A secondary cooling zeolite rotor catalytic oxidation VOCs treatment system and method

Abstract

The present invention provides a zeolite wheel catalytic oxidation VOCs treatment system and method with secondary cooling. The system includes an adsorption system and a desorption system. The adsorption system includes a zeolite wheel adsorption zone, an adsorption fan, and an exhaust stack arranged in sequence. The desorption system includes a zeolite wheel secondary cooling zone, a zeolite wheel primary cooling zone, a cold stream of a first heat exchanger, a zeolite wheel desorption zone, a desorption fan, a cold stream of a second heat exchanger, a catalytic combustion furnace, a hot stream of a first heat exchanger, a hot stream of a second heat exchanger, and an exhaust stack. The core equipment of the system is a zeolite wheel with secondary cooling. The high-temperature adsorption zone of the zeolite wheel is cooled by two stages, and after being effectively cooled, it enters the adsorption zone to carry out adsorption work. The decrease in temperature can increase the zeolite adsorption capacity, so the system can effectively improve the purification efficiency of the adsorption zone of the zeolite wheel.

Description

Technical Field

[0001] The present invention relates to the technical field of volatile organic waste gas treatment, and particularly to a zeolite wheel catalytic oxidation VOCs treatment system and method with secondary cooling.

Background Art

[0002] VOCs emissions are diverse and complex, and it is difficult for a single VOCs treatment technology to cope with actual industrial VOCs emissions. The zeolite wheel-catalytic oxidation technology is considered an advanced and reliable combined technology in the treatment of VOCs in industries such as painting, coatings, and printing. The zeolite wheel mainly includes an adsorption zone, a desorption zone, and a cooling zone. The adsorption zone is used for VOCs adsorption; the desorption zone is used for zeolite wheel regeneration; the cooling zone is used to cool the zeolite module after high-temperature desorption to prepare for the adsorption operation. Since the cooling zone uses ambient-temperature waste gas for air cooling and the air volume is the same as that of the desorption zone, it is impossible to effectively cool the high-temperature module in the desorption zone to ambient temperature. This will cause the bed layer in the cooling zone to still have a certain temperature when entering the adsorption zone. After the waste gas passes through the adsorption zone, the temperature will increase by 3-5°C, and a high adsorption temperature will lead to a decrease in the adsorption capacity. To strengthen the VOCs adsorption process, reducing the temperature of the zeolite module entering the desorption zone is an effective way. Now, a zeolite wheel catalytic oxidation VOCs treatment system and method with secondary cooling are proposed.

Summary of the Invention

[0003] The purpose of the present invention is to solve the problems in the prior art, and propose a zeolite wheel catalytic oxidation VOCs treatment system and method with secondary cooling, which uses multi-stage cooling to solve the problem of excessive temperature of the zeolite wheel module after entering the adsorption zone and strengthen the adsorption process.

[0004] To achieve the above purpose, the present invention proposes a zeolite wheel catalytic oxidation VOCs treatment system with secondary cooling, including a zeolite wheel, an adsorption fan, an exhaust stack, a desorption fan, a catalytic combustion furnace, a first heat exchanger, and a second heat exchanger. An adsorption zone, a desorption zone, a primary cooling zone, and a secondary cooling zone are circumferentially arranged in sequence on the zeolite wheel. The outlet of the adsorption zone of the zeolite wheel is connected to the inlet of the adsorption fan, the outlet of the adsorption fan is connected to the exhaust stack, the outlet of the secondary cooling zone of the zeolite wheel is connected to the inlet of the primary cooling zone, the outlet of the primary cooling zone of the zeolite wheel is connected to the cold fluid inlet of the first heat exchanger, the cold fluid outlet of the first heat exchanger is connected to the inlet of the desorption zone of the zeolite wheel, the outlet of the desorption zone of the zeolite wheel is connected to the inlet of the desorption fan, the outlet of the desorption fan is connected to the cold fluid inlet of the second heat exchanger, the cold fluid outlet of the second heat exchanger is connected to the inlet of the catalytic combustion furnace, the outlet of the catalytic combustion furnace is connected to the hot fluid inlet of the first heat exchanger, the hot fluid outlet of the first heat exchanger is connected to the hot fluid inlet of the second heat exchanger, and the hot fluid outlet of the second heat exchanger is connected to the exhaust stack.

[0005] Preferably, the zeolite rotary wheel is controlled to rotate unidirectionally so that the same sector area inside it passes through the adsorption zone, the desorption zone, the primary cooling zone, and the secondary cooling zone one by one, and the four processes of normal temperature adsorption concentration, high temperature desorption regeneration, high temperature primary cooling, and secondary cooling to normal temperature are carried out in sequence.

[0006] Preferably, the catalytic combustion furnace is used to purify the high-concentration VOCs waste gas generated by desorption through catalytic oxidation, and includes a heating system and a catalyst bed layer arranged in sequence along the waste gas treatment direction.

[0007] The present invention also proposes a method for treating VOCs by catalytic oxidation of a zeolite rotary wheel with secondary cooling, which includes the following steps:

[0008] S1. Adsorption process: The waste gas first enters the adsorption zone of the zeolite rotary wheel for adsorption purification, and then is drawn by an adsorption fan and enters the exhaust stack for emission;

[0009] S2. Desorption process: The waste gas first enters the secondary cooling zone of the zeolite rotary wheel for primary preheating, then enters the primary cooling zone of the zeolite rotary wheel for secondary preheating, then enters the cold flow pipeline of the first heat exchanger to be heated to the desorption temperature, and then enters the desorption zone of the zeolite rotary wheel to complete the desorption operation, enriching into a high-concentration VOCs waste gas. Subsequently, it is transported by a desorption fan, enters the cold flow of the second heat exchanger for preheating, and then enters the catalytic combustion furnace for oxidation purification. Subsequently, it successively passes through the hot flow pipelines of the first heat exchanger and the second heat exchanger to heat the waste gas at the inlet of the desorption zone of the zeolite rotary wheel and the waste gas at the inlet of the catalytic combustion furnace respectively, and finally enters the exhaust stack for emission.

[0010] Preferably, the zeolite rotary wheel rotates unidirectionally, so that after the desorption zone is desorbed at high temperature, it is cooled sequentially through the primary cooling zone and the secondary cooling zone, and finally enters the adsorption zone for adsorption work.

[0011] Preferably, in step S1 and step S2, the waste gas treated by dust removal and drying enters the adsorption zone and the secondary cooling zone of the zeolite rotary wheel for adsorption and desorption respectively at a ratio of 8:1 to 20:1.

[0012] Preferably, in step S2, after the waste gas is preheated twice through the secondary cooling zone and the primary cooling zone of the zeolite rotary wheel, it enters the cold flow pipeline of the first heat exchanger and is heated to the desorption temperature of 180 - 220 °C.

[0013] The beneficial effects of the present invention:

[0014] 1. Reduce the temperature of the adsorption zone module of the zeolite rotary wheel, strengthen the adsorption process, and increase the purification efficiency of VOCs.

[0015] 2. Reasonably utilize the waste heat of the zeolite module in the desorption zone of the zeolite rotary wheel and reduce energy waste.

[0016] 3. The designed heat exchange capacity of the first heat exchanger required to reach the same desorption temperature is reduced, the heat exchange area is reduced, and the equipment volume is reduced.

[0017] 4. The outlet temperature of the hot flow of the first heat exchanger increases, and the waste heat resources increase.

[0018] The features and advantages of the present invention will be described in detail through embodiments in conjunction with the accompanying drawings.

Description of the Drawings

[0019] Figure 1 is a schematic diagram of a zeolite wheel catalytic oxidation VOC treatment system with secondary cooling according to the present invention;

[0020] Figure 2 is a schematic diagram of a zeolite wheel with secondary cooling, used to illustrate the functional area division and operation mode of the zeolite wheel.

[0021] Description of the reference numerals:

[0022] 1 - zeolite wheel, 101 - adsorption zone, 102 - secondary cooling zone, 103 - primary cooling zone, 104 - desorption zone, 2 - adsorption fan, 3 - exhaust stack, 4 - desorption fan, 5 - catalytic combustion furnace, 6 - first heat exchanger, 7 - second heat exchanger.

Detailed Embodiments

[0023] A zeolite wheel catalytic oxidation VOC treatment system with secondary cooling according to the present invention, by adopting a zeolite wheel with secondary cooling, fully cools the zeolite module in the desorption zone of the zeolite wheel, strengthens the adsorption process, and achieves the purpose of increasing the purification efficiency; at the same time, utilizes the desorption waste heat to effectively preheat the desorption waste gas. The specific implementation method is as follows:

[0024] Refer to Figure 1 , the zeolite wheel catalytic oxidation VOC treatment system with secondary cooling includes an adsorption system and a desorption system, and the core equipment is a zeolite wheel 1 provided with secondary cooling.

[0025] Refer to Figure 2 , on the zeolite wheel 1, an adsorption zone 101, a desorption zone 104, a primary cooling zone 103, and a secondary cooling zone 102 are arranged circumferentially in sequence. The working module (wheel) of the zeolite wheel 1 controls the same fan-shaped area inside it to pass through the adsorption zone 101, the desorption zone 104, the primary cooling zone 103, and the secondary cooling zone 102 one by one through one-way rotation, and successively undergoes four processes of normal-temperature adsorption concentration, high-temperature desorption regeneration, high-temperature primary cooling, and secondary cooling to normal temperature, completing the adsorption-desorption regeneration process.

[0026] Refer to Figures 1 to 2, in this embodiment, the system includes a zeolite rotor 1, an adsorption fan 2, an exhaust stack 3, a desorption fan 4, a catalytic combustion furnace 5, a first heat exchanger 6 and a second heat exchanger 7. The outlet of the adsorption zone 101 of the zeolite rotor 1 is connected to the inlet of the adsorption fan 2. The outlet of the adsorption fan 2 is connected to the exhaust stack 3. The outlet of the secondary cooling zone 102 of the zeolite rotor 1 is connected to the inlet of the primary cooling zone 103. The outlet of the primary cooling zone 103 of the zeolite rotor 1 is connected to the cold fluid inlet of the first heat exchanger 6. The cold fluid outlet of the first heat exchanger 6 is connected to the inlet of the desorption zone 104 of the zeolite rotor 1. The outlet of the desorption zone 104 of the zeolite rotor 1 is connected to the inlet of the desorption fan 4. The outlet of the desorption fan 4 is connected to the cold fluid inlet of the second heat exchanger 7. The cold fluid outlet of the second heat exchanger 7 is connected to the inlet of the catalytic combustion furnace 5. The outlet of the catalytic combustion furnace 5 is connected to the hot fluid inlet of the first heat exchanger 6. The hot fluid outlet of the first heat exchanger 6 is connected to the hot fluid inlet of the second heat exchanger 7. The hot fluid outlet of the second heat exchanger 7 is connected to the exhaust stack 3.

[0027] A method for treating VOCs by catalytic oxidation of a zeolite rotor with secondary cooling includes the following steps:

[0028] S0. The dust-removed and dried waste gas enters the adsorption zone 101 of the zeolite rotor in the adsorption system and the secondary cooling zone 102 of the zeolite rotor in the desorption system at a ratio of 8:1 to 20:1 (preferably 9:1).

[0029] S1. Adsorption process: The waste gas first enters the adsorption zone 101 of the zeolite rotor 1 for adsorption purification, and then is drawn by the adsorption fan 2 and enters the exhaust stack 3 for discharge.

[0030] S2. Desorption process: The waste gas first enters the secondary cooling zone 102 of the zeolite rotor 1 for primary preheating, then enters the primary cooling zone 103 of the zeolite rotor 1 for secondary preheating, and then enters the cold fluid pipeline of the first heat exchanger 6 to be heated to the desorption temperature of 180 - 220 °C, and then enters the desorption zone 104 of the zeolite rotor 1 to complete the desorption operation, and is enriched into high-concentration VOCs waste gas. Subsequently, it is transported by the desorption fan 4, enters the cold fluid of the second heat exchanger 7 for preheating, and then enters the catalytic combustion furnace 5 for oxidation purification. Subsequently, it successively passes through the hot fluid pipelines of the first heat exchanger 6 and the second heat exchanger 7 to heat the waste gas at the inlet of the desorption zone 104 of the zeolite rotor 1 and the waste gas at the inlet of the catalytic combustion furnace 5 respectively, and finally enters the exhaust stack 3 for discharge.

[0031] Furthermore, the zeolite rotor 1 rotates unidirectionally, so that after the desorption zone 104 is desorbed at high temperature, it is cooled successively through the primary cooling zone 103 and the secondary cooling zone 102, and finally enters the adsorption zone 101 for adsorption work.

[0032] Further, the catalytic combustion furnace 5 is used to purify the high-concentration VOCs waste gas generated by desorption through catalytic oxidation, and includes a heating system and a catalyst bed layer arranged in sequence along the waste gas treatment direction.

[0033] The above embodiments are illustrative of the present invention and not restrictive thereof. Any solution obtained by simply transforming the present invention falls within the protection scope of the present invention.

Claims

1. A method for treating VOCs by catalytic oxidation of a zeolite rotor with secondary cooling, characterized in that: A two-stage cooling zeolite wheel catalytic oxidation VOC treatment system is adopted. The zeolite wheel catalytic oxidation VOC treatment system includes a zeolite wheel (1), an adsorption fan (2), an exhaust stack (3), a desorption fan (4), a catalytic combustion furnace (5), a first heat exchanger (6) and a second heat exchanger (7). An adsorption zone (101), a desorption zone (104), a primary cooling zone (103), and a secondary cooling zone (102) are arranged circumferentially and sequentially on the zeolite wheel (1). The outlet of the adsorption zone (101) of the zeolite wheel (1) is connected to the inlet of the adsorption fan (2), the outlet of the adsorption fan (2) is connected to the exhaust stack (3), the outlet of the secondary cooling zone (102) of the zeolite wheel (1) is connected to the inlet of the primary cooling zone (103), the outlet of the primary cooling zone (103) of the zeolite wheel (1) is connected to the cold fluid inlet of the first heat exchanger (6), the cold fluid outlet of the first heat exchanger (6) is connected to the inlet of the desorption zone (104) of the zeolite wheel (1), the outlet of the desorption zone (104) of the zeolite wheel (1) is connected to the inlet of the desorption fan (4), the outlet of the desorption fan (4) is connected to the cold fluid inlet of the second heat exchanger (7), the cold fluid outlet of the second heat exchanger (7) is connected to the inlet of the catalytic combustion furnace (5), the outlet of the catalytic combustion furnace (5) is connected to the hot fluid inlet of the first heat exchanger (6), the hot fluid outlet of the first heat exchanger (6) is connected to the hot fluid inlet of the second heat exchanger (7), and the hot fluid outlet of the second heat exchanger (7) is connected to the exhaust stack (3); The zeolite wheel (1) is controlled to rotate unidirectionally so that the same fan-shaped area inside it passes through the adsorption zone (101), the desorption zone (104), the primary cooling zone (103), and the secondary cooling zone (102) one by one, and four processes of normal temperature adsorption and concentration, high temperature desorption and regeneration, high temperature primary cooling, and secondary cooling to normal temperature are carried out in sequence; The catalytic combustion furnace (5) is used to purify the high-concentration VOC waste gas generated by desorption through catalytic oxidation, and includes a heating system and a catalyst bed layer arranged sequentially along the waste gas treatment direction; The zeolite wheel catalytic oxidation VOC treatment method includes the following steps: S1. Adsorption process: The waste gas first enters the adsorption zone (101) of the zeolite wheel (1) for adsorption and purification, and then is drawn by the adsorption fan (2) and enters the exhaust stack (3) for discharge; S2. Desorption process: The waste gas first enters the secondary cooling zone (102) of the zeolite rotor (1) for primary preheating, then enters the primary cooling zone (103) of the zeolite rotor (1) for secondary preheating, and then enters the cold flow pipeline of the first heat exchanger (6) to be heated to the desorption temperature. After that, it enters the desorption zone (104) of the zeolite rotor (1) to complete the desorption operation and be enriched into high-concentration VOCs waste gas. Subsequently, it is transported by the desorption fan (4), enters the cold flow of the second heat exchanger (7) for preheating, and then enters the catalytic combustion furnace (5) for oxidation purification. Subsequently, it successively passes through the hot flow pipelines of the first heat exchanger (6) and the second heat exchanger (7) to heat the waste gas at the inlet of the desorption zone (104) of the zeolite rotor (1) and the waste gas at the inlet of the catalytic combustion furnace (5) respectively. Finally, it enters the exhaust stack (3) for emission.

2. The method for treating VOCs by catalytic oxidation of a zeolite rotor with secondary cooling according to claim 1, characterized in that: The zeolite rotor (1) rotates unidirectionally, so that after the desorption zone (104) undergoes high-temperature desorption, it is cooled successively through the primary cooling zone (103) and the secondary cooling zone (102), and finally enters the adsorption zone (101) for adsorption work.

3. The method for treating VOCs by catalytic oxidation of a zeolite rotor with secondary cooling according to claim 1, characterized in that: In step S1 and step S2, the waste gas that has been dust-removed and dried enters the adsorption zone (101) of the zeolite rotor (1) and the secondary cooling zone (102) of the zeolite rotor (1) for adsorption and desorption respectively at a ratio of 8:1 to 20:

1.

4. The method for treating VOCs by catalytic oxidation of a zeolite rotor with secondary cooling according to claim 1, characterized in that: In step S2, after the waste gas is subjected to secondary preheating through the secondary cooling zone (102) and the primary cooling zone (103) of the zeolite rotor (1), it enters the cold flow pipeline of the first heat exchanger (6) and is heated to the desorption temperature of 180 - 220 °C.

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