Temperature and pressure optimization system and method for hydrogen-rich carbon circulating oxygen blast furnace decarburization system

Abstract

The invention belongs to the technical field of decarburization systems, and particularly discloses a hydrogen-rich carbon circulating oxygen blast furnace decarburization system temperature and pressure optimization system and a method thereof.The hydrogen-rich carbon circulating oxygen blast furnace decarburization system temperature and pressure optimization system comprises a negative pressure flash tank and a regeneration tower, the bottom of the regeneration tower is communicated with a first semi-barren liquor pipe and a second semi-barren liquor pipe, and the first semi-barren liquor pipe is communicated with the middle section of an absorption tower; the second semi-barren liquor pipe is communicated with the top end of the negative pressure flash tank, the bottom of the negative pressure flash tank is communicated with a barren liquor pipe, the barren liquor pipe is communicated with the top end of the absorption tower, and a second cooler is arranged on the barren liquor pipe; during use, a part of generated semi-barren liquor enters the absorption tower, the other part of the generated semi-barren liquor enters the negative pressure flash tank, the barren liquor subjected to depressurization flash fully releases carbon dioxide, the temperature is reduced, and the amine liquor circulation volume in the decarbonization device can be reduced, so that the energy consumption is reduced, and the problems that the amine liquor circulation volume in a large decarbonization device is increased and the energy consumption is reduced are solved. And the scale of the corresponding cooling device is larger, so that the energy consumption is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of decarburization systems, and in particular to a temperature and pressure optimization system and method for a hydrogen-rich carbon circulating oxygen blast furnace decarburization system. Background Art

[0002] The hydrogen-rich carbon circulating oxygen blast furnace is a smelting process that uses oxygen blast instead of traditional heated air blast. Through full oxygen smelting and top gas removal of carbon dioxide and subsequent heating and recycling, it can reduce the fossil energy consumption of the iron-making process by more than 35% and the carbon emission of the process by 30%. As an important component of the hydrogen-rich carbon circulating oxygen blast furnace, the carbon dioxide removal part (hereinafter referred to as the decarbonization system) has a vital operating energy consumption for the economy of the entire hydrogen-rich carbon circulating oxygen blast furnace. At present, the operating energy consumption of the decarbonization system is above 1.8GJ / t.

[0003] The most widely used decarbonization system now is MDEA solution (amine liquid for short), which absorbs carbon dioxide in coal gas under high pressure and low temperature in the absorption tower to form a rich amine liquid (rich liquid for short) rich in carbon dioxide. The rich liquid releases carbon dioxide under low pressure and high temperature in the flash tank and regeneration tower to complete the regeneration of the amine liquid (lean liquid for short) and can be reused. During this period, the temperature rise of the amine liquid is mainly heated by steam. In order to achieve better regeneration effect in the existing decarbonization system, the temperature of the regenerated amine liquid is generally higher than 75°C, and a cooling device is required to reduce the temperature of the amine liquid to the economic operating temperature required by the absorption tower (generally controlled below 65°C). With the large-scale decarbonization device, the circulation volume of the amine liquid has increased significantly, making the scale of the cooling and temperature reduction device larger and larger, resulting in a huge waste of energy. Summary of the invention

[0004] The purpose of the present invention is to provide a temperature and pressure optimization system and method for a hydrogen-rich carbon circulating oxygen blast furnace decarburization system to solve the problem that as the circulation volume of amine liquid in a large decarburization device increases, the scale of the corresponding cooling and temperature reduction device also increases, thereby increasing energy consumption.

[0005] To achieve the above-mentioned purpose, the basic scheme provided by the present invention is: a temperature and pressure optimization system of a hydrogen-rich carbon circulating oxygen blast furnace decarbonization system, comprising a negative pressure flash tank and a regeneration tower, the bottom of the regeneration tower is connected with a semi-lean liquid pipe 1 and a semi-lean liquid pipe 2, the semi-lean liquid pipe 1 is respectively provided with a control valve 1 and a cooler 1, the semi-lean liquid pipe 1 is connected with the middle section of the absorption tower, the semi-lean liquid pipe 2 is provided with a control valve 2 and an electric heating reboiler, the semi-lean liquid pipe 2 is connected with the top of the negative pressure flash tank, the bottom of the negative pressure flash tank is connected with a lean liquid pipe, the lean liquid pipe is connected with the top of the absorption tower, the lean liquid pipe is provided with a control valve 3 and a cooler 2, the top of the negative pressure flash tank is connected with an air pipe, the air pipe is provided with an induced draft fan, and the flash tank, the regeneration tower and the air pipe are all connected to the pipe network.

[0006] The principle and beneficial effect of the present invention are as follows: when in use, the control valve 1 and the control valve 2 are opened at the same time, a part of the semi-lean liquid generated in the regeneration tower is cooled by the cooler 1 through the semi-lean liquid pipe 1 and enters the middle part of the absorption tower, and the other part enters the negative pressure flash tank through the semi-lean liquid pipe 2, the control valve 4 is opened, the control valve 3 is closed, and the semi-lean liquid circulation pipe is circulated for three times to reduce pressure and flash, and the temperature of the lean liquid after the pressure reduction and flash is reduced, which can reduce the energy consumed by the cooler 2 to reduce the temperature, the control valve 4 is closed, and the control valve 3 is opened, the lean liquid is cooled by the cooler 2 through the lean liquid pipe and enters the top of the absorption tower, the furnace top gas entering the absorption tower contacts the semi-lean liquid and the lean liquid from top to bottom in turn, and carbon dioxide is removed, the furnace top gas fully contacting with the lean liquid generates purified gas, the circulation amount of amine liquid in the decarbonization device is reduced, the lean liquid is cooled by the pressure reduction and flash, and the scale of the corresponding cooling and temperature reduction device is also reduced, thereby reducing energy consumption.

[0007] Scheme 2, which is a basic scheme, is a temperature and pressure optimization method for a hydrogen-rich carbon circulating oxygen blast furnace decarburization system, comprising the following steps:

[0008] S1. The top gas in the hydrogen-rich carbon circulating oxygen blast furnace top gas pipe enters from the bottom of the absorption tower, and contacts with the semi-lean liquid and lean liquid from top to bottom in sequence to form a purified gas that enters the purified gas pipe from the top of the absorption tower, absorbs carbon dioxide in the absorption tower to form a rich liquid rich in carbon dioxide, and the rich liquid enters the flash tank, and the flashed gas enters the pipe network, and the amine liquid after flashing enters the regeneration tower;

[0009] S2. The gas generated by the regeneration tower enters the pipe network, and the semi-lean liquid generated is divided into two parts, one part enters the middle of the absorption tower through control valve 1 and semi-lean liquid pipe 1, and the other part enters the negative pressure flash tank through control valve 2 and semi-lean liquid pipe 2;

[0010] S3. The semi-lean liquid entering the middle of the absorber is cooled by a cooler, and the semi-lean liquid entering the negative pressure flash tank is heated by an electric heating reboiler;

[0011] S4. The semi-lean liquid entering the negative pressure flash tank undergoes pressure reduction flash evaporation, and the generated gas enters the pipe network through the gas pipe and the induced draft fan, and the generated lean liquid enters the lean liquid pipe through control valve 3;

[0012] S5. The lean liquid is cooled by cooler 2 and then enters the top of the absorption tower.

[0013] After regeneration, a part of the semi-lean liquid is cooled by cooler one and then enters the middle part of the absorption tower, and the other part of the semi-lean liquid enters the negative pressure flash tank, where three negative pressure flash cycles are performed. The temperature of the generated lean liquid is reduced after the pressure is reduced, which can reduce the energy consumption of cooler two. The lean liquid is further cooled by cooler two, and after entering the top of the absorption tower, the absorption effect of carbon dioxide in the furnace top gas can be increased. The furnace top gas entering the absorption tower first contacts the semi-lean liquid in the middle part of the absorption tower from bottom to top, and after the first removal of carbon dioxide, contacts the lean liquid at the top of the absorption tower to further remove carbon dioxide, which can reduce the circulation amount of amine liquid in the decarbonization device, and at the absorption tower, the furnace top gas is subjected to two removals of carbon dioxide, which increases the decarbonization effect of the furnace top gas.

[0014] Option 3 is the preferred option of Option 2. In step S1, the pressure of the absorption tower is controlled at 1.5-1.7 MPa, and the pressure of the flash tank is controlled at 0.1-0.25 MPa. Absorbing carbon dioxide in coal gas under high pressure and low temperature can remove 20% of carbon dioxide and other hydrocarbons.

[0015] Scheme 4 is a preferred embodiment of Scheme 2. In step S2, the pressure of the regeneration tower is controlled below 20 kPa, and the temperature of the amine liquid is raised to above 80°C through a reboiler. The heated amine liquid removes more than 60% of carbon dioxide in the regeneration tower, and the resulting 80% semi-lean liquid enters semi-lean liquid pipe 1 through control valve 1, and the resulting 20% ​​semi-lean liquid enters semi-lean liquid pipe 2 through control valve 2; the semi-lean liquid generated in the regeneration tower is divided into two parts, reducing the circulation amount of amine liquid in the decarbonization device, thereby reducing energy consumption.

[0016] Scheme 5 is a preferred embodiment of Scheme 2. In step S3, the temperature of the semi-lean liquid is reduced to below 55°C by passing through a cooler 1, and the temperature of the semi-lean liquid is raised to above 80°C by passing through an electrically heated reboiler; 80% of the semi-lean liquid is cooled by cooler 1 and directly enters the middle part of the absorption tower to remove carbon dioxide, thereby reducing the circulation amount of amine liquid in the decarbonization device, thereby reducing energy consumption, and heating the semi-lean liquid entering the negative pressure flash tank to above 80°C, thereby increasing the pressure reduction flash effect of the negative pressure flash tank.

[0017] Option 6 is the preferred option of Option 2. In step S4, the pressure in the negative pressure flash tank is reduced to below -10Kpa by an induced draft fan, so that the temperature of the lean liquid is reduced to 65-70°C; the 20% semi-lean liquid entering the negative pressure flash tank is flashed to release carbon dioxide, which can reduce the temperature of the lean liquid and reduce the energy consumed by the second cooler to reduce the temperature.

[0018] Option 7 is a preferred option of Option 2. In step S5, the lean liquid passes through cooler 2 to reduce the temperature to below 55°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1It is a structural schematic diagram of a temperature and pressure optimization system and method for a hydrogen-rich carbon circulating oxygen blast furnace decarburization system of the present invention. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below through specific embodiments:

[0021] The figure marks in the drawings of the specification include: 1. absorption tower, 2. flash tank, 3. regeneration tower, 4. negative pressure flash tank, 5. hydrogen-rich carbon circulating oxygen blast furnace top gas pipe, 6. reboiler, 7. control valve one, 8. control valve two, 9. control valve three, 10. electric heating reboiler, 11. semi-lean liquid pipe one, 12. semi-lean liquid pipe two, 13. lean liquid pipe, 15. induced draft fan, 16. cooler one, 17. cooler two, 18. gas pipe, 19. pipe network, 20. purified gas pipe.

[0022] Example 1

[0023] like Figure 1 As shown: a temperature and pressure optimization system of a hydrogen-rich carbon circulating oxygen blast furnace decarbonization system, including a negative pressure flash tank 4 and a regeneration tower 3, the bottom of the regeneration tower 3 is connected with a semi-lean liquid pipe 11 and a semi-lean liquid pipe 2 12, the semi-lean liquid pipe 11 is respectively provided with a control valve 7 and a cooler 16, the semi-lean liquid pipe 11 is connected to the middle section of the absorption tower 1, the semi-lean liquid pipe 2 12 is provided with a control valve 2 8 and an electric heating reboiler 10, the semi-lean liquid pipe 2 12 is connected to the top of the negative pressure flash tank 4, the bottom of the negative pressure flash tank 4 is connected with a lean liquid pipe 13, the lean liquid pipe 13 is connected to the top of the absorption tower 1, the lean liquid pipe 13 is provided with a control valve 3 9 and a cooler 2 17, the top of the negative pressure flash tank 4 is connected with an air pipe 18, the air pipe 18 is provided with an induced draft fan 15, the flash tank 2, the regeneration tower 3 and the air pipe 18 are all connected to the pipe network 19.

[0024] The implementation method of this embodiment is as follows: when in use, the control valve 1 7 and the control valve 2 8 are opened at the same time, a part of the semi-lean liquid produced by the regeneration tower 3 is cooled through the semi-lean liquid pipe 11 and the cooler 16, and enters the middle part of the absorption tower 1, and the other part is heated by the electric heating reboiler 10 through the semi-lean liquid pipe 2 12, and then enters the negative pressure flash tank 4 for pressure reduction and flash evaporation, and then the control valve 3 9 is opened, and the lean liquid after the pressure reduction and flash evaporation is cooled through the lean liquid pipe 13 and the cooler 2 17, and enters the top of the absorption tower 1, and the top gas entering the absorption tower 1 contacts the semi-lean liquid and the lean liquid from top to bottom in turn to remove carbon dioxide, and the carbon dioxide produced by the flash tank 2, the regeneration tower 3 and the gas pipe 18 is all passed into the pipe network 19.

[0025] Example 2

[0026] like Figure 1 As shown: A temperature and pressure optimization method for a hydrogen-rich carbon circulating oxygen blast furnace decarburization system, comprising the following steps:

[0027] S1. The top gas in the hydrogen-rich carbon circulating oxygen blast furnace top gas pipe 5 enters from the bottom of the absorption tower 1, and the pressure of the absorption tower 1 is controlled at 1.5-1.7Mpa. It contacts with the semi-lean liquid and the lean liquid from top to bottom in turn to form a purified gas, which enters the purified gas pipe 20 from the top of the absorption tower 1, absorbs carbon dioxide in the absorption tower 1 to form a rich liquid rich in carbon dioxide, and the rich liquid enters the flash tank 2. The pressure of the flash tank 2 is controlled at 0.1-0.25Mpa, and the flashed gas enters the pipe network 19. The amine liquid after flashing enters the regeneration tower 3;

[0028] S2. The pressure of the regeneration tower 3 is controlled below 20 kPa, the gas generated by the regeneration tower 3 enters the pipe network 19, the temperature of the amine liquid is raised to above 80°C by the reboiler 6, and the heated amine liquid removes more than 60% of carbon dioxide in the regeneration tower 3, and the semi-lean liquid generated is divided into two parts, the 80% semi-lean liquid generated enters the semi-lean liquid pipe 11 through the control valve 7, and the 20% semi-lean liquid generated enters the semi-lean liquid pipe 12 through the control valve 8;

[0029] S3. The semi-lean liquid entering the middle of the absorber 1 is cooled by a cooler 16, the semi-lean liquid is cooled by a cooler 16 to a temperature below 55 ° C, and the semi-lean liquid entering the negative pressure flash tank 4 is heated by an electric heating reboiler 10 to raise the temperature to above 80 ° C;

[0030] S4. The semi-lean liquid entering the negative pressure flash tank 4 undergoes pressure reduction flash evaporation, and the pressure in the negative pressure flash tank 4 is reduced to below -10Kpa through the induced draft fan 15, and the temperature of the generated lean liquid is reduced to 65-70°C, and enters the lean liquid pipe 13 through the control valve 3 9, and the generated gas enters the pipe network 19 through the gas pipe 18 and the induced draft fan 15;

[0031] S5. The lean liquid is cooled by cooler 17 and then enters the top of absorption tower 1. The lean liquid is cooled by cooler 17 and its temperature is reduced to below 55°C.

[0032] The implementation method of this embodiment is as follows: the furnace top gas enters from the bottom of the absorption tower 1, and the pressure of the absorption tower 1 is controlled at 1.5-1.7Mpa. It is fully contacted with the semi-lean liquid and the lean liquid from top to bottom in turn to form a purified gas that enters the purified gas pipe 20 from the top of the absorption tower 1, which can increase the carbon dioxide absorption effect in the furnace top gas. The rich liquid enters the flash tank 2, and the pressure of the flash tank 2 is controlled at 0.1-0.25Mpa. The flashed gas enters the pipeline 19, and the amine liquid flowing out of the flash tank 2 is passed through the reboiler 6 to increase the temperature. The reboiler 6 uses the factory waste heat exchanger (the waste heat of slag washing water, the waste heat of flue gas from the gas heating furnace, etc.) for heat exchange, and uses the existing slag washing water waste heat, flue gas waste heat, coking process and other low-temperature heat sources in the steel plant to increase the temperature of the amine liquid to above 80°C, and then the amine liquid enters the regeneration tower 3 for regeneration to release carbon dioxide.

[0033] The pressure of the regeneration tower 3 is controlled below 20kpa. 80% of the semi-lean liquid after regeneration is cooled to below 55°C through a cooler 16, and then enters the middle part of the absorption tower 1. Another 20% of the semi-lean liquid enters the electric heating reboiler 10 to raise the temperature to above 80°C, and the pressure in the negative pressure flash tank 4 is reduced to below -10Kpa. The negative pressure flash tank 4 is subjected to pressure reduction flash evaporation. In this process, the lean liquid after the pressure reduction flash evaporation fully releases carbon dioxide, and the temperature is reduced to 65-70°C, which reduces the circulation amount of amine liquid in the decarbonization device and reduces the energy consumption of the cooler 17. The generated lean liquid is further cooled by the cooler 17 to below 55°C, and finally enters the top of the absorption tower 1.

[0034] The above is only an embodiment of the present invention, and the common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A temperature and pressure optimization system for a hydrogen-rich carbon cycle oxygen blast furnace decarburization system, characterized in that: The invention comprises a negative pressure flash tank (4) and a regeneration tower (3), wherein the bottom of the regeneration tower (3) is connected with a semi-lean liquid pipe 1 (11) and a semi-lean liquid pipe 2 (12), wherein the semi-lean liquid pipe 1 (11) is provided with a control valve 1 (7) and a cooler 1 (16), respectively, wherein the semi-lean liquid pipe 1 (11) is connected with the middle section of the absorption tower (1), wherein the semi-lean liquid pipe 2 (12) is provided with a control valve 2 (8) and an electric heating reboiler (10), wherein the semi-lean liquid pipe 2 (12) and the negative pressure flash tank (4) are connected to each other. The top of the negative pressure flash tank (4) is connected, the bottom of the negative pressure flash tank (4) is connected with a lean liquid pipe (13), the lean liquid pipe (13) is connected with the top of the absorption tower (1), the lean liquid pipe (13) is provided with a control valve three (9) and a cooler two (17), the top of the negative pressure flash tank (4) is connected with an air pipe (18), the air pipe (18) is provided with an induced draft fan (15), and the flash tank (2), the regeneration tower (3) and the air pipe (18) are all connected to the pipe network (19).

2. A method for optimizing the temperature and pressure of a hydrogen-rich carbon cycle oxygen blast furnace decarburization system, characterized in that , including the following steps: S1. The top gas in the hydrogen-rich carbon circulating oxygen blast furnace top gas pipe (5) enters from the bottom of the absorption tower (1), contacts with the semi-lean liquid and the lean liquid from top to bottom in sequence, forms a purified gas, and enters the purified gas pipe (20) from the top of the absorption tower (1), absorbs carbon dioxide in the absorption tower (1) to form a rich liquid rich in carbon dioxide, and the rich liquid enters the flash tank (2), the flashed gas enters the pipe network (19), and the amine liquid after flashing enters the regeneration tower (3); S2. The gas generated by the regeneration tower (3) enters the pipe network (19), and the semi-lean liquid generated is divided into two parts, one part enters the middle part of the absorption tower (1) through the control valve 1 (7) and the semi-lean liquid pipe 1 (11), and the other part enters the negative pressure flash tank (4) through the control valve 2 (8) and the semi-lean liquid pipe 2 (12); S3. The semi-lean liquid entering the middle of the absorption tower (1) is cooled by a cooler (16) and the semi-lean liquid entering the negative pressure flash tank (4) is heated by an electrically heated reboiler (10); S4. The semi-lean liquid entering the negative pressure flash tank (4) undergoes pressure reduction flash evaporation, and the generated gas enters the pipe network (19) through the gas pipe (18) and the induced draft fan (15), and the generated lean liquid enters the lean liquid pipe (13) through the control valve three (9); S5. The lean liquid is cooled in cooler 2 (17) and then enters the top of the absorption tower (1).

3. The temperature and pressure optimization method for a hydrogen-rich carbon cycle oxygen blast furnace decarburization system according to claim 2 is characterized in that: In step S1, the pressure of the absorption tower (1) is controlled at 1.5-1.7 MPa, and the pressure of the flash tank (2) is controlled at 0.1-0.25 MPa.

4. The temperature and pressure optimization method for a hydrogen-rich carbon cycle oxygen blast furnace decarburization system according to claim 2 is characterized in that: In step S2, the pressure of the regeneration tower (3) is controlled below 20 kPa, the temperature of the amine liquid is raised to above 80° C. by the reboiler (6), and more than 60% of the carbon dioxide is removed from the heated amine liquid in the regeneration tower (3). The generated 80% semi-lean liquid enters the semi-lean liquid pipe one (11) through the control valve one (7), and the generated 20% semi-lean liquid enters the semi-lean liquid pipe two (12) through the control valve two (8).

5. The temperature and pressure optimization method for a hydrogen-rich carbon cycle oxygen blast furnace decarburization system according to claim 2 is characterized in that: In step S3, the semi-lean liquid passes through a cooler (16) to reduce the temperature to below 55°C, and then passes through an electric heating reboiler (10) to increase the temperature to above 80°C.

6. The temperature and pressure optimization method for a hydrogen-rich carbon cycle oxygen blast furnace decarburization system according to claim 2 is characterized in that: In step S4, the pressure in the negative pressure flash tank (4) is reduced to below -10 KPa by the induced draft fan (15), and the temperature of the lean liquid produced by the negative pressure flash tank (4) is reduced to 65-70°C.

7. The temperature and pressure optimization method for a hydrogen-rich carbon cycle oxygen blast furnace decarburization system according to claim 2 is characterized in that: In step S5, the lean liquid passes through cooler 2 (17) to reduce the temperature to below 55°C.

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