JP2008039226A - Exhaust gas incinerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a heat recovery rate when preheating exhaust gas to be treated, and further eliminate exhaust gas leakage without introducing into an incinerator, exhaust gas preheated at a high temperature after being taken out from a preheater or a heating tube in the incinerator, in an exhaust gas flame incineration treatment. <P>SOLUTION: This exhaust gas incinerator has an introducing port introducing exhaust gas into the exhaust gas incinerator, and in the exhaust gas incinerator, the introducing port has an insertion tube part. Since exhaust gas temperature is preheated up to around exhaust gas combustion temperature, an amount of fuel to be used is remarkably reduced. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an exhaust gas incinerator for directly burning and treating exhaust gas containing malodorous components and harmful organic components.

Malodorous components and harmful organic components contained in the exhaust gas are decomposed by reacting with oxygen in the combustion air, usually at a high temperature of about 800 ° C., and turning into harmless carbon dioxide and moisture. For example, in the case of exhaust gas containing hydrocarbon-based volatile organic substances, it can be decomposed at a high temperature of about 600 to 800 ° C., and can be made odorless and harmless exhaust gas. Further, in the case of exhaust gas containing PCB and dioxins, it can be rendered harmless at a high temperature of about 1100 ° C. The method of treating exhaust gas based on this method has been practiced for a long time since its treatment effect is reliable.

  On the other hand, in this method, it is necessary to heat the exhaust gas to a high temperature. For this reason, a large amount of fuel is required when the organic substance concentration in the exhaust gas is low. Usually, the organic substance concentration is mostly low. Therefore, in order to save fuel, it is an essential requirement to recover the heat of the high-temperature exhaust gas after treatment.

  The conventional heat recovery method is a method in which the exhaust gas to be treated is supplied to a preheater before being introduced into the exhaust gas incinerator, where it is heat-exchanged with the high temperature combustion gas and preheated to a high temperature. As the structure of the preheater, there are a heat exchanger type and a system in which a heating tube is installed in a furnace. In this case, the preheated exhaust gas is taken out from the preheater and then introduced into the exhaust gas incinerator. Or it takes out from the heating pipe in an exhaust gas incinerator to the collecting pipe outside a furnace, and introduces it again in the combustion chamber of an exhaust gas incinerator. Since this method is a method of recovering heat by a heat transfer method, it is necessary to provide a temperature difference between the high-temperature combustion gas and the exhaust gas, and there is a disadvantage that the heat recovery rate is poor. Also, since the preheated exhaust gas has a high temperature, when this conduit is attached to the exhaust gas incinerator, the conduit is at a high temperature and the furnace wall of the exhaust gas incinerator is at a low temperature. It is necessary to apply. This requires structurally advanced technology and is likely to cause trouble.

  As a conventional method, a method using a heat storage type heat exchanger is also implemented. In this method, a heat accumulator for preheating the exhaust gas to be treated is installed, heated by high-temperature combustion gas, and then the flow of the exhaust gas is switched to bring the exhaust gas into contact with the high-temperature heat accumulator. The exhaust gas is then preheated to a high temperature. Although this method is very excellent as a heat recovery rate, it is necessary to switch the flow of exhaust gas, and at that time, leakage of the exhaust gas occurs. Therefore, there exists a fault that the processing performance of exhaust gas will fall.

  The present invention seeks to overcome the disadvantages of conventional methods in exhaust gas combustion treatment. That is, the object is to increase the heat recovery rate from the high-temperature combustion gas. At that time, the exhaust gas preheated to a high temperature is not taken out from the preheater or the in-furnace heating tube and then introduced again into the incinerator, and the exhaust gas leak is further eliminated.

  As a result of intensive studies, the present inventors have made the present invention. That is, an exhaust gas incinerator for directly combusting and treating exhaust gas has an introduction port for introducing exhaust gas into the exhaust gas incinerator, and the introduction port has an insertion pipe portion in the exhaust gas incinerator. It is an exhaust gas incinerator.

  When carrying out the method of the present invention, the exhaust gas temperature can be preheated to near the exhaust gas combustion temperature. Therefore, the amount of fuel used can be greatly reduced. Furthermore, since there is no structure for extracting the exhaust gas from the preheater or the furnace heating tube to the outside, there is no risk of structural trouble.

  The present invention will be described in detail. Exhaust gas containing malodorous components and harmful organic components is usually sucked and blown from a source by a fan. The exhaust gas is introduced into the furnace from an inlet installed in the exhaust gas incinerator. At this time, it is desirable to divide and introduce into pipes having a pipe diameter of about 1B to 6B. Therefore, when the exhaust gas flow rate is large, the number of introduction pipes increases.

  Next, each of these introduction pipes has an insertion pipe extending into the furnace. The insertion tube is connected to the inlet and extends long into the furnace. In the furnace, they are arranged in the vertical direction or the horizontal direction. It arrange | positions along the inner wall surface in a furnace, or arrange | positions in a tube row | line | column like a multi-tube heat exchanger. The exhaust gas is introduced into the furnace through the inlet and the insertion tube. Since the exhaust gas flows inside the insertion tube and the outside is the atmosphere in the furnace and the high-temperature combustion gas flows, the exhaust gas in the insertion tube is heated while flowing. That is, the insertion tube plays the role of a heating tube for preheating the exhaust gas before jetting it into the furnace. If the length of the insertion tube is sufficiently long, the exhaust gas temperature rises to near the high temperature combustion gas temperature. By extending the length of the insertion tube, the exhaust gas temperature can be raised from the high temperature combustion gas temperature to a temperature lower by about 50 ° C.

  When the combustion temperature of the exhaust gas is about 800 ° C. or less, 18-8 stainless steel can be used as the material of the insertion tube, but when it is about 1100 to 1200 ° C., high-grade heat resistant steel needs to be used. However, at locations where it is in direct contact with the flame of the burner, the metal tube is oxidized at a high temperature and its structural strength tends to decrease, so the life is short and not practical. Therefore, in the present invention, it is desirable to use a ceramic tube for the high temperature portion of the end portion of the insertion tube. Or it is desirable to arrange so that the flame of a burner may not hit directly.

  The terminal end of the insertion tube remains in the furnace, and the preheated exhaust gas is ejected from the insertion pipe into the exhaust gas incinerator. At this time, the insertion tube remains disposed inside the furnace and does not come out of the furnace body. Therefore, the low-temperature furnace body and the high-temperature insertion tube are not joined, and there is no part that causes structural trouble.

  The exhaust gas ejected into the exhaust gas incinerator is mixed with high-temperature combustion gas by a fuel burner and heated to the incineration temperature, and malodorous components and harmful organic components are combusted and decomposed. And it flows in the furnace as high temperature combustion gas, and flows in contact with the insertion tube. At that time, the exhaust gas flowing inside the insertion tube is heated, and the temperature of the exhaust gas decreases. By extending the length of the insertion tube, the temperature can be lowered from the inlet temperature of the exhaust gas to a temperature about 50 ° C. higher.

  The method of the present invention will be described in more detail based on examples. In FIG. 1, 1 is an exhaust gas incinerator main body. The incinerator of this embodiment is a horizontal cylindrical type, but there is no restriction on the incinerator structural type, and it can be implemented with various structures such as a vertical cylindrical type and a horizontal square type. An exhaust gas inlet 13 is attached to the exhaust gas incinerator 1, and an insertion tube 2 is connected thereto. The insertion tube 2 extends into the exhaust gas incinerator 1 and is fixed by a fixture 10. Although only one inlet 13 and insertion tube 2 are shown in FIG. 1, in a normal implementation, a large number of insertion tubes are installed. Reference numeral 4 denotes a partition wall of the combustion chamber 12 in the exhaust gas incinerator and is made of a refractory material. The outlet 11 at the end of the insertion tube 2 passes through the partition wall 4 and communicates with the combustion chamber. When penetrating the partition wall 4, the insertion tube 2 is loosely installed between the partition wall 4 so that it can slide according to thermal expansion. The exhaust gas 6 is introduced from the introduction port 13, flows through the insertion tube 2, is heated during that time, reaches the outlet 11 at the terminal end, and is ejected into the combustion chamber 12.

  A combustion device 3 is installed in the combustion chamber 12 of the exhaust gas incinerator, and fuel 8 and combustion air 9 are supplied to perform combustion. The inside of the combustion chamber 12 is heated to a temperature suitable for exhaust gas treatment, which is 1200 ° C. in this embodiment. The exhaust gas 6 has a high temperature in the combustion chamber 12, and malodorous components and harmful organic components are decomposed to become high-temperature combustion gas.

  The high-temperature combustion gas exits from the combustion chamber 12 and flows into the incinerator while being in contact with the insertion tube 2. At this time, heat is exchanged with the exhaust gas flowing through the insertion tube, and the temperature of the exhaust gas is lowered and the exhaust gas 7 is discharged from the incinerator as a processed exhaust gas 7.

  In this example, the temperature in the combustion chamber 12 was 1200 ° C., and the temperature of the treated exhaust gas 7 was 200 ° C. Therefore, the heat recovery rate was (1200−200) / 1200 = 83%.

  In FIG. 2, 21 is an exhaust gas incinerator main body. An exhaust gas inlet 33 and an insertion pipe 22 are disposed in the exhaust gas incinerator 21 and fixed by a fixture 30. In FIG. 2, only one inlet and insertion tube 22 are shown, but in a normal implementation, a large number of insertion tubes are installed. A ceramic tube 24 is attached to the end portion of the insertion tube 22. The connection between the insertion tube 22 and the ceramic tube 24 is loosely connected, and is installed so as to slide in accordance with the mutual thermal expansion difference. The exhaust gas 26 is introduced from the introduction port, passes through the insertion tube 22, further flows through the ceramic tube 24, and is ejected from the lower ejection port 31 into the combustion chamber 32.

  A combustion device 23 is installed in the combustion chamber 32 of the exhaust gas incinerator, and fuel 28 and combustion air 29 are supplied to perform combustion. The inside of the combustion chamber 32 is heated to a temperature suitable for exhaust gas treatment, that is, a high temperature of 800 ° C. in this embodiment. The exhaust gas 26 has a high temperature in the combustion chamber 32, and malodorous components and harmful organic components are decomposed to become high-temperature combustion gas.

  The high-temperature combustion gas exits from the combustion chamber 32 and flows into the incinerator while being in contact with the insertion tube 22. At this time, heat is exchanged with the exhaust gas flowing inside the insertion tube, the temperature is lowered, and the treated exhaust gas 27 is discharged from the incinerator.

  In this example, the temperature in the combustion chamber 32 was 800 ° C., and the temperature of the treated exhaust gas 7 was 100 ° C. Therefore, the heat recovery rate was (800-100) / 800 = 88%.

  It is desirable that the exhaust gas 26 shown in the second embodiment is heated to the highest possible temperature and then ejected from the ejection port 31 below the combustion chamber 32. For this purpose, the ceramic tube 24 is installed in the second embodiment, but the method shown in FIG. 3 is also possible in addition to this method.

In this method, the refractory heat insulating material at the bottom of the incinerator main body 21 is formed into a hollow shape, and the exhaust gas 26 is introduced therein. In FIG. 3, reference numeral 41 denotes a hollow portion formed by processing the refractory heat insulating material 25 of the incinerator main body into a hollow shape. The upper part of the ventilation cavity 41 is connected to the insertion tube 22, and thus the exhaust gas 26 is introduced. The ventilation cavity 41 and the insertion tube 22 are loosely installed so as to slide in accordance with the mutual thermal expansion difference. The inside of the ventilation cavity 41 is a space, and the exhaust gas 26 flows downward. The exhaust gas 26 passes through the ventilation cavity 41 and is ejected from the lower ejection port 31 to the lower portion of the combustion chamber.

  In FIG. 3, only one exhaust gas insertion pipe 26 is shown. In that case, it is appropriate to install a large number of ventilation cavities 41 in the same manner, and to install over the entire circumference of the inner wall of the incinerator. That is, it is a method in which an inner wall is further installed inside the refractory heat insulating material 25 of the incinerator to form a donut shape, and the exhaust gas flows between them.

Illustration of horizontal body of exhaust gas incinerator Illustration of exhaust gas incinerator vertical cylindrical body Processed fire-resistant heat insulating material of exhaust gas incinerator

Explanation of symbols

1: Exhaust gas incinerator main body 2: Insertion pipe 3: Combustion device 4: Partition wall 5: Refractory heat insulating material 6: Exhaust gas 7: Treated exhaust gas 8: Fuel 9: Combustion air 10: Fixing tool 11: Jet port 12: Combustion chamber 13: Inlet 21: Exhaust gas incinerator main body 22: Insertion pipe 23: Combustion device 24: Ceramics tube 25: Refractory heat insulating material 26: Exhaust gas 27: Treated exhaust gas 28: Fuel 29: Combustion air 30: Fixing tool 31: Outlet 32: Combustion chamber 33: Inlet 41: Ventilation cavity

Claims (1)

An exhaust gas incinerator for directly combusting and treating exhaust gas containing malodorous components and harmful organic components, has an inlet for introducing the exhaust gas into the exhaust gas incinerator, and the inlet is in the exhaust gas incinerator. An exhaust gas incinerator characterized by having an insertion pipe part.

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