Purification treatment device for coke oven gas

Abstract

The utility model discloses a purification treatment device for coke oven gas. The device comprises a pre-purification device, a compression device and a hydrodesulfurization device, and the hydrodesulfurization device is arranged at the downstream of the pre-purification device and the compression device; the pre-purification device comprises a first pretreatment tower and an adsorption tower group, the adsorption tower group is arranged at the downstream of the first pretreatment tower, the first pretreatment tower is used for removing H2S in the coke oven gas, and the adsorption tower group is used for removing tar, dust, naphthalene and part of benzene in the coke oven gas; the compression device is used for pressurizing coke oven gas; the hydrodesulfurization device comprises a hydrogenation reaction assembly and desulfurization equipment, the desulfurization equipment is arranged at the downstream of the hydrogenation reaction assembly, the hydrogenation reaction assembly is used for converting organic sulfur in the coke oven gas into inorganic sulfur, and the desulfurization equipment is used for removing the inorganic sulfur in the coke oven gas treated by the hydrogenation reaction assembly. The device can be used for effectively removing impurities in coke oven gas, so that the coke oven gas meets the quality requirement on feed gas when DRI is produced by gas-based shaft furnace ironmaking.

Description

Technical Field

[0001] The present application relates to the technical field of iron and steel metallurgy, and in particular to a purification and treatment device for coke oven gas. Background Art

[0002] Gas-based shaft furnace direct reduction iron is a process that converts iron ore into iron through solid-state reduction at a temperature below the melting point of the ore. The physical and chemical principle of gas-based direct reduction ironmaking is to use CO and H2 as reducing agents, which react with iron oxide to reduce iron ore into iron.

[0003] Coke oven gas is a byproduct of the coking industry. The H2 content in coke oven gas is as high as 50% or more, which meets the H2 content requirements of low-carbon hydrogen metallurgy in raw gas. If it is used for the production of direct reduced iron, it can reduce the pollution of the coking industry to the ecological environment. However, coke oven gas contains impurities such as sulfur, tar, naphthalene, and benzene, so it is necessary to purify the coke oven gas to meet the quality requirements of coke oven gas raw gas when producing DRI (Direct reduced iron) in gas-based vertical furnace ironmaking. Utility Model Content

[0004] The purpose of the present application is to provide a purification device for coke oven gas, which can effectively remove impurities such as sulfur, tar, naphthalene and benzene in the coke oven gas so that it meets the quality requirements for raw gas when producing DRI in gas-based vertical furnace ironmaking.

[0005] In order to solve the above technical problems, the present application provides a purification treatment device for coke oven gas, comprising a pre-purification device, a compression device and a hydrodesulfurization device, wherein the hydrodesulfurization device is placed downstream of the pre-purification device and the compression device;

[0006] The pre-purification device comprises a first pre-treatment tower and an adsorption tower group, wherein the adsorption tower group is placed downstream of the first pre-treatment tower, the first pre-treatment tower is used to remove H2S in the coke oven gas, and the adsorption tower group is used to remove tar, dust, naphthalene and part of benzene in the coke oven gas;

[0007] The compression device is used to pressurize the coke oven gas;

[0008] The hydrodesulfurization device comprises a hydrogenation reaction component and a desulfurization device, wherein the desulfurization device is placed downstream of the hydrogenation reaction component, the hydrogenation reaction component is used to convert organic sulfur in coke oven gas into inorganic sulfur, and the desulfurization device is used to remove inorganic sulfur in the coke oven gas treated by the hydrogenation reaction component.

[0009] In a feasible solution, the compression device is placed between the pre-purification device and the hydrodesulfurization device.

[0010] In a feasible solution, the compression device is a water-injected wet screw compressor.

[0011] In a feasible solution, the outlet pressure of the compression device is not less than 1.1 MPa.G.

[0012] In an achievable solution, the first pretreatment tower includes at least one desulfurization tower, and the H2S content in the coke oven gas treated by the first pretreatment tower is not higher than 20 mg / Nm 3 .

[0013] In a feasible solution, the adsorption tower group includes at least four adsorption towers, among which at least two are in the adsorption process and at least two are in the regeneration process; the naphthalene content in the coke oven gas treated by the adsorption tower group is not higher than 2 mg / Nm 3 , tar content is not higher than 2mg / Nm 3 , dust content is not higher than 2mg / Nm 3 , benzene content is not higher than 2000mg / Nm 3 .

[0014] In one feasible solution, the hydrogenation reaction assembly comprises a pre-hydrogenation reaction assembly and a primary hydrogenation reactor arranged in series; the pre-hydrogenation reaction assembly is placed upstream of the primary hydrogenation reactor, and the desulfurization equipment is placed downstream of the primary hydrogenation reactor; the hydrodesulfurization device further comprises a steam generator and a cooler arranged downstream of the primary hydrogenation reactor, and the cooler is placed downstream of the steam generator;

[0015] The desulfurization equipment includes a dry desulfurization equipment and / or a wet desulfurization equipment, wherein the dry desulfurization equipment includes a desulfurization tower placed upstream or downstream of the cooler, and the wet desulfurization equipment is placed downstream of the cooler;

[0016] The total sulfur content of the coke oven gas treated by the hydrodesulfurization device is not higher than 20 mg / Nm 3 .

[0017] In one feasible solution, the hydrodesulfurization device further comprises a heater and a heat exchanger, wherein the heater is disposed upstream of the pre-hydrogenation reaction assembly;

[0018] The heat exchanger comprises a first passage and a second passage, wherein the first passage is connected in series to the upstream of the pre-hydrogenation reaction assembly, and the second passage is connected in series to the downstream of the primary hydrogenation reactor and is arranged in parallel with the steam generator.

[0019] In one feasible solution, the pre-hydrogenation reaction assembly includes two or more pre-hydrogenation reactors arranged in parallel.

[0020] In a feasible solution, the hydrodesulfurization device further comprises a second pretreatment tower disposed upstream of the hydrogenation reaction component, and the second pretreatment tower is used to remove oil and dust from the coke oven gas flowing through the tower.

[0021] The purification treatment device provided in the embodiment of the present application pre-purifies and pressurizes the coke oven gas from the coking plant. In the pre-purification treatment, desulfurization treatment is first performed, and then tar, dust, naphthalene and benzene are removed. In the pressurization treatment, the coke oven gas is compressed, and the coke oven gas after pre-purification and pressurization treatment is subjected to hydrodesulfurization treatment. In the hydrodesulfurization treatment, hydrogenation treatment is first performed to convert organic sulfur into inorganic sulfur, and then desulfurization treatment is performed to remove inorganic sulfur. In this way, impurities such as sulfur, tar, naphthalene, dust and benzene in the coke oven gas from the coke oven plant can be effectively removed, and the content of impurities such as sulfur, tar, naphthalene, dust and benzene in the coke oven gas after purification can meet the DRI requirement for the impurity content of coke oven gas, and can be directly added to the cone section of the gas-based vertical furnace for further reforming and used as supplementary gas for reducing gas to produce gas-based vertical furnace DRI products. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A structural block diagram of an embodiment of the purification treatment device provided in this application;

[0023] Figure 2 It is a process flow chart of a pre-purification device of a purification treatment device in a specific embodiment;

[0024] Figure 3 It is a process flow chart of the hydrodesulfurization device in a specific embodiment.

[0025] Description of reference numerals:

[0026] Pre-purification device 10, desulfurization tower 11, adsorption tower group 12, first adsorption tower 12-1, second adsorption tower 12-2, third adsorption tower 12-3, fourth adsorption tower 12-4, regeneration gas heater 13, regeneration gas cooler 14, regeneration gas gas-liquid separator 15; compression device 20; hydrodesulfurization device 30, pre-hydrogenation reaction assembly 31, primary hydrogenation reactor 32, second pretreatment tower 33, heat exchanger 34, heater 35, steam generator 36, cooler 37, separator 38. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0028] Please refer to Figure 1 , Figure 1 This is a structural block diagram of an embodiment of the purification treatment device provided in this application.

[0029] The purification device provided in this embodiment is used for coke oven gas, and is mainly used to purify the coke oven gas from the coke oven plant so that the coke oven gas can meet the quality requirements of the gas-based vertical furnace for the raw gas. The coke oven gas after purification is used as the supplementary gas of the reducing gas of the gas-based vertical furnace to produce DRI (Direct reduced iron), which can reduce the pollution of the coking industry to the ecological environment.

[0030] In this embodiment, the purification treatment device for coke oven gas includes a pre-purification device 10 , a compression device 20 and a hydrodesulfurization device 30 ; wherein the hydrodesulfurization device 30 is placed downstream of the pre-purification device 10 and the compression device 20 .

[0031] Among them, the pre-purification device 10 includes a first pretreatment tower and an adsorption tower group 12. The adsorption tower group 12 is placed downstream of the first pretreatment tower. The first pretreatment tower is used to remove H2S in the coke oven gas, and the adsorption tower group 12 is used to remove tar, dust, naphthalene and part of benzene in the coke oven gas.

[0032] The adsorption tower group 12 uses adsorbents to adsorb tar, dust, naphthalene and part of benzene. The adsorbent needs to be regenerated after working for a period of time to restore its adsorption capacity. Placing the first pretreatment tower for removing H2S upstream of the adsorption tower group 12 can prevent the H2S adsorbed by the adsorbent of the adsorption tower group 12 from being oxidized into elemental sulfur during the regeneration process and clogging the microporous structure of the adsorbent, thereby affecting the adsorption efficiency of the adsorbent.

[0033] The compression device 20 is used to pressurize the coke oven gas to meet the pressure requirement of the vertical furnace for the coke oven gas.

[0034] The hydrodesulfurization device 30 includes a hydrogenation reaction component and a desulfurization device. The desulfurization device is placed downstream of the hydrogenation reaction component. The hydrogenation reaction component is used to convert organic sulfur in the coke oven gas into inorganic sulfur. The desulfurization device is used to remove inorganic sulfur in the coke oven gas after being treated by the hydrogenation reaction component.

[0035] After the coke oven gas of the coking plant is treated with the above scheme, impurities such as sulfur, tar, naphthalene, dust and benzene in the coke oven gas can be effectively removed. The content of impurities such as sulfur, tar, naphthalene, dust and benzene in the coke oven gas after purification can meet the DRI requirements for the impurity content of coke oven gas, and can be directly added to the gas-based vertical furnace cone section for further reforming and used as supplementary gas for reducing gas to produce gas-based vertical furnace DRI products.

[0036] In one feasible solution, Figure 1 As shown, the pre-purification device 10 is placed upstream of the compression device 20, so that the coke oven gas from the coking plant is first processed by the pre-purification device 10, then enters the compression device 20 for pressurization, and finally enters the hydrodesulfurization device 30 for treatment. Placing the compression device 20 downstream of the pre-purification device 10 can purify the coke oven gas before pressurization, which can reduce the adverse effects of impurities in the coke oven gas on the compression device 20, which is conducive to extending the maintenance period of the compression device 20 and facilitating the stable operation of the compression device 20.

[0037] Of course, in another feasible solution, the compression device 20 may also be placed upstream of the pre-purification device 10, that is, the coke oven gas is first pressurized and then purified.

[0038] It should be pointed out that no matter how the pre-purification device 10 and the compression device 20 are positioned, the coke oven gas must be pressurized before entering the hydrodesulfurization device for treatment, that is, the coke oven gas can only enter the hydrodesulfurization device for treatment after being pressurized to ensure the hydrogenation effect and thus the desulfurization effect.

[0039] Please refer to Figure 2 , Figure 2 It is a process flow chart of the pre-purification device of the purification treatment device in a specific embodiment.

[0040] In a specific implementation, the pre-purification device 10 may adopt a TSA (Temperature Swing Adsorption) device.

[0041] The first pretreatment tower in the pre-purification device 10 may be a desulfurization tower. In the illustrated example, the first pretreatment tower includes a desulfurization tower 11 .

[0042] In other embodiments, the first pretreatment tower may be provided with more than two desulfurization towers 11, and the number of desulfurization towers 11 provided in the first pretreatment tower is related to the H2S content in the coke oven gas from the coking plant and the replacement cycle of the desulfurizer. Generally speaking, the higher the H2S content in the coke oven gas from the coking plant, the longer the replacement cycle of the desulfurizer, and the more desulfurization towers 11 are required.

[0043] In the specific implementation, the first pretreatment tower is set so that the H2S content in the coke oven gas from the coking plant is not higher than 20 mg / Nm 3 .

[0044] In a specific implementation, the adsorption tower group 12 of the pre-purification device 10 includes at least four adsorption towers, and the operation process of each adsorption tower includes an adsorption process and a regeneration process. After a period of adsorption, the adsorbent in the adsorption tower will not have adsorption capacity, and at this time, it needs to be regenerated to restore the adsorption capacity of the adsorbent. Therefore, the operation process of the adsorption tower can be divided into an adsorption process and a regeneration process.

[0045] In the adsorption process (A) stage, the coke oven gas treated by the desulfurization tower 11 enters the adsorption tower for adsorption. When the front of the mass transfer zone of the adsorbed impurities (also called the adsorption front) reaches the reserved section at the outlet of the adsorbent bed, the adsorption stops and enters the regeneration process.

[0046] The regeneration gas used in the regeneration process may be a portion of the coke oven gas purified by the pre-purification device 10. For example, the regeneration gas may account for 10% of the total purified gas. Of course, in actual applications, additional regeneration gas may also be introduced.

[0047] The regeneration process may include:

[0048] 1) Pressure relief process (D)

[0049] After the adsorption is completed, the pressure in the adsorption tower is released in the opposite direction of the adsorption to match the force of the regeneration gas.

[0050] 2) Heating process (H)

[0051] After the pressure relief is completed, the regeneration gas from the adsorption tower in the cooling process is heated by the regeneration gas heater 13, and then the adsorbent bed is purged in the opposite direction of the adsorption direction, so that the adsorbed impurities can be desorbed under high temperature conditions. The desorbed impurities flow out from the bottom of the adsorption tower along with the regeneration gas to the regeneration gas cooler 14, and can be sent to the coke oven after cooling and separation in the regeneration gas gas-liquid separator 15.

[0052] In a specific implementation, the regeneration gas may be heated to about 200° C. by the regeneration gas heater 13 .

[0053] In a specific implementation, when the gas temperature at the bottom outlet of the adsorption tower is higher than the first set temperature (eg, 170° C.), the heating process may be terminated.

[0054] 3) Cooling process (C)

[0055] After heating, the adsorbent bed is purged with regeneration gas at room temperature in the opposite direction of adsorption, so that the adsorbent is cooled to restore the adsorption capacity.

[0056] The regeneration gas after cooling treatment can be used as the regeneration gas of another adsorption tower in the heating process, or it can be directly sent to the coke oven after passing through the cooler 14 and the regeneration gas-liquid separator 15.

[0057] In a specific implementation, when the gas temperature at the top outlet of the adsorption tower is lower than the second set temperature (eg 40° C.), the cooling process may be terminated.

[0058] 4) Replacement process (R)

[0059] After cooling, the regeneration gas in the adsorption tower is replaced with the regeneration gas in the opposite direction of adsorption. The replacement can ensure the stability of the gas outlet from the adsorption tower after entering the adsorption process.

[0060] In specific implementation, among the at least four adsorption towers mentioned above, at least two adsorption towers are in the adsorption process, and at least two adsorption towers are in the regeneration process. In this way, it can be ensured that the adsorption tower group 12 can realize the continuous removal of tar, dust, naphthalene and benzene from the coke oven gas.

[0061] Each adsorption tower of the adsorption tower group 12 can control the operation of the adsorption tower by controlling the switch state of the valve of each passage through a time program. Figure 2 In the example shown, the adsorption tower group 12 of the pre-purification device 10 is provided with four adsorption towers, namely, a first adsorption tower 12-1, a second adsorption tower 12-2, a third adsorption tower 12-3 and a fourth adsorption tower 12-4. Figure 2 It can be seen that each adsorption tower is provided with a gas flow path corresponding to the above-mentioned processes, and relevant valves are provided on each flow path. The operation process of the adsorption tower can be adjusted by switching the relevant valves on these flow paths.

[0062] Below Figure 2 The figure shows an example to illustrate a sequential operation of four adsorption towers.

[0063] Table 1- Sequential operation table of the four adsorption towers in the adsorption tower group

[0064]

[0065] Referring to Table 1 above, "A" in Table 1 represents an adsorption process, "D" represents a pressure relief process, "H" represents a heating process, "C" represents a cooling process, and "R" represents a displacement process.

[0066] It can be seen from Table 1 that the first adsorption tower 12-1 is in the adsorption process at the 1st to 6th time sequence, in the pressure release process at the 7th time sequence, in the heating process at the 8th time sequence, in the cooling process at the 9th to 11th time sequence, and in the replacement process at the 12th time sequence; the second adsorption tower 12-2 is in the cooling process at the 12th time sequence and the 1st to 2nd time sequence, in the replacement process at the 3rd time sequence, in the adsorption process at the 4th to 9th time sequence, in the pressure release process at the 10th time sequence, and in the heating process at the 11th time sequence; the third adsorption tower 12-3 is in the pressure release process at the 1st time sequence, in the heating process at the 2nd time sequence, in the cooling process at the 3rd to 5th time sequence, in the replacement process at the 6th time sequence, and in the adsorption process at the 7th to 12th time sequence; the fourth adsorption tower 12-4 is in the adsorption process at the 10th to 12th and 1st to 3th time sequences, in the pressure release process at the 4th time sequence, in the heating process at the 5th time sequence, in the cooling process at the 6th to 8th time sequence, and in the replacement process at the 9th time sequence.

[0067] By comparison, it can be seen that in each time sequence, two adsorption towers are in the adsorption process and two adsorption towers are in the regeneration process. In this way, it can be ensured that the adsorption tower group 12 can perform continuous adsorption operation on the coke oven gas to achieve continuous removal of tar, naphthalene, dust and benzene impurities.

[0068] In a specific implementation, each adsorption tower of the adsorption tower group 12 uses the same adsorbent, and the adsorbent can be an activated carbon adsorbent.

[0069] In a specific implementation, the arrangement of the adsorption tower group 12 ensures that the naphthalene content in the coke oven gas after being treated by the adsorption tower group 12 is not higher than 2 mg / Nm 3 , tar content is not higher than 2mg / Nm 3 , dust content is not higher than 2mg / Nm 3 , benzene content is not higher than 2000mg / Nm 3 .

[0070] by Figure 1 In the example shown, the coke oven gas is processed by the pre-purification device 10 and then pressurized by the compression device 20 .

[0071] Generally speaking, coke oven gas is slightly positive pressure at room temperature, while the operating pressure of a gas-based vertical furnace is 8-10 bar.A. Therefore, a compression device 20 is provided to pressurize the coke oven gas so that the coke oven gas can meet the pressure required by the vertical furnace.

[0072] The compression device 20 is implemented by a compressor, and the coke oven gas is pressurized by the compressor. In a feasible solution, the compression device 20 uses a water-sprayed wet screw compressor. The water-sprayed wet screw compressor can reduce the temperature rise of the gas during the compression process and protect the compressor.

[0073] Of course, in other feasible solutions, the compression device 20 may also be a centrifugal compressor or a reciprocating compressor.

[0074] In specific implementation, the outlet pressure of the compression device 20 is set not lower than 1.1 MPa.G.

[0075] Please refer to Figure 3 , Figure 3 It is a process flow chart of the hydrodesulfurization device in a specific embodiment.

[0076] In this embodiment, the hydrogenation reaction component of the hydrodesulfurization device 30 includes a pre-hydrogenation reaction component 31 and a primary hydrogenation reactor 32 arranged in series, the pre-hydrogenation reaction component 31 is placed upstream of the primary hydrogenation reactor 32, and the desulfurization equipment of the hydrodesulfurization device 30 is placed downstream of the primary hydrogenation reactor 32; the hydrodesulfurization device 30 also includes a steam generator 36 and a cooler 37 arranged downstream of the primary hydrogenation reactor 32.

[0077] The coke oven gas pressurized by the compression device 20 enters the pre-hydrogenation reaction component 31 and the primary hydrogenation reactor 32 in sequence, and undergoes pre-hydrogenation and primary hydrogenation treatments in the pre-hydrogenation reaction component 31 and the primary hydrogenation reactor 32, respectively. After the pre-hydrogenation and primary hydrogenation, the organic sulfur in the coke oven gas can be converted into inorganic sulfur for subsequent desulfurization treatment by a desulfurization device.

[0078] The reaction equations during pre-hydrogenation and primary hydrotreatment are as follows:

[0079] COS+H2→CO+H2S;

[0080] CS2+4H2→CH4+2H2S;

[0081] C4H4S+4H2→C4H 10 +H2S.

[0082] After the hydrogenation reaction, the organic sulfur in the coke oven gas is converted into inorganic sulfur H2S. At this time, desulfurization equipment can be used to remove the inorganic sulfur H2S so that the total sulfur content in the treated coke oven gas meets the requirements of the gas-based vertical furnace.

[0083] Under the action of hydrogenation catalyst, coke oven gas will also undergo the following reactions:

[0084] 2H2+O2→2H2O; CO+3H2→CH4+H2O.

[0085] That is, the hydrogenation process is accompanied by a methanation side reaction, which is an exothermic reaction. To prevent the system from overheating, the steam generator 36 disposed downstream of the hydrodesulfurization device 30 can use boiler feed water to generate steam to remove the reaction heat of the system.

[0086] The cooler 37 can be provided to cool the coke oven gas after the hydrogenation treatment.

[0087] Figure 3 In the example shown, the desulfurization equipment of the hydrodesulfurization unit 30 is a wet desulfurization equipment, which is placed downstream of the cooler 37 .

[0088] In a specific implementation, the hydrodesulfurization device 30 is further provided with a second pretreatment tower 33 upstream of the pre-hydrogenation reaction assembly 31 , and the second pretreatment tower 33 is used to remove impurities such as oil and dust in the coke oven gas.

[0089] In a specific implementation, the hydrodesulfurization device 30 further includes a heater 35 and a heat exchanger 34, wherein the heater 35 is disposed upstream of the hydrogenation reaction assembly, that is, the heater 35 is disposed upstream of the pre-hydrogenation reaction assembly 31. The heat exchanger 34 has a first passage and a second passage, wherein the first passage of the heat exchanger 34 is serially connected upstream of the pre-hydrogenation reaction assembly 31, and the second passage is serially connected downstream of the primary hydrogenation reactor, and the second passage is arranged in parallel with the steam generator 36.

[0090] In this way, in the initial operation stage after the purification treatment device is started, the coke oven gas entering the hydrogenation reaction component can be heated by the heater 35 to reach the activation temperature of the hydrogenation reaction, so as to facilitate the hydrogenation reaction; after the purification treatment device is started for a period of time, due to the increase in the heat released by the hydrogenation reaction, the coke oven gas that has not yet entered the hydrogenation reaction component can be used for heat exchange and temperature increase by using the coke oven gas treated by the hydrogenation reaction component to ensure the temperature of the hydrogenation reaction. At this time, the heater 35 can be turned off.

[0091] By setting the heat exchanger 34, the heat generated by the hydrogenation reaction can be reasonably utilized and recovered, which can save the heater 35 from working for a long time and is conducive to saving energy.

[0092] In practical applications, the heater 35 may be an electric heater.

[0093] In a specific implementation, the hydrodesulfurization device 30 is further provided with a separator 38 downstream of the cooler 37 to separate the coke oven gas into gas and liquid and then send the gas to the wet desulfurization equipment for desulfurization treatment.

[0094] In the illustrated example, the pre-hydrogenation reaction assembly 31 of the hydrogenation reaction assembly includes two pre-hydrogenation reactors arranged in parallel, that is, the coke oven gas is divided into two paths and enters the two pre-hydrogenation reactors respectively for pre-hydrogenation treatment, and then flows into the primary hydrogenation reactor 32 together for primary hydrogenation treatment.

[0095] In other embodiments, the pre-hydrogenation reaction assembly 31 may be provided with three or more pre-hydrogenation reactors in parallel according to application requirements; and a secondary hydrogenation reactor may be connected in series after the primary hydrogenation reactor 32 according to application requirements. Generally speaking, after the pre-hydrogenation and primary hydrogenation treatment, the sulfur in the coke oven gas can be removed to meet the use requirements of the gas-based shaft furnace.

[0096] In a specific implementation, the total sulfur content of the coke oven gas after being treated by the hydrodesulfurization device 30 is not higher than 20 mg / Nm 3 .

[0097] Apart from Figure 3 In addition to the examples shown, in other embodiments, the desulfurization equipment in the hydrodesulfurization device 30 may also be a dry desulfurization equipment, or a combination of a dry desulfurization equipment and a wet desulfurization equipment.

[0098] Among them, the dry desulfurization equipment can be in the form of a desulfurization tower.

[0099] In a feasible solution, the dry desulfurization equipment can adopt a medium-temperature desulfurization tower. In this case, the medium-temperature desulfurization tower can be connected in series between the first-stage hydrogenation reactor 32 and the cooler 37, that is, the medium-temperature desulfurization tower is set upstream of the cooler 37; illustratively, the number of medium-temperature desulfurization towers can be set to more than two, which is related to the specific desulfurization demand.

[0100] In another feasible solution, the dry desulfurization equipment can also use a normal temperature desulfurization tower, which can be connected in series downstream of the cooler 37; illustratively, the number of normal temperature desulfurization towers can be more than two, which is related to the desulfurization demand.

[0101] Generally speaking, medium-temperature desulfurizers have high sulfur capacity and a long replacement cycle, while room-temperature desulfurizers have low sulfur capacity and a short replacement cycle. When implementing, you can choose according to actual application needs.

[0102] In the combination of dry desulfurization equipment and wet desulfurization equipment, the dry desulfurization equipment can be connected in series downstream of the wet desulfurization equipment.

[0103] The present application also provides a method for purifying coke oven gas, the method comprising the following steps:

[0104] Pre-purification treatment: The coke oven gas from the coke oven plant is first desulfurized to ensure that the H2S content in the coke oven gas is no higher than 20 mg / Nm 3 , and then remove tar, dust, naphthalene and benzene to make the naphthalene content in the coke oven gas no higher than 2 mg / Nm 3 , tar content is not higher than 2mg / Nm 3 , dust content is not higher than 2mg / Nm 3, benzene content is not higher than 2000mg / Nm 3 ;

[0105] Pressurization treatment: compress the coke oven gas that has been pre-purified, and specifically make the pressure of the coke oven gas not less than 1.1MPa.G;

[0106] Hydrodesulfurization treatment: The pressurized coke oven gas is first subjected to hydrogenation treatment and then desulfurization treatment to ensure that the total sulfur content in the coke oven gas is not less than 20 mg / Nm 3 .

[0107] The above-mentioned pretreatment process can be implemented by using the aforementioned pre-purification device 10 , the pressurization treatment process can be implemented by using the aforementioned compression device 20 , and the hydrodesulfurization treatment process can be implemented by using the aforementioned hydrodesulfurization device 30 .

[0108] Among them, the desulfurization treatment in the pre-purification treatment can be considered as a rough desulfurization treatment, and the desulfurization treatment in the subsequent hydrodesulfurization treatment can be considered as a fine desulfurization treatment. In the pre-purification treatment, the inorganic sulfur in the coke oven gas is first removed to avoid affecting the removal of tar, dust, naphthalene and benzene.

[0109] In another embodiment, the order of the pre-purification step and the pressurization step of the above purification method can be reversed, that is, the pressurization step can be performed first, followed by the pre-purification step, and finally the hydrodesulfurization step.

[0110] In a specific implementation, in the hydrodesulfurization process, the hydrogenated coke oven gas can be heat-recovered. Specifically, the heat recovery process can be to use the hydrogenated coke oven gas to heat boiler feed water, or to use the hydrogenated coke oven gas to heat the coke oven gas before hydrogenation.

[0111] In an application example, the comparison of the logistics composition of coke oven gas from a coke oven plant after pre-purification and hydrodesulfurization treatment can be seen in Table 2.

[0112] Table 2 - Changes in the logistics composition of coke oven gas in an application example

[0113]

[0114] After the coke oven gas from the coke oven plant is purified by the above purification device and method, the tar content in the coke oven gas is not higher than 2 mg / Nm 3 , dust content is not higher than 2mg / Nm 3 , naphthalene content is not higher than 2mg / Nm 3 , benzene content is not higher than 2000mg / Nm 3 , the total sulfur content is not higher than 20mg / Nm 3, coke oven gas that meets the needs of gas-based vertical furnaces can be obtained, and the purified coke oven gas can be used as supplementary gas for the reducing gas of the gas-based vertical furnace.

[0115] Normal temperature, medium temperature or medium pressure mentioned in this article are all relative concepts. In actual applications, the specific value range can be determined according to the application scenario and requirements, and is not limited here.

[0116] Specific examples are used herein to illustrate the principles and implementation methods of the present application, and the description of the above embodiments is only used to help understand the method and core ideas of the present application. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A purification device for coke oven gas, characterized in that: It comprises a pre-purification device, a compression device and a hydrodesulfurization device, wherein the hydrodesulfurization device is placed downstream of the pre-purification device and the compression device; The pre-purification device comprises a first pre-treatment tower and an adsorption tower group, wherein the adsorption tower group is placed downstream of the first pre-treatment tower, the first pre-treatment tower is used to remove H2S in the coke oven gas, and the adsorption tower group is used to remove tar, dust, naphthalene and part of benzene in the coke oven gas; The compression device is used to pressurize the coke oven gas; The hydrodesulfurization device comprises a hydrogenation reaction component and a desulfurization device, wherein the desulfurization device is placed downstream of the hydrogenation reaction component, the hydrogenation reaction component is used to convert organic sulfur in coke oven gas into inorganic sulfur, and the desulfurization device is used to remove inorganic sulfur in the coke oven gas treated by the hydrogenation reaction component.

2. The purification device for coke oven gas according to claim 1, characterized in that: The compression device is placed between the pre-purification device and the hydrodesulfurization device.

3. The purification device for coke oven gas according to claim 2, characterized in that: The compression device is a water-sprayed wet screw compressor.

4. The coke oven gas purification device according to claim 2, characterized in that: The outlet pressure of the compression device is not less than 1.1 MPa.G.

5. The purification device for coke oven gas according to claim 1, characterized in that: The first pretreatment tower includes at least one desulfurization tower, and the H2S content in the coke oven gas treated by the first pretreatment tower is not higher than 20 mg / Nm 3 .

6. The purification device for coke oven gas according to claim 5, characterized in that: The adsorption tower group includes at least four adsorption towers, among which at least two are in the adsorption process and at least two are in the regeneration process; the naphthalene content in the coke oven gas treated by the adsorption tower group is not higher than 2 mg / Nm 3 , tar content is not higher than 2mg / Nm 3 , dust content is not higher than 2mg / Nm 3 , benzene content is not higher than 2000mg / Nm 3 .

7. The coke oven gas purification device according to any one of claims 1 to 6, characterized in that: The hydrogenation reaction assembly comprises a pre-hydrogenation reaction assembly and a primary hydrogenation reactor arranged in series; the pre-hydrogenation reaction assembly is placed upstream of the primary hydrogenation reactor, and the desulfurization equipment is placed downstream of the primary hydrogenation reactor; the hydrodesulfurization device also comprises a steam generator and a cooler arranged downstream of the primary hydrogenation reactor, and the cooler is placed downstream of the steam generator; The desulfurization equipment includes a dry desulfurization equipment and / or a wet desulfurization equipment, wherein the dry desulfurization equipment includes a desulfurization tower placed upstream or downstream of the cooler, and the wet desulfurization equipment is placed downstream of the cooler; The total sulfur content of the coke oven gas treated by the hydrodesulfurization device is not higher than 20 mg / Nm 3 .

8. The coke oven gas purification device according to claim 7, characterized in that: The hydrodesulfurization device further comprises a heater and a heat exchanger, wherein the heater is disposed upstream of the pre-hydrogenation reaction assembly; The heat exchanger comprises a first passage and a second passage, wherein the first passage is connected in series to the upstream of the pre-hydrogenation reaction assembly, and the second passage is connected in series to the downstream of the primary hydrogenation reactor and is arranged in parallel with the steam generator.

9. The coke oven gas purification device according to claim 7, characterized in that: The pre-hydrogenation reaction assembly includes two or more pre-hydrogenation reactors arranged in parallel.

10. The coke oven gas purification device according to claim 7, characterized in that: The hydrodesulfurization device further comprises a second pretreatment tower disposed upstream of the hydrogenation reaction assembly, and the second pretreatment tower is used to remove oil and dust from the coke oven gas flowing through the tower.

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