A grading tar recovery system

Abstract

A graded tar recovery system relates to the field of tar recovery. The graded tar recovery system includes a heat exchanger and a tar adsorption and desorption integrated rotary device. The heat exchanger is provided with a baffle and a heat exchange tube. The tar is separated under the indirect cooling of the heat exchanger and the inertial separation of the baffle. The adsorption and desorption integrated rotary device includes four turntables with the same mechanism. Each turntable rotates in an adsorption zone and a desorption zone with different temperatures under the drive of a belt. The adsorbent absorbs the tar to separate the tar from the coal gas. The adsorbent that adsorbs the tar sequentially desorbs and recovers the tar with different boiling points in the desorption zone with different temperatures. The system can realize the classified recovery of tar with different boiling points without generating chemical wastewater, is green and environmentally friendly, and also improves the recovery efficiency.

Description

Technical Field

[0001] The invention relates to the field of tar recovery, and in particular to a graded tar recovery system. Background Art

[0002] Coal pyrolysis technology is to extract hydrogen-rich volatiles from coal for high-value utilization. Tar separation and collection are key processes in coal pyrolysis, which directly affect the processing and utilization of coal gas and tar. At present, the main method of collecting tar is direct spray cooling, which will lead to the generation of a large amount of coal chemical wastewater and bring serious environmental pollution. Therefore, it is necessary to increase purification facilities to treat chemical wastewater, and waste the gasification latent heat of coal gas and tar. In addition, the tar collected in this way is a mixture. Due to the complex composition of tar, tars with different boiling points have different uses and values. It is necessary to continue to cut and separate the tar according to the boiling point. The entire recycling system is complex, with many processes and low efficiency. Summary of the invention

[0003] In view of the shortcomings of the prior art, the object of the present invention is to provide a graded tar recovery system.

[0004] The technical solution adopted by the present invention is: a device for graded tar recovery, the technical key points of which are: comprising a heat exchanger and a tar adsorption and desorption integrated rotary wheel device, wherein baffles and heat exchange tubes are arranged inside the heat exchanger, the baffles are alternately fixed at the top and bottom ends of the inner wall of the heat exchanger, and a channel for high-temperature coal gas and tar to flow is formed between the baffles; the heat exchange tubes are divided into front heat exchange tubes, middle heat exchange tubes and rear heat exchange tubes along the flow direction of coal gas, and a flowing medium for heat exchange passes through the heat exchange tubes; a temperature detection device is arranged at the outlet of the heat exchanger, and tar recovery tanks are arranged between the starting baffle and the inner wall of the heat exchanger close to it, and between the end baffle and another inner wall close to it;

[0005] The tar adsorption and desorption integrated rotary wheel device is composed of four rotary discs with the same structure, each of which is connected by a belt, and a tar recovery tank is provided at the bottom of each rotary disc and at the gas outlet of each rotary disc; the rotary disc is driven by the belt to rotate in the adsorption zone, the first-level desorption zone, the second-level desorption zone and the third-level desorption zone in a clockwise direction; the heat exchanger outlet is connected to the rotary disc inlet located in the adsorption zone, the rotary disc outlet located in the adsorption zone is connected to the gas tank, the rotary disc inlet located in the first-level desorption zone is connected to the pressure fan and the outlet of the rear-end heat exchange pipe, the rotary disc outlet located in the first-level desorption zone is connected to the inlet of the rear-end heat exchange pipe, the rotary disc inlet located in the second-level desorption zone is connected to the pressure fan and the outlet of the intermediate heat exchange pipe, the rotary disc outlet located in the second-level desorption zone is connected to the inlet of the intermediate heat exchange pipe, the rotary disc inlet located in the third-level desorption zone is connected to the pressure fan and the inlet of the front-end heat exchange pipe, and the rotary disc outlet located in the third-level desorption zone is connected to the inlet of the front-end heat exchange pipe;

[0006] In the above scheme, the turntable includes a gas inlet, a gas outlet, a fixed plate with micropores, a filter and a temperature and pressure monitoring device. The filter, temperature and pressure monitoring device are respectively arranged at the gas outlet position of the turntable. A fixed plate is provided inside the turntable, and an adsorbent is deposited on the fixed plate.

[0007] In the above scheme, the fixing plate has two layers, and adsorbent is placed on each layer of the fixing plate.

[0008] In the above scheme, the size of the micropores is smaller than the particle size of the adsorbent, and the porosity is greater than 80%.

[0009] In the above scheme, the flowing medium is nitrogen.

[0010] In the above scheme, the tar and high-temperature coal gas at the outlet of the heat exchanger enter the turntable located in the adsorption area. When passing through the adsorbent, the tar is adsorbed by the adsorbent, thereby achieving separation of the coal gas and tar.

[0011] In the above scheme, after the coal gas is separated, nitrogen of different temperatures is introduced into the I-level desorption zone, the II-level desorption zone and the III-level desorption zone respectively. When the turntable located in the adsorption zone is turned to the I-level desorption zone, the inlet and outlet of the turntable are respectively switched to the nitrogen of the heat exchange tube at the rear end of the heat exchanger, the cover of the I-level tar collection tank is opened, and the tar with a boiling point of less than 100°C is precipitated and flows into the I-level tar collection tank; the turntable corresponding to the I-level desorption zone is turned to the II-level desorption zone, and the inlet and outlet of the turntable are respectively switched to the nitrogen of the middle heat exchange tube of the heat exchanger, the cover of the II-level tar collection tank is opened, and the tar with a boiling point of 100-20 The tar at 0°C precipitates and flows into the Level II tar collecting tank; the turntable corresponding to the Level II desorption zone rotates to the Level III desorption zone, and the inlet and outlet of the turntable are respectively switched to the nitrogen of the heat exchange tube at the front end of the heat exchanger. At this time, the Level III tar collecting tank is opened, and the tar with a boiling point of 200-00°C precipitates and flows into the Level III tar collecting tank, and almost all the tar absorbed by the adsorbent is precipitated; the small turntable in the Level III desorption zone rotates to the adsorption zone; the inlet and outlet of the turntable are respectively switched to the heat exchanger outlet gas and the gas tank. At this time, all tar collection tanks are closed, and the adsorbent begins to absorb tar in the gas.

[0012] The beneficial effects of the present invention are as follows: the graded tar recovery system includes a heat exchanger and a tar adsorption and desorption integrated rotary device, the heat exchanger is provided with a baffle and a heat exchange tube, and the tar is separated under the indirect cooling of the heat exchanger and the inertial separation of the baffle. The adsorption and desorption integrated rotary device includes four turntables with the same mechanism, each turntable rotates in the adsorption zone and the desorption zone of different temperatures under the drive of the belt, the adsorbent absorbs the tar, and the tar and the gas are separated, and the adsorbent adsorbing the tar realizes the desorption and recovery of tars with different boiling points in the desorption zone of different temperatures in turn. The system can realize the classified recovery of tars with different boiling points, does not generate chemical wastewater, is green and environmentally friendly, and also improves the recovery efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0014] Figure 1 This is a schematic diagram of the overall structure of a system for graded tar recovery in an embodiment of the present invention;

[0015] Figure 2 This is a schematic diagram of the structure of a turntable in an embodiment of the present invention;

[0016] The serial numbers in the figure are explained as follows: 1 heat exchanger, 2 baffle, 3 heat exchange tube, 4 tar collecting tank, 5 thermocouple, 6 rotor, 61 gas inlet, 62 gas outlet, 63 fixed plate, 64 adsorbent, 65 filter, 66 tar collecting tank, 67 temperature and pressure monitoring device, 7 adsorption zone, 8 level I desorption zone, 9 level II desorption zone, 10 level III desorption zone, 11 high temperature coal gas and tar. DETAILED DESCRIPTION

[0017] To make the above-mentioned objects, features and advantages of the present invention more obvious, the following is a brief description of the present invention in conjunction with the attached Figure 1 , Figure 2 The present invention is further described in detail with specific implementation modes.

[0018] The graded tar recovery system in this embodiment includes a heat exchanger 1 and an integrated tar adsorption and desorption wheel device. In this embodiment, baffles 2 are alternately arranged at the top and bottom of the heat exchanger 1, and a channel for high-temperature coal gas and tar to flow is formed between the staggered baffles 2. Tar recovery tanks 4 are respectively arranged at the lower part between the baffles 2 at the bottom of the heat exchanger 1, the lower part between the starting baffle and the inner wall of the heat exchanger near it, and the lower part between the end baffle and another inner wall near it. Multiple groups of heat pipes 3 are arranged in sequence along the gas flow direction in the heat exchanger 1, and the cooling medium in the heat exchange pipes 3 is nitrogen. In addition, in this embodiment, a thermocouple 5 for temperature detection is also provided at the outlet of the heat exchanger 1. After the high-temperature coal gas and tar 11 enter the heat exchanger 1, they flow in the channel formed by the baffles 2. On the one hand, the tar-containing gas changes its flow direction under the action of the baffles 2, and then the heavy tar is precipitated under the action of inertial centrifugal force. On the other hand, the high-temperature gas exchanges heat with the cooling medium (N2) in the heat exchange tube 3, and the temperature is reduced, so that the heavy tar with a high boiling point is precipitated. The outlet temperature of the heat exchanger 1 is maintained at about 300°C.

[0019] The tar adsorption and desorption integrated rotary device in this embodiment is composed of four sector-shaped turntables 6, each of which has the same structure and is connected to each other by a belt. The turntable 6 in this embodiment is provided with a gas inlet 61, a gas outlet 62 and two layers of fixed plates 63 with micropores, the size of which should be smaller than the adsorbent particle size, and the porosity should be more than 80%. The adsorbent 64 is piled on the fixed plate 63. A filter 65 that allows small gas molecules to pass through but large molecular tar cannot pass through is installed at the gas outlet 62 of the turntable 6, and the filter 65 has heating and backwashing functions. A temperature and pressure monitoring device 67 is also provided at the gas outlet 62 of the turntable 6. The temperature and pressure monitoring device 67 of this embodiment uses a thermocouple and a pressure sensor to monitor the temperature and pressure of the sector-shaped turntable 6. Tar collection tanks 66 are respectively provided at the gas outlet 62 and the bottom of the sector-shaped turntable 6. The tar collection tank includes three small tanks, which are used to store the tar obtained from the three desorption zones. When the sector-shaped turntable 6 turns to the adsorption zone, the three small slot covers are all closed. When it turns to the desorption zone, the small slot cover corresponding to this temperature is opened, and the other two small slot covers are closed.

[0020] The rotating wheel 6 rotates continuously in each zone under the action of the belt. Each rotating wheel 6 sequentially experiences the adsorption zone, the I-level desorption zone (the temperature is maintained at about 100°C), the II-level desorption zone (the temperature is maintained at about 200°C) and the tertiary desorption zone (the temperature is maintained at about 300°C).

[0021] The turntable 6 at the entrance of the adsorption zone is connected to the outlet of the heat exchanger 1, and the outlet of the turntable 6 at the adsorption zone is connected to the gas tank. The turntable inlet at the I-level desorption zone 8 is connected to the outlet of the pressurized fan and the heat exchange tube at the rear end (along the gas flow direction) of the heat exchanger 1 (the N2 temperature in the heat exchange tube is lower) through a pipeline, and the turntable outlet at the I-level desorption zone 8 is connected to the inlet of the heat exchange tube at the rear end of the heat exchanger 1 through a pipeline. The turntable inlet at the II-level desorption zone 9 is connected to the pressurized fan and the outlet of the middle heat exchange tube of the heat exchanger 1 through a pipeline, and the turntable outlet at the II-level desorption zone 9 is connected to the inlet of the middle heat exchange tube of the heat exchanger 1 through a pipeline. The turntable inlet at the III-level desorption zone 10 is connected to the inlet of the pressurized fan and the front end heat exchange tube of the heat exchanger 1 ((the N2 temperature in the heat exchange tube is lower)) through a pipeline, and the turntable outlet at the III-level desorption zone 10 is connected to the inlet of the front end heat exchange tube of the heat exchanger 1 through a pipeline. The front end heat exchange tube, the middle heat exchange tube and the rear end heat exchange tube in this embodiment are determined according to the type of the heat exchanger.

[0022] In this embodiment, the tar and high-temperature coal gas at the outlet of the heat exchanger 1 enter the adsorption zone 7. When passing through the adsorbent 64, the tar is adsorbed by the adsorbent, and the separation of coal gas and tar is achieved. At this time, low-temperature, medium-temperature and high-temperature nitrogen are introduced into the I, II and III desorption zones respectively, so that the temperatures of the three are maintained at about 100°C, 200°C and 300°C respectively.

[0023] After each adsorption-desorption is completed, the fan-shaped turntable corresponding to the adsorption zone 7 is transferred to the level I desorption zone 8, the turntable corresponding to the level I desorption zone 8 is transferred to the level II desorption zone 9, the turntable corresponding to the level II desorption zone 9 is transferred to the level III desorption zone 10, and the turntable of the level III desorption zone 10 is transferred to the adsorption zone 7.

[0024] When the fan-shaped turntable corresponding to the adsorption zone 7 is turned to the I-level desorption zone 8, the gas inlet and gas outlet of the turntable are respectively switched to the nitrogen of the rear end heat exchange tube of the heat exchanger 1, the cover of the I-level tar collection tank is opened, and the tar with a boiling point below 100°C is precipitated and flows into the I-level tar collection tank; the turntable corresponding to the I-level desorption zone 8 is turned to the II-level desorption zone 9, the gas inlet and gas outlet of the turntable are respectively switched to the nitrogen of the middle heat exchange tube of the heat exchanger 1, the cover of the II-level tar collection tank is opened, and the tar with a boiling point of 100-200°C is precipitated and flows into the II-level tar collection tank; II-level desorption The turntable corresponding to zone 9 rotates to the level III desorption zone 10, and the gas inlet and gas outlet of the turntable are respectively switched to the nitrogen of the heat exchange tube at the front end of the heat exchanger 1. At this time, the level III tar collection tank is opened, and the tar with a boiling point of 200-300°C precipitates and flows into the level III tar collection tank, and almost all the tar absorbed by the adsorbent is precipitated; the turntable of the level III desorption zone 10 rotates to the adsorption zone, and the gas inlet and gas outlet of the turntable are respectively switched to the gas at the outlet of the heat exchanger 1 and the gas tank. At this time, all the tar collection tanks 66 are closed, and the adsorbent 64 begins to absorb tar in the coal gas.

[0025] The above steps are repeated in a cycle. When the increase in the turntable outlet pressure exceeds 50 KPa, the filter 65 automatically starts the heating and back-blowing mode to clean the dust and tar on the filter.

[0026] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A tar recovery device, characterized in that: It comprises a heat exchanger and a tar adsorption and desorption integrated rotary wheel device, wherein baffles and heat exchange tubes are arranged inside the heat exchanger, the baffles are alternately fixed at the top and bottom of the inner wall of the heat exchanger, and a channel for high-temperature coal gas and tar to flow is formed between the baffles; the heat exchange tubes are divided into front heat exchange tubes, middle heat exchange tubes and rear heat exchange tubes along the flow direction of coal gas, and a flowing medium for heat exchange passes through the heat exchange tubes; a temperature detection device is arranged at the outlet of the heat exchanger, and tar recovery tanks are respectively arranged between the baffles at the bottom of the heat exchanger, between the starting baffle and the inner wall of the heat exchanger close to it, and between the end baffle and another inner wall close to it; The tar adsorption and desorption integrated rotary device is composed of four rotary discs with the same structure, each rotary disc is connected by a belt, and a tar recovery tank is provided at the bottom of each rotary disc and at the gas outlet of each rotary disc; the rotary disc is driven by the belt to rotate in the adsorption zone, the I-level desorption zone, the II-level desorption zone and the III-level desorption zone in a clockwise direction; The heat exchanger outlet is connected to the turntable inlet located in the adsorption zone, the turntable outlet located in the adsorption zone is connected to the gas tank, the turntable inlet located in the I-level desorption zone is connected to the pressurized fan and the rear-end heat exchange pipe outlet, the turntable outlet located in the I-level desorption zone is connected to the rear-end heat exchange pipe inlet, the turntable inlet located in the II-level desorption zone is connected to the pressurized fan and the middle heat exchange pipe outlet, the turntable outlet located in the II-level desorption zone is connected to the middle heat exchange pipe inlet, the turntable inlet located in the III-level desorption zone is connected to the pressurized fan and the front-end heat exchange pipe inlet, and the turntable outlet located in the III-level desorption zone is connected to the front-end heat exchange pipe inlet.

2. The tar recovery device according to claim 1, characterized in that: The turntable includes a gas inlet, a gas outlet, a fixed plate with micropores, a filter, and a temperature and pressure monitoring device. The filter, temperature and pressure monitoring device are respectively arranged at the gas outlet position of the turntable. A fixed plate is provided inside the turntable, and an adsorbent is deposited on the fixed plate.

3. The tar recovery device according to claim 2, characterized in that: The fixing plate has two layers, and adsorbent is placed on each layer of the fixing plate.

4. The tar recovery device according to claim 2, characterized in that: The micropore size is smaller than the adsorbent particle size, and the porosity is greater than 80%.

5. The tar recovery device according to claim 1, characterized in that: The flowing medium is nitrogen.

6. The tar recovery device according to claim 1, characterized in that: The tar and high-temperature coal gas at the outlet of the heat exchanger enter the gas inlet of the turntable located in the adsorption zone. When passing through the adsorbent, the tar is adsorbed by the adsorbent, thereby achieving separation of the coal gas and tar.

7. The tar recovery device according to claim 6, characterized in that: After the coal gas is separated, nitrogen of different temperatures is introduced into the I desorption zone, the II desorption zone and the III desorption zone respectively. When the turntable in the adsorption zone is turned to the I desorption zone, the inlet and outlet of the turntable are respectively switched to the nitrogen of the heat exchange tube at the rear end of the heat exchanger, the cover of the I tar collection tank is opened, and the tar with a boiling point below 100°C is precipitated and flows into the I tar collection tank; the turntable corresponding to the I desorption zone is turned to the II desorption zone, the inlet and outlet of the turntable are respectively switched to the nitrogen of the middle heat exchange tube of the heat exchanger, the cover of the II tar collection tank is opened, and the tar with a boiling point of 100-200°C is precipitated. The oil precipitates and flows into the Level II tar collection tank; the turntable corresponding to the Level II desorption zone rotates to the Level III desorption zone, and the inlet and outlet of the turntable are switched to the nitrogen of the heat exchange tube at the front end of the heat exchanger. At this time, the Level III tar collection tank is opened, and the tar with a boiling point of 200-300°C precipitates and flows into the Level III tar collection tank, and almost all the tar absorbed by the adsorbent is precipitated; the small turntable in the Level III desorption zone rotates to the adsorption zone; the inlet and outlet of the turntable are switched to the heat exchanger outlet gas and the gas tank respectively. At this time, all tar collection tanks are closed, and the adsorbent begins to absorb tar in the gas.

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