Method and device for purifying reducing gas from blast furnace or converter gas

Abstract

The invention discloses a method and a device for purifying reducing gas from blast furnace or converter gas. The method comprises a raw material gas pretreatment process, a CO2 gas removal process and a reducing gas CO purification process. And returning the reducing gas to a blast furnace to participate in a metal smelting reaction process or be used for synthesizing an organic chemical product. The method disclosed by the invention is beneficial to reducing carbon emission, and has the advantages of saving operation cost and being low in equipment investment, the equipment is mutually coupled, a residual pressure recovery system is utilized and transformed to recover pressure energy contained in the emptied gas, and cold energy is utilized to cool the feed gas through heat exchange, so that the production efficiency is improved. And finally, carrying out flushing desorption or vacuumizing and flushing desorption on the desorption of the pressure swing adsorption decarbonization device by taking the gas as flushing gas.

Description

Technical Field

[0001] This patent relates to a method and device for purifying reducing gas from blast furnace or converter gas, and belongs to the field of metallurgical technology. Background Art

[0002] During the production process of the metallurgical industry, a large amount of coke oven gas (coking), blast furnace gas (ironmaking) and converter gas (steelmaking) are produced, referred to as the "three gases". The smelting process of other ferrous metals and non-ferrous metals will also produce blast furnace gas, converter gas and tail gas with gas components similar to blast furnace gas and converter gas. The smelting process of other ferrous metals and non-ferrous metals is similar to the smelting process of steel. This patent takes the blast furnace and subsequent tail gas treatment process of the steel smelting process as representatives, and the treatment method and device of the process are also applicable to similar smelting processes of other ferrous metals and non-ferrous metals.

[0003] Among the "three gases" in steel plants, blast furnace gas has the lowest effective gas content, but its emissions are the largest. The main components of blast furnace gas are: CO, CO2, N2, H2, CH4, etc., of which CO content accounts for about 25%, CO2 and N2 content accounts for 15% and 55% respectively, and H2 and CH4 content is very small. Blast furnace gas has a low calorific value of only 3300-3800 kJ / Nm3. Since CO2 and N2 in blast furnace gas neither participate in combustion to generate heat nor support combustion, on the contrary, they also absorb a large amount of heat generated during the combustion process, resulting in a low theoretical combustion temperature of blast furnace gas, only about 1300℃. Blast furnace gas is unstable in combustion at room temperature. Generally, industrial furnaces cannot use blast furnace gas alone as fuel. It needs to be mixed with high calorific value gas such as coke oven gas or converter gas. However, the calorific value of blast furnace gas mixed with coke oven gas or converter gas fluctuates greatly, which not only puts higher requirements on the combustion device, but also affects the product quality to varying degrees. Since most companies have surplus blast furnace gas and shortage of high calorific value gas, there is a phenomenon of blast furnace gas emission to varying degrees, which not only pollutes the environment, but also wastes energy.

[0004] How to effectively utilize these blast furnace gases with low calorific value, high impurity content, huge output, difficult purification, and serious environmental pollution is a difficult problem that needs to be solved both at home and abroad. At present, blast furnace gas is generally used for combustion to release heat or generate electricity, but due to its low calorific value, high content of non-combustible components, poor combustion efficiency and utilization rate, and waste of a large amount of precious reducing gas CO that can be used for reaction, and the income generated by its combustion for heat supply or power generation is much lower than the income from using it as reducing gas CO for reaction after treatment.

[0005] my country has proposed specific goals of "carbon peak" and "carbon neutrality", and "carbon emission reduction" has risen to a strategic level. The metal smelting industry is a major carbon emitter, and the demand for "carbon emission reduction" is huge. This puts higher requirements on the metal smelting process, especially the steel smelting process.

[0006] Take blast furnace gas as an example. Currently, most steel mills use blast furnace gas for combustion, which is used for heating or power generation. Most of the combustible components in blast furnace gas are CO, which turns into CO2 after combustion, which increases carbon emissions. Purifying blast furnace gas to extract useful components to make organic chemical products (such as ethylene glycol, natural gas, etc.), or returning it to the blast furnace for metal smelting, can reduce "carbon emissions" and utilize the main useful reducing component CO in blast furnace gas and converter gas, avoiding the low-level use of them as fuel.

[0007] How to efficiently and low-costly purify the useful components of blast furnace gas and converter gas and reduce the cost of purification so as to make this process route more economical is the key to the successful implementation of this process route and is also related to the speed of advancement of the country's "carbon emission reduction" policy in the metal smelting industry. Summary of the invention

[0008] To achieve the above-mentioned purpose, the inventors, through extensive field research and years of engineering design experience, have proposed a method for treating blast furnace coal or converter gas through dust and impurity removal, dechlorination, organic sulfur conversion, desulfurization, pressure swing adsorption decarbonization and pressure swing adsorption CO separation, and injecting the resulting reducing gas into a blast furnace for metal smelting or as a raw gas for the synthesis of organic chemical products.

[0009] Through overall material and energy matching, this process not only simplifies the process flow, but also reduces equipment investment and overall energy consumption, reduces "carbon emissions", and achieves high-value utilization of blast furnace gas or converter gas.

[0010] The technical solution is:

[0011] A method for purifying reducing gas from blast furnace or converter gas comprises the following steps:

[0012] In the first step, the gas undergoes a pre-treatment process;

[0013] Step 2: Remove CO2 gas from the coal gas by pressure swing adsorption, and the volume fraction of CO2 in the obtained gas is ≤30%;

[0014] Step 3: purify the coal gas into CO gas by pressure swing adsorption method, and the volume fraction of CO in the obtained gas is ≥50%.

[0015] The coal gas mainly includes: one or two of blast furnace gas and converter gas; the coal gas also contains coke oven gas with a volume ratio of ≤30%, or a mixture of one or more of the following:

[0016] The pretreatment process described in step 1 includes: dust removal, dechlorination, organic sulfur conversion, heat exchange, and desulfurization;

[0017] The order of the pretreatment process in step 1 is: dust removal, dechlorination, organic sulfur conversion, heat exchange, and desulfurization;

[0018] The pretreatment process described in step 1 also includes: one or a combination of deoxygenation, dehydration, and CH4 removal.

[0019] In one embodiment, the volume fraction of CO obtained by the pressure swing adsorption purification of CO in step 3 is ≥ 60%.

[0020] In one embodiment, the volume fraction of CO obtained by the pressure swing adsorption purification of CO in step 3 is ≥ 70%.

[0021] In one embodiment, the volume fraction of CO obtained by the pressure swing adsorption purification of CO in step 3 is ≥ 75%.

[0022] In one embodiment, the volume fraction of CO obtained by the pressure swing adsorption purification of CO in step 3 is ≥ 80%.

[0023] In one embodiment, the volume fraction of CO obtained by the pressure swing adsorption purification of CO in step 3 is ≥ 85%.

[0024] In one embodiment, the volume fraction of CO obtained by the pressure swing adsorption purification of CO in step 3 is ≥ 90%.

[0025] In one embodiment, the volume fraction of CO obtained by the pressure swing adsorption purification of CO in step 3 is ≥ 95%.

[0026] In one embodiment, the volume fraction of CO obtained by the pressure swing adsorption purification of CO in step 3 is ≥ 98%.

[0027] In one embodiment, the volume fraction of CO obtained by the pressure swing adsorption purification of CO in step 3 is ≥ 98.5%.

[0028] In one embodiment, the volume fraction of CO obtained by the pressure swing adsorption purification of CO in step 3 is ≥ 99%.

[0029] In one embodiment, the volume fraction of CO obtained by the pressure swing adsorption purification of CO in step 3 is ≥ 99.5%.

[0030] In one embodiment, the volume fraction of CO2 in the gas obtained by removing CO2 by the pressure swing adsorption method in step 2 is ≤30%.

[0031] In one embodiment, the volume fraction of CO2 in the gas obtained by removing CO2 by the pressure swing adsorption method in step 2 is ≤25%.

[0032] In one embodiment, the volume fraction of CO2 in the gas obtained by removing CO2 by the pressure swing adsorption method in step 2 is ≤20%.

[0033] In one embodiment, the volume fraction of CO2 in the gas obtained by removing CO2 by the pressure swing adsorption method in step 2 is ≤15%.

[0034] In one embodiment, the volume fraction of CO2 in the gas obtained by removing CO2 by the pressure swing adsorption method in step 2 is ≤10%.

[0035] In one embodiment, the volume fraction of CO2 in the gas obtained by removing CO2 by the pressure swing adsorption method in step 2 is ≤5%.

[0036] In one embodiment, the volume fraction of CO2 in the gas obtained by removing CO2 by the pressure swing adsorption method in step 2 is ≤2%.

[0037] In one embodiment, the volume fraction of CO2 in the gas obtained by removing CO2 by the pressure swing adsorption method in step 2 is ≤1%.

[0038] In one embodiment, the volume fraction of CO2 in the gas obtained by removing CO2 by the pressure swing adsorption method in step 2 is ≤0.5%.

[0039] In one embodiment, the volume fraction of CO2 in the gas obtained by removing CO2 by the pressure swing adsorption method in step 2 is ≤0.2%.

[0040] In one embodiment, the volume fraction of CO2 in the gas obtained by removing CO2 by the pressure swing adsorption method in step 2 is ≤0.1%.

[0041] In one embodiment, the weakly adsorbed component gas coming out of the top of the adsorption tower of the pressure swing adsorption CO purification device described in step 3 is the flushing tail gas, and the flushing tail gas first passes through a residual pressure recovery device (TRT) to recover pressure energy for power generation or external work.

[0042] In one embodiment, the flushing tail gas with a low temperature and slightly higher than normal pressure obtained after recovering pressure energy through the residual pressure recovery device (TRT) is heat exchanged in heat exchanger A with the gas converted through the organic sulfur conversion device.

[0043] In one embodiment, the flushing tail gas heated by heat exchange in heat exchanger A is used as flushing gas to flush and desorb or vacuum and flush and desorb the pressure swing adsorption decarbonization device. The pressure swing adsorption decarbonization device adopts at least one of vacuum desorption, flushing desorption, and vacuum and flushing desorption.

[0044] In one embodiment, the desorption process of the pressure swing adsorption decarbonation device is to desorb CO2 or to desorb CO2 and desorb gaseous water simultaneously.

[0045] In one embodiment, the organic sulfur conversion step is performed by a catalytic hydrogenation reaction method or a catalytic hydrolysis reaction method;

[0046] In one embodiment, the organic sulfur conversion step is located upstream of the desulfurization step;

[0047] In one embodiment, the deoxygenation is carried out by a catalytic reaction method;

[0048] In one embodiment, the CH4 is removed by a catalytic combustion method;

[0049] In one embodiment, the deoxygenation and CH4 removal are located on the upstream side of the CO2 removal step and on the downstream side of the dechlorination step;

[0050] In one embodiment, the dust removal step is performed by filtration and / or temperature swing adsorption method;

[0051] In one embodiment, the dechlorination step is performed by an adsorbent or water washing or alkaline washing method;

[0052] In one embodiment, the dehydration step is located before the CO purification step and after the hydrolysis step;

[0053] In one embodiment, the heat exchange step includes heat exchanger A and heat exchanger B, and heat exchanger B is water-cooled for heat exchange.

[0054] In one embodiment, the heat exchange step is located after the organic sulfur conversion step and before the desulfurization step.

[0055] In one embodiment, the desulfurization step includes a rough desulfurization unit and a fine desulfurization unit.

[0056] A device for purifying reducing gas from blast furnace or converter gas, comprising:

[0057] A pre-treatment device, the inlet of the pre-treatment device is connected to the outlet of the gas mainly including blast furnace gas and / or converter gas;

[0058] The pressure swing adsorption decarbonization device is a device for removing CO2 by pressure swing adsorption. The inlet of the pressure swing adsorption decarbonization device is connected to the outlet of the pretreatment device;

[0059] A pressure swing adsorption CO purification device, wherein the inlet of the pressure swing adsorption CO purification device is connected to the outlet of the weakly adsorbed component of the pressure swing adsorption decarbonization device;

[0060] In one embodiment, the inlet mainly containing blast furnace gas and / or converter gas is also connected to an inlet for coke oven gas, other tail gas or purge gas.

[0061] In one embodiment, the pretreatment device includes: a dust removal device, a dechlorination device, an organic sulfur conversion device, a heat exchange device, and a desulfurization device.

[0062] In one embodiment, the pretreatment process further includes: a deoxygenation device, a dehydration device, and a CH4 removal device, or a combination of several of them.

[0063] In one embodiment, in the pretreatment device: the inlet of the dust removal device is the inlet of the pretreatment device, the outlet of the dust removal device is connected to the inlet of the dechlorination device, the outlet of the dechlorination device is connected to the inlet of the organic sulfur conversion device, the outlet of the organic sulfur conversion device is connected to the inlet of the hot fluid end of the heat exchange device, and the outlet of the hot fluid end of the heat exchange device is connected to the inlet of the desulfurization device.

[0064] In one embodiment, the device for purifying reducing gas from blast furnace or converter gas comprises:

[0065] The inlet of the residual pressure recovery device (TRT) is connected to the outlet of the weakly adsorbed component of the pressure swing adsorption CO purification device, and the residual pressure recovery device (TRT) is used for power generation or external work.

[0066] In one embodiment, the device for purifying reducing gas from blast furnace or converter gas comprises:

[0067] Heat exchanger A, the cold fluid inlet of heat exchanger A is connected to the outlet of the residual pressure recovery device (TRT), and the cold fluid outlet of heat exchanger A is connected to the flushing gas inlet of the weak adsorption component end of the pressure swing adsorption decarbonization device.

[0068] In one embodiment, the organic sulfur conversion device is a catalytic hydrogenation reaction device or a catalytic hydrolysis reaction device.

[0069] In one embodiment, the organic sulfur conversion device is located on the upstream side of the desulfurization device.

[0070] In one embodiment, the deoxygenation device is a catalytic reaction deoxygenation device.

[0071] In one embodiment, the CH4 removal device is a catalytic combustion CH4 removal device.

[0072] In one embodiment, the deoxygenation device and the CH4 removal device are located on the upstream side of the pressure swing adsorption decarbonation device and on the downstream side of the dechlorination device.

[0073] In one embodiment, the dust removal device is a filtering device and / or a temperature variable adsorption device.

[0074] In one embodiment, the dechlorination device is an adsorption dechlorination device, a water washing dechlorination device, or an alkali solution dechlorination device.

[0075] In one embodiment, the dehydration device is located before the CO purification device and after the organic sulfur conversion device.

[0076] In one embodiment, the heat exchange device includes a heat exchanger A and a heat exchanger B, and the heat exchanger B is a water-cooled heat exchanger.

[0077] In one embodiment, the heat exchange device is located after the organic sulfur conversion device and before the desulfurization device.

[0078] In one embodiment, the desulfurization device includes a rough desulfurization device and a fine desulfurization device.

[0079] For different combinations, it is obvious that the pressure swing adsorption device is connected to the tail of the pretreatment device (that is, after the last unit of the pretreatment device is completed).

[0080] The names of the pressure swing adsorption devices involved in this patent also include some functional names such as pressure swing adsorption CO purification device, pressure swing adsorption decarbonization device, etc., which are all for the purpose of clearly describing this patent rather than mainly limiting the structure.

[0081] Beneficial effects:

[0082] At present, the common utilization methods of blast furnace gas and converter gas in factories are as fuel or power generation (power generation also requires combustion and heat release first). They all utilize the heat energy released by combustion (i.e. the process of CO burning into CO2), but this is an inefficient utilization method and will emit CO2 after combustion. CO is a reducing component and can be used as a raw material for chemical production or metal smelting. This utilization method is an efficient and high value-added utilization method. The required heat can be provided by burning natural gas. Since natural gas is mainly methane, the C / H ratio is low, and the amount of CO2 produced by combustion per unit of heat is small, which can achieve "carbon emission reduction".

[0083] Some people have proposed to purify blast furnace gas and converter gas to extract useful components to make organic chemical products (such as ethylene glycol, natural gas, etc.), but this has not been actually implemented in reality. The main reason is that for the current steel plant personnel, manufacturing organic chemical products is a huge challenge in terms of knowledge system, management system, safety system, etc. The huge barriers between the two different industries of metallurgy and chemical industry make this application difficult to implement.

[0084] Compared with the technology of the existing general scheme, this patent has substantial characteristics and significant progress in that: the pressure energy of the adsorption tail is recovered for power generation; the cold energy of the tail gas is recovered through heat exchange and used to cool the feed gas, saving the amount of cooling water; the adsorption tail gas (pressure 0-0.05MPa, further 0-0.02MPa, further 0.005-0.2MPa) is used as a flushing gas to perform atmospheric pressure flushing and desorption on the pressure swing adsorption decarbonization device, saving the electric energy of the vacuum pump for vacuuming, and at the same time partially recovering the useful component CO in the adsorption tail gas, thereby improving the recovery rate of CO; the position of the temperature swing adsorption dehydration device is changed or even the temperature swing adsorption dehydration device is cancelled, thereby reducing the regeneration frequency of the temperature swing adsorption dehydration device and reducing the dehydration energy consumption of the temperature swing adsorption dehydration device.

[0085] This patent makes efficient and high value-added use of the useful reducing component CO in blast furnace gas or converter gas, and returns it to the blast furnace for metal smelting reaction by using its reducing property, making full use of its value. It also reduces the "carbon emission" in the metal smelting process of the blast furnace. It is a "carbon emission reduction" method for the metal smelting industry with small investment and fast results, which optimizes the process flow and reduces equipment investment and overall energy consumption.

[0086] This patent utilizes the useful component CO in blast furnace gas or converter gas as raw gas for organic synthesis in an efficient and high value-added manner.

[0087] This patent has the advantages of saving energy and improving the recovery rate of the useful component CO.

[0088] The scheme of this patent has more advantages than the general scheme: first, the pressure swing adsorption purification CO device adsorption tower (generally -60 ℃ ~ 150 ℃, further 0 ℃ ~ 100 ℃, further 20 ℃ ~ 80 ℃, further 30 ℃ ~ 50 ℃) (the adsorption pressure is generally 0 ~ 5MPa, further 0.1 ~ 1MPa, further 0.2 ~ 0.7MPa) The weakly adsorbed component gas at the top of the tower (named flushing tail gas) is first recovered by the residual pressure recovery device (TRT) to generate electricity and also reduce the temperature at the same time, and is used as high-quality cold to heat the gas that needs to be cooled after the hydrolysis reaction (generally 30 ℃ ~ 450 ℃, further 70 ℃ ~ 280 ℃) (0.02 ~ 10MPa, further 0 .2~1.8MPa, further 0.2~1MPa, further 0.3~0.7MPa), and at the same time, it also heats up to about 40℃ (generally -60℃~150℃, further 0℃~100℃, further 20℃~80℃, further 30℃~50℃) to facilitate the flushing and desorption of the pressure swing adsorption decarbonization device, and water cooling heat exchange (0.02~10MPa, further 0.2~1.8MPa, further 0.2~1MPa, further 0.3~0.7MPa) makes up for the insufficient cold capacity and cools to about 40℃ (generally -60℃~150℃, further 0℃~100℃, further 20℃~80℃, further 30℃~50℃). This process not only recovers the pressure energy of the flushing tail gas, but also recovers the cold energy of the flushing tail gas, and at the same time completes the cooling of the gas that needs to be cooled before adsorption, achieving three goals in one go. After the cooling adsorption is completed, the adsorption tail gas mainly containing nitrogen is used as a flushing gas (pressure is generally 0-0.05MPa, further 0-0.02MPa, further 0.005-0.2MPa) to flush and desorb the pressure swing adsorption decarbonization device, which can reduce the energy consumption of the vacuum pump for vacuuming, thereby saving the power energy of the vacuum pump, that is, saving the operating cost of the device. The adsorption tail gas after adsorption mainly contains nitrogen, but also contains about 3% of CO components (0-10%, further 0-5%, further 2-5%, further 2-4%). ​​Although CO is a weakly adsorbed component relative to CO2 on the adsorbent of the pressure swing adsorption decarbonization device, CO still has a large adsorption amount on the adsorbent of the decarbonization device, and nitrogen also has a certain adsorption amount on the adsorbent of the decarbonization device. Using the adsorption tail gas to flush and desorb the pressure swing adsorption decarbonization device at normal pressure can desorb the saturated CO2 adsorbed on the adsorbent. The flushed gas mainly contains nitrogen, CO2, a small amount of CO and other impurity gases.At the same time, most of the CO contained in the adsorbed tail gas is adsorbed on the adsorbent of the pressure swing adsorption decarbonization device, and a small part of the nitrogen is also adsorbed again on the adsorbent of the decarbonization device. When the adsorption tower of the pressure swing adsorption decarbonization device enters the adsorption step again, the CO and nitrogen originally adsorbed on the adsorbent in the adsorption tower of the adsorption decarbonization device will be blown out from the top of the tower by the airflow again and enter the next step of the pressure swing adsorption CO purification device (generally 0℃~100℃, further 20℃~80℃, further 30℃~50℃) (generally 0~5MPa, further 0.1~1MPa, further 0.2~0.7MPa). In the adsorption tower of the pressure swing adsorption CO purification device, CO will be adsorbed again as an adsorption component, and nitrogen will flow out from the top of the tower as a weakly adsorbed component, and the re-adsorbed CO will be vacuumed and desorbed as product CO for the reducing gas injected into the blast furnace or as a raw gas for synthesizing organic products. The tail gas after adsorption by the CO purification device - flushing tail gas is used as flushing gas to flush and desorb the pressure swing adsorption decarbonization device (generally 0℃~100℃, further 20℃~80℃, further 30℃~50℃) (generally 0~5MPa, further 0.1~1MPa, further 0.2~0.7MPa), which solves the problem of the source of the flushing gas (that is, it mainly contains nitrogen, and nitrogen can be used as a weakly adsorbed component with no use) and reduces the energy consumption of vacuuming, saving energy. At the same time, after a series of cycles of CO adsorption, blowing and desorption in the above two devices, most of the CO lost at the top of the tower is recovered, thereby improving the recovery rate of CO. Too high water content will affect the adsorbent of the pressure swing adsorption CO purification device. In this process scheme, the temperature swing adsorption dehydration device is placed after the pressure swing adsorption decarbonization device. Most of the water in the gas will be adsorbed on the adsorbent of the adsorption decarbonization device together with CO2, and desorbed along with the desorption process of CO2. A small part of the water in the gas will be removed in the subsequent temperature swing adsorption dehydration device (generally 10℃~500℃, further 20℃~400℃, further 30℃~300℃, further 30℃~200℃) (generally 0~5MPa, further 0.1~1MPa, further 0.2~0.7MPa) to a water content below the water dew point of -40℃. This can reduce the regeneration frequency of the temperature swing adsorption dehydration device and reduce the dehydration energy consumption of the temperature swing adsorption dehydration device.

[0089] If there are any missing devices for marking temperature and pressure in the process of this patent, they can be inferred from the upstream and downstream devices. Before the devices that change the temperature and pressure appear, the temperature drop and pressure drop along the process are the heat dissipation and internal resistance of the equipment. The temperature drop and pressure drop are very small and can usually be ignored. The increase and decrease of temperature and pressure in a small section of the process of this patent, especially the increase and decrease of temperature and pressure in a small section of the process within the unit, if there are any missing markings, does not affect the integrity of the process and can be inferred from the upstream and downstream devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0090] Figure 1 It is a process flow chart for purifying reducing gas from blast furnace gas or converter gas;

[0091] Figure 2 is a process flow chart of purifying reducing gas from blast furnace gas in Example 1;

[0092] Figure 3 This is a process flow chart of purifying reducing gas from blast furnace gas in Comparative Example 1;

[0093] Figure 4 is a process flow chart of purifying reducing gas from blast furnace gas in Example 2;

[0094] Figure 5 is a process flow chart of purifying reducing gas from blast furnace gas in Example 3;

[0095] Figure 6 This is a process flow chart of purifying reducing gas from converter gas in Example 4;

[0096] Figure 7 This is a process flow chart of purifying reducing gas from converter gas in Example 5;

[0097] Figure 8 This is a structural diagram of a blast furnace gas purification reducing gas process device; DETAILED DESCRIPTION

[0098] The production method of natural gas provided by this patent mainly utilizes blast furnace gas and converter gas as raw materials or main raw materials, and the main raw materials account for the vast majority of the components, for example: volume fraction ≥70%, ≥80%, ≥90%, and the gas may also contain coke oven gas, other tail gas or purge gas, one or a mixture of two or more.

[0099] The gas composition of the above-mentioned coal gas mainly includes: N2, H2, CO, CO2, O2, CH4, H2S, COS, etc. In some conventional blast furnace gases, its composition includes by volume percentage: N2 40-65%, H2 0.5-5%, O2 0.2-5%, CO2 10-30%, CO 10-30%, CH4 0.1-2.0%, H2S 5-1000mg, COS 0.1-1000mg.

[0100] The above raw materials such as coal gas can also be subjected to corresponding pretreatment processes such as dust removal and impurity removal by conventional methods before entering the process and equipment in this patent; there are no special restrictions on these pretreatments, and there are already certain coal gas treatment devices in steel mills for dehydration, dust removal, impurity removal and other treatments. These devices can be regarded as auxiliary devices of the blast furnace or converter here.

[0101] A method for purifying reducing gas from blast furnace or converter gas, comprising the following steps:

[0102] In the first step, the gas undergoes a pre-treatment process;

[0103] Step 2: Remove CO2 gas from the coal gas by pressure swing adsorption, and the volume fraction of CO2 in the obtained gas is ≤30%;

[0104] Step 3: purify the CO gas by pressure swing adsorption method using the gas obtained in step 2, and the volume fraction of CO in the obtained gas is ≥50%.

[0105] The coal gas mainly includes: one or two of blast furnace gas and converter gas; the coal gas also contains coke oven gas with a volume ratio of ≤30%, or a mixture of one or more of the following:

[0106] Before the third step of purifying CO by the pressure swing adsorption separation method, it is also pretreated and CO2 is removed. The pretreatment includes: dust removal, impurity removal, phosphorus removal, arsenic removal, dechlorination, organic sulfur conversion, heat exchange, dehydration, deoxygenation, desulfurization, or one or more steps of CH4 removal. In the process of dust removal, some impurities will also be removed at the same time, so the dust removal step can also be called the dust removal and impurity removal step, and the dust removal device can also be called the dust removal and impurity removal device. The content of harmful impurities in the purified gas is controlled at sulfide ≤1.15ppm, NH3 ≤200ppm, O2 ≤0.4%, H2O ≤200ppm, Cl + ≤0.1ppm, arsenic ≤0.1ppm, tar + dust ≤1mg / Nm 3 , naphthalene≤1mg / Nm 3 Furthermore, the harmful impurity content is controlled at sulfide ≤ 0.1ppm, Cl + ≤0.01ppm, O2≤0.2%, H2O≤2ppm.

[0107] The further desulfurization and CO2 removal are performed after the desulfurization step. This is because blast furnace gas and / or converter gas contain trace amounts of sulfur, which will have an adverse effect on subsequent adsorbents (especially adsorbents for purifying CO), and even cause them to be deactivated and shorten their service life, so they must be removed first. And because the incoming blast furnace gas and / or converter gas will have a higher initial temperature, this is conducive to the reaction speed and desulfurization effect of the metal oxide desulfurizer.

[0108] The removal of sulfur or various impurities containing sulfur can be carried out by adsorption, membrane separation, solid desulfurizer containing oxides or hydroxides of iron, manganese, zinc, copper, nickel, calcium or tin, or composite metal oxides formed therebetween, low-temperature methanol washing, propylene carbonate method, N-methylpyrrolidone method, polyethylene glycol dimethyl ether method, polyethylene glycol methyl propyl ether method, tributyl phosphate method, hot potash method, activated hot potash method, MEA method, DEA method, MDEA method, DIPA method, propylene carbonate method + DIPA, propylene carbonate method + glycolamine, sulfolane method, sulfolane + DIPA method, sulfolane + MDEA method, methanol + secondary amine method, alkyl alcohol amine solution method, and MEA method, DEA method, MDEA method, ammonia water with the addition of an activator Washing method, caustic soda method, ADA method (stretford method), tannin method, LO-CAT method, Sulferox method, Sulfint method, Konox method, Bio-SR method, naphthoquinone method (Takahax method), metal phthalocyanine method (PDS method), GV (modified arsenic alkali method), arsenic alkali method, MSQ method, Sulfolin method, EDTA method, wet oxidation method, alkali absorption method, limestone-gypsum method, ammonia method, magnesium method, ammonium phosphate fertilizer method, organic sodium acid-gypsum method, lime-magnesium method, calcium method, dry circulating fluidized bed method, zinc oxide method, urea method, complex absorption method, charged dry absorbent injection method, plasma method, electron beam method, double alkali method, alkali sulfide method, and combinations thereof. The removed sulfur is sent to the sulfur recovery system, and the sulfur in the raw gas is removed to 0.01-0.1 ppm after desulfurization. When the absorption method is adopted, if the absorbent has the ability to absorb sulfur and carbon dioxide at the same time, sulfur and carbon dioxide can be removed at the same time. When the absorption method is adopted, in order to achieve a better desulfurization effect, it is best to set up a step of fine desulfurization (for example, desulfurization using a solid desulfurizer) afterwards. Desulfurization is carried out at 0.2-10MPa, 20-700°C, in some embodiments (0.2-3MPa, 20-400°C, further 0.2-1MPa, 20-100°C, further 0.2-0.7MPa, 20-80°C, such as some metal oxide solid desulfurizers 40-280°C, absorption liquid 20-100°C). The absorption method can achieve simultaneous removal of CO2 and desulfurization. It is best to first dehydrate and remove heavy components before setting up a step of fine desulfurization using a solid desulfurizer.

[0109] When the organic sulfur in the incoming gas is too high, the organic sulfur can be converted into inorganic sulfur through catalytic hydrogenation reaction (generally 30-450°C, further 200-450°C) or catalytic hydrolysis reaction (generally 20-450°C, further 70-250°C), and then desulfurization is carried out, so that the sulfur content of the treated gas can meet the requirements. When the sulfur in the incoming gas is mainly SO2 and the content is too high, SO2 can be converted into H2S through catalytic hydrogenation reaction, and then desulfurization is carried out, so that the sulfur content of the treated gas can meet the requirements. SO2 can also be directly used for desulfurization. The catalyst for the catalytic hydrogenation reaction here can be a catalyst commonly used in the art, or can be a metal containing iron and / or copper and / or cobalt and / or manganese and / or molybdenum and / or zinc and / or aluminum and / or nickel and / or titanium and / or zirconium and / or tungsten and / or cerium and / or their oxides and / or their sulfides and / or their soluble salts and / or composite metal oxides formed therebetween as active components, with one or more of the metals of titanium, zirconium, manganese, iron, nickel, cobalt, copper, molybdenum, tungsten, zinc, cobalt, cerium and / or their oxides and silicon, rare earth, alkali metal, alkaline earth metal, transition metal oxides and / or their sulfides as auxiliary agents. The carrier is activated carbon, aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, silica gel, molecular sieve, honeycomb ceramics, monazite, honeycomb metal, metal plate, corrugated filler, corrugated plate, fiber (cloth) material and structure, braid, metal foam, ceramic foam, graphite-based foam, etc. The catalyst for the catalytic hydrolysis reaction here contains magnesium and / or lanthanum and / or barium and / or aluminum and / or titanium and / or zirconium and / or cerium and / or potassium and / or calcium and / or cobalt and / or molybdenum and / or iron and / or copper and / or manganese and / or zinc and / or nickel and / or tungsten metals and / or their oxides and / or their sulfides and / or composite metal oxides formed therebetween as active components, and one or more of titanium, zirconium, nickel, cobalt, molybdenum, cobalt, cerium metals and / or their oxides and silicon, rare earth, alkali metal, alkaline earth metal, transition metal oxides and / or their sulfides as auxiliary agents. The carrier is activated carbon, aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, silica gel, molecular sieve, honeycomb ceramics, monazite, honeycomb metal, metal plate, corrugated filler, corrugated plate, fiber (cloth) material and structure, braid, metal foam, ceramic foam, graphite-based foam, etc. The temperature and pressure range of the organic sulfur conversion process refers to the desulfurization process.

[0110] Further, the first impurity removal pretreatment also includes: removing CH4, which can be removed by catalytic oxidation. Since the temperature required for the reaction is relatively high, it is removed first, that is, removing CH4 after the desulfurization step. If desulfurization and decarbonation are separated, the removal of CH4 is arranged after desulfurization and before decarbonation, which is conducive to saving energy and heat exchange equipment, reducing equipment investment and operating costs. In one embodiment, the removal of CH4 is mainly carried out by removing methane by catalytic combustion reaction of methane at a certain temperature (80 to 1000°C, further 100 to 350°C, further 150 to 250°C) and pressure (0.1 to 10MPa, further 0.2 to 2MPa, further 0.3 to 1MPa, further 0.3 to 0.7MPa) to prevent the catalyst from losing activity. The catalyst used can be a commonly used catalyst in the art, or can be a metal containing iron and / or copper and / or cobalt and / or manganese and / or molybdenum and / or zinc and / or aluminum and / or nickel and / or chromium and / or bismuth and / or magnesium and / or titanium and / or barium and / or ruthenium and / or zirconium and / or cerium and / or lanthanum and / or platinum and / or palladium and / or gold and / or rhodium and / or calcium and / or their oxides and / or their soluble salts and / or composite metal oxides formed therefrom as active components. One or more of the metals of titanium, zirconium, manganese, iron, nickel, cobalt, copper, molybdenum, tungsten, zinc, cobalt, cerium, aluminum, chromium, bismuth, magnesium, titanium, barium, ruthenium, zirconium, cerium, lanthanum, platinum, palladium, gold, rhodium, calcium and / or their oxides and / or their soluble salts and / or composite metal oxides formed therefrom and oxides of silicon, rare earth, alkali metal, alkaline earth metal and transition metal can be used as auxiliary agents. The carrier is activated carbon, aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, silica gel, molecular sieve, honeycomb ceramics, monazite, honeycomb metal, metal plate, corrugated packing, corrugated plate, fiber (cloth) material and structure, braid, metal foam, ceramic foam, graphite-based foam, etc. After removing CH4, the content of CH4 in the raw gas is ≤0.5%, and further CH4 is ≤0.1%.

[0111] Later, if the blast furnace gas and / or converter gas contains a high oxygen content (approximately >0.4%; further >0.04%, which is greater than this value in typical gases), it will have an adverse effect on the adsorbent for purifying CO, and may even cause it to deactivate and shorten its service life. It is necessary to deoxygenate it in advance so that the O2 concentration is ≤0.4% before entering the pressure swing adsorption separation device for separating CO and nitrogen, further ≤0.2%, and further ≤5ppm; therefore, deoxygenation is performed in advance during the impurity removal pretreatment process.

[0112] Therefore, deoxygenation is arranged after desulfurization. If the desulfurization and CO2 removal steps are separated, dehydrogenation and deoxygenation are arranged after desulfurization and before CO2 removal. If there is a CH4 removal step, dehydrogenation and deoxygenation are arranged after CH4 removal and before CO2 removal. Thus, the goal is achieved in one step, there will be adsorbents and catalysts to protect the subsequent steps, reduce CO waste, reduce the impurity removal steps generated after catalytic dehydrogenation and deoxygenation, shorten the process, reduce investment and operating costs, and at the same time, because the temperature of the gas in the front is higher, it can meet the reaction temperature of catalytic dehydrogenation and deoxygenation, thereby avoiding the investment and operating costs required for heat exchange equipment caused by the need to heat up in the back. At the same time, this order of precedence also conforms to the step-by-step principle of high and low reaction temperatures, reducing the investment and operating costs of heat exchange equipment, and dehydrogenation and deoxygenation are also conducive to increasing the purity of nitrogen and obtaining industrial nitrogen that meets the standards. Of course, if the oxygen content in the incoming gas is low (≤0.1%), dehydrogenation and deoxygenation can be omitted in the pretreatment process, which will not cause rapid deactivation of the adsorbent, but will still shorten its service life. When the dehydrogenation and deoxygenation steps are added before the carbon dioxide removal step, the CO concentration in the gas is low, which is beneficial to improving the selectivity of catalytic oxidative dehydrogenation and reducing the reaction of CO with oxygen, thereby reducing CO waste, making the reaction conditions less harsh, and facilitating the selection of catalysts. The temperature for removing O2 by catalytic oxidation is ≥30°C (further ≥50°C, and further ≥100°C).

[0113] Deoxidation can be carried out by using a selective deoxidation catalyst to simultaneously remove H2 and O2 from blast furnace gas under a pressure of 0.1 to 10 MPa (in some embodiments, 0.2 to 3 MPa, further 0.2 to 1 MPa, and further 0.3 to 0.7 MPa) and a temperature of 20 to 1000° C. (in some embodiments, 30 to 250° C., and further 50 to 160° C.). The catalyst can be a commonly used catalyst in the art, or a metal containing palladium and / or platinum and / or cobalt and / or manganese and / or copper and / or their oxides and / or sulfides as active components, and one or more of sodium, potassium, magnesium, titanium, zirconium, vanadium, manganese, iron, nickel, cobalt, copper, molybdenum, tungsten, lanthanum, zinc, silver, palladium, cobalt, or cerium and / or their oxides and / or sulfides and / or their complexes as auxiliary agents. The carrier is activated carbon, aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, silica gel, molecular sieve, honeycomb ceramic, monazite, honeycomb metal, metal plate, corrugated filler, corrugated plate, fiber (cloth) material and structure, woven fabric, metal foam, ceramic foam, graphite-based foam, etc. And as an option, since the content of O2 in the incoming gas is very low, it is not necessary to remove O2, so that the concentration of O2 before entering the pressure swing adsorption separation device for CO and nitrogen is ≤0.4%, which will not cause rapid deactivation of the adsorbent and catalyst, but it will have a certain impact on the service life of the adsorbent.

[0114] CO2 will affect the separation effect of the step of separating CO and nitrogen by pressure swing adsorption. Since CO2 has a certain amount of adsorption on the adsorbent used in the step of separating CO and nitrogen, the separation coefficients of CO2 and CO, and CO2 and nitrogen are not high. The presence of CO2 will lead to incomplete separation of CO and nitrogen, and it is impossible to obtain high-purity CO and nitrogen. The separated CO and nitrogen gases will contain more CO2, so CO2 must be removed first. The step of removing CO2 needs to be before the step of separating CO and nitrogen. The step of removing CO2 is to enable the CO and nitrogen separation step to completely separate CO and nitrogen, and obtain high-purity CO and nitrogen respectively. At the same time, this order is also in line with the step-by-step principle of adsorption capacity and the principle of adsorbing low-content components as much as possible and reducing desorption energy consumption, reducing the loss of adsorption pressure, intermediate pressurization step and desorption step. Pressure swing adsorption can be used for the step of removing CO2 from coal gas. After decarbonization, CO2 in the raw gas is removed to Vol≤1% (further ≤0.2%, further ≤0.1%, further ≤0.01%), and CO2 removal is carried out under the conditions of 0.2-20MPa, 20-150℃ (further 0.2-1.8MPa, further 0.2-1MPa, further 0.3-0.7MPa) (further 20-80℃, further 30-50℃), and the removed carbon dioxide can be sold as a carbon dioxide product or used as a raw gas for other processes or vented after reaching the venting standard or sent to a carbon capture and carbon sequestration unit. The temperature swing adsorption method removes moisture and heavy components; the adsorbent is a molecular sieve, activated carbon, alumina, silica gel or a composite bed thereof, wherein the removed tail gas containing a large amount of carbon dioxide can enter the residual pressure recovery device to recover energy when the pressure is greater than 0.15MPa. When the required concentration of CO to be purified (CO volume fraction ≥50%, further ≥60%) is not high, a one-step method can be used to directly purify CO and remove nitrogen and CO2 at the same time. However, the separation efficiency of CO2 is not high, and the CO purity is relatively low at this time (generally about ≤90%, further ≤85%, further ≤80%, further ≤70%, and the remaining main components are CO2 and nitrogen).

[0115] After pretreatment for impurity removal (20°C to 350°C, further 30°C to 300°C, further 30°C to 250°C, further 40°C to 200°C) (0 to 5MPa, further 0.1 to 1MPa, further 0.2 to 0.7MPa), the coal gas is purified by pressure swing adsorption separation method to purify CO, which mainly separates CO and N2. Pressure swing adsorption separation method is usually used to separate CO and nitrogen. Catalysts commonly used in the art can be used, and copper-based or silver-based adsorbents or metal organic framework adsorbents (MOFs, ZIFs), metal organic polyhedrons (MOPs), covalent organic framework adsorbents can also be used. The carrier can be activated carbon, alumina, silica gel, molecular sieve, honeycomb ceramics, monazite, honeycomb metal, metal plate, corrugated filler, corrugated plate, fiber (cloth) materials and structures, woven fabrics, metal foams, ceramic foams, graphite-based foams, etc. The pressure swing adsorption separation method is used to purify CO. The adsorption pressure of the pressure swing adsorption is about 0.02-10MPa (further 0.2-1.8MPa, further 0.2-1MPa, further 0.3-0.7MPa), and the operating temperature is 0-150°C (further 20-80°C, further 30-50°C). When the pressure swing adsorption method is used to separate CO and nitrogen, it is necessary to add a temperature swing adsorption method in front of the pressure swing adsorption unit to separate and remove water and heavy components, because water and heavy components will affect the effect of the subsequent pressure swing adsorption step, will have an adverse effect on the adsorbent, will reduce the separation capacity of the pressure swing adsorption of the adsorbent, and even cause irreversible damage to the adsorbent, deteriorate the adsorbent, or even cause it to be inactivated and shorten its service life. In particular, the damage to the adsorbent for separation of CO and nitrogen is more serious, which quickly deteriorates the adsorbent, causes it to be inactivated, and cannot be used. When more than one pressure swing adsorption device is connected in series, a temperature swing adsorption separation unit is added in front of the first pressure swing adsorption separation unit. CO and nitrogen are separated by the pressure swing adsorption separation method. The obtained nitrogen can enter the residual pressure recovery system when the nitrogen pressure is greater than 0.15MPa to recover the pressure energy carried by the nitrogen. When the pressure swing adsorption method is adopted, an energy recovery device can be added to the pressure swing adsorption device to recover the pressure energy wasted in the pressure swing adsorption process while completing the pressure swing adsorption separation process.

[0116] In the above processes, such as pressure swing adsorption to purify CO, pressure swing adsorption to remove CO2, etc., a temperature swing adsorption separation unit can be added in front of the pressure swing adsorption unit to separate and remove water and some heavy components contained in the gas. When more than one set of pressure swing adsorption devices are connected in series, the temperature swing adsorption separation unit is added in front of the first set of pressure swing adsorption separation units.

[0117] In this patent, the adsorbent used in the adsorption process can be any type of adsorbent that has an adsorption effect, without special restrictions, and can be molecular sieves, activated carbon, carbon molecular sieves, activated alumina, carbon fiber, etc., as well as their mixed filling and layered filling.

[0118] Figure 1 The invention shows a better process flow of a method for purifying reducing gas from blast furnace gas or converter gas, wherein the gas, such as blast furnace gas, is sequentially subjected to dust and impurity removal, dechlorination, organic sulfur hydrolysis to convert inorganic sulfur, heat exchange and cooling, water cooling, liquid water removal in a separator, desulfurization, pressure swing adsorption decarbonization, temperature swing adsorption dehydration, and pressure swing adsorption method to purify CO, and the purified CO is pressurized and heated as a reducing gas and then fed into a blast furnace, a residual pressure recovery device (TRT), and the flushing tail gas of the non-adsorbed components at the top of the CO adsorption tower for pressure swing adsorption purification is successively recovered through the residual pressure recovery device for pressure energy, recovered through heat exchange and heating for cold energy, and used as a flushing gas to flush and desorb the pressure swing adsorption decarbonization device.

[0119] The corresponding blast furnace gas or converter gas purification reducing gas device is provided, such as Figure 8 The treatment device includes a dust removal device, a dechlorination device, an organic sulfur hydrolysis conversion device to inorganic sulfur, a heat exchange and cooling device heat exchanger A, a water-cooling device heat exchanger B, a liquid separation tank for removing liquid water, a desulfurization device, a deoxygenation device, a pressure swing adsorption decarbonization device, a temperature swing adsorption dehydration device, a pressure swing adsorption CO purification device, and a residual pressure recovery device (TRT) connected in sequence.

[0120] The outlet of the non-adsorbed component at the top of the pressure swing adsorption purification CO adsorption tower is connected to the residual pressure recovery device (TRT).

[0121] The outlet of the residual pressure recovery device (TRT) is connected to the inlet of the cold fluid end of the heat exchanger A.

[0122] The outlet of the cold fluid end of the heat exchanger A is connected to the flushing gas inlet of the weakly adsorbed component end of the pressure swing adsorption decarbonization device.

[0123] The pretreatment device is used to pretreat the coal gas raw gas, and the pretreatment device includes a dust removal device, a dechlorination device, an organic sulfur hydrolysis and conversion device for inorganic sulfur, a heat exchange and cooling device heat exchanger A, a water-cooling device heat exchanger B, a liquid separation tank for removing liquid water, and a desulfurization device, which are connected in sequence.

[0124] The inlet of the pressure swing adsorption decarbonization device is connected to the outlet of the pretreatment device, the outlet of the weakly adsorbed component of the pressure swing adsorption decarbonization device is connected to the inlet of the temperature swing adsorption dehydration device, and the outlet of the temperature swing adsorption dehydration device is connected to the inlet of the pressure swing adsorption CO purification device;

[0125] The outlet of the CO product gas purified by the pressure swing adsorption CO purification device is connected to the compressor inlet through a buffer tank.

[0126] The present invention is further explained below with reference to specific embodiments. Unless otherwise specified, the methods used in the embodiments may adopt conventional methods in the art.

[0127] Example 1

[0128] In existing blast furnaces, the blast furnace gas coming out of the blast furnace is directly burned as fuel after desulfurization to provide heat for other devices. The existing blast furnace system is modified to recycle the blast furnace gas to purify the reducing gas therein, and the reducing gas mainly composed of CO is returned to the blast furnace to participate in metal smelting to reduce carbon emissions. After passing through the existing blast furnace gas treatment device, the treated blast furnace gas (160°C, 0.25MPag) is first removed by a bag filter for dust removal and impurities, and then enters the dechlorination tower (0.25MPag). The alkaline solution sprayed on the top of the tower absorbs trace amounts of chlorine, fluorine, arsenic, phosphorus, HCN and other acidic components in the blast furnace gas and finally cools down to 80°C, removing chlorine, fluorine, arsenic, phosphorus, HCN and other contents to less than 0.1ppm. The dechlorinated gas enters the hydrolysis tower (80°C, 0.25MPag), and after the organic sulfur is converted into inorganic sulfur under the action of a low-temperature hydrolysis catalyst (30-400°C, further 40-100°C, and further 70-90°C), the gas passes through a heat exchanger A (0.25MPag) for heat exchange with the flushing tail gas (-31°C, 0.02MPag). The flushing tail gas comes from the non-adsorbed components (about 40°C, 0.25MPag) at the top of the adsorption tower in the pressure swing adsorption CO purification device, which is mainly nitrogen-containing gas (-31°C, 0.02MPag) after the pressure energy is recovered by the residual pressure recovery device (TRT). After heat exchange, the gas is cooled to 49°C (0.02MPag). The gas is then cooled to 40°C (0.25MPag) by water cooling in heat exchanger B, and then the gas is passed through a separator to remove liquid water (40°C, 0.25MPag), and then the gas passes through a desulfurization unit (including coarse desulfurization and fine desulfurization) (40°C, 0.25MPag). The desulfurized gas is then removed from CO2 by a pressure swing adsorption decarbonization device. The desorption of the pressure swing adsorption decarbonization device (40°C, 0.25MPag) uses vacuum desorption in the first half (the first 1 / 2 of the desorption time), and atmospheric flushing desorption in the second half (the first 1 / 2 of the desorption time). The flushing gas is the flushing tail gas (about 40°C, 0.02MPag), which comes from the gas mainly containing nitrogen after the pressure energy is recovered by the residual pressure recovery device (TRT) and then heat exchanged to about 40°C. The gas from the pressure swing adsorption decarbonization device is then passed through a temperature swing adsorption device (40°C, 0.25MPag) to remove sufficient gaseous water, and then enters a pressure swing adsorption CO purification device (40°C, 0.25MPag) to purify CO. The purified CO gas (40°C, 0.25MPag) from vacuum desorption is used as a reducing gas, pressurized to 0.6MPag, and then heated to 900°C (generally 200°C to 2000°C, further 500°C to 1600°C, further 700°C to 1400°C, and further 900°C to 1200°C) and then sprayed into a blast furnace to reduce iron ore (iron oxide) to produce iron.The weakly adsorbed component gas at the top of the adsorption tower of the pressure swing adsorption CO purification device is used as the flushing tail gas (40℃, 0.25MPag). The flushing tail gas mainly contains nitrogen. After the flushing tail gas recovers the pressure energy through the residual pressure recovery device (TRT) (-31℃, 0.02MPag), it is heated to 40℃ (0.01MPag) through heat exchange with the hydrolyzed gas (80℃, 0.25MPag), and then used as the flushing gas to flush and desorb the second half of the desorption (the second 1 / 2 of the desorption time) of the pressure swing adsorption decarbonization device after adsorption saturation. The first half of the desorption (the first 1 / 2 of the desorption time) of the pressure swing adsorption decarbonization device (40℃, 0.25MPag) is vacuum desorbed. After flushing and desorbing, the gas is treated to purify the combustible components therein and used as combustion gas for combustion in other devices, while the non-combustible components (such as nitrogen, CO2, etc.) are discharged.

[0129] The process scheme in Example 1 has the advantages of saving energy and improving the recovery rate of the useful component CO. Compared with the general scheme such as the process of Comparative Example 1 (such as Figure 3The scheme shown in Example 1 is more advantageous: first, the weakly adsorbed component gas (40°C, 0.25MPag) at the top of the adsorption tower of the pressure swing adsorption purification CO device is first passed through the residual pressure recovery device (TRT) to recover the pressure energy for power generation and also reduce the temperature to -31°C. It is used as high-quality cooling capacity to heat the gas that needs to be cooled from 80°C to 40°C after the hydrolysis reaction. At the same time, it is also heated to about 40°C to facilitate the flushing and desorption of the pressure swing adsorption decarbonization device, and water cooling heat exchange is used to supplement the insufficient cooling capacity. This process not only recovers the pressure energy of the gas after adsorption, but also recovers the cold energy of the gas after adsorption, and at the same time completes the cooling of the gas that needs to be cooled before adsorption, achieving three goals in one fell swoop. The adsorption tail gas mainly containing nitrogen after the adsorption that has been cooled is used as a flushing gas to flush the pressure swing adsorption decarbonization device at normal pressure, which can reduce the energy consumption of the vacuum pump for vacuuming, thereby saving the power energy of the vacuum pump, that is, saving the operating cost of the device. The adsorbed tail gas after adsorption mainly contains nitrogen, but also contains about 3% (generally 2% to 5%) of CO component. Although CO is a weakly adsorbed component relative to CO2 on the adsorbent of the pressure swing adsorption decarbonization device, CO still has a considerable adsorption amount on the adsorbent of the decarbonization device, and nitrogen also has a certain adsorption amount on the adsorbent of the decarbonization device. Using the adsorbed tail gas to perform atmospheric pressure flushing and desorption on the pressure swing adsorption decarbonization device can desorb the saturated CO2 adsorbed on the adsorbent. The flushed gas mainly contains nitrogen, CO2, a small amount of CO and other impurity gases. At the same time, most of the CO contained in the adsorbed tail gas is adsorbed on the adsorbent of the pressure swing adsorption decarbonization device, and a small part of the nitrogen is also adsorbed again on the adsorbent of the decarbonization device. When the adsorption tower of the pressure swing adsorption decarbonization device enters the adsorption step again, the CO and nitrogen originally adsorbed on the adsorbent will be blown out from the top of the tower by the airflow again and enter the next step of the pressure swing adsorption CO purification device. In the adsorption tower of the pressure swing adsorption CO purification device, CO as an adsorption component will be adsorbed again, and nitrogen as a weak adsorption component will flow out from the top of the tower, and the re-adsorbed CO will be vacuumed and desorbed as product CO for the reducing gas injected into the blast furnace. The adsorbed tail gas after adsorption is used as a flushing gas to flush and desorb the pressure swing adsorption decarbonization device, which solves the problem of the source of the flushing gas (i.e., it mainly contains nitrogen, and nitrogen as a useless weak adsorption component can be used as a flushing gas), reduces the energy consumption of vacuuming, saves energy, and at the same time, through the cycle of a series of adsorption and desorption processes of the above-mentioned CO purification device and decarbonization adsorption device, most of the CO lost from the top of the purification CO adsorption tower is recovered, and the recovery rate of CO is improved.Too high water content will affect the adsorbent of the pressure swing adsorption CO purification device. In this process scheme, the temperature swing adsorption dehydration device is placed after the pressure swing adsorption decarbonization device. Most of the water in the gas will be adsorbed on the adsorbent of the adsorption decarbonization device together with CO2, and desorbed together with the desorption process of CO2. A small part of the water in the gas will be removed in the subsequent temperature swing adsorption dehydration device to a water content below the water dew point of -40℃ and then enter the pressure swing adsorption CO purification device. This can reduce the regeneration frequency of the temperature swing adsorption dehydration device and reduce the dehydration energy consumption of the temperature swing adsorption dehydration device.

[0130] Example 1 is compared with the conventional scheme such as the process of comparative example 1 (such as Figure 3 As shown): The pressure energy of the adsorption tail is recovered for power generation, producing 1Nm 3 The CO gas can recover about 0.05KWh of electricity. The cold energy of the recovered tail gas is used to cool the feed gas, thereby saving the amount of cooling water. Compared with the process of comparative example 1, about 3 / 4 of the cooling water consumption is saved. The adsorbed tail gas is used as a flushing gas to perform normal pressure flushing and desorption on the pressure swing adsorption decarbonization device, which reduces the vacuuming time and saves the electric energy of the vacuum pump for vacuuming. Compared with the process of comparative example 1, more than 1 / 2 of the vacuum pump's vacuuming energy is saved. At the same time, the useful component CO in the adsorbed tail gas is partially recovered, and the CO recovery rate is increased. Compared with the process of comparative example 1, the CO recovery rate is increased by about 1%. The position of the temperature swing adsorption dehydration device is changed to reduce the regeneration frequency of the temperature swing adsorption dehydration device and the dehydration energy consumption of the temperature swing adsorption dehydration device; the regeneration frequency is reduced by at least 20 times, and the dehydration energy consumption is also reduced by at least 20 times. At the market price of about 1Nm 3 Nitrogen is about 0.5 yuan, 1Nm 3 The hydrogen is about 1.2 yuan, in this case 1Nm 3 The CO2 flushing gas is about 2Nm 3 The process in this patent solves the source problem of flushing gas, which is equivalent to 1Nm 3 The CO2 saved is 1 to 2.4 yuan, which is more than the value of CO2 itself.

[0131] In the process and reaction flow of this embodiment, not only the gas mainly containing CO is purified from the blast furnace gas, and the gas is returned to the blast furnace for metal smelting, which reduces "carbon emissions" and saves the amount of coke required for metal smelting, but also realizes the high-value utilization of blast furnace gas with a relatively small investment. In this example, the steps are simplified, the process is compact, and the steps in the process are coupled with each other, which reduces energy consumption and saves costs.

[0132] Example 1 Specific process flow is shown in Figure 2 The gas components during each step are shown in Table 1.

[0133] Table 1

[0134] composition% Blast furnace gas After decarbonation Purified CO Purification of CO adsorption tail gas <![CDATA[N2]]> 52 66.9 4.4 93 <![CDATA[H2]]> 1.5 2 0.04 2.78 <![CDATA[O2]]> 0.3 0.39 0.02 0.52 <![CDATA[CO2]]> 22 0.2 0.5 0.31 CO 24 30.29 95 3.04 <![CDATA[CH4]]> 0.2 0.22 0.04 0.35

[0135] Example 2

[0136] In existing blast furnaces, the blast furnace gas coming out of the blast furnace is directly burned as fuel after desulfurization to provide heat for other devices. The existing blast furnace system is modified to recycle the blast furnace gas and purify the reducing gas therein, and the reducing gas mainly composed of CO is returned to the blast furnace to participate in metal smelting to reduce carbon emissions. After passing through the existing blast furnace gas treatment device, the treated blast furnace gas (220℃, 0.3MPag) is first removed from the metal dust collector for dust and impurities, and then enters the dechlorination tower (220℃, 0.3MPag) where the composite dechlorination agent adsorbs trace amounts of chlorine, fluorine and other acidic components in the blast furnace gas until the content of chlorine, fluorine, HCN, etc. is less than 0.1ppm. Since the oxygen content in the raw gas is too high, deoxygenation is required. The gas passes through the deoxygenation device and is catalytically deoxidized to less than 20ppm. The deoxygenated gas enters the hydrolysis tower (220°C, 0.3MPag). Under the action of the medium-temperature hydrolysis catalyst (30-400°C, further 100-400°C, and further 130-200°C), the organic sulfur is converted into inorganic sulfur. The gas is then cooled to 69°C (0.3MPag) by water cooling in the heat exchanger B. The gas is then heat exchanged with the flushing tail gas (-51°C, 0.005MPag) by the heat exchanger A. The flushing tail gas comes from the non-adsorbed components (about 32°C, 0.3MPag) at the top of the adsorption tower in the pressure swing adsorption device for purifying CO. The gas is mainly nitrogen-containing gas (-51°C, 0.005MPag) after the pressure energy is recovered by the residual pressure recovery device (TRT). After heat exchange, the gas is cooled to 32°C (0.3MPag). After that, the gas passes through the separator to remove liquid water (32°C, 0.3MPag), and then the gas passes through the desulfurization unit (including the rough desulfurization unit and the fine desulfurization unit) (32°C, 0.3MPag). The desulfurized gas is then removed from CO2 by the pressure swing adsorption decarbonization device. The desorption of the pressure swing adsorption decarbonization device (32°C, 0.3MPag) adopts vacuum desorption in the first half (the first 1 / 3 of the desorption time), and vacuum and flushing desorption in the second half (the last 2 / 3 of the desorption time). The flushing gas is the flushing tail gas (about 32°C, 0.005MPag). The flushing tail gas comes from the gas containing nitrogen that is mainly heat-exchanged to 32°C after the pressure energy is recovered by the residual pressure recovery device (TRT) for power generation. The gas that has passed the pressure swing adsorption decarbonization device enters the pressure swing adsorption CO purification device (32°C, 0.3MPag) to purify CO. Purified CO gas (32°C, 0.3MPag) with a purity of ≥80% by vacuum desorption is used as reducing gas, which is pressurized to 0.8MPag, heated to 950°C, and then sprayed into a blast furnace to reduce iron ore (iron oxide) to produce iron.The weakly adsorbed component gas at the top of the adsorption tower of the pressure swing adsorption CO purification device is used as the flushing tail gas (32°C, 0.3MPag). The flushing tail gas mainly contains nitrogen. After the flushing tail gas recovers the pressure energy through the residual pressure recovery device (TRT) (-51°C, 0.005MPag), it is heated to 32°C (0.005MPag) through heat exchange with the gas after water cooling (69°C, 0.3MPag), and then used as the flushing gas to flush and desorb the pressure swing adsorption decarbonization device after adsorption saturation. The gas after flushing and desorption is mixed with the combustible gas obtained from other sources as a combustible gas and then supplied to the outside. The combustible components in the gas after flushing and desorption are burned as combustion gas to provide heat.

[0137] The difference between the process scheme in Example 2 and the process scheme in Example 1 is as follows: Since the oxygen content in the raw gas (oxygen content is 1%) is relatively high (> 0.4%), a deoxygenation device needs to be added, and a medium-temperature dechlorination agent, a medium-temperature deoxygenation catalyst, and a medium-temperature hydrolysis catalyst are used under the condition of 220°C; water cooling is first adopted (heat exchanger B) and then heat exchange with the flushing tail gas (heat exchanger A, heat exchange and cooling to 32°C); the pressure swing adsorption decarbonization device removes CO2 and also dehydrates, and the desorption method and desorption process used in this embodiment make the desorption The attachment is more thorough, so the water content of the gas passing through the top of the tower reaches below the dew point of -40°C, so there is no need to add a temperature swing adsorption dehydration device, saving investment costs and reducing the dehydration energy consumption of the temperature swing adsorption dehydration device; the desorption of the pressure swing adsorption decarbonization device (32°C, 0.3MPag) adopts vacuum desorption in the first half (the first 1 / 3 of the desorption time), and vacuum and flushing desorption in the second half (the last 2 / 3 of the desorption time). Compared with the desorption method in Example 1, this desorption method has a higher energy consumption but better desorption effect.

[0138] In the process and reaction flow of this embodiment, not only the gas mainly containing CO is purified from the blast furnace gas, but also the gas is returned to the blast furnace for metal smelting, which greatly saves the amount of coke required for metal smelting. This not only reduces "carbon emissions", but also realizes the high-value utilization of blast furnace gas with relatively small investment. In this example, the steps are simplified, the process is compact, and the steps in the process are coupled with each other, which reduces energy consumption and saves costs.

[0139] Example 2 Specific process flow is shown in Figure 4 .

[0140] Example 3

[0141] After passing through the existing blast furnace gas treatment device, the treated blast furnace gas (200℃, 0.25MPag) first passes through the bag filter to remove dust and impurities, and then enters the dechlorination tower (0.25MPag). The alkaline solution sprayed on the top of the tower absorbs trace amounts of chlorine, fluorine, arsenic, phosphorus, HCN and other acidic components in the blast furnace gas and finally cools down to 80℃, removing chlorine, fluorine, arsenic, phosphorus, HCN and other contents to less than 1ppm. After dechlorination, the gas is freed of liquid water and then heated to 90°C before entering the hydrolysis tower (90°C, 0.25MPag). Under the action of the hydrolysis catalyst, the organic sulfur is converted into inorganic sulfur. The gas then passes through heat exchanger A (0.25MPa) and the flushing tail gas (-36°C, 0.02MPag) for heat exchange. The flushing tail gas comes from the non-adsorbed components at the top of the adsorption tower in the pressure swing adsorption device for purifying CO (about 40°C, 0.25MPag). The gas mainly contains nitrogen (-36°C, 0.01MPag) after the pressure energy is recovered by the residual pressure recovery device (TRT). After heat exchange, the gas is cooled to 66°C (0.01MPag). The gas is then cooled to 50°C (0.25MPag) by water cooling in heat exchanger B, and then the gas is removed from liquid water (50°C, 0.25MPag) by a separator, and then the gas is passed through a desulfurization unit (including rough desulfurization and fine desulfurization) (50°C, 0.25MPag). The gas is then passed through a temperature-swing adsorption device (50°C, 0.25MPag) to remove enough gaseous water. Since the oxygen content in the raw gas is too high, deoxygenation is required. The gas passes through a deoxygenation device and is deoxygenated to less than 5ppm after catalytic deoxygenation. The deoxygenated gas is then passed through a pressure swing adsorption decarbonization device to remove CO2. The desorption of the pressure swing adsorption decarbonization device (50°C, 0.25MPag) adopts atmospheric pressure flushing desorption in the first half (the first 1 / 2 of the desorption time), and vacuum and flushing desorption in the second half (the last 1 / 2 of the desorption time). The flushing gas is the flushing tail gas (about 20°C, 0.01MPag). The flushing tail gas comes from the gas containing mainly nitrogen after the pressure energy is recovered by the residual pressure recovery device (TRT) and then heat exchanged to 20°C. The gas that has passed through the pressure swing adsorption decarbonization device enters the pressure swing adsorption CO purification device (40°C, 0.25MPag) to purify CO. The purity of CO obtained by vacuum desorption reaches 99%, and is supplied to the synthetic ethanol device as the raw gas for organic synthesis.The weakly adsorbed component gas at the top of the adsorption tower of the pressure swing adsorption purification CO device is used as flushing tail gas (about 40℃, 0.25MPag). The flushing tail gas mainly contains nitrogen. The flushing tail gas recovers the pressure energy through the residual pressure recovery device (TRT) and is used to do work for the external (equipment) (-36℃, 0.01MPag). Then, it is heated to 20℃ (0.01MPag) by heat exchange with the hydrolyzed gas (90℃, 0.25MPag). It is then used as flushing gas to flush and desorb the pressure swing adsorption decarbonization device after adsorption saturation. The first half of the desorption (the first 1 / 2 of the desorption time) is flushed and desorbed at normal pressure, and the second half of the desorption (the last 1 / 2 of the desorption time) is vacuumed and flushed and desorbed. The gas obtained after flushing and desorption needs to be treated to meet the conditions for allowing discharge before being discharged.

[0142] The difference between the process scheme in Example 3 and the process scheme in Example 1 is as follows: the temperature of the dechlorination device and the hydrolysis device is increased to 90°C, and the reaction activity is better; the temperature is cooled to 50°C by water cooling, and the subsequent desulfurization device, temperature swing adsorption dehydration device, and deoxygenation device are all 50°C; a temperature swing adsorption dehydration device is used after the desulfurization device to remove gaseous water to 2ppm, which is beneficial to the deoxygenation process in the deoxygenation device; since the oxygen content (oxygen content is 0.7%) in the raw gas is high (>0.4%), a deoxygenation device is required, and a deoxygenation device is connected after the temperature swing adsorption dehydration device, and low-temperature catalytic deoxygenation is adopted at 50°C; the first half of the desorption of the pressure swing adsorption decarbonization device (50°C, 0.3MPag) (the first 1 / 2 of the desorption time) is atmospheric pressure flushing desorption, and the second half of the desorption (desorption) is atmospheric pressure flushing desorption. The last 1 / 2 of the attachment time) is vacuumed and flushed for desorption; during adsorption by the pressure swing adsorption decarbonization device, the temperature of the feed gas is 50°C, while the temperature of the flushing gas during desorption is 20°C. Since the adsorbent in the adsorption tower and the adsorption tower are both solid, their heat capacity is much higher than that of the gas. After heat exchange with the gas, the average temperature is 40°C, and the temperature in the adsorption tower fluctuates slightly around 40°C. This is because the pressure swing adsorption decarbonization device is not only a separation device that completes the adsorption and separation process of CO2, but also a heat exchange device that simultaneously completes the intermittent heat exchange and adsorption separation processes, which meets the temperature requirements of deoxygenation catalysis and also reduces the investment in heat exchangers, so that the gas is cooled from 50°C to 40°C; the purity of the purified CO reaches 98.5%, which is supplied to the synthetic ethanol device as the raw gas for organic synthesis.

[0143] In the process and reaction flow of this embodiment, not only the gas mainly containing CO is purified from blast furnace gas, but also the gas is used for the production of organic chemicals, which reduces the "carbon emissions" originally generated by combustion, saves the coal that needs to be consumed in the process of producing CO through coal gasification, and realizes the high-value utilization of blast furnace gas with relatively small investment. In this example, the steps are simplified, the process is compact, and the steps in the process are coupled with each other, which reduces energy consumption and saves costs.

[0144] Example 3 Specific process flow is shown in Figure 5 .

[0145] Example 4

[0146] After passing through the existing converter gas treatment device, the treated converter gas (0.02MPag, 40℃) is first dedusted and impurity-removed, and then pressurized to 0.4MPag, and then enters the dechlorination tower (0.4MPag, 90℃). The alkaline solution sprayed on the top of the tower absorbs trace amounts of chlorine, fluorine, arsenic, phosphorus, HCN and other acidic components in the converter gas and removes liquid water. Finally, the temperature is raised to 130℃, and the content of chlorine, fluorine, arsenic, phosphorus, HCN, etc. is removed to less than 10ppm. The dechlorinated gas enters a hydrolysis tower (130°C, 0.4MPag), where organic sulfur is converted into inorganic sulfur under the action of a medium-temperature multifunctional hydrolysis catalyst (30-400°C, further 100-400°C, and further 130-200°C), and oxygen is simultaneously removed to 0.05% under the action of the catalyst; the gas then passes through a heat exchanger A (0.4MPag) and a flushing tail gas (-54°C, 0.01MPag) for heat exchange, where the flushing tail gas comes from the weakly adsorbed components (about 40°C, 0.4MPag) at the top of the adsorption tower in the pressure swing adsorption device for purifying CO, and is mainly nitrogen-containing gas (-54°C, 0.01MPag) after the pressure energy is recovered by a residual pressure recovery device (TRT). After heat exchange in the heat exchanger A, the gas is cooled to 113°C (0.01MPag). The gas is then cooled to 40°C (0.4MPag) by water cooling in heat exchanger B, and then the gas is passed through a separator to remove liquid water (40°C, 0.4MPag), and then the gas passes through a desulfurization unit (including coarse desulfurization and fine desulfurization) (40°C, 0.4MPag). The desulfurized gas is then removed from CO2 by a pressure swing adsorption decarbonization device. The desorption of the pressure swing adsorption decarbonization device (40°C, 0.4MPag) uses vacuum desorption in the first 1 / 3 section (the first 1 / 3 of the desorption time), atmospheric flushing desorption in the middle 1 / 3 section (the middle 1 / 3 of the desorption time), and vacuum and flushing desorption in the last 1 / 3 section (the last 1 / 3 of the desorption time). The flushing gas is flushing tail gas (about 40°C, 0.01MPag), which comes from the gas containing mainly nitrogen after the pressure energy is recovered by the residual pressure recovery device (TRT) and then heat exchanged to 40°C. The gas after the pressure swing adsorption decarbonization unit enters the pressure swing adsorption CO purification unit (40°C, 0.4MPag) to purify the CO gas. The purity of the CO obtained by vacuum desorption reaches 98%, which is supplied to the synthetic methanol unit as the raw gas for organic synthesis.The weakly adsorbed component gas at the top of the adsorption tower of the pressure swing adsorption CO purification device is used as the flushing tail gas (40℃, 0.4MPag). The flushing tail gas mainly contains nitrogen. After the flushing tail gas passes through the residual pressure recovery device (TRT) to recover the pressure energy for power generation (-54℃, 0.01MPag), it is heated to 40℃ (0.01MPag) through heat exchange with the hydrolyzed gas (130℃, 0.4MPag), and then used as the flushing gas to flush, desorb, vacuum and flush the middle 1 / 3 section and the last 1 / 3 section of the pressure swing adsorption decarbonization device after adsorption saturation. The gas after flushing and desorption is treated to purify the combustible components therein and use them as combustion gas for combustion in other devices, while the non-combustible components (such as nitrogen, CO2, etc.) are discharged.

[0147] Under the process and reaction flow of this embodiment, the CO gas is purified from the converter gas, and is supplied to the synthetic methanol device as the raw gas for organic synthesis. This not only reduces "carbon emissions", but also achieves high-value utilization of the converter gas with a relatively small investment. In this example, the cost is saved, and at the same time, the residual pressure recovery system is used to recover the pressure energy contained in the vented gas, and its cold energy is used to cool the raw gas through heat exchange, and finally it is used as a flushing gas to flush and desorb the pressure swing adsorption decarbonization device.

[0148] Example 4 Specific process flow is shown in Figure 6 The composition of the converter gas feed is shown in Table 2.

[0149] Table 2

[0150] composition <![CDATA[N2]]> <![CDATA[H2]]> O2 <![CDATA[CO2]]> CO <![CDATA[CH4]]> sulfur Converter gas% 20 1.5 0.8 20 57.7 -- 21ppm

[0151] Example 5

[0152] Most of the process is the same as that of Example 3, except that: 1. In the step after dechlorination, a medium-temperature multifunctional hydrolysis catalyst is used to convert organic sulfur into inorganic sulfur, and catalytic deoxidation is completed at the same time, and the temperature is finally lowered to 100° C. 2. The separate deoxidation step is removed. 3. The temperature swing adsorption (TSA) dehydration step is removed. 4. The temperature of the flushing tail gas after heat exchange in heat exchanger A is 60°C, and the temperature of the incoming gas after water cooling in heat exchanger B is 30°C. Finally, during adsorption in the pressure swing adsorption decarbonization device, the temperature of the feed gas is 30°C, and the temperature of the flushing gas during desorption is 60°C. Since the adsorbent and the adsorption tower in the adsorption tower are solid, their heat capacity is much higher than that of the gas. After heat exchange with the gas, the average temperature is 40°C, and the temperature in the adsorption tower fluctuates slightly around 40°C. Here, the pressure swing adsorption decarbonization device is not only a separation device that completes the adsorption and separation process of CO2, but also a heat exchange device that simultaneously completes the intermittent heat exchange and adsorption separation process, so that the pressure swing adsorption decarbonization device adsorbs at low temperature (30°C) and desorbs at high temperature (60°C), which is more conducive to the pressure swing adsorption process and more conducive to increasing the adsorption capacity of the adsorbent.

[0153] Example 5 Specific process flow is shown in Figure 7 .

[0154] Comparative Example 1

[0155] After passing through the existing blast furnace gas treatment device, the treated blast furnace gas (160°C, 0.25MPag) first passes through the bag filter to remove dust and impurities, and then enters the dechlorination tower (0.25MPag) where the alkaline solution sprayed on the top of the tower absorbs trace chlorine in the blast furnace gas and finally cools it to 80°C. The dechlorinated gas enters the hydrolysis tower (80°C, 0.25MPag), where the organic sulfur is converted into inorganic sulfur under the action of the hydrolysis catalyst, and then the gas is cooled to 40°C (0.25MPag) by water cooling in the heat exchanger, and then the gas passes through the separator to remove liquid water (40°C, 0.25MPag), and then the gas passes through the desulfurization unit (including rough desulfurization and fine desulfurization) (40°C, 0.25MPag). The desulfurized gas is then passed through a temperature swing adsorption device (40°C, 0.25MPag) to remove enough gaseous water, and then enters a pressure swing adsorption decarbonization device to remove CO2. The desorption of the pressure swing adsorption decarbonization device (40°C, 0.25MPag) adopts vacuum desorption. The gas that has passed through the pressure swing adsorption decarbonization device enters a pressure swing adsorption CO purification device (40°C, 0.25MPag) to purify the CO gas. The purified CO gas (40°C, 0.25MPag) obtained by vacuum desorption is used as a reducing gas, which is pressurized to 0.6MPag, heated to 900°C, and then sprayed into a blast furnace to reduce iron ore (iron oxide) to produce iron.

[0156] Comparative Example 1 Specific process flow is shown in Figure 3 。

Claims

1. A method for purifying reducing gas from blast furnace or converter gas, characterized in that: The steps include: In the first step, the gas undergoes a pre-treatment process; Step 2: Remove CO2 gas from coal gas by pressure swing adsorption, and the volume fraction of CO2 in the obtained gas is ≤30%; Step 3: purify the CO gas by pressure swing adsorption method from the gas obtained in step 2, and the volume fraction of CO in the obtained gas is ≥50%; The coal gas mainly includes: one or two of blast furnace gas and converter gas; the coal gas also contains coke oven gas with a volume ratio of ≤30%, or a mixture of one or more of the purge gas; The pretreatment process described in step 1 includes: dust removal, dechlorination, organic sulfur conversion, heat exchange, and desulfurization; The order of the pretreatment process in step 1 is: dust removal, dechlorination, organic sulfur conversion, heat exchange, and desulfurization; The pretreatment process described in step 1 also includes: one or a combination of deoxygenation, dehydration, and CH4 removal.

2. The method for purifying reducing gas from blast furnace or converter gas according to claim 1, characterized in that: The weakly adsorbed component gas coming out of the top of the adsorption tower of the pressure swing adsorption CO purification device is recovered through the residual pressure recovery device and the pressure energy is used for power generation or external work.

3. The method for purifying reducing gas from blast furnace or converter gas according to claim 1, characterized in that: The low-temperature and normal-pressure gas obtained after the pressure energy is recovered by the residual pressure recovery device is heat-exchanged in heat exchanger A with the gas converted by the organic sulfur conversion device.

4. The method for purifying reducing gas from blast furnace or converter gas according to claim 1, characterized in that: The low-temperature and normal-pressure gas heated by heat exchange in heat exchanger A is used as flushing gas to flush and desorb or vacuum and flush and desorb the pressure swing adsorption decarbonization device. The desorption of the pressure swing adsorption decarbonization device adopts at least one of vacuum desorption, flushing desorption, and vacuum and flushing desorption.

5. The method for purifying reducing gas from blast furnace or converter gas according to claim 1, characterized in that: The desorption process of the pressure swing adsorption decarbonization device is to desorb CO2 or to desorb CO2 and desorb gaseous water simultaneously.

6. The method for purifying reducing gas from blast furnace or converter gas according to claim 1, characterized in that: The organic sulfur conversion step is carried out by a catalytic hydrogenation reaction method or a catalytic hydrolysis reaction method; the organic sulfur conversion step is located at the upstream side of the desulfurization step; deoxygenation is removed by a catalytic reaction method; CH4 is removed by a catalytic combustion method; deoxygenation and CH4 removal are located at the upstream side of the pressure swing adsorption decarbonization step and at the downstream side of the dechlorination step; dust removal is carried out by filtering and / or temperature swing adsorption methods; dechlorination is carried out by adsorption method or water washing method or alkaline solution washing method; the dehydration step is located before the CO purification step and after the organic sulfur conversion step; the heat exchange step includes heat exchanger A and heat exchanger B, and heat exchanger B is water-cooled for heat exchange; the heat exchange step is located after the organic sulfur conversion step and before the desulfurization step.

7. A device for purifying reducing gas from blast furnace or converter gas, characterized in that: include: A pre-treatment device, the inlet of the pre-treatment device is connected to the outlet of the gas mainly including blast furnace gas and / or converter gas; The pressure swing adsorption decarbonization device is a device for removing CO2 by pressure swing adsorption. The inlet of the pressure swing adsorption decarbonization device is connected to the outlet of the pretreatment device; A pressure swing adsorption CO purification device, wherein the inlet of the pressure swing adsorption CO purification device is connected to the outlet of the weakly adsorbed component of the pressure swing adsorption decarbonization device; The pretreatment device includes: dust removal device, dechlorination device, organic sulfur conversion device, heat exchange device, desulfurization device; The pretreatment process also includes: one or a combination of a deoxygenation device, a dehydration device, and a CH4 removal device; In the pretreatment device: the inlet of the dust removal device is the inlet of the pretreatment device, the outlet of the dust removal device is connected to the inlet of the dechlorination device, the outlet of the dechlorination device is connected to the inlet of the organic sulfur conversion device, the outlet of the organic sulfur conversion device is connected to the inlet of the hot fluid end of the heat exchange device, and the outlet of the hot fluid end of the heat exchange device is connected to the inlet of the desulfurization device.

8. The device for purifying reducing gas from blast furnace or converter gas according to claim 7, characterized in that: include: A residual pressure recovery device, the inlet of which is connected to the outlet of the weakly adsorbed component of the pressure swing adsorption CO purification device, and the residual pressure recovery device is used for power generation or external work.

9. The device for purifying reducing gas from blast furnace or converter gas according to claim 7, characterized in that: include: Heat exchanger A, the cold fluid end inlet of heat exchanger A is connected to the outlet of the residual pressure recovery device, and the cold fluid end outlet of heat exchanger A is connected to the flushing gas inlet of the weak adsorption component end of the pressure swing adsorption decarbonization device.

10. The device for purifying reducing gas from blast furnace or converter gas according to claim 7, characterized in that: The organic sulfur conversion device is a catalytic hydrogenation reaction device or a catalytic hydrolysis reaction device; The organic sulfur conversion unit is located on the upstream side of the desulfurization unit; The deoxidation device is a catalytic reaction deoxidation device; The CH4 removal device is a catalytic combustion CH4 removal device; The deoxygenation device and the CH4 removal device are located on the upstream side of the pressure swing adsorption decarbonation device and on the downstream side of the dechlorination device; The dust removal device is a filtering device and / or a temperature swing adsorption device; The dechlorination device is an adsorption dechlorination device, a water washing dechlorination device, or an alkali solution dechlorination device; The dehydration unit is located before the CO purification unit and after the organic sulfur conversion unit; The heat exchange device includes a heat exchanger A and a heat exchanger B, and the heat exchanger B is a water-cooled heat exchanger; The heat exchange device is located after the organic sulfur conversion device and before the desulfurization device.

Images