JP2003074826A - Thermal storage combustion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect a rotary distribution valve from seizure during an emergency stop, in a rotating distribution type regenerative combustion device to purify volatile organic compound (VOC)-containing gas. SOLUTION: The thermal combustion device is provided with the rotary distributing valve 7 to distribute gas by switching a kind of gas at a distribution port 4a, each heat storage chamber 14 coupled to the distribution port 4a through a coupling duct 13, and a combustion furnace 15 connected to each thermal storage chamber 14. VOC- containing gas 10 being one of gases id fed in the forward directions of the coupling duct, a thermal storage chamber, and the combustion furnace from the rotary distribution valve and treated gas 8 at the combustion furnace is fed as different gas in a reverse forward direction. In a so formed heat storage combustion device, an atmospheric air induction port 11 is formed in the thermal heat storage chamber 14 and a radiating port 12 is formed in the combustion furnace 15. The atmospheric air induction port 11 and the radiation port 12 are opened and the atmosphere enters during an emergency stop that heaters for VOC-containing gas, a rotary distribution valve, and the combustion furnace are stopped, the thermal storage chamber and the combustion furnace are cooled, and the rise in the temperature of the coupling duct 13 and the rotary distribution valve 7 due to thermal conduction is blocked to protect the devices from seizure.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a volatile organic compound.
VO including (Volatile Organic Compound: VOC for short)
The present invention relates to a heat storage and combustion device that burns a C-containing gas for purification treatment and reuses heat storage obtained from the treated gas for preheating of a VOC-containing gas, and particularly protects the device from heat during an emergency stop of the device. The present invention relates to a heat storage and combustion device suitable for.

[0002]

2. Description of the Related Art Exhaust gas containing volatile organic compounds (VOC) such as toluene, xylene and styrene is emitted from automobile painting factories, metal washing and printing factories. It has been revealed that such a VOC-containing gas has a VOC concentration of several ppm to several% at most, but has a considerably great effect on the environment. The VOC-containing gas is, for example,
(1) Photochemical smock is generated by reacting with NOx, which causes forests to die and have an adverse effect on the human body. (2) Causes health problems such as carcinogenicity to the human body. (3) Main component of photochemical oxidant Global warming is caused by an increase in ozone, which is the troposphere. Therefore, in the above-mentioned industry, the VOC-containing exhaust gas is purified and then discharged into the atmosphere.

As a VOC treatment method, a direct combustion type,
There are a catalytic combustion type, a thermal storage combustion type, a catalytic combustion / thermal storage type, a concentration type, and a biological treatment type, but the thermal storage combustion type (including catalytic combustion) is considered to be promising in view of running cost and maintenance. In the heat storage combustion method, the flow path for supplying the VOC-containing gas before processing and the flow path for returning the processed purified gas are the same, and as a method for switching the gas flow, a multiple valve method in which a plurality of valves are combined and a rotation method are used. There is a distribution valve system, and it is generally said that the rotary distribution valve system is superior to the multiple valve system in terms of downsizing and reduction in pressure fluctuation.

[0004]

A rotary distribution valve type heat storage combustion apparatus is generally constructed by sequentially arranging a rotary distribution valve, a heat storage chamber and a combustion furnace. The heart of this heat storage combustion device is a rotary distribution valve, and in order to achieve a combustion rate of 95% or higher and temperature efficiency, the sealing property between the rotating portion of the rotary distribution valve and the fixed portion supporting the rotating portion is required. In order to secure the above, the sliding parts of both parts have a highly accurate sealing structure.
In particular, when the heat storage combustion device is stopped or in the case of an emergency stop, sufficient protection is required to prevent the sliding portion from being damaged by heat.

For example, during steady operation, the temperature distribution of the heat storage body installed in the heat storage chamber has a shape in which the temperature inside the furnace and the temperature of the gas supplied from the rotary distribution valve are connected linearly. In this state, when the electric power supply to the heater of the combustion furnace, the blower that supplies the VOC-containing gas to the rotary distribution valve, and the drive motor of the rotary distribution valve is stopped, the temperature gradient in the heat storage body is gradually alleviated and the low temperature side The temperature of the existing rotary distribution valve also rises. For this reason, there is a problem that if a duct or hose connecting the rotary distribution valve and the heat storage chamber or a seal member of the rotary distribution valve is made of an organic material, it is burnt out or, in the worst case, causes ignition. .

An object of the present invention is to provide a rotary storage valve type heat storage combustion apparatus for purifying VOC gas, which is equipped with a protection mechanism for suppressing a temperature rise of equipment such as a distribution valve in the case of an emergency stop of the apparatus. To provide a device.

[0007]

In order to achieve the above object, a heat storage combustion apparatus of the present invention includes a rotary distribution valve for distributing while distributing gas types to a plurality of distribution ports, and a plurality of rotary distribution valves. A plurality of heat storage chambers each of which is connected to a distribution port through a connecting duct and in which a heat storage body is installed, and a combustion furnace which is connected to the plurality of heat storage chambers and in which a heater is installed, and which rotates a rotary distribution valve. A sealing material is provided between a portion and a fixed portion that supports the rotating portion, and VOC-containing gas supplied from a blower with one kind of gas is fed from the rotary distribution valve in the forward direction of the connecting duct, the heat storage chamber, and the combustion furnace. However, in a heat storage combustion device configured to send out the processed gas generated by burning the volatile organic compound-containing gas in the combustion furnace with another type of gas in the reverse forward direction, opening and closing at the bottom of each heat storage chamber Atmosphere attraction with valve The and-off valve with thermal vents provided in the combustion furnace top, characterized in that to open the respective opening and closing valves when interrupted during device operation blower, rotary distributor valve and the power supply to the heater.

In the heat storage combustion apparatus, it is preferable to install a catalyst on the combustion furnace side in the heat storage chamber adjacent to the heat storage body.

In the steady operation of the heat storage and combustion apparatus of the present invention, the VOC-containing gas supplied from the blower stores heat through the connecting duct which is successively connected to the VOC-containing gas port of the rotary distribution valve as the rotary distribution valve rotates. It is sent to the chamber and heated there by the heat storage of the heat storage body, and is heated by the heater in the combustion furnace and burned to be purified into a treated gas. The treated gas is transferred from the combustion furnace to the treated gas port of the rotary valve through the heat storage chamber and the connecting duct, which are sequentially connected to the processed gas port of the rotary valve, and then through the treated gas port of the rotary distribution valve to the rotary distribution valve. It leaks to the outside. Purge air flows through the purge air port of the rotary distribution valve when the device is stopped or started.

The atmosphere inlet port with the on-off valve and the heat radiation port with the on-off valve function as a protection mechanism when the heat storage combustion device is stopped in an emergency. That is, when power supply to the blower, rotary distribution valve and heater is stopped due to an emergency stop, or when an unexpected power failure occurs, each open / close valve is "opened" so that the atmosphere is a natural convection and the atmosphere attracts the atmosphere. Flows into the heat storage chamber from the heat dissipation chamber, flows out from the heat dissipation port through the combustion furnace, and the high temperature gas in the heat storage chamber and the combustion furnace is expelled by the flow of the atmosphere to cool the heat storage chamber and the combustion furnace. This cooling prevents heat from being transferred from the heat storage chamber to the connection duct or the rotary distribution valve, and thus protects the sealing material of the connection duct and the rotary distribution valve from damage due to heat. Therefore, it becomes possible to adopt a connecting duct and a sealing material using an organic material having a low heat resistant temperature.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A heat storage and combustion device according to an embodiment of the present invention will be described below. This heat storage combustion device
Schematically, as shown in FIG. 1, three kinds of gases, namely, volatile organic compounds (VO) are abbreviated.
A gas 10 containing C) (referred to as VOC-containing gas), a processed gas 8 and a purge air, which will be described later, are distributed while switching to a plurality of distribution ports 4a, and a flexible duct as a connecting duct from the distribution valve 7. Thirteen
A plurality of heat storage chambers 14 for preheating the VOC-containing gas 10 supplied through the combustion chamber 15, a heating furnace 15 for heating the VOC-containing gas 10 fed from the heat storage chamber 14 by the heater 1 to purify the VOC-containing gas 10, and a bottom portion of each heat storage chamber 14. Atmosphere inlet 11 with an on-off valve that takes in outside air from the top, and combustion furnace 15 from the top to combustion furnace 15
And a heat radiation port 12 with an on-off valve for discharging the gas inside, and further, the treated gas 8 purified in the combustion furnace 15 from the heat storage chamber 14 to the flexible hose 13 and the distribution valve 7 to the VOC-containing gas 10 In contrast to the above, it is configured so as to pass through in the reverse forward direction and be discharged, and the purge air 9 flows in the forward direction like the VOC-containing gas 10. The heat storage and combustion device of the present invention is provided with the above-mentioned atmosphere induction port 11 and heat dissipation port 12
Is characterized in that is provided as a protection mechanism.

The components will be described in more detail. The distribution valve 7 is a quadruple pipe, and has a gas header 6 having three annular flow passages formed between adjacent pipes, and a port (total 3 in total) for each annular flow passage of the gas header 6. A fixed valve having a disk-shaped rotary valve 5 having a port) and eight distribution ports 8a sequentially connected to the annular flow paths of the gas header 6 via the ports of the rotary valve 5 as the rotary valve 5 rotates. 4 and so as to be stacked in order. A rotary shaft (not shown) connected to the rotary valve 5 is arranged in the central space of the quadruple pipe of the distribution valve 7, and the rotary shaft is driven by a motor (not shown). Further, packing (not shown) is provided between the rotary valve 5 and the fixed valve 4 as a sealing material for preventing gas leakage.

Of the three annular flow paths of the gas header 6,
The outer channel 6a contains the treated gas 8, the central channel 6c contains the VOC-containing gas 10, and the inner channel 6b contains the purge air 9.
It is a flow path for flowing.

The three ports of the rotary valve 5 are a port 5a for the treated gas 8, a port 5c for the VOC-containing gas 10 and a port 5b for the purge air 9. Here, the port 5a for the treated gas 8 and the port 5c for the VOC-containing gas 10 are used.
Are each formed to have a length corresponding to 1/4 rotation of the rotary valve 5, the purge air 9 port 5b is formed to have a length corresponding to 1/8 rotation, and each port is equivalent to 1/8 rotation. Just away. As the rotary valve 5 rotates, the fixed valve 4
The VOC-containing gas 10 passes upward and the treated gas 8 passes downward through the individual distribution ports 4a, and this procedure is repeated. However, the purge air 9 is supplied according to the condition of the apparatus such as when the combustion is stopped.

The heat storage chamber 14 consists of eight chambers arranged in parallel, and the lower part of each chamber is connected to the distribution port 8a of the fixed valve 4 by a flexible duct 13. Here, the flexible duct 13 has a heat resistant temperature of 80 ° C. φ80 mm × 300 mm
I use the long one. 8 flexible ducts 13
Is a so-called manifold portion for distributing or collecting gas. One heat storage chamber 14 has a cross section of 150 mm square, 600
With a height of mm, a noble metal is supported on the heat storage body 3 composed of a cordierite (kinseite: magnesium aluminosilicate) honeycomb (cell density 210 cell / in ² ) and the base material of the heat storage body 3 at a height of mm. It has a built-in catalyst 2. In addition, the combustion furnace installed above the eight heat storage chambers 14 is 3
The height was set to 00 mm.

The steady-state operation of the heat storage combustion apparatus configured as described above will be described. The VOC-containing gas 10 is supplied to the distribution valve 7 by a blower (not shown). The VOC-containing gas 10 that has flowed into the annular flow path 6c formed in the gas header 6 of the distribution valve 7 is opened by the port 5c as the rotary valve 5 rotates, and flows from the distribution port 4a of the fixed valve 4 through the flexible duct 13 into the heat storage chamber. 14 and is gradually heated by the stored heat of the heat storage body 3 while passing therethrough,
The VOC decomposition reaction is promoted by the catalyst 2, and then flows into the combustion furnace 15 where it is purified by heating and combustion by the heater 1 and becomes the treated gas 8. The processed gas 8 passes from the combustion furnace 15 through the heat storage chamber 14 and the flexible duct 13 in order, and as the rotary valve 5 rotates, the port 5 a.
Through the distribution valve 4 of the fixed valve 4, the port 5a, and the annular flow path 6a of the gas header 6 which are sequentially opened, and flow out of the heat storage combustion device. The treated gas radiates heat to the heat storage body 3 while passing through the heat storage chamber 14 and the temperature thereof gradually decreases, and the heat storage body 3 stores heat for the VOC-containing gas 10 that passes therethrough next. Looking at the individual distribution ports 14, during one revolution of the rotary valve 5, the inflow of the VOC-containing gas 10 and the outflow of the treated gas 8 occur sequentially in sequence. , Purge air 9
It is appropriately supplied depending on the situation of the device. In this way, the heat storage combustion apparatus continuously purifies the VOC-containing gas 10. The heater 1 is also used as a preheat heater for preheating the combustion furnace when the heat storage combustion device is started in a cold state.

Now, the atmosphere inlet 11 characterizing the present invention
The heat dissipation port 12 will be described. As shown in Figure 1,
The atmosphere intake port 11 is composed of a pipe with an electromagnetic valve 16 and is provided at the bottom of each heat storage chamber 14, and the heat dissipation port 12 is also composed of a pipe with an electromagnetic valve 16 and is provided at the top of the combustion furnace 15. The atmosphere inlet 11 provided in each heat storage chamber 14 has one atmosphere inlet side, but it does not necessarily have to be one and may be separated. The solenoid valve 16 used was closed when energized and opened when not energized.

The atmosphere introducing port 11 and the heat radiating port 12 are
Activate the thermal storage combustion device during operation in the event of an emergency stop or unscheduled power failure. That is, when power supply to the blower that feeds the VOC-containing gas 10 to the distribution valve 7, the motor that drives the distribution valve 4, and the heater 15 for the combustion 15 is cut off for an emergency stop, the atmosphere induction port 11 and the heat radiation port 12 The respective electromagnetic valves 16 are opened to allow atmospheric air to flow into each heat storage chamber 14 by natural convection and to flow out from the heat radiation port 12. At this time, the flow of the atmosphere is the processed gas or VO that fills each heat storage chamber 14.
The C-containing gas and the high temperature gas in the furnace are expelled to cool each heat storage chamber and the combustion furnace. As a result, heat conduction from each heat storage chamber 14 to the lower flexible duct 13 and the distribution valve 7 is blocked.

Next, referring to FIG. 2, the temperature change of each part of the heat storage combustion apparatus of the present invention during an emergency stop will be described in comparison with a conventional apparatus. At the time of an emergency stop, the temperature inside the combustion furnace 15 is high (for example, 8
50 ° C.), and the temperature of the lower end of the heat storage body 3 (distribution valve side) is, as shown by the solid line B, low temperature during steady operation.
Although it rises a little above (several tens of degrees higher than the atmospheric temperature), it reaches a steady state after a certain period of time. Thus, the temperature of the lower end of the heat storage body 3 is the flexible duct 1 connected below the heat storage body 3.
3 and the distribution valve 7 are kept at the heat-resistant temperature (one-dot chain line C) or lower. On the other hand, in the conventional apparatus, since the gas in the combustion furnace and the gas in each heat storage chamber are mixed by convection without the atmospheric air inlet and the heat radiating port according to the present invention, the temperature in the furnace is steep as shown by the dotted line a. The temperature at the lower end of the heat storage body is reduced to the dotted line b.
As indicated by, the temperature rises sharply and both temperatures approach each other. Therefore, heat conduction occurs from the heat storage body whose temperature has risen to the flexible duct and the distribution valve below, and the packing of the flexible duct and the distribution valve becomes higher than their heat resistant temperatures, and burning is inevitable.

The protection mechanism consisting of the air intake port 11 and the heat radiation port 12 is effective not only during an emergency stop but also during a normal operation stop. Until now, when the heat storage combustion device was normally shut down, the blower or distribution valve cannot be stopped until the heat storage combustion device is idle and the heat storage body is cooled for a certain time after the heater of the combustion furnace is stopped. . In particular, since the temperature efficiency of the heat exchanger in the heat storage chamber is higher than 95% and it is difficult to radiate heat, idle operation for a considerable time is required for cooling the heat storage chamber, which is not preferable in operation. Therefore, if the protective mechanism (functionally, a cooling mechanism) according to the present invention is used to open the atmosphere, the heat storage combustion device can be immediately stopped without providing a cooling period.

Next, the result of the confirmation experiment for confirming the effect of the protection mechanism composed of the atmosphere inlet 11 and the heat dissipation port 12 will be described. The size of each component of the heat storage combustion device is as described above, and the flexible duct 13 has a heat resistant temperature of 80 ° C. φ8.
The length is 0 mm x 300 mm, and the heat storage chamber 14 has a cross section of 150 mm.
The corners are 600 mm high and contain cordierite heat storage 3 and precious metal catalyst 2, and the combustion furnace is 300 mm high. Air containing 100 ppm of toluene as a simulated VOC gas was supplied to this heat storage and combustion apparatus at 5 m ³ / min and air as a purge gas was supplied at 0.6 m ³ / min, and steady operation was performed while maintaining the furnace temperature at 850 ° C. constant. The performance of VOC treatment equipment is a purification rate of 95% or more, a heat recovery rate of 95% or more, and a pressure loss of 2 to 2.
It was 5 kPa. In this state, power supply to the heater, blower and distribution valve 7 was cut off. At the same time, the air intake port 11 attached to the bottom of each heat storage chamber 14 and the heat radiation port 12 attached to the top of the combustion furnace 15 were opened. As a result, air is taken in from below the heat storage chamber 14, and high-temperature gas is discharged from above the combustion furnace 15. As a result, it was found that the temperature below the heat storage body 3 was maintained at approximately "atmospheric temperature + 20 ° C" or lower. Therefore, it was found that the temperature of the flexible duct 13 that connects the heat storage chamber 14 and the distribution valve 7 and the temperature of the distribution valve 7 were kept low, and there was no problem. This effect is the same with the heat storage combustion method that does not use a catalyst.
It was found that the temperature below the heat storage body was maintained at "atmospheric temperature + 40 ° C" or less even when the power supply was cut off at 0 ° C.

For comparison, a steady-state operation was carried out in the same manner as in the above-mentioned confirmation experiment, using a heat storage combustion device obtained by removing the protective mechanism for the atmosphere induction port 11 and the heat radiation port 12 from the device used in the confirmation experiment. After that, the power supply to the heater, blower and distribution valve was cut off. As a result, the bottom of the heat storage chamber 14 rises to 180 ° C., and the flexible duct 13 made of an organic material is used.
Was burned.

Then, instead of the flexible duct made of an organic material, a flexible duct made of stainless steel was connected to the distribution rotary valve 7 and each heat storage chamber 14, and a similar experiment was conducted. This time, the temperature on the distribution valve 7 side was 120 ° C. The temperature rose to near, and an odor was generated that decomposed the grease in the bearing that supports the rotation of the rotary distribution valve.

This phenomenon becomes more serious when heat storage combustion is performed without using a catalyst. The temperature under the heat storage body is 3
The temperature could rise to 00 ° C., and it was found that organic materials cannot be used for flexible ducts and sealing materials.

As described above, in this heat storage and combustion device, by providing the atmosphere induction port at the bottom of each heat storage chamber and the heat radiation port at the top of the combustion furnace as a cooling mechanism for both devices, the heat storage is performed even when the device is emergency stopped. The flexible duct that connects the chamber and the distribution valve can be protected against heat, and the sealing material of the distribution valve can be protected against heat. In particular, since natural convection of air is used for cooling the equipment, a major feature is that no auxiliary power source or external energy is required for this cooling. Further, even when the apparatus is normally stopped, the present cooling mechanism can be used to stop the apparatus without the required cooling operation, which not only improves operability but also saves energy.

[0026]

According to the present invention, a rotary distribution valve type heat storage combustion apparatus for purifying VOC gas is provided with a protection mechanism for flowing the atmosphere from the heat storage chamber through the combustion furnace to release heat to the atmosphere. Even if the device is stopped suddenly, the flexible duct and rotary distribution valve that are sequentially connected to the heat storage chamber can be maintained at a low temperature, and the flexible duct made of organic material and the seal material of the rotary distribution valve can be protected from damage due to heat. it can.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a heat storage combustion device according to an embodiment of the present invention.

FIG. 2 is a diagram comparing a temperature change of each part of the heat storage combustion apparatus of the present invention at the time of an emergency stop with a conventional technique.

[Explanation of symbols]

1 heater 2 catalyst 3 heat storage 4 fixed valve 4a Distribution port 5 rotary valve 6 gas header 7 distribution valve 8 treated gas 9 Purge air 10 VOC gas 11 Atmosphere attraction 12 Heat dissipation port 13 Flexible duct 14 heat storage room 15 Combustion furnace 16 solenoid valve

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3K062 AA24 AB01 AC19 DB23                 3K078 AA04 BA17 BA21 DA26 DA32                       EA10

Claims (2)

[Claims] 1. A rotary distribution valve that distributes gas to a plurality of distribution ports while switching the gas type, and the plurality of distribution ports of the rotary distribution valve are connected to each other via connecting ducts, and a heat storage body is installed inside. A plurality of heat storage chambers, a combustion furnace connected to the plurality of heat storage chambers and having a heater installed therein, and a seal member provided between a rotating portion of the rotary distribution valve and a fixed portion supporting the rotating portion, Then, a volatile organic compound-containing gas supplied from a blower with one type of the gas is fed from the rotary distribution valve in the forward direction of the connection duct, the heat storage chamber, and the combustion furnace, and with another type of the gas. In a heat storage combustion apparatus configured to deliver a treated gas generated by burning the volatile organic compound-containing gas in the combustion furnace in a reverse forward direction opposite to the forward direction, a bottom portion of each of the plurality of heat storage chambers On-off valve An air intake port, and a heat dissipation port with an on-off valve at the top of the combustion furnace, so that each of the on-off valves is opened when power supply to the blower, the rotary distribution valve, and the heater is cut off during operation of the apparatus. A heat storage and combustion device characterized in that 2. A catalyst is installed adjacent to the heat storage body on the combustion furnace side in the heat storage chamber.
The heat storage combustion device described.