CN107930340A - Temperature swing adsorption system and method for testing adsorption and desorption of volatile organic compounds - Google Patents

Abstract

The invention provides a temperature swing adsorption system and a temperature swing adsorption method for testing the adsorption quantity and desorption quantity of volatile organic compounds, and belongs to the technical field of temperature swing adsorption. The system comprises a raw material steel cylinder, a filter, a pressure reducing valve, a flowmeter I, a raw material volatilization tank, an adsorption tower, an analysis device, a desorption gas electric heater, an emptying unit and a purification unit; a valve I is arranged between the pressure reducing valve and the flowmeter I, a valve II is arranged between the raw material volatilization pot and the adsorption tower, a valve III and a back pressure valve I are arranged between the adsorption tower and the analysis device and between the adsorption tower and the emptying unit, and a valve IV and a back pressure valve II are arranged between the adsorption tower and the analysis device and between the adsorption tower and the purification unit; the raw material volatilization pot is also communicated with a back pressure valve I, and the middle of the raw material volatilization pot is provided with a valve V; a valve VI and a flow meter II are arranged between the desorption gas electric heater and the pressure reducing valve, and a valve VII is arranged between the desorption gas electric heater and the top of the adsorption tower. The system and the method can realize the measurement of the adsorption quantity and the desorption quantity of the volatile organic compounds, and provide a basis for the screening and the performance evaluation of the adsorbent.

Description

Temperature swing adsorption system and method for testing adsorption and desorption of volatile organic compounds

technical field

The invention belongs to the technical field of temperature swing adsorption, in particular to a temperature swing adsorption system and method for testing the adsorption and desorption amounts of volatile organic compounds.

Background technique

Temperature swing adsorption is the earliest industrialized cyclic adsorption process. It has the advantages of simple process, small investment, simple operation, and low maintenance. It is widely used in industry, such as gas drying, raw material gas purification, removal of waste gas or recovery of low concentration Solvents and waste gas and liquid treatment used in environmental protection, etc. With the improvement of temperature swing adsorption technology and the development of many new adsorbents, the application of temperature swing adsorption is becoming more and more extensive, and as people's requirements for environmental protection are getting higher and higher, many pollutants that currently plague humans can be properly removed by temperature swing adsorption. The treatment of temperature swing adsorption is expected to be more widely used in environmental protection, especially for the removal of low-concentration volatile organic compounds.

Contents of the invention

The purpose of the present invention is to provide a temperature swing adsorption device and method for testing the adsorption and desorption of volatile organic compounds. Through the device and method of the present invention, the test and analysis of the adsorption capacity and desorption capacity of different adsorbents to volatile organic compounds under different conditions can be realized. calculation, so as to provide basic data for engineering production, and also achieve the purpose of testing and screening adsorbents.

The object of the invention is achieved through the following technical solutions:

A temperature swing adsorption system for testing the adsorption and desorption of volatile organic compounds. The system includes a raw material cylinder connected in sequence, a filter, a pressure reducing valve, a flow meter I, a raw material volatilization tank, an adsorption tower, and an analysis device. The system also includes A desorption gas electric heater connected to the pressure reducing valve and the top of the adsorption tower, and an emptying unit and a purification unit connected to the top and bottom of the adsorption tower respectively;

A valve I is set between the pressure reducing valve and the flow meter I, a valve II is set between the raw material volatilization tank and the adsorption tower, and a valve III and a back valve are set between the adsorption tower and the analysis device and the emptying unit. Pressure valve I, valve IV and back pressure valve II are set between the adsorption tower, the analysis device and the purification unit;

The raw material volatilization tank is also communicated with the back pressure valve I and a valve V is arranged in the middle;

A valve VI and a flow meter II are set between the desorption gas-electric heater and the pressure reducing valve, and a valve VII is set between the desorption gas-electric heater and the top of the adsorption tower;

The purification unit is also in communication with the evacuation unit.

In the adsorption system of the present invention, the raw steel cylinder provides the gas source for the whole device, and the gas in the raw steel cylinder can be air, nitrogen, argon, carbon dioxide and other gases. The main purpose of the filter is to protect the pressure reducing valve and the flow meter, and to remove dust and other particles in the gas of the raw material cylinder. The pressure reducing valve decompresses the high-pressure gas from the previous raw material cylinder to the test pressure required for the test. The raw material volatilization tank is used to store the organic matter to be tested, and the organic matter in the raw material volatilization tank passes through the flow meter I to bring the organic matter into the adsorption tower behind. The analysis device is mainly used to analyze and test the concentration of organic matter in the adsorption and desorption tail gas. The desorption gas electric heater heats the gas coming from the flowmeter II to the temperature required for desorption. The purification unit removes the high-concentration organic matter in the desorption tail gas to avoid impact on the environment, and the emptying unit discharges the adsorption tail gas and the purified desorption tail gas to a designated ventilation place.

As a specific embodiment of the temperature swing adsorption system for testing the adsorption and desorption of volatile organic compounds in the present invention, the system also includes a raw material gas dilution buffer arranged between the raw material volatilization tank and valve II and valve V tank, the raw material gas dilution buffer tank is also connected with the pressure reducing valve, and a valve VIII and a flow meter III are arranged in the middle. When the concentration of organic matter coming from the raw material volatilization tank is high, the organic matter can be diluted to the required concentration by adjusting the flow meter III to control the intake amount to the raw material gas dilution buffer tank.

As a specific embodiment of the temperature swing adsorption system for testing the adsorption and desorption of volatile organic compounds in the present invention, the flowmeter I, flowmeter II and flowmeter III are mass flowmeters with control functions.

As a specific embodiment of the temperature swing adsorption system for testing the adsorption and desorption of volatile organic compounds in the present invention, a coil is arranged in the raw material volatilization tank, and the coil is connected with the circulation temperature control unit, and the medium of the circulation temperature control unit is It is water or ethylene glycol, and the temperature in the raw material volatilization tank can be controlled at -10-100°C through the circulation temperature control unit.

As a specific embodiment of the temperature swing adsorption system for testing the adsorption and desorption of volatile organic compounds in the present invention, the back pressure valve I and the back pressure valve II can control the adsorption pressure and desorption pressure of the system at 0-5 MPa; The outside of the adsorption tower is equipped with a thermal insulation and heating jacket, which can control the temperature of the adsorption tower to ≤300°C. By controlling the temperature of the adsorption tower, the adsorption capacity of the adsorbents at different temperatures to organic matter can be tested.

As a specific embodiment of the temperature swing adsorption system for testing the adsorption and desorption of volatile organic compounds in the present invention, the valves I, V, VI, and VIII are ball valves, and the valves II, III, and IV are ball valves. , valve VII is a high temperature stop valve, the back pressure valve II is a high temperature resistant back pressure valve, and the back pressure valve I is an ordinary back pressure valve; and the pressure of the back pressure valve I and the back pressure valve II is set according to the actual test needs.

Utilize the method for testing volatile organic compound adsorption capacity and desorption capacity of described system, comprise the following steps:

1) Load volatile organic compounds into the raw material volatilization tank, and load adsorbent into the adsorption tower.

2) Turn on the cycle temperature control unit, control the temperature in the raw material volatilization tank to volatilize volatile organic compounds, open the raw material gas cylinder, and the raw material gas enters the pressure reducing valve after being filtered by the filter.

3) Open valve Ⅰ, valve Ⅷ and valve Ⅴ, and set the back pressure of back pressure valve Ⅰ. The raw material gas enters the raw material volatilization tank to take away the volatilized organic matter, enters the raw material gas dilution buffer tank for dilution, and then enters the analysis The device measures the concentration of organic matter in the raw material gas. At this time, adjust the flow meter I and flow meter III to make the concentration _C1 of organic matter in the raw material gas meet the requirements, and record the flow meter I and flow meter III as V ₁ and V ₃ .

4) When the content of organic matter in the feed gas is stable, close valve V, open valve II and valve III, the adsorbent in the adsorption tower starts to adsorb organic matter, and analyze the concentration of organic matter in the tail gas from the top of the adsorption tower through the analysis device, and at the same time pass Evacuate the exhaust system to vent the tail gas. When the content of organic matter in the tail gas reaches the breakthrough concentration, close the valves I, VIII, II, III, flow meter I, and flow meter III, and close the circulation temperature control unit. Flow rate V ₁ , flow rate V ₂ of flow meter III, concentration C ₁ of organic matter in the feed gas, adsorption time t ₁ , and the loading mass of the catalyst are used to calculate the penetration adsorption amount of organic matter by the adsorbent.

By controlling the flow rate and concentration of the feed gas, the back pressure of the back pressure valve I, the temperature control temperature outside the adsorption tower and changing the loading amount of the adsorbent to study the volatility of the adsorbent at different pressures, space velocities, temperatures and concentrations. adsorption of organic matter.

5) After the adsorption is completed, open the valve VI and flow meter II, control the required desorption gas flow through the flow meter II and record it as V ₃ , turn on the desorption gas electric heater to control the temperature of the desorption gas, and then open the valve VII , Valve IV, set the back pressure of back pressure valve II, analyze the concentration C ₂ of organic matter in the desorption tail gas through the analysis device, and at the same time, the desorption tail gas enters the purification unit for purification and then is emptied. When the content of organic matter in the desorption tail gas is reduced to the required When the concentration is _desorbed , close valve VI, valve VII, and valve IV, close the _desorption gas electric heater and flow meter _II , and close the raw gas cylinder at the same time. And the mass of the adsorbent is used to calculate the desorption amount of the adsorbent to the organic matter.

By setting different desorption gas flow rate, desorption gas temperature and back pressure of back pressure valve II, the desorption amount of adsorbent after adsorbing organic matter can be studied at different temperatures, space velocities and pressures.

As a specific embodiment of the method for testing the adsorption capacity and desorption capacity of volatile organic compounds described in the present invention, the formula for calculating the breakthrough adsorption capacity is:

In the formula (1), q is the breakthrough adsorption amount, ml/g; C1 is the concentration of organic matter in the raw material gas before adsorption, PPm; _t1 is the adsorption time, h; V1 is the value _of the flow meter I, ml/h ; V ₂ is the value of the flow meter III, ml/h; m is the mass of the loaded adsorbent, g.

The breakthrough adsorption capacity is the organic matter adsorbed by the adsorbent during the process when the adsorbent starts to adsorb the organic matter in the exhaust gas when the concentration of the organic matter reaches 5% of the tail gas concentration in the feed gas. The adsorption capacity per unit mass of the adsorbent calculated by formula (1) is slightly Large, but the error is very small, the precise algorithm should be:

Among them, t ₀ is the time when organic matter begins to appear in the exhaust gas, and C is the concentration of organic matter in the _exhaust gas during the process from the beginning of organic matter in the exhaust gas to the time of breakthrough. V is the volume of the dead _space of the system, and C is the concentration of organic matter in the dead _space of the system. Since the time from the beginning of organic matter in the tail gas to the time when the organic matter _penetrates the adsorbent is relatively short, and the concentration of C in this process is relatively low, it can be ignored. The dead _space V of the system is relative to the adsorption flow rate V ₁ +V ₂ is also very small, and C _space is also relatively small, so this item can also be ignored. The inventor calculated the breakthrough adsorption capacity of the adsorbent by optimizing the obtained formula (1), controlled the error within an acceptable range of 5%, simplified the calculation formula of the adsorption capacity, reduced the difficulty of calculating the adsorption capacity, and saved calculation time.

As a specific embodiment of the method for testing the adsorption capacity and desorption capacity of volatile organic compounds described in the present invention, the calculation formula of the desorption capacity is:

In formula (2), Q is the desorption amount, ml/g; V ₃ is the reading of flowmeter II, ml/h; t ₂ is the desorption time, h; C ₂ is the concentration of organic matter in the desorption tail gas, PPm; The mass of the adsorbent, g.

The desorption amount of the present invention is the integral of the desorption flow rate multiplied by the desorption concentration to the desorption time and then divided by the mass of the adsorbent to obtain the desorption amount per unit mass of the adsorbent. The desorption amount calculated by formula (2) is highly accurate.

As a specific embodiment of the method for testing the adsorption and desorption of volatile organic compounds in the present invention, the breakthrough concentration is when the organic content in the exhaust gas is 5% of the organic content in the feed gas.

Compared with the prior art, the present invention has the following beneficial effects:

The temperature swing adsorption system of the present invention has simple structure, convenient operation and wide applicability, and can be used for the measurement and research of the adsorption capacity and desorption capacity of various volatile organic compounds, and realizes different adsorbent pairs under different temperatures, space velocities, concentrations and pressures. The determination of the adsorption capacity and desorption capacity of volatile organic compounds provides the basis for the screening and performance evaluation of volatile organic compound adsorbents, and provides basic data for the engineering design of temperature swing adsorption.

Description of drawings

Fig. 1 is a schematic structural diagram of a temperature swing adsorption system for testing the adsorption and desorption of volatile organic compounds according to the present invention.

Reference signs: 1-raw material gas cylinder, 2-filter, 3-pressure reducing valve, 4-valve Ⅰ, 5-flow meter Ⅰ, 6-cycle temperature control unit, 7-raw material volatilization tank, 8-valve Ⅷ, 9-flow meter Ⅲ, 10-feed gas dilution buffer tank, 11-valve Ⅴ, 12-valve Ⅵ, 13-flow meter Ⅱ, 14-desorption gas electric heater, 15-valve Ⅶ, 16-valve Ⅱ, 17 - adsorption tower, 18 - valve III, 19 - back pressure valve I, 20 - valve IV, 21 - back pressure valve II, 22 - analysis device, 23 - emptying unit, 24 - purification unit.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Example 1

In this embodiment, the temperature swing adsorption system of the present invention is used to test the adsorption and desorption of low-concentration toluene in the air with activated carbon as the adsorbent. The test system is shown in Figure 1, and the specific operation process is as follows:

1. Load 300ml of toluene into the raw material volatilization tank 7, load 10g of gac into the adsorption tower 17, and control the temperature of the adsorption tower to be 30°C.

2. Turn on the cycle temperature control system 6, use water as the temperature control medium, control the temperature of the raw material volatilization tank 7 at 10°C, open the raw material gas cylinder 1, the air will enter the pressure reducing valve 3 after being filtered by the filter 2, and the pressure reducing valve 3 will The outlet pressure is controlled at 0.3MPa.

3. Open valve I4, valve VIII8, and valve V11, set the back pressure of back pressure valve I19 to be an absolute pressure of 100kPa, then set flowmeter I5 and flowmeter III9, and analyze the concentration of toluene in the feed gas through analysis device 22, Control the concentration of toluene in the feed gas to about 50PPm by adjusting flowmeter I5 and flowmeter III9. When the toluene concentration _C1 in the feed gas is stable at 50PPm, the value V1 of the flow meter _I5 is 0.8L/h, and the value V2 of the flow meter _III9 is 120L/h.

4. After the toluene content of the raw material gas is stable, close the valve V11, open the valves II16 and III18, the activated carbon in the adsorption tower 17 starts to adsorb toluene, and analyze the concentration of toluene in the tail gas from the top of the adsorption tower through the analysis device 22, and at the same time through the exhaust The empty unit 23 vents the tail gas, and when the toluene content in the tail gas is 2.5PPm, it is breakthrough. The breakthrough adsorption time _t1 is 4.2h. After breakthrough, close valve I4, valve VIII8, valve II16, valve III18, flowmeter I5, flowmeter III9, and close the circulation temperature control unit 6.

The flow rate V ₁ of the flow meter I5, the flow rate V ₂ of the flow meter III 9, the concentration C ₁ of organic matter in the feed gas, the adsorption time t ₁ , and the mass of the activated carbon are brought into the breakthrough adsorption calculation formula (Equation 1) for calculation The breakthrough adsorption capacity of activated carbon to toluene is 2.54ml/g.

5. After the adsorption is completed, open the valve Ⅵ12 and the flowmeter Ⅱ13, control the desorption gas (air coming from the decompression valve) flow rate _V3 to 15L/h through the flowmeter Ⅱ13, turn on the desorption gas electric heater 14, and control the desorption gas flow rate V3 to 15L/h. The suction temperature is 150°C, then open the valve VII15 and IV20, set the back pressure of the back pressure valve II21 to 100kPa, analyze the toluene concentration _C2 in the desorption tail gas through the analysis device, and the desorption gas enters the purification unit 24 for purification treatment and is discharged Empty, when the toluene content in the desorption tail gas drops to the required concentration of 100PPm, close valve VI12, valve VII15, valve IV20, close the desorption gas electric heater 14 and flow meter II13, and close the gas source of the front raw material gas cylinder 1 at the same time.

The relationship between the desorption tail gas temperature and concentration and time is shown in Table 1 below. Substitute the flow rate V ₃ of the flow meter II, the desorption time t ₂ , the desorption tail gas concentration C ₂ and the mass of activated carbon into the desorption calculation formula (Formula 2) to calculate the desorption capacity. The desorption amount of toluene was 1.94ml/g.

The relationship between table 1 embodiment 1 desorption tail gas temperature and concentration and time

Example 2

In this embodiment, the temperature swing adsorption system of the present invention is used as the adsorbent to test the adsorption and desorption of low-concentration butanol in the air under normal pressure. The test system is shown in Figure 1, and the specific operation process is as follows:

1. Load 350ml butanol in the raw material volatilization tank 7, and load 2g activated carbon fibers in the adsorption tower 17. The temperature of the adsorption tower is controlled at 30°C.

2. Open the cycle temperature control unit 6, use water as the temperature control medium, control the temperature of the raw material volatilization tank 7 at 20°C, open the raw material gas cylinder 1, the air will enter the pressure reducing valve 3 after being filtered by the filter 2, and the pressure reducing valve 3 The outlet pressure is controlled at 0.3MPa.

3. Open valve I4, valve VIII8, and valve V11, set the back pressure of back pressure valve I19 as an absolute pressure of 100kPa, then set flowmeter I5, flowmeter III9, and analyze the concentration of butanol in the raw material gas through analysis device 22, Control the concentration of butanol in the feed gas at about 60PPm by adjusting flowmeter I5 and flowmeter III9. When the concentration _C1 of butanol in the feed gas is stable at 61PPm, the value V1 of the flowmeter _I5 is 1.1L/h, and the value V2 of the flowmeter _III9 is 230L/h.

4. After the butanol content in the raw material gas is stable, close the valve V11, open the valves II16 and III18, the activated carbon fibers in the adsorption tower 17 start to adsorb butanol, and analyze the butanol content in the tail gas from the top of the adsorption tower 17 through the analysis device 22. At the same time, the tail gas is emptied through the emptying unit 23. When the butanol content in the tail gas is 3PPm, it is breakthrough. The breakthrough adsorption time _t1 is 29.4h. After breakthrough, close valve I4, valve VIII8, valve II16, valve III11, flowmeter I5, flowmeter III9, and close the circulation temperature control unit 6.

The flow rate V ₁ of the flow meter I5, the flow rate V ₂ of the flow meter III 9, the concentration C ₁ of organic matter in the feed gas, the adsorption time t ₁ , and the loading mass of the activated carbon fiber are brought into the formula for calculating the breakthrough adsorption capacity (Formula 1) The calculated breakthrough adsorption capacity of activated carbon fiber to butanol is 207.2ml/g.

5. After the adsorption is completed, replace the raw material gas cylinder 1 with a nitrogen cylinder, open the valve Ⅵ12 and the flowmeter Ⅱ13, and control the flow rate V ₃ of the desorption gas (nitrogen from the pressure reducing valve) required by the flowmeter Ⅱ13 to 20L/ h, turn on the desorption gas electric heater 14, control the temperature of the desorption gas to 140°C, then open the valve VII15 and valve IV20, set the back pressure of the back pressure valve II21 to an absolute pressure of 100kPa, and analyze the middle part of the desorption tail gas through the analysis device 22 Alcohol concentration C ₂ , the desorption gas enters the desorption gas purification unit 24 for purification and then is emptied. When the butanol content in the desorption tail gas decreases to the required concentration of 1000PPm in the experiment, close valve VI12, valve VII15, and valve IV20 to close the desorption Gas-electric heater 14 and flow meter II 13, while closing the front cylinder gas source.

The relationship between the desorption tail gas temperature and concentration and time is shown in Table 2 below. Substitute the flow rate V ₃ of the flow meter II, the desorption time t ₂ , the desorption tail gas concentration C ₂ and the filling mass of activated carbon fibers into the desorption calculation formula (Formula 2) to calculate activated carbon The desorption amount of butanol to the fiber was 186.5ml/g.

The relation of table 2 embodiment 2 desorption tail gas temperature and concentration and time

Example 3

The present embodiment adopts the temperature swing adsorption system of the present invention and uses activated carbon fiber as an adsorbent to test the adsorption and desorption of 250PPm butanol in the air under normal pressure. The test system is shown in Figure 1, and the specific operation process is as follows:

1. Load 400ml butanol in the raw material volatilization tank 7, and load 2g activated carbon fibers in the adsorption tower 17. The temperature of the adsorption tower is 30°C.

2. Open the cycle temperature control unit 6, use water as the temperature control medium, control the temperature of the raw material volatilization tank 7 at 20°C, open the raw material gas cylinder 1, the air will enter the pressure reducing valve 3 after being filtered by the filter 2, and the pressure reducing valve 3 The outlet pressure is controlled at 0.3MPa.

3. Open valve I4, valve VIII8, and valve V11, set the back pressure of back pressure valve I19 as absolute pressure 100kPa, then set flowmeter I5, flowmeter III9, and analyze the content of butanol in the feed gas through analysis device 22, Control the concentration of butanol in the feed gas at about 250PPm by adjusting flowmeter I5 and flowmeter III9. When the concentration _C1 of butanol in the raw material gas is analyzed and stabilized at 249.5PPm, the value V1 of the flowmeter _I5 is 4.1L/h, and the value V2 of the flowmeter _III9 is 230L/h.

4. After the butanol content of the raw material gas is stable, close the valve V11, open the valves II16 and III18, the activated carbon fibers in the adsorption tower 17 start to adsorb butanol, and analyze the concentration of butanol in the tail gas from the top of the adsorption tower through the analysis device 22 , and exhaust the tail gas through the emptying unit 23 at the same time, when the butanol content in the tail gas is 12PPm, it is breakthrough. The breakthrough adsorption time _t1 is 7.5h. After breakthrough, close valve I4, valve VIII8, valve II16, valve III18, flowmeter I5, flowmeter III9, and close the circulation temperature control unit 6.

The flow rate V ₁ of the flow meter I5, the flow rate V ₂ of the flow meter III 9, the concentration C ₁ of organic matter in the feed gas, the adsorption time t ₁ , and the loading mass of the activated carbon fiber are brought into the formula for calculating the breakthrough adsorption capacity (Formula 1) Calculate the penetration adsorption capacity of activated carbon fiber to 250PPm butanol to be 219.03ml/g.

5. After the adsorption is completed, replace the raw material gas cylinder 1 with a nitrogen cylinder, open the valve Ⅵ12 and the flowmeter Ⅱ13, and control the required desorption gas (nitrogen from the pressure reducing valve) flow rate V ₃ to 22L/ h, turn on the desorption gas electric heater 14, control the temperature of the desorption gas to 160°C, then open the valve VII15 and valve IV20, set the back pressure of the back pressure valve II21 to an absolute pressure of 100kPa, and analyze the desorption tail gas through the analysis device 22 The concentration of butanol is C ₂ , and the desorption gas enters the desorption gas purification unit 24 for purification and then is emptied. When the butanol content in the desorption tail gas is reduced to the required concentration of 1000PPm in the experiment, close valve VI12, valve VII15, and valve IV20, and close the desorption gas. Inhale electric heater 14 and flowmeter II 13, and close the gas source of the front cylinder at the same time.

The relationship between the desorption tail gas temperature and concentration and time is shown in Table 3 below. Substitute the flow V ₃ of the flow meter II, the desorption time t ₂ , the desorption tail gas concentration C ₂ and the mass of activated carbon fiber into the desorption calculation formula (Formula 2) to calculate the activated carbon The desorption capacity of the fiber to 250PPm butanol is 193.58ml/g.

Table 3 embodiment 3 desorption tail gas temperature and the relationship between concentration and time

time (min) Desorption tail gas temperature (°C) Concentration of butanol in desorption tail gas (PPm) 2 29.1 49 8 36.5 65 11 52.2 668 14 68.5 14822 18 93.5 15960 twenty two 117.4 20072 25 132 20223 29 145.8 21395 33 153.2 9838 39 157.2 6883 44 159.3 4476 47 160 3275 51 160.3 2496 54 159.8 1984 58 159.8 1614 62 159.8 1338 66 159.8 1089 70 159.8 888

Example 4

In this embodiment, the temperature swing adsorption system of the present invention is used to test the adsorption and desorption of low-concentration ethyl acetate in the air under normal pressure with activated carbon fiber as the adsorbent. The test system is shown in Figure 1, and the specific operation process is as follows:

1. Load 380ml ethyl acetate in the raw material volatilization tank 7, and load 2g activated carbon fiber in the adsorption tower 17. Control the temperature of the adsorption tower to be 25°C.

2. Turn on the cycle temperature control unit 6, use water as the temperature control medium, control the temperature of the raw material volatilization tank 7 at 10°C, open the raw material gas cylinder 1, the air will enter the pressure reducing valve 3 after being filtered by the filter 2, and the pressure reducing valve 3 The outlet pressure is controlled at 0.3MPa.

3. Open valve Ⅰ4, valve Ⅷ8, and valve Ⅴ11, set the back pressure of back pressure valve Ⅰ19 to absolute pressure 100kPa, then set flowmeter Ⅰ5 and flowmeter Ⅲ9, and analyze the content of ethyl acetate in the feed gas through analysis device 22 , by adjusting the flow meter I5 and flow meter III9 to control the ethyl acetate content of the raw material gas at about 60PPm. When the concentration _C1 of ethyl acetate in the feed gas is stable at _59PPm , the value V2 of flowmeter I5 is 0.8L/h, and the value V2 of flowmeter _III9 is 308L/h.

4. After the content of ethyl acetate in raw material gas is stable, close valve Ⅴ11, open valve Ⅱ16 and valve Ⅲ18, the activated carbon fiber in the adsorption tower 17 starts to adsorb ethyl acetate, and analyze the ethyl acetate in the tail gas from the top of the adsorption tower through analysis device 22 At the same time, the tail gas is emptied through the emptying unit 23. When the content of ethyl acetate in the tail gas is 3PPm, it is breakthrough. The breakthrough adsorption time _t1 is 4.8h. After breakthrough, close valve I4, valve VIII8, valve II16, valve III18, flowmeter I5, flowmeter III9, and close the circulation temperature control unit 6.

The flow rate V ₁ of the flow meter I5, the flow rate V ₂ of the flow meter III 9, the concentration C ₁ of organic matter in the feed gas, the adsorption time t ₁ , and the loading mass of the activated carbon fiber are brought into the formula for calculating the breakthrough adsorption capacity (Formula 1) Calculate the penetration adsorption capacity of activated carbon fiber to ethyl acetate to be 43.7ml/g.

5. After the adsorption is completed, open the valve Ⅵ12 and the flow meter Ⅱ13, control the required desorption gas (air from the pressure reducing valve) flow V ₃ to 28.9L/h through the flow meter Ⅱ13, and turn on the desorption gas electric heater 14 , control the temperature of the stripping gas to 100°C, then open valve VII15 and valve IV20, set the back pressure of the back pressure valve II21 to an absolute pressure of 100kPa, analyze the concentration C2 of ethyl acetate in the stripping tail gas through the analysis device ₂₂ , and analyze the concentration C2 of the stripping gas After entering the desorption gas purification unit 24 for purification treatment, it is emptied. When the content of ethyl acetate in the desorption tail gas is reduced to the required concentration of 500PPm in the experiment, close valve VI, valve VII, and valve IV, and close the desorption gas electric heater and flow meter II. , and at the same time close the gas source of the front cylinder.

The relationship between the desorption tail gas temperature and concentration and time is shown in Table 4 below. Substitute the flow V ₃ of the flow meter II, the desorption time t ₂ , the desorption tail gas concentration C ₂ and the mass of activated carbon fiber into the desorption calculation formula (Formula 2) to calculate the activated carbon. The desorption capacity of the fiber to ethyl acetate was 39.6 ml/g.

The relationship between table 4 embodiment 4 desorption tail gas temperature and concentration and time

time (min) Desorption tail gas temperature (°C) Concentration of ethyl acetate in desorption tail gas (PPm) 1 22.2 43 3 23.2 80 6 29.6 286 10 40.5 1180 14 58.1 2599 18 72.5 4203 twenty one 81.9 5062 25 89.5 4734 29 95.3 3914 34 99.3 2958 39 99.9 2194 42 100 1783 46 99.7 1507 58 99.8 876 63 99.8 762 69 99.8 668 73 99.8 600 83 99.8 528 89 99.8 489

Example 5

In this embodiment, the temperature swing adsorption system of the present invention is used to test the adsorption and desorption of low-concentration benzene in the air under normal pressure with molecular sieve as the adsorbent. The test system is shown in Figure 1, and the specific operation process is as follows:

1. Load 400ml benzene in the raw material volatilization tank 7, and load 4g molecular sieve in the adsorption tower 17. Control the temperature of the adsorption tower to be 30°C.

2. Turn on the cycle temperature control unit 6, use ethylene glycol as the temperature control medium, control the temperature of the raw material volatilization tank 7 at 5°C, open the raw material gas cylinder 1, and the air will enter the pressure reducing valve 3 after being filtered by the filter 2, and the pressure will be reduced The outlet pressure of valve 3 is controlled at 0.3MPa.

3. Open valve I4, valve VIII8, and valve V11, set the back pressure of back pressure valve I19 to be an absolute pressure of 100kPa, then set flowmeter I5 and flowmeter III9, and analyze the content of benzene in the raw material gas through analysis device 22, Control the content of benzene in the feed gas to about 65PPm by adjusting flowmeter I5 and flowmeter III9. When the concentration C ₁ of benzene in the feed gas is stable at 64PPm, the value V ₁ of the flow meter I5 is 0.8L/h, and the value V ₂ of the flow meter III 9 is 92L/h.

4. After the benzene content of raw material gas is stable, close valve V11, open valve II16 and valve III18, the molecular sieve in the adsorption tower 17 starts to adsorb benzene, and analyze the benzene content in the tail gas from the top of the adsorption tower through the analysis device 22. The empty unit 23 vents the tail gas, and when the benzene content in the tail gas is 3PPm, it is breakthrough. The breakthrough adsorption time _t1 is 2.5h. After breakthrough, close valve I4, valve VIII8, valve II16, valve III18, flowmeter I5, flowmeter III9, and close the circulation temperature control unit 6.

The flow rate V ₁ of flow meter I5, the flow rate V ₂ of flow meter III 9, the concentration C ₁ of organic matter in the feed gas, the adsorption time t ₁ , and the filling mass of molecular sieves are brought into the breakthrough adsorption calculation formula (Equation 1) for calculation The breakthrough adsorption capacity of molecular sieve to ethylbenzene is 3.7ml/g.

5. After the adsorption is completed, open the valve Ⅵ12 and the flowmeter Ⅱ13, control the desorption gas (air coming from the decompression valve) flow rate _V3 to 15L/h through the flowmeter Ⅱ13, turn on the desorption gas electric heater 14, and control the desorption gas flow rate V3 to 15L/h. The suction temperature is 100°C, then open the valve VII15 and IV20, set the back pressure of the back pressure valve II21 to an absolute pressure of 100kPa, analyze the concentration C ₂ of the desorbed tail gas through the analysis device 22, and the desorbed gas enters the desorbed gas for purification After unit 24 is purified and emptied, when the benzene content in the desorption tail gas is reduced to the required concentration of 200PPm for the experiment, close valve VI12, valve VII15, and valve IV20, close the desorption gas electric heater 14 and flow meter II13, and close the front cylinder gas at the same time. source.

The relationship between the desorption tail gas temperature and concentration and time is shown in Table 5 below. Substitute the flow rate V ₃ of the flow meter II, the desorption time t ₂ , the desorption tail gas concentration C ₂ and the molecular sieve filling mass into the desorption calculation formula (Formula 2) to calculate the molecular sieve pair The desorption amount of benzene was 3.3 ml/g.

The relationship between table 5 embodiment 5 desorption tail gas temperature and concentration and time

time (min) Desorption tail gas temperature (°C) Benzene concentration in desorption tail gas (PPm) 1 22.7 29 4 22.8 74.7 10 27.6 90 12 35 165 18 58.7 981 twenty one 69.2 1828 twenty three 77.6 2293 27 86.6 4549 31 93.7 5394 35 98 4610 40 100.2 2803 44 100.1 1790 47 100.1 1245 51 99.9 845 56 99.9 582 61 99.9 440 65 99.9 352 74 99.9 242 80 99.9 198

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (10)

1. test the temperature swing adsorption system of volatile organic matter adsorbance and desorption quantity, it is characterised in that the system comprises according to The raw material steel cylinder of secondary connection, filter, pressure reducing valve, flow meter I, volatility of raw material tank, adsorption tower, analytical equipment, the system is also Including with pressure reducing valve and the stripping gas electric heater that connect of absorption column overhead and respectively with adsorbing column overhead and bottom of towe connects Empty unit and clean unit；

Valve I is provided between the pressure reducing valve and flow meter I, valve II, institute are provided between the volatility of raw material tank and adsorption tower State and valve III and counterbalance valve I are provided between adsorption tower and analytical equipment and emptying unit, the adsorption tower is with analytical equipment and only Valve IV and counterbalance valve II are provided between change unit；

The volatility of raw material tank is also connected with counterbalance valve I and centre is provided with valve V；

Valve VI and flow meter II are provided between the stripping gas electric heater and pressure reducing valve, the stripping gas electric heater is with inhaling Valve VII is provided between attached column overhead；

The clean unit is also connected with emptying unit.

2. the temperature swing adsorption system of test volatile organic matter adsorbance and desorption quantity as claimed in claim 1, it is characterised in that It is former the system also includes the unstripped gas dilution buffer tank for being arranged between volatility of raw material tank and valve II, valve V and communicating therewith Material gas dilution buffer tank is also connected with pressure reducing valve and centre is provided with valve VIII and flowmeter III.

3. the temperature swing adsorption system of test volatile organic matter adsorbance and desorption quantity as claimed in claim 1, it is characterised in that The flow meter I, flow meter II and flowmeter III are the mass flowmenter with control function.

4. the temperature swing adsorption system of test volatile organic matter adsorbance and desorption quantity as claimed in claim 1, it is characterised in that Coil pipe is provided with the volatility of raw material tank, coil pipe is connected with loop temperature-control unit, and the medium of loop temperature-control unit is water or second Glycol, can make the temperature control in volatility of raw material tank at -10~100 DEG C by loop temperature-control unit.

5. the temperature swing adsorption system of test volatile organic matter adsorbance and desorption quantity as claimed in claim 1, it is characterised in that The counterbalance valve I and counterbalance valve II can be with the adsorptive pressures and desorption pressures of control system in 0~5MPa；Outside the adsorption tower Equipped with heat-preserving heating jacket, temperature≤300 DEG C of adsorption tower can be controlled.

6. the temperature swing adsorption system of test volatile organic matter adsorbance and desorption quantity as claimed in claim 2, it is characterised in that The valve I, valve V, valve VI, valve VIII are ball valve, the valve II, valve III, valve IV, and valve VII is high temperature break valve, the counterbalance valve II For high temperature resistant counterbalance valve.

7. claim 1 to 6 any one of them system testing volatile organic matter adsorbance and the method for desorption quantity are utilized, its It is characterized in that, comprises the following steps：

1) load volatile organic matter in volatility of raw material tank, and load adsorbent in adsorption tower；

2) ON cycle control temperature unit, controls temperature in volatility of raw material tank volatile organic matter is volatilized, opens raw material gas cylinder, Unstripped gas enters pressure reducing valve after being filtered；

3) opening valve I, valve VIII, valve V, and I back-pressure of counterbalance valve is set, unstripped gas, which enters in volatility of raw material tank, takes away volatilization Organic matter and enter unstripped gas dilution buffer tank in be diluted, subsequently into analytical equipment in unstripped gas organic matter it is dense Degree is measured, and at this time, adjusting flow meter I, flowmeter III make the concentration C of organic matter in unstripped gas₁Reach requirement, and by flow Meter I and flowmeter III are recorded as V₁And V₃；

4) valve V is closed after content of organics is stablized in unstripped gas, opens valve II, valve III, adsorbent starts to adsorb in adsorption tower Organic matter, and be by the concentration of analytical equipment analysis organic matter from the tail gas that absorption column overhead comes out, while by emptying Tail gas is vented by system, when content of organics reaches breakthrough concentration in tail gas, closes valve I, valve VIII, valve II, valve III and flowmeter Ith, flowmeter III, closes loop temperature-control unit, according to the flow V of flow meter I₁, flowmeter III flow V₂, it is organic in unstripped gas The concentration C of thing₁, adsorption time t₁And the filling quality of catalyst penetrates adsorbance to calculate adsorbent to organic matter.

5) after the completion of adsorbing, valve VI and flow meter II are opened, the desorption throughput needed by flow meter II control is simultaneously denoted as V₃, Open stripping gas electric heater to be controlled stripping gas temperature, then open valve VII, valve IV, set the back pressure pressure of counterbalance valve II Power, the concentration C of organic matter in desorption tail gas is analyzed by analytical equipment₂, while desorb tail gas and enter clean unit purified treatment After empty, when desorbing content of organics in tail gas and being reduced to the desorption concentration of requirement close valve VI, valve VII, valve IV, close solution Air-breathing electric heater and flow meter II, simultaneously close off raw material gas cylinder, according to the flow V of flow meter II₃, desorption time t₂Conciliate Inhale tail gas concentration C₂And adsorbent filling Mass Calculation adsorbent is to the desorption quantity of organic matter.

8. test volatile organic matter adsorbance and the method for desorption quantity as claimed in claim 7, it is characterised in that described to wear The calculation formula of adsorbance is thoroughly：

<mrow> <mi>q</mi> <mo>=</mo> <mfrac> <mrow> <msub> <mi>C</mi> <mn>1</mn> </msub> <mo>*</mo> <msub> <mi>t</mi> <mn>1</mn> </msub> <mo>*</mo> <mrow> <mo>(</mo> <msub> <mi>V</mi> <mn>1</mn> </msub> <mo>+</mo> <msub> <mi>V</mi> <mn>2</mn> </msub> <mo>)</mo> </mrow> </mrow> <mi>m</mi> </mfrac> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </mrow>

In formula (1), q is to penetrate adsorbance, ml/g；C₁For the concentration of organic matter in unstripped gas before absorption, PPm；t₁During to adsorb Between, h；V₁For the numerical value of flow meter I, ml/h；V₂For the numerical value of flowmeter III, ml/h；M be filling adsorbent quality, g.

9. test volatile organic matter adsorbance and the method for desorption quantity as claimed in claim 7, it is characterised in that the solution The calculation formula of pipette is：

<mrow> <mi>Q</mi> <mo>=</mo> <mfrac> <mrow> <msub> <mi>V</mi> <mn>3</mn> </msub> <msubsup> <mo>&amp;Integral;</mo> <mn>0</mn> <msub> <mi>t</mi> <mn>2</mn> </msub> </msubsup> <msub> <mi>C</mi> <mn>2</mn> </msub> <mi>d</mi> <mi>t</mi> </mrow> <mi>m</mi> </mfrac> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>2</mn> <mo>)</mo> </mrow> </mrow>

In formula (2), Q is desorption quantity, ml/g；V₃For the numerical value of flow meter II, ml/h；t₂For desorption time, h；C₂To desorb tail gas Middle organic concentration, PPm；M be filling adsorbent quality, g.

10. test volatile organic matter adsorbance and the method for desorption quantity as claimed in claim 7, it is characterised in that described Breakthrough concentration be when in tail gas content of organics be content of organics in unstripped gas 5% be breakthrough concentration.