Coal gas supergravity benzene washing system

Abstract

The utility model belongs to the technical field of coal gas benzene washing, and particularly relates to a coal gas supergravity benzene washing system, which comprises a final cooling tower, a lean oil tank and a rich oil tank, and is additionally provided with a supergravity benzene washing machine, the output end of the final cooling tower is connected with the gas inlet end of the supergravity benzene washing machine, and debenzolized coal gas is output along the gas outlet end of the supergravity benzene washing machine. The output end of the lean oil tank is connected with the liquid inlet end of the supergravity benzene washing machine, and the input end of the rich oil tank is connected with the liquid outlet end of the supergravity benzene washing machine. According to the utility model, the coal gas is subjected to benzene washing by adopting the supergravity benzene washing machine, so that the mass transfer coefficient and the reaction rate are effectively improved, the benzene removal rate and the benzene removal efficiency of the coal gas are improved, meanwhile, the equipment miniaturization is realized, and the process cost is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of coal gas benzene washing, and in particular relates to a coal gas supergravity benzene washing system. Background Art

[0002] The coal gas after cold drum contains a high level of benzene, so it is necessary to wash the benzene from the coal gas before transporting it to the user end for use.

[0003] At present, benzene is usually washed by a benzene washing tower, but the gas-liquid mass transfer efficiency of the benzene washing tower is low, and the equipment is large, the investment is high, the construction period is long, and the operating energy consumption is high.

[0004] In addition, during the benzene washing process, lean oil is used to wash benzene from the coal gas in the benzene washing tower. After the lean oil absorbs benzene, rich oil is generated. The rich oil needs to be debenzened again with the help of a debenzening tower to convert it into lean oil for recycling. However, the existing debenzening tower has a limited debenzening rate for rich oil. With the repeated recycling of lean oil, the benzene content in the lean oil increases, thereby affecting the benzene washing effect of the benzene washing tower on the coal gas. Utility Model Content

[0005] In order to solve the problems existing in the above-mentioned prior art, the utility model provides a coal gas supergravity benzene washing system, which uses a supergravity benzene washing machine to wash benzene from coal gas, effectively improving the mass transfer coefficient and reaction rate, and improving the benzene removal rate and efficiency of coal gas, while achieving equipment miniaturization and reducing process costs.

[0006] The specific technical solution adopted by the utility model is:

[0007] A coal gas supergravity benzene washing system comprises a final cooling tower, a lean oil tank and a rich oil tank, and a supergravity benzene washing machine is additionally provided, wherein the output end of the final cooling tower is connected to the air inlet end of the supergravity benzene washing machine, the debenzened coal gas is output along the air outlet end of the supergravity benzene washing machine, the output end of the lean oil tank is connected to the liquid inlet end of the supergravity benzene washing machine, and the input end of the rich oil tank is connected to the liquid outlet end of the supergravity benzene washing machine.

[0008] The benzene washing system also includes a debenzene tower and a regenerator, the output end of the rich oil tank is connected to the input end of the regenerator, the output end of the regenerator is connected to the input end of the debenzene tower, and the lean oil output end of the debenzene tower is connected to the input end of the lean oil tank and the input end of the regenerator respectively by means of a lean oil pump.

[0009] A lean-rich oil heat exchanger is further provided between the rich oil tank and the lean oil tank, the rich oil tank is connected to the refrigerant input end of the lean-rich oil heat exchanger, the refrigerant output end of the lean-rich oil heat exchanger is connected to the input end of the regenerator, the output end of the lean oil pump is connected to the heat medium input end of the lean-rich oil heat exchanger, and the heat medium output end of the lean-rich oil heat exchanger is connected to the input end of the lean oil tank.

[0010] A first stage cooler and a second stage cooler are also provided between the lean oil tank and the lean-rich oil heat exchanger, the heat medium output end of the lean-rich oil heat exchanger is connected to the input end of the first stage cooler, the output end of the first stage cooler is connected to the input end of the second stage cooler, and the output end of the second stage cooler is connected to the input end of the lean oil tank.

[0011] The crude benzene output end of the debenzene tower is connected to the input end of the oil-water separator, the water output end of the oil-water separator is connected to the water drain tank, and the oil output end of the oil-water separator is connected to the crude benzene intermediate tank.

[0012] A reflux tank is also provided between the oil output end of the oil-water separator and the crude benzene intermediate tank, and the reflux tank is connected to the input end of the debenzene tower by means of a reflux pump.

[0013] The beneficial effects of the utility model are:

[0014] In the utility model, an ultra-gravity benzene washer is used to wash benzene from coal gas. The ultra-gravity benzene washer can generate a rotating ultra-gravity field through the high-speed rotation of the rotor. The rotating gravity field is a centrifugal force field that exceeds the earth's gravity field generated by the high-speed rotation. In the rotating ultra-gravity field, the sprayed washing liquid is torn into liquid film, liquid filaments and liquid droplets on the rotor surface, and the liquid film is further torn into liquid filaments, thereby increasing the contact surface area of ​​gas and liquid, effectively improving the mass transfer coefficient and reaction rate, thereby improving the benzene removal rate and efficiency of coal gas.

[0015] At the same time, the ultra-gravity benzene washing machine is small in size, about 1 / 10 of the volume of the benzene washing tower, which can realize the miniaturization of the equipment, reduce the height of the equipment, lower the energy consumption of the liquid delivery pump, and reduce the size of the equipment, and the operating energy consumption will also be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a process flow chart of the utility model. DETAILED DESCRIPTION

[0017] The utility model is further described below in conjunction with the accompanying drawings and specific embodiments: 1. Specific embodiments

[0019] Specific implementation examples Figure 1 As shown, the utility model provides a coal gas supergravity benzene washing system, including a final cooling tower, a lean oil tank and a rich oil tank, and a supergravity benzene washing machine is additionally provided, the output end of the final cooling tower is connected to the air inlet end of the supergravity benzene washing machine, the debenzened coal gas is output along the air outlet end of the supergravity benzene washing machine, the output end of the lean oil tank is connected to the liquid inlet end of the supergravity benzene washing machine, and the input end of the rich oil tank is connected to the liquid outlet end of the supergravity benzene washing machine.

[0020] At present, benzene washing is usually carried out by using a benzene washing tower, but the gas-liquid mass transfer efficiency of the benzene washing tower is low, and the equipment is huge, the investment is high, the construction period is long, and the operating energy consumption is large. Therefore, in the utility model, a supergravity benzene washing machine is used to wash benzene from coal gas. The existing benzene washing tower is affected and restricted by the earth's gravity field, and the mass transfer efficiency is low. The supergravity benzene washing machine can generate a rotating supergravity field through the high-speed rotation of the rotor. The rotating gravity field is a centrifugal force field that exceeds the earth's gravity field generated by high-speed rotation. In the rotating supergravity field, the sprayed washing liquid is torn into liquid film, liquid filaments and droplets on the rotor surface, and the liquid film is further torn into liquid filaments, which increases the contact surface area of ​​gas and liquid, effectively improves the mass transfer coefficient and reaction rate, and at the same time, the supergravity benzene washing machine is small in size, and actually uses 4 50000Nm 3 / h super gravity benzene washing machines are used in parallel. The integrated installation height is about 8m, the length is 3.5m, and the width is 3.2m, which is about 1 / 10 of the volume of the benzene washing tower. It can realize the miniaturization of equipment, reduce the height of equipment, and lower the energy consumption of liquid delivery pump. In addition, the equipment size is reduced, and the operating energy consumption will also be reduced.

[0021] When in use, the coal gas coming out of the final cooler enters the super gravity benzene washing machine from the bottom, and the lean oil in the lean oil tank is sprayed into the super gravity benzene washing machine to contact with the coal gas at high speed. The lean oil absorbs the benzene in the coal gas. The coal gas after benzene washing is sent to the next section after the oil mist droplets entrained are captured by the mist collector.

[0022] The benzene washing system also includes a debenzene tower and a regenerator. The output end of the rich oil tank is connected to the input end of the regenerator, and the output end of the regenerator is connected to the input end of the debenzene tower. The lean oil output end of the debenzene tower is connected to the input end of the lean oil tank and the input end of the regenerator respectively by means of a lean oil pump. In order to realize the recycling of lean oil, the utility model is also provided with a debenzene tower. The rich oil at the bottom of the supergravity benzene washing machine is pumped out by means of the rich oil pump and sent to the rich oil tank for standby use. The rich oil in the rich oil tank is sent to the debenzene tower by means of the next-level rich oil pump for debenzene regeneration to form lean oil. After cooling, the lean oil is sent to the lean oil tank for waiting for recycling. In addition, the debenzenization rate of the debenzenization tower for rich oil is limited. With the repeated recycling of lean oil, the benzene content in the lean oil increases. Therefore, a lean oil pump is provided to debenzene the rich oil multiple times. When in use, the valve between the lean oil pump and the lean oil tank is closed, and the valve between the lean oil pump and the regenerator is opened. At this time, the once treated lean oil after debenzenization in the debenzenization tower will flow into the regenerator with the help of the lean oil pump, and flow back to the debenzenization tower for secondary debenzenization. This cycle is repeated until the obtained lean oil meets the requirements.

[0023] A lean-rich oil heat exchanger is additionally provided between the rich oil tank and the lean oil tank, the rich oil tank is connected to the refrigerant input end of the lean-rich oil heat exchanger, the refrigerant output end of the lean-rich oil heat exchanger is connected to the input end of the regenerator, the output end of the lean oil pump is connected to the heat medium input end of the lean-rich oil heat exchanger, and the heat medium output end of the lean-rich oil heat exchanger is connected to the input end of the lean oil tank. Since the temperature of the lean oil after debenzenization is relatively high, it needs to be cooled, while the temperature of the rich oil is relatively low, and the debenzenization process of the rich oil in the debenzenization tower needs to be heated. Therefore, a lean-rich oil heat exchanger is provided, and the lean oil and the rich oil are heat exchanged by the lean-rich oil heat exchanger to reduce heat energy loss and process cost.

[0024] A first stage cooler and a second stage cooler are also arranged between the lean oil tank and the lean-rich oil heat exchanger. The heat medium output end of the lean-rich oil heat exchanger is connected to the input end of the first stage cooler, the output end of the first stage cooler is connected to the input end of the second stage cooler, and the output end of the second stage cooler is connected to the input end of the lean oil tank. The utility model adopts a two-stage lean oil cooler.

[0025] The crude benzene output end of the debenzene tower is connected to the input end of the oil-water separator, the water output end of the oil-water separator is connected to the water drain tank, and the oil output end of the oil-water separator is connected to the crude benzene intermediate tank. In order to further improve the economic benefit, the utility model also recovers the crude benzene separated from the debenzene tower. Since the crude benzene contains a small amount of water, the crude benzene and water are separated by the oil-water separator. After the water is separated, it is stored in the water drain tank and enters the blast cooling section by means of a water submersible pump. The crude benzene flows into the crude benzene intermediate tank and is stored in the oil depot by means of a product pump for standby use.

[0026] A reflux groove is also provided between the oil output end of the oil-water separator and the crude benzene intermediate tank. The reflux groove is connected to the input end of the debenzene tower by means of a reflux pump. The crude benzene after liquid removal may still contain a small amount of lean oil. Therefore, a reflux groove is provided. The reflux pump is used to reflux the crude benzene in the reflux groove back to the debenzene tower to collect the lean oil, thereby improving the purity of the crude benzene.

[0027] 2. Technical indicators

[0028] Table 1

[0029]

[0030] It can be seen from Table 1 that the oil washing circulation volume of the super gravity benzene washing machine is reduced, while the equipment height is reduced, the energy consumption of the liquid delivery pump is lower, the super gravity benzene washing machine has lower equipment resistance, and is suitable for operation under negative pressure and slightly positive pressure conditions. In addition, the equipment size is reduced, and the operating energy consumption will be reduced.

Claims

1. A coal gas supergravity benzene washing system, comprising a final cooling tower, a lean oil tank and a rich oil tank, characterized in that: A supergravity benzene washer is also provided. The output end of the final cooling tower is connected to the air inlet end of the supergravity benzene washer, the debenzened coal gas is output along the air outlet end of the supergravity benzene washer, the output end of the lean oil tank is connected to the liquid inlet end of the supergravity benzene washer, and the input end of the rich oil tank is connected to the liquid outlet end of the supergravity benzene washer.

2. A gas supergravity benzene washing system according to claim 1, characterized in that: The benzene washing system also includes a debenzene tower and a regenerator, the output end of the rich oil tank is connected to the input end of the regenerator, the output end of the regenerator is connected to the input end of the debenzene tower, and the lean oil output end of the debenzene tower is connected to the input end of the lean oil tank and the input end of the regenerator respectively by means of a lean oil pump.

3. A gas supergravity benzene washing system according to claim 2, characterized in that: A lean-rich oil heat exchanger is further provided between the rich oil tank and the lean oil tank, the rich oil tank is connected to the refrigerant input end of the lean-rich oil heat exchanger, the refrigerant output end of the lean-rich oil heat exchanger is connected to the input end of the regenerator, the output end of the lean oil pump is connected to the heat medium input end of the lean-rich oil heat exchanger, and the heat medium output end of the lean-rich oil heat exchanger is connected to the input end of the lean oil tank.

4. A gas supergravity benzene washing system according to claim 3, characterized in that: A first stage cooler and a second stage cooler are also provided between the lean oil tank and the lean-rich oil heat exchanger, the heat medium output end of the lean-rich oil heat exchanger is connected to the input end of the first stage cooler, the output end of the first stage cooler is connected to the input end of the second stage cooler, and the output end of the second stage cooler is connected to the input end of the lean oil tank.

5. A gas supergravity benzene washing system according to claim 2, characterized in that: The crude benzene output end of the debenzene tower is connected to the input end of the oil-water separator, the water output end of the oil-water separator is connected to the water drain tank, and the oil output end of the oil-water separator is connected to the crude benzene intermediate tank.

6. A gas supergravity benzene washing system according to claim 5, characterized in that: A reflux tank is also provided between the oil output end of the oil-water separator and the crude benzene intermediate tank, and the reflux tank is connected to the input end of the debenzene tower by means of a reflux pump.

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