Microwave plasma alcoholysis product separation and purification system and method

Abstract

The invention belongs to the technical field of energy environmental protection, and discloses a microwave plasma alcoholysis product separation and purification system and method. The system comprises a water washing tower, a gas-liquid separation tank, a first compressor, a first cooler, a pretreatment unit, a first membrane separator, a second membrane separator, a second compressor, a second cooler and an adsorption tower. The method comprises the following steps: firstly, removing residual alcohol substances in alcoholysis products through a water washing process; purifying and recovering hydrogen in the alcoholysis product through a two-stage membrane separation process; and finally, impurities in the hydrogen are removed through an adsorption process, high-purity hydrogen is produced, and the hydrogen not only can reach the hydrogenation process standard of an oil refinery, but also can reach the fuel cell standard. The method is high in hydrogen recovery rate and has remarkable economic, environmental and social benefits.

Description

Technical Field

[0001] The invention belongs to the technical field of energy and environmental protection, and relates to a system and method for separating and purifying microwave plasma alcoholysis products. Background Art

[0002] Microwave plasma alcoholysis hydrogen production is an emerging and inexpensive hydrogen production technology. In the process of hydrogen production, a large amount of carbon monoxide, carbon dioxide, methane, ethane and other gases will be produced as by-products, as well as unreacted alcohol substances, resulting in insufficient hydrogen purity, which cannot meet the standards of refinery hydrogenation process and fuel cells, and the alcoholysis products need to be separated and purified. At present, there is no separation and purification technology for microwave plasma alcoholysis products, so it is necessary to develop a new separation and purification technology to meet the needs of separation and purification of microwave plasma alcoholysis products. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a system and method for separating and purifying a microwave plasma alcoholysis product.

[0004] The technical solution of the present invention:

[0005] A method for separating and purifying a microwave plasma alcoholysis product comprises the following steps:

[0006] Step 1: alcoholysis product S-1 enters from the lower side of water scrubber 1, and water S-2 enters from the upper side of water scrubber 1, and the two are in countercurrent contact, and the alcohol substances in alcoholysis product S-1 are absorbed and removed by water; alcohol-containing water S-4 is obtained at the bottom of water scrubber 1 and removed outside the boundary; dealcoholization raw gas S-3 obtained at the top of water scrubber 1 enters gas-liquid separation tank 2, and the liquid entrained in dealcoholization raw gas S-3 is removed by gas-liquid separation; liquid S-6 is obtained at the bottom of gas-liquid separation tank 2 and returned to water scrubber 1; gas S-5 coming out of the top of gas-liquid separation tank 2 is compressed by the first compressor 3, cooled by the first cooler 4, and pretreated by the pretreatment unit 5 in turn to obtain purified raw gas S-9;

[0007] Step 2: The purified raw gas S-9 enters the first membrane separator 6, hydrogen is enriched on the permeate side of the first membrane separator 6 to obtain the first permeate gas S-11, and the first permeate gas S-10 depleted in hydrogen is obtained on the retentate side of the first membrane separator 6; the first permeate gas S-10 enters the second membrane separator 7, hydrogen is enriched on the permeate side of the second membrane separator 7 to obtain the second permeate gas S-13; the second permeate gas S-13 returns to the gas-liquid separation tank 2, and the second permeate gas S-12 depleted in hydrogen is obtained on the retentate side of the second membrane separator 7, and is removed out of the boundary;

[0008] Step 3: The first permeate gas S-11 is compressed by the second compressor 8 and cooled by the second cooler 9, and enters the adsorption tower 10. Under the action of the adsorbent, impurities in the first permeate gas S-11 are removed to obtain high-purity hydrogen S-16, which is removed as a product outside the boundary area; the bottom analysis gas S-17 of the adsorption tower 10 returns to the gas-liquid separator 2.

[0009] Further, in step 1, the pretreatment unit 5 is a liquid separator, a heat exchanger, a precision filter and a demister.

[0010] Further, in step 2, the low-pressure side outlet of the first membrane separator 6 and the second membrane separator 7 is the permeate side, and the high-pressure side outlet is the retentate side, and the membrane material used is a central control fiber membrane, a flat membrane or a spiral membrane.

[0011] Furthermore, in step 3, more than two decarbonization towers 10 are provided, and a pressure reduction regeneration method is adopted, and an adsorbent is filled inside, and the adsorbent is one or a mixture of two or more of alumina, activated carbon, silica gel, and molecular sieve.

[0012] Furthermore, the central control fiber membrane, flat membrane, spiral membrane are organic membranes, inorganic membranes, composite membranes or mixed matrix membranes.

[0013] Furthermore, the composition of the microwave plasma alcoholysis product is that the volume fraction of carbon monoxide component is 10-30%, the volume fraction of hydrogen component is 32-70%, and the volume fraction of carbon dioxide, methanol, ethanol, methane, ethane, ethylene and acetylene components are all less than 10%.

[0014] A microwave plasma alcoholysis product separation and purification system, comprising a water washing tower 1, a gas-liquid separation tank 2, a first compressor 3, a first cooler 4, a pretreatment unit 5, a first membrane separator 6, a second membrane separator 7, a second compressor 8, a second cooler 9 and an adsorption tower 10;

[0015] The alcoholysis product S-1 is introduced into the lower inlet of the water washing tower 1, and the water S-2 and liquid S-6 are introduced into the upper inlet of the tower; the top and bottom outlets of the water washing tower 1 are respectively connected to the inlet of the gas-liquid separation tank 2 and the interface outside the boundary of the alcohol-containing water S-4; the top outlet of the gas-liquid separation tank 2 is connected to the inlet of the first compressor 3; the outlet of the first compressor 3 is connected to the inlet of the first cooler 4; the outlet of the first cooler 4 is connected to the inlet of the pretreatment unit 5; the outlet of the pretreatment unit 5 is connected to the inlet of the first membrane separation 6; the retentate of the first membrane separator 6 The side outlet end is connected to the inlet end of the second membrane separator 7; the permeate side outlet end of the second membrane separator 7 is connected to the upper side inlet end of the gas-liquid separation tank 2; the retentate side outlet end of the second membrane separator 7 is connected to the interface end outside the fuel gas S-12 boundary area; the permeate side outlet end of the first membrane separator 6 is connected to the inlet end of the second compressor 8; the outlet end of the second compressor 8 is connected to the inlet end of the second cooler 9; the outlet end of the second cooler 9 is connected to the inlet end of the adsorption tower 10; the outlet end of the adsorption tower 10 is respectively connected to the inlet end of the gas-liquid separator tank 2 and the interface end outside the hydrogen S-16 boundary area.

[0016] Beneficial effects of the invention: The invention provides a microwave plasma alcoholysis product separation and purification system and method, which first removes the alcohol substances remaining in the alcoholysis product through a water washing process; then purifies and recovers the hydrogen in the alcoholysis product through a two-stage membrane separation process; finally, removes impurities in the hydrogen through an adsorption process to produce high-purity hydrogen, which can meet the hydrogenation process standards of oil refineries and the standards of fuel cells. The method has a high hydrogen recovery rate and has significant economic, environmental and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A flow chart of a system and method for separating and purifying a microwave plasma alcoholysis product proposed by the present invention;

[0018] In the figure: 1, water washing tower; 2, gas-liquid separation tank; 3, first compressor; 4, first cooler; 5, pretreatment unit; 6, first membrane separator; 7, second membrane separator; 8, second compressor; 9, second cooler; 10, adsorption tower; S-1, alcoholysis product; S-2, water; S-3, dealcoholization raw gas; S-4, alcohol-containing water; S-5, dealcoholization dehydration raw gas; S-6, liquid; S-7, high-pressure dealcoholization dehydration raw gas; S-8, high-pressure normal temperature dealcoholization dehydration raw gas; S-9, purified raw gas; S-10, first retentate gas; S-11, first permeate gas; S-12, second retentate gas; S-13, second permeate gas; S-14, high-pressure crude hydrogen; S-15, high-pressure normal temperature crude hydrogen; S-16, hydrogen; S-17, analytical gas. DETAILED DESCRIPTION

[0019] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and technical solutions.

[0020] Example

[0021] like Figure 1 shown.

[0022] This embodiment discloses a microwave plasma alcoholysis product separation and purification system and method, which is used for microwave plasma alcoholysis product separation and purification. The alcoholysis product composition in this embodiment is a carbon monoxide component with a volume fraction of 26.25%, a hydrogen component with a volume fraction of 58.56%, a carbon dioxide component with a volume fraction of 0.2%, a C1 component (including methanol and methane) with a volume fraction of 4.24%, a C2 component (including ethane, ethylene, and acetylene) with a volume fraction of 10.45%, an oxygen component with a volume fraction of 0.06%, a nitrogen component with a volume fraction of 0.24%, and an alcoholysis product flow rate of 3Nm 3 / h. By adopting the technical solution of the present invention, hydrogen with a concentration of more than 99.97 mol% of the fuel cell standard can be produced, and the hydrogen recovery rate is 92.27%.

[0023] In this embodiment, the microwave plasma alcoholysis product separation and purification method is:

[0024] Step 1: The alcoholysis product S-1 enters the water washing tower 1 from the bottom of the tower, and the water S-2 enters the water washing tower 1 from the top of the tower. The two are in countercurrent contact, and the alcohol substances in the alcoholysis product are absorbed and removed by water. The alcohol-containing water S-4 is obtained at the bottom of the tower outside the boundary area, and the dealcoholization raw gas S-3 is obtained at the top of the tower. It enters the gas-liquid separation tank 2 for gas-liquid separation, and the liquid entrained in the raw gas is removed. The liquid S-6 is obtained at the bottom of the tank and returned to the water washing tower 1. The gas coming out of the top of the tank is compressed by the first compressor 3, cooled by the first cooler 4, and pretreated by the pretreatment unit 5 to obtain the purified raw gas S-9.

[0025] Step 2: The purified raw gas S-9 enters the first membrane separator 6, and hydrogen is preferentially permeated over carbon monoxide, alkanes and other gases. Hydrogen is enriched on the permeate side of the first membrane separator 6 to obtain the first permeate gas S-11, and the purity of hydrogen is greatly improved. The first permeate gas S-10 depleted in hydrogen is obtained on the permeate side of the first membrane separator 6. The first permeate gas S-10 enters the second membrane separator 7, and hydrogen is enriched on the permeate side of the second membrane separator 7 to obtain the second permeate gas S-11. The hydrogen is recovered, and the second permeate gas S-13 is returned to the gas-liquid separation tank 2. The second permeate gas S-12 depleted in hydrogen is obtained on the permeate side of the second membrane separator 7 and is removed outside the boundary.

[0026] Step 3: The first permeate gas S-11 is compressed by the second compressor 8, cooled by the second cooler 9, and enters the adsorption tower 10. Under the action of the adsorbent, impurities in the first permeate gas are removed to obtain high-purity hydrogen S-16, which is removed from the boundary area as a product, and the analyzed gas S-17 returns to the gas-liquid separator 2.

[0027] In this embodiment, the microwave plasma alcoholysis product separation and purification system includes a water washing tower 1, a gas-liquid separation tank 2, a first compressor 3, a first cooler 4, a pretreatment unit 5, a first membrane separator 6, a second membrane separator 7, a second compressor 8, a second cooler 9 and an adsorption tower 10;

[0028] The alcoholysis product S-1 is introduced into the lower inlet end of the water scrubber 1, and the water S-2 and liquid S-6 are introduced into the upper inlet end; the two outlet ends of the water scrubber 1 are respectively connected to the inlet end of the gas-liquid separation tank 2 and the interface end outside the boundary area of ​​the alcohol-containing water S-4; the outlet end of the gas-liquid separation tank 2 is respectively connected to the upper inlet end of the water scrubber 1 and the inlet end of the first compressor 3; the outlet end of the first compressor 3 is connected to the inlet end of the first cooler 4; the outlet end of the first cooler 4 is connected to the inlet end of the pretreatment unit 5; the outlet end of the pretreatment unit 5 is connected to the inlet end of the first membrane separation 6; the first membrane separation The outlet end of the retentate side of the device 6 is connected to the inlet end of the second membrane separator 7; the outlet end of the permeate side of the second membrane separator 7 is connected to the inlet end of the gas-liquid separation tank 2; the outlet end of the retentate side of the second membrane separator 7 is connected to the interface end outside the fuel gas S-12 boundary area; the outlet end of the permeate side of the first membrane separator 6 is connected to the inlet end of the second compressor 8; the outlet end of the second compressor 8 is connected to the inlet end of the second cooler 9; the outlet end of the second cooler 9 is connected to the inlet end of the adsorption tower 10; the outlet end of the adsorption tower 10 is respectively connected to the inlet end of the gas-liquid separator tank 2 and the interface end outside the hydrogen S-16 boundary area.

[0029] The water washing tower 1 has a diameter of 0.2m, a height of 0.7m, an operating temperature of 35°C, and an operating pressure of 50kPaG.

[0030] The gas-liquid separation tank 2 is vertical, with a diameter of 0.2m and a volume of 0.02m 3 .

[0031] The first compressor 3 is a reciprocating compressor with a power of 0.8 kW; the second compressor 8 is a reciprocating compressor with a power of 0.3 kW.

[0032] The heat exchange area of ​​the first cooler 4 is 0.1m 2 ; The heat exchange area of ​​the second cooler 9 is 0.1m 2 .

[0033] The first membrane separator 6 uses a medium fiber membrane with a membrane area of ​​0.9m 2 The membrane inlet pressure is 2.25MPaG, and the permeate side pressure is 0.2MPaG; the second membrane separator 7 uses a medium fiber membrane with a membrane area of ​​0.4m 2 , the membrane inlet pressure is 2.18MPaG and the permeate side pressure is 0.2MPaG.

[0034] The adsorption tower 10 is filled with active adsorbent, silica gel adsorbent and molecular sieve adsorbent. Three towers are set up, one for operation, one for regeneration and one for standby. The adsorption pressure is 2.6 MPaG and the desorption pressure is 70 kPaG.

[0035] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for separating and purifying a microwave plasma alcoholysis product, characterized in that: The following steps are involved: Step 1: The alcoholysis product (S-1) enters from the lower side of the water scrubber (1), and water (S-2) enters from the upper side of the water scrubber (1). The two are in countercurrent contact, and the alcohol substances in the alcoholysis product (S-1) are absorbed and removed by water. The operating temperature of the water scrubber is 5 to 75°C, and the operating pressure is normal pressure to 2MPaG; the alcohol-containing water (S-4) is obtained at the bottom of the water scrubber (1) and removed to the outside; the dealcoholization raw gas (S-3) obtained at the top of the water scrubber (1) enters the gas-liquid separation tank (2) and is separated by gas-liquid separation tank (2). The liquid entrained in the dealcoholization raw gas (S-3) is separated and removed; the liquid (S-6) is obtained at the bottom of the gas-liquid separation tank (2) and returned to the water scrubber (1); the gas (S-5) coming out of the top of the gas-liquid separation tank (2) is compressed by the first compressor (3), cooled by the first cooler (4), and pretreated by the pretreatment unit (5) to obtain the purified raw gas (S-9), the outlet pressure of the first compressor (3) is 0.6-10 MPaG, and the outlet temperature of the process gas side of the first cooler (4) is 10-50°C; Step 2: The purified raw gas (S-9) enters the first membrane separator (6), hydrogen is enriched on the permeate side of the first membrane separator (6) to obtain the first permeate gas (S-11), and the first permeate gas (S-10) depleted in hydrogen is obtained on the permeate side of the first membrane separator (6); the first permeate gas (S-10) enters the second membrane separator (7), hydrogen is enriched on the permeate side of the second membrane separator (7) to obtain the second permeate gas (S-13); the second permeate gas (S-13) returns to the gas-liquid separation tank (2), and the second permeate gas (S-12) depleted in hydrogen is obtained on the permeate side of the second membrane separator (7), and is removed out of the boundary; Step 3: The first permeate gas (S-11) is compressed by the second compressor (8) and cooled by the second cooler (9) and enters the adsorption tower (10). Under the action of the adsorbent, impurities in the first permeate gas (S-11) are removed to obtain high-purity hydrogen (S-16), which is removed as a product outside the boundary area; the decomposed gas (S-17) of the adsorption tower (10) returns to the gas-liquid separator (2), the outlet pressure of the second compressor (8) is 0.6-10MPaG, and the process gas side outlet of the second cooler (9) is 10-50°C.

2. The method for separating and purifying the microwave plasma alcoholysis product according to claim 1, characterized in that: In step 1, the pretreatment unit (5) is a liquid separator, a heat exchanger, a precision filter and a demister, and the outlet temperature of the process gas side of the heat exchanger is 60 to 90°C.

3. The method for separating and purifying the microwave plasma alcoholysis product according to claim 1, characterized in that: In step 2, the low-pressure side outlet of the first membrane separator (6) and the second membrane separator (7) is the permeate side, and the pressures are 5kPaG~5MPaG and normal pressure~2MPaG respectively, and the high-pressure side outlet is the retentate side. The membrane material used is a central control fiber membrane, a flat membrane or a spiral membrane.

4. The method for separating and purifying the microwave plasma alcoholysis product according to claim 1, characterized in that: In step 3, more than two decarbonization towers (10) are provided, and a pressure reduction regeneration method is adopted, and an adsorbent is filled inside. The adsorbent is one or a mixture of two or more of alumina, activated carbon, silica gel, and molecular sieve.

5. The method for separating and purifying the microwave plasma alcoholysis product according to claim 3, characterized in that: The central control fiber membrane, flat membrane, and spiral membrane are organic membranes, inorganic membranes, composite membranes, or mixed matrix membranes.

6. The method for separating and purifying the microwave plasma alcoholysis product according to claims 1-5, characterized in that: The composition of the microwave plasma alcoholysis product is that the volume fraction of carbon monoxide component is 10-30%, the volume fraction of hydrogen component is 32-70%, and the volume fraction of carbon dioxide, methanol, ethanol, methane, ethane, ethylene and acetylene components are all less than 10%.

7. A microwave plasma alcoholysis product separation and purification system, based on the microwave plasma alcoholysis product separation and purification method according to any one of claims 1 to 5, characterized in that: The system comprises a water washing tower (1), a gas-liquid separation tank (2), a first compressor (3), a first cooler (4), a pretreatment unit (5), a first membrane separator (6), a second membrane separator (7), a second compressor (8), a second cooler (9) and an adsorption tower (10); The alcoholysis product (S-1) is introduced into the lower inlet of the water washing tower (1), and water (S-2) and liquid (S-6) are introduced into the upper inlet of the water washing tower (1); the top and bottom outlets of the water washing tower (1) are respectively connected to the inlet of the gas-liquid separation tank (2) and the interface outside the boundary of the alcohol-containing water (S-4); the top outlet of the gas-liquid separation tank (2) is connected to the inlet of the first compressor (3); the outlet of the first compressor (3) is connected to the inlet of the first cooler (4); the outlet of the first cooler (4) is connected to the inlet of the pretreatment unit (5); the outlet of the pretreatment unit (5) is connected to the inlet of the first membrane separation (6); the first membrane separator (6) The outlet end of the retentate side is connected to the inlet end of the second membrane separator (7); the outlet end of the permeate side of the second membrane separator (7) is connected to the inlet end of the upper side of the gas-liquid separation tank (2); the outlet end of the retentate side of the second membrane separator (7) is connected to the interface end outside the fuel gas (S-12) boundary area; the outlet end of the permeate side of the first membrane separator (6) is connected to the inlet end of the second compressor (8); the outlet end of the second compressor (8) is connected to the inlet end of the second cooler (9); the outlet end of the second cooler (9) is connected to the inlet end of the adsorption tower (10); the outlet end of the adsorption tower (10) is respectively connected to the inlet end of the gas-liquid separation tank (2) and the interface end outside the hydrogen (S-16) boundary area.

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