Purification plant of coke oven gas

Abstract

The application discloses a purification device for coke oven gas, which comprises a first gas-liquid separator, a dehydration tower, a mercury removal tower, a purification tower and a dust filter. The inlet end of the first gas-liquid separator is connected with a gas source of raw material gas. The bottom of the dehydration tower is connected with the outlet end of the first gas-liquid separator through a first pipeline. The mercury removal tower is arranged downstream of the dehydration tower. The inlet end of the mercury removal tower is connected with the top of the dehydration tower through a fourth pipeline. The purification tower is arranged downstream of the mercury removal tower. The bottom of the purification tower is connected with the outlet end of the mercury removal tower. The dust filter is arranged downstream of the purification tower. The inlet end of the dust filter is connected with the top of the purification tower through a fifth pipeline. The outlet end of the dust filter is used for discharging purified clean gas. The purification device can remove water, mercury, carbon dioxide and heavy hydrocarbon impurities in the coke oven gas in sequence, can adapt to the fluctuation of impurities in the coke oven gas after methanation, and can improve the stability of the gas composition entering a liquefaction cold box.

Description

Technical Field

[0001] This application relates to the field of coke oven gas purification technology, and particularly to a coke oven gas purification device. Background Technology

[0002] Coke oven gas is a byproduct of the coking industry, mainly composed of hydrogen, methane, CO, CO2, and trace amounts of tar, naphthalene, benzene, etc. Currently, the industrial uses of coke oven gas include industrial and domestic fuel (heating and power generation), chemical raw material (synthetic ammonia and methanol production), iron smelting, and hydrogen production.

[0003] Coke oven gas is an ideal feedstock for LNG (Liquefied Natural Gas) conversion. Currently, the conventional process for producing LNG from coke oven gas involves passing the gas through a gas holder, compression desulfurization, oil and naphthalene removal, methanation, and cryogenic separation to obtain LNG. Methanation and cryogenic separation technologies convert coke oven gas into LNG. The methane-rich gas after methanation is then dehydrated in a dehydration tower before entering the liquefaction unit. However, in actual operation, factors such as changes in coke oven gas composition and fluctuations in upstream processes result in residual impurities such as CO2, heavy hydrocarbons, and mercury in the gas after methanation. CO2 and heavy hydrocarbons can cause freezing and blockage of the liquefaction cold box, while mercury can corrode the aluminum liquefaction cold box, causing perforations, gas leaks, and ultimately, unit shutdown. Utility Model Content

[0004] In view of the shortcomings of the prior art, the purpose of this application is to provide a coke oven gas purification device, which aims to improve the flexibility of the purification device in processing gas from the upstream methanation unit.

[0005] Another objective of this application is to ensure that the purified coke oven gas meets the feed gas requirements of the liquefied gas cooling box.

[0006] To achieve the above objectives, this application adopts the following technical solution:

[0007] This application discloses a coke oven gas purification device, which includes a first gas-liquid separator, a dehydration tower, a mercury removal tower, a purification tower, and a dust filter. The inlet of the first gas-liquid separator is connected to the gas source of the raw material gas. The bottom of the dehydration tower is connected to the outlet of the first gas-liquid separator through a first pipe. The mercury removal tower is located downstream of the dehydration tower, and its inlet is connected to the top of the dehydration tower through a fourth pipe. The purification tower is located downstream of the mercury removal tower, and its bottom is connected to the outlet of the mercury removal tower. The dust filter is located downstream of the purification tower, and its inlet is connected to the top of the purification tower through a fifth pipe. The outlet of the dust filter is used to discharge the purified gas.

[0008] In some embodiments of this application, at least two dehydration towers are provided, and multiple dehydration towers are arranged in parallel; and / or,

[0009] The purification tower is provided with at least two towers, and multiple purification towers are arranged in parallel.

[0010] In some embodiments of this application, the purification device includes a first heater, a second gas-liquid separator, and a first cooler; the inlet end of the first heater is connected to the fourth pipeline, the outlet end of the first heater is connected to the fourth pipeline, the inlet end of the second gas-liquid separator is connected to the first pipeline through a second pipeline, the outlet end of the second gas-liquid separator is connected to the first pipeline through a third pipeline, and the first cooler is disposed on the second pipeline for cooling the raw material gas discharged from the bottom of the dehydration tower.

[0011] In some embodiments of this application, the purification device includes a second heater, the inlet of which is connected to a regeneration gas source via a sixth pipe, and the outlet of which is connected to the top of the purification tower via a seventh pipe; the regeneration gas source is connected to the top of the purification tower via an eleventh pipe.

[0012] In some embodiments of this application, the purification apparatus further includes a second cooler, the inlet of which is connected to the bottom of the purification tower via an eighth pipe, and the inlet of which is connected to the eleventh pipe via a ninth pipe.

[0013] In some embodiments of this application, the top of the mercury removal tower is connected to the bottom of the purification tower via a twelfth pipe, and the twelfth pipe is connected to the inlet end of the second cooler via a thirteenth pipe;

[0014] The purification device also includes a pressure relief valve, which is located in the thirteenth pipeline and is used to relieve pressure on the purification tower after adsorption.

[0015] In some embodiments of this application, a tenth pipe is further connected between the purification tower and the dust filter. The two ends of the tenth pipe are respectively connected to the fifth pipe, and a first programmable valve is provided between the inlet end of the tenth pipe and the purification tower. The outlet end of the tenth pipe is connected between the purification tower and the first programmable valve.

[0016] The purification device also includes a pressurization valve, which is located in the tenth pipeline and is used to pressurize the regenerated purification tower.

[0017] In some embodiments of this application, a programmable valve is provided on the connecting pipe of the purification device.

[0018] In some embodiments of this application, the regeneration gas includes at least one of nitrogen and nitrogen-rich gas.

[0019] In some embodiments of this application, the purification apparatus further includes a carbon dioxide monitor located downstream of the purification tower for monitoring the carbon dioxide content in the purified raw gas; and / or,

[0020] The purification device also includes a moisture monitor, which is located at the outlet of the dehydration tower and is used to monitor the moisture content in the purified gas after dehydration.

[0021] Beneficial effects:

[0022] The coke oven gas purification device provided in this application, by setting up a first gas-liquid separator, a dehydration tower, a mercury removal tower, a purification tower and a dust filter connected in sequence, enables the removal of impurities such as moisture, mercury, carbon dioxide and heavy hydrocarbons in the coke oven gas feedstock gas, improves the applicability to the fluctuation of impurities in the coke oven gas after methanation, and makes the purified gas suitable for the conditions required to enter the downstream liquefaction cold box. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the connection structure of a coke oven gas purification device provided in one embodiment of this application.

[0024] Explanation of key component symbols:

[0025] 1. First gas-liquid separator; 2a / 2b / 2c. Dehydration tower; 3. Mercury removal tower; 4a / 4b. Purification tower; 5. Dust filter; 6. First heater; 7. Second gas-liquid separator; 8. First cooler; 9. Second heater; 10. Second cooler; 11. Programmable valve; 11a. First programmable valve; 12. Pressure relief valve; 13. Pressurization valve; 14. First pipeline; 15. Second pipeline; 16. Third pipeline; 17. Fourth pipeline; 18. Fifth pipeline; 19. Sixth pipeline; 20. Seventh pipeline; 21. Eighth pipeline; 22. Ninth pipeline; 23. Tenth pipeline; 24. Eleventh pipeline; 25. Twelfth pipeline; 26. Thirteenth pipeline. Detailed Implementation

[0026] This application provides a purification device for coke oven gas. To make the objectives, technical solutions, and effects of this application clearer and more explicit, the following detailed description is provided with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining this application and are not intended to limit this application.

[0027] In the description of this application, it should be understood that the terms "upper," "lower," "left," and "right," etc., indicating orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or a specific orientational structure and operation. Therefore, they should not be construed as limitations on this application. Furthermore, "first" and "second" are only for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "multiple" means two or more.

[0028] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0029] Please see Figure 1 This application provides a coke oven gas purification device. The raw gas for the purification device comes from the coke oven gas produced by the upstream methanation unit. The purified gas obtained after purification by the purification device can enter the downstream liquefaction cold box.

[0030] Specifically, the purification device includes a first gas-liquid separator 1, dehydration towers 2a / 2b / 2c, mercury removal tower 3, purification towers 4a / 4b, and a dust filter 5, connected sequentially along the flow direction of the raw gas. The inlet of the first gas-liquid separator 1 is connected to the source of the raw gas. The bottom of the dehydration towers 2a / 2b / 2c is connected to the outlet of the first gas-liquid separator 1 via a first pipe 14. The mercury removal tower 3 is located downstream of the dehydration towers 2a / 2b / 2c, and its inlet is connected to the top of the dehydration towers 2a / 2b / 2c via a fourth pipe 17. The purification towers 4a / 4b are located downstream of the mercury removal tower 3, and their bottoms are connected to the outlet of the mercury removal tower 3. The dust filter 5 is located downstream of the purification towers 4a / 4b, and its inlet is connected to the top of the purification towers 4a / 4b via a fifth pipe 18. The outlet of the dust filter 5 is used to discharge the purified gas.

[0031] During actual operation of the methanation unit, factors such as changes in coke oven gas composition and fluctuations in upstream processes can lead to residual impurities such as carbon dioxide, heavy hydrocarbons, and mercury in the gas after methanation. These impurities can cause freezing and blockage of the liquefaction cold box, and mercury can corrode the aluminum liquefaction cold box, resulting in gas leaks and affecting the normal operation of the unit.

[0032] In the above process, the raw gas sequentially passes through the first gas-liquid separator 1, dehydration towers 2a / 2b / 2c, mercury removal tower 3, purification towers 4a / 4b, and dust filter 5. This effectively removes impurities such as moisture, mercury, carbon dioxide, and heavy hydrocarbons from the raw gas, resulting in deep purification. The purified gas then enters the downstream liquefaction cold box, preventing freezing and blockage, and avoiding corrosion, thus ensuring the effective operation of the equipment.

[0033] Furthermore, at least two dehydration towers 2a / 2b / 2c are provided, and multiple dehydration towers 2a / 2b / 2c are arranged in parallel. Each dehydration tower 2a / 2b / 2c can be connected to the first gas-liquid separator 1 through a first pipe 14. The raw material gas discharged from the first gas-liquid separator 1 is divided into at least two paths and simultaneously enters two different dehydration towers 2a / 2b / 2c, so that at least two dehydration towers 2a / 2b / 2c can be in different operating states.

[0034] The operating states of dehydration towers 2a / 2b / 2c can include adsorption state, heating state, and cold blowing state.

[0035] In some embodiments, dehydration towers 2a / 2b / 2c may include three towers, each operating in one of the three aforementioned working states. The raw material gas discharged from the first gas-liquid separator 1 is split into two paths. One path enters the dehydration tower 2a / 2b / 2c in the adsorption state for moisture separation. The other path enters the dehydration tower 2a / 2b / 2c after heating has finished to perform cold blowing treatment. During this process, the raw material gas enters from the bottom of the dehydration tower 2a / 2b / 2c and exits from the top. The raw material gas after moisture separation enters the downstream mercury removal tower 3 through the fourth pipe 17. The cold-blown raw material gas, after heating, is introduced from the top of the dehydration tower 2a / 2b / 2c in the heating state to regenerate it.

[0036] The purification device may also include a first heater 6. The inlet end of the first heater 6 is connected to the fourth pipe 17, and the outlet end of the first heater 6 is connected to the fourth pipe 17. The raw material gas after being cold-blown through the dehydration towers 2a / 2b / 2c enters the first heater 6 for heating. The heated raw material gas can then be passed through the fourth pipe 17 into the heated dehydration towers 2a / 2b / 2c to remove water from the adsorbent and regenerate the dehydration towers 2a / 2b / 2c through heating.

[0037] It is understandable that a fourth pipe 17 is connected to each of the different dehydration towers 2a / 2b / 2c, and the first heater 6 is connected to the fourth pipe 17 of each of the different dehydration towers 2a / 2b / 2c. In this way, the raw material gas in the dehydration towers 2a / 2b / 2c after cold blowing can enter another dehydration tower 2a / 2b / 2c that is in a heated state after being heated.

[0038] In some embodiments, the purification apparatus includes a second gas-liquid separator 7. The inlet of the second gas-liquid separator 7 is connected to the first pipe 14 via a second pipe 15, and the outlet of the second gas-liquid separator 7 is connected to the first pipe 14 via a third pipe 16. The raw material gas after being regenerated by the dehydration towers 2a / 2b / 2c is discharged from the bottom of the dehydration towers 2a / 2b / 2c, enters the second gas-liquid separator 7 through the second pipe 15 to separate water, and then returns to the first pipe 14 to enter the dehydration towers 2a / 2b / 2c in the adsorption state for dehydration treatment.

[0039] In some embodiments, the purification apparatus further includes a first cooler 8. The first cooler 8 is located in the second pipeline 15, between the dehydration towers 2a / 2b / 2c and the second gas-liquid separator 7, and is used to cool the raw material gas discharged after desorption from the dehydration towers 2a / 2b / 2c. The raw material gas after desorption treatment by the dehydration towers 2a / 2b / 2c has a high temperature; directly entering the second gas-liquid separator 7 would reduce the gas-liquid separation effect. The first cooler 8 can lower the temperature of the desorbed raw material gas, thereby improving the gas-liquid separation effect of the downstream second gas-liquid separator 7.

[0040] In some embodiments, at least two purification towers 4a / 4b are provided. Multiple purification towers 4a / 4b are arranged in parallel. The bottom of each purification tower 4a / 4b is connected to the top of the mercury removal tower 3 via a twelfth pipe 25, and the top of each purification tower 4a / 4b is connected to the dust filter 5 via a fifth pipe 18.

[0041] The purification towers 4a / 4b can operate in two states: adsorption and regeneration. The purification towers 4a / 4b alternate between these states sequentially. At least two of the multiple purification towers 4a / 4b can be in different operating states simultaneously, ensuring continuous operation of the purification unit and improving its operational sustainability and efficiency.

[0042] In some embodiments, two purification towers 4a / 4b are provided, one in an adsorption state and the other in a regeneration state. Coke oven gas discharged from the mercury removal tower 3 enters the purification tower 4a / 4b in the adsorption state, where impurities such as carbon dioxide and heavy hydrocarbons are removed. The gas then enters the dust filter 5 through the fifth pipe 18. After depressurization, the purification tower 4a / 4b in the adsorption state enters the regeneration state. The top of the purification tower 4a / 4b is connected to a regeneration gas source. Heated regeneration gas is introduced into the purification tower 4a / 4b in the regeneration state from the top, blowing the tower from top to bottom to remove carbon dioxide and heavy hydrocarbons from the adsorbent. The gas then exits from the bottom of the purification tower 4a / 4b. After the hot blowing, cold regeneration gas is introduced into the purification tower 4a / 4b from the top to regenerate it. After being cooled and blown, purification towers 4a / 4b are pressurized and then enter the adsorption state.

[0043] In some embodiments, the purification apparatus includes a second heater 9. The inlet of the second heater 9 is connected to a regeneration gas source via a sixth pipe 19, and the outlet of the second heater 9 is connected to the top of the purification tower 4a / 4b via a seventh pipe 20.

[0044] The regeneration gas can include at least one of nitrogen and nitrogen-enriched gas. The regeneration gas source can be nitrogen from the nitrogen generation unit or nitrogen-enriched gas from the liquefaction unit. Using nitrogen as the regeneration gas avoids secondary pollution of the wet-process amine solution.

[0045] Nitrogen or nitrogen-rich gas from the regenerated gas source enters the second heater 9 through the sixth pipe 19 for heating, and then enters the purification tower 4a / 4b after adsorption through the seventh pipe 20 for hot blowing, desorption and removal of carbon dioxide and heavy hydrocarbons from the adsorbent.

[0046] The regeneration gas source is connected to the top of the purification towers 4a / 4b via the eleventh pipe 24. After hot blowing, cold regeneration gas is introduced into the purification towers 4a / 4b through the eleventh pipe 24 to perform cold blowing on the purification towers 4a / 4b, thereby regenerating the purification towers 4a / 4b after cold blowing.

[0047] In some embodiments, the purification apparatus includes a second cooler 10. The inlet of the second cooler 10 is connected to the bottom of the purification tower 4a / 4b via an eighth pipe 21, and the inlet of the second cooler 10 is also connected to an eleventh pipe 24 via a ninth pipe 22. The regeneration gas discharged from the bottom of the purification tower 4a / 4b has a high temperature. The second cooler 10 can reduce the temperature of the regeneration gas, so that the regeneration gas discharged from the bottom of the purification tower 4a / 4b is cooled before being sent to the downstream unit.

[0048] In some embodiments, the top of the mercury removal tower 3 is connected to the bottom of the purification towers 4a / 4b via a twelfth pipe 25, and the twelfth pipe 25 is connected to the inlet of the second cooler 10 via a thirteenth pipe 26. The purification device includes a pressure relief valve 12. The pressure relief valve 12 is located on the thirteenth pipe 26 and can be used to relieve pressure on the purification towers 4a / 4b after the adsorption state has ended, so as to facilitate the introduction of hot regeneration gas into the purification towers 4a / 4b to desorb the adsorbent.

[0049] In some embodiments, a tenth pipe 23 is also connected between the purification towers 4a / 4b and the dust filter 5. Both ends of the tenth pipe 23 are connected to the fifth pipe 18, and a first programmable valve 11a is provided between the inlet end of the tenth pipe 23 and the purification towers 4a / 4b. The outlet end of the tenth pipe 23 is connected between the outlet end of the purification towers 4a / 4b and the first programmable valve 11a. The purification device includes a pressurization valve 13, which is located on the tenth pipe 23 and is used to pressurize the regenerated purification towers 4a / 4b.

[0050] Purification towers 4a / 4b are pressure swing adsorption devices, which can reduce the energy consumption of the equipment and improve the purification effect of coke oven gas.

[0051] In some embodiments, the purification apparatus may also include a carbon dioxide monitor (not shown in the figure). The carbon dioxide monitor is located downstream of purification towers 4a / 4b and is used to monitor the carbon dioxide content in the purified gas.

[0052] The purification unit includes a controller (not shown in the figure). The controller may include a monitoring and data acquisition system and a programmable logic controller. The carbon dioxide monitor is an online monitor, electrically connected to the controller. The carbon dioxide monitor can be installed at the outlet of the dust filter 5. Through this carbon dioxide monitor, the carbon dioxide content in the purified gas at the equipment outlet can be monitored in real time, thereby quickly adjusting factors such as the adsorption cycle of purification towers 4a / 4b and the amount of regeneration gas to ensure the stability of the purified gas composition.

[0053] In some embodiments, the purification apparatus also includes a moisture monitor (not shown in the figure). The moisture monitor is located at the outlet of the dehydration towers 2a / 2b / 2c and is used to monitor the moisture content in the dehydrated feed gas.

[0054] The moisture monitor is an online moisture monitor and is electrically connected to the controller. It can monitor the moisture content at the outlet of dehydration towers 2a / 2b / 2c in real time, and adjust the adsorption cycle and regeneration gas volume of dehydration towers 2a / 2b / 2c in a timely manner, thereby improving the operational flexibility of the purification unit.

[0055] Each connecting pipe of the purification unit is equipped with a programmable valve 11. Programmable valve 11, first programmable valve 11a, first gas-liquid separator 1, dehydration tower 2a / 2b / 2c, mercury removal tower 3, purification tower 4a / 4b, dust filter 5, first heater 6, second gas-liquid separator 7, second heater 9, first cooler 8, pressure relief valve 12, and pressure charging valve 13 are electrically connected to the controller. Each component of the purification unit can be adjusted in real time according to online data, improving the intelligence and flexibility of the purification unit, adapting to the fluctuations in impurities in the coke oven gas after methanation, and enhancing the operational stability and equipment safety of the downstream liquefaction cold box.

[0056] Another aspect of this application provides a method for purifying coke oven gas, which is performed using the aforementioned purification apparatus, and includes the following steps:

[0057] S100, the coke oven gas feedstock is separated from free water by the first gas-liquid separator 1. The coke oven gas feedstock comes from the methanation unit.

[0058] S200, the raw gas after separating free water enters the dehydration tower 2a / 2b / 2c to separate water.

[0059] The dehydration towers 2a / 2b / 2c operate in three states: adsorption, heating, and cold blowing. There are at least two dehydration towers 2a / 2b / 2c, and multiple dehydration towers 2a / 2b / 2c sequentially pass through different operating states. At least two dehydration towers 2a / 2b / 2c are simultaneously in different operating states, and at least one dehydration tower 2a / 2b / 2c is in the adsorption state. This allows the dehydration towers 2a / 2b / 2c to continuously dehydrate and separate coke oven gas, ensuring the continuity and stability of the purification unit's operation.

[0060] The raw material gas discharged from the first gas-liquid separator 1 is divided into at least two paths. One path enters the dehydration towers 2a / 2b / 2c in the adsorption state to separate the moisture in the raw material gas. The dried raw material gas after moisture separation enters the downstream mercury removal tower 3 through the fourth pipe 17.

[0061] The moisture content of the dehydrated raw gas is monitored online at the outlet of dehydration towers 2a / 2b / 2c by a moisture monitor. This allows for adjustment of the adsorption program of dehydration towers 2a / 2b / 2c based on real-time monitoring data, ensuring the purification effect of the purification device on the raw gas.

[0062] Another part of the raw gas after the separation of free water enters the dehydration towers 2a / 2b / 2c after the heating is completed for cold blowing. The raw gas after cold blowing enters the first heater 6 for heating and then passes from top to bottom through the dehydration towers 2a / 2b / 2c in the heated state to perform hot blowing on the dehydration towers 2a / 2b / 2c and desorb the moisture in the adsorbent.

[0063] The hot-blown raw material gas is discharged from the bottom of the dehydration towers 2a / 2b / 2c, cooled down by the first cooler 8, and then recirculated to the first pipeline 14 after the water is separated by the second gas-liquid separator 7, so as to enter the dehydration towers 2a / 2b / 2c in the adsorption state.

[0064] S300, the raw gas after water separation from dehydration towers 2a / 2b / 2c enters mercury removal tower 3 through the fourth pipe 17 to separate mercury from the raw gas.

[0065] S400, the raw material gas discharged from the mercury removal tower 3 enters the purification tower 4a / 4b for purification, and then passes through the dust filter 5 to obtain purified gas.

[0066] The purification towers 4a / 4b include an adsorption state and a regeneration state. There are at least two purification towers 4a / 4b. Multiple purification towers 4a / 4b enter the adsorption state and the regeneration state in sequence, and at least two purification towers 4a / 4b are in different states at the same time.

[0067] The raw gas discharged from the top of the mercury removal tower 3 is introduced into the purification towers 4a / 4b, which are in an adsorption state. It passes through the purification towers 4a / 4b from bottom to top and then exits from the top, entering the dust filter 5 to separate impurities, yielding purified gas. The purified gas can then be supplied to the downstream liquefied gas cooler.

[0068] The purified gas discharged from the outlet of dust filter 5 is monitored in real time by a carbon dioxide monitor to detect its impurity content. This allows for real-time adjustment of the adsorption program of purification towers 4a / 4b based on the composition of the purified gas, ensuring that the purified gas with the required composition is obtained.

[0069] After the adsorption state ends, the purification towers 4a / 4b are depressurized through the pressure relief valve 12, and then regeneration gas heated by the second heater 9 is introduced to regenerate the purification towers 4a / 4b. After passing through the purification towers 4a / 4b in the regeneration state, the regeneration gas enters the second cooler 10 for cooling before being discharged to the downstream unit or to the outside.

[0070] Cold regeneration gas is introduced into the purification towers 4a / 4b after hot blowing for cold blowing. The adsorbent in the purification towers 4a / 4b is regenerated by cold blowing. The regeneration gas after cold blowing enters the second cooler 10 for cooling.

[0071] After the cold blowing, the purification towers 4a / 4b are pressurized. After the pressurization is completed, the purification towers 4a / 4b enter the adsorption state, so that the raw material gas discharged from the top of the mercury removal tower 3 can continue to be purified.

[0072] Each step of the above purification method can be uniformly adjusted by the controller, which is simple to operate and highly flexible. The adsorption cycle of each adsorption component and the amount of regeneration gas can be adjusted in real time according to online monitoring data to ensure that the purified gas meets the operating requirements of the downstream liquefied gas cooler.

[0073] To better illustrate the solution of this application, specific examples are provided below to further explain this application.

[0074] Example 1

[0075] The flow rate from the aforementioned methanation unit is 46,000 Nm. 3 Coke oven gas at a pressure of 1.9 MPa and a temperature of 40°C (the composition of coke oven gas is shown in Table 1) is sent to the first gas-liquid separator to separate free water.

[0076] The coke oven gas discharged from the first gas-liquid separator is divided into two streams. One stream is sent to the dehydration tower in the adsorption state to remove water from the coke oven gas to ≤1ppm. The other stream, as dehydration regeneration gas, first passes through the dehydration tower after heating for cold blowing, and then enters the first heater to be heated to 220°C. The high-temperature regeneration gas is heated and regenerated in the dehydration tower in the heating state, desorbing and removing water from the adsorbent. After being cooled by the first cooler to about 40°C, the regeneration gas passes through the second gas-liquid separator to separate free water, and then returns to the first pipeline to merge with the first stream of raw gas and enter the dehydration tower in the adsorption state.

[0077] The dried and purified gas exiting the dehydration tower in an adsorption state enters the mercury removal tower to remove mercury from the coke oven gas to ≤0.01μg / m³. 3 .

[0078] After mercury removal, the coke oven gas enters a purification tower in an adsorption state, where impurities such as carbon dioxide and heavy hydrocarbons are removed to a concentration of ≤20 ppm for carbon dioxide and ≤10 ppm for heavy hydrocarbons. Pressure swing adsorption (PSA) is used for coke oven gas purification. The purified regeneration gas comes from the nitrogen mains or nitrogen-rich gas from the liquefaction unit. The purification tower, having just finished its adsorption state, is first depressurized via a pressure relief valve. The regeneration gas is then heated to 220°C by a second heater. This high-temperature regeneration gas enters the purification tower in its regeneration state, where it is heated and regenerated, removing carbon dioxide and heavy hydrocarbons from the adsorbent. The regeneration gas, after being desorbed, is cooled to approximately 40°C by a second cooler before being sent to the downstream unit. After hot blowing, the cold regeneration gas enters the purification tower, which has just finished its hot blowing state, for cold blowing. The cold-blown gas is then cooled by a second cooler before being sent to the downstream unit.

[0079] After the cold blowing is completed, the purified gas pressurizes the purification tower, which has just finished the regeneration process, through the pressurization valve. After pressurization, the purification tower enters the adsorption state. The coke oven gas exiting the purification tower passes through a dust filter to remove dust and other impurities before entering the downstream liquefaction cold box unit.

[0080] Table 1 Composition of Coke Oven Gas (Part 1)

[0081] Components <![CDATA[H2]]> <![CDATA[CH4]]> <![CDATA[H2O]]> <![CDATA[N2]]> <![CDATA[CO2]]> <![CDATA[C6 + ]]> Hg Composition mol% 39.98 52.145 0.385 7.49 100ppm 50ppm <![CDATA[1μg / m 3 ]]>

[0082] Example 2

[0083] The flow rate from the aforementioned methanation unit is 39,100 Nm. 3 Coke oven gas at a pressure of 2.2 MPa and a temperature of 40°C (the composition of coke oven gas is shown in Table 2) is sent to the first gas-liquid separator to separate free water.

[0084] The coke oven gas discharged from the first gas-liquid separator is divided into two streams. One stream is sent to the dehydration tower in the adsorption state to remove water from the coke oven gas to ≤1ppm. The other stream, as dehydration regeneration gas, first passes through the dehydration tower after heating for cold blowing, and then enters the first heater to be heated to 220°C. The high-temperature regeneration gas is heated and regenerated in the dehydration tower in the heating state, desorbing and removing water from the adsorbent. After being cooled by the first cooler to about 40°C, the regeneration gas passes through the second gas-liquid separator to separate free water, and then returns to the first pipeline to merge with the first stream of raw gas and enter the dehydration tower in the adsorption state.

[0085] The dried and purified gas exiting the dehydration tower in an adsorption state enters the mercury removal tower to remove mercury from the coke oven gas to ≤0.01μg / m³. 3 .

[0086] After mercury removal, the coke oven gas enters a purification tower in an adsorption state, where impurities such as carbon dioxide and heavy hydrocarbons are removed to a concentration of ≤20 ppm for carbon dioxide and ≤10 ppm for heavy hydrocarbons. Pressure swing adsorption (PSA) is used for coke oven gas purification. The purified regeneration gas comes from the nitrogen mains or nitrogen-rich gas from the liquefaction unit. The purification tower, having just finished its adsorption state, is first depressurized via a pressure relief valve. The regeneration gas is then heated to 220°C by a second heater. This high-temperature regeneration gas enters the purification tower in its regeneration state, where it is heated and regenerated, removing carbon dioxide and heavy hydrocarbons from the adsorbent. The regeneration gas, after being desorbed, is cooled to approximately 40°C by a second cooler before being sent to the downstream unit. After hot blowing, the cold regeneration gas enters the purification tower, which has just finished its hot blowing state, for cold blowing. The cold-blown gas is then cooled by a second cooler before being sent to the downstream unit.

[0087] After the cold blowing is completed, the purified gas pressurizes the purification tower, which has just finished the regeneration process, through the pressurization valve. After pressurization, the purification tower enters the adsorption state. The coke oven gas exiting the purification tower passes through a dust filter to remove dust and other impurities before entering the downstream liquefaction cold box unit.

[0088] Table 2 Composition of Coke Oven Gas (Part 1)

[0089] Components <![CDATA[H2]]> <![CDATA[CH4]]> <![CDATA[H2O]]> <![CDATA[N2]]> <![CDATA[CO2]]> <![CDATA[C6 + ]]> Hg Composition mol% 36.172 57.885 0.353 5.59 300ppm 50ppm <![CDATA[0.1μg / m 3 ]]>

[0090] As can be seen from Examples 1 and 2 above, this application can purify coke oven gas with different impurity contents from the upstream methanation unit to a water content ≤1ppm and a mercury content ≤0.01μg / m³ by adjusting the flow rate, pressure, and temperature of the raw gas entering the first gas-liquid separator. 3 It has a carbon dioxide content of ≤20ppm and a heavy hydrocarbon content of ≤10ppm, exhibits high resistance to component fluctuations, and can adapt to fluctuations in impurities in coke oven gas after methanation.

[0091] In summary, this application, by setting up a first gas-liquid separator, a dehydration tower, a mercury removal tower, a purification tower, and a dust filter connected sequentially along the flow direction of the raw gas, can effectively remove impurities such as water, carbon dioxide, mercury, and heavy hydrocarbons from the coke oven gas from the methanation unit, thereby ensuring that the composition of the purified gas is stable and meets the operating conditions of the downstream liquefaction cold box.

[0092] By setting up multiple dehydration towers in parallel, with at least two dehydration towers operating in different states; and setting up multiple purification towers, with at least two purification towers operating in different states, the adsorption and desorption of different dehydration towers and purification towers are staggered, thereby achieving continuous operation of the system and improving the operating efficiency and stability of the equipment.

[0093] In addition, by installing programmable valves on each connecting pipe of the purification unit, and connecting the programmable valves to the system controller, the adsorption cycle of each adsorption component and the amount of regeneration gas can be adjusted in real time according to online monitoring data, thereby improving the flexibility and intelligence of the purification unit, ensuring the purification effect of coke oven gas, and improving the operational stability of downstream equipment.

[0094] It is understood that those skilled in the art can make equivalent substitutions or changes based on the technical solution and concept of this application, and all such substitutions or changes should fall within the protection scope of the appended claims.

Claims

1. A coke oven gas purification apparatus, characterized by, The purification device includes: The first gas-liquid separator has its inlet end connected to the gas source of the raw material gas. A dehydration tower, the bottom of which is connected to the outlet of the first gas-liquid separator via a first pipe; A mercury removal tower is located downstream of the dehydration tower, and the inlet end of the mercury removal tower is connected to the top of the dehydration tower via a fourth pipe. A purification tower is located downstream of the mercury removal tower, and the bottom of the purification tower is connected to the outlet end of the mercury removal tower. A dust filter is located downstream of the purification tower. The inlet end of the dust filter is connected to the top of the purification tower via a fifth pipe, and the outlet end of the dust filter is used to discharge the purified gas.

2. The purification plant of the coke oven gas according to claim 1, characterized by the fact that, The dehydration tower is provided in at least two, and multiple dehydration towers are arranged in parallel; and / or, The purification tower is provided in at least two parts, and multiple purification towers are arranged in parallel.

3. The purification plant of the coke oven gas according to claim 2, characterized by the fact that, The purification device includes: A first heater, the inlet end of which is connected to the fourth pipe, and the outlet end of which is connected to the fourth pipe; The second gas-liquid separator has its inlet end connected to the first pipeline via a second pipeline, and its outlet end connected to the first pipeline via a third pipeline. A first cooler, located on the second pipe, is used to cool the raw material gas discharged from the bottom of the dehydration tower.

4. The purification plant of the coke oven gas according to claim 3, characterized by the fact that, The purification device includes: The second heater has its inlet connected to the regeneration gas source via a sixth pipe, and its outlet connected to the top of the purification tower via a seventh pipe. The regenerated gas source is connected to the top of the purification tower via the eleventh pipe.

5. The purification plant of the coke oven gas according to claim 4, characterized by the fact that, The purification device further includes: The second cooler has its inlet end connected to the bottom of the purification tower via the eighth pipe, and its inlet end is connected to the eleventh pipe via the ninth pipe.

6. The purification plant of the coke oven gas according to claim 5, characterized by the fact that, The top of the mercury removal tower is connected to the bottom of the purification tower via a twelfth pipe, and the twelfth pipe is connected to the inlet of the second cooler via a thirteenth pipe; The purification device also includes a pressure relief valve, which is located in the thirteenth pipeline and is used to relieve pressure on the purification tower after adsorption.

7. The purification plant of the coke oven gas according to claim 5, characterized by the fact that, A tenth pipe is also connected between the purification tower and the dust filter. The two ends of the tenth pipe are respectively connected to the fifth pipe. A first programmable valve is provided between the inlet end of the tenth pipe and the purification tower. The outlet end of the tenth pipe is connected between the purification tower and the first programmable valve. The purification device also includes a pressurization valve, which is located in the tenth pipeline and is used to pressurize the regenerated purification tower.

8. The coke oven gas purification apparatus according to claim 1, characterized in that, The purification device is equipped with programmable valves on its connecting pipes.

9. The coke oven gas purification apparatus according to claim 4, characterized in that, The regenerated gas includes at least one of nitrogen and nitrogen-enriched gas.

10. The coke oven gas purification apparatus according to claim 1, characterized in that, The purification device further includes: A carbon dioxide monitor, located downstream of the purification tower, is used to monitor the carbon dioxide content in the purified gas obtained after purification; and / or, A moisture monitor is installed at the outlet of the dehydration tower and is used to monitor the moisture content in the dehydrated raw gas.

Images