CN110848713A

CN110848713A - Exhaust gas treatment system

Info

Publication number: CN110848713A
Application number: CN201911094410.6A
Authority: CN
Inventors: 张家骥
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-11-11
Filing date: 2019-11-11
Publication date: 2020-02-28

Abstract

The invention discloses a waste gas treatment system, which comprises a heat exchanger, a heat storage chamber and a combustion chamber, wherein the heat exchanger is provided with a first channel and a second channel which are separated, the heat storage chamber is internally provided with a heat storage structure, the heat storage structure is provided with a pore passage, the combustion chamber is internally provided with a partition wall, the partition wall divides an inner cavity of the combustion chamber into a first cavity and a second cavity, the flow area of the first cavity is smaller than that of the second cavity, the right side of the first cavity is communicated with the outlet end of the first channel, the right side of the second cavity is communicated with the inlet end of the second channel through the pore passage on the heat storage structure, the partition wall is provided with a backflow through hole, and the second cavity is internally provided. Gas in the second cavity can pass the backward flow through-hole and flow to first cavity, and gas can circulate in the combustion chamber, prolongs gaseous dwell time in the combustion chamber to make more VOCs waste gas can decompose, improve the decomposition rate of VOCs waste gas, optimize the treatment effect of VOCs waste gas.

Description

Exhaust gas treatment system

Technical Field

The invention relates to an environment-friendly treatment device, in particular to an exhaust gas treatment system.

Background

VOCs refers to volatile organic compounds, and in some production processes, waste gases of VOCs harmful to the environment are generated and can be discharged into the atmosphere after being treated. Two types of VOCs exhaust treatment devices are common: direct-fired exhaust gas treatment furnaces and regenerative exhaust gas treatment furnaces.

The direct-fired waste gas treatment stove sends the VOCs waste gas into the combustion chamber, through combustor burning fuel, under the flame high temperature effect for VOCs waste gas converts harmless material into, and discharges through exhaust duct. In order to recover heat, some direct-fired waste gas treatment furnaces are also provided with a heat exchanger, and heat exchange is carried out on the treated high-temperature gas and the VOCs waste gas to be treated through the heat exchanger, so that the VOCs waste gas to be treated enters a combustion chamber after being heated. The direct-fired waste gas treatment furnace has simple structure and low cost, but the heat exchanger belongs to indirect heat exchange, so the heat exchange efficiency is not high.

The heat accumulating type waste gas treatment furnace adopts a double-tower structure and comprises two parallel heat accumulating chambers, and a heat accumulating structure is arranged in each heat accumulating chamber. One side of the two regenerators is communicated with the combustion chamber. When the device operates, VOCs waste gas enters a regenerator first, the heat storage structure of the regenerator has the heat recovered by last circulation, the VOCs waste gas is preheated and then enters the combustion chamber and is oxidized and decomposed into harmless substances in the combustion chamber, the treated high-temperature gas passes through another regenerator, the heat is recovered by the heat storage structure of the other regenerator, and the gas after heat recovery is discharged into the environment. When advancing VOCs waste gas next time, need switch the route of admitting air, VOCs waste gas gets into earlier and carries out the heat exchange and preheat in the regenerator through the heat accumulation, then gets into the combustion chamber again and carries out oxidative decomposition, and the high temperature gas after the processing carries out heat recovery through another regenerator, discharges at last. So, two regenerators carry out heat accumulation and heat recovery in turn, get into two regenerators in turn and preheat during VOCs waste gas feeding. Because two regenerators are introduced, the heat storage structure in the regenerators and gas exchange directly, the heat exchange effect is good, and the overall energy consumption is low. However, since the flow path of the gas needs to be switched, there are many gas lines, many control valves, complicated control methods, high cost, and troublesome post-maintenance.

There are also some exhaust gas treatment systems combining the above two exhaust gas treatment furnace structures, and the exhaust gas treatment systems can combine the advantages of the two exhaust gas treatment furnaces. In this exhaust-gas treatment system, be provided with heat accumulation structure and heat exchanger simultaneously, VOCs waste gas passes and gets into in the combustion chamber and decomposes behind the heat exchanger, and the high temperature gas after the decomposition passes behind heat accumulation structure and the heat exchanger and discharges. However, in actual use, in some cases, the temperature of the VOCs waste gas after passing through the heat exchanger and the heat storage structure is difficult to reach the lowest temperature at which the VOCs waste gas can be decomposed, and the VOCs waste gas needs to be further heated in the combustion chamber to reach the decomposition temperature. In addition, the dwell time of VOCs waste gas in the combustion chamber after reaching the decomposition temperature is limited, can lead to some VOCs waste gas just being discharged the combustion chamber before not decomposing to can reduce the treatment effeciency of VOCs waste gas, the treatment effect of VOCs waste gas is not good.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art and to providing an exhaust gas treatment system capable of optimizing the treatment effect of VOCs exhaust gas.

The scheme adopted by the invention is as follows: an exhaust gas treatment system comprising

A heat exchanger having first and second passages separated by a heat exchange wall thereon;

the regenerative chamber is internally provided with a heat storage structure, and the heat storage structure is provided with a pore passage through which air flow can pass;

the combustor is internally provided with a partition wall, the partition wall divides an inner cavity of the combustor into a first chamber and a second chamber, a space is reserved between the left side wall of the partition wall and the inner wall of the combustor, the flow area of the first chamber is smaller than that of the second chamber, the right side of the first chamber is communicated with the outlet end of the first channel, and the right side of the second chamber is communicated with the inlet end of the second channel through a pore passage in the heat storage structure;

and a backflow through hole is formed in the partition wall, and a combustor is arranged in the second cavity.

According to the waste gas treatment system, the combustion chamber is internally provided with the airflow boosting device.

According to the exhaust gas treatment system of the present invention, the flow area of the return through hole is gradually reduced from bottom to top.

According to the waste gas treatment system, the airflow boosting device comprises a fan blade, a transmission shaft and a first driving structure, the fan blade is arranged in the second cavity and is positioned below the backflow through hole, one end of the transmission shaft is connected with the fan blade, the other end of the transmission shaft extends out of the combustion chamber, and the other end of the transmission shaft is connected with the first driving structure.

According to the waste gas treatment system, the limit bearing is arranged in the combustion chamber, and the transmission shaft penetrates through the limit bearing.

According to the exhaust gas treatment system, the baffle wall is provided with a stop at the bottom, and the stop is positioned at the right side of the lower end opening of the backflow through hole.

According to the exhaust gas treatment system, the airflow boosting device comprises a flow baffle plate and a second driving structure connected with the flow baffle plate, the bottom of the flow baffle plate is arranged in the first cavity, the flow baffle plate is positioned above the backflow through hole, and the second driving structure can drive the flow baffle plate to lift.

According to the exhaust gas treatment system of the present invention, the bottom surface of the flow baffle is arc-shaped.

The waste gas treatment system further comprises an air inlet pipeline, an exhaust pipeline, a backflow pipeline and a backflow fan arranged on the backflow pipeline, wherein the air inlet pipeline is communicated with the inlet end of the first channel, the exhaust pipeline is communicated with the outlet end of the second channel, the inlet end of the backflow pipeline is communicated with the exhaust pipeline, and the outlet end of the backflow pipeline is communicated with the air inlet pipeline or the inlet end of the first channel.

The waste gas treatment system further comprises an air inlet pipeline, a diversion pipeline and a diversion fan arranged on the diversion pipeline, wherein the air inlet pipeline is communicated with the inlet end of the first channel, the inlet end of the diversion pipeline is communicated with the air inlet pipeline, and the outlet end of the diversion pipeline is communicated with the first chamber.

The scheme has at least one of the following beneficial effects: through the structure, the gas velocity in the first cavity is greater than the gas velocity in the second cavity, make the atmospheric pressure of backward flow through-hole upper end opening part be less than the atmospheric pressure of backward flow through-hole lower extreme opening part, under the effect of atmospheric pressure difference, gas in the second cavity can pass the backward flow through-hole and flow to the first cavity in, gas can circulate in the combustion chamber, can prolong the dwell time of gas in the combustion chamber, so that more VOCs waste gas can decompose, the decomposition rate of VOCs waste gas is improved, the treatment effect of VOCs waste gas is optimized.

Drawings

The invention is further described below with reference to the accompanying drawings and examples;

FIG. 1 is a block diagram of an embodiment of the present invention;

fig. 2 is a block diagram of another embodiment of the present invention.

Detailed Description

Reference will now be made in detail to the present preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.

In the description of the present invention, it should be understood that the orientation or positional relationship referred to in the description of the orientation, such as the upper, lower, front, rear, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the description of the present invention, the meaning of a plurality of means is one or more, the meaning of a plurality of means is two or more, and larger, smaller, larger, etc. are understood as excluding the number, and larger, smaller, inner, etc. are understood as including the number. If the first and second are described for the purpose of distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.

In the description of the present invention, unless otherwise explicitly limited, terms such as arrangement, installation, connection and the like should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific contents of the technical solutions.

Referring to fig. 1 and 2, an exhaust gas treatment system according to an embodiment of the present invention includes a heat exchanger 10, a regenerator 20, a combustion chamber 30, an intake duct 41, and an exhaust duct 42.

The heat exchanger 10 has a first passage 11 and a second passage 12 separated by a heat exchange wall 13, an inlet pipe 41 communicating with an inlet end of the first passage 11, and an outlet pipe 42 communicating with an outlet end of the second passage 12. The heat accumulation chamber 20 is provided with a heat accumulation structure 21, and the heat accumulation structure 21 is provided with a pore passage through which air flow can pass. A partition wall 31 is arranged in the combustion chamber 30, the partition wall 31 divides the inner cavity of the combustion chamber 30 into a first chamber 32 and a second chamber 33, a space is formed between the left side wall of the partition wall 31 and the inner wall of the combustion chamber 30, so that the left side of the first chamber 32 is communicated with the left side of the second chamber 33, the right side of the first chamber 32 is communicated with the outlet end of the first channel 11, the right side of the second chamber 33 is communicated with the inlet end of the second channel 12 through a pore passage on the heat storage structure 21, a backflow through hole 311 is arranged on the partition wall 31, and a combustor 34 is arranged in the second chamber 33. The flow area of the first chamber 32 is smaller than the flow area of the second chamber 33.

One way of operating an exhaust treatment system is as follows:

preheating: combusting the fuel in the second chamber 33 by the burner 34, the exhaust gas resulting from the combustion passing through the heat storage structure 21 and the heat exchanger 10 to warm the heat storage structure 21 and the heat exchanger 10;

waste gas treatment: VOCs waste gas to be treated sequentially passes through the gas inlet pipeline 41 and the first channel 11 to enter the combustion chamber 30, the VOCs waste gas absorbs heat in the heat exchanger 10 to enable the temperature of the VOCs waste gas to rise, the VOCs waste gas is decomposed in the combustion chamber 30 and releases heat at the same time, high-temperature gas after decomposition passes through the heat storage structure 21, the second channel 12 and the exhaust pipeline 42 and is discharged, and the high-temperature gas releases heat in the heat storage structure 21 and the heat exchanger 10.

In the automatic heat balance state, the VOCs waste gas to be treated can absorb enough heat in the heat exchanger 10 and the combustion chamber 30 to reach the decomposable temperature of the VOCs waste gas, and the treated high-temperature gas can also emit enough heat in the heat accumulation structure 21 and the heat exchanger 10, and at this time, the burner 34 does not need to be started. When the VOCs exhaust gas fails to absorb enough heat in heat exchanger 10 and combustor 30 to allow the VOCs exhaust gas to reach a decomposable temperature, burner 34 may be operated to burn fuel to assist in raising the temperature of the VOCs exhaust gas. The heat accumulation structure 21 may release heat to the combustion chamber 30 and the heat exchanger 10, increasing the temperature thereof.

For the exhaust gas treatment system of the present invention, since the flow area of the first chamber 32 is smaller than the flow area of the second chamber 33, the flow rate of the gas in the first chamber 32 is greater than the flow rate of the gas in the second chamber 33, so that the gas pressure at the upper end opening of the backflow through hole 311 is smaller than the gas pressure at the lower end opening of the backflow through hole 311, and the gas in the second chamber 33 can flow into the first chamber 32 through the backflow through hole 311 under the effect of the gas pressure difference.

During operation, VOCs exhaust gas entering the first chamber 32 flows around the partition wall 31 to the second chamber 33. The VOCs exhaust may decompose and release heat in the second chamber 33, and the burner 34 may also release heat during operation, such that the gas temperature in the second chamber 33 may be higher than the gas temperature in the first chamber 32. High-temperature gas in the second chamber 33 can flow to first chamber 32 via return flow channel to the VOCs waste gas that flows in first chamber 32 heaies up, so that it reaches or is close the minimum decomposition temperature of VOCs waste gas, both can decompose after so that VOCs waste gas rapid heating up, improve the decomposition rate of VOCs waste gas, still reducible fuel's use, in order to reduce the energy consumption. In addition, the circulation of the gas in the combustion chamber 30 can extend the residence time of the VOCs exhaust gas reaching the decomposition temperature in the combustion chamber 30, so that more VOCs exhaust gas can be decomposed. Therefore, by the structure, the decomposition rate of the VOCs waste gas can be improved, the treatment effect of the VOCs waste gas is optimized, and the overall energy consumption can be reduced.

As an improvement, an airflow boosting device is further disposed in the combustion chamber 30, and the airflow boosting device can push more gas in the second chamber 33 to pass through the backflow through hole 311 and enter the first chamber 32, so as to further increase the temperature of the post-treatment VOCs waste gas, and simultaneously optimize the treatment effect of the VOCs waste gas.

Specifically, the airflow boosting device includes a fan blade 51, a transmission shaft 52 and a first driving structure 53. The fan blade 51 is disposed in the second chamber 33, the fan blade 51 is located below the backflow through hole 311, one end of the transmission shaft 52 is connected to the fan blade 51, the other end of the transmission shaft 52 extends out of the combustion chamber 30, and the other end of the transmission shaft 52 is connected to the first driving structure 53. The first driving structure 53 may be an electric motor or a pneumatic motor, etc. to drive the fan 51 and the transmission shaft 52 to rotate. When the fan blade 51 rotates, the air in the second chamber 33 can be blown into the backflow through hole 311, so that more air in the second chamber 33 passes through the backflow through hole 311 to reach the first chamber 32.

Since the temperature of the air inside the combustion chamber 30 is high, the first driving structure 53 is externally disposed, and the first driving structure 53 is prevented from being damaged at a high temperature.

In order to improve the stability of the drive shaft 52 during rotation, a limit bearing 54 is provided in the combustion chamber 30, and the drive shaft 52 is inserted into the limit bearing 54. The limit bearing 54 may be a bearing structure capable of withstanding high temperatures, such as a graphite bearing. To facilitate positioning of the limit bearing 54, a bearing support may be mounted within the combustion chamber 30, on which the limit bearing 54 is disposed. Of course, the limit bearing 54 may be disposed directly on the inner wall of the combustion chamber 30.

A stopper 55 is provided at the bottom of the partition wall 31, and the stopper 55 is positioned at the right side of the lower opening of the reflow through hole 311. The flow of gas may be blocked by the stopper 55 to reduce the flow rate of the gas at the left side of the stopper 55, and the flow rate of the gas below the backflow through hole 311 may also be reduced, so that the pressure difference between the upper end opening of the backflow through hole 311 and the lower end opening of the backflow through hole 311 is increased, so that more gas can be sucked into the backflow through hole 311. In addition, the stopper 55 blocks the gas flow, so that the fan blade 51 can blow more gas into the backflow through hole 311 during operation.

In addition, the airflow boosting device further includes a flow baffle 56 and a second driving structure 57, the second driving structure 57 is connected to the flow baffle 56, the second driving structure 57 can drive the flow baffle 56 to move up and down, and the flow baffle 56 is located above the return through hole 311. The second driving structure 57 is disposed outside the combustion chamber 30 to prevent the second driving structure 57 from being damaged due to high temperature. The second driving structure 57 can be an electric push rod or a piston cylinder.

When the second driving structure 57 drives the flow baffle 56 to move downward so that the flow baffle 56 is close to the return through hole 311, the distance between the flow baffle 56 and the upper opening of the return through hole 311 decreases, so that the gas flow rate between the flow baffle 56 and the upper opening of the return through hole 311 increases, and the pressure difference between the upper opening of the return through hole 311 and the lower opening of the return through hole 311 increases, so that more gas in the second chamber 33 is sucked into the return through hole 311.

Specifically, referring to fig. 1, as an installation manner of the baffle plate 56, the baffle plate 56 is inserted into the combustion chamber 30, an upper end of the baffle plate 56 extends out of the combustion chamber 30, and a lower end of the baffle plate 56 is located in the first chamber 32. With this arrangement, gas entering the first chamber 32 passes beneath the baffle plate 56.

Referring to fig. 2, as another installation manner of the baffle plate 56, the baffle plate 56 is completely located in the first chamber 32, and the baffle plate 56 is connected to the second driving structure 57 through a pull rod 58. With this configuration, a portion of the gas entering the first chamber 32 passes above the baffle plate 56 and a portion passes below the baffle plate 56.

The bottom surface of the baffle plate 56 is arc-shaped to guide the flow of gas and reduce the resistance to gas flow.

In practical applications, for the airflow boosting device, the fan blade 51 and the baffle plate 56 may be disposed in the combustion chamber 30 at the same time, or only one of the fan blade 51 and the baffle plate 56 may be disposed in the combustion chamber 30.

To the condition that VOCs waste gas source has ventilation unit, can directly with inlet line 41 intercommunication VOCs waste gas source can, if VOCs waste gas source does not set up ventilation unit or whole exhaust treatment system need strengthen the ventilation effect, can be provided with ventilation unit on inlet line 41 and exhaust duct 42 at least one between the two. The ventilation device may be a ventilator, blower or other device capable of achieving gas circulation.

In the above-described embodiment, the flow area of the return through holes 311 is gradually decreased from bottom to top, and the air flow velocity is gradually increased in the process of the air flowing upward along the return through holes 311, so that the pressure difference between the upper end openings of the return through holes 311 and the lower end openings of the return through holes 311 is further increased, so that more air is sucked into the return through holes 311. In addition, the lower end opening of the backflow through hole 311 is large, so that the fan blade 51 can blow gas into the backflow through hole 311 when rotating.

In the above embodiment, the heat exchanger 10 may be a plate heat exchanger or a tube heat exchanger.

In the above embodiment, it is preferable that the heat storage structure 21 is provided as a ceramic heat storage layer which is high in temperature resistance and good in oxidation resistance and corrosion resistance. In addition, the heat storage structure 21 may also be another structure, such as a metal heat accumulator or a liquid heat accumulator.

Referring to fig. 1 and 2, the exhaust gas treatment system further includes a diversion pipeline 43 and a diversion blower 44 disposed on the diversion pipeline 43, an inlet end of the diversion pipeline 43 is communicated with the air inlet pipeline 41, and an outlet end of the diversion pipeline 43 is communicated with the first chamber 32. Heat is generated when the VOCs waste gas is decomposed in the combustion chamber 30, and the decomposition of the VOCs waste gas is affected by an excessively high temperature in the combustion chamber 30. If the concentration of the exhaust gas entering from intake pipe 41 is too high, a large amount of heat is generated at the time of decomposition in combustion chamber 30, resulting in an excessive temperature in combustion chamber 30 even if burner 34 is turned off; if all of the high concentration exhaust gas enters the combustion chamber 30 after being preheated by the heat exchanger 10, the over-temperature condition in the combustion chamber 30 is aggravated. With the above structure, when the concentration of the exhaust gas in the intake duct 41 is too high, the split flow fan 44 may be turned on, so that a portion of the exhaust gas may directly enter the combustion chamber 30 without passing through the heat exchanger 10 for preheating, and the temperature of the portion of the exhaust gas is low, so that a portion of the heat in the combustion chamber 30 may be absorbed, and the temperature in the combustion chamber 30 may be prevented from being too high.

Referring to fig. 1 and 2, the exhaust gas treatment system further includes a return line 45 and a return fan 46 disposed on the return line 45, wherein an inlet end of the return line 45 is communicated with the exhaust line 42, an outlet end of the return line 45 is communicated with the intake line 41, and when the return fan 46 is operated, gas can be delivered from the exhaust line 42 to the intake line 41. When the exhaust gas treatment system is started, the temperatures of the heat exchanger 10 and the combustion chamber 30 are low, the burner 34 needs to be started to assist in increasing the temperature, so that the system can be preheated, and the backflow fan 46 is started, so that part of high-temperature gas can flow back to the heat exchanger 10, so that the temperatures of the heat exchanger 10, the combustion chamber 30 and the like can be increased, the starting temperature rising speed of the system is accelerated, and the system preheating time is shortened. In addition, at the in-process of handling VOCs waste gas, also open backflow fan 46 for the high temperature gas of part can flow through backflow pipeline 45 and carry out the hybrid heating with untreated VOCs waste gas, improves the temperature of VOCs waste gas, optimizes the heating effect of VOCs waste gas.

In some embodiments, the outlet end of the return conduit 45 may communicate directly with the inlet end of the first passage 11.

As above, the direction indicated by the arrow in the drawing is the flow direction of the gas. The flow area, i.e. the area of the cross-section of the channel in a direction perpendicular to the flow direction of the gas when flowing in the channel.

The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present invention.

Claims

1. An exhaust gas treatment system, comprising

2. The exhaust treatment system of claim 1, wherein an airflow boost device is disposed within the combustion chamber.

3. The exhaust gas treatment system according to claim 2, wherein a flow area of the return through-hole gradually decreases from bottom to top.

4. The exhaust gas treatment system of claim 2, wherein the airflow boosting device comprises a fan blade, a transmission shaft and a first driving structure, the fan blade is disposed in the second chamber and located below the backflow through hole, one end of the transmission shaft is connected to the fan blade, the other end of the transmission shaft extends out of the combustion chamber, and the other end of the transmission shaft is connected to the first driving structure.

5. The exhaust treatment system of claim 4, wherein a limit bearing is disposed within the combustion chamber, the drive shaft being disposed through the limit bearing.

6. The exhaust gas treatment system according to any one of claims 1 to 5, wherein a stopper is provided at a bottom of the partition wall, the stopper being located at a right side of a lower end opening of the return through hole.

7. The exhaust treatment system of any of claims 2 to 5, wherein the airflow boost device comprises a baffle plate and a second driving structure connected to the baffle plate, wherein a bottom of the baffle plate is disposed in the first chamber and the baffle plate is located above the return through hole, and the second driving structure drives the baffle plate to move up and down.

8. The exhaust treatment system of claim 7, wherein the bottom surface of the baffle plate is arcuate.

9. The exhaust gas treatment system of claim 1, further comprising an inlet duct, an exhaust duct, a return duct, and a return fan disposed on the return duct, wherein the inlet duct is in communication with the inlet end of the first passage, the exhaust duct is in communication with the outlet end of the second passage, the inlet end of the return duct is in communication with the exhaust duct, and the outlet end of the return duct is in communication with the inlet duct or the inlet end of the first passage.

10. The exhaust gas treatment system of claim 1, further comprising an inlet duct, a diversion duct, and a diversion blower disposed on the diversion duct, wherein the inlet duct is in communication with an inlet end of the first passage, an inlet end of the diversion duct is in communication with the inlet duct, and an outlet end of the diversion duct is in communication with the first chamber.