Coke oven gas purification and debenzolization device and method

Abstract

The invention discloses a coke oven gas purification and debenzolization device and method.The coke oven gas purification and debenzolization device comprises a pre-treatment section and a post-treatment section, rich oil washed in the pre-treatment section enters the post-treatment section to be treated, the pre-treatment section comprises a first treatment section and a second treatment section, and the first treatment section and the second treatment section are arranged in series; the post-treatment section comprises a tubular furnace and a regenerator connected with the tubular furnace, the tubular furnace is connected with a debenzolization tower in series, the bottom of the debenzolization tower is connected with a dephlegmator through a pipeline, the dephlegmator is connected with a condensation cooler through a pipeline, and the condensation cooler is connected with an oil-water separator through a pipeline; the first treatment section comprises a final cooling tower and a benzene washing tower connected with the final cooling tower in series, the second treatment section comprises a water washing tower and an acid washing tower which are connected in series, the acid washing tower is connected with a desulfurization process or a gas holder in series, an inlet connected with the final cooling tower is connected with a coke oven gas pipeline, the final cooling tower cools coke oven gas, and the cooled coke oven gas is subjected to washing oil absorption through the benzene washing tower.

Description

Technical Field

[0001] This invention belongs to the field of industrial coke oven technology, specifically relating to a coke oven gas purification and benzene removal device and method. Background Technology

[0002] Coke oven gas benzene removal technology has always been a key factor restricting the production of hydrogen from coke oven gas, especially given the high benzene impurity content in coke oven gas. Effective benzene removal has become a bottleneck in coke oven gas hydrogen production technology. Benzene impurities in coke oven gas not only clog the hydrogenation reactor bed, desulfurization tower bed, and converter tubes, but also prevent the process from operating stably for extended periods. Furthermore, the cost of replacing catalysts and desulfurizing agents is relatively high, placing an economic burden on enterprises. The coke oven gas benzene removal process mainly uses wash oil to absorb benzene compounds from the coke oven gas, followed by benzene removal through atmospheric or negative pressure steam distillation. This process is complex, energy-intensive, and involves high operating temperatures, making it highly susceptible to combustion or explosion, posing a significant hazard to enterprises and a persistent management challenge.

[0003] In view of the above factors, a coke oven gas purification and benzene removal device and method are provided to solve the above problems. Summary of the Invention

[0004] The purpose of this invention is to provide a coke oven gas purification and benzene removal device and method to solve the problems mentioned in the background art.

[0005] The objective of this invention is achieved through the following technical solution: a coke oven gas purification and benzene removal device, comprising a pretreatment section and a posttreatment section, wherein the rich oil washed in the pretreatment section enters the posttreatment section for further processing;

[0006] The pre-processing section includes a first processing section and a second processing section, which are connected in series.

[0007] The post-processing section includes a tubular furnace and a regenerator connected to the tubular furnace. The tubular furnace is connected in series with a benzene removal tower. The bottom of the benzene removal tower is connected to a separator via a pipeline. The separator is connected to a condenser via a pipeline. The condenser is connected to an oil-water separator via a pipeline.

[0008] Furthermore, the first processing section includes a final cooling tower and a benzene washing tower connected in series with the final cooling tower, and the second processing section includes a water washing tower and an acid washing tower connected in series, wherein the acid washing tower is connected in series with a desulfurization process or a gas holder.

[0009] Furthermore, the inlet of the final cooling tower is connected to the coke oven gas pipeline. The final cooling tower cools the coke oven gas to 25-28°C, and the cooled coke oven gas is then washed and absorbed by the benzene washing tower.

[0010] Furthermore, a collection pool is provided on the outside of the regenerator, which is led out from the oil-rich pipeline heated by the tubular furnace and connected to the regenerator.

[0011] Furthermore, the fractionator and the condenser are supported by a steel structure. The crude benzene vapor from the top of the benzene removal tower enters the fractionator, and some of the water vapor is condensed and enters the condenser. The crude benzene and water flow from the bottom of the condenser into the oil-water separator for separation.

[0012] Furthermore, the oil-water separator is connected to a crude benzene storage tank via a pipeline, and the crude benzene storage tank is equipped with an external discharge pipeline, on which a product pipeline pump is installed.

[0013] Furthermore, the post-processing section also includes a lean-rich oil heat exchanger, which is connected to the benzene removal tower via a pipeline. The gas from the benzene removal tower is heated and then enters the lean-rich oil heat exchanger, where it is heated by hot lean oil before entering the tubular furnace.

[0014] Furthermore, the separator is connected to both the heavy separator water separator and the light separator water separator, and the heavy separator water separator and the light separator water separator are connected in series to the oil-water separator.

[0015] A method for applying a coke oven gas purification and benzene removal device includes the following steps;

[0016] The first processing section includes a final cooling tower and a benzene washing tower connected in series with the final cooling tower. The inlet of the final cooling tower is connected to the coke oven gas pipeline. The final cooling tower cools the coke oven gas to 25-28°C. The cooled coke oven gas is washed and absorbed by the benzene washing tower. The processed coke oven gas is then washed by a water washing tower and an acid washing tower. The acid washing tower is connected in series with a desulfurization process or a gas holder.

[0017] The water washing tower is an air-jet tower with multi-stage spraying. Each stage has a gas distributor at the bottom (current technology, with a tray-type gas-liquid distributor or a perforated tray-type liquid distributor at the bottom and an initial gas-liquid distributor at the top). The coke oven gas cleaned in the water washing tower enters the acid washing tower, where the washing liquid and the gas being cleaned flow in opposite directions. The acid is sprayed from the top / bottom of the acid washing tower, while the gas being cleaned flows upwards from the bottom. This counter-current flow ensures sufficient contact between the acid and the gas being cleaned, improving cleaning efficiency.

[0018] After the benzene washing tower (existing technology disclosed, not described in detail here) absorbs the washing oil, the rich oil formed after benzene washing is pumped to a pressure of 0.03-0.08 MPa and first enters the separator, where it is heated by gas from the benzene stripping tower. Then it enters the rich-lean oil heat exchanger and is heated by the hot lean oil before entering the tubular furnace. The heated rich oil enters the benzene stripping tower, and the hot lean oil flows from the bottom of the benzene stripping tower through the rich-lean oil heat exchanger into the hot lean oil tank at the bottom of the benzene stripping tower at a temperature of about 120°C. Then it is pumped to the lean oil cooler for cooling and returned to the benzene washing tower for recycling.

[0019] The crude benzene vapor from the top of the benzene stripping tower enters the fractionator, where the temperature drops from 170℃-180℃ to about 90℃. Some of the water vapor is condensed and then enters the condenser. The crude benzene and water flow from the bottom of the condenser into the oil-water separator for separation. The crude benzene from the oil-water separator enters the crude benzene storage tank, while the light fractionation oil and heavy fractionation oil enter the oil-water separator for separation.

[0020] To ensure the quality of the washed oil, 1%-2% of the rich oil is drawn from the rich oil pipeline heated by the tubular furnace and fed into the regenerator. The superheated steam from the tubular furnace is used for steam blowing. Water vapor is discharged from the top of the regenerator, and the oil vapor and crude benzene vapor enter the benzene removal tower together. The residue at the bottom of the regenerator is discharged periodically.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] The present invention heats the rich oil in a tubular furnace at a temperature higher than 160°C, achieving a high degree of benzene removal. The crude benzene content in the lean oil can reach approximately 0.1%, thereby reducing the loss of crude benzene. The crude benzene recovery rate is high; after the coke oven gas undergoes the crude benzene recovery process, the gas can be purified and then transported through gas pipelines for user use, further yielding a valuable basic raw material for the organic synthesis industry. Attached Figure Description

[0023] Figure 1 This is a schematic diagram showing the connection between the pre-processing section and the post-processing section of the present invention;

[0024] Figure 2 This is a schematic diagram of the overall connection of the pre-processing section of the present invention;

[0025] Figure 3 This is the present invention. Figure 2 A schematic diagram showing the connection between the desulfurization process or the gas holder;

[0026] Figure 4 This is a schematic diagram of the overall connection of the post-processing section of the present invention;

[0027] Figure 5 This is a schematic diagram showing the unfolded connection of the pre-processing section and the post-processing section of the present invention;

[0028] Figure 6 This is a schematic cross-sectional view of the acid washing tower in the pretreatment section of this invention;

[0029] Figure 7 This is a schematic cross-sectional view of the water washing tower in the pretreatment section of this invention. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0031] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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 direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0033] like Figure 1-7 As shown, a coke oven gas purification and benzene removal device includes a pretreatment section 1 and a posttreatment section 2. The rich oil washed in the pretreatment section 1 enters the posttreatment section 2 for further processing.

[0034] The pre-processing section 1 includes a first processing section 3 and a second processing section 4, which are connected in series.

[0035] The post-processing section 2 includes a tubular furnace 5 and a regenerator 6 connected to the tubular furnace 5. The tubular furnace 5 is connected in series with a benzene removal tower 7. The bottom of the benzene removal tower 7 is connected to a shrinkage unit 8 through a pipeline. The shrinkage unit 8 is connected to a condenser 9 through a pipeline. The condenser 9 is connected to an oil-water separator 10 through a pipeline.

[0036] The fractionator performs partial condensation, achieving the separation of water vapor and the reflux of heavy components. The crude benzene vapor and the remaining water vapor that come out from the top of the fractionator, after being enriched, enter the condenser cooler, where they are all condensed into liquid.

[0037] In the separator, the gas flows through the tube side (or shell side), while the cooling water (usually low-temperature water or chilled water) flows through the other side. The gas is cooled, and components such as steam and tar condense. The condensate is discharged along with the gas and enters the oil-water separator for oil and water separation.

[0038] A 6mm steel plate is laid on the outside of the furnace shell, and the original support is used to weld and seal it to form a new furnace shell. Refractory mortar with a thickness of about 200mm is poured between the steel plate and the furnace shell.

[0039] The coke oven gas is treated to remove benzene through a pretreatment section 1 and a posttreatment section 2.

[0040] In order to remove ammonia from coke oven gas by water washing and acid washing under the condition of use, the first treatment section 3 includes a final cooling tower 11 and a benzene washing tower 12 connected in series with the final cooling tower 11. The second treatment section 4 includes a water washing tower 13 and an acid washing tower 14 connected in series. The acid washing tower 14 is connected in series with a desulfurization process or a gas holder.

[0041] The benzene washing tower adopts a multi-stage spray system. Based on the existing benzene washing tower technology, four new swirl nozzles (60° angle) are added to the original six nozzles to form a double-layer spray structure. The upper layer is 12m high and the lower layer is 8m high. Technical effect: spray coverage rate increases from 75% to 98%, and gas residence time is extended to 8s (originally 5s).

[0042] Four nozzle bases (made of 316L stainless steel) were added to the 8m high platform of the benzene washing tower, and swirl nozzles (model XWH-60, flow rate 15m³ / h) were installed. 3 / h), and set up a dual-path control system, with the original nozzles (lower layer) spraying continuously, and the added nozzles (upper layer) spraying intermittently (on / off).

[0043] =10min / 5min).

[0044] Before the coke oven gas enters the desulfurization process or gas holder, water washing and acid washing remove ammonia from the coke oven gas, which can prevent the alkaline gas from reacting with the acidic desulfurization liquid and consuming the desulfurization liquid. At the same time, water washing and acid washing can obtain ammonia water and ammonium salts such as ammonium sulfate, respectively.

[0045] The pickling tower is a spray-type pickling tower, which uses sulfuric acid as the absorbent to absorb ammonia from coke oven gas. The washing liquid for pickling is an inorganic acid, such as sulfuric acid, nitric acid or hydrochloric acid. The above-mentioned inorganic acid can achieve rapid and effective absorption of ammonia. The inorganic acid is preferably sulfuric acid, and the mass concentration of sulfuric acid used for industrial ammonia absorption is 20%-40%.

[0046] To facilitate pre-treatment and recovery of rich oil and one-step treatment of flue gas during operation, the inlet of the final cooling tower 11 is connected to the coke oven gas pipeline. The final cooling tower 11 cools the coke oven gas, and the cooled coke oven gas is washed and absorbed by the benzene washing tower 12.

[0047] Coke oven gas is cooled by a final cooling tower to improve the efficiency of the benzene washing tower in absorbing benzene compounds from the coke oven gas.

[0048] To ensure sufficient heat is provided during operation, enabling the regenerator to effectively remove polymers from the wash oil, maintain its quality, and extend its service life, a collection tank 13 is provided on the outside of the regenerator 6. The rich oil pipeline heated by the tubular furnace 5 is led out and connected to the regenerator 6.

[0049] The regenerator typically uses indirect steam or its own heat to distill off the lighter components from this lean oil portion and return them to the system, while the residual residue is periodically discharged. The tubular furnace provides the basic heat source for the entire system, ensuring the regenerator can operate normally.

[0050] To facilitate oil-water separation and crude benzene storage during operation, the separator 8 and the condenser 9 are supported by a steel structure. Crude benzene vapor from the top of the benzene removal tower 7 enters the separator 8, and some water vapor is condensed and enters the condenser 9. Crude benzene and water flow from the bottom of the condenser 9 into the oil-water separator 10 for separation.

[0051] The oil-water separator 10 is connected to the crude benzene storage tank 15 via a pipeline. The crude benzene storage tank 15 is equipped with an external discharge pipeline, and a product pipeline pump is installed on the external discharge pipeline.

[0052] In order to utilize the heat carried by the high-temperature lean oil to preheat the low-temperature rich oil during operation, thereby significantly reducing the energy consumption of the entire system and improving economic efficiency, the post-processing section 2 also includes a lean-rich oil heat exchanger 16. The lean-rich oil heat exchanger 16 is connected to the benzene removal tower 7 through a pipeline. After being heated by the gas from the benzene removal tower 7, the gas enters the lean-rich oil heat exchanger 16 and is heated by the hot lean oil before entering the tubular furnace 5.

[0053] In a shell-and-tube heat exchanger, the high-temperature lean oil flows in the tube side or shell side, while the low-temperature rich oil flows in the shell side or tube side in the opposite direction. The two exchange heat indirectly through the metal tube walls, resulting in a decrease in the temperature of the lean oil and an increase in the temperature of the rich oil.

[0054] The separator 8 is connected to the heavy separator water separator 17 and the light separator water separator 18 respectively. The heavy separator water separator 17 and the light separator water separator 18 are connected in series to the oil-water separator 10.

[0055] A method for applying a coke oven gas purification and benzene removal device includes the following steps;

[0056] The first processing section includes a final cooling tower and a benzene washing tower connected in series with the final cooling tower. The inlet of the final cooling tower is connected to the coke oven gas pipeline. The final cooling tower cools the coke oven gas to 25-28°C. The cooled coke oven gas is washed and absorbed by the benzene washing tower. The processed coke oven gas is then washed by a water washing tower and an acid washing tower. The acid washing tower is connected in series with a desulfurization process or a gas holder.

[0057] The water washing tower is an air-spray tower with multi-stage spraying. Each stage has a gas distributor at the bottom. The coke oven gas cleaned by the water washing tower enters the acid washing tower, where the washing liquid and the gas being cleaned flow in opposite directions. The acid is sprayed from the top and bottom of the acid washing tower, with two sets of spaced demisters. The gas being cleaned flows upward from the bottom of the tower. This counter-current method ensures full contact between the acid and the gas being cleaned, improving cleaning efficiency.

[0058] The demister layer employs stainless steel baffle plate and corrugated plate demisters. After the benzene washing tower absorbs the washing oil, the rich oil formed after washing is pumped to a pressure of 0.03-0.08 MPa and first enters the separator, where it is heated by the gas from the benzene removal tower. Then, it enters the rich-lean oil heat exchanger and is heated by the hot lean oil before entering the tubular furnace. The heated rich oil enters the benzene removal tower, while the hot lean oil flows from the bottom of the benzene removal tower through the rich-lean oil heat exchanger into the hot lean oil tank at the bottom of the benzene removal tower at a temperature of approximately 120°C. Then, it is pumped to the lean oil cooler for cooling and returned to the benzene washing tower for recycling.

[0059] The crude benzene vapor from the top of the benzene stripping tower enters the fractionator, where the temperature drops from 170℃-180℃ to about 90℃. Some of the water vapor is condensed and then enters the condenser. The crude benzene and water flow from the bottom of the condenser into the oil-water separator for separation. The crude benzene from the oil-water separator enters the crude benzene storage tank, while the light fractionation oil and heavy fractionation oil enter the oil-water separator for separation.

[0060] To ensure the quality of the washed oil, 1%-2% of the rich oil is drawn from the rich oil pipeline heated by the tubular furnace and fed into the regenerator. The superheated steam from the tubular furnace is used for steam blowing. Water vapor is discharged from the top of the regenerator, and the oil vapor and crude benzene vapor enter the benzene removal tower together. The residue at the bottom of the regenerator is discharged periodically.

[0061] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0062] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A coke oven gas purification and benzene removal device, characterized in that: It includes a pretreatment section (1) and a posttreatment section (2), wherein the oil-rich material washed in the pretreatment section (1) enters the posttreatment section (2) for further processing; The preprocessing section (1) includes a first processing section (3) and a second processing section (4), which are connected in series. The post-processing section (2) includes a tubular furnace (5) and a regenerator (6) connected to the tubular furnace (5). The tubular furnace (5) is connected in series with a benzene removal tower (7). The bottom of the benzene removal tower (7) is connected to a separator (8) through a pipeline. The separator (8) is connected to a condenser (9) through a pipeline. The condenser (9) is connected to an oil-water separator (10) through a pipeline.

2. The coke oven gas purification and benzene removal device according to claim 1, characterized in that: The first processing section (3) includes a final cooling tower (11) and a benzene washing tower (12) connected in series with the final cooling tower (11). The second processing section (4) includes a water washing tower (13) and an acid washing tower (14) connected in series. The acid washing tower (14) is connected in series with a desulfurization process or a gas holder.

3. The coke oven gas purification and benzene removal device according to claim 2, characterized in that: The inlet of the final cooling tower (11) is connected to the coke oven gas pipeline. The final cooling tower (11) cools the coke oven gas, and the cooled coke oven gas is washed and absorbed by the benzene washing tower (12).

4. The coke oven gas purification and benzene removal device according to claim 3, characterized in that: A collection pool (13) is provided on the outside of the regenerator (6), which is led out by the oil-rich pipeline heated by the tubular furnace (5) and connected to the regenerator (6).

5. The coke oven gas purification and benzene removal device according to claim 4, characterized in that: The fractionator (8) and the condenser (9) are supported by a steel structure. The crude benzene vapor from the top of the benzene removal tower (7) enters the fractionator (8), and some water vapor is condensed and enters the condenser (9). Crude benzene and water flow from the bottom of the condenser (9) into the oil-water separator (10) for separation.

6. The coke oven gas purification and benzene removal device according to claim 5, characterized in that: The oil-water separator (10) is connected to the crude benzene storage tank (15) via a pipeline. The crude benzene storage tank (15) is equipped with an external discharge pipeline, and a product pipeline pump is installed on the external discharge pipeline.

7. The coke oven gas purification and benzene removal device according to claim 6, characterized in that: The post-processing section (2) also includes a lean and rich oil heat exchanger (16), which is connected to the benzene removal tower (7) through a pipeline. After being heated by the gas from the benzene removal tower (7), the gas enters the lean and rich oil heat exchanger (16) and is heated by the hot lean oil before entering the tubular furnace (5).

8. The coke oven gas purification and benzene removal device according to claim 7, characterized in that: The separator (8) is connected to the heavy separator water separator (17) and the light separator water separator (18) respectively. The heavy separator water separator (17) and the light separator water separator (18) are connected in series to the oil-water separator (10).

9. A method for applying the coke oven gas purification and benzene removal device according to claim 8, characterized in that: Specifically, the steps are as follows; The first processing section includes a final cooling tower and a benzene washing tower connected in series with the final cooling tower. The inlet of the final cooling tower is connected to the coke oven gas pipeline. The final cooling tower cools the coke oven gas to 25-28°C. The cooled coke oven gas is washed and absorbed by the benzene washing tower. The processed coke oven gas is then washed by a water washing tower and an acid washing tower. The acid washing tower is connected in series with a desulfurization process or a gas holder. The water washing tower adopts an air spray tower, which is a multi-stage spray tower. Each stage is equipped with a gas distributor at the bottom. The coke oven gas cleaned by the water washing tower enters the acid washing tower. The water washing liquid and the gas being cleaned flow in opposite directions. The acid liquid is sprayed from the top / bottom of the acid washing tower, while the gas being cleaned flows upward from the bottom of the tower. This counter-current method allows the acid liquid and the gas being cleaned to come into full contact, improving the cleaning efficiency. After the benzene washing tower absorbs the washing oil, the rich oil formed after washing benzene is pumped to a pressure of 0.03-0.08MPa and first enters the separator, where it is heated by the gas from the benzene stripping tower. Then it enters the rich and lean oil heat exchanger and is heated by the hot lean oil before entering the tubular furnace. The heated rich oil enters the benzene stripping tower, and the hot lean oil flows from the bottom of the benzene stripping tower through the rich and lean oil heat exchanger into the hot lean oil tank at the bottom of the benzene stripping tower at a temperature of about 120℃. Then it is pumped to the lean oil cooler for cooling and sent back to the benzene washing tower for recycling. The crude benzene vapor from the top of the benzene stripping tower enters the fractionator, where the temperature drops from 170℃-180℃ to about 90℃. Some of the water vapor is condensed and then enters the condenser. The crude benzene and water flow from the bottom of the condenser into the oil-water separator for separation. The crude benzene from the oil-water separator enters the crude benzene storage tank, while the light fractionation oil and heavy fractionation oil enter the oil-water separator for separation. To ensure the quality of the washed oil, 1%-2% of the rich oil is drawn from the rich oil pipeline heated by the tubular furnace and fed into the regenerator. The superheated steam from the tubular furnace is used for steam blowing. Water vapor is discharged from the top of the regenerator, and the oil vapor and crude benzene vapor enter the benzene removal tower together. The residue at the bottom of the regenerator is discharged periodically.

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