Catalytic distillation device and application for heat recovery of raw coke oven gas and coal tar pretreatment

Abstract

The present invention discloses a catalytic distillation device and application for heat recovery of raw coke oven gas and coal tar pretreatment, comprising: a catalytic distillation column; the lower part of the catalytic distillation column is a washing area for mechanical impurities of raw coke oven gas; the upper part of the catalytic distillation column is a suspension bed catalytic distillation area, and a gas-phase material outlet is arranged in the catalytic distillation area. The gas-phase material outlet is connected to a heat exchanger through a pipeline. After being cooled by the heat exchanger, the material is connected to the material inlet in the middle of a gas-liquid separator through a pipeline. A gas-phase discharge port is arranged at the top of the gas-liquid separator, and a liquid-phase discharge port is arranged at the bottom of the gas-liquid separator. The liquid-phase discharge port is connected to the upper reflux port of the catalytic distillation column and an external discharge pipeline; the upper reflux port of the catalytic distillation column is connected to an oil-soluble suspension bed hydrogenation catalyst addition device. The device of the present invention can recover the heat of high-temperature raw coke oven gas while effectively pretreating coal tar, laying a foundation for subsequent processing.

Description

Technical Field

[0001] The present invention relates to a device and application for heat recovery of raw coal gas and coal tar pretreatment, belonging to the technical field of preparing liquid hydrocarbon mixtures and coal gas from coal. Background Art

[0002] In China, the distribution of energy resources is uneven, characterized by "rich in coal, short of oil, and scarce in gas", that is, coal resources are abundant, accounting for 94.3% of the proven reserves of fossil energy, and also reaching about 70% in the total primary energy consumption. Among the abundant coal resources, the reserves of low-rank coal are the largest, accounting for 55% of the proven reserves. In the utilization of low-rank coal, it is relatively difficult to be directly used as fuel, but it is a high-quality raw material for preparing liquid hydrocarbons from coal.

[0003] There are mainly two routes for preparing liquid hydrocarbons from low-rank coal. One is the direct coal liquefaction technology, which has a high cost. The other is the coal carbonization / coking technology. The basic principle is the pyrolysis reaction of low-rank coal. Its characteristics are simple and mature technology. The obtained coke or semi-coke is a high-quality fuel and raw materials such as reducing agents required in the metallurgical industry. At the same time, liquid hydrocarbons (i.e., coal tar) are obtained, and further processing can be used to produce liquid fuels and various chemical raw materials.

[0004] During the coal carbonization / coking process, the temperature of the discharged raw coal gas is high, generally reaching above 600°C, and generally accounting for about 37% of the heat output of the coke oven. The composition of the raw coal gas is complex, containing solid coke powder, complex mixed hydrocarbons, complex gas phase, water, etc. Although this gas has rich heat, the heat is difficult to recover and utilize. The main problems are the blockage, coking, corrosion, etc. of the heat exchange equipment. In traditional technologies, ammonia water is used for spray cooling, and all the heat therein is lost, resulting in high energy consumption of the device. Therefore, how to effectively recover the heat in the raw coal gas, especially how to solve the problems of equipment blockage, coking, etc. during heat recovery, is a matter of key concern in this field.

[0005] CN201310391012.7 discloses a waste heat recovery and utilization system for coke oven raw gas, which includes a heat transfer medium circulation system and a water replenishment system. The heat transfer medium circulation system includes a heat exchanger group, a steam drum, and a forced circulation pump. The water inlet of the heat exchanger group is connected to the water outlet of the steam drum through the forced circulation pump, and the water outlet of the heat exchanger group is connected to the water inlet of the steam drum. The steam outlet on the steam drum is connected to the external steam pipe network. The water replenishment system includes a buffer water tank, a water replenishment pump, a feed water pump, and a demineralized and deoxygenated water tank. The feed water pump is arranged between the buffer water tank and the demineralized and deoxygenated water tank, and the buffer water tank is connected to the steam drum through the water replenishment pump. By setting multiple parallel heat exchanger groups and adding a control system in this solution, when a certain heat exchanger group fails, it can be processed in time to increase the safety and reliability of the heat exchange system, improve the safe and normal operation of the system, and reduce the accident rate. However, due to the characteristics of the raw gas, coking and fouling of the heat exchanger group will inevitably occur quickly. Even in a parallel connection mode, when one group is under maintenance, it still brings great fluctuations and operation difficulties to normal operation.

[0006] CN201410692354.7 discloses a system and method for pyrolysis waste gas dust removal and oil cooling to recover tar, which includes a particle dust collector, an electrostatic precipitator, a tar refining tower, a gas cooling tower, and an electrostatic tar precipitator connected in sequence. In the present invention, a tar refining tower is arranged between the particle bed dust collector and the gas cooling tower, which makes full use of the heat of the gas itself. Through the "rectification principle", the collected tar is further dehydrated and refined. The process flow is short, and the obtained tar has a low water content and good quality. This solution directly uses the sensible heat carried by the pyrolysis gas as the heat source for rectifying the water-containing tar in the tar refining tower, realizing the efficient utilization of heat in the same tar recovery system, aiming to provide a new heat recovery process and method for the pyrolysis waste gas cooling and tar recovery and refining system. However, in this solution, by using methods such as particle dust collectors and electrostatic precipitators, for the raw gas that is prone to coking and generating sludge-like solids, the fouling and coking of the equipment are serious, and the operation cycle is greatly affected.

[0007] CN201911169496.4 discloses a coupling deep desulfurization system and method for coke oven raw gas and coke. By setting a high-temperature coke hydrogenation reactor, additional hydrogenation is not required, and the hydrogenation reaction of coke can be completed using the H2 rich in the raw gas itself, thereby transferring the sulfur in the coke to the gas. By setting a catalytic hydrogenation reactor and using a catalyst, the organic sulfur in the raw gas is almost completely converted into H2S, efficiently and deeply removing organic sulfur and inorganic sulfur in coke oven gas from the source, thus greatly reducing the sulfur content of coking benzene products and coke, improving the quality of benzene products and coke, and reducing the load and difficulty of subsequent fine desulfurization. This method is carried out at a high temperature (the coal tar component in the raw gas is in the gas phase), for example, the hydrogenation reactor needs to be controlled at 650 - 1000 °C. Under this condition, the coal tar component will further dehydrogenate (hydrogenation / dehydrogenation is reversible. Under certain conditions such as low temperature and high pressure, it is mainly hydrogenation, and under certain conditions such as high temperature and low pressure, it is mainly dehydrogenation), generating more unsaturated olefins, diolefins, aryl olefins and other coke-forming substances in hydrocarbons. Not only is no pretreatment carried out on the coal tar, but it also brings more serious coking problems to the subsequent coal tar processing.

[0008] CN201610213831.6 discloses a heat recovery system and method for raw gas from coke ovens based on washing and rectification. The raw gas is washed and rectified to remove heavy tar and coke powder, obtaining high-boiling oil products and high-temperature raw gas. The high-boiling oil products and / or high-temperature raw gas are heat-exchanged to generate high-pressure steam, and then the high-pressure steam is subjected to steam-water separation, and the separated steam is utilized. This system has high dust removal efficiency, stable operation, is not easily blocked, and can realize full recovery and utilization of heat. However, this system has the following deficiencies: (1) Although solid dust is basically removed by the washing method, solving the problem of equipment blockage caused by carrying coke powder, the bottom temperature of the washing and rectification tower is relatively high, and the problem that the high-boiling components in the raw gas are prone to coking at high temperatures has not been solved, still affecting the operation cycle of the device; (2) Based on the principle of the rectification tower of the plate tower, although a special structure of "perforated tray" (see paragraph 30 of its specification) is designed, the coking physical properties of the material remain unchanged, and its coking problem will still exist. After the equipment operates for a certain period of time, there will inevitably be a coking problem; (3) The coking characteristics of the obtained coal tar remain unchanged, and the problems of coking and equipment blockage in subsequent processing are still prominent.

[0009] Although the existing technology has conducted a lot of research on the heat utilization of raw gas from coke ovens, its coking characteristics have not been changed, there is no good solution to the coking problem, and the problem of affecting the stable operation of the device caused by coking has not been solved.

[0010] Coal tar is a liquid mixed hydrocarbon recovered from raw gas from coke ovens, with complex components and obvious coking tendency. The traditional method is to carry out hydrogenation under mild conditions to hydrogenate and saturate the easily coking diene and aryl olefin groups, alleviating the problems existing in subsequent processing.

[0011] CN200710034412.7 discloses a pretreatment method for coal tar. The coal tar is mixed with fractionated oil and aromatic hydrocarbons respectively to conduct a two-step extraction process to remove most of the impurities in the coal tar. The utilization rate of the coal tar by this method can reach 90%. When the pretreated coal tar is subjected to hydro-upgrading to produce fuel oil, it can delay the coking of the hydrocracking catalyst and extend the operation cycle of the device. However, this method still loses a relatively large amount of coal tar raw materials in the pretreatment step, and the two-step extraction requires steps with high energy consumption such as solvent recovery, resulting in a high operating cost.

[0012] CN200810030954.1 discloses a coal tar hydroprocessing technology, which includes: after the coal tar is pretreated to obtain a coal tar hydroprocessing feedstock; the obtained coal tar hydroprocessing feedstock enters a pre-hydrogenation fixed-bed reactor from bottom to top; the obtained pre-hydrogenation product oil enters a main hydrogenation fixed-bed reactor from top to bottom; the obtained main hydrogenation product oil enters a fractionation system to obtain a gasoline fraction, a diesel fraction and a light fuel oil fraction. This solution adopts an up-flow pre-hydrogenation fixed-bed reactor in series with a down-flow main hydrogenation fixed-bed reactor, changing the flow direction of the material in the process, increasing the residence time of the reaction material on the catalyst bed layer, and effectively inhibiting or slowing down the coking reaction of coal tar at high temperature and extending the continuous operation cycle of the coal tar hydroprocessing device. In this solution, the method of using up-flow hydrogenation to relieve coking has limited effect, and it can only have an effect on the blockage of the catalyst bed layer, and the problem that the coking product makes the catalyst activity ineffective still cannot be solved.

[0013] CN201010621125.8 discloses a combined hydrogenation method for coal tar and coking fractionated oil, including: (1) the coal tar raw material, the coking fractionated oil raw material and hydrogen enter a hydrotreating reactor to conduct a diene removal reaction; (2) the reaction effluent of the hydrotreating reactor and the material heated by a heating furnace of the reaction effluent of step (4) hydrocracking are directly mixed to reach the temperature required at the inlet of the hydrotreating reactor; (3) the reaction effluent of the hydrotreating reactor enters a separation system to separate out recycle hydrogen, a gasoline fraction, a diesel fraction and a heavy oil fraction; (4) the heavy oil fraction and recycle hydrogen in step (3) are mixed and enter a hydrocracking reactor, and the reaction effluent of the hydrocracking reactor is heated by a heating furnace and then directly mixed with the reaction effluent of the hydrotreating reactor and enters the hydrotreating reactor. This solution adopts a method of pre-hydrogenating and saturating dienes to solve the coking problem of the coal tar and coking fractionated oil hydrotreating device.

[0014] The unit for recovering coal tar from raw gas is independent of the subsequent processing units, and there are intermediate steps such as storage and transportation between them. During these steps, the precursors of coal tar coking form preliminary polymerization under the action of oxygen (there is a small amount of nitrogen in the raw gas, and it is inevitable to contact oxygen during storage and transportation) and active sulfur. These preliminary polymers are extremely prone to form coking substances when the temperature rises. Therefore, it is difficult to solve the coking problem of coal tar during subsequent processing, and the effect is not ideal. Summary of the Invention

[0015] In view of the deficiencies in the prior art, the present invention provides a catalytic distillation device for heat recovery of raw gas and pretreatment of coal tar. The device of the present invention organically combines the work that was previously completed in two units for heat recovery of raw gas and pretreatment of coal tar into one device. While recovering the heat of the raw gas, it changes the coking characteristics of coal tar, ensures the stable operation of the heat recovery device, and at the same time effectively pre-treats the coal tar for the subsequent processing unit, effectively solving the coking problem during the subsequent processing of coal tar, and keeping the coal tar free from the influence of foreign components on subsequent processing.

[0016] The catalytic distillation device for heat recovery of raw gas and pretreatment of coal tar according to the present invention includes the following:

[0017] (1) A catalytic distillation column;

[0018] (2) The lower part of the catalytic distillation column is a washing area for mechanical impurities in the raw gas, and a raw gas inlet is provided below the washing area for mechanical impurities.

[0019] (3) The upper part of the catalytic distillation column is a suspension bed catalytic distillation area. A gas-phase material outlet is provided in the catalytic distillation area. The gas-phase material outlet is connected to a heat exchanger through a pipeline. After being cooled by the heat exchanger, the material is connected to the material inlet in the middle of a gas-liquid separator through a pipeline. A gas-phase discharge port is provided at the top of the gas-liquid separator, and a liquid-phase discharge port is provided at the bottom of the gas-liquid separator. The liquid-phase discharge port is connected to the upper reflux port of the catalytic distillation column and an external discharge pipeline.

[0020] (4) The upper reflux port of the catalytic distillation column is connected to an oil-soluble suspension bed hydrogenation catalyst addition device.

[0021] In the device of the present invention, the catalytic distillation column is of a vertical cylindrical structure and can be designed according to conventional techniques in the art.

[0022] In the device of the present invention, the washing area for mechanical impurities adopts a spray-type gas-liquid contact member or a tray-type gas-liquid contact member. The material in this area contains mechanical impurities, and the gas-liquid contact member should consider anti-blocking properties, and a spray-type structure is preferred. When adopting a tray-type structure, a structure in which the tray surface does not accumulate liquid-phase material can be used, that is, the downcomer is close to the tray surface, and the gas and liquid phases are in reverse contact within the downcomer.

[0023] In the device of the present invention, a discharge material pipeline is provided at the bottom of the mechanical impurity washing zone, a circulation pipeline is provided for recycling part of the discharged material back to the mechanical impurity washing zone, and a filtering device is provided for removing mechanical impurities from the discharged material and / or the circulating material.

[0024] In the apparatus of the present invention, the suspended bed catalytic distillation zone utilizes tray-type or packing-type gas-liquid contact members. A gaseous material outlet is provided in the upper middle portion of the suspended bed catalytic distillation zone or at the top of the catalytic distillation tower. To facilitate the removal of the gaseous material, a gaseous material collection device, such as a gas collecting tray, may be provided at the outlet. The above design can be based on conventional techniques in the art.

[0025] In the device of the present invention, the heat exchanger can be any structure of a shell-and-tube heat exchanger, a spiral tube heat exchanger, or a plate heat exchanger, and can be designed according to conventional techniques in the art.

[0026] The present invention provides an application of a raw gas heat recovery and coal tar pretreatment catalytic distillation device. The raw gas derived from a coking device or a coal dry distillation device directly enters a catalytic distillation tower, and coal tar pretreatment and fractionation are performed while heat is recovered.

[0027] In the application of the present invention, the coking device or coal dry distillation device is a device that uses coal as raw material, performs heat treatment, and produces coke, semi-coke, and by-products coal tar and coal gas. The raw coal gas temperature is 450-850°C, preferably 600-800°C.

[0028] In the present invention, the operating temperature of the mechanical impurity scrubbing zone is 350-550°C, preferably 380-500°C, and most preferably 400-450°C. The operating temperature is controlled by introducing aqueous ammonia into the zone. The concentration of the introduced aqueous ammonia can be any, preferably 30%-70% saturation at room temperature.

[0029] In the application of the present invention, the catalytic distillation tower is operated under normal pressure.

[0030] In the application of the present invention, the temperature of the gaseous material drawn out from the catalytic distillation zone of the catalytic distillation tower is 250-450°C, preferably 300-400°C.

[0031] In the application of the present invention, when gas phase is extracted in the catalytic distillation zone, the operating temperature at the top of the catalytic distillation tower is above 110°C, preferably 110-250°C, and most preferably 120-150°C. The principle of controlling the top operating temperature is to prevent water vapor from condensing and liquefying within the catalytic distillation tower.

[0032] In the application of the present invention, when the gaseous material is drawn out from the top of the catalytic distillation tower, the operating temperature of the top of the tower is 250-450°C, preferably 300-400°C.

[0033] In the application of the present invention, the oil-soluble suspension bed hydrogenation catalyst is added to the reflux material at the top of the catalytic distillation column. The suspension bed hydrogenation catalyst contains substances of at least one element in Group VIB and Group VIII of the periodic table. The suspension bed hydrogenation catalyst is a substance containing at least one element among cobalt, molybdenum, nickel, tungsten, and iron. Calculated by element weight, the addition amount of the suspension bed hydrogenation catalyst additive is 10 - 5000 μg / g, preferably 50 - 3000 μg / g, and most preferably 100 - 2000 μg / g. The oil-soluble suspension bed hydrogenation catalyst is one or several of the organic compounds containing cobalt, molybdenum, nickel, tungsten, and iron.

[0034] The oil-soluble suspension bed hydrogenation catalyst can adopt any products in the existing technologies in the art, such as the oil-soluble suspension bed hydrogenation catalysts disclosed in CN01106013.1, CN201410216485.8, CN202010553349.3, CN201711137478.9, CN201811388624.X, etc. The advantage of the oil-soluble suspension bed hydrogenation catalyst is that it does not have any adverse effects on the operation of the distillation zone. The selected requirements are substances with high activity, low dosage, low cost, and little impact on subsequent processing, and at the same time, it does not vaporize under the conditions of the catalytic distillation zone and remains in the liquid phase.

[0035] The present invention aims at heat recovery of raw coke oven gas and simultaneous pretreatment of coal tar, achieving the following technical effects: (1) The heat recovery of raw coke oven gas and the pretreatment of coal tar are organically coupled, changing the pretreatment method in the subsequent coal tar processing unit in the prior art, realizing synchronous pretreatment during coal tar recovery, solving the problems of stable operation such as coking in the heat recovery device of raw coke oven gas, and at the same time solving the problem of the formation of coke precursors in the section between coal tar recovery and subsequent processing, which exacerbates coking, and simplifies the process and equipment of the subsequent processing unit; (2) The catalytic distillation method is adopted, in which "catalytic" uses an oil-soluble suspension bed hydrogenation catalyst, which has no impact on "distillation". The oil-soluble suspension bed hydrogenation catalyst is added from the top of the tower and penetrates from the top to the bottom of the tower under the operation mode of the distillation tower. The utilization rate of the catalyst is high, and the catalytic action continuously occurs from the top (low temperature) to the bottom (high temperature) of the tower, which is beneficial to the full play of the catalyst activity, reduces the usage amount, has a prominent effect on the hydrotreating of coal tar, solves the coking problems of the distillation tower and heat exchanger, and can ensure long-term high operation; (3) Although suspension bed hydrogenation is a method with relatively weak hydrogenation effect, before the formation of coke precursors during the subsequent storage and transportation of coal tar, simple suspension bed hydrogenation can effectively hydrogenate diene and arene groups, which is easier and more effective than in the coal tar hydrogenation unit; (4) The process is simple. Utilizing the state and properties of coal tar in raw coke oven gas and the hydrogen existing in raw coke oven gas, multiple functions such as heat recovery, coal tar recovery, and coal tar pre-hydrotreating are achieved in one process, which is beneficial to reducing equipment investment; (5) Although the suspension bed hydrogenation process and catalyst belong to the prior art in this field, the main application purpose is to hydrocrack heavy hydrocarbons to obtain light hydrocarbon products. Due to the relatively low hydrogenation efficiency of the suspension bed hydrogenation technology, there is no prior art applying suspension bed hydrogenation to the pretreatment of coal tar. And in the method of the present invention, suspension bed hydrogenation is not directly used for the pretreatment of coal tar after recovery, but pretreatment is carried out simultaneously during the heat recovery process of coal tar recovery. And because the preliminary formation of coke polymerization precursors during treatment, storage, and transportation is avoided, pretreatment is carried out, and the fouling and coking on the surface of the heat exchanger are avoided, achieving better pretreatment results with a relatively poor hydrogenation effect; (6) An appropriate amount of ammonia water is introduced into the mechanical impurity washing area and cooled appropriately. The alkalinity of ammonia is beneficial to inhibiting the polymerization and coking tendency of coke precursors in high-temperature raw coke oven gas, and to a certain extent solves the problem that high-boiling components in raw coke oven gas are prone to coking at high temperatures, ensuring the operation cycle of the device; (7) The coal tar fractionated from the catalytic distillation section of the catalytic distillation tower does not introduce foreign components, which is beneficial to subsequent processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 FIG. is a schematic structural diagram of a catalytic distillation device for heat recovery of raw coke oven gas and pretreatment of coal tar according to the present invention.

[0037] Figure 2This is another structural schematic diagram of the catalytic distillation device for waste gas heat recovery and coal tar pretreatment in the present invention. Detailed implementation manners

[0038] The present invention will be further described below through specific implementation manners, but the protection scope of the present invention is not limited.

[0039] In the present invention: The waste gas is led out from the coking device or the coal carbonization device. The coking device or the coal carbonization device can be any existing technology in the field. Coking usually refers to high-temperature coking, and the temperature can reach 900 - 1100 °C. Carbonization includes medium-temperature carbonization (660 - 750 °C), low-temperature carbonization (500 - 580 °C), etc. The coal is heated and decomposed under the condition of being isolated from air to generate coke (or semi-coke), coal tar, crude benzene, gas and other products.

[0040] The temperature of the high-temperature waste gas is related to the operating temperature and process of the coking device or the coal carbonization device, but generally it is a high-temperature and easy-to-coke material.

[0041] In the present invention, since most of the heat is recovered during the external heat exchange process in the catalytic distillation process, the amount of ammonia water required in the subsequent steps is greatly reduced.

[0042] To illustrate the effect of the solution of the present invention, a detection method for the coking characteristics of the material is set as follows: The material and porous ceramic balls (volume ratio 3:1) are put into a high-temperature stirring kettle, and at a certain temperature and the pressure formed at this temperature, it is maintained for a certain time, and then the toluene-insoluble matter is collected. This relative amount is the coking physical property of the material. The larger the relative amount, the greater the coking tendency of the material. The collection process of the toluene-insoluble matter includes two parts. The toluene-insoluble matter in the liquid phase is measured according to GB / T 2292 - 1997; the toluene-insoluble matter on the porous ceramic balls: it is fully rinsed with toluene, and the insoluble matter in the rinsed toluene is collected to detect the weight gain of the porous ceramic balls. The sum of the above toluene-insoluble matters is the total toluene-insoluble matter.

[0043] Example 1

[0044] A catalytic distillation device for waste gas heat recovery and coal tar pretreatment (such as Figure 1 ) In it, 1 is the catalytic distillation column, 2 is the waste gas inlet, 3 is the bottom product discharge pipeline, 4 is the bottom product circulation pipeline, 5 is the gas-phase material outlet, 6 is the external heat exchanger, 11 is the gas-liquid separator, 7 is the reflux material pipeline, 8 is the external discharge pipeline of the heat-exchanged material, 9 is the device for introducing the oil-soluble suspension bed hydrogenation catalyst, 10 is the top gas discharge pipeline, and 12 is the gas-phase discharge pipeline of the gas-liquid separator.

[0045] Example 1

[0046] A catalytic distillation device for waste gas heat recovery and coal tar pretreatment (such as Figure 2),(1) is a catalytic distillation column, (2) is the raw coal gas inlet, (3) is the column bottom product discharge pipeline, (4) is the column bottom product circulation pipeline, (10) is the overhead gas discharge pipeline, (6) is an external heat exchanger, (11) is a gas-liquid separator, (7) is the reflux material pipeline, (8) is the heat-exchanged and discharged material pipeline, (9) is an oil-soluble suspension bed hydrogenation catalyst introduction device, and (12) is the gas-phase discharge pipeline of the gas-liquid separator.

[0047] Comparative Example 1

[0048] A certain coal tar processing enterprise purchases medium and low temperature coal tar externally, that is, the conventional coal tar raw material Z1 of the processing enterprise.

[0049] Example 2

[0050] The raw coal gas of a certain enterprise, with a temperature of about 600 °C, directly enters the catalytic distillation column as shown in Figure 1 . The bottom temperature of the column is controlled at 520 °C by injecting ammonia water. The mechanical impurity washing area is a spray structure. Part of the bottom material is circulated to make the liquid-gas volume ratio 100 L / cubic meter of gas (calculated based on the inlet). The catalytic distillation area is filled with packing according to 10 theoretical fractionation trays. A gas-phase collection tray is set at the position where the gas-phase temperature is about 350 °C. The temperature of the gas-phase extracted material is 350 °C. After being led out and heat-exchanged, it is recovered to a temperature of 130 °C. Part is discharged externally and part is circulated to the top of the column. The top temperature of the column is controlled at 135 °C. An oil-soluble suspension bed hydrogenation catalyst (Example 1 of CN01106013.1) is added to the top of the column. The addition amount is 1500 μg / g based on the weight of the metal element (calculated based on the sum of the mass of the liquid phase material discharged from the bottom of the catalytic distillation column and the liquid phase material discharged from the catalytic distillation area (excluding all reflux parts, that is, excluding the parts shown in 4 and 7 in the figure. This is the calculation basis in the present invention)).

[0051] The overhead exhaust gas from the catalytic distillation column is cooled to 80 °C by ammonia water spraying and then light coal tar and coal gas are recovered.

[0052] The heavy coal tar A2 discharged from the bottom of the column (after filtration), the medium coal tar B2 discharged from the catalytic distillation area, and the light coal tar C2 obtained by recovering coal tar from the overhead exhaust gas of the column. The mixed sample of the three (by production ratio) is D2.

[0053] Comparative Example 2

[0054] Referring to the reaction conditions of the method in Example 2, hydrogenation reaction is carried out with conventional coal tar Z1 as the raw material, an external hydrogen source, a hydrogen-oil volume ratio of 600:1 (under standard conditions), a temperature of 350 °C, the catalyst and its dosage are according to Example 2, and the reaction product is collected to obtain coal tar Z2.

[0055] Example 3

[0056] The coking characteristics of the coal tar obtained from the examples and comparative examples were detected. Conditions: temperature 350 °C, nitrogen pressurized to 8 MPa (gauge pressure), high-pressure stirring autoclave, time 30 minutes. The proportion of toluene-insoluble matter in the feedstock weight (relative value, with Z1 as 100%) was collected.

[0057]

Claims

1. A catalytic distillation device for heat recovery of raw coke oven gas and pretreatment of coal tar, comprising the following: (1) A catalytic distillation column; (2) The lower part of the catalytic distillation column is a washing area for mechanical impurities in raw coke oven gas, and a raw coke oven gas inlet is arranged at the lower part of the mechanical impurities washing area; (3) The upper part of the catalytic distillation column is a suspended bed catalytic distillation area, and a gas-phase material outlet is arranged in the catalytic distillation area. The gas-phase material outlet is connected to a heat exchanger through a pipeline. After the material is cooled by the heat exchanger, the material is connected to the material inlet in the middle of a gas-liquid separator through a pipeline. A gas-phase discharge port is arranged at the top of the gas-liquid separator, and a liquid-phase discharge port is arranged at the bottom of the gas-liquid separator. The liquid-phase discharge port is connected to the upper reflux port of the catalytic distillation column and an external discharge pipeline; (4) The upper reflux port of the catalytic distillation column is connected to an oil-soluble suspended bed hydrogenation catalyst addition device; The suspended bed catalytic distillation area adopts tray-type gas-liquid contact components or packing-type gas-liquid contact components; A gas-phase material outlet is arranged in the upper-middle part of the suspended bed catalytic distillation area or at the top of the catalytic distillation column.

2. The device according to claim 1, characterized in that: The catalytic distillation column is of a vertical cylindrical structure.

3. The device according to claim 1, characterized in that: The mechanical impurities washing area adopts spray-type gas-liquid contact components or tray-type gas-liquid contact components.

4. The device according to claim 1 or 3, characterized in that: An external discharge material pipeline is arranged at the bottom of the mechanical impurities washing area, and a circulation pipeline for partially circulating the discharged material back to the mechanical impurities washing area is arranged.

5. The device according to claim 4, characterized in that: A filtering device is arranged for removing mechanical impurities in the discharged material and / or circulating material.

6. The device according to claim 1, characterized in that: A gas-phase material collection device is arranged at the position of the gas-phase material outlet in the upper-middle part of the suspended bed catalytic distillation area.

7. The device according to claim 1, characterized in that: The heat exchanger is of any structure among tubular heat exchangers, spiral tubular heat exchangers, and plate heat exchangers.

8. Use of the catalytic distillation device for heat recovery of raw coke oven gas and coal tar pretreatment according to claim 1, characterized in that: The raw coke oven gas derived from a coking device or a coal carbonization device directly enters the catalytic distillation column, and while recovering heat, coal tar pretreatment and fractionation are carried out.

9. The application according to claim 8, characterized in that: The coking device or the coal carbonization device is a device that uses coal as a raw material, conducts heat treatment, produces coke, semi-coke, and by-products coal tar and gas.

10. The application according to claim 8 or 9, characterized in that: The temperature of the raw coke oven gas is 450 - 850 °C.

11. The application according to claim 10, wherein: The temperature of the raw coke oven gas is 600 - 800 °C.

12. The application according to claim 8, wherein: The operating temperature of the mechanical impurities washing area is 350 - 550 °C.

13. The application according to claim 12, characterized in that: The operating temperature of the mechanical impurities washing area is 380 - 500 °C.

14. The application according to claim 12, characterized in that: The operating temperature of the mechanical impurities washing area is 400 - 450 °C.

15. The application according to claim 12, wherein: The operating temperature is controlled by introducing ammonia water into the mechanical impurities washing area.

16. The application according to claim 8, characterized in that: The catalytic distillation column operates under normal pressure.

17. The application according to claim 8, characterized in that: Gas-phase material is led out from the catalytic distillation area of the catalytic distillation column, and the temperature of the led-out gas-phase material is 250 - 450 °C.

18. The application according to claim 17, wherein: The temperature of the led-out gas-phase material is 300 - 400 °C.

19. The application according to claim 17, characterized in that: The operating temperature at the top of the catalytic distillation column is above 110 °C.

20. The application according to claim 19, characterized in that: The operating temperature at the top of the catalytic distillation column is 110 - 250 °C.

21. The application according to claim 19, characterized in that: The operating temperature at the top of the catalytic distillation column is 120 - 150 °C.

22. The application according to claim 8, wherein: Gas-phase material is led out from the top of the catalytic distillation column, and the operating temperature at the top is 250 - 450 °C.

23. The application according to claim 22, characterized in that: The operating temperature at the top is 300 - 400 °C.

24. The application according to claim 8, wherein: The oil-soluble suspended bed hydrogenation catalyst is added to the reflux material at the top of the catalytic distillation column, and the suspended bed hydrogenation catalyst contains substances of at least one element in Group VIB and Group VIII of the periodic table.

25. The application according to claim 24, wherein: The suspended bed hydrogenation catalyst is a substance containing at least one element of cobalt, molybdenum, nickel, tungsten, and iron.

26. The application according to claim 17, characterized in that: Based on the weight of the element, the addition amount of the additive for the ebullated bed hydrotreating catalyst is 10 to 5000 μg / g.

27. The application according to claim 26, wherein: Based on the weight of the element, the addition amount of the additive for the ebullated bed hydrotreating catalyst is 50 to 3000 μg / g.

28. The application according to claim 26, wherein: Based on the weight of the element, the addition amount of the additive for the ebullated bed hydrotreating catalyst is 100 to 2000 μg / g.

29. The application according to claim 24, wherein: The oil-soluble ebullated bed hydrotreating catalyst is one or more of the organic compounds containing cobalt, molybdenum, nickel, tungsten, and iron.

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