KR100561253B1 - A system for catalytic oxidation of vocs - Google Patents

Abstract

The present invention provides a plurality of adsorption modules arranged in parallel by an intake line and an exhaust line; Desorption intake line and desorption exhaust line extending from each of the upper and lower ends of the plurality of adsorption modules; Second heat exchange means connected to the desorption exhaust line and communicated with the desorption exhaust line from the catalytic oxidation module; A catalytic oxidation module connected to the second heat exchange means; First heat exchange means connected to the second heat exchange means and communicated by the removable intake line; And a flow path switching valve capable of blocking or blocking gas flow to the intake line, the exhaust line, the desorption intake line, and the desorption exhaust line, wherein the volatile organic compound catalytic oxidation decomposition treatment system is configured. It is to provide an efficient VOC processing system based on the system.

SCTO, Catalytic Oxidation, VOC

Description

Volatile Organic Compound Catalytic Oxidation Treatment System {A system for catalytic oxidation of VOCs}             

1 is a configuration diagram of a system piping connection state according to the present invention.

* Description of the symbols for the main parts of the drawings *

1, 2, 3: adsorption module or desorption module, 10: catalytic oxidation module,

20: first heat exchanger, 21: second heat exchanger,

40: intake line, 60: removable intake line,

50: exhaust line, 70: removable exhaust line,

40a ~ c, 50a ~ c: adsorption mode flow path change valve,

60a ~ c, 70a ~ c: removable mode flow path change valve,

80, 81, 82: concentration measuring device, 90: external discharge port,

62: desorption external gas inlet, 61: auxiliary desorption external gas inlet.

30: first blowing means, 31: second blowing means

The present invention relates to a system for removing volatile organic compounds including organic solvents discharged from industrial processes, and more particularly, to volatile organic compounds generated at places such as coating, coating, printing, and paint manufacturing processes. The present invention relates to a catalytic oxidative decomposition treatment system for volatile organic compound combustion treatment by catalytic oxidation method.

In general, a plant using an organic solvent or a production facility that purifies and stores volatile petroleum compounds, such as paint manufacturing, printing, automobile coating, general coating, and metal and plastic coating plant, inevitably includes volatile organic compounds including organic solvents. pollutants such as organic compounds (VOCs) are generated. Although most of the volatile organic compounds are present in low concentrations, they cause considerable damage to the human body, such as causing cancer, and react with nitrogen oxides under sunlight to generate optical smog, destroying global warming and the ozone layer as an international environmental problem. It is recognized. In addition, since most of the volatile organic compounds have a low boiling point, when exposed to the atmosphere, they are volatilized to cause odors, and may also cause fires in an enclosed space.

When volatile organic compounds are discharged from the process, high concentrations can be incinerated and used as heat sources, but in most processes, VOCs are emitted at low concentrations. The technology for processing volatile organic compounds is divided into direct combustion method (Thermal oxidizer) and catalytic combustion method (Catalytic Thermal Oxidizer) according to the oxidation method, which is divided into regenerative type and heat exchanger type according to the heat recovery method. The effective treatment method is determined by the concentration of volatile organic compounds. When the concentration of volatile organic compounds is higher than 6000ppm, direct combustion method that completely decomposes VOC by contacting more than 0.5 seconds at 720C or more is effective.However, when the concentration of volatile organic compounds is lower than 6000ppm, auxiliary fuel for combustion is used. Because of the need to supply, direct combustion treatment causes a problem of low economic efficiency. Volatile organic compounds that are difficult to incinerate heat due to low concentrations are treated with catalytic combustion, but even in this case, when the concentration of volatile organic compounds is too low below 2000 ppm, a large amount of energy is required to maintain catalytic combustion. Occurs. Catalytic combustion is a combustion reaction that occurs at a lower temperature than direct combustion because combustion occurs on the surface of the catalyst. In other words, if catalytic combustion is used, combustion (flameless combustion) is possible without flame.

Therefore, conventionally, in order to treat volatile organic compounds discharged at low concentrations, low concentrations of VOC are passed through an activated carbon adsorption tower, and the processing gas is released to the atmosphere, and only the high concentration of VOC gas adsorbed and concentrated on the adsorption tower is directly burned or catalytically burned. A method of reducing was devised. According to Korean Patent Registration No. 410893 (Continuous Adsorption and Regeneration Equipment), the adsorption and regeneration apparatus is proposed to arrange adsorption towers in parallel and to repeat the adsorption and regeneration cycles alternately so as not to affect the whole production process. The patent discloses that a heat exchanger for exchanging heat with the atmosphere introduced through the suction fan is connected to the downstream end of the catalytic combustion device, and the heat exchanger is connected between the high temperature gas discharged from the catalytic combustion device and the atmosphere introduced through the suction fan. It can be seen that it plays a role of lowering the temperature of the process gas discharged to the outside while simultaneously desorbing the VOC adsorbed through heat exchange. However, the patented technology is not easy to control the temperature of the atmosphere for desorption, and when activated carbon is used as the adsorbent, there is a fatal problem such as a fire hazard due to the high temperature desorption atmosphere, and the catalyst of the desorbed VOC gas is low. Before entering the combustion apparatus, there is a disadvantage that a separate flame process is required in order to secure the temperature required for catalytic oxidation, which causes an increase in operating costs including fuel and electricity costs. Above all, it is pointed out that it is not possible to adequately cope with the strengthening of environmental regulations that are strengthened because there is no separate control device for the setting of the regeneration time of the adsorption module and the catalytic oxidation device.

It is an object of the present invention to provide an efficient VOC treatment system based on a desorption mode closed loop system in a system for catalytic oxidation decomposition of volatile organic compounds.

Another object of the present invention is to provide an efficient VOC treatment system that directly uses the thermal energy of a high-temperature purge gas in a desorption mode by secondary heat exchange. Therefore, the high-temperature purge gas thermal energy is continuously heat exchanged with the desorption VOC gas and the desorption external gas, the present invention is a separate flame for the desorption VOC gas temperature rise to easily reach the temperature required in the catalytic oxidation module It is to provide a system capable of achieving the optimum temperature in the desorption mode of the system and the device for the desorption external gas.                         

In another aspect, the present invention is to provide a system capable of automatically switching to the adsorption module and the desorption mode when the concentration of the VOC is attached to one end of the adsorption module is automatically discharged to the atmosphere at a certain concentration.

The final object of the present invention is to provide a VOC treatment system having an adsorption module filled with an adsorbent which is excellent in adsorption efficiency and has no fear of fire even at high temperature exposure.

The volatile organic compound catalytic oxidation decomposition treatment system for achieving the above object is a desorbed VOC gas and desorbed hot purified gas on the basis of a desorption closed circuit system without releasing heat energy of the hot purified gas flowing out from the catalytic oxidation module to the outside. The system according to the present invention comprises: a plurality of adsorption modules arranged in parallel by an intake line and an exhaust line; Desorption intake line and desorption exhaust line extending from each of the upper and lower ends of the plurality of adsorption modules; Second heat exchange means connected to the desorption exhaust line and communicated with the desorption exhaust line from the catalytic oxidation module; A catalytic oxidation module connected to the second heat exchange means; First heat exchange means connected to the second heat exchange means and communicated by the removable intake line; And a flow path switching valve capable of blocking or blocking gas flow to the intake line, the exhaust line, the intake line for detachment, and the detachable exhaust line.

In this system, a first blowing means for forcibly blowing contaminants including VOCs is connected to the intake line end, and a second blowing means for forcing gas flow in the desorption mode closed circuit may be in communication with the desorption exhaust line. And, the lower end of the adsorption module further comprises a discharge gas concentration measuring means, the control unit for adjusting the flow path switching valve according to the measured value of the concentration measuring means may be further provided.

The present system uses the first and second heat exchange means as the thermal energy generated by the catalytic oxidation reaction in which the desorption VOC gas derived from the desorption mode is required for the catalytic oxidation module, and the desorption external gas is required for the desorption module. By distributing through, an efficient catalytic oxidation reaction and a desorption process are provided.

Hereinafter, with reference to the accompanying drawings will be described in more detail the present system.

1 is a configuration diagram of the present system piping connection state. A plurality of adsorption modules (1, 2, 3) connected in the upper and lower ends by the intake line 40 and the exhaust line 50 are arranged in parallel, and a plurality of adsorption mode flow paths for opening and closing the flow path at the appropriate points of the intake line and the exhaust line Valves 40a, 40b, 40c, 50a, 50b, 50c are interposed. The flow path switching valve is operated by a signal from a control unit not shown. A first blower 30 is mounted at the tip of the intake line, and contaminant gas including VOC from the source is forcedly blown to the intake line. On the other hand, a concentration measuring means is disposed at the end of the exhaust line, and the gas concentration emitted from each intake module is sent to the controller. At the time when a predetermined value is reached, the controller operates the flow path switching valve to end the adsorption mode and removes the desorption mode. Is switched to. At the rear of the exhaust line, an external discharge port 90 for discharging non-polluting gas to the outside is located.

Since the intake modules 1, 2, 3 have a constant adsorption amount limit, when the adsorbent in the intake module reaches the adsorption limit value, the adsorption mode in the intake module is terminated, and the desorption mode is started in the intake module. In the desorption mode, the adsorption module is defined as a desorption module. Desorption modules (1, 2, 3) connected to the upper and lower ends by the desorption intake line 60 and the desorption exhaust line 70 are arranged in parallel, for opening and closing the flow path at the appropriate points of the desorption intake line and desorption exhaust line. Desorption intake flow path switching valves 60a, 60b, 60c and dropping exhaust flow path switching valves 70a, 70b, 70c are interposed. The flow path switching valve is operated by a controller, but the controller is not shown. The detachable exhaust line 70 is connected to the catalytic oxidation module 10 via the second heat exchanger 21 and the second blower 31. The high temperature purge gas purified by the catalytic oxidation module 10 emits considerable heat energy through the second heat exchanger 21 and the first heat exchanger 20 and is discharged through the external discharge port 90. An external gas flows in through the removable intake line 60, and the removable intake line communicates with the first heat exchanger 20. In order to control the exothermic temperature of the catalytic catalytic module, it should be discharged at a constant concentration during VOC desorption, which is determined by the temperature of the desorption intake gas flowing into the desorption module. It may be introduced through the auxiliary desorption external gas inlet 61 interposed in the intake line.

In the adsorption module (1, 2, 3), the contaminants including VOCs are chemically or physically combined to temporarily store adsorption means, for example, activated carbon or zeolite alone or mixed packing. The catalytic oxidation module 10 is provided with a catalyst layer for oxidizing the VOC, and preferably, a monolith support coated with a carrier on which precious metals such as Pt and Rh are supported, but is not limited thereto.

The following describes the operation of the system.

Contaminants including volatile organic compounds are forced into the intake line 40 by the first blower 30, and at this time, the flow path switching valves 40a and 50a are branched to the intake line 40 and the respective adsorption modules. Only open the flow path of the inlet gas flow in one direction to the adsorption module (1). The volatile organic compound introduced into the adsorption module 1 is physically or chemically adsorbed with the zeolite, which is a built-in adsorbent, and other harmless clean gas flows out through the exhaust line 50 and the external discharge port 90. The concentration measuring means 80 mounted on the lower side of the adsorption module 1 continuously measures the volatile organic compound concentration of the external emission gas flowing out from the adsorption module 1 and sends a concentration signal to the controller. When the volatile organic compound concentration measured by the concentration measuring means reaches a predetermined set concentration (hereinafter referred to as a predetermined limit point), that is, the packing zeolite in the adsorption module 1 is saturated by the volatile organic compound, so that no further adsorption is possible. When the release of the volatile organic compound is started, the concentration signal from the concentration measuring means 80 is transmitted to the control unit for controlling the flow path switching valves in the system, and the control unit flows in or out of the suction module 1. Blocking the 40a and 50a prevents the inflow of further volatile organic compounds into the adsorption module 1 and controls the flow of gas in the adsorption mode in the system through the control of the flow path switching valves 40b and 50b. 2) to control the inflow to prevent the external release of volatile organic compounds from the adsorption module (1). While the adsorption mode is performed through the adsorption module 2, the desorption mode flow path switching valves 60a and 70a of the desorption intake lines are controlled and the second blower 31 is operated to control the desorption mode from the desorption module 1. It starts. Therefore, at a predetermined limit of the adsorbent, the flow path in the system requiring the desorption mode is temporarily removed from the suction intake line 60, the desorption module 1, the desorption exhaust line 70, the catalytic oxidation module 10, and the first and the first. The closed circuit leading to the two heat exchangers 20 and 21 is formed, while the other adsorption module 2 is configured with an open circuit to start the adsorption process. That is, the adsorption mode until the desorption mode is started in the adsorption module 1 is applied to the adsorption module 2 in the same manner. The contaminants from the first blower 30 enter the adsorption module 2, are adsorbed, and the adsorption process proceeds until the predetermined limit point is reached according to the concentration measurement. Therefore, this system is a volatile organic compound combustion system capable of continuously adsorption and desorption processes.

Hereinafter, the desorption mode of the adsorption module 1 saturated with volatile organic compounds will be described. At this time, the adsorption module 1 is switched to the desorption module. The volatile organic compounds bound to the packed adsorbent in the desorption module (1) pass through the catalytic oxidation module (10), and the hot gas generated by the organic material oxidation exchanges heat with the desorption external gas, and the desorption external gas is brought to an appropriate temperature. It is released by lowering the temperature of the purge gas discharged at the same time as it is warmed. In addition, the volatile organic compound desorbed by the external gas is introduced into the catalytic oxidation module 10 through the exhaust line 70, the volatile organic compound is a high-temperature purge gas and the second outflow from the catalytic oxidation module 10 After the heat exchange in the heat exchanger 21, the temperature is raised to an appropriate temperature and introduced into the catalytic oxidation module 10, the VOC is subjected to the catalytic oxidation reaction on the stacked catalyst surface. The catalytic oxidation reaction proceeds at about 200-400 ° C. to decompose into harmless carbon dioxide and water. For the catalytic oxidation reaction by the heat exchanger through the second heat exchanger, not only the flame generator, which is required in the related art, is required, but also the disadvantages in terms of maintaining the equipment, which is simple and provide auxiliary fuel, can be improved. Desorption process of the volatile organic compound in the desorption module 1 is controlled by the temperature of the desorption external gas and the flow rate by the second blowing means 31, the temperature of the desorption external gas is the desorption external gas inlet (61, 62) External gas from the external gas inlet 61 which does not undergo heat exchange with the external gas from the external gas inlet 62 which undergoes heat exchange with the hot gas generated in the catalytic oxidation module 10 among the external gas from Controlled by mixing. The desorption mode continuously proceeds in a closed circuit in the system, while in the adsorption module 2, a continuous adsorption process proceeds. The degree of adsorption in the adsorption module 2 is monitored by the concentration measuring means 81 provided at the lower end of the adsorption module 2, and when the predetermined limit point representing the saturation of the adsorbent is reached, the adsorption step is completed, and the desorption step proceeds. do. That is, as a whole, the adsorption process and the desorption process alternately and continuously proceed. At the time of the first adsorption-desorption before the normal operation of this system, a sufficient heat source for heat exchange could not be found, so an auxiliary flame facility 11 is required, but at the time of normal operation, that is, the catalytic oxidation module 10 Since the heat source is supplied through heat exchange of the heat exchangers 20 and 21 from the time of normal operation, the system can be operated without the operation of the flame facility 11.

Although the present invention has been described based on the above preferred embodiments, these examples are intended to illustrate, not limit, the invention. It will be apparent to those skilled in the art that various changes, modifications, or adjustments to the above embodiments can be made without departing from the spirit of the invention. Therefore, the protection scope of the present invention should be construed that the appended claims cover all changes, modifications or various adjustments of the above embodiments.

According to the present invention described above, by applying the oxidized decomposition high-temperature reaction heat directly to the desorption mode, equipment such as a flame facility for maintaining the high temperature required for complete combustion in the catalytic oxidation reaction is not required, thereby reducing preheating cost and adsorption efficiency. With this excellent, adsorbent module filled with an adsorbent that does not cause fire problems even at high temperature exposure, it is possible to eliminate the instability of the conventional system that could not completely remove the adsorbent due to fire risk, and to attach the concentration measuring device. Therefore, it is possible to provide a fully automatic system of adsorption, desorption, and catalytic oxidation so that the adsorption module can be replaced and desorption-catalyzed automatically when the volatile organic compound above a certain concentration is discharged to the atmosphere.

Claims (4)

A plurality of adsorption modules arranged in parallel by an intake line and an exhaust line; Desorption intake line and desorption exhaust line extending from each of the upper and lower ends of the plurality of adsorption modules; Second heat exchange means connected to the desorption exhaust line and communicated with the desorption exhaust line from the catalytic oxidation module; A catalytic oxidation module connected to the second heat exchange means; First heat exchange means connected to the second heat exchange means and communicated by the removable intake line; And a flow path switching valve capable of blocking or blocking gas flow to the intake line, the exhaust line, the desorption intake line, and the desorption exhaust line. 2. The catalytic oxidation of volatile organic compounds according to claim 1, wherein the first blowing means for forcibly blowing the contaminants including VOCs is connected to the front end of the intake line, and the second blowing means is interposed in the desorption exhaust line. Decomposition Treatment System. According to claim 1, The lower end of the adsorption module, characterized in that it further comprises a discharge gas concentration measuring means, volatile organic compound catalytic oxidation decomposition processing system. The catalytic oxidative decomposition treatment system according to claim 1, wherein an auxiliary desorption external gas inlet is further opened to the desorption intake line.

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