Filtering system of absorption solution for CO2 removal system of gas-based shaft furnace

Abstract

The utility model discloses an absorption solution filtering system for a CO2 removal system of a gas-based shaft furnace. The absorption solution filtering system comprises a mechanical filter, an activated carbon filter, a carbon catcher and a centrifugal filter, an absorption solution pipeline of the CO2 removal system is communicated with an inlet of a mechanical filter through a solution filtering main valve, an outlet of the mechanical filter is communicated with an inlet of an activated carbon filter, an outlet of the activated carbon filter is communicated with an inlet of a carbon trap, and an outlet of the carbon trap is communicated with an absorption tower; the outlet of the mechanical filter is communicated with the inlet of the centrifugal filter through the stop valve; the outlet of the centrifugal filter is communicated with the absorption tower. The filtering system can effectively filter impurities and metal ions in a solution, so that stable operation of a CO2 removal system and stable and smooth operation of a shaft furnace are realized; the centrifugal filter is arranged and is started when the content of impurities in the absorption solution is high, so that the absorption effect is further improved, the impurities and the like in the absorption solution are effectively removed, and the stable operation of the CO2 removal system is ensured.

Description

Technical Field

[0001] This utility model relates to the field of gas-based vertical shaft furnace smelting technology, and in particular to a filtration system for an absorption solution used in a gas-based vertical shaft furnace CO2 removal system. Background Technology

[0002] Direct reduction technology has advantages such as low carbon emissions, clean reduction products, and high efficiency in the reduction reaction. The technology for producing direct reduced iron using gas-based shaft furnace reactors will be widely applied. Typically, the reducing gases used in gas-based shaft furnace reactors are natural gas and coke oven gas. However, regardless of whether natural gas or coke oven gas is used as raw material, CO2 gas will be generated. Since CO2 is not reducing, it needs to be removed through a CO2 removal system.

[0003] The method for CO2 removal involves using an MDEA solution as the absorbent in an absorption tower to absorb CO2. After absorbing CO2, the MDEA solution becomes a rich solution, which then enters a stripping tower for stripping, releasing CO2. The MDEA solution is then recycled for further CO2 removal. However, the MDEA solution corrodes the tower equipment during use, producing Fe. + Furthermore, process gases can introduce impurities, causing the solution to foam, and severe foaming can easily lead to flooding. Therefore, a filtration system is needed to remove Fe from the absorption solution. + Filter out impurities, etc. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a filtration system for the absorption solution of a stable gas-based vertical shaft furnace CO2 removal system.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: it includes a mechanical filter, an activated carbon filter, a carbon trap, and a centrifugal filter; the absorption solution pipeline of the CO2 removal system is connected to the inlet of the mechanical filter through a solution filtration main valve, the outlet of the mechanical filter is connected to the inlet of the activated carbon filter, the outlet of the activated carbon filter is connected to the inlet of the carbon trap, and the outlet of the carbon trap is connected to the absorption tower of the CO2 removal system; the outlet of the mechanical filter is also connected to the inlet of the centrifugal filter through a shut-off valve, and the outlet of the centrifugal filter is connected to the absorption tower of the CO2 removal system.

[0006] Furthermore, two centrifugal filters are connected in parallel, and each is equipped with a shut-off valve between it and the mechanical filter.

[0007] Furthermore, a nitrogen system is also provided; the nitrogen system is connected to the inlet and outlet of the centrifugal filter via pipeline.

[0008] Furthermore, a demineralized water system is also provided; the demineralized water system is connected to the inlet of the centrifugal filter through a pipeline.

[0009] Further, an impurity collector is provided; the impurity outlet of the centrifugal filter is communicated with the impurity collector.

[0010] Further, the mechanical filter is provided with a mechanical filter differential pressure gauge, the activated carbon filter is provided with an activated carbon filter differential pressure gauge, and the carbon trap is provided with a carbon trap differential pressure gauge.

[0011] The beneficial effects generated by the above technical scheme are that: the mechanical filter and the activated carbon filter can filter and absorb the impurities, Fe + and other metal ions in the solution, the carbon trap can filter the activated carbon in the solution, the impurities and metal ions in the solution can be effectively filtered out, the stable operation of the CO2 removal system and the stable and smooth operation of the shaft furnace can be realized; the centrifugal filter is arranged, and is started when the impurities in the absorption solution are high, the absorption effect is further improved, the impurities in the absorption solution are effectively removed, and the stable operation of the CO2 removal system is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0012] The utility model will be explained further in detail in combination with the drawings and specific embodiment.

[0013] Figure 1 It is the structure schematic diagram of the CO2 removal system of the utility model;

[0014] Figure 2 It is the structure schematic diagram of the utility model.

[0015] In the drawing: 1, filter system;2, absorption liquid temperature control system;3, absorption tower;4, absorption liquid cooler;5, cooling water filter;6, absorption liquid cooling water system;7, rich liquid filter;8, heat exchanger;9, stripping tower;10, absorption liquid filter;11, solution preparation system;12, solution filter total valve;13, absorption liquid temperature control valve;14, absorption liquid flow control valve;15, circulating pump;16, mechanical filter;17, activated carbon filter;18, carbon trap;19, 1# centrifugal filter;20, 1# impurity collector;21, 2# centrifugal filter;22, 2# impurity collector;23, 1# cut-off valve, 24, 2# cut-off valve;25, 1# water replenishing adjusting valve;26, 2# water replenishing adjusting valve;27, desalted water system;28, nitrogen system;29, mechanical filter differential pressure gauge;30, activated carbon filter differential pressure gauge;31, carbon trap differential pressure gauge. SPECIFIC EMBODIMENT

[0016] Figure 1As shown, the gas-based shaft furnace CO2 removal system comprises an absorption tower 3, an absorption liquid cooler 4, an absorption liquid cooling water system 6, a rich liquid filter 7, a heat exchanger 8, a stripping tower 9, an absorption liquid filter 10, a solution preparation system 11 and a circulating pump 15. The outlet of the solution preparation system 11 is connected to the make-up liquid inlet of the stripping tower 9, the circulating liquid outlet of the stripping tower 9 is connected to the inlet of the absorption liquid filter 10, the outlet of the absorption liquid filter 10 is connected to the inlet of one heat exchange passage of the heat exchanger 8, the outlet of the heat exchange passage of the heat exchanger 8 is connected to the inlet of one heat exchange passage of the absorption liquid cooler 4 through the circulating pump 15, the outlet of the heat exchange passage of the absorption liquid cooler 4 is connected to the inlet of the absorption tower 3, the outlet of the absorption tower 3 is connected to the inlet of the rich liquid filter 7, the outlet of the rich liquid filter 7 is connected to the inlet of another heat exchange passage of the heat exchanger 8, and the outlet of the heat exchange passage of the heat exchanger 8 is connected to the circulating liquid inlet of the stripping tower 9.

[0017] Figure 1 As shown, the gas-based shaft furnace CO2 removal system further comprises a cooling water filter 5 and an absorption liquid cooling water system 6; the absorption liquid cooling water system 6 is connected to the inlet of the cooling water filter 5, and the outlet of the cooling water filter 5 is connected to the inlet of another heat exchange passage of the liquid cooler 4.

[0018] Figure 1 As shown, the gas-based shaft furnace CO2 removal system, the pipeline between the absorption liquid cooler 4 and the absorption tower 3 is provided with an absorption liquid flow control valve 14, the pipeline between the absorption tower 3 and the rich liquid filter 7 is provided with a control valve, the pipeline between the heat exchanger 8 and the circulating liquid inlet of the stripping tower 9 is provided with a control valve, and the pipeline between the solution preparation system 11 and the stripping tower 9 is provided with a control valve. The pipeline between the absorption liquid cooler 4 and the absorption liquid flow control valve 14 is connected to the filter system 1, and a solution filter total valve 12 is arranged on the pipeline. The pipeline between the absorption liquid cooler 4 and the absorption liquid flow control valve 14 is also connected to the absorption liquid temperature control system 2, and an absorption liquid temperature control valve 13 is arranged on the pipeline, and the outlet of the absorption liquid temperature control system 2 is connected to the absorption tower 3; in this way, the temperature of the absorption liquid cooled by the absorption liquid cooler 4 is low, and the temperature is further regulated by the absorption liquid temperature control system 2, so that the temperature of the subsequent stripping tower 9 can be accurately controlled.

[0019] Figure 2As shown, the filter system for the absorption solution of the CO2 removal system of the gas-based shaft furnace comprises a mechanical filter 16, an activated carbon filter 17, a carbon trap 18 and a centrifugal filter. The absorption solution pipeline of the CO2 removal system is connected to the inlet of the mechanical filter 16 through a solution filter total valve 12, the outlet of the mechanical filter 16 is connected to the inlet of the activated carbon filter 17, the outlet of the activated carbon filter 17 is connected to the inlet of the carbon trap 18, and the outlet of the carbon trap 18 is connected to the absorption tower 3. The mechanical filter 16 is provided with a mechanical filter differential pressure gauge 29, the activated carbon filter 17 is provided with an activated carbon filter differential pressure gauge 30, and the carbon trap 18 is provided with a carbon trap differential pressure gauge 31.

[0020] Figure 2 As shown, the filter system for the absorption solution of the CO2 removal system of the gas-based shaft furnace, the outlet of the mechanical filter 16 is also connected to the inlet of the centrifugal filter, and the centrifugal filter is provided with two centrifugal filters in parallel, i.e. a first centrifugal filter 19 and a second centrifugal filter 21, one of which is used and the other is standby. The pipeline between the mechanical filter 16 and the first centrifugal filter 19 is provided with a first cut-off valve 23, and the pipeline between the mechanical filter 16 and the second centrifugal filter 21 is provided with a second cut-off valve 24. The outlets of the first centrifugal filter 19 and the second centrifugal filter 21 are both connected to the absorption tower 3. Two impurity collectors are also provided, i.e. a first impurity collector 20 and a second impurity collector 22. The impurity outlet of the first centrifugal filter 19 is connected to the first impurity collector 20, and the impurity outlet of the second centrifugal filter 21 is connected to the second impurity collector 22.

[0021] Figure 2 As shown, the filter system for the absorption solution of the CO2 removal system of the gas-based shaft furnace is also provided with a nitrogen system 28. The nitrogen system 28 is connected to the inlet and outlet of the first centrifugal filter 19 and the inlet and outlet of the second centrifugal filter 21 through pipelines, respectively.

[0022] Figure 2 As shown, the filter system for the absorption solution of the CO2 removal system of the gas-based shaft furnace is also provided with a desalted water system 27. The desalted water system 27 is connected to the inlet of the first centrifugal filter 19 through a pipeline and a first water supplementing adjusting valve 25, and is connected to the inlet of the second centrifugal filter 21 through a pipeline and a second water supplementing adjusting valve 26.

[0023] After the above structure, the carbon dioxide removal process of the carbon-based shaft furnace CO2 removal system is: the prepared absorption solution is delivered to the stripping tower 9 through the solution preparation system 11; the absorption solution is circulated by the circulating pump 15; the stripping tower 9 controls the high-temperature and low-pressure environment, which is beneficial to the release of the dissolved carbon dioxide in the absorption solution. The absorption solution discharged from the stripping tower 9 is filtered through the absorption solution filter 10 first, and then is preliminarily cooled through the heat exchanger 8, and then is further cooled in the absorption solution cooler 4. The cooled absorption solution enters the absorption tower 3 to absorb the carbon dioxide in the process gas. After absorbing the carbon dioxide in the absorption tower 3, the temperature of the absorption solution is low, and after passing through the filter 7, the absorption solution enters the heat exchanger 8 to cool the absorption solution discharged from the stripping tower 9. The cooling water is provided by the absorption solution cooling water system 6, and before cooling, the cooling water is filtered through the cooling water filter 5 to prevent the absorption solution cooler 4 from being blocked. The absorption system will be polluted due to the corrosion of the system tower and the impurities brought in by the process gas in the shaft furnace production process. When the absorption solution is seriously polluted, the absorption solution is easy to produce foam, which causes the liquid overflow accident of the absorption tower 3 and the stripping tower 9. In order to prevent this accident from happening and not to affect the production operation, therefore, in the production process, according to the pressure difference of the absorption tower 3 and the stripping tower 9, the opening degree of the solution filtering total valve 12 is controlled to control the total amount of the absorption solution in the system, and part of the absorption solution is sent to the filtering system 1 for filtering. When the pressure difference of the absorption tower is high or the pressure difference of the stripping tower is high, the opening degree of the solution filtering total valve 12 is increased. The amount of the absorption solution for absorbing carbon dioxide in the system is reduced, the opening degree of the absorption liquid flow control valve 14 is controlled to control the flow rate of the absorption solution to increase, so as to achieve the effect of stabilizing the carbon dioxide absorption efficiency. The opening degree of the absorption liquid temperature control valve 13 is controlled to control part of the low-temperature absorption solution to enter the stripping tower 9, so as to realize the temperature control of the stripping tower 9.

[0024] After the above structure, the filtering process of the absorption solution filtering system of the carbon-based shaft furnace CO2 removal system is: 1) according to the pressure difference of the absorption tower 3 and the stripping tower 9, the opening degree of the solution filtering total valve 12 is controlled. When the pressure difference of the absorption tower 3 or the stripping tower 9 is 0-2Kpa, the opening degree of the solution filtering total valve 12 is controlled to be 10-15%. When the pressure difference of the absorption tower 3 or the stripping tower 9 is 2-4Kpa, the opening degree of the solution filtering total valve 12 is controlled to be 15-30%. When the pressure difference of the absorption tower 3 or the stripping tower 9 is greater than 4Kpa, the opening degree of the solution filtering total valve 12 is kept at 30% for 0.5h, and if the pressure difference does not decrease, the defoaming agent is added to the absorption tower 3.

[0025] 2) The absorption solution that needs to be filtered enters the filtering system through the solution filtering total valve 12.

[0026] 3) First through the mechanical filter 16, the filter core of the mechanical filter 16 uses a filter core of 20μm, and filters out impurities in the solution. The working condition of the mechanical filter is monitored by the mechanical filter pressure difference table 29. When the pressure difference of the mechanical filter pressure difference table 29 is greater than 50Kpa, the mechanical filter core is replaced.

[0027] 4) After passing through the mechanical filter 16, the solution enters the activated carbon filter 17. The activated carbon filter 17 is filled with activated carbon inside, which can effectively adsorb Fe + and other metal ions in the solution. The activated carbon filter pressure difference table 30 is used to check the use of activated carbon. When the activated carbon filter pressure difference table is greater than 70Kpa, the activated carbon is replaced.

[0028] 5) After passing through the activated carbon filter 17, the solution passes through the carbon trap 18, which uses a filter core of 50μm inside, and collects the activated carbon carried out by the solution. When the pressure difference of the carbon trap pressure difference table 31 is greater than 30Kpa, the filter core is taken out and the activated carbon is recovered.

[0029] 6) The solution filtered by the mechanical filter 16 and the activated carbon filter 17 returns to the absorption tower 3.

[0030] 7) When the pressure difference of the absorption tower 3 or the stripping tower 9 is greater than 4Kpa, and the pressure difference is still rising, the 1# centrifugal filter 19 or the 2# centrifugal filter 21 is started. The centrifugal filter works in a one-use-one-backup mode.

[0031] 8) Before using the 1# centrifugal filter 19 or the 2# centrifugal filter 21, the centrifugal filter system is purged by the nitrogen system 28. To prevent oxygen from oxidizing the solution in the system, causing the absorption efficiency of the solution to decrease.

[0032] 9) After the purge is qualified, start the 1# centrifugal filter 19 or the 2# centrifugal filter 21. When the centrifugal filter is started, open the 1# water supply regulating valve 25 or the 2# water supply regulating valve 26. The desalted water system 27 provides desalted water for the centrifugal filter system.

[0033] 10) After the centrifugal filter 19 or 21 is started, when the speed reaches 2000r / min, open the 1# cut-off valve 23 or the 2# cut-off valve 24, and inject the absorption liquid into the 1# centrifugal filter 19 or the 2# centrifugal filter 21. The filtered solution returns to the absorption tower 3.

[0034] 11) The impurities filtered out by the centrifugal filter 19 or 21 are collected and treated by the 1# impurity collector 20 or the 2# impurity collector 22.

Claims

1. A filtration system for an absorption solution for a gas-based shaft furnace CO2 removal system, characterized by: The CO2 removal system comprises a mechanical filter (16), an activated carbon filter (17), a carbon trap (18) and a centrifugal filter; an absorption solution pipeline of the CO2 removal system is connected to an inlet of the mechanical filter (16) through a solution filter total valve (12), an outlet of the mechanical filter (16) is connected to an inlet of the activated carbon filter (17), an outlet of the activated carbon filter (17) is connected to an inlet of the carbon trap (18), and an outlet of the carbon trap (18) is connected to an absorption tower (3) of the CO2 removal system; the outlet of the mechanical filter (16) is also connected to an inlet of the centrifugal filter through a cut-off valve, and an outlet of the centrifugal filter is connected to the absorption tower (3) of the CO2 removal system.

2. The filtration system of an absorption solution for a gas-based shaft furnace CO2 removal system according to claim 1, characterized in that: The centrifugal filter is provided in parallel with two, and a cut-off valve is arranged between the centrifugal filter and the mechanical filter (16).

3. The filtration system for absorption solution used in a gas-based shaft furnace CO2 removal system according to claim 1, characterized in that: A nitrogen system (28) is further arranged; the nitrogen system (28) is connected to an inlet and an outlet of the centrifugal filter through a pipeline.

4. The filtration system for absorption solution used in a gas-based shaft furnace CO2 removal system according to claim 1, characterized in that: A desalted water system (27) is further arranged; the desalted water system (27) is connected to an inlet of the centrifugal filter through a pipeline.

5. The filtration system for absorption solution used in a gas-based shaft furnace CO2 removal system according to claim 1, characterized in that: An impurity collector is further arranged; an impurity outlet of the centrifugal filter is connected to the impurity collector.

6. A filtration system for absorption solution for a gas-based shaft furnace CO2 removal system according to any one of claims 1 to 5, characterized in that: The mechanical filter (16) is provided with a mechanical filter differential pressure gauge (29), the activated carbon filter (17) is provided with an activated carbon filter differential pressure gauge (30), and the carbon trap (18) is provided with a carbon trap differential pressure gauge (31).

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