A method and device for controlling the naphthalene content in the regeneration gas

Abstract

The present invention discloses a method and device for controlling the naphthalene content in the regeneration gas. This method alternately performs hot blowing and cold blowing on the adsorption tower using the regeneration gas, so that the naphthalene adsorbed on the adsorbent in the adsorption tower is desorbed and enters the regeneration gas, and the adsorbent is regenerated. The regeneration gas with a peak naphthalene content of 7000 - 8000 mg / Nm<supgt;3< / supgt> flowing out of the adsorption tower during the hot blowing process can effectively reduce the naphthalene content in the regeneration gas after being cooled by a cooler and the bypass regeneration gas. The regeneration gas with a high naphthalene content is sent to the end user through the gas transmission pipeline to the end user. The naphthalene content in the regeneration gas flowing out of the adsorption tower during the cold blowing process is less than 1 mg / Nm<supgt;3< / supgt>. After being heated and raised in temperature by a heater, it then enters the main gas transmission pipeline to the end user, which can resublimate the naphthalene crystallized in the pipeline during the hot blowing process. By enabling the temperature of the regeneration gas reaching the end user to be ≤50°C and the naphthalene content to be ≤530 mg / Nm<supgt;3< / supgt>, it is possible to avoid pipeline blockage caused by naphthalene crystallization in the pipeline and ensure the stable operation of the pipeline and equipment.

Description

Technical Field

[0001] The present invention belongs to the technical field of resource utilization and harmless treatment of dry naphthalene removal and regeneration gas, and specifically relates to a method and device for controlling the naphthalene content in the regeneration gas. Background Art

[0002] China has rich reserves of coal resources, and it is difficult to change the pattern of using coal as the main energy source. Coke oven gas, as a by-product of the coking process in iron and steel integrated enterprises, is produced in huge amounts every year during coking. In addition to being used for self-heating in the furnace, power generation, and chemical utilization (such as producing methanol and synthetic ammonia), the comprehensive utilization of a large amount of surplus coke oven gas has become quite urgent. The construction and commissioning of a series of projects such as coke oven gas to methanol, coke oven gas hydrogen extraction, and coke oven gas to natural gas not only conform to the national energy conservation purpose, achieve emission reduction and environmental governance, but also can generate good economic benefits.

[0003] In the technological processes of converting coke oven gas to methanol, hydrogen, natural gas, etc., the refined coke oven gas still needs to be further purified to remove impurities (such as tar, naphthalene, benzene, NH 3 etc.). These impurities are usually removed by dry methods. During the regeneration process of the adsorption tower bed layer, a large amount of impurity naphthalene will be enriched in the regeneration gas and enter the downstream. The saturated naphthalene content will continuously precipitate and crystallize on the pipeline during the cooling process. As the amount of naphthalene crystals increases, it will cause a decrease in the pipeline flow rate, and in severe cases, it will cause pipeline blockage problems. Therefore, how to control the naphthalene content in the regeneration gas is of great significance for the stable operation of downstream pipelines, equipment, and users. Especially when users have strict requirements for the quality of the regeneration gas such as temperature, naphthalene content, and stability, controlling naphthalene in long-distance pipeline transportation has become an urgent problem to be solved.

[0004] The dry naphthalene removal technology utilizes the strong adsorption of naphthalene by the naphthalene removal adsorbent at normal temperature and a certain pressure, while having a lower adsorption effect on other components, so as to achieve the purpose of removal and purification. At the same time, the adsorbent is desorbed at high temperature and low pressure to restore its adsorption capacity for reuse. Compared with traditional wet naphthalene removal and freezing naphthalene removal, it has the advantages of simple process and low cost. At present, the dry naphthalene removal technology has been widely used in industrial applications for treating low-concentration naphthalene content.

[0005] Chinese Patent Application No. 201811344746.9 discloses "an improved regeneration process for a temperature swing adsorption tower", which importantly improves the process of varying the temperature of the adsorption tower, thereby shortening the regeneration cycle and reducing energy consumption. This patent does not involve the control of the naphthalene content in the regeneration gas and the treatment of naphthalene crystallization in the pipeline.

[0006] Chinese Patent Application No. 201811080647.4 discloses "A Method and Device for Removing Impurities from Coal Gas by Temperature Swing Adsorption", which involves multi-stage adsorption for impurity treatment, increasing the length of the adsorbent bed layer to improve the separation effect. At the same time, different types of activated carbon are used to improve selectivity and extend the service life of the adsorbent. However, it does not perform relevant treatment on the regenerated gas after hot blowing and cold blowing, nor does it deal with naphthalene crystallization in the pipeline.

[0007] Since the temperature of the regenerated gas during the hot blowing process of the adsorption tower regeneration is very high, and downstream users cannot accept high-temperature gas, it is necessary to cool down the regenerated gas. However, the naphthalene content in the high-temperature regenerated gas is very high. If it is directly mixed into the downstream pipeline and mixed with cold gas, due to the temperature drop, naphthalene will crystallize, so it is impossible to simply send naphthalene into the downstream directly. Currently, dry naphthalene removal all adopts the temperature swing adsorption process, and regeneration uses high-temperature desorption. Most of the existing technologies are improvements on the regeneration process, but there are no strict requirements for the subsequent treatment and quality of the regenerated gas, so the treatment methods are relatively easy. Currently, there is no method introduction in the existing technology to control the naphthalene content in the regenerated gas flowing out of the adsorption tower to show a sinusoidal change, so that the naphthalene content in the regenerated gas is uniform and stable when it reaches the end user, and at the same time, the temperature of the regenerated gas reaching the end user is also certain. Summary of the Invention

[0008] The purpose of the present invention is to provide a method and device for controlling the naphthalene content in the regenerated gas, so that the naphthalene content in the regenerated gas is uniform and stable when it reaches the end user, that is, the naphthalene content ≤ 530 mg / Nm 3 , and the temperature ≤ 50 °C; at the same time, solve the problem of pipeline blockage caused by naphthalene crystallization in the pipeline during transportation, and ensure the stable operation of downstream pipelines and equipment.

[0009] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0010] A method for controlling the naphthalene content in the regenerated gas, comprising the following steps:

[0011] 1) The regenerated gas is heated to 140 - 160 °C by a heater and then transported to the adsorption tower. The heated regenerated gas continuously heats the adsorbent in the adsorption tower, desorbing the naphthalene on the adsorbent in the adsorption tower into the regenerated gas; the peak content of naphthalene in the regenerated gas flowing out of the regenerated gas outlet of the adsorption tower reaches 7000 - 8000 mg / Nm 3 of the regenerated gas is cooled to 88 - 110 °C by a cooler, and then enters the gas transmission main pipe to the end user. It is mixed with the normal-temperature regenerated gas from the regenerated gas bypass pipeline at the inlet of the gas transmission main pipe and then cooled to 75 - 90 °C again, while reducing the naphthalene content in the regenerated gas. Through the natural temperature drop during the transportation through the gas transmission main pipe, the temperature of the regenerated gas when it reaches the end user ≤ 50 °C, and the naphthalene content ≤ 530 mg / Nm 3 ;

[0012] 2) After the adsorption tower is desorbed in step 1), it is cold-blown with fresh regeneration gas to cool the adsorbent in the adsorption tower to 35 - 45°C. The naphthalene content in the regeneration gas flowing out from the regeneration gas outlet of the adsorption tower is less than 1 mg / Nm 3 The regeneration gas is heated to 88 - 110°C by a heater and then enters the main gas transmission pipeline to the end user. At the inlet of the main gas transmission pipeline, the regeneration gas is mixed with the regeneration gas from the regeneration gas bypass pipeline and then cooled to 75 - 90°C, causing the naphthalene crystallized in the main gas transmission pipeline in step 1) to sublime again, so that when the regeneration gas reaches the end user, the temperature ≤ 50°C and the naphthalene content ≤ 530 mg / Nm 3 ;

[0013] 3) Repeat step 1) and step 2) to completely desorb the naphthalene on the adsorbent in the adsorption tower. The naphthalene content in the regeneration gas flowing out from the adsorption tower shows a periodic sinusoidal variation between the peak content of 7000 - 8000 mg / Nm 3 and the content of less than 1 mg / Nm 3 By alternately cooling with a cooler or heating with a heater, the naphthalene content in the regeneration gas reaching the end user is ≤ 530 mg / Nm 3 , and the temperature ≤ 50°C.

[0014] Preferably, the temperature of the regeneration gas is the same after being processed by the heater and the cooler, and the temperature of the regeneration gas is controlled at 85 - 90°C in summer and 105 - 110°C in winter.

[0015] Preferably, the main gas transmission pipeline to the end user is provided with a heat-insulating layer that can control the temperature drop.

[0016] Preferably, the regeneration gas is a by-product gas from the processes of separating and extracting hydrogen from coke oven gas, natural gas, or synthesizing and extracting methanol, such as pressure swing adsorption desorbed gas, cold box tail gas, or MDEA decarbonized tail gas.

[0017] The device for the method of controlling the naphthalene content in the regeneration gas is characterized by including: an adsorption tower, which is provided with an intake pipe for connecting the regeneration gas at the upper part and a regeneration gas outlet pipe at the lower part, and a heater is provided on the regeneration gas intake pipe; a heater, which is provided with a regeneration gas outlet pipe at the upper part and a regeneration gas inlet pipe at the lower part, and the regeneration gas inlet pipe of the heater is connected to the outlet pipe of the adsorption tower; a cooler, which is provided with a regeneration gas inlet pipe at the top and a regeneration gas outlet pipe at the bottom, and the regeneration gas inlet pipe is connected to the outlet pipe of the adsorption tower; the regeneration gas outlet pipes of the heater and the cooler are connected to the main gas transmission pipeline to the end user.

[0018] Preferably, a differential pressure monitoring device is further provided, and its two measuring points are respectively located on the regeneration gas inlet pipe and the regeneration gas outlet pipe of the cooler.

[0019] Preferably, a regeneration gas bypass pipeline is further provided, and its outlet end is connected to the inlet of the gas transmission main pipe leading to the end user. A temperature control valve is provided on the regeneration gas bypass pipeline, and a temperature detection device is provided in the inlet pipeline of the gas transmission main pipe, and is electrically connected to the temperature control valve.

[0020] Preferably, two coolers are provided, one for use and one for standby.

[0021] Preferably, temperature monitoring devices are provided on the regeneration gas outlet pipeline of the heater and the regeneration gas outlet pipeline of the cooler.

[0022] Preferably, the cooler is a circulating water cooler, with a water inlet provided at the lower part and a water outlet provided at the upper part.

[0023] Preferably, the heater is a steam heater, with a steam inlet provided at the lower part and a water outlet provided at the upper part.

[0024] In a method for controlling the naphthalene content in the regeneration gas of the present invention:

[0025] The adsorption tower is alternately thermally blown and cold blown with the regeneration gas, so that the naphthalene adsorbed in the adsorption tower is completely desorbed into the regeneration gas, realizing the regeneration of the adsorption tower and enabling it to be used continuously. During the thermal blowing process, the peak content of naphthalene flowing out of the adsorption tower reaches 7000 - 8000 mg / Nm 3 of the regeneration gas is cooled by a cooler and then transported to the gas transmission main pipe of the end user. After mixing with the normal-temperature regeneration gas from the regeneration gas bypass pipeline at the inlet of the gas transmission main pipe, it is cooled again to effectively reduce the naphthalene content in the regeneration gas. Then, through the natural cooling of the gas transmission main pipe provided with a heat-insulating layer with controllable temperature drop, the naphthalene in the regeneration gas crystallizes in the gas transmission main pipe; while the naphthalene content of the regeneration gas flowing out of the adsorption tower during the cold blowing process is less than 1 mg / Nm 3 of the regeneration gas is heated by a heater and then transported to the gas transmission main pipe of the end user, with sufficient time and temperature to ensure the sublimation of the crystallized naphthalene. In this way, the thermal blowing and cold blowing processes are alternately carried out, and the naphthalene content in the regeneration gas coming out of the adsorption tower shows a periodic sinusoidal change. Through process control, the naphthalene content in the regeneration gas is quantified, so that when the regeneration gas reaches the end user, the naphthalene content in the regeneration gas is uniform and stable, that is, the naphthalene content ≤ 530 mg / Nm 3 , the temperature ≤ 50 °C, and there will be no naphthalene crystallization in the pipeline, avoiding pipeline blockage and ensuring the normal use of the pipeline.

[0026] Temperature monitoring devices are installed on the heater's regenerated gas outlet pipeline and the cooler's regenerated gas outlet pipeline. For example, if the temperature of the regenerated gas at the heater outlet is higher than the set value, the opening of the regulating valve is reduced to lower the temperature of the regenerated gas passing through the heater. If the temperature is lower than the set value, the opening of the regulating valve is increased to raise the temperature of the regenerated gas passing through the heater. If the temperature of the regenerated gas at the cooler outlet is higher than the set value, the opening of the regulating valve is increased to lower the temperature of the regenerated gas passing through the cooler. If the temperature is lower than the set value, the opening of the regulating valve is reduced to raise the temperature of the regenerated gas passing through the cooler. The temperature of the regenerated gas after passing through the heater and the cooler is the same, which is 88 - 110°C. This temperature is higher than the saturation temperature corresponding to the peak naphthalene content to avoid naphthalene crystallization in the cooler due to the too low temperature of the regenerated gas after cooling in the cooler, resulting in cooler blockage. Moreover, the regenerated gas temperature is controlled at 85 - 90°C in summer and 105 - 110°C in winter. This is because the climates in winter and summer are different, and with the same gas transmission main pipe and insulation layer thickness, the temperature drop effect is different. Therefore, different regenerated gas temperatures are required for the gas transmission main pipe entering the end user to ensure that the temperature of the regenerated gas entering the end user remains the same in winter and summer.

[0027] The device for the method of controlling the naphthalene content in the regenerated gas includes: an adsorption tower with an inlet pipeline for connecting the regenerated gas at its upper part and a regenerated gas outlet pipeline at its lower part, and a heater is installed on the regenerated gas inlet pipeline; a heater with a regenerated gas outlet pipeline at its upper part and a regenerated gas inlet pipeline at its lower part, and the regenerated gas inlet pipeline of the heater is connected to the adsorption tower outlet pipeline; a cooler with a regenerated gas inlet pipeline at the top and a regenerated gas outlet pipeline at the bottom, and the regenerated gas inlet pipeline is connected to the adsorption tower outlet pipeline; the regenerated gas outlet pipelines of the heater and the cooler are connected to the gas transmission main pipe leading to the end user.

[0028] Since the temperature of the regenerated gas is very high during the hot blow process, the peak naphthalene content in the regenerated gas can reach 7000 - 8000 mg / Nm 3 When the temperature is reduced in the cooler, it is inevitable that naphthalene will crystallize in the cooler, which will lead to cooler blockage in the long term. Therefore, two coolers are set up, one is in use and the other is in standby. If one stops running due to blockage, the other will start automatically, which does not affect the operation of the whole process. This operation is stable and has a high degree of automation, which can avoid the device from stopping running due to cooler blockage and ensure the stable operation of the device.

[0029] The regenerated gas enters the gas transmission main pipe of the end user, and is cooled again after being mixed with the normal-temperature regenerated gas from the bypass pipeline of the regenerated gas at the inlet of the gas transmission main pipe, reducing the naphthalene content in the regenerated gas, and avoiding the temperature of the regenerated gas in the cooler dropping below the saturation temperature corresponding to the peak naphthalene content, resulting in a large amount of naphthalene crystallization in the cooler and causing the cooler to be blocked. A temperature control valve is provided on the bypass pipeline of the regenerated gas, and a temperature detection device is provided in the inlet pipeline of the gas transmission main pipe, and is electrically connected to the temperature control valve. The temperature detection device detects the temperature after the regenerated gas is mixed with the normal-temperature regenerated gas from the bypass pipeline of the regenerated gas, and controls the flow rate of the regenerated gas in the bypass pipeline of the regenerated gas, so that the temperature after the regenerated gas is mixed with the normal-temperature regenerated gas from the bypass pipeline of the regenerated gas is constant, effectively reducing the naphthalene content in the regenerated gas.

[0030] At the same time, a differential pressure monitoring device is also provided, and its two measuring points are respectively located on the inlet pipeline and the outlet pipeline of the regenerated gas of the cooler. If the differential pressure of the cooler exceeds the set value of 10 kPa, the opening of the regulating valve is reduced. Since naphthalene crystallizes in the cooler, the gas pressures before and after the cooler will be different, resulting in a pressure difference. The opening of the regulating valve can be adjusted according to the pressure difference to control the temperature of the regenerated gas after passing through the cooler. And a temperature monitoring device is provided on the outlet pipeline of the regenerated gas of the cooler. If the temperature of the regenerated gas at the outlet of the cooler is higher than the set value, the opening of the regulating valve is increased to reduce the temperature of the regenerated gas passing through the cooler. If the temperature is lower than the set value, the opening of the regulating valve is reduced to increase the temperature of the regenerated gas passing through the cooler; at the same time, the temperature and the differential pressure adopt a low-select control method, and the upper limit of the outlet temperature set value is limited to 130 °C, otherwise the temperature requirement when the regenerated gas reaches the end user cannot be met.

[0031] The beneficial effects of the present invention:

[0032] The present invention uses the regenerated gas to alternately perform hot blowing and cold blowing on the adsorbent in the adsorption tower, so that the naphthalene on the adsorbent in the adsorption tower can be completely desorbed, and the adsorbent is regenerated. The hot blowing and cold blowing processes are alternately carried out, and the naphthalene content in the regenerated gas flowing out of the adsorption tower changes periodically in a sine wave. The regenerated gas flowing out of the adsorption tower is cooled by the cooler and the bypass gas, reducing the naphthalene content in the regenerated gas. Combined with heating the regenerated gas during the cold blowing process, the naphthalene content in the regenerated gas during the hot blowing and cold blowing processes is quantified, so that the naphthalene content in the regenerated gas is uniform and stable when the regenerated gas reaches the end user, that is, the naphthalene content ≤ 530 mg / Nm 3 , and the temperature ≤ 50 °C; at the same time, it solves the problem of pipeline blockage caused by naphthalene crystallization in the pipeline during the transportation process, ensuring the stable operation of the downstream pipeline and equipment.

[0033] The present invention can effectively control the crystallization of naphthalene in the pipeline during the pipeline transportation process of the regenerated gas, especially during long-distance pipeline transportation, thereby ensuring the stable operation of the downstream pipeline and equipment. The entire process flow is simple, the investment cost is low, the operation cost is low, there is no solid waste and wastewater to be treated, and the overall process is more environmentally friendly.

[0034] In the present invention, naphthalene will inevitably crystallize in the gas transmission main pipe to the end user as the temperature of the regeneration gas drops. However, during the cold blow process, the regeneration gas almost free of impurities can re-sublime the crystallized naphthalene into the regeneration gas after heating. Therefore, the process of naphthalene in the pipeline is an alternating process of "crystallization - sublimation - crystallization - sublimation", and the peak of naphthalene content is cut and stabilized in a relatively low temperature range.

[0035] In view of the clear and strict requirements of end users for the quality of the regeneration gas, such as temperature, naphthalene content and stability, the present invention can effectively solve the problem of treating naphthalene-containing gas and achieve the purpose of simplification and stabilization.

[0036] After the cooler of the present invention, it needs to be controlled at a relatively high temperature to avoid blockage of the heat exchanger caused by crystallization of naphthalene on the heat exchange tubes due to too low temperature of the regeneration gas after being cooled by the cooler. In addition, during the long-distance pipeline transportation process, the temperature drop of the pipeline is greatly affected by different climatic reasons in winter and summer. Therefore, the present invention controls the regeneration gas at different temperatures in winter and summer respectively for different working conditions.

[0037] The present invention cools the regeneration gas in the hot blow stage, and the cooler and the heater work in parallel to save more energy.

[0038] For the impurity-containing gas, especially the impurity sensitive to the saturation concentration and temperature, the method of the present invention can effectively reduce the peak concentration and achieve the goal of equalization. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic structural diagram of an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0040] See Figure 1 , the device for the method of controlling the naphthalene content in the regeneration gas according to the present invention includes:

[0041] An adsorption tower 1, with an intake port pipe connecting to the regeneration gas at its upper part and a regeneration gas outlet pipe at its lower part. A steam heater 2 is provided on the regeneration gas intake port pipe.

[0042] A heater 3 (steam heater), with a steam inlet and a regeneration gas outlet pipe at its upper part, and a condensate outlet and a regeneration gas inlet pipe at its lower part. The regeneration gas inlet pipe of the heater is connected to the outlet pipe of the adsorption tower 1.

[0043] A cooler 4 (circulating water cooler), with a cooling water inlet pipe at its lower part, a hot water outlet pipe at its upper part, a regeneration gas inlet pipe at its top and a regeneration gas outlet pipe at its bottom. The regeneration gas inlet pipe of the cooler 4 (circulating water cooler) is connected to the outlet pipe of the adsorption tower 1.

[0044] The outlet pipelines of the regeneration gas of the heater 3 (steam heater) and the cooler 4 (circulating water cooler) are connected to the gas transmission main pipeline of the end user.

[0045] Preferably, a differential pressure monitoring device is further provided, and its two measuring points are respectively located on the inlet pipeline and the outlet pipeline of the regeneration gas of the cooler 4 (circulating water cooler).

[0046] Preferably, a bypass pipeline for the regeneration gas is further provided, and its outlet end is connected to the inlet of the gas transmission main pipeline of the end user. A temperature control valve is arranged on the bypass pipeline for the regeneration gas, and a temperature detection device is arranged in the inlet pipeline of the gas transmission main pipeline and is electrically connected to the temperature control valve.

[0047] Preferably, the cooler (circulating water cooler) includes two units 4 and 4', one for use and one for standby.

[0048] Preferably, temperature monitoring devices are arranged on the outlet pipeline of the regeneration gas of the heater and the outlet pipeline of the regeneration gas of the cooler.

[0049] The temperature control valve of the steam heater is on the side of the condensate pipeline, and the temperature of the regeneration gas passing through the heater is controlled by the condensate water level, which can effectively utilize the subcooling section and reduce energy consumption.

[0050] Method steps for controlling the naphthalene content in the regeneration gas:

[0051] 1) The regeneration gas is heated to 160 °C by the heater 2 and then transported to the adsorption tower 1. The heated regeneration gas continuously heats the adsorbent in the adsorption tower, and the naphthalene adsorbed on the adsorbent in the adsorption tower is desorbed into the regeneration gas; the peak content of naphthalene flowing out from the outlet of the regeneration gas of the adsorption tower 1 reaches 7000 mg / Nm 3 The regeneration gas is cooled to 88 °C by the cooler and then enters the gas transmission main pipeline of the end user. It is mixed with the normal-temperature regeneration gas from the bypass pipeline of the regeneration gas at the inlet of the gas transmission main pipeline and then cooled to 75 °C again. After reducing the naphthalene content in the regeneration gas, it undergoes natural temperature drop through a gas transmission main pipeline with a length of 3 km. When it reaches the end user, the temperature of the regeneration gas is 50 °C, and the naphthalene content is 530 mg / Nm 3 ;

[0052] 2) After the desorption in step 1), the adsorption tower is cold-blown with new regeneration gas to cool the adsorbent in the adsorption tower to 40 °C, and the naphthalene content flowing out from the outlet of the regeneration gas of the adsorption tower is less than 1 mg / Nm 3The regeneration gas is heated to 88 °C by a heater and then enters the main gas pipeline for the end users. At the inlet of the main gas pipeline, the regeneration gas is mixed with the regeneration gas from the regeneration gas bypass pipeline and then cooled to 75 °C. The naphthalene crystallized in the main gas pipeline in step 1) is resublimated, so that the regeneration gas reaches the end users at a temperature of 50 °C and the naphthalene content is 530 mg / Nm 3 .

[0053] Steps 1) and 2) are repeated to completely desorb the naphthalene on the adsorbent in the adsorption tower, and the peak content of naphthalene flowing out of the adsorption tower reaches 7000 - 8000 mg / Nm 3 The regeneration gas and the content of naphthalene which is almost free of naphthalene and less than 1 mg / Nm 3 show a periodic sine variation. By alternately cooling with a cooler or heating with a heater, the naphthalene content in the regeneration gas is uniform and stable when the regeneration gas reaches the end users, that is, the naphthalene content ≤ 530 mg / Nm 3 , and the temperature ≤ 50 °C; at the same time, the problem of pipeline blockage caused by naphthalene crystallization in the pipeline during transportation is solved, ensuring the stable operation of the downstream pipeline and equipment.

Claims

1. A method for controlling the naphthalene content in the regeneration gas, characterized in that, it comprises the following steps: 1) The regenerated gas is heated to 140 - 160 °C by the first heater and then transported to the adsorption tower. The heated regenerated gas continuously warms the adsorbent in the adsorption tower, desorbing naphthalene on the adsorbent in the adsorption tower into the regenerated gas. The peak content of naphthalene flowing out from the regenerated gas outlet of the adsorption tower reaches 7000 - 8000 mg / Nm 3 The regenerated gas is cooled to 88 - 110 °C by the cooler and then enters the main gas transmission pipeline to the end user. It is mixed with the normal-temperature regenerated gas from the regenerated gas bypass pipeline at the inlet of the main gas transmission pipeline and then cooled to 75 - 90 °C again, while reducing the naphthalene content in the regenerated gas. Through the natural temperature drop during the transportation in the main gas transmission pipeline, the temperature of the regenerated gas when it reaches the end user is ≤50 °C, and the naphthalene content is ≤530 mg / Nm 3 ; 2) The adsorption tower after desorption in step 1) is cold-blown with fresh regeneration gas to cool the adsorbent in the adsorption tower to 35 - 45°C. The regeneration gas flowing out from the regeneration gas outlet of the adsorption tower with a naphthalene content of less than 1 mg / Nm 3 is heated to 88 - 110°C by the second heater and then enters the main gas transmission pipeline to the end user. At the inlet of the main gas transmission pipeline, the regeneration gas is mixed with the regeneration gas from the regeneration gas bypass pipeline and then cooled to 75 - 90°C to resublime the naphthalene crystallized in the main gas transmission pipeline in step 1), so that the temperature of the regeneration gas when it reaches the end user is ≤50°C and the naphthalene content is ≤530 mg / Nm 3 ; 3) Repeat steps 1) and 2) to completely desorb the naphthalene on the adsorbent in the adsorption tower, and the naphthalene content in the regenerated gas flowing out of the adsorption tower varies periodically sinusoidally between a peak content of 7000 - 8000 mg / Nm 3 and a content of less than 1 mg / Nm 3 By alternately cooling with a cooler or heating with a second heater, the naphthalene content in the regenerated gas reaching the end user is ≤ 530 mg / Nm 3 , and the temperature is ≤ 50 °C.

2. The method for controlling the naphthalene content in the regeneration gas according to claim 1, characterized in that, in step 1), the temperature of the regeneration gas after being cooled by the cooler before entering the adsorption tower for heating is the same as the temperature of the regeneration gas after being heated by the second heater before entering the adsorption tower for cold blowing in step 2), and the temperature of the regeneration gas is controlled at 85 - 90 °C in summer and 105 - 110 °C in winter.

3. The method for controlling the naphthalene content in the regeneration gas according to claim 1, characterized in that, in step 1) and step 2), the main gas transmission pipeline is provided with a heat preservation layer capable of controlling the temperature drop.

4. The method for controlling the naphthalene content in the regeneration gas according to claim 1, characterized in that, the regeneration gas is a by - product gas of the process of separating and extracting hydrogen from coke oven gas, natural gas or synthesizing and extracting methanol, including pressure swing adsorption desorbed gas, cold box tail gas or MDEA decarbonization tail gas.

5. An apparatus for the method for controlling the naphthalene content in the regeneration gas according to claim 1, characterized in that, it includes: An adsorption tower, which is provided with an intake pipeline for connecting the regeneration gas at the upper part and a regeneration gas outlet pipeline at the lower part, and a first heater is provided on the regeneration gas intake pipeline; A second heater, which is provided with a regeneration gas outlet pipeline at the upper part and a regeneration gas inlet pipeline at the lower part, and the regeneration gas inlet pipeline of the second heater is connected to the regeneration gas outlet pipeline of the adsorption tower; A cooler, which is provided with a regeneration gas inlet pipeline at the top and a regeneration gas outlet pipeline at the bottom, and the regeneration gas inlet pipeline of the cooler is connected to the regeneration gas outlet pipeline of the adsorption tower; The regeneration gas outlet pipelines of the second heater and the cooler are connected to the main gas transmission pipeline of the end - user.

6. The apparatus for the method for controlling the naphthalene content in the regeneration gas according to claim 5, characterized in that, a differential pressure monitoring device is further provided, and its two measuring points are respectively located on the regeneration gas inlet pipeline and the regeneration gas outlet pipeline of the cooler.

7. The apparatus for the method for controlling the naphthalene content in the regeneration gas according to claim 5 or 6, characterized in that, a regeneration gas bypass pipeline is further provided, its outlet end is connected to the inlet of the main gas transmission pipeline, a temperature control valve is provided on the regeneration gas bypass pipeline, and a temperature detection device is provided at the inlet of the main gas transmission pipeline and is electrically connected to the temperature control valve.

8. The apparatus for the method for controlling the naphthalene content in the regeneration gas according to claim 5 or 6, characterized in that, two coolers are included, one is in use and the other is in standby.

9. The apparatus for the method for controlling the naphthalene content in the regeneration gas according to claim 5, characterized in that, temperature monitoring devices are provided on the regeneration gas outlet pipeline of the second heater and the regeneration gas outlet pipeline of the cooler.

10. The apparatus for the method for controlling the naphthalene content in the regeneration gas according to claim 5 or 6, characterized in that, the cooler is a circulating water cooler, which is provided with a water inlet at the lower part and a water outlet at the upper part.

11. The apparatus for the method for controlling the naphthalene content in the regeneration gas according to claim 8, characterized in that, the cooler is a circulating water cooler, which is provided with a water inlet at the lower part and a water outlet at the upper part.

12. The device for the method of controlling the naphthalene content in the regeneration gas as described in claim 5, characterized in that, the first heater and the second heater are steam heaters, and a steam inlet is arranged at the upper part thereof, and a water outlet is arranged at the lower part thereof.

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