System and method for efficiently separating carbon monoxide, carbon dioxide and hydrogen sulfide

Abstract

The invention discloses a system and a method for efficiently separating carbon monoxide, carbon dioxide and hydrogen sulfide. The system comprises an absorption tower I, a heat exchanger I, a gas-liquid separator I, a solution filtering device, a heat exchanger II, a heat exchanger III, a solution desalting device, a barren liquor pump, a solution pump, a semi-barren liquor pump, a normal solution stripping tower, a reboiler, a heat exchanger IV, a gas-liquid separator II, an absorption tower II, a desulfurization tower, a rich liquor pump, a regeneration liquid pump, a regeneration tank, a sulfur foam tank and a sulfur foam pump. The method for efficiently separating the carbon monoxide, the carbon dioxide and the hydrogen sulfide, which is realized by the system, has the advantages of simple process flow, high separation efficiency, capability of selectively and respectively separating the carbon monoxide, the carbon dioxide and the hydrogen sulfide, and long-period operation stability.

Description

Technical Field

[0001] The present invention belongs to the field of gas separation, and is particularly suitable for the separation of gases containing carbon monoxide, carbon dioxide and hydrogen sulfide. Background Art

[0002] In the process of producing ethylene glycol from calcium carbide furnace gas, coke oven gas, and coal gasification synthesis gas, a shift process is often used to ensure that the hydrogen concentration in the raw material gas is greater than that of carbon monoxide. The shift process uses a sulfur-tolerant catalyst, and a certain amount of H2S is required to maintain the activity of the catalyst and prevent the reverse sulfidation of the catalyst. Therefore, in order to separate and purify carbon monoxide and hydrogen in the raw material gas and remove impurity gases such as carbon dioxide and hydrogen sulfide, a system and method for efficiently separating carbon monoxide, carbon dioxide and hydrogen sulfide are needed.

[0003] Patent CN110835556A introduces a wet desulfurization system and method for blast furnace gas. The specific device includes a hydrolysis reactor for hydrolyzing the gas and a solution absorption tank for absorbing sulfur-containing gases. The hydrolysis reactor is filled with a hydrolysis catalyst. An intake pipe is installed at the intake port of the hydrolysis reactor, and an outlet pipe is installed at the outlet port of the hydrolysis reactor. A first gas sampling port and a second gas sampling port are respectively opened on the intake pipe and the outlet pipe. The solution absorption tank is connected to the hydrolysis reactor through the outlet pipe. An exhaust pipe is installed at the outlet port of the solution absorption tank, and a third gas sampling port is opened on the exhaust pipe. The patent first performs a hydrolysis reaction using the hydrolysis reactor, and then uses the solution absorption tank to absorb sulfur-containing gases. Through the device and method provided by the above patent, hydrogen sulfide and carbon dioxide gases can be removed better, but there are problems of rapid decline in separation efficiency and incomplete separation during long-term operation, which have an adverse impact on the stable operation, energy conservation and consumption reduction, and safe and environmental protection operation of the overall ethylene glycol production device.

[0004] Therefore, in order to achieve the purpose of long-term operation of the production device, efficient separation of carbon monoxide, carbon dioxide and hydrogen sulfide, a new system and method for separating carbon monoxide, carbon dioxide and hydrogen sulfide gases are urgently needed. Summary of the Invention

[0005] In order to effectively solve the problems of rapid decline in separation efficiency and incomplete separation during long-term operation of the existing carbon monoxide, carbon dioxide and hydrogen sulfide separation devices, and ensure the long-term safe, environmental, efficient and energy-saving operation of the production device, the present invention provides a system and method for efficiently separating carbon monoxide, carbon dioxide and hydrogen sulfide. The system has the advantages of simple process flow, high separation efficiency, realizing selective separation of carbon monoxide, carbon dioxide and hydrogen sulfide respectively, and stable long-term operation.

[0006] The object of the present invention is achieved by the following technical solutions: The system for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide includes Absorption Tower I, Heat Exchanger I, Gas-Liquid Separator I, Solution Filtering Device, Heat Exchanger II, Heat Exchanger III, Solution Desalting Device, Lean Solution Pump, Solution Pump, Semi-Lean Solution Pump, Normal Desorption Stripping Tower, Reboiler, Heat Exchanger IV, Gas-Liquid Separator II, Absorption Tower II, Desulfurization Tower, Rich Solution Pump, Regenerated Solution Pump, Regeneration Tank, Sulfur Foam Tank, and Sulfur Foam Pump.

[0007] The top outlet of Absorption Tower I is connected to the inlet of Heat Exchanger I, the outlet of Heat Exchanger I is connected to the lower inlet of Gas-Liquid Separator I, and the upper outlet of Gas-Liquid Separator I is connected to a device outside the system; the lower outlet of Absorption Tower I is connected to the upper inlet of the Normal Desorption Stripping Tower, the top outlet of the Normal Desorption Stripping Tower is connected to the inlet of Heat Exchanger IV, the outlet of Heat Exchanger IV is connected to the lower inlet of Gas-Liquid Separator II, the upper outlet of Gas-Liquid Separator II is connected to the top inlet of Absorption Tower II, the middle outlet of Absorption Tower II is connected to the lower inlet of the Desulfurization Tower, and the upper outlet of the Desulfurization Tower is connected to a device outside the system; the lower outlet of Absorption Tower II is connected to the inlet of the Rich Solution Pump, the outlet of the Rich Solution Pump is connected to the upper inlet of the Regeneration Tank, the upper outlet of the Regeneration Tank is connected to the upper inlet of the Sulfur Foam Tank, the lower outlet of the Sulfur Foam Tank is connected to the inlet of the Sulfur Foam Pump, and the outlet of the Sulfur Foam Pump is connected to a device outside the system; the lower outlet of the Regeneration Tank is connected to the inlet of the Regenerated Solution Pump, and the outlet of the Regenerated Solution Pump is connected to the upper inlet of Absorption Tower II; the middle outlet of the Normal Desorption Stripping Tower is divided into two paths and is respectively connected to the inlet of the Semi-Lean Solution Pump and the inlet of the Solution Pump, and the outlet of the Semi-Lean Solution Pump is connected to the middle inlet of Absorption Tower I; the outlet of the Solution Pump is connected to the inlet of Heat Exchanger II, the outlet of Heat Exchanger II is connected to the middle inlet of the Normal Desorption Stripping Tower; the bottom outlet of the Normal Desorption Stripping Tower is connected to the inlet of Heat Exchanger II, the outlet of Heat Exchanger II is connected to the inlet of the Lean Solution Pump, the outlet of the Lean Solution Pump is connected to the inlet of Heat Exchanger III, and the outlet of Heat Exchanger III is connected to the upper inlet of Absorption Tower I.

[0008] For the system for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, a Solution Filtering Device is connected in parallel on the pipeline where the outlet of Heat Exchanger II is connected to the middle inlet of the Normal Desorption Stripping Tower to filter the solid impurities in Solution A.

[0009] For the system for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, the Solution Filtering Device includes a Mechanical Filter, an Activated Carbon Filter, and a Precision Filter connected in sequence. The filtration accuracy of the Mechanical Filter is 25 μm, and the filtration accuracy of the Precision Filter is 5 μm.

[0010] For the system for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, a Solution Desalting Device is connected in parallel on the pipeline where the outlet of Heat Exchanger II is connected to the inlet of the Lean Solution Pump to remove the heat-stable salts in Solution B.

[0011] The described system for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide, wherein the solution desalting device includes a bag filter and a resin tower connected in sequence, and the resin tower is filled with ion exchange resin.

[0012] The described system for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide, wherein the heat exchangers I, II, III, and IV are all shell-and-tube heat exchangers.

[0013] The described system for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide, wherein the absorption tower I, absorption tower II, and normal desorption stripping tower are all packed towers.

[0014] Using the described system for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide, the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide includes the following steps: (1) A mixed gas containing components such as carbon monoxide, carbon dioxide, and hydrogen sulfide enters the absorption tower I from the lower gas-phase inlet of the absorption tower I, and successively contacts the solution A entering the absorption tower I from the middle liquid-phase inlet of the absorption tower I and the solution B entering the absorption tower I from the upper liquid-phase inlet of the absorption tower I in a countercurrent manner. After the carbon dioxide and hydrogen sulfide in the mixed gas are absorbed by the solution A and B, a gas-liquid mixture is formed and enters the upper liquid-phase inlet of the normal desorption stripping tower; carbon monoxide flows out from the top gas-phase outlet of the absorption tower I, is cooled by the heat exchanger I, and then enters the gas-liquid separator I. After separating trace moisture in the gas-liquid separator I, it is sent to a device outside the system. (2) The gas-liquid mixture entering the normal desorption stripping tower from the upper liquid-phase inlet of the normal desorption stripping tower moves downward. The carbon dioxide and hydrogen sulfide in the gas-liquid mixture are desorbed. The carbon dioxide and hydrogen sulfide gases leave the normal desorption stripping tower from the top gas-phase outlet of the normal desorption stripping tower, are cooled by the heat exchanger IV, and then enter the gas-liquid separator II. After separating trace moisture in the gas-liquid separator II, they enter the absorption tower II from the top gas-phase inlet of the absorption tower II and contact the solution C entering from the upper liquid-phase inlet of the absorption tower II in the same direction. Most of the hydrogen sulfide in the mixed gas is absorbed by the solution C; carbon dioxide leaves the absorption tower II from the middle gas-phase outlet of the absorption tower II, and after removing trace hydrogen sulfide in the desulfurization tower, it is sent to a device outside the system. (3) The solution C that has absorbed hydrogen sulfide flows out from the bottom liquid-phase outlet of the absorption tower II, is sent to the regeneration tank by the rich liquid pump. Hydrogen sulfide reacts with the solution C, and hydrogen sulfide is oxidized to elemental sulfur. The sulfur foam containing elemental sulfur overflows from the upper part of the regeneration tank to the sulfur foam tank, and then is sent to a device outside the system by the sulfur foam pump; the solution C that has reacted with hydrogen sulfide reacts with the oxygen in the air entering from the upper gas-phase inlet of the regeneration tank to achieve the purpose of regenerating the solution C. The regenerated solution C is sent to the upper liquid-phase inlet of the absorption tower II by the regenerated liquid pump. (4) Solution A, from which most of the carbon dioxide and hydrogen sulfide have been resolved in the normal desorption stripper, flows out from the middle liquid phase outlet of the normal desorption stripper in two paths. One path is sent to the middle liquid phase inlet of Absorber I through the semi-lean liquid pump; the other path is sent to the inlet of Heat Exchanger II through the solution pump, and exchanges heat with Solution B, from which a small amount of carbon dioxide and hydrogen sulfide have been resolved, flowing out from the bottom liquid phase outlet of the normal desorption stripper, in Heat Exchanger II. After heat exchange, Solution A is divided into two paths. One path is directly sent to the middle liquid phase inlet of the normal desorption stripper, and the other path is sent to the middle liquid phase inlet of the normal desorption stripper after filtering the solid impurities in Solution A through the solution filtering device. (5) After heat exchange in Heat Exchanger II, Solution B is divided into two paths. One path is directly sent to the inlet of the lean liquid pump, and the other path is sent to the inlet of the lean liquid pump after removing the heat-stable salts in the solution through the solution desalting device; Solution B at the outlet of the lean liquid pump enters Absorber I from the upper liquid phase inlet of Absorber I after being cooled by Heat Exchanger III.

[0015] In the method for highly efficient separation of carbon monoxide, carbon dioxide and hydrogen sulfide as described above, Solution A is an MDEA solution containing 15 - 30 μL / L of carbon dioxide.

[0016] In the method for highly efficient separation of carbon monoxide, carbon dioxide and hydrogen sulfide as described above, Solution B is an MDEA solution containing 1 - 5 μL / L of carbon dioxide.

[0017] In the method for highly efficient separation of carbon monoxide, carbon dioxide and hydrogen sulfide as described above, Solution C is a complex iron solution.

[0018] In the method for highly efficient separation of carbon monoxide, carbon dioxide and hydrogen sulfide as described above, the liquid level of Absorber I is 1700 - 2700 mm; the pressure inside Absorber I is 1.0 - 2.0 MPa, and the pressure difference between the lower gas phase inlet and the upper gas phase outlet of Absorber I is 2 - 20 kPa; the temperature of the upper gas phase outlet of Absorber I is 30 - 80 °C.

[0019] In the method for highly efficient separation of carbon monoxide, carbon dioxide and hydrogen sulfide as described above, the temperature difference before and after Heat Exchanger I is 20 - 60 °C.

[0020] In the method for highly efficient separation of carbon monoxide, carbon dioxide and hydrogen sulfide as described above, the upper liquid level of the normal desorption stripper is 1800 - 2800 mm, and the lower liquid level is 2200 - 3500 mm; the pressure of the normal desorption stripper is 10 - 80 kPa, and the pressure difference between the upper and lower parts of the normal desorption stripper is 0.1 - 18 kPa; the temperature at the outlet of the reboiler is 100 - 120 °C; the temperature of the middle liquid phase outlet in the normal desorption stripper is 70 - 90 °C; the temperature of the bottom liquid phase outlet of the normal desorption stripper is 90 - 120 °C.

[0021] The method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, wherein the inlet pressure of the solution filtration device is 0.3 - 0.7 MPa.

[0022] The method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, wherein the liquid level of Absorption Tower II is 270 - 1300 mm; the pressure of Absorption Tower II is 8 - 40 kPa.

[0023] The method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, when the ion exchange resin in the resin tower of the solution desalting device reaches the working exchange capacity, it needs to be backwashed and regenerated with a sodium hydroxide solution with a mass fraction of 3% - 5%.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) By innovating the process flow and scientifically and reasonably setting the operating temperature and pressure, Absorption Tower I can efficiently absorb carbon dioxide and hydrogen sulfide gases, and Absorption Tower II can efficiently absorb hydrogen sulfide gas. Cooperating with the normal solution stripping tower operation, the beneficial effect of efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide is achieved. (2) The mixed gas is an acidic gas, which will corrode the packing in Absorption Tower I and the normal solution stripping tower. After the packing is corroded, the packing debris will be carried into the solution, resulting in an increase in the content of solid impurities in the MDEA solution and packing blockage. The present invention sets up a solution filtration device to perform three - stage filtration on the packing debris in the MDEA solution, realizing the efficient recycling of the MDEA solution, improving the economic efficiency of the system operation, and achieving the beneficial effect of long - term stable operation. (3) During normal production, in addition to absorbing carbon dioxide and hydrogen sulfide, the MDEA solution can also react with other acidic compounds existing in the system to form heat - stable salts. These heat - stable salts are not easily resolved under stripping conditions and will cause solution foaming, packing corrosion, and equipment corrosion, resulting in an increase in the consumption of the MDEA solution. Therefore, the present invention sets up a solution desalting device to remove the heat - stable salts in the MDEA solution, realizing the efficient recycling of the MDEA solution, improving the economic efficiency of the system operation, and achieving the beneficial effect of long - term stable operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation to the present invention.

[0026] Figure 1 It is the process flow chart of the present invention.

[0027] Figure 2 It is the flow chart of the solution desalting device of the present invention.

[0028] Figure 3 It is the flow chart of the solution filtration device of the present invention.

[0029] Figure 1 Among them, 1 is Absorption Tower I, 2 is Heat Exchanger I, 3 is Gas-Liquid Separator I, 4 is Solution Filtration Device, 5 is Heat Exchanger II, 6 is Heat Exchanger III, 7 is Solution Desalination Device, 8 is Lean Solution Pump, 9 is Solution Pump, 10 is Semi-Lean Solution Pump, 11 is Normal Desorption Stripping Tower, 12 is Reboiler, 13 is Heat Exchanger IV, 14 is Gas-Liquid Separator II, 15 is Absorption Tower II, 16 is Desulfurization Tower, 17 is Rich Solution Pump, 18 is Regenerated Liquid Pump, 19 is Regeneration Tank, 20 is Sulfur Foam Tank, 21 is Sulfur Foam Pump. Embodiment

[0030] Referring to the attached Figure 1 , the embodiment of the present invention provides a system and method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide. The system includes Absorption Tower I, Heat Exchanger I, Gas-Liquid Separator I, Solution Filtration Device, Heat Exchanger II, Heat Exchanger III, Solution Desalination Device, Lean Solution Pump, Solution Pump, Semi-Lean Solution Pump, Normal Desorption Stripping Tower, Reboiler, Heat Exchanger IV, Gas-Liquid Separator II, Absorption Tower II, Desulfurization Tower, Rich Solution Pump, Regenerated Liquid Pump, Regeneration Tank, Sulfur Foam Tank, Sulfur Foam Pump.

[0031] The top outlet of the Absorption Tower I is connected to the inlet of the Heat Exchanger I. The outlet of the Heat Exchanger I is connected to the lower inlet of the Gas-Liquid Separator I. The upper outlet of the Gas-Liquid Separator I is connected to a device outside the system. The lower outlet of the Absorption Tower I is connected to the upper inlet of the Normal Desorption Stripping Tower. The top outlet of the Normal Desorption Stripping Tower is connected to the inlet of the Heat Exchanger IV. The outlet of the Heat Exchanger IV is connected to the lower inlet of the Gas-Liquid Separator II. The upper outlet of the Gas-Liquid Separator II is connected to the top inlet of the Absorption Tower II. The middle outlet of the Absorption Tower II is connected to the lower inlet of the Desulfurization Tower. The upper outlet of the Desulfurization Tower is connected to a device outside the system. The lower outlet of the Absorption Tower II is connected to the inlet of the Rich Solution Pump. The outlet of the Rich Solution Pump is connected to the upper inlet of the Regeneration Tank. The upper outlet of the Regeneration Tank is connected to the upper inlet of the Sulfur Foam Tank. The lower outlet of the Sulfur Foam Tank is connected to the inlet of the Sulfur Foam Pump. The outlet of the Sulfur Foam Pump is connected to a device outside the system. The lower outlet of the Regeneration Tank is connected to the inlet of the Regenerated Liquid Pump. The outlet of the Regenerated Liquid Pump is connected to the upper inlet of the Absorption Tower II. The middle outlet of the Normal Desorption Stripping Tower is divided into two paths and is respectively connected to the inlet of the Semi-Lean Solution Pump and the inlet of the Solution Pump. The outlet of the Semi-Lean Solution Pump is connected to the middle inlet of the Absorption Tower I. The outlet of the Solution Pump is connected to the inlet of the Heat Exchanger II. The outlet of the Heat Exchanger II is connected to the middle inlet of the Normal Desorption Stripping Tower. The bottom outlet of the Normal Desorption Stripping Tower is connected to the inlet of the Heat Exchanger II. The outlet of the Heat Exchanger II is connected to the inlet of the Lean Solution Pump. The outlet of the Lean Solution Pump is connected to the inlet of the Heat Exchanger III. The outlet of the Heat Exchanger III is connected to the upper inlet of the Absorption Tower I.

[0032] Another embodiment is different in that, for the system for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, a solution filtration device is connected in parallel to the pipeline connecting the outlet of Heat Exchanger II to the middle inlet of the normal desorption stripper to filter the solid impurities in Solution A.

[0033] Another embodiment is different in that, for the system for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, the solution filtration device includes a mechanical filter, an activated carbon filter, and a precision filter connected in sequence. The filtration accuracy of the mechanical filter is 25 μm, and the filtration accuracy of the precision filter is 5 μm.

[0034] Another embodiment is different in that, for the system for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, a solution desalting device is connected in parallel to the pipeline connecting the outlet of Heat Exchanger II to the inlet of the lean liquid pump to remove the heat-stable salts in Solution B.

[0035] Another embodiment is different in that, for the system for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, the solution desalting device includes a bag filter and a resin tower connected in sequence. The resin tower is filled with ion exchange resin.

[0036] Another embodiment is different in that, for the system for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, Heat Exchanger I, Heat Exchanger II, Heat Exchanger III, and Heat Exchanger IV are all shell-and-tube heat exchangers.

[0037] Another embodiment is different in that, for the system for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, Absorption Tower I, Absorption Tower II, and the normal desorption stripper are all packed towers.

[0038] Using the system for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide includes the following steps: (1) A mixed gas containing components such as carbon monoxide, carbon dioxide, and hydrogen sulfide enters Absorption Tower I from the lower gas-phase inlet of Absorption Tower I, and successively contacts Solution A entering Absorption Tower I from the middle liquid-phase inlet of Absorption Tower I and Solution B entering Absorption Tower I from the upper liquid-phase inlet of Absorption Tower I in a countercurrent manner. After the carbon dioxide and hydrogen sulfide in the mixed gas are absorbed by Solution A and B, a gas-liquid mixture is formed and enters the upper liquid-phase inlet of the normal desorption stripper; carbon monoxide flows out from the top gas-phase outlet of Absorption Tower I, is cooled by Heat Exchanger I, and then enters Gas-Liquid Separator I. After separating trace amounts of moisture in Gas-Liquid Separator I, it is sent to a device outside the system; (2) The gas-liquid mixture entering the upper liquid phase inlet of the normal desorption stripper moves downward. Carbon dioxide and hydrogen sulfide in the gas-liquid mixture are desorbed. After the carbon dioxide and hydrogen sulfide gases leave the normal desorption stripper from the top gas phase outlet of the normal desorption stripper, they enter the gas-liquid separator II after being cooled by heat exchanger IV. After separating trace moisture in the gas-liquid separator II, they enter the absorption tower II from the top gas phase inlet of the absorption tower II, and come into countercurrent contact with solution C entering from the upper liquid phase inlet of the absorption tower II. Most of the hydrogen sulfide in the mixed gas is absorbed by solution C; carbon dioxide leaves the absorption tower II from the middle gas phase outlet of the absorption tower II, and after removing trace hydrogen sulfide through the desulfurization tower, it is sent to a device outside the system. (3) Solution C that has absorbed hydrogen sulfide flows out from the bottom liquid phase outlet of the absorption tower II, and is sent to the regeneration tank by the rich liquid pump. Hydrogen sulfide reacts with solution C, and hydrogen sulfide is oxidized to elemental sulfur. The sulfur foam containing elemental sulfur overflows from the upper part of the regeneration tank to the sulfur foam tank, and then is sent to a device outside the system by the sulfur foam pump; Solution C that has reacted with hydrogen sulfide reacts with the oxygen in the air entering from the upper gas phase inlet of the regeneration tank to achieve the purpose of regenerating solution C. The regenerated solution C is sent to the upper liquid phase inlet of the absorption tower II by the regenerated liquid pump. (4) Solution A in the normal desorption stripper from which most of the carbon dioxide and hydrogen sulfide have been desorbed flows out from the middle liquid phase outlet of the normal desorption stripper in two paths. One path is sent to the middle liquid phase inlet of the absorption tower I by the semi-lean liquid pump; the other path is sent to the inlet of heat exchanger II by the solution pump, and exchanges heat with solution B that has desorbed a small amount of carbon dioxide and hydrogen sulfide flowing out from the bottom liquid phase outlet of the normal desorption stripper in heat exchanger II; After heat exchange, solution A is divided into two paths. One path is directly sent to the middle liquid phase inlet of the normal desorption stripper, and the other path is sent to the middle liquid phase inlet of the normal desorption stripper after filtering the solid impurities in solution A through a solution filtering device. (5) After heat exchange in heat exchanger II, solution B is divided into two paths. One path is directly sent to the inlet of the lean liquid pump, and the other path is sent to the inlet of the lean liquid pump after removing the heat-stable salts in the solution through a solution desalting device; Solution B at the outlet of the lean liquid pump enters the absorption tower I from the upper liquid phase inlet of the absorption tower I after being cooled by heat exchanger III.

[0039] For the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, solution A is an MDEA solution containing 15 μL / L of carbon dioxide.

[0040] Another embodiment is different in that for the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, solution A is an MDEA solution containing 20 μL / L of carbon dioxide.

[0041] Another embodiment is different in that for the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, solution A is an MDEA solution containing 30 μL / L of carbon dioxide.

[0042] The method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, wherein solution B is an MDEA solution containing 1 μL / L of carbon dioxide.

[0043] Another embodiment is different in that, for the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, solution B is an MDEA solution containing 3 μL / L of carbon dioxide.

[0044] Another embodiment is different in that, for the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, solution B is an MDEA solution containing 5 μL / L of carbon dioxide.

[0045] For the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, solution C is a complex iron solution.

[0046] For the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, the liquid level of absorption tower I is 1700 mm; the pressure inside absorption tower I is 1.0 MPa, and the pressure difference between the lower gas phase inlet and the upper gas phase outlet at the bottom of absorption tower I is 2 kPa; the temperature of the upper gas phase outlet of absorption tower I is 30 °C.

[0047] Another embodiment is different in that, for the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, the liquid level of absorption tower I is 2200 mm; the pressure inside absorption tower I is 1.5 MPa, and the pressure difference between the lower gas phase inlet and the upper gas phase outlet at the bottom of absorption tower I is 10 kPa; the temperature of the upper gas phase outlet of absorption tower I is 50 °C.

[0048] Another embodiment is different in that, for the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, the liquid level of absorption tower I is 2700 mm; the pressure inside absorption tower I is 2.0 MPa, and the pressure difference between the lower gas phase inlet and the upper gas phase outlet at the bottom of absorption tower I is 20 kPa; the temperature of the upper gas phase outlet of absorption tower I is 80 °C.

[0049] For the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, the temperature difference before and after heat exchanger I is 20 °C.

[0050] Another embodiment is different in that, for the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, the temperature difference before and after heat exchanger I is 40 °C.

[0051] Another embodiment is different in that, for the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, the temperature difference before and after heat exchanger I is 60 °C.

[0052] The method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, wherein the liquid level at the upper part of the normal decomposition stripping column is 1800 mm, and the liquid level at the lower part is 2200 mm; the pressure at the upper part of the normal decomposition stripping column is 10 kPa, and the pressure at the lower part of the normal decomposition stripping column is 10.5 kPa; the outlet temperature of the reboiler is 100 °C; the liquid phase outlet temperature in the normal decomposition stripping column is 70 °C; the liquid phase outlet temperature at the bottom of the normal decomposition stripping column is 90 °C.

[0053] Another embodiment is different in that, for the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, the liquid level at the upper part of the normal decomposition stripping column is 2300 mm, and the liquid level at the lower part is 2800 mm; the pressure at the upper part of the normal decomposition stripping column is 40 kPa, and the pressure at the lower part of the normal decomposition stripping column is 50 kPa; the outlet temperature of the reboiler is 110 °C; the liquid phase outlet temperature in the normal decomposition stripping column is 80 °C; the liquid phase outlet temperature at the bottom of the normal decomposition stripping column is 105 °C.

[0054] Another embodiment is different in that, for the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, the liquid level at the upper part of the normal decomposition stripping column is 2800 mm, and the liquid level at the lower part is 3500 mm; the pressure at the upper part of the normal decomposition stripping column is 62 kPa, and the pressure difference at the lower part of the normal decomposition stripping column is 80 kPa; the outlet temperature of the reboiler is 120 °C; the liquid phase outlet temperature in the normal decomposition stripping column is 90 °C; the liquid phase outlet temperature at the bottom of the normal decomposition stripping column is 120 °C.

[0055] For the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, the inlet pressure of the solution filtration device is 0.3 - 0.7 MPa.

[0056] Another embodiment is different in that, for the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, the inlet pressure of the solution filtration device is 0.5 MPa.

[0057] Another embodiment is different in that, for the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, the inlet pressure of the solution filtration device is 0.7 MPa.

[0058] For the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, the liquid level of Absorption Tower II is 270 mm; the pressure of Absorption Tower II is 8 - 40 kPa.

[0059] Another embodiment is different in that, for the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, the liquid level of Absorption Tower II is 800 mm; the pressure of Absorption Tower II is 25 kPa.

[0060] Another embodiment is different in that, in the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, the liquid level of the absorption tower II is 1300 mm; the pressure of the absorption tower II is 40 kPa.

[0061] In the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, after the ion exchange resin in the resin tower in the solution desalting device reaches the working exchange capacity, it is backwashed and regenerated with a sodium hydroxide solution having a mass fraction of 3%.

[0062] Another embodiment is different in that, in the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, after the ion exchange resin in the resin tower in the solution desalting device reaches the working exchange capacity, it is backwashed and regenerated with a sodium hydroxide solution having a mass fraction of 4%.

[0063] Another embodiment is different in that, in the method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide as described above, after the ion exchange resin in the resin tower in the solution desalting device reaches the working exchange capacity, it is backwashed and regenerated with a sodium hydroxide solution having a mass fraction of 5%.

[0064] The foregoing are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A system for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide, characterized in that: The system includes Absorption Tower I, Heat Exchanger I, Gas-Liquid Separator I, Solution Filtering Device, Heat Exchanger II, Heat Exchanger III, Solution Desalting Device, Lean Solution Pump, Solution Pump, Semi-Lean Solution Pump, Normal Desorption Stripping Tower, Reboiler, Heat Exchanger IV, Gas-Liquid Separator II, Absorption Tower II, Desulfurization Tower, Rich Solution Pump, Regenerated Solution Pump, Regeneration Tank, Sulfur Foam Tank, Sulfur Foam Pump; The top outlet of Absorption Tower I is connected to the inlet of Heat Exchanger I, the outlet of Heat Exchanger I is connected to the lower inlet of Gas-Liquid Separator I, and the upper outlet of Gas-Liquid Separator I is connected to a device outside the system; the lower outlet of Absorption Tower I is connected to the upper inlet of Normal Desorption Stripping Tower, the top outlet of Normal Desorption Stripping Tower is connected to the inlet of Heat Exchanger IV, the outlet of Heat Exchanger IV is connected to the lower inlet of Gas-Liquid Separator II, the upper outlet of Gas-Liquid Separator II is connected to the top inlet of Absorption Tower II, the middle outlet of Absorption Tower II is connected to the lower inlet of Desulfurization Tower, and the upper outlet of Desulfurization Tower is connected to a device outside the system; the lower outlet of Absorption Tower II is connected to the inlet of Rich Solution Pump, the outlet of Rich Solution Pump is connected to the upper inlet of Regeneration Tank, the upper outlet of Regeneration Tank is connected to the upper inlet of Sulfur Foam Tank, the lower outlet of Sulfur Foam Tank is connected to the inlet of Sulfur Foam Pump, and the outlet of Sulfur Foam Pump is connected to a device outside the system; the lower outlet of Regeneration Tank is connected to the inlet of Regenerated Solution Pump, and the outlet of Regenerated Solution Pump is connected to the upper inlet of Absorption Tower II; the middle outlet of Normal Desorption Stripping Tower is divided into two paths and is respectively connected to the inlet of Semi-Lean Solution Pump and the inlet of Solution Pump, and the outlet of Semi-Lean Solution Pump is connected to the middle inlet of Absorption Tower I; the outlet of Solution Pump is connected to the inlet of Heat Exchanger II, the outlet of Heat Exchanger II is connected to the middle inlet of Normal Desorption Stripping Tower; the bottom outlet of Normal Desorption Stripping Tower is connected to the inlet of Heat Exchanger II, the outlet of Heat Exchanger II is connected to the inlet of Lean Solution Pump, the outlet of Lean Solution Pump is connected to the inlet of Heat Exchanger III, and the outlet of Heat Exchanger III is connected to the upper inlet of Absorption Tower I.

2. The system for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide according to claim 1, characterized in that: The Solution Filtering Device is connected in parallel to the pipeline where the outlet of Heat Exchanger II is connected to the middle inlet of Normal Desorption Stripping Tower. The Solution Filtering Device includes a Mechanical Filter, an Activated Carbon Filter, and a Precision Filter connected in sequence. The filtration accuracy of the Mechanical Filter is 25μm, and the filtration accuracy of the Precision Filter is 5μm.

3. The system for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide according to claim 1, characterized in that: The Solution Desalting Device is connected in parallel to the pipeline where the outlet of Heat Exchanger II is connected to the inlet of Lean Solution Pump. The Solution Desalting Device includes a Bag Filter and a Resin Tower connected in sequence. The Resin Tower is filled with ion exchange resin.

4. The system for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide according to claim 1, characterized in that: Heat Exchanger I, Heat Exchanger II, Heat Exchanger III, and Heat Exchanger IV are all shell-and-tube heat exchangers.

5. The system for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide according to claim 1, characterized in that: Absorption Tower I, Absorption Tower II, and Normal Desorption Stripping Tower are all packed towers.

6. A method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide, characterized in that: The method includes the following steps: (1)A mixed gas containing components such as carbon monoxide, carbon dioxide, and hydrogen sulfide enters Absorption Tower I from the lower gas-phase inlet of Absorption Tower I, and successively contacts the solution A entering Absorption Tower I from the middle liquid-phase inlet of Absorption Tower I and the solution B entering Absorption Tower I from the upper liquid-phase inlet of Absorption Tower I in a countercurrent manner. After the carbon dioxide and hydrogen sulfide in the mixed gas are absorbed by the solution A and B, a gas-liquid mixture is formed and enters the upper liquid-phase inlet of the Normal Desorption and Stripping Tower; carbon monoxide flows out from the top gas-phase outlet of Absorption Tower I, is cooled by Heat Exchanger I, and then enters Gas-Liquid Separator I. After separating trace moisture in Gas-Liquid Separator I, it is sent to a device outside the system; (2)The gas-liquid mixture entering the Normal Desorption and Stripping Tower from the upper liquid-phase inlet of the Normal Desorption and Stripping Tower moves downward. The carbon dioxide and hydrogen sulfide in the gas-liquid mixture are desorbed. The carbon dioxide and hydrogen sulfide gases leave the Normal Desorption and Stripping Tower from the top gas-phase outlet of the Normal Desorption and Stripping Tower, are cooled by Heat Exchanger IV, and then enter Gas-Liquid Separator II. After separating trace moisture in Gas-Liquid Separator II, they enter Absorption Tower II from the top gas-phase inlet of Absorption Tower II and contact the solution C entering from the upper liquid-phase inlet of Absorption Tower II in the same direction. Most of the hydrogen sulfide in the mixed gas is absorbed by the solution C; carbon dioxide leaves Absorption Tower II from the middle gas-phase outlet of Absorption Tower II, and after removing trace hydrogen sulfide in the desulfurization tower, it is sent to a device outside the system; (3)The solution C that has absorbed hydrogen sulfide flows out from the bottom liquid-phase outlet of Absorption Tower II, is sent to the regeneration tank by the rich liquid pump. Hydrogen sulfide reacts with the solution C, and hydrogen sulfide is oxidized to elemental sulfur. The sulfur foam containing elemental sulfur overflows from the upper part of the regeneration tank to the sulfur foam tank, and then is sent to a device outside the system by the sulfur foam pump; the solution C that has reacted with hydrogen sulfide reacts with the oxygen in the air entering from the upper gas-phase inlet of the regeneration tank to achieve the purpose of regenerating the solution C. The regenerated solution C is sent to the upper liquid-phase inlet of Absorption Tower II by the regenerated liquid pump; (4)The solution A that has desorbed most of the carbon dioxide and hydrogen sulfide in the Normal Desorption and Stripping Tower flows out from the middle liquid-phase outlet of the Normal Desorption and Stripping Tower in two paths. One path is sent to the middle liquid-phase inlet of Absorption Tower I by the semi-lean liquid pump; One path is sent to the inlet of Heat Exchanger II by the solution pump, and exchanges heat with the solution B that has desorbed a small part of the carbon dioxide and hydrogen sulfide flowing out from the bottom liquid-phase outlet of the Normal Desorption and Stripping Tower in Heat Exchanger II; the heat-exchanged solution A is divided into two paths. One path is directly sent to the middle liquid-phase inlet of the Normal Desorption and Stripping Tower, and one path is sent to the middle liquid-phase inlet of the Normal Desorption and Stripping Tower after filtering the solid impurities in the solution A through the solution filtering device; (5)The solution B after heat exchange in Heat Exchanger II is divided into two paths. One path is directly sent to the inlet of the lean liquid pump, and one path is sent to the inlet of the lean liquid pump after removing the heat-stable salts in the solution through the solution desalting device; the solution B at the outlet of the lean liquid pump is cooled by Heat Exchanger III and then enters Absorption Tower I from the upper liquid-phase inlet of Absorption Tower I.

7. The method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide according to claim 6, characterized in that: The solution A is an MDEA solution containing 15 - 30 μL / L of carbon dioxide, the solution B is an MDEA solution containing 1 - 5 μL / L of carbon dioxide, and the solution C is a complex iron solution.

8. The method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide according to claim 6, characterized in that: The liquid level of Absorption Tower I is 1700 - 2700 mm; the pressure inside Absorption Tower I is 1.0 - 2.0 MPa, and the pressure difference between the gas phase inlet at the lower part and the gas phase outlet at the top of Absorption Tower I is 2 - 20 kPa; the temperature of the gas phase outlet at the top of Absorption Tower I is 30 - 80 °C.

9. The method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide according to claim 6, characterized in that: The liquid level at the upper part of the Normal Desorption Stripping Tower is 1800 - 2800 mm, and the liquid level at the lower part is 2200 - 3500 mm; the pressure of the Normal Desorption Stripping Tower is 10 - 80 kPa, and the pressure difference between the upper and lower parts of the Normal Desorption Stripping Tower is 0.1 - 18 kPa; the temperature at the outlet of the reboiler is 100 - 120 °C.

10. The method for efficiently separating carbon monoxide, carbon dioxide, and hydrogen sulfide according to claim 6, characterized in that: The liquid level of Absorption Tower II is 270 - 1300 mm; the pressure of Absorption Tower II is 8 - 40 kPa.

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