Pressure swing adsorption system

Abstract

The utility model discloses a pressure swing adsorption system. The system comprises a pretreatment unit, an adsorption and desorption device and an emptying unit which are connected in sequence, the adsorption and desorption device is also connected with a condensation circulation pipeline, a heating circulation pipeline and a first desorption pipeline; the adsorption and desorption device comprises at least three adsorption columns which are connected in parallel and are all connected with the pretreatment unit, the emptying unit, the condensation circulating pipeline, the heating circulating pipeline and the desorption pipeline through valve pipelines. According to the invention, multi-stage cyclic adsorption and desorption are adopted, and heat generated in the adsorption process is converted into a heat source in the desorption process by using the heat storage adsorption material, so that rapid temperature exchange is realized, and meanwhile, only normal-pressure adsorption is needed.

Description

Technical Field

[0001] The present application relates to the technical field of industrial waste gas treatment, and more specifically, to a pressure swing adsorption system. Background Art

[0002] Pressure Swing Adsorption (PSA) is an efficient physical adsorption separation technology that realizes selective adsorption and regeneration of adsorbents by periodically changing the system pressure. This technology has a wide range of applications in the field of gas separation and purification, especially in many fields such as chemical production, healthcare, food packaging, electronics production, and product painting. With the progress of technology and the change of market demand, the pressure swing adsorption technology is developing towards a more efficient, more environmentally friendly, and more intelligent direction. Researchers are committed to developing new high-performance adsorbents, reducing energy consumption and waste gas emissions by optimizing the process flow and equipment design, and realizing green production.

[0003] Currently, the conventional pressure swing adsorption process in the market for treating low-concentration waste gas aims to meet the waste gas emission standards. It adopts the operation mode of high-pressure adsorption and vacuum desorption. The adsorption process requires a pressure boost operation, with a complex process route and high investment costs. At the same time, in the conventional pressure swing adsorption process, heat is released during adsorption and absorbed during desorption. To effectively utilize the heat conversion under operating conditions, a large heat exchanger is additionally added to meet the process requirements. However, the heat exchanger has a large specification, and it is difficult to realize industrial application. Moreover, the complex process flow significantly increases the investment cost, operating cost, and floor area of the process device. Especially for the treatment of medium- and high-concentration industrial waste gas, there is still no good solution.

[0004] In view of this, the present application is specifically proposed. Summary of the Utility Model

[0005] The purpose of the present application is to provide a pressure swing adsorption system that realizes rapid temperature exchange by adopting multi-stage cyclic adsorption and desorption and using a heat storage adsorption material to convert the heat generated during the adsorption process into the heat source for the desorption process, and only requires atmospheric pressure adsorption.

[0006] The present application provides a pressure swing adsorption system, including:

[0007] A pretreatment unit, an adsorption and desorption device, and an evacuation unit connected in sequence; the adsorption and desorption device is also respectively connected with a condensation circulation pipeline, a heating circulation pipeline, and a first desorption pipeline;

[0008] The adsorption and desorption device includes at least three adsorption columns connected in parallel, and each adsorption column is connected to the pretreatment unit, the evacuation unit, the condensation circulation pipeline, the heating circulation pipeline, and the desorption pipeline through valve pipelines.

[0009] Preferably, the adsorption column includes a heat storage material or a heat storage adsorption material.

[0010] More preferably, the heat storage adsorption material includes a mixture or reaction product of an adsorption material and a heat storage material precursor.

[0011] Further preferably, the heat storage material precursor includes one or more of SiC, SiO2, Al2O3 or TiO2.

[0012] Preferably, the ash content of the heat storage adsorption material is 25-80%.

[0013] Further, the pretreatment unit includes a temperature and humidity adjustment device, a filter and a primary adsorption fan connected in sequence. The adsorption column is provided with an adsorption gas inlet, and the downstream of the primary adsorption fan is connected to the adsorption gas inlet.

[0014] Further, the adsorption column is also provided with an adsorption gas outlet. The upstream of the condensation circulation pipeline is connected to the adsorption gas outlet, and the downstream is connected to the adsorption gas inlet; an adsorption condenser and a secondary adsorption fan are sequentially arranged on the condensation circulation pipeline.

[0015] Further, the adsorption column is also provided with a heating gas outlet and a heating gas inlet. The upstream of the heating circulation pipeline is connected to the heating gas outlet, and the downstream is connected to the heating gas inlet; a heating device and a heating fan are sequentially arranged on the heating circulation pipeline.

[0016] Further, the adsorption column is also provided with a first desorption gas outlet. The upstream of the first desorption pipeline is connected to the first desorption gas outlet, and a first vacuum pump, a condensation device and a stratified solvent tank are sequentially arranged downstream.

[0017] Preferably, the system is also provided with a second desorption gas outlet and a second desorption pipeline. The upstream of the second desorption pipeline is connected to the second desorption gas outlet, and a second vacuum pump is arranged downstream and is connected to the condensation device and the stratified solvent tank through the second vacuum pump.

[0018] Preferably, the condensation device includes a primary condenser and a secondary condenser.

[0019] Preferably, the pressure swing adsorption system further includes a nitrogen inlet and a displacement gas outlet pipeline; the nitrogen inlet is arranged on the pipeline between the heating device and the heating fan; the upstream of the displacement gas outlet pipeline is connected to the pipeline upstream of the heating device, and the downstream is connected to the upstream of the primary adsorption fan.

[0020] More preferably, an oxygen concentration detector for selecting one of two is arranged on the displacement gas outlet pipeline.

[0021] The present application also provides a pressure swing adsorption method based on the pressure swing adsorption system described above:

[0022] After the waste gas is treated by the pretreatment unit, it enters one of the at least three adsorption columns for atmospheric pressure primary adsorption;

[0023] The primary adsorption waste gas is cooled by the condensation circulation pipeline and then enters another adsorption column for atmospheric pressure secondary adsorption, and then is evacuated through the evacuation unit;

[0024] Start the heating circulation pipeline and the desorption pipeline, and preheat and / or vacuum desorb the saturated adsorption column successively.

[0025] Further, the temperature and humidity adjustment device of the pretreatment unit adjusts the temperature of the incoming waste gas to 20-30 °C; the filter is used to remove particulate matter in the waste gas.

[0026] According to the components, concentration and air volume of the waste gas inlet, and while maintaining a continuous operation condition, multiple adsorption columns can be set.

[0027] As an alternative technical solution, when there are three adsorption columns, cyclic alternating operation is performed, in which at least one adsorption column performs primary adsorption, at least one adsorption column performs secondary adsorption, and at least one adsorption column performs preheating and vacuum desorption.

[0028] As an alternative technical solution, when there are four or more adsorption columns, cyclic alternating operation is performed, in which at least one adsorption column performs primary adsorption, at least one adsorption column performs secondary adsorption, at least one adsorption column performs preheating, and at least one adsorption column performs vacuum desorption.

[0029] As an alternative technical solution, when there are five or more adsorption columns, cyclic alternating operation is performed, in which at least one adsorption column performs primary adsorption, at least one adsorption column performs secondary adsorption, at least one adsorption column performs preheating, at least one adsorption column performs primary vacuum desorption, and at least one adsorption column performs secondary vacuum desorption.

[0030] Preferably, before starting the heating circulation pipeline and the desorption pipeline, the system is replaced and protected with nitrogen.

[0031] More preferably, the replaced gas is returned to the adsorption and desorption device for adsorption treatment.

[0032] Preferably, the adsorption column includes a heat storage material or a heat storage adsorption material; the heat storage material or the heat storage adsorption material stores heat during the adsorption process and releases heat during the desorption process to ensure that the design requirements are met during the adsorption time.

[0033] This application is for a concentration range of 10 g / m3 ~1000 g / m 3 to treat medium- and high-concentration waste gas from different industries, with better effects.

[0034] Furthermore, an on-line monitoring system is set at the adsorption outlet of the primary adsorption (i.e., the adsorption gas outlet of each adsorption column) to monitor the tail gas emission concentration in real time. When the emission concentration reaches the design target or the adsorption time of the adsorption column reaches the design time, the adsorption column switches to the preheating vacuum desorption stage. The adsorption process of this application adopts a secondary adsorption process, and the waste gas emission standard can be met through one round of secondary adsorption process without multiple cyclic adsorption operations, ensuring high purification efficiency and significantly reducing the operation cost.

[0035] When nitrogen purging and replacement are required, the two-in-one oxygen concentration detector monitors the oxygen concentration in the system. When the oxygen concentration < 5%, after reaching the target safety value, the nitrogen protection is turned off. Then it switches to the preheating mode, starts the heating device for cyclic heating, and stops heating when the temperature of the gas heated in the heating circulation pipeline rises to 60 - 80°C, and then switches to the vacuum desorption mode.

[0036] Turn on the first vacuum pump or the second vacuum pump to conduct vacuum desorption and regeneration on the adsorption material. The waste gas at the desorption outlet contains a large amount of VOCs and a small amount of moisture. It can first be condensed by a primary condenser, with circulating water condensation and a condensation temperature of 40 - 50°C, and then enter the secondary condenser for secondary condensation, with a condensation temperature of 5 - 10°C. The condensate produced after condensation enters the separation tank for separation and temporary storage.

[0037] In this application, cyclic switching operations are performed among several adsorption columns. At least two adsorption columns are respectively performing primary and secondary adsorption operations, and at least one adsorption column is performing preheating and / or desorption regeneration operations. Each adsorption column operates alternately and continuously according to the set time sequence steps. When the adsorption column performing primary adsorption reaches adsorption saturation and switches to vacuum desorption, the adsorption column serving as secondary adsorption switches to primary adsorption and is connected in series with the next adsorption column for secondary adsorption. The cyclic switching operation of the system adsorption columns meets the continuous operation of the process of atmospheric pressure adsorption - vacuum desorption, greatly shortening the overall operation time and improving the process operation efficiency.

[0038] Compared with the prior art, this application has the following beneficial effects:

[0039] In this application, multiple parallel adsorption and desorption devices are organically connected to the condensation circulation pipeline, the heating circulation pipeline, and the desorption pipeline, realizing continuous adsorption, preheating, and desorption regeneration treatment of waste gas, and significantly improving the overall process operation cycle. At the same time, special heat storage materials are used in the adsorption and desorption devices, which have both high-performance adsorbent properties and heat storage efficiency, realizing the atmospheric pressure adsorption and vacuum desorption processes. No additional boosting equipment is required during the adsorption process, the process route is simple, and the operation difficulty and design cost are reduced.

[0040] It should be emphasized that the regenerative adsorption material of this application exhibits high-efficiency heat storage performance while maintaining a high capacity during the adsorption process. This adsorption material can effectively convert the heat generated during the adsorption process into the heat source for the desorption process, thereby achieving rapid temperature exchange, enabling the system's heat utilization rate to exceed 90%, significantly reducing the overall process energy consumption, and saving at least 80% of the energy consumption.

[0041] This application can also reasonably configure multiple adsorption and desorption device combinations according to the different components and concentrations of the waste gas to be treated to adapt to different working conditions and ensure high purification efficiency and treatment capacity.

[0042] Through the following detailed description of the exemplary embodiments of this application with reference to the accompanying drawings, other features and advantages of this application will become clear. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The drawings incorporated in and constituting a part of this specification illustrate embodiments of this application and, together with the description, are used to explain the principles of this application.

[0044] Figure 1 It is a schematic diagram of the system structure of Embodiment 1 of this application;

[0045] Figure 2 It is a schematic diagram of the system structure of Embodiment 2 of this application;

[0046] Figure 3 It is a schematic diagram of the system structure of Embodiment 3 of this application.

[0047] DESCRIPTION OF THE REFERENCE NUMERALS:

[0048] P1 - Workshop waste gas; P2 - Waste gas at the outlet of the first-stage adsorption; P3 - Waste gas at the outlet of condensation; P4 - Exhaust unit; P5 - Waste gas at the outlet of heating; P6 - Waste gas at the outlet of the first desorption; P7 - Nitrogen inlet; P8 - Displacement gas outlet pipeline; P9 - Waste gas at the outlet of the second desorption; T1 to T5 - Adsorption columns.

[0049] 1 - Temperature and humidity adjustment device; 2 - Filter; 3 - Primary adsorption fan; 4 - Adsorption condenser; 5 - Secondary adsorption fan; 6 - Heater; 7 - Heating fan; 8 - First vacuum pump; 9 - Primary condenser; 10 - Secondary condenser; 11 - Stratified solvent tank; 12 - Oxygen concentration detector; 13 - Second vacuum pump. Detailed implementation manners

[0050] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that: unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present application.

[0051] The following description of at least one exemplary embodiment is merely illustrative in nature and in no way serves as a limitation to the present application, its application, or its use.

[0052] Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and devices should be regarded as part of the specification.

[0053] In all the examples shown and discussed herein, any specific value should be construed as merely exemplary and not as a limitation. Accordingly, other examples of the exemplary embodiments may have different values.

[0054] It should be noted that: like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0055] Embodiment 1

[0056] Refer to Figure 1 , a pressure swing adsorption system, comprising a pretreatment unit, an adsorption and desorption device, and an evacuation unit P4 connected in sequence; the adsorption and desorption device is also respectively connected with a condensation circulation pipeline, a heating circulation pipeline, and a first desorption pipeline.

[0057] The adsorption and desorption device is four adsorption columns T1 - T4 connected in parallel, and each of the adsorption columns is connected to the pretreatment unit, the evacuation unit P4, the condensation circulation pipeline, the heating circulation pipeline, and the desorption pipeline through valve pipelines.

[0058] The adsorption columns T1 - T4 include heat storage materials, specifically a mixture of activated carbon and SiC, with an ash content of 25%.

[0059] The pretreatment unit includes a temperature and humidity adjustment device 1, a filter 2, and a primary adsorption fan 3 connected in sequence. The adsorption columns T1 - T4 are each provided with an adsorption gas inlet, and the downstream of the primary adsorption fan 3 is connected to the adsorption gas inlet.

[0060] The adsorption columns T1 to T4 are also provided with adsorption gas outlets, the upstream of the condensation circulation pipeline is connected to the adsorption gas outlets, and the downstream is connected to the adsorption gas inlets; an adsorption condenser 4 and a secondary adsorption fan 5 are sequentially connected on the condensation circulation pipeline.

[0061] The adsorption columns T1 to T4 are also provided with heating gas outlets and heating gas inlets. The upstream of the heating circulation pipeline is connected to the heating gas outlets, and the downstream is connected to the heating gas inlets; a heater 6 and a heating fan 7 are sequentially connected on the heating circulation pipeline.

[0062] The adsorption columns T1 to T4 are also provided with first desorption gas outlets. The upstream of the first desorption pipeline is connected to the first desorption gas outlets, and a first vacuum pump 8, a primary condenser 9, a secondary condenser 10 and a stratified solvent tank 11 are sequentially arranged downstream.

[0063] A pressure swing adsorption method based on the pressure swing adsorption system described above:

[0064] The waste gas from a certain lithium battery separator production process has an exhaust air volume of 10000 Nm 3 / h air volume, the main component is dichloromethane, the total concentration of the waste gas is 500 g / m 3 , the exhaust gas discharge temperature is 50 °C, the relative humidity is 30%, and it is required that the exhaust gas discharge concentration after treatment < 20 mg / m 3 .

[0065] The workshop waste gas P1 enters the temperature and humidity adjustment device 1, the temperature drops to 20 °C, and enters the filter 2 to remove the particulate matter in the waste gas. The adsorption columns T1 to T4 are all filled with heat storage adsorption materials, and are introduced into the adsorption column T1 by the primary adsorption fan 3 for atmospheric pressure primary adsorption. The concentration of the waste gas P2 at the primary adsorption outlet is 1 - 40 g / m 3 , and the outlet temperature is 60 °C. To ensure the purification efficiency of the adsorption process and ensure that the outlet concentration meets the emission requirements, the waste gas P2 at the primary adsorption outlet enters the adsorption condenser 4 for cooling to obtain the condensed outlet waste gas P3, the temperature is adjusted to 25 °C, and then is introduced into the adsorption column T2 by the secondary adsorption fan 5 for atmospheric pressure secondary adsorption. After adsorption by the adsorption column T2, the emission concentration of the waste gas < 20 mg / m 3 , and is discharged through the evacuation unit P4.

[0066] When the adsorption column T1 for primary adsorption reaches adsorption saturation, it is switched to the vacuum desorption mode, and the first vacuum pump 8 is turned on to perform vacuum desorption regeneration on the adsorption material. Since there is heat storage material in the adsorption column, the system hardly needs to supplement extra heat. The exhaust gas P6 at the first desorption outlet contains a large amount of VOCs and a small amount of moisture. First, it is condensed by the primary condenser 9 with circulating water for condensation at a temperature of 40°C, and then enters the secondary condenser 10 for secondary condensation at a temperature of 10°C. The condensate produced after condensation enters the stratified solvent tank 11 for stratification and temporary storage.

[0067] In this process, cyclic switching operations are set among four adsorption columns, or cyclic switching operations can also be set among three of them. Two of the adsorption columns are respectively used for primary and secondary adsorption operations, one is used for vacuum desorption regeneration operation, or two are respectively used for preheating and vacuum desorption regeneration operations. Each adsorption column operates alternately and continuously according to the set time sequence steps to meet the continuous operation of the process of atmospheric pressure adsorption - vacuum desorption.

[0068] In other embodiments, three adsorption columns can also be directly set. Two of the adsorption columns are respectively used for primary and secondary adsorption operations, and one is used for vacuum desorption regeneration operation.

[0069] In this embodiment, an on - line monitoring system can be set at the adsorption gas outlet of each adsorption column to monitor the tail gas emission concentration in real time. When the emission concentration reaches the design target or the adsorption time of the adsorption column reaches the design time, the adsorption column is switched to the preheating and / or vacuum desorption stage.

[0070] Embodiment 2

[0071] See Figure 2 , a pressure swing adsorption system, including a pretreatment unit, an adsorption - desorption device, and an evacuation unit P4 connected in sequence; the adsorption - desorption device is also respectively connected with a condensation circulation pipeline, a heating circulation pipeline, and a first desorption pipeline.

[0072] The adsorption - desorption device includes four adsorption columns T1 - T4 connected in parallel. Each adsorption column is connected to the pretreatment unit, the evacuation unit P4, the condensation circulation pipeline, the heating circulation pipeline, and the desorption pipeline through valve pipelines.

[0073] The adsorption columns T1 - T4 include heat storage material, specifically the reaction product of activated carbon and SiC with an ash content of 65%. In other embodiments of this example, it can also be a mixture of activated carbon and SiC with an ash content of 25%.

[0074] The pretreatment unit includes a temperature and humidity adjustment device 1, a filter 2, and a primary adsorption fan 3 connected in sequence. The adsorption columns T1 - T4 are provided with adsorption gas inlets, and the downstream of the primary adsorption fan 3 is connected to the adsorption gas inlets.

[0075] The adsorption columns T1 to T4 are also provided with adsorption gas outlets. The upstream of the condensation circulation pipeline is connected to the adsorption gas outlets, and the downstream is connected to the adsorption gas inlets; an adsorption condenser 4 and a secondary adsorption fan 5 are sequentially arranged on the condensation circulation pipeline.

[0076] The adsorption columns T1 to T4 are also provided with heating gas outlets and heating gas inlets. The upstream of the heating circulation pipeline is connected to the heating gas outlets, and the downstream is connected to the heating gas inlets; a heater 6 and a heating fan 7 are sequentially arranged on the heating circulation pipeline.

[0077] The adsorption columns T1 to T4 are also provided with first desorption gas outlets. The upstream of the first desorption pipeline is connected to the first desorption gas outlets, and a first vacuum pump 8, a primary condenser 9, a secondary condenser 10 and a stratified solvent tank 11 are sequentially arranged downstream.

[0078] The pressure swing adsorption system further includes a nitrogen inlet P7 and a displacement gas outlet pipeline P8; the nitrogen inlet P7 is arranged on the pipeline between the heater 6 and the heating fan 7; the upstream of the displacement gas outlet pipeline P8 is connected to the pipeline upstream of the heater 6, and the downstream is connected to the pipeline upstream of the primary adsorption fan 3. An oxygen concentration detector 12 is provided on the displacement gas outlet pipeline P8 for selection.

[0079] A pressure swing adsorption method based on the pressure swing adsorption system described above:

[0080] The exhaust gas from the reaction kettle and the vacuum pump in a fine chemical industry has an exhaust air volume of 1000 Nm 3 / h, the components are methanol waste gas, the total concentration of the waste gas is 100 g / m 3 , the exhaust gas discharge temperature is 40 °C, and the relative humidity is 30%. It is required that the exhaust gas discharge concentration after treatment < 20 mg / m 3 .

[0081] The workshop waste gas P1 enters the temperature and humidity adjustment device 1, the temperature is reduced to 20 °C, and then enters the filter 2 to remove the particulate matter in the waste gas. The adsorption columns T1 to T4 are filled with heat storage adsorption materials. The waste gas is introduced into the adsorption column T1 by the primary adsorption fan 3 for atmospheric pressure primary adsorption. The concentration of the waste gas at the primary adsorption outlet P2 is 1 - 20 g / m 3 , and the outlet temperature is 55 °C. To ensure the purification efficiency of the adsorption process and ensure that the outlet concentration meets the emission requirements, the waste gas at the primary adsorption outlet P2 enters the adsorption condenser 4 for cooling to obtain the condensed outlet waste gas P3, the temperature is adjusted to 25 °C, and then is introduced into the adsorption column T2 by the secondary adsorption fan 5 for atmospheric pressure secondary adsorption. After adsorption by the adsorption column T2, the emission concentration of the waste gas < 20 mg / m 3 , and is discharged through the evacuation unit P4.

[0082] Due to the flammable and explosive problems of methanol waste gas, the system needs to be protected by nitrogen filling before the preheating vacuum desorption operation. Therefore, when the adsorption column T1 for primary adsorption reaches adsorption saturation, nitrogen is introduced through the nitrogen inlet P7 to protect the system with nitrogen filling. The gas containing oxygen and VOCs displaced is returned to the inlet through the displacement gas outlet pipeline P8 for reprocessing. A two-in-one oxygen concentration detector 12 is set on the displacement gas outlet pipeline P8 to monitor the oxygen concentration of the system. When the oxygen concentration < 5% or reaches the target safety value, the nitrogen protection of the system is turned off.

[0083] Because the adsorption heat value of methanol is high, while heat storage and heat exchange are carried out in the adsorption column T1, the system needs to supplement additional heat. Therefore, after turning off the nitrogen protection, it is switched to the preheating mode, and the heater 6 is started for circulating heating. When the temperature of the heated outlet waste gas P5 rises to 60 °C, the heating is stopped, and then it is switched to the vacuum desorption mode. The first vacuum pump 8 is turned on to carry out vacuum desorption regeneration of the adsorption material. A large amount of VOCs and a small amount of moisture are contained in the first desorption outlet waste gas P6. First, it is condensed by the primary condenser 9, with circulating water condensation and a condensation temperature of 40 °C, and then enters the secondary condenser 10 for secondary condensation, with a condensation temperature of 10 °C. The condensate generated after condensation enters the stratified solvent tank 11 for stratification and temporary storage.

[0084] This process sets up cyclic switching operations among four adsorption columns. Among them, two adsorption columns are respectively used for primary and secondary adsorption operations, one adsorption column is used for preheating operation, and one is used for desorption regeneration operation. Each adsorption column operates alternately and continuously according to the set time sequence steps.

[0085] Example 3

[0086] See Figure 3 , a pressure swing adsorption system, including a pretreatment unit, an adsorption and desorption device, and an evacuation unit P4 connected in sequence; the adsorption and desorption device is also respectively connected with a condensation circulation pipeline, a heating circulation pipeline, and a first desorption pipeline.

[0087] The adsorption and desorption device includes five adsorption columns T1 - T5 connected in parallel. Each of the adsorption columns is connected to the pretreatment unit, the evacuation unit P4, the condensation circulation pipeline, the heating circulation pipeline, and the desorption pipeline through valve pipelines.

[0088] The adsorption columns T1 - T5 include heat storage materials, specifically the reaction product of activated carbon and SiC, with an ash content of 80%. In other embodiments of this example, it can also be a mixture of activated carbon and SiC, with an ash content of 25%.

[0089] The pretreatment unit includes a temperature and humidity adjustment device 1, a filter 2, and a primary adsorption fan 3 connected in sequence. The adsorption columns T1 - T5 are provided with adsorption gas inlets, and the downstream of the primary adsorption fan 3 is connected to the adsorption gas inlets.

[0090] The adsorption columns T1 to T5 are also provided with adsorption gas outlets. The upstream of the condensation circulation pipeline is connected to the adsorption gas outlets, and the downstream is connected to the adsorption gas inlets; an adsorption condenser 4 and a secondary adsorption fan 5 are sequentially connected on the condensation circulation pipeline.

[0091] The adsorption columns T1 to T5 are also provided with heating gas outlets and heating gas inlets. The upstream of the heating circulation pipeline is connected to the heating gas outlets, and the downstream is connected to the heating gas inlets; a heater 6 and a heating fan 7 are sequentially connected on the heating circulation pipeline.

[0092] The adsorption columns T1 to T5 are also provided with first desorption gas outlets. The upstream of the first desorption pipeline is connected to the first desorption gas outlets, and a first vacuum pump 8, a primary condenser 9, a secondary condenser 10 and a layered solvent tank 11 are sequentially arranged downstream.

[0093] The pressure swing adsorption system is also provided with a second desorption gas outlet and a second desorption pipeline. The upstream of the second desorption pipeline is connected to the second desorption gas outlet, and a second vacuum pump 13 is arranged downstream and is connected to the primary condenser 9 through the second vacuum pump 13.

[0094] The pressure swing adsorption system further includes a nitrogen inlet P7 and a displacement gas outlet pipeline P8; the nitrogen inlet P7 is arranged on the pipeline between the heater 6 and the heating fan 7; the upstream of the displacement gas outlet pipeline P8 is connected to the pipeline upstream of the heater 6, and the downstream is connected to the pipeline upstream of the primary adsorption fan 3. An oxygen concentration detector 12 for one of two choices is arranged on the displacement gas outlet pipeline P8.

[0095] A pressure swing adsorption method based on the pressure swing adsorption system described above:

[0096] The waste gas from floating roof tanks and fixed tanks in a petrochemical industry tank farm has an exhaust air volume of 500 Nm 3 / h air volume, and the main components are low-volatile components in gasoline, kerosene, process white oil and diesel, most of which are alkanes with C5 to C20. The total concentration of the waste gas is 700 g / m 3 . The exhaust gas temperature is 35 °C and the relative humidity is 30%. It is required that the exhaust gas emission concentration after treatment < 30 mg / m 3 .

[0097] The workshop waste gas P1 enters the temperature and humidity adjustment device 1, the temperature is reduced to 20 °C, and enters the filter 2 to remove the particulate matter in the waste gas. The adsorption columns T1 to T5 are all filled with regenerative adsorption materials, and are introduced into the adsorption column T1 by the primary adsorption fan 3 for atmospheric pressure primary adsorption. The concentration of the exhaust gas P2 at the primary adsorption outlet is 1 to 60 g / m 3, the outlet temperature is 60 °C. To ensure the purification efficiency of the adsorption process and ensure that the outlet concentration meets the emission requirements, the waste gas P2 at the outlet of the first-stage adsorption enters the adsorption condenser 4 for cooling to obtain the condensed outlet waste gas P3, and the temperature is adjusted to 25 °C. Then, it is introduced into the adsorption column T2 by the second-stage adsorption fan 5 for atmospheric-pressure second-stage adsorption. After adsorption by the adsorption column T2, the emission concentration of the waste gas < 30 mg / m 3 , and is discharged through the evacuation unit P4.

[0098] There are problems of flammability and explosiveness in this waste gas. Before the preheating vacuum desorption operation, the system needs to be protected by nitrogen filling. Therefore, when the adsorption column T1 for the first-stage adsorption reaches adsorption saturation, nitrogen is added through the nitrogen inlet P7 to protect the system by nitrogen filling. The gas containing oxygen and VOCs displaced is returned to the inlet through the displacement gas outlet pipeline P8 for reprocessing. The displacement gas outlet pipeline P8 is provided with an oxygen concentration detector 12 that selects one of two to monitor the oxygen concentration of the system. When the oxygen concentration < 5% or reaches the target safety value, the nitrogen protection of the system is turned off.

[0099] After the nitrogen protection is turned off, it is switched to the preheating mode, and the heater 6 is started for circulating heating. When the temperature of the heated outlet waste gas P5 rises to 80 °C, the heating is stopped, and then it is switched to the vacuum desorption mode.

[0100] Because the adsorption concentration of the waste gas in the adsorption column is relatively high, when switching to the desorption and regeneration mode, to ensure that the system completes the desorption design requirements within the set switching time, a two-stage vacuum desorption mode is adopted. The first vacuum pump 8 is turned on to perform vacuum desorption and regeneration on the adsorption column T1. After reaching the set switching time, the second vacuum pump 13 is turned on to perform secondary vacuum desorption and regeneration on the adsorption column T1. A large amount of VOCs and a small amount of moisture are contained in the first desorption outlet waste gas P6 and the second desorption outlet waste gas P9. First, it is condensed by the first-stage condenser 9, and circulating water is used for condensation, and the condensation temperature is 40 °C. Then, it enters the second-stage condenser 10 for secondary condensation, and the condensation temperature is 10 °C. The condensate generated after condensation enters the stratified solvent tank 11 for stratification and temporary storage.

[0101] This process sets up a cyclic switching operation among five adsorption columns. Among them, two adsorption columns are respectively used for the first-stage and second-stage adsorption operations, one adsorption column is used for the preheating operation, and two are respectively used for the vacuum desorption and regeneration operations. Each adsorption column and vacuum pump operate alternately and continuously according to the set time sequence steps.

[0102] In summary, the pressure swing adsorption system and the pressure swing adsorption method provided by this application can be applied in different industrial fields, such as petrochemical tank area waste gas, loading and unloading waste gas, fine chemical industry, lithium battery separator industry, etc. Its system structure is compact, no additional large equipment is required, the floor area is small, and the process cost is low.

[0103] Please note that the technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification. The above embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

[0104] The above is the preferred implementation manner of the present application. It should be noted that for those of ordinary skill in the technical field, without departing from the principle of the present application, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present application.

Claims

1. A pressure swing adsorption system, characterized in that, Comprising: A pre-treatment unit, an adsorption and desorption device, and an evacuation unit connected in sequence; the adsorption and desorption device is also respectively connected to a condensation circulation pipeline, a heating circulation pipeline, and a first desorption pipeline; The adsorption and desorption device includes at least three adsorption columns connected in parallel, and each of the adsorption columns is connected to the pre-treatment unit, the evacuation unit, the condensation circulation pipeline, the heating circulation pipeline, and the desorption pipeline through valve pipelines.

2. The pressure swing adsorption system according to claim 1, wherein, The adsorption column includes a heat storage material or a heat storage adsorption material.

3. The pressure swing adsorption system according to claim 2, wherein The heat storage adsorption material includes a mixture or reaction product of an adsorption material and a heat storage material precursor; The ash content of the heat storage adsorption material is 25-80%.

4. The pressure swing adsorption system according to claim 3, characterized in that, The heat storage material precursor includes one or more of SiC, SiO2, Al2O3, or TiO2.

5. The pressure swing adsorption system according to any one of claims 1-4, characterized in that, The pre-treatment unit includes a temperature and humidity adjustment device, a filter, and a primary adsorption fan connected in sequence; The adsorption column is provided with an adsorption gas inlet, and the downstream of the primary adsorption fan is connected to the adsorption gas inlet.

6. The pressure swing adsorption system according to claim 5, characterized in that, The adsorption column is also provided with an adsorption gas outlet; The upstream of the condensation circulation pipeline is connected to the adsorption gas outlet, and the downstream is connected to the adsorption gas inlet; an adsorption condenser and a secondary adsorption fan are sequentially arranged on the condensation circulation pipeline.

7. The pressure swing adsorption system according to claim 6, wherein The adsorption column is also provided with a heating gas outlet and a heating gas inlet; The upstream of the heating circulation pipeline is connected to the heating gas outlet, and the downstream is connected to the heating gas inlet; a heating device and a heating fan are sequentially arranged on the heating circulation pipeline.

8. The pressure swing adsorption system according to claim 7, characterized in that, The adsorption column is also provided with a first desorption gas outlet; The upstream of the first desorption pipeline is connected to the first desorption gas outlet, and a first vacuum pump, a condensation device, and a stratified solvent tank are sequentially arranged downstream.

9. The pressure swing adsorption system according to claim 8, wherein, The system is also provided with a second desorption gas outlet and a second desorption pipeline. The upstream of the second desorption pipeline is connected to the second desorption gas outlet, and a second vacuum pump is arranged downstream and is connected to the condensation device and the stratified solvent tank through the second vacuum pump.

10. The pressure swing adsorption system according to claim 7, wherein, It also includes a nitrogen inlet and a displacement gas outlet pipeline; The nitrogen inlet is arranged on the pipeline between the heating device and the heating fan; The upstream of the displacement gas outlet pipeline is connected to the pipeline upstream of the heating device, and the downstream is connected to the pipeline upstream of the primary adsorption fan; An oxygen concentration detector for one of two is arranged on the displacement gas outlet pipeline.

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