the recycled offgas of second segment Fischer-Tropsch synthesis, mix, enter second segment Fischer-Tropsch synthesis device, carry out Fischer-Tropsch synthesis under the effect of catalyzer; D) separate second segment Fischer-Tropsch synthesis product, most of tail gas returns to second segment Fischer-Tropsch synthesis device circulating reaction, discharges remaining tail gas.The method has adopted the gas circulation flow process at first paragraph, is provided with gas circulating compressor, has reduced the ability of reactor processing fresh synthesis gas, and tail gas need adopt the natural gas auto-thermal oxidation process for preparing synthetic gas by C while entering second segment ₁～C ₄lighter hydrocarbons are converted into synthetic gas, have increased equipment cost.

China Patent Publication No. CN100575457C (patent No. ZL200610140019.1) has introduced a kind of Fischer-Tropsch synthesis method, comprise the following steps: (1) makes the producing synthesis gas from coal raw material enter first step Fischer-Tropsch synthesis device, contact with ferrum-based catalyst, and reacted under the Fischer-Tropsch synthesis condition; (2) separate the first order reaction product, after reaction, remaining tail gas removes CO ₂after, enter C1-C4 hydrocarbon conversion device to produce CO and H ₂, the tail gas after then making to transform enters second stage Fischer-Tropsch synthesis device, contacts with cobalt-base catalyst, and is reacted under the Fischer-Tropsch synthesis condition; (3) separate the second order reaction product, discharge section tail gas, remaining tail gas returns to first step Fischer-Tropsch synthesis device and recycles.The method first step reactor has adopted slurry state bed, and the circulation of tail gas gas that the part feed gas is second stage reaction is arranged, and second stage reaction adopts cobalt-base catalyst, although space-time yield is higher, but because reactor is fixed bed, the more difficult control of reaction heat-obtaining, and fixed-bed process is difficult to large-scale application.

Summary of the invention

The object of the present invention is to provide a kind of mould Fischer-Tropsch synthesis method and system, especially two stage Fischer-Tropsch synthesis method and system.

One aspect of the present invention relates to a kind of Fischer-Tropsch synthesis method, comprises the following steps:

A) first paragraph Fischer-Tropsch synthesis

Make to contain CO and H ₂unstripped gas enter first paragraph Fischer-Tropsch synthesis device, carry out Fischer-Tropsch synthesis under the effect of catalyzer, obtain first paragraph Fischer-Tropsch synthesis product;

B) separation of first paragraph Fischer-Tropsch synthesis product

First paragraph Fischer-Tropsch synthesis product is separated, water is separated with unconverted tail gas, obtained the unconverted tail gas of hydrocarbon product, first paragraph Fischer-Tropsch synthesis;

C) second segment Fischer-Tropsch synthesis

By step b) in the unconverted tail gas that obtains enter second segment Fischer-Tropsch synthesis device, carry out Fischer-Tropsch synthesis under the effect of catalyzer, obtain second segment Fischer-Tropsch synthesis product;

D) separation of second segment Fischer-Tropsch synthesis product

Second segment Fischer-Tropsch synthesis product is separated, water is separated with unconverted tail gas, obtain the unconverted tail gas of hydrocarbon product, second segment Fischer-Tropsch synthesis, the part of the unconverted tail gas of second segment Fischer-Tropsch synthesis is returned to second segment Fischer-Tropsch synthesis device circulating reaction.

The present invention relate on the other hand the Fischer-Tropsch synthesis system, comprising:

A) first paragraph Fischer-Tropsch synthesis device, wherein accommodate fischer-tropsch synthetic catalyst, and first paragraph Fischer-Tropsch synthesis device at least has:

The first paragraph reactor inlet, be positioned at the bottom of first paragraph Fischer-Tropsch synthesis device;

The first paragraph reactor head exports, and is positioned at the top of first paragraph Fischer-Tropsch synthesis device;

First paragraph Fischer-Tropsch synthetic wax or slurries export, and are positioned at the Jiang Taichuan district of first paragraph Fischer-Tropsch synthesis device;

B) first paragraph separation system, separated for the top product to from the outlet of first paragraph reactor head, and water is separated with unconverted tail gas, obtains the unconverted tail gas of hydrocarbon product, first paragraph Fischer-Tropsch synthesis; The first paragraph separation system has:

First paragraph separation system entrance, be connected with the outlet of first paragraph reactor head;

A plurality of first paragraph separation system outlet comprise:

The outlet of first paragraph hydrocarbon product, and

Tail gas outlet that first paragraph is unconverted;

C) second segment Fischer-Tropsch synthesis device, wherein accommodate fischer-tropsch synthetic catalyst, and second segment Fischer-Tropsch synthesis device at least has:

The second segment reactor inlet, be positioned at the bottom of second segment Fischer-Tropsch synthesis device, and be connected with the unconverted tail gas outlet of first paragraph;

The second segment reactor head exports, and is positioned at the top of second segment Fischer-Tropsch synthesis device;

Second segment Fischer-Tropsch synthetic wax or slurries export, and are positioned at the Jiang Taichuan district of second segment Fischer-Tropsch synthesis device;

D) second segment separation system, separated for the top product to from the outlet of second segment reactor head, and water is separated with unconverted tail gas, obtains the unconverted tail gas of hydrocarbon product, second segment Fischer-Tropsch synthesis, and the second segment separation system has:

Second segment separation system entrance, be connected with the outlet of second segment reactor head;

A plurality of second segment separation system outlet comprise:

The outlet of second segment hydrocarbon product, and

Tail gas outlet that second segment is unconverted.

Method and system of the present invention has overcome the facility investment existed when conventional Fischer-Tropsch synthesis method is produced liquid product and the shortcoming that process cost is high, space-time yield is low, the CO utilization ratio is low, has simplified technical process, and has been suitable for large-scale industrial production.

The accompanying drawing explanation

The schema that Fig. 1 is the extensive Fischer-Tropsch synthesis process of two-part of the present invention.

Embodiment

The present invention is dependent on the understanding of Fischer-Tropsch synthesis (especially Fe-series catalyst Fischer-Tropsch synthesis) basic characteristics is carried out.

During the Fe-series catalyst Fischer-Tropsch synthesis, main reaction has two classes:

CO+H ₂→ HC (hydrocarbon)+H ₂o (1)

Wherein Equations of The Second Kind reaction (2) is water gas shift reaction (WGS reaction), and it is a reversible reaction, and its CO conversion occurred accounts for 15～35% of total carbon conversion.

Obviously, improve the production capacity of Fischer-Tropsch synthesis speed, increase device Fischer-Tropsch synthesis oil, and the method for raising CO utilization ratio is to improve the effective synthetic gas (CO+H of reactor inlet ₂) flow (maintaining under specific empty tower gas velocity and can meaning by the dividing potential drop of effective synthetic gas), and reduce WGS forward reaction speed.From the WGS reaction characteristics, can find out, reduce WGS forward reaction speed, the effective means that improves the utilization ratio of CO has two: the H in a. minimizing system ₂the O dividing potential drop; B. CO in the raising system ₂dividing potential drop.

On the other hand, owing to there being Equations of The Second Kind WGS reaction on Fe-series catalyst, therefore the water partial pressure in the reduction system is conducive to reduce WGS forward reaction speed, has relatively increased the CO reactant concn that first kind Fischer-Tropsch synthesis is converted into hydrocarbon, is conducive to improve Fischer-Tropsch synthesis speed.

The inventor finds, when reactor carries out subsection setup, while in the middle of section, carrying out gas-phase dehydration, can improve Fischer-Tropsch synthesis speed, increases device capbility.

When cobalt-base catalyst exists, although the WGS reaction occurs hardly, the existence of the water of Fischer-Tropsch synthesis production can affect Fischer-Tropsch synthesis speed equally.

According to the understanding to the Fischer-Tropsch synthesis performance and test, the present invention has been proposed.

In the present invention, " with ... be connected " or " being connected to ", can be both that the two directly is connected, also can be connected or connect across common parts or device (such as valve, pump, interchanger etc.).

In the present invention, in reconcilable situation, all embodiment of the present invention, embodiment and feature can combine mutually.

The present invention relates to a kind of Fischer-Tropsch synthesis method, comprise the following steps:

A) first paragraph Fischer-Tropsch synthesis

B) separation of first paragraph Fischer-Tropsch synthesis product

C) second segment Fischer-Tropsch synthesis

D) separation of second segment Fischer-Tropsch synthesis product

Preferably, the unconverted tail gas of first paragraph Fischer-Tropsch synthesis does not return to first paragraph Fischer-Tropsch synthesis device circulating reaction.

Preferably, step a) in, fresh synthesis gas as the unstripped gas one way by first paragraph Fischer-Tropsch synthesis device.

Preferably, control in first paragraph Fischer-Tropsch synthesis device the CO transformation efficiency at 30%-70%, more preferably 40%～65%, further preferably 50%～60%.

Preferably, in unstripped gas, water-content is lower than 0.05%, preferably lower than 0.01%, more preferably less than 0.005%, most preferably lower than 0.0001% (volume ratio).

Preferably, enter the unconverted tail gas water-content of second segment Fischer-Tropsch synthesis device lower than 0.05%, preferably lower than 0.01%, more preferably less than 0.005%, most preferably lower than 0.0001% (volume ratio).

Preferably, preferably control in first paragraph Fischer-Tropsch synthesis device the CO transformation efficiency 30%～70%, more preferably 40%～65%, further preferably 50%～60%.

Step b) with steps d) in separate and comprise: the oil-water of Fischer-Tropsch synthesis top product-gas separates.Preferably, b) oil-water of first paragraph Fischer-Tropsch synthesis top product-gas separates and/or d) oil-water of second segment Fischer-Tropsch synthesis top product-gas separates and comprises the following steps:

At first, adopt high pressure hot separator (being called for short " hot high score ") to carry out flash separation, obtain high pressure hot separator liquid, high pressure hot separator gas;

Then, adopt cold high pressure separator (being called for short " cold high score ") to carry out flash separation high pressure hot separator gas, obtain two-phase: the blended liquid phase product that cold high pressure separator liquid is light ends oil and water, cold high pressure separator gas is unconverted tail gas.

Preferably, high pressure hot separator, under 120～220 ℃, preferably moves under 140～180 ℃.Preferably, cold high pressure separator, under 5～60 ℃, more preferably moves under 10～50 ℃.

Preferably, method of the present invention further comprises:

E) the high pressure hot separator liquid of first paragraph, second segment Fischer-Tropsch synthesis is passed into to thermal low-pressure separators (being called for short " low minute of heat "), flash separation obtains heavy ends oil production and thermal low-pressure separators gas again; And alternatively

F) the blended liquid phase product of the cold high pressure separator of first paragraph, second segment Fischer-Tropsch synthesis (being called for short " cold high score ") and optional thermal low-pressure separators gas are passed into to cold low separator (being called for short " cold low minute "), flash separation obtains cold low separator gas, light ends oil production, water.

Thermal low-pressure separators can 60～200 ℃, preferably 70～180 ℃, more preferably 80～160 ℃, most preferably carry out under 90～140 ℃.Cold low separator (cold low minute) can 5～60 ℃, preferably carry out under 20～50 ℃.

Preferably, step a) in the first paragraph Fischer-Tropsch synthesis under following reaction conditions, carry out.

Preferably, for step a) in the first paragraph Fischer-Tropsch synthesis, temperature of reaction is 200～320 ℃, is preferably 235～275 ℃, more preferably 245～265 ℃.

Preferably, for step a) in the first paragraph Fischer-Tropsch synthesis, reaction pressure is 15～50bar, is preferably 20～40bar, more preferably 25～35bar.

Preferably, for step a) in the first paragraph Fischer-Tropsch synthesis, reactor inlet gas empty tower gas velocity is 10～40cm/s, is preferably 15～35cm/s, more preferably 15～25cm/s.

Preferably, for step a) in the first paragraph Fischer-Tropsch synthesis, the volumetric flow rate of unstripped gas (reactor inlet gas) is 2000～50000Nml/g-cat./h with the ratio of catalyst quality (i.e. gas agent ratio), be preferably 5000～30000Nml/g-cat./h, more preferably 8000～20000Nml/g-cat./h.

Preferably, step c), the second segment Fischer-Tropsch synthesis carries out under following reaction conditions.

Preferably, for step a) in the second segment Fischer-Tropsch synthesis, temperature of reaction is 200～320 ℃, is preferably 235～275 ℃, more preferably 245～265 ℃.

Preferably, for step a) in the second segment Fischer-Tropsch synthesis, reaction pressure is 15～50bar, is preferably 18～38bar, more preferably 25～35bar.

Preferably, for step a) in the second segment Fischer-Tropsch synthesis, the reactor inlet empty tower gas velocity is 10～40cm/s, is preferably 15～35cm/s, more preferably 15～25cm/s.

Preferably, for step a) in the second segment Fischer-Tropsch synthesis, the volume ratio of reactor inlet gas flow and catalyzer (i.e. gas agent ratio) is 2000～50000Nml/g-cat./h, is preferably 5000～30000Nml/g-cat./h, more preferably 8000～20000Nml/g-cat./h.

Preferably, for step a) in the first paragraph Fischer-Tropsch synthesis, CO and H in unstripped gas ₂volume ratio be 0.67～2.2, preferably 0.8～2, more preferably 1～2, most preferably 1.4～2.

Preferably, step a) Raw gas is synthetic gas, preferably the synthetic gas of process purification and water-gas shift.Preferably using fresh synthesis gas as unstripped gas.

Preferably, step a) and c) in the catalyzer that uses be Fe-series catalyst or cobalt series catalyst.Preferably, when adopting Fe-series catalyst, the H of unstripped gas ₂with the volume ratio of CO for being 1.4～1.8, preferably 1.4～1.7, more preferably 1.5～1.7, most preferably 1.5～1.6.Preferably, when adopting cobalt series catalyst, the H of unstripped gas ₂with the volume ratio of CO be 1.8～2.2, preferably 1.9～2.1, more preferably 1.95～2.05, most preferably 2.0.

Preferably, the number of first paragraph Fischer-Tropsch synthesis device equals or, more than second segment Fischer-Tropsch synthesis device number, more preferably the number of first paragraph Fischer-Tropsch synthesis device is more than second segment Fischer-Tropsch synthesis device number.The number of the number of first paragraph Fischer-Tropsch synthesis device or first paragraph Fischer-Tropsch synthesis device is during more than 1 (that is, more than 2), and the Fischer-Tropsch synthesis device of this section is in parallel.

Preferably, first paragraph Fischer-Tropsch synthesis device and second segment Fischer-Tropsch synthesis device are paste state bed reactor.Preferably first paragraph Fischer-Tropsch synthesis device is one or a plurality of paste state bed reactors in parallel, and second segment Fischer-Tropsch synthesis device is a paste state bed reactor.The Fischer-Tropsch synthesis device can also be fixed bed, fixed fluidized bed, fluidized-bed.

Preferably, the unconverted tail gas of second segment Fischer-Tropsch synthesis mixes with the unconverted tail gas of whole first paragraph Fischer-Tropsch synthesis, then enters second segment Fischer-Tropsch synthesis device.Preferably the unconverted tail gas of second segment Fischer-Tropsch synthesis is 0.5～5 with the unconverted tail gas mixed volume ratio of first paragraph Fischer-Tropsch synthesis, is preferably 1～3, more preferably 1.5～2.5.Preferably, before mixing, remove the CO in the unconverted tail gas of second segment Fischer-Tropsch synthesis ₂.For example, remove CO ₂adopt hot salt of wormwood to take off CO ₂method or WATER-WASHING METHOD are carried out.

Preferably, step b) in, the reactor head product enters high pressure hot separator (for example, under 120～220 ℃, being preferably 140～180 ℃), carries out flash separation and goes out gas phase and heavy oil phase.Gaseous stream enters cold high pressure separator (for example, under 5～60 ℃, being preferably 10～50 ℃), and flash separation again obtains the blended liquid phase product of gas, light ends oil and synthetic water.

Preferably, steps d) in, the reactor head product enters high pressure hot separator (for example, under 120～220 ℃, being preferably 140～180 ℃), carries out flash separation and obtains gas phase and heavy oil phase.Gaseous stream enters cold high pressure separator (for example, under 5～60 ℃, being preferably 10～50 ℃), and flash separation again obtains the blended liquid phase product of gas, light ends oil and synthetic water.

The quantity discharged of tail gas CO+H in tail gas ₂content determine, to guarantee CO+H in tail gas ₂content be not less than 40%, CO+H in tail gas ₂content higher than 50%, reduce quantity discharged; CO+H in tail gas ₂content lower than 40%, increase quantity discharged.

The present invention relates to the Fischer-Tropsch synthesis system on the other hand, comprising:

A) first paragraph Fischer-Tropsch synthesis device, wherein accommodate fischer-tropsch synthetic catalyst, and first paragraph Fischer-Tropsch synthesis utensil has:

B) first paragraph separation system, separated for the top product to from the outlet of first paragraph reactor head, and water is separated with unconverted tail gas, obtains the unconverted tail gas of hydrocarbon product, first paragraph Fischer-Tropsch synthesis, and the first paragraph separation system has:

A plurality of first paragraph separation system outlet comprise:

The outlet of first paragraph hydrocarbon product, and

Tail gas outlet that first paragraph is unconverted;

C) second segment Fischer-Tropsch synthesis device, wherein accommodate fischer-tropsch synthetic catalyst, and second segment Fischer-Tropsch synthesis utensil has:

The second segment reactor inlet, be positioned at the bottom of second segment Fischer-Tropsch synthesis device,

And be connected with the unconverted tail gas outlet of first paragraph;

The second segment reactor head exports, and is positioned at the top of second segment Fischer-Tropsch synthesis device 102;

A plurality of second segment separation system outlet comprise:

The outlet of second segment hydrocarbon product, and

Tail gas outlet that second segment is unconverted.

Preferably, the unconverted tail gas outlet of first paragraph does not connect the first paragraph reactor inlet.

Preferably, B) first paragraph separation system and/or D) the second segment separation system comprises oil-water-air separation.

Preferably, B) first paragraph separation system and/or D) oil-water-gas separating system of second segment separation system comprises:

High pressure hot separator has:

The high pressure hot separator entrance, be connected with first paragraph separation system entrance or second segment separation system entrance,

The high pressure hot separator liquid exit, and

The high pressure hot separator pneumatic outlet;

Cold high pressure separator has:

The cold high pressure separator entrance, be connected with the high pressure hot separator pneumatic outlet,

The cold high pressure separator liquid exit, and

The cold high pressure separator pneumatic outlet.

Preferably, Fischer-Tropsch synthesis system of the present invention further comprises:

Thermal low-pressure separators has:

The thermal low-pressure separators entrance, be connected with the high pressure hot separator liquid exit of first paragraph separation system and/or second segment separation system,

The thermal low-pressure separators pneumatic outlet,

The thermal low-pressure separators liquid exit;

Alternatively, the cold low separator has:

The cold low separator inlet, be connected to thermal low-pressure separators liquid exit and/or the outlet of cold high pressure separator product liquid,

The outlet of cold low separator gas,

The light ends oil export,

The outlet of Fischer-Tropsch synthetic water.

Preferably, Fischer-Tropsch synthesis system of the present invention further takes off CO ₂system, de-CO ₂system has:

De-CO ₂colvent inlet,

De-CO ₂solvent outlet,

De-CO ₂the system gas entrance, be connected with the cold high pressure separator pneumatic outlet,

De-CO ₂the system gas outlet, be connected with the second segment reactor inlet.

Preferably, first paragraph Fischer-Tropsch synthesis device and one of second segment Fischer-Tropsch synthesis device or a plurality of paste state bed reactors in parallel; Preferably, first paragraph Fischer-Tropsch synthesis device is one or a plurality of paste state bed reactors in parallel, and second segment Fischer-Tropsch synthesis device is a paste state bed reactor.

Preferably, the number of first paragraph Fischer-Tropsch synthesis device is more than or equal to the number of second segment Fischer-Tropsch synthesis device, is preferably greater than the number of second segment Fischer-Tropsch synthesis device.

Preferably, Fischer-Tropsch synthesis system of the present invention further comprises: wax filter is arranged on inside or the outside of first paragraph Fischer-Tropsch synthesis device and second segment Fischer-Tropsch synthesis device.

Preferably, Fischer-Tropsch synthesis system of the present invention further comprises: the outlet of Fischer-Tropsch synthetic wax is arranged on first paragraph Fischer-Tropsch synthesis device and Jiang Tai district, second segment Fischer-Tropsch synthesis device middle part.

Preferred method and system of the present invention is two stage Fischer-Tropsch synthesis method and system.

Simply being described as of technique of the present invention, during megaton large-scale industry gasifying device, because it needs two above reactors, fresh synthesis material gas is that one way is passed through first paragraph Fischer-Tropsch synthesis device, first paragraph Fischer-Tropsch synthesis device top product separates through oil-water-gas, the unconverted tail gas obtained enters second segment Fischer-Tropsch synthesis device, second segment Fischer-Tropsch synthesis device top exit product is again after oil-water-gas separates, most of circulation of tail gas returns second segment Fischer-Tropsch synthesis device, to obtain the CO total conversion rate required.This process unit height is integrated, the liquid product that the high pressure hot separator of two-stage reaction obtains all enters same thermal low-pressure separators to carry out flash separation again and obtains heavy distillate, and the cold high pressure separator product liquid light ends of two-stage reaction oil all flow into same cold low separator with the synthetic water mixture and separated, obtain the oily and Fischer-Tropsch synthetic water product of light ends.

A kind of preferred embodiment in, the extensive Fischer-Tropsch synthesis method of two-part provided by the invention comprises the following steps:

A) make fresh synthesis gas unstripped gas enter first paragraph Fischer-Tropsch synthesis device, carry out Fischer-Tropsch synthesis under the effect of catalyzer;

B) first paragraph Fischer-Tropsch synthesis device top product adopts high pressure hot separator and cold high pressure separator flash separation to obtain the first paragraph Fischer-Tropsch synthesis products such as the blended liquid phase of heavy oil phase, lightweight oil and synthetic water, unconverted tail gas in succession;

C) gas of the synthetic cold high pressure separator of first paragraph Fischer-Tropsch is mixed with the recycled offgas of second segment Fischer-Tropsch synthesis, enter second segment Fischer-Tropsch synthesis device, carry out Fischer-Tropsch synthesis under the effect of catalyzer;

D) in succession adopt high pressure hot separator and cold high pressure separator flash separation second segment Fischer-Tropsch synthesis product, obtain blended liquid phase, tail gas of heavy oil phase, lightweight oil and synthetic water etc., most of tail gas returns to second segment Fischer-Tropsch synthesis device circulating reaction, discharges remaining tail gas;

E) first paragraph, the synthetic high pressure hot separator liquid of second segment Fischer-Tropsch are passed into to a thermal low-pressure separators simultaneously, flash separation obtains the heavy ends oil production again;

F) the blended liquid phase product of first paragraph, the synthetic cold high pressure separator of second segment Fischer-Tropsch is passed into to a cold low separator simultaneously, flash separation obtains light ends oil, synthetic water product again.

Below further describe two stage Fischer-Tropsch synthesis method of the present invention, but the present invention is not therefore subject to any restriction.

In above-mentioned Fischer-Tropsch synthesis method, the fresh synthesis gas of step in a) can be produced by coal, Sweet natural gas or organism, but must remove the material to the toxic effect of fischer-tropsch synthetic catalyst such as its contained sulphur through purifying." gelatin liquefaction technology " (Chemical Industry Press, author: Gao Jinsheng, Zhang Dexiang, publication time: in March, 2005) described the correlation technique for preparing synthetic gas, purified synthesis gas and conversion in detail.H in fresh synthesis gas ₂with the volume ratio of CO be 0.67～2.2, preferably 0.8～2, more preferably 1～2, most preferably 1.4～2.

Step a) middle first paragraph Fischer-Tropsch synthesis is carried out under following reactant condition: temperature of reaction is 200～320 ℃, is preferably 235～275 ℃; Reaction pressure is 15～50bar, is preferably 20～40bar; Make reactor inlet gas empty tower gas velocity reach 10～40cm/s, be preferably 15～35cm/s; The volume ratio of fresh synthesis gas raw material and catalyzer is 2000～50000, is preferably 5000～30000.The invention belongs to the low temperature Fischer-Tropsch synthesis.

Step b) in, the reactor head product enters high pressure hot separator, under 120～220 ℃, is preferably 140～180 ℃, carries out flash separation and goes out gas phase (high pressure hot separator gas) and heavy oil phase (high pressure hot separator liquid).Gaseous stream enters cold high pressure separator, under 5～60 ℃, is preferably 10～50 ℃, and flash separation again obtains the blended liquid phase product (cold high pressure separator liquid) of gas, light ends oil and synthetic water.

Step c) in, the recycled offgas of second segment Fischer-Tropsch synthesis with from step b) synthetic conversion of first paragraph Fischer-Tropsch after cold high pressure separator gas with volume ratio (recycle ratio) with 0.5～5, be preferably 1～3 and mix, enter second segment Fischer-Tropsch synthesis device.The second segment Fischer-Tropsch synthesis carries out under following reaction conditions: temperature of reaction is 200～320 ℃, is preferably 235～275 ℃; Reaction pressure is 15～50bar, is preferably 18～38bar; The reactor inlet empty tower gas velocity is 10～40cm/s, is preferably 15～35cm/s; The volume ratio of reactor inlet gas flow and catalyzer is 2000～50000, is preferably 5000～30000.

Steps d) in, the reactor head product enters high pressure hot separator, under 120～220 ℃, is preferably 140～180 ℃, carries out flash separation and obtains gas phase (high pressure hot separator gas) and heavy oil phase (high pressure hot separator liquid).Gaseous stream enters cold high pressure separator, under 5～60 ℃, is preferably 10～50 ℃, and flash separation again obtains cold high pressure separator gas, cold high pressure separator liquid (the blended liquid phase product of light ends oil and synthetic water).Cold high pressure separator gas major part loops back reactor, and part is as exhaust emissions.The quantity discharged of tail gas is looked CO+H in gas ₂content and determine common CO+H ₂content be not less than 40%, be preferably and be not less than 50%.The gas of circulation Returning reactor is synthesizing before cold high pressure separator gas mixes and is being removed CO with the first paragraph Fischer-Tropsch ₂.Remove the CO in circulation gas ₂method can adopt the commonly used CO that removes ₂processing method, for example, hot salt of wormwood takes off CO ₂method or WATER-WASHING METHOD.Hot salt of wormwood takes off CO ₂method device commonly used is the de-CO of hot salt of wormwood ₂adsorption tower, the saleratus of generation removes CO at regenerator column ₂, the solution of potassium carbonate obtained returns to adsorption tower.WATER-WASHING METHOD only need be established water washing tank and be got final product.

The severity of this technology controlling and process first paragraph Fischer-Tropsch synthesis process condition, make the synthetic CO transformation efficiency of first paragraph Fischer-Tropsch between 35%～70%, be preferably 40%～65%, guarantee the space-time yield of catalyzer, reduce the severity of second segment Fischer-Tropsch synthesis process condition, make the per pass conversion of the synthetic CO of second segment Fischer-Tropsch lower than 50%, guarantee that the productive rate of methane of whole technique is low, the oil product yield is high.The synthetic compound rear CO total conversion rate of first paragraph and second segment Fischer-Tropsch reaches more than 90%.

Step a) and c) in the Fischer-Tropsch synthesis device adopt paste state bed reactor.The synthetic reactor of first paragraph Fischer-Tropsch can be one or more paste state bed reactors, and second segment is only established a paste state bed reactor.

Step a) and step c) in the catalyzer that uses can be iron system or cobalt system slurry state bed catalyst.During Fe-series catalyst, the H of fresh synthesis gas ₂with the volume ratio of CO for being preferably 1.4～1.8.During cobalt series catalyst, the H of fresh synthesis gas ₂with the volume ratio of CO for being preferably 2.0.Process natural gas base synthetic gas should adopt cobalt series catalyst, and the processing coal based synthetic gas should adopt Fe-series catalyst.

The main products (hydrocarbon product) that Fischer-Tropsch synthesizer of the present invention is produced is hydrocarbon gas (containing low-carbon alkene), light naphthar and heavy naphtha, diesel oil distillate, wax and synthetic water, especially with petroleum naphtha, diesel oil distillate and wax primary product.

The wax of producing in the Fischer-Tropsch synthesis device by after the strainer that arranges in reactor and catalyst separating as the product discharge, also can by the slurries in the extraction device by external equipment for separating liquid from solid with obtain after granules of catalyst is separated.In the external filter situation, separate the granules of catalyst obtained and again loop back the reaction of reactor sustainable participation.

Compared with prior art, two stage Fischer-Tropsch synthesis method provided by the present invention has following beneficial effect:

A. compared with the prior art two-stage process of the present invention has reduced the synthetic recycle gas compressor system of first paragraph Fischer-Tropsch, has reduced facility investment and relating operation expense.

B. at first paragraph:

(1) total conversion rate (namely per pass conversion) is moderate, and it is more reasonable that product distributes, and methane selectively is low;

(2) reactor inlet gas is all fresh synthesis gas, dry moisture-free, and the synthetic CO total conversion rate of first paragraph Fischer-Tropsch is controlled between 35%～75%, so in reactor, gas phase steam dividing potential drop reaches the situation more than 90% lower than CO total conversion rate under state in parallel, WGS speed of reaction state during lower than parallel connection, CO ₂production declining, elective reduction;

(3) the effective gas dividing potential drop of reactor inlet reaches 100%, under the paste state bed reactor condition, under the fresh synthesis gas high-speed, operates to greatest extent, is very beneficial for Fischer-Tropsch synthesis, obtains to greatest extent space-time yield.

C. at second segment:

(1) the synthetic cold high pressure separator gas of first paragraph Fischer-Tropsch is as the fresh synthesis gas charging of second segment, be equivalent in multiple process the separate unit reactor process and be reacted to a half and carried out the vapor condensation dehydration, while can be regarded as gas phase water partial pressure in second segment Fischer-Tropsch synthesis device lower than the separate unit reactor, the CO total conversion rate reaches 65% above reactive moieties (second half section of the reactor in the time of can regarding as multiple process separate unit reactor process).Therefore, be conducive to improve Fischer-Tropsch synthesis speed;

(2) because be that the stack transformation efficiency reaches more than 90% on first paragraph Fischer-Tropsch synthesis device, thus the second segment Fischer-Tropsch synthetic during with respect to parallel connection per pass conversion can hang down certain operations, product distributes and also can improve.

The present invention passes through first paragraph Fischer-Tropsch synthesis device by fresh synthesis gas high-speed one way, then enter second segment Fischer-Tropsch synthesis device after gaseous stream condensation dehydration, the severity of Reasonable Regulation And Control two-stage process parameter, can be in the situation that save a recycle gas compressor, greatly reduce the cycle compressor process cost, improve the unit space-time yield of catalyzer, reduce the productive rate of methane, realize that whole technical process is short, it is low to invest, operation energy consumption is little, and the purpose of greater catalytic agent space-time yield, low methane production.

Below in conjunction with accompanying drawing, method provided by the present invention is further described, but the present invention is not therefore subject to any restriction.For outstanding process thought of the present invention, the equipment of many necessity while having omitted industrial application in figure, as process furnace, pump, valve and interchanger etc.

As shown in Figure 1, through purifying and adjust CO and H ₂(for example, volume ratio is 0.67～2.2) fresh synthesis gas raw material 1 through interchanger 105 and 103 and the Fischer-Tropsch synthetic heat exchange after, enter first paragraph Fischer-Tropsch synthesis device 102, under the effect of fischer-tropsch synthetic catalyst, Fischer-Tropsch synthesis occurs, because Fischer-Tropsch synthesis is strong exothermal reaction, adopt steam coils that reaction heat is taken out, the temperature of whole reactor is by the pressure-controlling of steam pockets 101, by-product water vapor 26, the wax generated is by built-in strainer and the catalyst separating of reactor, obtain product wax 13, the mixture of the lighting end of reacted unstripped gas and part Fischer-Tropsch synthetic (, top product) 2 tops from reactor 102 out, carry out gas-liquid separation at high pressure hot separator 104 with unstripped gas after interchanger 103 heat exchange, isolate high pressure hot separator liquid (high pressure hot separator liquid product) 11 and high pressure hot separator gas 3, high pressure hot separator gas 3 again with the unstripped gas heat exchange after, fall within the range of 50 ℃ of left and right, carry out gas-liquid separation at cold high pressure separator 106, isolate cold high pressure separator gas (unconverted tail gas) 4 and cold high pressure separator liquid (the blended liquid phase product of light ends oil and water) 6.The cold high pressure separator gas 4 of discharging from cold high pressure separator 106 tops mixes with second segment recycled offgas 35, gas mixture 40 boosts through recycle gas compressor, after second segment interchanger 115 and interchanger 113 and 33 heat exchange of second segment Fischer-Tropsch synthesis device top product, enter second segment Fischer-Tropsch synthesis device 112 and carry out the synthetic conversion of Fischer-Tropsch.The same with first paragraph Fischer-Tropsch synthesis device 102, the temperature of reaction of second segment Fischer-Tropsch synthesis device 112 is controlled by steam pockets 111, by-product water vapor 25, synthetic wax strainer and the catalyst separating built-in through reactor generated of second segment Fischer-Tropsch, obtain Fischer-Tropsch synthetic wax 43, its with obtain wax 88 after first paragraph Fischer-Tropsch synthetic wax 13 mixes and go out device as product.Second segment Fischer-Tropsch synthesis device top product 33 carries out gas-liquid separation at high pressure hot separator 114 after interchanger 113 and unstripped gas heat exchange, isolate high pressure hot separator liquid 37 and high pressure hot separator gas 34, high pressure hot separator gas 34 is again after interchanger 115 and unstripped gas heat exchange, fall within the range of 50 ℃ of left and right, carry out gas-liquid separation at cold high pressure separator 116, isolate cold high pressure separator liquid 36 and cold high pressure separator gas 10.The part of cold high pressure separator gas 10 is as tail gas 38 discharges, and quantity discharged is CO+H in tail gas ₂content determine, to guarantee CO+H in tail gas ₂content be not less than 40%, CO+H in tail gas ₂content higher than 50%, reduce quantity discharged; CO+H in tail gas ₂content lower than 40%, increase quantity discharged.Remaining most of cold high pressure separator gas 27 enters decarbonization system and (takes off CO ₂system) 109, gas is contacted with decarbonization solvent 5 at decarbonization system 109, the most of CO in gas ₂enter decarbonization solvent and form alkaline residue 50 discharge decarbonization systems 109, remove CO ₂after gas as circulation gas 35 with from the synthetic cold high pressure separator gas 4 of first paragraph Fischer-Tropsch, mix after enter recycle gas compressor 110 and boost, the mixed gas 40 after boosting returns to second segment Fischer-Tropsch synthesis device entrance after heat exchange.One, after the cold high pressure separator liquid 6 of two sections and 36 mixes, enter cold low separator 118 again with after thermal low-pressure separators gas 39 mixes, be separated into synthetic cold low separator product (the light ends oil) 58 of Fischer-Tropsch synthetic water 68, Fischer-Tropsch and the cold low separator gas 48 that contain oxygenatedchemicals and go out device; One, two sections high pressure hot separator liquid 37 and 11 enters thermal low-pressure separators 117 after mixing and is separated into thermal low-pressure separators liquid (heavy distillate) 78 and thermal low-pressure separators gas 39, heavy distillate 78 wherein goes out device as product, thermal low-pressure separators gas 39 (for example, cooling to 5～50 ℃) after cooling is mixed into cold low separator 118 with cold high pressure separator liquid 6,36 to be separated.

Fischer-Tropsch synthesis is strong exothermal reaction.For keeping Fischer-Tropsch synthesis device Jiang Taichuan district to operate under constant temperature, adopt, in the reactor slurry district, steam coils is set, make the hot water flowed through in slurries and steam coils carry out heat exchange, after the heat absorption of part hot water, the mode of equality of temperature vaporization is discharged reaction heat.The reaction heat of first paragraph Fischer-Tropsch synthesis device 102 is by shifting out in reactor with the rear mode of paying product water vapor 26 that produces of hot water exchange.After carrying out heat exchange from slurries in the hot water 23 of steam pockets 101 and first paragraph Fischer-Tropsch synthesis device, steam and the hot water mixture of the vaporization of forming section hot water equality of temperature return to steam pockets 101, water vapor 26 wherein discharges after by steam pockets 101 pressure-controlling, and the liquid level of steam pockets is maintained by supplementing hot water 21.Similarly, the reaction heat of second segment Fischer-Tropsch synthesis device 112 is by shifting out in reactor with the rear mode that produces by-product water vapor 25 of hot water exchange.After carrying out heat exchange from slurries in the hot water 24 of steam pockets 111 and second segment Fischer-Tropsch synthesis device, steam and the hot water mixture of the vaporization of forming section hot water equality of temperature return to steam pockets 111, water vapor 25 wherein discharges after by steam pockets 111 pressure-controlling, and the liquid level of steam pockets is maintained by supplementing hot water 22.Two required supplementary hot water 20 of steam pockets provide by device is outer, and the water vapour given off through pressure-controlling gathers becomes the by-product of device water vapor 28 discharge Fischer-Tropsch synthesizers, or as the thermal source utilization.

It will be appreciated by those skilled in the art that the first paragraph Fischer-Tropsch synthesis device 102 shown in Fig. 1 can be one, a plurality of (more than 2) that also can be in parallel, for example 2,3,4; Equally, second segment Fischer-Tropsch synthesis device 112 can be one, a plurality of (more than 2) that also can be in parallel, for example 2,3,4.

Method of the present invention overcomes take the facility investment existed when synthetic gas is produced liquid product as raw material by conventional Fischer-Tropsch synthesis method and the shortcoming that process cost is high, space-time yield is low, the CO utilization ratio is low, integrated technique simultaneously, simplify technical process, and be suitable for large-scale industrial production.

Experimental section

I. the effective gas dividing potential drop test of entrance

The contriver utilizes stirring tank slurry reactor device and Fe-series catalyst to divide the Fischer-Tropsch synthesis performance of depressing to test to the effective gas of different reactor entrance, the results are shown in Table 1.

The effective gas dividing potential drop of table 1 different reactor entrance test-results

The condition numbering	Condition 1	Condition 2
			Processing condition:
Virgin gas gas agent ratio, Nml/g/h	8400	7140
			Virgin gas H ₂/ CO ratio, v/v	1.7	1.7
Virgin gas a nitrogen content, mol%	8	8
			The circulation of tail gas ratio, v/v	2.33	2.75
The reactor inlet empty tower gas velocity, cm/s	Benchmark	Benchmark
			Temperature of reaction, ℃	Benchmark	Benchmark
Reaction pressure, MPa	Benchmark	Benchmark
			Test-results:
The CO total conversion rate, %	75	81
			CO ₂Selectivity, mol%	13.3	14.7
CH ₄Selectivity, mol%	3.6	4.4
			The CO per pass conversion, %	30	32
C ₅ ⁺Space-time yield, g/g-cat/h	1.0	0.9
			A nitrogen content in circulation gas, mol%	18	21

As seen from the data in Table 1, maintaining under identical reactor inlet empty tower gas velocity, temperature of reaction and reaction pressure, when the agent of fresh synthesis gas gas drops to the 7140Nml/g-cat./h of condition 2 than the 8400Nml/g-cat./h from condition 1, although the CO total conversion rate can be improved, but because the effective gas of reactor inlet divides drops, space-time yield descends, and the device oil offtake reduces.Test-results shows, under identical empty tower gas velocity, the effective gas dividing potential drop that improves as far as possible reactor inlet is conducive to improve the oil-producing capacity of device.

II. different in moisture is depressed the speed of reaction test

By feed gas conditions, be CO ₂mole fraction 0.3, CO mole fraction 0.2, H ₂mole fraction 0.4, reaction total pressure P=2MPa is tested, and obtains Fischer-Tropsch synthesis speed data that different in moisture depresses in Table 2:

Table 2 different in moisture is depressed the Fischer-Tropsch synthesis speed ratio

From table 2 test-results, although to the susceptibility difference of water partial pressure, lowering water-content in feeding gas, different catalyzer all can increase substantially Fischer-Tropsch synthesis speed.If the water-content in feeding gas is removed to 90% from 0.05%, to 0.005% (50ppm) (volume ratio), Fischer-Tropsch synthesis speed can improve 11%～93%, and visual effects is very obvious.

Embodiment

Embodiment 1

The present embodiment adopts the technical process shown in Fig. 1, after fresh feed gas is gasification, through the H purified and water-gas shift obtains ₂with the volume ratio of CO be 1.54 synthetic gas, wherein H ₂content is that 60.7%, CO content is 39.3% (volume ratio).

One, two section of the present embodiment all adopts Fe-series catalyst, and catalyzer is the SFT418-7 that the exploitation of Beijing research institute of China Shenhua Coal to Liquid and Chemical Co., Ltd., Zhejiang Twrd New Material Co., Ltd. produce.Before carrying out Fischer-Tropsch synthesis, catalyzer reduces processing in reactor.

Under Fischer-Tropsch synthesis processing condition listed at table 3, carry out.

Comparative example 1 (multiple process)

For usefulness of the present invention is described better, select the two cover separate unit reactor Fischer-Tropsch synthesizer multiple processes that current heavy industrialization is implemented to compare.Processing condition during multiple process are in Table 3 last row.

The processing condition of table 3 embodiment 1 and comparative example 1 Fischer-Tropsch synthesis

* annotate: 1) in comparative example 1, two reactor process conditions are identical;

2) the gas agent is than the ratio that is feed gas volumetric flow rate and catalyst in reactor quality in the unit time.

The concrete data of the actual effect of technique of the present invention are in Table 4.

Table 4 experimental result

In embodiment 1, when the first paragraph Fischer-Tropsch is synthetic, fresh raw material of synthetic gas once passes through, and the CO transformation efficiency is 54.6%.After the first paragraph Fischer-Tropsch synthesis, contraction of gas, for meeting second segment Fischer-Tropsch synthesis device entrance empty tower gas velocity, need to supplement the synthetic circulation gas of second segment Fischer-Tropsch, and recycle ratio is 0.76v/v.The synthetic CO per pass conversion of second segment Fischer-Tropsch is 61.8%, and total conversion rate reaches 81.4%.One, two sections integrated rear total reaction results are: the CO total conversion rate reaches 91.7%, CO ₂selectivity (accounting for the CO mole ratio of conversion) is 25.3%, CH ₄selectivity (accounting for the mole ratio of total generation hydrocarbon) is 6.7%, and the hydrocarbon space-time yield reaches 0.735g/g-cat./h.

Under the conditions such as identical catalyzer and reactor inlet empty tower gas velocity, temperature of reaction and reaction pressure, during multiple process, the integrated result of two cover separate unit reactor assemblies is: the CO per pass conversion is 59.7%, and total conversion rate is only 83.6%, CO ₂selectivity (accounting for the CO mole ratio of conversion) is 23.5%, CH ₄selectivity (accounting for the mole ratio of total generation hydrocarbon) is 6.6%, and the hydrocarbon space-time yield is 0.705g/g-cat./h.During this comparative example, the recycle ratio of every reactor is 1.0v/v, need two recycle gas compressors, and the recycle gas total amount has reached the fresh synthesis gas amount.Usually, in order to improve the CO utilization ratio, the CO total conversion rate need to be brought up to operation more than 90%, now need to reduce the fresh synthesis gas amount, more than improving recycle ratio to 1.5.

From the embodiment result, technique of the present invention is compared with existing common process, in identical fresh synthesis gas amount of finish situation, and CO ₂and CH ₄selectivity is suitable; The CO total conversion rate is high 8 percentage points; Device is produced hydrocarbon products output (space-time yield) and is relatively improved 4%; Reduce by a recycle gas compressor; The circulating flow rate needed descends 58%, but gas circulation compression system process cost decrease.

Embodiment 2

The present embodiment adopts the technical process shown in Fig. 1, after fresh feed gas is gasification, through the H purified and water-gas shift obtains ₂with the volume ratio of the CO synthetic gas that is 1.8.

One, two section of the present embodiment all adopts Fe-series catalyst, and catalyzer is identical with embodiment 1.Processing condition are listed in table 5.

Embodiment 3

The present embodiment adopts the technical process shown in Fig. 1, the H of fresh feed gas for being obtained by Sweet natural gas ₂with the volume ratio of the CO synthetic gas that is 2.

One, two section of the present embodiment all adopts cobalt series catalyst, catalyzer consist of 15Co: 5Zr: 100Al ₂o ₃.The preparation method, for pouring the zirconium nitrate aqueous solution into according to first wetting method in 500 ℃ of baked aluminum oxide in advance in air, then uses rotary drum dehydration by evaporation, drying, according to first humidity method, adds Co (NO again ₃) ₂6H ₂the O aqueous solution, again flood the aqueous solution of Jing Ti/Bao Pian COBALT NITRATE CRYSTALS/FLAKES after drying, as above be total to three times repeatedly, until in catalyst precursors, cobalt contents meets the requirements, add a certain amount of binding agent, through extrusion, pelletizing, drying, roasting, obtain qualified cobalt series catalyst after reduction is processed.Processing condition are listed in table 5.

Table 5 embodiment 2 and 3 processing condition

Table 6 embodiment 2 and 3 experimental result

Common process will reach the CO total conversion rate identical with the present invention, needs to reduce the fresh synthesis gas amount of finish, increases recycle ratio.Device capbility further descends, and recycle gas compression energy consumption further increases.

Above embodiment be take paste state bed reactor present invention is described as example, and those skilled in the art understand, above-mentioned technique and system also are applicable to fixed bed, fixed fluidized bed, fluidized-bed after suitable adjustment.

Certainly, the present invention also can have other embodiments, the foregoing is only the preferred embodiment of the present invention, not is used for limiting protection scope of the present invention; Without departing from the spirit of the invention, those of ordinary skills are every makes various corresponding variations and modification according to content of the present invention, all belongs to the protection domain of claim of the present invention.

Claims

1. a two stage Fischer-Tropsch synthesis method comprises the following steps:

A) first paragraph Fischer-Tropsch synthesis

Make to contain CO and H ₂unstripped gas enter first paragraph Fischer-Tropsch synthesis device (102), carry out Fischer-Tropsch synthesis under the effect of catalyzer, obtain first paragraph Fischer-Tropsch synthesis product;

B) separation of first paragraph Fischer-Tropsch synthesis product

Described first paragraph Fischer-Tropsch synthesis product is separated, water is separated with unconverted tail gas, obtained the unconverted tail gas (4) of hydrocarbon product, first paragraph Fischer-Tropsch synthesis;

C) second segment Fischer-Tropsch synthesis

By step b) in the described unconverted tail gas (4) that obtains enter second segment Fischer-Tropsch synthesis device (112), carry out Fischer-Tropsch synthesis under the effect of catalyzer, obtain second segment Fischer-Tropsch synthesis product;

D) separation of second segment Fischer-Tropsch synthesis product

Described second segment Fischer-Tropsch synthesis product is separated, water is separated with unconverted tail gas, obtained the unconverted tail gas of hydrocarbon product, second segment Fischer-Tropsch synthesis

(10), the part of the unconverted tail gas of described second segment Fischer-Tropsch synthesis (27) is returned to described second segment Fischer-Tropsch synthesis device (112) circulating reaction;

Wherein, the unconverted tail gas (4) of described first paragraph Fischer-Tropsch synthesis does not return to described first paragraph Fischer-Tropsch synthesis device (102) circulating reaction, step a) in, fresh synthesis gas as described unstripped gas one way by described first paragraph Fischer-Tropsch synthesis device;

Wherein, step b) with steps d) in the described top product (2 that comprises Fischer-Tropsch synthesis that separates; 33) oil-water-gas separates; Described b) oil-water of the top product of first paragraph Fischer-Tropsch synthesis (2)-gas separates and described d) oil-water of the top product (33) of second segment Fischer-Tropsch synthesis-gas separates and comprises the following steps:

At first, adopt high pressure hot separator (104; 114) carry out flash separation, obtain high pressure hot separator liquid (11; 37), high pressure hot separator gas (3; 34);

Then, by described high pressure hot separator gas (3; 34) adopt cold high pressure separator (106; 116) carry out flash separation, obtain two-phase: the blended liquid phase product (6 that cold high pressure separator liquid is light ends oil and water; 36), cold high pressure separator gas is unconverted tail gas (4; 10);

Wherein, control the middle CO transformation efficiency of described first paragraph Fischer-Tropsch synthesis device (102) at 30%-70%.

2. two stage Fischer-Tropsch synthesis method according to claim 1 wherein, further comprises:

E) by the described high pressure hot separator liquid (11 of described first paragraph, second segment Fischer-Tropsch synthesis; 37) pass into thermal low-pressure separators (117), flash separation obtains the heavy ends oil production as thermal low-pressure separators liquid (78) and thermal low-pressure separators gas (39); And

F) alternatively, by the described cold high pressure separator liquid (6 of described first paragraph, second segment Fischer-Tropsch synthesis; 36) and optional described thermal low-pressure separators gas (39) pass into cold low separator (118), flash separation obtains cold low separator gas (48), light ends oil production (58), water (68).

3. two stage Fischer-Tropsch synthesis method according to claim 1, wherein,

Described high pressure hot separator (104; 114) operation under 120～220 ℃;

Described cold high pressure separator (106; 116) operation under 5～60 ℃.

4. two stage Fischer-Tropsch synthesis method according to claim 1, wherein,

Described high pressure hot separator (104; 114) operation under 140～180 ℃;

Described cold high pressure separator (106; 116) operation under 10～50 ℃.

5. two stage Fischer-Tropsch synthesis method according to claim 2, wherein,

Described thermal low-pressure separators (117) moves under 60～200 ℃;

Described cold low separator (118) is 5～60 ℃ of operations.

6. two stage Fischer-Tropsch synthesis method according to claim 2, wherein,

Described thermal low-pressure separators (117) is 70～180 ℃ of operations;

Described cold low separator (118) moves under 20～50 ℃.

7. two stage Fischer-Tropsch synthesis method according to claim 6, wherein,

Described thermal low-pressure separators (117) moves under 80～160 ℃.

8. two stage Fischer-Tropsch synthesis method according to claim 6, wherein,

Described thermal low-pressure separators (117) moves under 90～140 ℃.

9. according to the described two stage Fischer-Tropsch synthesis method of claim 1 to 8 any one, wherein, control the middle CO transformation efficiency of described first paragraph Fischer-Tropsch synthesis device (102) 40%～65%.

10. according to the described two stage Fischer-Tropsch synthesis method of claim 1 to 8 any one, wherein, control the middle CO transformation efficiency of described first paragraph Fischer-Tropsch synthesis device (102) 50%～60%.

11. according to the described two stage Fischer-Tropsch synthesis method of claim 1 to 8 any one, wherein,

Step a) described in first paragraph Fischer-Tropsch synthesis and/or step c) described in the second segment Fischer-Tropsch synthesis under following reaction conditions, carry out:

Temperature of reaction is 200～320 ℃;

Reaction pressure is 15～50bar;

Reactor inlet gas empty tower gas velocity is 10～40cm/s;

The reactor inlet volumetric flow of gas is 2000～50000Nml/g-cat./h with the ratio of catalyst quality.

12. according to the described two stage Fischer-Tropsch synthesis method of claim 1 to 8 any one, wherein,

Temperature of reaction is 235～275 ℃;

Reaction pressure is 20～40bar;

Reactor inlet gas empty tower gas velocity is 15～35cm/s;

The reactor inlet volumetric flow of gas is 5000～30000Nml/g-cat./h with the ratio of catalyst quality.

13. according to the described two stage Fischer-Tropsch synthesis method of claim 1 to 8 any one, wherein,

Temperature of reaction is 245～265 ℃;

Reaction pressure is 25～35bar;

Reactor inlet gas empty tower gas velocity is 15～25cm/s;

The reactor inlet volumetric flow of gas is 8000～20000Nml/g-cat./h with the ratio of catalyst quality.

14., according to the described two stage Fischer-Tropsch synthesis method of claim 1 to 8 any one, wherein, described first paragraph Fischer-Tropsch synthesis device (102) and described second segment Fischer-Tropsch synthesis device (112) are one or a plurality of paste state bed reactors in parallel.

15. two stage Fischer-Tropsch synthesis method according to claim 14, wherein, the number of described first paragraph Fischer-Tropsch synthesis device (102) equals or more than the number of described second segment Fischer-Tropsch synthesis device (112).

16. two stage Fischer-Tropsch synthesis method according to claim 14, wherein, described first paragraph Fischer-Tropsch synthesis device (102) is a paste state bed reactor or a plurality of paste state bed reactors in parallel, and described second segment Fischer-Tropsch synthesis device (112) is a paste state bed reactor.

17. according to the described two stage Fischer-Tropsch synthesis method of claim 1 to 8 any one, wherein, CO and H in described unstripped gas ₂volume ratio be 0.67～2.2.

18. according to the described two stage Fischer-Tropsch synthesis method of claim 1 to 8 any one, wherein, CO and H in described unstripped gas ₂volume ratio be 0.8～2.

19. according to the described two stage Fischer-Tropsch synthesis method of claim 1 to 8 any one, wherein, CO and H in described unstripped gas ₂volume ratio be 1～2.

20. according to the described two stage Fischer-Tropsch synthesis method of claim 1 to 8 any one, wherein, CO and H in described unstripped gas ₂volume ratio be 1.4～2.

21. according to the described two stage Fischer-Tropsch synthesis method of claim 1 to 8 any one, wherein, step a) and c) in the catalyzer that uses be Fe-series catalyst or cobalt series catalyst.

22. two stage Fischer-Tropsch synthesis method according to claim 21, wherein, when adopting Fe-series catalyst, the H of described unstripped gas ₂with the volume ratio of CO be 1.4～1.8.

23. two stage Fischer-Tropsch synthesis method according to claim 21, wherein, when adopting Fe-series catalyst, the H of described unstripped gas ₂with the volume ratio of CO be 1.4～1.7.

24. two stage Fischer-Tropsch synthesis method according to claim 21, wherein, when adopting Fe-series catalyst, the H of described unstripped gas ₂with the volume ratio of CO be 1.5～1.7.

25. two stage Fischer-Tropsch synthesis method according to claim 21, wherein, when adopting Fe-series catalyst, the H of described unstripped gas ₂with the volume ratio of CO be 1.5～1.6.

26. two stage Fischer-Tropsch synthesis method according to claim 21, wherein, when adopting cobalt series catalyst, the H of described unstripped gas ₂with the volume ratio of CO be 1.8～2.2.

27. two stage Fischer-Tropsch synthesis method according to claim 21, wherein, when adopting cobalt series catalyst, the H of described unstripped gas ₂with the volume ratio of CO be 1.9～2.1.

28. two stage Fischer-Tropsch synthesis method according to claim 21, wherein, when adopting cobalt series catalyst, the H of described unstripped gas ₂with the volume ratio of CO be 1.95～2.05.

29. according to the described two stage Fischer-Tropsch synthesis method of claim 1 to 8 any one, wherein, the unconverted tail gas of described second segment Fischer-Tropsch synthesis mixes with the unconverted tail gas of whole described first paragraph Fischer-Tropsch synthesis, then enters described second segment Fischer-Tropsch synthesis device (112).

30. two stage Fischer-Tropsch synthesis method according to claim 29, wherein, the unconverted tail gas of described second segment Fischer-Tropsch synthesis is 0.5～5 with the unconverted tail gas mixed volume ratio of described first paragraph Fischer-Tropsch synthesis.

31. two stage Fischer-Tropsch synthesis method according to claim 29, wherein, the unconverted tail gas of described second segment Fischer-Tropsch synthesis is 1～3 with the unconverted tail gas mixed volume ratio of described first paragraph Fischer-Tropsch synthesis.

32. two stage Fischer-Tropsch synthesis method according to claim 29, wherein, the unconverted tail gas of described second segment Fischer-Tropsch synthesis is 1.5～2.5 with the unconverted tail gas mixed volume ratio of described first paragraph Fischer-Tropsch synthesis.

33. two stage Fischer-Tropsch synthesis method according to claim 29, wherein, before mixing, remove the CO in the unconverted tail gas of described second segment Fischer-Tropsch synthesis ₂.

34. two stage Fischer-Tropsch synthesis method according to claim 29, wherein, remove CO ₂adopt hot salt of wormwood to take off CO ₂method or WATER-WASHING METHOD are carried out.

35. according to the described two stage Fischer-Tropsch synthesis method of claim 1 to 8 any one, wherein, step a) described in unstripped gas for through purifying and the synthetic gas of water-gas shift.

36., according to the described two stage Fischer-Tropsch synthesis method of claim 1 to 8 any one, wherein, enter the described unconverted tail gas water-content of described second segment Fischer-Tropsch synthesis device (112) by volume lower than 0.05%.

37., according to the described two stage Fischer-Tropsch synthesis method of claim 1 to 8 any one, wherein, enter the described unconverted tail gas water-content of described second segment Fischer-Tropsch synthesis device (112) by volume lower than 0.01%.

38., according to the described two stage Fischer-Tropsch synthesis method of claim 1 to 8 any one, wherein, enter the described unconverted tail gas water-content of described second segment Fischer-Tropsch synthesis device (112) by volume lower than 0.005%.

39., according to the described two stage Fischer-Tropsch synthesis method of claim 1 to 8 any one, wherein, enter the described unconverted tail gas water-content of described second segment Fischer-Tropsch synthesis device (112) by volume lower than 0.0001%.

40. the two stage Fischer-Tropsch synthesis system comprises:

A) first paragraph Fischer-Tropsch synthesis device (102), wherein accommodate fischer-tropsch synthetic catalyst, and described first paragraph Fischer-Tropsch synthesis device (102) at least has:

The first paragraph reactor inlet, be positioned at the bottom of described first paragraph Fischer-Tropsch synthesis device (102);

The first paragraph reactor head exports, and is positioned at the top of described first paragraph Fischer-Tropsch synthesis device (102);

First paragraph Fischer-Tropsch synthetic wax or slurries export, and are positioned at the Jiang Taichuan district of described first paragraph Fischer-Tropsch synthesis device (102);

B) first paragraph separation system, separated for the top product (2) to from described first paragraph reactor head outlet, and water is separated with unconverted tail gas, obtains the unconverted tail gas of hydrocarbon product, first paragraph Fischer-Tropsch synthesis; Described first paragraph separation system has:

First paragraph separation system entrance, be connected with described first paragraph reactor head outlet;

A plurality of first paragraph separation system outlet comprise:

The outlet of first paragraph hydrocarbon product, and

Tail gas outlet that first paragraph is unconverted;

C) second segment Fischer-Tropsch synthesis device (112), wherein accommodate fischer-tropsch synthetic catalyst, and described second segment Fischer-Tropsch synthesis device (112) at least has:

The second segment reactor inlet, be positioned at the bottom of described second segment Fischer-Tropsch synthesis device (112), and be connected with the unconverted tail gas outlet of described first paragraph;

The second segment reactor head exports, and is positioned at the top of described second segment Fischer-Tropsch synthesis device (112);

Second segment Fischer-Tropsch synthetic wax or slurries export, and are positioned at the Jiang Taichuan district of described second segment Fischer-Tropsch synthesis device (102);

D) second segment separation system, for the top product (33) to from described second segment reactor head outlet, separated, water is separated with unconverted tail gas, obtain the unconverted tail gas of hydrocarbon product, second segment Fischer-Tropsch synthesis, described second segment separation system has:

Second segment separation system entrance, be connected with described second segment reactor head outlet;

A plurality of second segment separation system outlet comprise:

The outlet of second segment hydrocarbon product, and

Tail gas outlet that second segment is unconverted;

Wherein, described first paragraph is unconverted, and the tail gas outlet does not connect described first paragraph reactor inlet, makes fresh synthesis gas pass through described first paragraph Fischer-Tropsch synthesis device as the unstripped gas one way.

Wherein, described B) first paragraph separation system and described D) the second segment separation system comprises oil-water-air separation.

Wherein, described B) first paragraph separation system and described D) oil-water-gas separating system of second segment separation system comprises:

High pressure hot separator (104; 114), have:

The high pressure hot separator entrance, with described first paragraph separation system entrance or

Described second segment separation system entrance is connected,

The high pressure hot separator liquid exit, and

The high pressure hot separator pneumatic outlet;

Cold high pressure separator (106; 116), have:

The cold high pressure separator entrance, be connected with described high pressure hot separator pneumatic outlet,

The cold high pressure separator liquid exit, and

The cold high pressure separator pneumatic outlet.

41., according to the described two stage Fischer-Tropsch synthesis system of claim 40, further comprise:

Thermal low-pressure separators (117) has:

The thermal low-pressure separators entrance, be connected with the described high pressure hot separator liquid exit of described first paragraph separation system and/or described second segment separation system,

The thermal low-pressure separators pneumatic outlet,

The thermal low-pressure separators liquid exit;

Alternatively, cold low separator (118) has:

The cold low separator inlet, be connected with described thermal low-pressure separators liquid exit and/or described cold high pressure separator liquid exit,

The outlet of cold low separator gas,

The light ends oil export,

The outlet of Fischer-Tropsch synthetic water.

42., according to the described two stage Fischer-Tropsch synthesis system of claim 40 or 41, further comprise de-CO ₂system (109), described de-CO ₂system (109) has:

De-CO ₂colvent inlet,

De-CO ₂solvent outlet,

De-CO ₂the system gas entrance, be connected with described cold high pressure separator pneumatic outlet,

De-CO ₂the system gas outlet, be connected with described second segment reactor inlet.

43., according to the described two stage Fischer-Tropsch synthesis system of claim 40 or 41, wherein, described first paragraph Fischer-Tropsch synthesis device (102) and described second segment Fischer-Tropsch synthesis device (112) are one or a plurality of paste state bed reactors in parallel.

44., according to the described two stage Fischer-Tropsch synthesis system of claim 43, wherein, the number of described first paragraph Fischer-Tropsch synthesis device (102) is more than or equal to the number of described second segment Fischer-Tropsch synthesis device (112).

45. according to the described two stage Fischer-Tropsch synthesis system of claim 43, wherein, described first paragraph Fischer-Tropsch synthesis device (102) is one or a plurality of paste state bed reactors in parallel, and described second segment Fischer-Tropsch synthesis device (112) is a paste state bed reactor.

46., according to the described two stage Fischer-Tropsch synthesis system of claim 40 or 41, further comprise:

Wax filter, be arranged on inside or the outside of described first paragraph Fischer-Tropsch synthesis device (102) and described second segment Fischer-Tropsch synthesis device (112).