WO2000048711A1

WO2000048711A1 - Gas cooling device, gas treatment device, and boiler equipment

Info

Publication number: WO2000048711A1
Application number: PCT/JP2000/000863
Authority: WO
Inventors: Masahiro Izutsu; Yoshitaka Iizuka; Shinji Aoki
Original assignee: Ebara Corporation
Priority date: 1999-02-16
Filing date: 2000-02-16
Publication date: 2000-08-24
Also published as: AU2571500A

Abstract

A gas treatment device which treats sulfur oxides contained in exhaust gas by the combination of these oxides with alkali substances such as ammonia capable of cooling the exhaust gas to a temperature suitable for the combination through a heat exchanger and properly avoiding sulfur oxides contained in the gas from being adhered to heat exchanging surfaces resulting in corrosion, wherein the temperature of at least a part of the heat exchanging surfaces of the heat exchanger is reduced to a moisture saturated temperature or below of the gas, whereby the moisture contained in the gas condenses partly on a part of the heat exchanging surfaces so as to produce condensed water on the surfaces, thus preventing sulphur oxides or soot and dust from adhering to these surfaces, and also a refrigerant cooling the heat exchanging surfaces can produce the generation of condensed water through the entire surfaces of the heat exchanging surfaces by alternately switching refrigerant supply in the forward and reverse directions, and the refrigerant delivered can efficiently utilize waste heat by increasing the temperature to a high temperature of moisture saturated temperature or higher.

Description

Description Gas cooling equipment, gas treatment equipment, and boiler equipment technical field

The present invention relates to gas processing, and more particularly, to a gas cooling device and a gas processing device for removing sulfur oxides contained in boiler combustion gas and the like, and a boiler facility using the same.

Background art

There is known a method for desulfurizing a high-temperature gas containing sulfur oxides such as a boiler combustion gas by using an alkaline substance such as ammonia. One is a method in which a gas containing sulfur oxide is brought into contact with an alkaline aqueous solution containing ammonia or the like, and the sulfur oxide is combined with an alkaline substance to remove the sulfur oxide. Is used to inject ammonia or other alkaline substances into a gas containing sulfur oxides by spraying, etc., irradiate them with an electron beam, convert them into ammonium sulfate powder (as a by-product), and remove them. Method. In either case, desulfurization is performed by combining sulfur oxides with an alkaline substance such as ammonia.However, in order to increase the desulfurization efficiency, it is necessary to cool the gas. Cooling is generally performed by bringing the gas into contact with cooling water and utilizing the heat of evaporation of the cooling water. However, the cooling by evaporation is limited to the water saturation temperature determined by the amount of water contained in the gas, and therefore, the temperature of the gas cannot be lowered sufficiently, so that the desulfurization There were restrictions on increasing the desulfurization rate in the equipment. In short, the cooling by evaporation increases the water content in the gas during the cooling, so that the water saturation temperature rises and the temperature at which the gas can be cooled is limited. More specifically, since gas cooling is performed substantially under adiabatic conditions, the water saturation temperature determined by the evaporation of cooling water performed under the adiabatic conditions, so-called adiabatic cooling water The saturation temperature increases as the temperature of the gas before cooling increases, and as the water concentration of the gas before cooling increases, so that the gas cannot be lowered accordingly. The following table shows an example.

In the case of a wet cooling system in which a high-temperature gas is brought into contact with circulating cooling water to cool the gas, the gas can be cooled almost to the adiabatic cooling water saturation temperature, but the cooling water is sprayed. If water is completely evaporated to prevent drainage, it can only be cooled to a temperature that is typically about 10 ° C higher than the adiabatic cooling water saturation temperature.

Therefore, in order to achieve a high desulfurization rate, it is necessary to find an efficient gas cooling method that can replace the above-mentioned method using the heat of evaporation of cooling water. Further, as described above, in the conventional cooling method, an increase in the water concentration in the gas is inevitable due to the cooling, but ammonia is injected into the gas to recover the ammonia compound powder containing ammonium sulfate in a dry state. For this reason, it is desirable that the powder is as dry as possible at the time of collection. Therefore, the conventional cooling method as described above is not suitable for such a method, especially when the moisture concentration originally contained in the exhaust gas is high. If the temperature before cooling was high, it was difficult to recover in a dry state.

In this respect, it was also desired to improve the gas cooling method. In view of the above, the present invention provides a gas treatment that can cool a high-temperature gas containing sulfur oxides to a required temperature without increasing the moisture concentration in the gas, and achieve a high desulfurization rate. The purpose is to provide equipment, cooling equipment for cooling the equipment, and boiler equipment using them.

In addition, the present invention effectively utilizes heat recovered from gas by gas cooling. It is also intended to be used. Disclosure of the invention

The present invention basically includes a heat exchanger having a heat exchange surface set in a gas flow path, and having a heat exchanger capable of cooling at least a part of the heat exchange surface to a temperature not higher than the moisture saturation temperature of the gas. The present invention provides a gas cooling device characterized by characteristics. This is different from the conventional cooling method using the heat of evaporation described above. It is possible to cool the gas to a required temperature (a temperature lower than the aforementioned adiabatic cooling water saturation temperature) using a heat exchanger. . In addition, on the heat exchange surface, the water content in the gas condenses on the portion where the temperature is lower than the water saturation temperature to generate condensed water. This condensed water prevents sulfur oxides and dust contained in the gas from adhering to the heat exchange surface and corroding the surface, or reducing the heat exchange efficiency.

Further, in this gas cooling device, it is preferable to provide a condensed water collecting device for collecting the condensed water generated on the heat exchange surface so that the collected condensed water can be used. Specifically, the heat exchanger has a storage unit for storing the cooling water, has means for guiding the condensed water recovered by the condensed water recovery device to the storage unit, and is cooled by the heat exchanger. A gas cooler that further cools the gas by bringing the gas into contact with the cooling water can be provided. Further, the heat exchanger has a refrigerant supply device for supplying a refrigerant into the heat exchanger, the device includes a refrigerant flow path for passing a refrigerant for cooling the heat exchange surface, The refrigerant flow path includes a first port for receiving and discharging the refrigerant, and a second port, and the refrigerant supply device supplies the refrigerant to the refrigerant channel from the first port and from the second port. The supply mode of discharging and the supply mode of passing the discharge can be alternately performed. Specifically, the refrigerant supply device sets the temperature of the refrigerant at a temperature for cooling the heat exchange surface to the moisture saturation temperature or lower on the upstream side in the supply direction of the refrigerant, but on the downstream side, Adjust the refrigerant so that it is at or above the water saturation temperature. This By switching the supply direction of the refrigerant, the portion where the moisture saturation temperature occurs on the heat exchange surface changes periodically, and as a result, the generation of condensed water on the entire heat exchange surface is obtained. It is possible to prevent problems such as corrosion of the heat exchange surface due to sulfur oxides and soot in the gas (which can occur without generation of such condensed water) over the entire heat exchange surface. Further, on the downstream side in the refrigerant supply direction, by adjusting the refrigerant so as to have a temperature equal to or higher than the same moisture saturation temperature, utilization of waste heat in the gas can be enhanced. In other words, if the entire heat exchange surface is set to a temperature lower than the water saturation temperature (the water concentration of ordinary boiler exhaust gas is about 5 to 15%, and the water saturation temperature is about 33 to 54 ° C, The temperature of the refrigerant discharged from the heat exchanger is usually from 35 ° C to 55 ° C at the highest, and at such a temperature, it is difficult to use the heat recovered from the gas. is there. In the present invention, as described above, the supply direction of the refrigerant is switched between forward and reverse so that condensed water is generated on the heat exchange surface upstream in the supply direction, and as a result, the heat generated by the condensed water The entire flushing of the exchange surface is performed, and the downstream side in the refrigerant supply direction is adjusted so as to be at or above the water saturation temperature, so that the temperature of the refrigerant discharged from the heat exchanger is reduced. Can be heated to a higher temperature, and waste heat can be used efficiently. Further, it is preferable to provide an apparatus for injecting an alkaline substance such as ammonia into the gas upstream of the heat exchanger in the gas flow path. By doing so, the tendency of the condensed water generated on the heat exchange surface to become acidic due to the dissolution of sulfur oxides can be mitigated. However, by applying a resin material, especially fluorine resin, to the heat exchange surface, it is possible to avoid problems such as corrosion of the heat exchange surface, and in such a case, it is necessary to inject an alkaline substance such as ammonia. The need is particularly eliminated.

The present invention also provides a boiler, and a boiler facility having a boiler combustion exhaust gas flow path, wherein the gas cooling device as described above is installed in the boiler combustion exhaust gas flow path, and heat recovered from the boiler combustion gas by a heat exchanger. A It is a feature to provide boiler equipment to be used for heating the feed water of the boiler. In a boiler facility having a condenser, the heat exchanger is water-cooled, and the condensed water in the condenser is supplied to the heat exchanger as cooling water. Water can be supplied to the boiler to use condensate and waste heat.

The present invention further provides a heat exchange surface set in a flow path of a gas containing a sulfur oxide such as a boiler combustion gas, the heat exchange surface being in contact with the gas, and at least a part of the heat exchange surface is set to a water saturation temperature. A heat exchanger having the following cooling ability; and a desulfurization device that is set downstream of the heat exchange surface in the gas flow path and reacts an alkaline substance with the gas cooled by the heat exchanger to desulfurize the gas. The present invention provides a gas processing apparatus characterized by the above. The efficiency of desulfurization due to the use of alkaline substances can be increased at lower temperatures, and this gas treatment device can efficiently perform desulfurization by lowering the temperature of the gas to the required temperature using a heat exchanger. . The reaction with the alkaline substance is preferably carried out by injecting ammonia into the gas cooled by the heat exchanger. In addition, by providing an electron beam irradiation device for irradiating the gas into which ammonia is injected with an electron beam, it is possible to obtain ammonium sulfate powder produced as a result of the reaction between ammonia and sulfur oxides as a by-product. it can. In this case, since the gas cooled by the heat exchanger has a reduced moisture content, the powder is formed in a much better condition than when the gas is cooled by the conventional cooling method described above. be able to. In this system, the condensed water collected in the condensed water recovery device is added to the condensed water recovery device that collects the condensed water generated on the heat exchange surface, and to the gas into which ammonia is injected after cooling by the heat exchanger. By providing a nozzle for injection, condensed water can be used to suppress the temperature rise due to the heat of reaction of desulfurization with ammonia, and the amount of water discharged as wastewater can be reduced. Further, the desulfurization device may be provided with a desulfurization device that performs desulfurization by bringing the gas cooled by the heat exchanger into contact with a desulfurization solution containing an alkaline substance such as ammonia. In addition, the heat exchanger A refrigerant supply device for supplying a refrigerant into the exchanger, the device having a refrigerant flow passage for passing a refrigerant for cooling a heat exchange surface, the refrigerant flow passage receiving and discharging the refrigerant. A refrigerant supply device that supplies a refrigerant to the refrigerant flow path from the first port and discharges the refrigerant from the second port, and vice versa. Preferably, the supply mode and the supply mode can be alternately performed, and condensed water is generated on the entire heat exchange surface by partially and alternately lowering the heat exchange surface to the moisture saturation temperature or lower. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic configuration diagram showing one embodiment of a gas processing apparatus of the present invention. FIG. 2 is a schematic configuration diagram showing another embodiment of the gas processing apparatus of the present invention. FIG. 3 is a schematic configuration diagram showing still another implementation omission of the gas treatment apparatus of the present invention.

FIG. 4 is a schematic configuration diagram showing another embodiment of the gas processing apparatus of the present invention. FIG. 5 is a schematic configuration diagram showing an example of a boiler facility provided with the gas processing apparatus according to the present invention.

FIG. 6 is a schematic configuration diagram showing one embodiment of a heat exchanger used in the gas processing apparatus according to the present invention.

Fig. 7 is a sectional view taken along the line 7-7 in Fig. 6.

FIG. 8 is a cross-sectional view of a heat exchanger according to another embodiment.

FIG. 9 is a cross-sectional view taken along line 9-1 of FIG.

FIG. 10 is a sectional view taken along line 10-10 of FIG.

FIG. 11 is a sectional view taken along line 11-11 of FIG. Preferred embodiments of the invention

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram of a gas processing apparatus according to the wood invention.

As shown in the figure, this gas treatment device It has an ammonia injector 2 and a heat exchanger 3, which are set in a duct 1 through which high-temperature exhaust gas G containing compounds and the like passes.

The high-temperature exhaust gas G has a water concentration of 150 ° (:, a water concentration of 15 vol%). After the ammonia gas A is injected from the ammonia injector 2, the heat exchanger having the gas contact surface, that is, the heat exchange surface 4 is provided. The cooling water C as cooling soot is passed through the heat exchanger, and the heat exchanging surface 4 is higher than the water saturation temperature (54 ° C) for the above-mentioned water concentration of the exhaust gas. The temperature is kept low at 30 to 40 ° C. Accordingly, the exhaust gas in contact with the heat exchange surface is cooled, and a part of the water contained therein is condensed on the heat exchange surface. When the temperature of the exhaust gas at the outlet of the heat exchanger was adjusted to 60 ° C, the water content became 12 vol%.

Condensed water is generated on the heat exchange surface, and the sulfur oxides that adhere to the heat exchange surface are washed away. Actually, the condensed water generated on the heat exchange surface condenses the sulfur trioxide contained in the exhaust gas to produce dilute sulfuric acid, and the sulfur dioxide in the exhaust gas dissolves in the dilute sulfuric acid, resulting in strong acidity. However, in the example shown in the figure, the ammonia is injected into the exhaust gas by the ammonia injector, so that the injected ammonia also dissolves at the same time, lowering the acidity of the condensed water and improving the cleaning effect. ing. As a result, even if the heat exchange surface of the heat exchanger is made of an inexpensive material such as steel or general-purpose stainless steel, corrosion on the gas contact surface can be suppressed. The condensed water is collected and discharged by a condensed water recovery unit 5 provided at the bottom of the heat exchanger 3. Reference numeral 6 denotes a condensed water pH measuring device 6, which determines the amount of ammonia to be injected into the ammonia injector 2 based on the ph value measured here. The opening of the ammonia flow control valve 7 is adjusted so as to be as follows. Data selected to monitor the pH of the condensate include the pH itself of the condensate, electrical conductivity, specific gravity, ammonium ion concentration, and salt concentration. The setting range for each parameter varies depending on the concentration of sulfur oxides and moisture contained in the high-temperature gas, the type of metal material used for the heat exchange surface of the heat exchanger, etc. Force For example, when the heat exchange surface of the heat exchanger is made of general-purpose stainless steel in boiler combustion exhaust gas, it is preferable to adjust the pH to a range of 2 or more and 7 or less. However, if the properties of the high-temperature gas introduced into the heat exchanger, such as the sulfur oxide and moisture concentration or the temperature, change rapidly in a short period of time, the properties of the condensed water remaining on the gas-contacting surface, There is a possibility that the properties of condensed water that has flowed down from the gas contact surface and collected will have a time lag. For this reason, it is desirable to adjust the amount of ammonia injected by the ammonia injector based on the ammonia concentration in the gas leaving the heat exchanger, which is a faster indicator of the time response. Alternatively, the ammonia injection rate can be adjusted in advance based on the sulfur oxide concentration in the hot gas upstream of the ammonia injector.

FIG. 2 is a schematic configuration diagram showing another embodiment of the gas treatment apparatus of the present invention.

As shown in the figure, this apparatus is significantly different from the apparatus shown in FIG. 1 in that a wet cooler 12 is provided downstream of the heat exchanger. That is, the wet-type cooler 12 is in the form of a tower, and the heat exchanger 3 is installed on the top of the wet-type cooler. The moisture condenses on the heat exchange surface 4 of the heat exchanger 3, and the wet-type cooler 12 The condensed water W that has naturally flown is drawn out from the bottom, pressurized by the circulating water pump 14, and then sprayed into the gas from the circulating water spray device 13 to cool the gas. .

150 after leaving the boiler facility: After injecting ammonia gas 10 from the ammonia injection device 2 into the boiler combustion exhaust gas 8 with a moisture concentration of 15 Vo 1%, it was introduced into the water-cooled heat exchanger 12 Is done. Exhaust gas is treated in the heat exchanger 3 at a temperature of 60: and a water concentration of 12 Vo 1% as in the case of Fig. 1, and then contacted with circulating cooling water 15 in a wet cooler 12 to remove water. It is cooled to the saturation temperature of 54 ° C. The condensed water collected at the bottom of the heat exchanger is extracted from the lower part, pressurized by a circulating water pump 14, and sprayed from a circulating water spraying device 13. Note that the amount of condensed water generated on the heat exchange surface 4 of the heat exchanger is larger than the amount of water evaporated in the wet cooling tower. Part of the condensate is discharged out of the system from the bottom. .

FIG. 3 is a schematic configuration diagram showing another embodiment of the desulfurization apparatus of the present invention. This apparatus has substantially the same configuration as that of FIG. 2, but is collected at the lower part of the wet cooler 16 The difference is that ammonia is injected into the condensed water W through the ammonia diffuser 17, and the gas is cooled and desulfurized. That is, in this device, the wet cooler 16 is a cooling / desulfurization device. The supply of ammonia to the ammonia diffuser 17 can be the same as the ammonia supply (not shown) to the ammonia injector.

The boiler flue gas G that exited the boiler facility had a sulfur oxide concentration of 200 ppm at 150 ° C and a water concentration of 15 vol%, and ammonia gas 10 After being injected, it is introduced into a water-cooled heat exchanger 3, where it is treated to a temperature of 60 ° C and a water concentration of 12 V o 1%. The exhaust gas is further brought into contact with cooling water containing ammonia sprayed by a spraying device 18 in a wet cooler 10 and cooled, and the sulfur oxides react with ammonia to be absorbed into the cooling water. However, the concentration at the gas absorber outlet is reduced to 100 ppm. In addition to the ammonium salt, the cooling water may include, for example, calcium hydroxide and Z or an alkaline substance such as calcium carbonate, magnesium hydroxide, and magnesium carbonate, and a salt of Z or an alkaline substance. A dissolved aqueous solution or slurry can be used.

FIG. 4 shows an example in which the present invention is applied to an apparatus that produces ammonium sulfate powder as a by-product by irradiating an electron beam while reacting ammonia with exhaust gas.

In this device, 2 is an ammonia injector, 3 is a heat exchanger, 21 is a reactor that introduces exhaust gas into the reactor to react with ammonia and irradiates it with an electron beam to produce ammonium sulfate, and 2 2 irradiates with an electron beam The device 24 is an electrostatic precipitator that collects ammonium sulfate powder. The boiler flue gas G leaving the boiler facility is assumed to be 150 ° (with a moisture concentration of 15 Vo 1% and a sulfur oxide concentration of 2000 ppm. After injecting gas A, it is introduced into the water-cooled heat exchanger 3 and treated to 60 ° C and 12 Vo 1% in the heat exchanger as in Figs. 1, 2 and 3 The exhaust gas after the treatment is led to the reaction vessel 21, and the ammonia A mixed with the compressed air P is injected from the two-fluid nozzle 23 at the reaction vessel inlet by the line mixer 27, and then the electron beam irradiation device 2 An electron beam is irradiated by 2. The sulfur oxides contained in the exhaust gas are converted into a by-product powder S containing ammonium sulfate as a main component in the reactor, and the sulfur oxide concentration at the reactor outlet is reduced. 100 ppm The by-product powder S is collected by the electrostatic precipitator 24. The gas contact surface 4 of the heat exchanger 3 The generated condensed water is collected in a condensed water recovery section 5 provided at the bottom of the heat exchanger, mixed with industrial water I in a mixed water tank 25, and the mixed water is mixed with a two-fluid nozzle 23 at the inlet of the reactor. Is sprayed together with a mixed gas of ammonia 10 and compressed air 29.

FIG. 5 shows an example in which the gas processing apparatus of the present invention is applied to a boiler facility.

That is, in this device, the exhaust gas from the boiler 31 passes through the economizer 33 and the air heater 34, and then passes through the ammonia injector 2 and the heat exchanger 3 as in the gas processing device described above. It has become so. The water from the boiler 31 passes through the turbine 32 and is condensed into water in the condenser 35, and is supplied to the heat exchanger 3 as cooling water by the pump 36, and then from the turbine 32. Along with the bleed air, the water is returned to the boiler via the economizer 33 by the boiler feed pump 37. F is fuel, which is heated by the air heater 34 and supplied to the boiler. In this device, the temperature of the boiler feedwater supplied to the boiler can be increased by recovering heat from the exhaust gas in the heat exchanger 3, so that the boiler efficiency can be improved.

6 and 7 show a heat exchanger used in the gas processing apparatus according to the present invention. 2 shows one embodiment of the present invention.

As shown in the figure, the heat exchanger includes a casing 101 incorporated into the exhaust gas duct, and a plurality of heat exchangers (the upper three in the figure, the lower Cooling water pipes (three on each side) (not shown, but it is preferable to use finned pipes that extend radially from the pipe and extend in the longitudinal direction of the pipe in order to increase the heat exchange area). A cooling water supply circuit for supplying cooling water to the cooling water pipe. In FIG. 7, the left side is the upstream side of the gas flow, and the upper and lower side walls on the gas upstream side of the casing have first and second cooling water manifolds 105, respectively. , 106 are provided, and each of the upper and lower cooling water pipes 102 has one end connected to the corresponding upper and lower first manifold, and the other end connected to the second manifold. ing. The upper and lower first manifolds 105 are connected to a first cooling water supply / recovery pipe 112, and the cooling water supply / recovery pipe 112 is connected via an on-off valve 115 (not shown). The upper and lower second manifolds 106 are connected to a second cooling water supply / recovery pipe 1 1 ′, and are connected to the cooling water supply tank. The pipe is connected to a collection tank (not shown) via an on-off valve 118. Between the first and second cooling water supply / recovery pipes 1 1 2 and 1 1 2 ′, bypass pipes 1 1 9 and 1 2 0 having on-off valves 1 1 6 and 1 1 7 are connected, respectively. I have.

In this heat exchanger, the on / off valves 1 1, 1 1, 1 1, 1 1, 1 1 and 1 8 are opened and closed as appropriate to alternately switch the cooling water supply direction between forward direction A and reverse direction B. Can be supplied. That is, if the on-off valves 1 16 and 1 17 are closed and the on-off valves 1 15 and 1 18 are opened, the cooling water is supplied and collected in the forward direction A, and the on-off valves 1 15 and 1 18 When the valve is closed and the other on-off valves 1 16 and 1 17 are opened, it is supplied in the reverse direction B and collected.

Also, in this heat exchanger, the temperature of the cooling water, regardless of the direction in which the cooling water is supplied, depends on the portion of the cooling water pipe 102 on the upstream side at that time. Preferably, the heat exchange surface (the surface of the cooling water pipe) up to the substantially folded portion 102 2 ′ of the cooling water pipe is set to a temperature low enough to cool the gas to the water saturation temperature or lower, On the side, the temperature of the cooling water pipe surface (heat exchange surface) is adjusted to a level that does not lower the temperature to the water saturation temperature. That is, by adjusting the temperature of the cooling water in such a manner, the cooling water condenses on the heat exchange surface in the upstream half of the heat exchange surface in the direction in which the cooling water is supplied, but the downstream half. In this case, condensed water is not generated, and the cooling water passing through this part is heated to a certain temperature by the heat from the gas and discharged. This is because the upstream side in the direction of supply of the cooling water is the force at which the above-mentioned sulfur oxides and the like are washed out by the generation of condensed water.The downstream side does not perform such washing, but instead the cooling water is The purpose of this is to allow the heat to be heated to a certain temperature or higher by the heat from the air, and to make it possible to recover and use the heat from the discharged cooling water. In other words, if the entire surface of the cooling water pipe (heat exchange surface) is to be kept below the water saturation temperature, the cooling water must be kept at a low temperature until it is discharged from the heat exchanger. This is to avoid waste heat recovery and utilization. The above-described flushing of the entire heat exchange surface with condensed water is performed by causing the condensed water to be generated over the entire heat exchange surface by alternately changing the supply direction of the cooling water between the forward and reverse directions A and B. The condensed water collected at the bottom of the casing 101 is discharged through the discharge hole 107, and a part is used as cooling water or the like.

In order to perform heat recovery more efficiently, the cooling water pipe 102 extends downstream from one of the manifolds as shown in the figure, and is turned up at almost the middle portion 102 'of the cooling water pipe and upstream. It is preferred that the shape be such that it returns to the other manifold. This is because, regardless of whether the cooling water flows in the forward or reverse direction, the cooling water is returned to the upstream side of the gas flow in the downstream half at that time, and contacts the warm and insufficiently cooled gas. This is because a large amount of heat can be recovered from the gas.

FIG. 8 shows another embodiment of the heat exchanger. In this heat exchanger, the first and second cooling water manifolds 105, 106 are mounted only on the upper side wall of the casing 101, and on the downstream side of the wall, A relay manifold 110 is provided. The cooling water pipe 102 extends from the first cooling water manifold 105 to the downstream side while meandering up and down, reaches a relay manifold 110, a first portion 102a, and a relay manifold. And a second portion 102 b reaching the second cooling water manifold 106 while meandering up and down from above. As shown in FIG. 11, the relay manifold 110 is divided into three chambers in the width direction of the casing of the heat exchanger, and the first and second portions 102 a, The end of 1102b communicates with each chamber. In the illustrated example, the first and second portions 102a and 102b are each formed so as to protrude outside the casing 101 in a U-shape at the center thereof. This facilitates the setting and maintenance of the cooling water pipe. In this heat exchanger, the control of the supply direction of the cooling water is the same as that in the heat exchanger shown in Figs. 6 and 7, and the state shown in the figure is the force flowing the cooling water in one direction A. It is made to flow in the opposite direction, and the temperature of the cooling water is adjusted similarly.

The heat exchanger as shown in FIGS. 6 and 8 was used as the heat exchanger 3 in the boiler equipment shown in FIG. 5, and the flow rate of the boiler combustion exhaust gas was 100, 00 Nm ³ / h, The concentration was set to 15 vol%, and the same gas exchanged heat with the boiler feed water and fuel Z air in the economizer 33 and the air heater 34, respectively.As a result, the gas was cooled to 150 ° C. While passing through the ammonia injector 2 and the heat exchanger 3, the moisture generated in the boiler 31 is cooled to 30 ° C in the condenser 36 and the heat of the heat exchanger is converted to 10 O ton / h ascites. When used as cooling water, the exhaust gas is cooled to 50 to produce 2.5 ton of condensed water, and at the same time, the cooling water is heated to 75 C, enabling high-efficiency heat recovery. The boiler efficiency was greatly improved.

Industrial applicability According to the present invention, the following effects can be obtained by adopting the above configuration.

When desulfurization is performed by combining exhaust gas containing sulfur oxides such as boiler combustion gas with an alkaline substance such as ammonia, the gas temperature can be reduced to the required temperature suitable for the desulfurization, and it can occur on the heat exchange surface It is possible to wash off the adherence of the conductive sulfur oxide and the like by the condensed water generated on the heat exchange surface.

Further, the cooling medium is supplied into the heat exchanger while alternately switching in the forward and reverse directions, and the temperature of the cooling medium is set so that the heat exchange surface to be cooled by the cooling medium is generally equal to or lower than the moisture saturation temperature. In this case, only the upstream side in the refrigerant supply direction is set to such a temperature, and the downstream side is allowed to reach the above temperature, thereby generating condensed water on the heat exchange surface. The location changes according to the direction of supply of the refrigerant, but as a whole, it can be generated over the entire heat exchange surface, and the temperature of the refrigerant discharged from the heat exchanger is determined by the heat recovered from the gas. The temperature can be raised above a certain level, waste heat recovery from exhaust gas can be effectively performed, and waste heat in boiler equipment and the like can be efficiently used.

Further, if ammonia is injected into the exhaust gas by the ammonia injection device, the ammonia dissolves in the acidic condensed water generated on the gas contacting surface of the heat exchanger, and the ammonia is neutralized, or Since the acidity can be reduced and the corrosion of the gas contact surface can be suppressed, the heat exchange surface of the heat exchanger can be made of inexpensive materials such as steel and general-purpose stainless steel.

Claims

The scope of the claims .

1. A gas cooling device including a heat exchange surface set in a gas flow path and having a heat exchanger capable of cooling at least a part of the heat exchange surface to a temperature equal to or lower than a moisture saturation temperature of the gas.

2. The gas cooling device according to claim 1, further comprising a condensed water recovery device for collecting condensed water generated on the heat exchange surface.

3. A storage unit that is set downstream of the heat exchanger and stores cooling water, and a unit that guides condensed water recovered by the condensed water recovery device to the storage unit. 3. The gas cooling device according to claim 2, further comprising a gas cooler that further cools the cooled gas by bringing the cooled gas into contact with the cooling water.

4. The heat exchanger has a refrigerant supply device for supplying a refrigerant into the heat exchanger, the device includes a refrigerant flow path for passing a refrigerant for cooling the heat exchange surface, The refrigerant flow path includes a first port for receiving and discharging the refrigerant, and a second port, and the refrigerant supply device supplies a refrigerant to the refrigerant flow path from a first port to a second port. 2. The gas cooling device according to claim 1, wherein a supply mode of discharging from the entrance and a supply mode of passing the reverse are alternately performed.

5. The refrigerant supply device sets the temperature of the refrigerant at a temperature for cooling the heat exchange surface to a temperature equal to or lower than the moisture saturation temperature on the upstream side in the supply direction of the refrigerant, but on the downstream side. 5. The gas cooling device according to claim 4, wherein the temperature is adjusted so as to be equal to or higher than the water saturation temperature.

6. A gas injection device, which is set upstream of the heat exchanger in the gas flow path and injects a gaseous substance such as ammonia into the gas. Item 2. A gas cooling device according to item 1.

7. In a boiler and a boiler facility having a boiler flue gas passage, the gas cooling device according to any one of claims 1 to 6 is installed in the boiler flue gas passage, and boiler combustion is performed by the heat exchanger. Times from gas Boiler equipment characterized by utilizing the collected heat for heating boiler feed water

8. A boiler facility having a condenser, wherein the heat exchanger is water-cooled, and the condensed water in the condenser is supplied to the heat exchanger as cooling water. 9. The boiler equipment according to claim 8, wherein the water is supplied to the boiler after the replacement.

9. A heat exchange surface set in the flow path of a gas containing sulfur oxides, such as boiler combustion gas, having a heat exchange surface in contact with the gas, and an ability to cool at least a part of the heat exchange surface to a water saturation temperature or lower. A heat exchanger having

A desulfurization device that is set downstream of a heat exchange surface in the gas flow path and reacts a gaseous substance with the gas cooled by the heat exchanger to desulfurize the gas;

A gas processing device comprising:

10. The gas processing apparatus according to claim 9, wherein the reaction with the alkaline substance is caused by injecting ammonia into the gas cooled by the heat exchanger.

11. The gas processing apparatus according to claim 10, further comprising an electron beam irradiation device for irradiating the gas into which ammonia has been injected with an electron beam.

1 2. A condensed water recovery device that recovers condensed water generated on the heat exchange surface, and a condensed water recovered by the condensed water recovery device is injected into a gas into which the ammonia is injected after cooling by the heat exchanger. The gas processing apparatus according to claim 10, further comprising: a nozzle that performs the processing.

13. The reaction with the alkaline substance is caused by bringing the gas cooled by the heat exchanger into contact with a desulfurization liquid containing an alkaline substance such as ammonia. Gas processing equipment.

14. The storage device according to claim 13, further comprising a storage unit that stores the cooling water, and a unit that guides the condensed water collected by the condensed water recovery device to the storage unit. On-gas processing equipment.

15. The heat exchanger has a refrigerant supply device for supplying a refrigerant into the heat exchanger, and the device has a refrigerant flow path through which a refrigerant for cooling the heat exchange surface passes. A first inlet / outlet for receiving and discharging the refrigerant, and a second inlet / outlet, wherein the refrigerant supply device supplies a refrigerant to the refrigerant flow from the first inlet / outlet, and 14. The gas processing apparatus according to claim 9, 10 or 13, characterized in that a supply mode discharged from the inlet / outlet of (2) and a supply mode passed in the opposite direction can be alternately performed.