Comprehensive treatment system for VOCs in cyclohexanone tail gas

Abstract

The utility model relates to the technical field of tail gas treatment, in particular to a comprehensive treatment system for VOCs (Volatile Organic Compounds) in cyclohexanone tail gas. The system comprises a reactor, a gas heat exchanger, a heater and a waste heat exchanger, an inlet of the reactor is connected with a cyclohexanone tail gas source and an outlet of the heater, and an outlet is connected with a bottom inlet of the gas heat exchanger; a top inlet of the gas heat exchanger is connected with a cyclohexanone tail gas source, a top outlet is connected with an inlet of the heater, and a bottom outlet is connected with a first inlet of the waste heat exchanger; a second inlet of the waste heat exchanger is connected with a boiler water pipeline, a first outlet is used for discharging low-pressure steam, and a second outlet is used for discharging gas after heat exchange; and a regulating valve is arranged between the inlet of the reactor and the cyclohexanone tail gas source and is in signal connection with the automatic control unit. The tail gas treatment device effectively solves the technical problem of low energy utilization rate caused by the fact that a tail gas treatment device in the prior art cannot collect and utilize heat released by catalytic oxidation reaction.

Description

Technical Field

[0001] This utility model relates to the field of exhaust gas treatment technology, and in particular to a comprehensive treatment system for VOCs in cyclohexanone exhaust gas. Background Technology

[0002] Cyclohexanone is a saturated ketone compound with a six-membered ring structure. The production of cyclohexanone easily generates tail gases, which contain 97 vol% N2, 3 vol% O2, 0.5 vol% CO2 / CO, and 0.09 vol% cyclohexane, cyclohexanone, and cyclohexanol. In addition, it contains substances at a concentration of 400 mg / Nm³. 3 The exhaust gases are C1-C5 hydrocarbons. These gases, containing cyclohexane, cyclohexanone, and cyclohexanol, will not only harm the environment if directly released into the environment, but also endanger human health. Therefore, cyclohexanone exhaust gases need to be treated using exhaust gas treatment devices before being emitted.

[0003] For example, patent document CN219002552U discloses a cyclohexanone production tail gas treatment device. This device includes a housing, within which are a first heating chamber, a first catalytic oxidation chamber, a second heating chamber, and a second catalytic oxidation chamber. The housing has an inlet pipe communicating with the first heating chamber and an outlet pipe communicating with the second catalytic oxidation chamber. Each inlet and outlet pipe is equipped with a shut-off valve. The first heating chamber and the first catalytic oxidation chamber are connected via a first connecting pipe, the first catalytic oxidation chamber and the second heating chamber are connected via a second connecting pipe, and the second heating chamber and the second catalytic oxidation chamber are connected via a third connecting pipe. In use, the cyclohexanone tail gas enters the housing through the inlet pipe and sequentially passes through the first heating chamber, the first catalytic oxidation chamber, the second heating chamber, and the second catalytic oxidation chamber before exiting through the outlet pipe.

[0004] As can be seen, the above-mentioned device first heats the cyclohexanone tail gas through a heating chamber, and then sends the heated cyclohexanone tail gas into a catalytic oxidation chamber for reaction, thereby ensuring the reaction effect of catalytic oxidation. However, the cyclohexanone tail gas releases a large amount of heat energy during the catalytic oxidation reaction. The above-mentioned device cannot effectively utilize this released heat, resulting in low energy utilization efficiency and increased operating costs for enterprises. Utility Model Content

[0005] This invention provides a comprehensive VOCs treatment system for cyclohexanone exhaust gas to solve the technical problem that existing exhaust gas treatment devices cannot collect and utilize the heat released by the catalytic oxidation reaction, resulting in low energy utilization.

[0006] To solve the above problems, the cyclohexanone exhaust VOCs comprehensive treatment system provided by this utility model adopts the following technical solution:

[0007] A comprehensive VOCs treatment system for cyclohexanone tail gas includes a reactor, a gas heat exchanger, a heater, and a waste heat exchanger.

[0008] The reactor inlet is connected to the cyclohexanone tail gas source and the heater outlet, and its outlet is connected to the bottom inlet of the gas heat exchanger.

[0009] The top inlet of the gas heat exchanger is connected to the cyclohexanone tail gas source, its top outlet is connected to the inlet of the heater, and its bottom outlet is connected to the first inlet of the waste heat heat exchanger.

[0010] The second inlet of the waste heat exchanger is connected to the boiler water pipe, and its first outlet is used to discharge low-pressure steam and its second outlet is used to discharge the gas after heat exchange.

[0011] A regulating valve is installed between the reactor inlet and the cyclohexanone tail gas source. The regulating valve is connected to an automated control unit to adjust the valve opening according to the temperature inside the reactor, thereby regulating the flow rate of cyclohexanone tail gas entering the reactor.

[0012] The beneficial effects of the cyclohexanone tail gas VOCs comprehensive treatment system provided by this utility model are as follows: By setting up a gas heat exchanger, the top inlet of the gas heat exchanger is connected to the cyclohexanone tail gas source, the bottom inlet is connected to the reactor outlet, the top outlet is connected to the heater inlet, and the bottom outlet is connected to the first inlet of the waste heat exchanger. In the initial stage of heating, the cyclohexanone tail gas from the gas heat exchanger can be heated by an electric heater to ensure that the temperature in the reactor meets the reaction requirements. The high-temperature gas obtained after the reactor reaction passes through the gas heat exchanger and the waste heat exchanger in sequence. In the gas heat exchanger, the high-temperature gas heats the cyclohexanone tail gas in the gas heat exchanger, realizing the initial utilization of the high-temperature gas waste heat. In the waste heat exchanger, the high-temperature gas exchanges heat with the boiler water in the waste heat exchanger, realizing the secondary utilization of the high-temperature gas waste heat.

[0013] Through the above-mentioned design, this utility model effectively solves the technical problem in the prior art that exhaust gas treatment devices cannot collect and utilize the heat released by catalytic oxidation reaction, resulting in low energy utilization.

[0014] Furthermore, the automation control unit includes a temperature sensor installed inside the reactor, an actuator that drives the regulating valve, and a controller that is signal-connected to the temperature sensor and the actuator.

[0015] Furthermore, the reactor contains a gas distribution layer and a catalyst bed arranged sequentially from top to bottom.

[0016] Furthermore, the gas distribution layer includes a plurality of uniformly distributed gas distributors.

[0017] Furthermore, the catalyst bed is provided with a honeycomb-shaped oxidative decomposition catalyst.

[0018] Furthermore, both the gas heat exchanger and the waste heat heat exchanger are shell-and-tube heat exchangers.

[0019] Furthermore, the shell side of the gas heat exchanger is uniformly distributed with semi-baffles.

[0020] Furthermore, the outlet of the waste heat exchanger is connected to a vent chimney.

[0021] Furthermore, the regulating valve is a pneumatic butterfly valve.

[0022] Furthermore, the heater is an electric heater. Attached Figure Description

[0023] The above and other objects, features, and advantages of the present invention will become readily understood by reading the following detailed description of exemplary embodiments with reference to the accompanying drawings. In the drawings, several embodiments of the present invention are shown by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein:

[0024] Figure 1 This is a schematic diagram of the cyclohexanone tail gas VOCs comprehensive treatment system provided by this utility model.

[0025] Explanation of reference numerals in the attached figures:

[0026] 1. Reactor; 2. Gas heat exchanger; 3. Heater; 4. Waste heat exchanger; 5. Control valve; 6. Vent chimney. Detailed Implementation

[0027] The principles and spirit of this utility model will be explained in detail below with reference to several representative embodiments.

[0028] An embodiment of the cyclohexanone exhaust VOCs comprehensive treatment system provided by this utility model:

[0029] like Figure 1 As shown, the cyclohexanone tail gas VOCs comprehensive treatment system includes reactor 1, gas heat exchanger 2, heater 3, and waste heat heat exchanger 4.

[0030] The reactor 1 has its inlet connected to the cyclohexanone tail gas source and the outlet of the heater 3, and its outlet connected to the bottom inlet of the gas heat exchanger 2. The gas heat exchanger 2 has its top inlet connected to the cyclohexanone tail gas source, its top outlet connected to the inlet of the heater 3, and its bottom outlet connected to the first inlet of the waste heat exchanger 4. The waste heat exchanger 4 has its second inlet connected to the boiler water pipe, its first outlet for discharging steam, and its second outlet for discharging the heat-exchanged gas.

[0031] In this embodiment, a gas distribution layer and a catalyst bed are arranged sequentially from top to bottom inside the reactor 1. The gas distribution layer includes multiple uniformly distributed gas distributors, and the catalyst bed is provided with a honeycomb-shaped oxidation decomposition catalyst. In other embodiments, multiple gas distribution layers and multiple catalyst beds are arranged sequentially from top to bottom inside the reactor 1, and the multiple gas distribution layers and multiple catalyst beds are spaced apart in the vertical direction.

[0032] In this embodiment, both the gas heat exchanger 2 and the waste heat heat exchanger 4 are shell and tube heat exchangers. The shell side of the gas heat exchanger 2 is evenly distributed with semi-baffles, and the outlet of the waste heat heat exchanger 4 is connected to a venting chimney 6. In other embodiments, the waste heat heat exchanger 4 is a waste heat boiler.

[0033] In this embodiment, heater 3 is an electric heater; in other embodiments, heater 3 may be a steam-gas heat exchanger.

[0034] In addition, a regulating valve 5 is installed between the inlet of reactor 1 and the cyclohexanone tail gas source. The regulating valve 5 is connected to the signal of the automatic control unit (not shown in the figure) so as to adjust the opening of the regulating valve 5 according to the temperature in reactor 1, thereby adjusting the gas flow rate of cyclohexanone tail gas entering reactor 1.

[0035] Specifically, the automation control unit includes a temperature sensor installed in the reactor 1, an actuator that drives the regulating valve 5, and a controller that is connected to the temperature sensor and the actuator via signals.

[0036] In this embodiment, the regulating valve 5 is a pneumatic butterfly valve.

[0037] It should be noted that VOCs is an abbreviation for Volatile Organic Compounds.

[0038] The working principle of the cyclohexanone exhaust VOCs comprehensive treatment system provided by this utility model is as follows:

[0039] First, during the initial operation of the cyclohexanone tail gas VOCs integrated treatment system, cyclohexanone tail gas from the cyclohexanone tail gas source enters reactor 1 and gas heat exchanger 2 through the inlet and the bottom inlet of gas heat exchanger 2. Then, the cyclohexanone tail gas in gas heat exchanger 2 enters heater 3 through its top outlet for heating, and is then transported back to reactor 1 to undergo catalytic oxidation with the catalyst bed along with the cyclohexanone tail gas in reactor 1. The high-temperature gas obtained from the catalytic oxidation has a temperature of 550℃, and this high-temperature gas enters gas heat exchanger 2 through the top inlet. After exchanging heat with the cyclohexanone tail gas in the gas heat exchanger 2, the gas exits from the bottom outlet of the gas heat exchanger 2 and enters the waste heat exchanger 4, where it exchanges heat with the boiler water in the waste heat exchanger 4. The temperature at the bottom outlet of the gas heat exchanger 2 is about 300°C. The high-temperature gas from the gas heat exchanger 2 exchanges heat with the superheated demineralized water that enters the shell side of the waste heat exchanger 4, and heats the boiler water in the waste heat exchanger 4 to obtain low-pressure steam and gas at 0.4 MPa. The low-pressure steam exits from the first outlet of the waste heat exchanger 4, and the gas exits from the second outlet of the waste heat exchanger 4.

[0040] During the continuous treatment of cyclohexanone tail gas, the temperature of the cyclohexanone tail gas from the tail gas source is approximately 30°C in the gas heat exchanger 2. It enters the bottom tube of the gas heat exchanger 2 and exchanges heat with the high-temperature gas from reactor 1 to approximately 280°C before entering the heater 3. When the automatic control unit detects that the temperature inside reactor 1 is too high, it increases the opening of the regulating valve 5, allowing more low-temperature cyclohexanone tail gas to directly enter reactor 1, thereby lowering the temperature inside reactor 1. When the automatic control unit detects that the temperature inside reactor 1 is too low, it decreases the opening of the regulating valve 5, allowing more low-temperature cyclohexanone tail gas to enter the gas heat exchanger 2 and, after being heated by the heater 3, enter reactor 1, thus ensuring the inlet temperature of reactor 1.

[0041] Based on the above description in this specification, those skilled in the art will also understand that the following terms used, such as "upper," "lower," "front," "rear," "left," "right," "width," "horizontal," "top," "bottom," "inner," and "outer," are terms indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings of this specification. They are only for the purpose of facilitating the explanation of the present invention and simplifying the description, and do not explicitly or implicitly suggest that the device or element involved must have the specific orientation, or be constructed and operated in a specific orientation. Therefore, the above-mentioned orientation or positional relationship terms should not be understood or interpreted as limitations on the present invention.

[0042] In addition, in the description of this specification, "multiple" means at least two, such as two, three or more, etc., unless otherwise expressly and specifically defined.

Claims

1. A cyclohexanone tail gas VOCs comprehensive treatment system, characterized in that, The device comprises a reactor, a gas heat exchanger, a heater and a waste heat exchanger. The inlet of the reactor is connected with a cyclohexanone tail gas source and the outlet of the heater, and the outlet of the reactor is connected with the bottom inlet of the gas heat exchanger. The top inlet of the gas heat exchanger is connected with a cyclohexanone tail gas source, the top outlet is connected with the inlet of the heater, and the bottom outlet is connected with the first inlet of the waste heat exchanger. The second inlet of the waste heat exchanger is connected with a boiler water pipeline, the first outlet is used for discharging low-pressure steam, and the second outlet is used for discharging the heat-exchanged gas. An adjusting valve is arranged between the inlet of the reactor and the cyclohexanone tail gas source, and the adjusting valve is signal-connected with an automatic control unit, so as to adjust the opening degree of the adjusting valve according to the temperature in the reactor, thereby adjusting the flow of the cyclohexanone tail gas input into the reactor.

2. The cyclohexanone tail gas VOCs comprehensive treatment system according to claim 1, characterized in that, The automatic control unit comprises a temperature sensor installed in the reactor, an actuator driving the adjusting valve, and a controller signal-connected with the temperature sensor and the actuator.

3. The cyclohexanone tail gas VOCs comprehensive treatment system according to claim 1 or 2, characterized in that, A gas distribution layer and a catalyst bed layer are sequentially arranged in the reactor from top to bottom.

4. The cyclohexanone tail gas VOCs comprehensive treatment system according to claim 3, characterized in that, The gas distribution layer comprises a plurality of gas distributors.

5. The cyclohexanone tail gas VOCs comprehensive treatment system according to claim 3, characterized in that, The catalyst bed layer is provided with a honeycomb-shaped oxidative decomposition catalyst.

6. The cyclohexanone tail gas VOCs comprehensive treatment system according to claim 1 or 2, characterized in that, The gas heat exchanger and the waste heat exchanger are both shell-and-tube heat exchangers.

7. The cyclohexanone tail gas VOCs comprehensive treatment system according to claim 6, characterized in that, Half baffles are uniformly arranged in the shell side of the gas heat exchanger.

8. The cyclohexanone tail gas VOCs comprehensive treatment system according to claim 1 or 2, characterized in that, An exhaust stack is connected with the gas outlet of the waste heat exchanger.

9. The cyclohexanone tail gas VOCs comprehensive treatment system according to claim 1 or 2, characterized in that, The adjusting valve is a pneumatic butterfly valve.

10. The cyclohexanone tail gas VOCs comprehensive treatment system according to claim 1 or 2, characterized in that, The heater is an electric heater.

Images