阅读说明：本技术 一种膜分离和变压吸附耦合调节合成气氢碳比同时副产氢气的系统 (System for regulating hydrogen-carbon ratio of synthesis gas and simultaneously producing hydrogen by coupling membrane separation and pressure swing adsorption ) 是由 何绍辉 徐徜徉 杨文皓 于 2021-10-09 设计创作，主要内容包括：本发明公开了一种膜分离和变压吸附耦合调节合成气氢碳比同时副产氢气的系统,原料气首先进入膜分离器,在分离膜两侧压差的推动下得到渗透气和非渗透气,渗透气经过变压吸附提纯高浓度产品氢气和一氧化碳浓度较高的解析气,解析气经压缩机增压后与膜分离非渗透气混合成氢碳比达到要求的合成气。通过调节膜分离的操作压力或膜分离面积调整进入变压吸附的渗透气量,从而调节变压吸附的生产氢气量,来调节合成气的氢碳比。本发明充分利用了膜分离和变压吸附两种气体分离方法的各自优点,整套系统能耗低、无外排废气产生,同时达到调节合成气氢碳比和副产高浓度氢气的目的。(The invention discloses a system for regulating the hydrogen-carbon ratio of synthesis gas and coproducing hydrogen by coupling membrane separation and pressure swing adsorption. The permeation gas amount entering the pressure swing adsorption is adjusted by adjusting the operating pressure of the membrane separation or the membrane separation area, so that the hydrogen production amount of the pressure swing adsorption is adjusted, and the hydrogen-carbon ratio of the synthesis gas is adjusted. The invention fully utilizes the respective advantages of the membrane separation method and the pressure swing adsorption method, the whole system has low energy consumption and no outward exhaust gas, and simultaneously achieves the purposes of regulating the hydrogen-carbon ratio of the synthesis gas and producing the byproduct high-concentration hydrogen.)

1. The system for regulating the hydrogen-carbon ratio of synthesis gas and simultaneously producing hydrogen by-product through coupling of membrane separation and pressure swing adsorption is characterized in that a feed gas (11) enters a membrane separator (1), a permeation gas (13) of the membrane separator (1) enters a pressure swing adsorption device (2), a desorption gas (14) of the pressure swing adsorption device (2) is mixed with a non-permeation gas (12) of the membrane separator (1) according to a target hydrogen-carbon ratio after being pressurized by a compressor (3) to obtain a synthesis gas (16), and the other end of the pressure swing adsorption device (2) outputs hydrogen (15) which is secondarily purified through membrane separation and pressure swing adsorption.

2. The system for regulating the hydrogen-carbon ratio of synthesis gas and simultaneously producing hydrogen by-product through coupling of membrane separation and pressure swing adsorption according to claim 1, wherein the desorbed gas (14) of the pressure swing adsorption device (2) is pressurized by a compressor (3), then is cooled by a water cooler (4) and then is mixed with the non-permeate gas (12).

3. The system for regulating the hydrogen-carbon ratio of the synthesis gas and simultaneously producing the hydrogen as a byproduct by coupling membrane separation and pressure swing adsorption according to claim 1, wherein the feed gas (11) is pretreated before the membrane separator (1) to ensure that the gas entering the membrane does not contain liquid and solid impurities and does not contain alkaline substances such as ammonia, and then the feed gas is heated to be far away from the saturated dew point.

4. The system for regulating the hydrogen-carbon ratio of the synthesis gas and simultaneously producing the hydrogen as a byproduct by coupling membrane separation and pressure swing adsorption according to claim 1, wherein the hydrogen-carbon ratio of the synthesis gas is regulated by regulating the operating pressure of the membrane separator (1) or the area of the separation membrane or regulating the operating pressure and the membrane area of the membrane separation at the same time.

Technical Field

The invention relates to the field of gas separation of coal chemical industry and petrochemical industry, in particular to a system for regulating the hydrogen-carbon ratio of synthesis gas and simultaneously producing hydrogen as a byproduct by using a membrane separation and pressure swing adsorption coupling process.

Background

The production of different chemical products from synthesis gas requires that the synthesis gas has different hydrogen-carbon ratios, for example; the hydrogen-carbon ratio required by Fischer-Tropsch synthesis is 3-3.6; the hydrogen-carbon ratio required for synthesizing the methanol is 2.05-2.25; the hydrogen-carbon ratio of the production of dipropylheptanol (2 PH) is required to be maintained at 1.02 as much as possible; the oxo reaction requires a hydrogen-carbon ratio of about 1 and the synthesis ammonia requires a hydrogen-nitrogen ratio of 3, so that the adjustment of the synthesis gas is an essential adjustment means for the production.

With the technological progress, the modernized coal or natural gas prepared synthesis gas generally has higher gas making pressure which can reach the fixed bed pressurized coal gasification pressure of 2.4MPa and the fluidized bed coal gasification pressure of 3.0-6.5MPa, so that the crude synthesis gas has higher pressure, and the gas is conveniently separated by adopting a membrane separation method.

The hydrogen-carbon ratio of the crude synthesis gas can be adjusted in the preorder production section by means of gas making, secondary conversion, fresh hydrogen supplement, carbon supplement and the like, but the crude synthesis gas is limited by production conditions, is complex to operate and cannot meet the requirements of subsequent production.

The conversion rate of the synthesis reaction in the large-scale coal chemical industry is not high, the synthesis reaction is generally a cyclic hydrogenation process, hydrogen has recovery value as an excessive reactant, and meanwhile, hydrogen is widely popularized and used in the current state as a novel clean energy source, and the synthesis gas byproduct, namely high-concentration hydrogen, has wide application prospect.

In addition to cryogenic separation, the membrane separation and pressure swing adsorption involved in the present invention are the main gas separation technologies and have wide applications in the gas recovery field of coal chemical industry and petrochemical industry, for example: recovering hydrogen in purge gas of methanol synthesis and ammonia synthesis, and purifying reformed hydrogen by pressure swing adsorption; recovering hydrogen from hydrogen-containing exhaust gas in hydrocracking or hydrofining production, and preparing hydrogen from methanol cracking gas by pressure swing adsorption.

There are also reports and patent applications for adjusting the hydrogen-carbon ratio of synthesis gas by using membrane separation or pressure swing adsorption technology alone, such as using a new type of gas with the patent publication number of CN201065400Y to co-produce methanol, namely using a membrane separation device to recover hydrogen in methanol purge gas and return the hydrogen to synthesis reaction to increase the hydrogen-carbon ratio of synthesis gas. The invention patent of publication No. CN111232923A is a method for regulating hydrogen-carbon ratio of natural gas direct cracking circulation reaction gas by pressure swing adsorption. Application publication No. CN108384572A is a method for adjusting the hydrogen-carbon ratio of Fischer-Tropsch synthesis and co-producing hydrogen by pressure swing adsorption technology.

The method is limited by the characteristics of pressure swing adsorption and membrane separation technology, the single technology for adjusting the hydrogen-carbon ratio of the synthesis gas and producing high-concentration hydrogen cannot be widely applied in practice, the membrane separation technology is feasible for adjusting the hydrogen-carbon ratio of the synthesis gas, but the technology can only obtain the hydrogen with the purity of less than 99 percent generally, and meanwhile, the pressure of the permeation gas needs to be reduced greatly, and the energy consumption is high; the advantage of membrane separation is that the non-permeate gas is not depressurized.

The pressure swing adsorption technology is widely applied in the field of preparing high-concentration hydrogen, but the pressure of the desorption gas as the synthesis gas is generally close to the normal pressure after the pressure swing adsorption, and the energy consumption of pressurization is high, so the pressure swing adsorption technology cannot be widely applied in the field of synthesis gas regulation. Generally, the synthetic gas amount of a large-scale coal chemical device is larger, the load of pressure swing adsorption and analysis is increased, and the investment is greatly increased.

Disclosure of Invention

In order to solve the problems described in the background art and overcome the technical defects of regulating the hydrogen-carbon ratio of the synthesis gas and producing hydrogen by-product by a single technology, the invention provides a system for regulating the hydrogen-carbon ratio of the synthesis gas and producing hydrogen by-product by a membrane separation and pressure swing adsorption coupling process.

The invention is realized by the following steps:

the crude synthesis raw material gas (11) with higher pressure and higher hydrogen-carbon ratio firstly enters a membrane separator (1) to obtain permeate gas with reduced pressure and non-permeate gas with reduced pipeline resistance under the pushing of the pressure difference at two sides of a separation membrane; the concentration of the hydrogen of the permeation gas obtained by membrane separation is about 80% -98%, the pressure of the permeation gas obtained by membrane separation can ensure that the permeation gas enters the requirement of pressure swing adsorption for purifying the hydrogen, and the pressure of the non-permeation gas is not reduced;

the permeation gas (13) of the membrane separator (1) enters a pressure swing adsorption device (2), the gas (14) decomposed by the pressure swing adsorption device (2) and the non-permeation gas (12) of the membrane separator (1) are mixed according to a target hydrogen-carbon ratio to obtain synthesis gas (16), the gas (14) with high carbon monoxide concentration has less amount of analysis gas but low pressure, and can be separated from the membrane to obtain the non-permeation gas (12) as the synthesis gas after being pressurized by a compressor (3), components in the low-pressure gas (such as carbon monoxide, carbon dioxide and the like) are main raw materials of the synthesis gas, if the gas is discharged outside, material loss can be caused, and the synthesis gas (16) with a certain hydrogen-carbon ratio, which is obtained after being mixed with the non-permeation gas of the membrane separator, can be reused.

The other end of the pressure swing adsorption device (2) outputs hydrogen (15) which is secondarily purified through membrane separation and pressure swing adsorption, and product hydrogen with the concentration of 99.0% -99.99% can be obtained.

Furthermore, the gas (14) which is desorbed from the pressure swing adsorption device (2) is pressurized by the compressor (3), then is cooled by the water cooler (4), and then is mixed with the non-permeable gas (12).

Furthermore, the raw gas (11) is pretreated before the membrane separator (1) to ensure that the membrane gas does not contain liquid and solid impurities and does not contain alkaline substances such as ammonia, and then the raw gas is heated to make the raw gas far away from the saturated dew point.

Furthermore, the purpose of adjusting the hydrogen-carbon ratio of the synthesis gas is achieved by adjusting the operating pressure of the membrane separator (1) or the using area of the separation membrane or adjusting the operating pressure and the membrane area of the membrane separation at the same time.

Compared with the prior art, the invention has the beneficial effects that:

the non-hydrogen impurities of the membrane separation permeation gas entering the pressure swing adsorption are greatly reduced, the using amount of an adsorbent of the pressure swing adsorption is greatly reduced, and the scale, investment and operating cost of the pressure swing adsorption device are far less than the method for adjusting the hydrogen-carbon ratio of the synthesis gas by using the pressure swing adsorption device alone.

The permeation gas amount entering the pressure swing adsorption is adjusted by adjusting the operating pressure of the membrane separation or the membrane separation area, so that the hydrogen yield of the pressure swing adsorption is adjusted, and the hydrogen-carbon ratio of the synthesis gas is finally adjusted. The pressure drop of the non-permeable gas of the membrane separation is little, and the use pressure of the synthesis gas is ensured.

The analysis gas amount after pressure swing adsorption is less, the power consumption of the compressor is reduced, and the operation cost is reduced.

The invention fully utilizes the respective advantages of the membrane separation method and the pressure swing adsorption method, the whole system has low energy consumption and no outward exhaust gas, and simultaneously achieves the purposes of regulating the hydrogen-carbon ratio of the synthesis gas and producing the byproduct high-concentration hydrogen.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a block diagram of a system.

FIG. 2 is a schematic of a separate pressure swing adsorption process flow.

In the figure: 1. a membrane separator; 2. a pressure swing adsorption device; 3. a compressor; 4. a water cooler; 11. raw material gas; 12. a non-permeate gas; 13. permeating gas; 14. and (5) gas is resolved.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings of the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

As shown in fig. 1, a crude synthesis raw material gas 11 with higher pressure and higher hydrogen-carbon ratio firstly enters a membrane separator 1, and a permeate gas with reduced pressure and a non-permeate gas with reduced pipeline resistance are obtained under the pushing of the pressure difference at two sides of a separation membrane; the concentration of the hydrogen of the permeation gas obtained by membrane separation is about 80% -98%, the pressure of the permeation gas obtained by membrane separation can ensure that the permeation gas enters the requirement of pressure swing adsorption for purifying the hydrogen, and the pressure of the non-permeation gas is not reduced;

the permeate gas 13 of the membrane separator 1 enters the pressure swing adsorption device 2, the gas 14 decomposed by the pressure swing adsorption device 2 is mixed with the non-permeate gas 12 of the membrane separator 1 according to a target hydrogen-carbon ratio to obtain a synthesis gas 16, the gas 14 decomposed by carbon monoxide with higher concentration has less gas amount, but the pressure is very low, the gas can be pressurized by the compressor 3 to be taken as the synthesis gas together with the membrane-separated non-permeate gas 12, components in the low-pressure gas are main raw materials of the synthesis gas, such as carbon monoxide, carbon dioxide and the like, if the gas is discharged outside, the material loss can be caused, and the synthesis gas 16 with a certain hydrogen-carbon ratio, which is obtained after being mixed with the non-permeate gas of the membrane separator, can be reused.

The other end of the pressure swing adsorption device 2 outputs hydrogen 15 which is secondarily purified through membrane separation and pressure swing adsorption, and product hydrogen with the concentration of 99.0% -99.99% can be obtained.

The pressure swing adsorption device 2 is characterized in that the gas 14 to be analyzed is pressurized by the compressor 3, then is cooled by the water cooler 4, and then is mixed with the non-permeable gas 12.

The feed gas 11 is pretreated before the membrane separator 1 to ensure that the membrane gas does not contain liquid and solid impurities and does not contain alkaline substances such as ammonia, and then the feed gas is heated to keep the feed gas away from a saturated dew point.

The purpose of adjusting the hydrogen-carbon ratio of the synthesis gas is achieved by adjusting the operating pressure of the membrane separator 1 or the using area of the separation membrane or adjusting the operating pressure and the membrane area of the membrane separation at the same time.

Example 1:

the conditions of crude raw material gas are as follows:

gas separation requirements:

product gas 1: the flow rate of the externally-sold hydrogen is about 6350Nm³H, purity H2 is more than 99.9%, and pressure is more than or equal to 2.4 MPaG.

And (3) product gas 2: the gases other than hydrogen are mixed into a "carbonylation synthesis gas" which is used as a feed to a downstream carbonylation unit. The "carbonylated syngas" is required to have a H2 to CO ratio of about 1:1 (molar ratio). The pressure is more than or equal to 2.3 MPaG.

The hydrogen concentration of the feed gas is 67 percent (mol, the same below), the pressure is 5.2MPa and is far higher than the pressure of two streams of product gases, the membrane separation and pressure swing adsorption coupling technology is very suitable for meeting the production requirement, the single membrane separation technology can not produce 99.9 percent of hydrogen products, and the comparison scheme of the single pressure swing adsorption technology is shown in a comparison example 2.

The raw material gas firstly enters a membrane separator, the non-permeable gas only has pipeline resistance reduction of about 0.1-0.2MPa, and the flow rate of the non-permeable gas is 10177.3Nm³And h, the hydrogen-carbon ratio in the composition is 1.0371, the pressure is regulated to 2.3MPa through a pressure reducing valve, and the carbonyl synthesis gas is used as the main part of the carbonyl synthesis gas and is mixed with the subsequent pressure swing adsorption analysis gas.

The pressure of the permeating gas for membrane separation is set to be 2.4MPa and equal to the required pressure of the product hydrogen, and the flow rate of the permeating gas is 8317.04Nm³And h, the hydrogen concentration is 86.257%, and the permeation gas enters a pressure swing adsorption device to produce product gas with the hydrogen output outside, wherein the hydrogen output outside is 6462.83Nm3/h, the concentration is 99.9% and the pressure is 2.4 MPa. The pressure of the pressure swing adsorption desorption gas is 0.1MPa, the hydrogen-carbon ratio is 0.792, and the pressure is increased to 2.3MPa by a compressor, and the raw gas is mixed with non-permeation gas to form the oxo-synthesis raw material gas with the hydrogen-carbon ratio of 0.9942.

The material balance table is as follows:

the main energy consumption of the system is about 263Kw, and the system investment is divided into three parts, namely membrane separation investment, pressure swing adsorption investment and compressor investment.

Comparative example 2

One technical option is to use pressure swing adsorption technology alone to produce hydrogen and oxo gas to meet the gas separation requirements of example 1, and the schematic flow diagram is shown in figure 2 as a separate pressure swing adsorption process flow diagram.

The comparison example is that one part of raw material gas directly enters a pressure swing adsorption device to produce the product hydrogen with the same specification, and the pressure swing adsorption and desorption gas is compressed and then mixed with the other part of raw material gas to form the synthesis gas with qualified hydrogen-carbon ratio.

The mass balance for comparative example 2 is as follows:

the investment of comparative example 2 was a pressure swing adsorption investment, a compressor investment, respectively. However, the investment cost of example 2 is higher than that of example 1 due to the influence of factors such as the scale of the plant, the adsorbent filling amount, the compressor air intake amount, and the like. The running cost can be only about 789Kw, which is far higher than 263Kw of the example 1.

The capital and operating costs for example 1 and comparative example 2 are compared in the following table:

it can be seen that the investment and operating costs of example 1 using the present invention are lower than those of comparative example 2.

Comparative example 3

A certain energy chemical company adopts a membrane separation technology, synthesis gas with a hydrogen-carbon ratio of 1.3-1.5 is adjusted into synthesis gas with a hydrogen-carbon ratio of 1.0-1.02, the synthesis gas is used for producing dipropylheptanol (2 PH), and the synthesis gas yield is 25000Nm³Per, and discharge 4465-8833 Nm³The hydrogen with the concentration of 90% and the pressure of 2.0MPa is used for other purposes, and the hydrogen does not produce high-concentration hydrogen products.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.