JP2017187267A - Boiler anticorrosive device and anticorrosive method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently restrict the boiler blockage caused by the formation of adherence dust layer with low equipment cost and low operation cost while preventing the heat exchanger tube corrosion caused by chloride fused and adhered on a super heater heat exchanger tube of a convection heat transfer chamber of a boiler connected to a waste incinerator.SOLUTION: A boiler 20 that is connected to a waste incinerator 10 for recovering heat from waste gas that comprises: first and second radiation chambers 26 and 28; and a convection heat transfer chamber 30 from the upstream, in which using a pressure wave generation control device 70 for controlling the operation of a pressure wave generation device 61 in which fuel gas is mixed with oxidant gas under high pressure to generate a pressure wave by burning them and discharge the pressure wave into the boiler 20 from a pressure wave discharge nozzle arranged in the second radiation chamber 28, when the exhaust gas temperature measured value measured by exhaust gas temperature meters 71 and 72 at the inlet of the convection heat transfer chamber 30 or the inlet of a most upstream side super heater 34 of the convection heat transfer chamber 30 is a prescribed value or more, the pressure wave is discharged from the pressure wave discharge nozzle.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a boiler corrosion prevention apparatus and corrosion prevention method using chloride melted and fixed to a heat transfer tube of a boiler, and more particularly to a boiler corrosion prevention apparatus and corrosion suitable for use in a waste incineration facility having a power generation facility. It relates to a prevention method.

  In the operation of a waste incineration facility with power generation facilities, maintaining and improving the amount of power generated and sold is one of the most important items after the stable treatment of waste. Power generation at a waste incineration facility is performed by recovering heat from a high-temperature exhaust gas obtained from the combustion of waste in an incinerator and generating steam at a predetermined temperature and pressure and introducing it into a turbine generator. ing. The boiler has a radiant chamber having a radiant heat transfer surface that generates steam by receiving radiant heat from the exhaust gas, a convection heat transfer chamber that generates steam by heat exchange between the exhaust gas and the convective heat transfer surface of the heat transfer tube, and further superheats. It has.

  In the radiant chamber, a radiant heat transfer tube is provided as a radiant heat transfer surface through which heated water is circulated on the outside of the steel side wall surrounding the exhaust gas flow path to generate steam by radiant heating. In the convection heat transfer chamber, a heat transfer tube (also referred to as a superheater) that contacts the exhaust gas in the exhaust gas flow path to generate steam by convective heat transfer and further superheats is disposed as a convection heat transfer surface. The convection heat transfer surface is configured by arranging a plurality of heat transfer tube groups in which a plurality of heat transfer tubes are arranged in the horizontal direction in the height direction. The convection heat transfer chamber may be provided with an economizer having a heat transfer tube that heats water in the exhaust gas flow path to produce heated water. Moreover, in order to heat the water supplied to a boiler in the downstream of a boiler, the separate economizer which has a heat exchanger tube which heats water in an exhaust gas flow path and makes it warm water may be provided in series.

  The exhaust gas generated in refuse incineration contains dust of small particle size including chlorine, sulfur, heavy metals, etc., but if these adhere to the radiant and convective heat transfer surfaces of the boiler, the adhering dust will be Since it acts as a heat insulating material, heat transfer efficiency decreases. Thereby, the heat recovery efficiency also decreases. As a result, the amount of steam generated decreases, and the amount of power generated by the turbine generator decreases. In addition, the gap between the heat transfer tubes may be blocked by adhering dust, which may hinder the flow of exhaust gas.

  For this reason, the equipment which removes adhering dust regularly is needed. As a technique for removing dust adhering to the convection heat transfer surface, a steam soot blower (see Patent Document 1) is known as an apparatus that has a proven record in coal boilers and many boilers. The steam soot blower injects water vapor from a plurality of nozzles toward the heat transfer tube, and peels and removes dust adhering to the surface of the heat transfer tube, and injects water vapor at a regular timing.

JP 2007-183069 A

  The exhaust gas discharged from the waste incinerator contains chloride generated by the reaction between the components contained in the waste and hydrogen chloride in the exhaust gas. Chloride and the like scattered and volatilized from the incinerator adhere to the surface of the superheater heat transfer tube in the convection heat transfer chamber of the boiler connected to the waste incinerator. The melting point of the chloride that is scattered and volatilized varies depending on the composition, but the melting point of a 1: 1 mixed salt of potassium chloride and sodium chloride, which is a typical chloride, is 657 ° C., and the melting point of these two mixed salts is 657 ° C. Is the lowest melting point.

  In a general waste incinerator, since the exhaust gas temperature at the incinerator outlet is 900 ° C. or higher, these chlorides are contained in the exhaust gas in a liquid or gas state and flow into the boiler. The exhaust gas is recovered by heat at the radiant heat transfer surface consisting of water-cooled walls provided in the radiant chamber of the boiler, the temperature drops, and at the entrance of the convection heat transfer chamber where the downstream superheater heat transfer tube group is installed. The exhaust gas temperature is about 600 to 650 ° C. Since the exhaust gas temperature atmosphere at the entrance of the convection heat transfer chamber is below the melting point of the potassium chloride / sodium chloride mixed salt (referred to as chloride), the mixed salt is in a solid state. For this reason, the chloride adhering to the surface of the superheater heat transfer tube does not melt and adhere, but only adheres in the same way as other dust such as fly ash. Thus, the adhering dust on the superheater heat transfer tube surface can be easily removed.

  When the waste incinerator is operated continuously, dust adheres to and accumulates on the water-cooled wall, which is the boiler radiation heat transfer surface. This deposited dust acts as a heat insulating material as the deposition thickness increases, so that the heat recovery ability of the water-cooled wall is lowered and the ability to lower the exhaust gas temperature is lowered. Therefore, the temperature of the exhaust gas flowing into the inlet of the convection heat transfer chamber in which the downstream superheater heat transfer tube group is installed may rise to 650 ° C. or higher.

  Since the melting point of chloride is 657 ° C. or more, the chloride adhering to the surface of the superheater heat transfer tube comes into contact with the exhaust gas higher than the melting point, so that a part of the chloride melts and adheres to the surface of the heat transfer tube. The molten and fixed chloride may not be removed even by a steam soot blower. When other scattered dust adheres to the molten and fixed chloride on these heat transfer tube surfaces, and the thickness of the adhered dust layer formed on the heat transfer tube surface increases with time, the gap between the heat transfer tubes becomes narrower and the boiler The risk of becoming blocked becomes increased. Moreover, when the adhesion dust layer thickness on the superheater heat transfer tube surface increases, the heat recovery capability of the superheater heat transfer tube decreases.

  Further, when chloride contained in the exhaust gas adheres to the surface of the superheater heat transfer tube and a part thereof melts, corrosion of the heat transfer tube and thickness reduction occur due to the action of chlorine in the chloride on the surface of the superheater heat transfer tube. When the heat transfer tube is corroded or thinned and exceeds the amount of thinning required by law, it is necessary to replace the superheater heat transfer tube. Replacement of this superheater heat transfer tube is very expensive, and as a countermeasure against this, the thickness of the superheater heat transfer tube can be reduced by spraying or overlaying a corrosion resistant metal material such as Inconel or Hastelloy on the surface of the superheater heat transfer tube. It is reduced. However, the thermal spraying and overlaying of the corrosion-resistant metal material also requires a large amount of money, which increases the equipment cost of the waste power generation facility.

  The present invention has been made in view of the situation as described above, and is a heat transfer tube formed by chloride melted and fixed to a superheater heat transfer tube in a convection heat transfer chamber in a boiler connected to a waste incinerator. It is an object of the present invention to provide a corrosion prevention device and a corrosion prevention method for a boiler that can efficiently prevent corrosion of the boiler and prevent boiler blockage caused by the formation of an adhering dust layer with low equipment costs and operating costs. It is.

  Table 1 shows the composition, compound form, and exhaust gas temperature at the inlet of the convection heat transfer chamber, which were clarified by collecting and analyzing the dust attached to the surface of the superheater heat transfer tube at an actual waste incineration facility.

  When the exhaust gas temperature at the inlet of the convection heat transfer chamber is higher than 650 ° C. as in the waste incineration facilities A and B, the composition of adhering dust on the superheater heat transfer tube surface is high in Cl, low in S, and the chemical form of the main compound is The chlorides were KCl and NaCl.

  On the other hand, in the waste incineration facility C, a pressure wave generator is installed in the second radiation chamber to separate and remove dust adhering to the radiation heat transfer surface to prevent a decrease in heat recovery efficiency due to dust adhesion. The heat recovery from the exhaust gas was performed steadily, and the exhaust gas temperature at the inlet of the convection heat transfer chamber was maintained at 650 ° C. or lower. In this case, the composition of the adhering dust on the surface of the superheater heat transfer tube was low in Cl and high in S, and the form of the main compound was K and Na sulfate. The waste incineration facility D does not include a pressure wave generator, but the exhaust gas temperature is relatively low and the convection heat transfer chamber inlet temperature is 650 ° C. or lower. In this case, the waste incineration facility C is similar to the waste incineration facility C. It was a result.

  Using the adhering dust collected from these four waste incineration facilities, a corrosion test was conducted on the same material as the superheater heat transfer tube. As shown in Table 1, dust containing chloride is highly corrosive, and sulfuric acid The result was that the dust containing the chemicals was less corrosive.

  In the waste incineration facility C, a pressure wave generator was installed in the second radiation chamber to remove and remove dust adhering to the radiant heat transfer surface. Instead of the pressure wave generator, a water injection nozzle was inserted from the top of the boiler. The same result was obtained even when a water jet device that jets liquid water onto the water cooling wall in the second radiation chamber to remove the adhering dust was used.

  A pressure wave generator or water jetting device is installed in the second radiation chamber to peel off and remove dust adhering to the radiant heat transfer surface to prevent a decrease in heat recovery efficiency due to dust adhesion, and heat from exhaust gas in the second radiation chamber. The reason why the inventors have studied the reason why such a result can be obtained by steadily collecting and maintaining the exhaust gas temperature at the inlet of the convection heat transfer chamber at 650 ° C. or lower will be described below.

The exhaust gas flowing through the boiler of the waste incineration facility contains sulfur oxide SOx. This SOx reacts with chloride K (Na) Cl adhering to the surface of the superheater heat transfer tube in the boiler together with O ₂ , H ₂ O and the like contained therein to convert the sulfate K (Na) ₂ SO ₄ Generate.
2K (Na) Cl + SO ₂ + 1 / 2O ₂ + H ₂ O → K (Na) ₂ SO ₄ + 2HCl (1)

  On the surface of the superheater heat transfer tube of the boiler of the waste incineration facility, the reaction in which the sulfate is generated from the chloride proceeds easily in a temperature atmosphere of 650 ° C. or less. At a temperature higher than 650 ° C., the molten chloride coats the surface of the adhering dust layer, and it is difficult for SOx or the like in the exhaust gas to reach the inside of the dust layer even if sulfate is generated on the surface of the dust layer. 1) The reaction of the formula is difficult to proceed.

  In addition, when the exhaust gas temperature at the inlet of the convection heat transfer chamber is higher than 650 ° C., chloride melts and adheres, so that even if the steam soot blower is operated in the convection heat transfer chamber, the dust on the superheater heat transfer tube surface, It becomes difficult to completely remove dust adhering to the surface of the superheater heat transfer tube in the gap between the heat tubes. Then, the thickness of the dust layer remaining on the surface of the superheater heat transfer tube increases, and the reaction between chloride in the dust layer and SOx contained in the exhaust gas is further inhibited, and the reaction to the sulfur oxide does not proceed.

  On the other hand, when the exhaust gas temperature at the convection heat transfer chamber inlet is 650 ° C. or less, the reaction in which the chloride in the dust adhering to the heat transfer tube surface reacts with SOx and the like to generate a sulfate proceeds, Chloride does not melt and adhere to the surface of the heat transfer tube, and it is possible to satisfactorily remove dust adhering to the surface of the superheater heat transfer tube with a steam soot blower. Therefore, the increase in the dust layer thickness on the superheater heat transfer tube surface is suppressed, and since there is no coating of the dust layer surface by melting of chloride, SOx in the exhaust gas can easily enter the dust layer, and sulfuric acid Reaction to the compound proceeds. And since it can prevent that a chloride melts | dissolves and adheres to the superheater heat exchanger tube surface, corrosion and thickness reduction of the heat exchanger tube by chloride can be suppressed.

  By maintaining the exhaust gas temperature at the inlet of the convection heat transfer chamber at 650 ° C. or less, chloride can be prevented from melting and sticking to the superheater heat transfer tube surface of the convection heat transfer chamber. It became clear that thinning can be suppressed. In addition, it is possible to satisfactorily remove adhering dust on the surface of the superheater heat transfer tube using a steam soot blower.

  In order to maintain the exhaust gas temperature at the convection heat transfer chamber inlet at 650 ° C. or lower, a pressure wave generator or a water injection device is installed in the second radiation chamber to separate and remove dust adhering to the radiation heat transfer surface. It is preferable to prevent a decrease in heat recovery efficiency due to, and steadily recover heat from the exhaust gas in the second radiation chamber. Accordingly, it is possible to steadily maintain the exhaust gas temperature at the convection heat transfer chamber inlet at 650 ° C. or lower.

  Although the exhaust gas temperature at the convection heat transfer chamber inlet is maintained at 650 ° C. or lower, the preferable upper limit value of the exhaust gas temperature at the convection heat transfer chamber inlet may be the melting point of chloride generated from waste. Good. The composition of the chloride produced by the composition of the waste is affected and the melting point is also affected, but the melting point can be determined by examining the composition of the chloride produced beforehand.

  When a screen tube and a superheater are installed in the convection heat transfer chamber from the upstream side, the exhaust gas is cooled by the screen tube, and the exhaust gas temperature at the uppermost stream superheater inlet becomes the temperature at the convection heat transfer chamber inlet. Compared to 50 ° C. Therefore, instead of maintaining the exhaust gas temperature at the convection heat transfer chamber inlet at 650 ° C. or lower, the exhaust gas temperature at the most upstream superheater inlet of the convection heat transfer chamber may be maintained at 600 ° C. or lower. By maintaining the exhaust gas temperature at the uppermost stream side superheater inlet of the convection heat transfer chamber at 600 ° C or less, it is possible to prevent chloride from melting and sticking to the surface of the superheater heat transfer tube in the convection heat transfer chamber. It is possible to suppress corrosion and thinning of the heat transfer tube. In addition, it is possible to satisfactorily remove adhering dust on the surface of the superheater heat transfer tube using a steam soot blower.

  The exhaust gas temperature at the entrance of the convection heat transfer chamber can react with corrosive dust represented by chloride adhering to the surface of the superheater heat transfer tube to react with SOx etc. and convert it into low corrosive dust. By setting the temperature atmosphere, corrosion and thinning of the superheater heat transfer tube can be prevented.

  Also, instead of removing dust adhering to the superheater heat transfer tube surface with a steam soot blower in the convection heat transfer chamber, a pressure wave generator is also installed in the convection heat transfer chamber, and dust removal operation is performed every 1 to 3 hours. More preferably. Compared with a steam soot blower that operates every 12 to 24 hours, the pressure wave generator that operates every 1 to 3 hours can reduce the thickness of the dust layer on the surface of the superheater heat transfer tube. Then, SOx or the like in the exhaust gas easily enters the dust layer, and the reaction to the sulfate easily proceeds. Moreover, since the adhesion amount of the chloride which should be converted into a sulfate can be reduced, the effect is further increased.

  The present invention has been made on the basis of the above-described investigation results, and is connected to a waste incinerator and is divided by two turning portions that bend the flow path of the exhaust gas for heat recovery from the exhaust gas. From the side, heat is generated by heat exchange between the first and second radiant chambers having a radiant heat transfer surface that generates radiant heat from the exhaust gas and the convection heat transfer surface of the heat transfer tube. A boiler having a convection heat transfer chamber having a superheater that further superheats, the boiler corrosion prevention device for preventing corrosion of the heat transfer tube due to dust adhering to the heat transfer tube of the convection heat transfer chamber, comprising fuel gas and oxidation A pressure wave generator that mixes and burns the agent gas under high pressure to generate a pressure wave and discharges the pressure wave into the boiler is provided, and a pressure wave discharge nozzle of the pressure wave generator is disposed in the second radiation chamber. At the entrance of the convection heat transfer chamber. An exhaust gas thermometer for measuring the pressure wave generation control device for controlling the operation of the pressure wave generation device, the pressure wave generation control device is an exhaust gas temperature measurement value at the convection heat transfer chamber inlet by the exhaust gas thermometer When the pressure wave is equal to or greater than a predetermined value, the pressure wave generator is controlled so as to discharge a pressure wave from the pressure wave discharge nozzle.

  Here, the pressure wave generation control device controls the pressure wave generation device to emit a pressure wave from the pressure wave generation nozzle when the measured exhaust gas temperature at the convection heat transfer chamber inlet is 650 ° C. or more. Can be controlled.

  The present invention also receives radiant heat from the exhaust gas from the upstream side, which is divided by two turning portions that are connected to a waste incinerator and bends the flow path of the exhaust gas for heat recovery from the exhaust gas. Convection transfer having first and second radiation chambers having radiation heat transfer surfaces for generating steam and a superheater that generates steam by heat exchange between the exhaust gas and the convection heat transfer surface of the heat transfer tube and further superheats A boiler equipped with a heat chamber, which prevents corrosion of the heat transfer tube due to dust adhering to the heat transfer tube of the convection heat transfer chamber, and mixes and burns fuel gas and oxidant gas under high pressure. A pressure wave generator for generating a pressure wave and releasing the pressure wave into the boiler, and a pressure wave discharge nozzle of the pressure wave generator is disposed in the second radiation chamber, and the convection heat transfer chamber Exhaust gas temperature at which the exhaust gas temperature is measured at the most upstream superheater inlet And a pressure wave generation control device for controlling the operation of the pressure wave generation device, the pressure wave generation control device is configured to measure the exhaust gas temperature at the most upstream superheater inlet of the convection heat transfer chamber by an exhaust gas thermometer. When the value is equal to or greater than a predetermined value, the problem is similarly solved by controlling the pressure wave generator so as to emit a pressure wave from the pressure wave discharge nozzle.

  Here, the pressure wave generation control device emits a pressure wave from the pressure wave discharge nozzle when the measured exhaust gas temperature at the most upstream superheater inlet of the convection heat transfer chamber is 600 ° C. or more. The pressure wave generator can be controlled.

  The present invention also receives radiant heat from the exhaust gas from the upstream side, which is divided by two turning portions that are connected to a waste incinerator and bends the flow path of the exhaust gas for heat recovery from the exhaust gas. Convection transfer having first and second radiation chambers having radiation heat transfer surfaces for generating steam and a superheater that generates steam by heat exchange between the exhaust gas and the convection heat transfer surface of the heat transfer tube and further superheats A boiler equipped with a heat chamber, which prevents corrosion of the heat transfer tube due to dust adhering to the heat transfer tube of the convection heat transfer chamber, wherein water is injected to the water cooling wall in the second radiation chamber. A water injection device for removing adhering dust, an exhaust gas thermometer for measuring an exhaust gas temperature at an inlet of the convection heat transfer chamber, and a water injection control device for controlling the operation of the water injection device, the water injection control device At the entrance of the convection heat transfer chamber by the exhaust gas thermometer When the exhaust gas temperature measurement value is a predetermined value or more, by controlling so as to inject water from the water injector is obtained by solving the above problems as well.

  Here, the water injection control device can control to inject water from the water injection device when the measured exhaust gas temperature at the convection heat transfer chamber inlet is 650 ° C. or more.

  The present invention also receives radiant heat from the exhaust gas from the upstream side, which is divided by two turning portions that are connected to a waste incinerator and bends the flow path of the exhaust gas for heat recovery from the exhaust gas. Convection transfer having first and second radiation chambers having radiation heat transfer surfaces for generating steam and a superheater that generates steam by heat exchange between the exhaust gas and the convection heat transfer surface of the heat transfer tube and further superheats A boiler equipped with a heat chamber, which prevents corrosion of the heat transfer tube due to dust adhering to the heat transfer tube of the convection heat transfer chamber, wherein water is injected to the water cooling wall in the second radiation chamber. A water injection device that removes adhering dust, an exhaust gas thermometer that measures the exhaust gas temperature at the most upstream superheater inlet of the convection heat transfer chamber, and a water injection control device that controls the operation of the water injection device, The water injection control device is provided with the exhaust gas thermometer. When the exhaust gas temperature measurement value at the inlet of the most upstream superheater of the heat transfer chamber is equal to or greater than a predetermined value, the above problem is similarly solved by controlling the water injection device to inject water. .

  Here, the water injection control device controls the water injection device to inject water when the measured exhaust gas temperature at the most upstream superheater inlet of the convection heat transfer chamber is 600 ° C. or more. Can do.

  The present invention also receives radiant heat from the exhaust gas from the upstream side, which is divided by two turning portions that are connected to a waste incinerator and bends the flow path of the exhaust gas for heat recovery from the exhaust gas. Convection transfer having first and second radiation chambers having radiation heat transfer surfaces for generating steam and a superheater that generates steam by heat exchange between the exhaust gas and the convection heat transfer surface of the heat transfer tube and further superheats A boiler equipped with a heat chamber, which prevents corrosion of the heat transfer tube due to dust adhering to the heat transfer tube of the convection heat transfer chamber, and is a method of mixing fuel gas and oxidant gas under high pressure and burning. The pressure wave generation control device that controls the operation of the pressure wave generation device that generates a pressure wave and discharges the pressure wave from the pressure wave discharge nozzle disposed in the second radiation chamber into the boiler, Exhaust gas at the convection heat transfer chamber inlet When degree measurement value is a predetermined value or more, there is provided a corrosion prevention method of the boiler, characterized by controlling the pressure wave generator to emit a pressure wave from the pressure wave discharge nozzle.

  Here, when the exhaust gas temperature measurement value at the inlet of the convection heat transfer chamber is 650 ° C. or higher, the pressure wave generation control device is used to release the pressure wave from the pressure wave discharge nozzle. The device can be controlled.

  The present invention also receives radiant heat from the exhaust gas from the upstream side, which is divided by two turning portions that are connected to a waste incinerator and bends the flow path of the exhaust gas for heat recovery from the exhaust gas. Convection transfer having first and second radiation chambers having radiation heat transfer surfaces for generating steam and a superheater that generates steam by heat exchange between the exhaust gas and the convection heat transfer surface of the heat transfer tube and further superheats A boiler equipped with a heat chamber, which prevents corrosion of the heat transfer tube due to dust adhering to the heat transfer tube of the convection heat transfer chamber, and is a method of mixing fuel gas and oxidant gas under high pressure and burning. The pressure wave generation control device that controls the operation of the pressure wave generation device that generates a pressure wave and discharges the pressure wave from the pressure wave discharge nozzle disposed in the second radiation chamber into the boiler, Of the convection heat transfer chamber measured by a meter Provided is a boiler corrosion prevention method for controlling the pressure wave generator so as to discharge a pressure wave from the pressure wave discharge nozzle when an exhaust gas temperature measurement value at an inlet is a predetermined value or more. It is.

  Here, using the pressure wave generation control device, when the exhaust gas temperature measurement value at the most upstream superheater inlet of the convection heat transfer chamber is 600 ° C. or more, the pressure wave is discharged from the pressure wave discharge nozzle. Thus, the pressure wave generator can be controlled.

  The present invention also receives radiant heat from the exhaust gas from the upstream side, which is divided by two turning portions that are connected to a waste incinerator and bends the flow path of the exhaust gas for heat recovery from the exhaust gas. First and second radiant chambers having radiant heat transfer surfaces for generating steam and convection heat transfer chambers having a superheater that generates steam by heat exchange between the exhaust gas and the convective heat transfer surface of the heat transfer tube and further superheats And a boiler equipped with an economizer for heating water supplied to the boiler by heat exchange between the exhaust gas and the convection heat transfer surface of the heat transfer tube, and corrosion of the heat transfer tube due to dust adhering to the convection heat transfer chamber and the economizer heat transfer tube An exhaust gas thermometer using a water injection control device that controls the operation of a water injection device that injects water onto a water cooling wall in the second radiation chamber to remove adhering dust. Convection heat transfer measured by When the exhaust gas temperature measurements at the inlet is higher than a predetermined value, there is provided a corrosion prevention method of boiler and controls so as to inject water.

  Here, when the exhaust gas temperature measurement value at the inlet of the convection heat transfer chamber is 650 ° C. or higher, the water injection control device can be used to control to inject water from the water injection device.

  The present invention also receives radiant heat from the exhaust gas from the upstream side, which is divided by two turning portions that are connected to a waste incinerator and bends the flow path of the exhaust gas for heat recovery from the exhaust gas. First and second radiant chambers having radiant heat transfer surfaces for generating steam and convection heat transfer chambers having a superheater that generates steam by heat exchange between the exhaust gas and the convective heat transfer surface of the heat transfer tube and further superheats And a boiler equipped with an economizer for heating water supplied to the boiler by heat exchange between the exhaust gas and the convection heat transfer surface of the heat transfer tube, and corrosion of the heat transfer tube due to dust adhering to the convection heat transfer chamber and the economizer heat transfer tube An exhaust gas thermometer using a water injection control device that controls the operation of a water injection device that injects water onto a water cooling wall in the second radiation chamber to remove adhering dust. Convection heat transfer measured by When exhaust gas temperature measurements at the most upstream side superheater inlet of a predetermined value or more, there is provided a corrosion prevention method of boiler and controls so as to inject water.

  Here, when the exhaust gas temperature measurement value at the most upstream superheater inlet of the convection heat transfer chamber is 600 ° C. or higher, the water injection control device is used to control to inject water from the water injection device. can do.

  According to the present invention, it is possible to prevent corrosion of the heat transfer tube caused by chloride that melts and adheres to the superheater heat transfer tube of the convection heat transfer chamber in the boiler, and to suppress the blockage of the boiler caused by the formation of the adhered dust layer. Efficient and cost-effective corrosion-resistant metal materials can be sprayed and built-up without low-cost equipment and operating costs, making it possible to operate an economically advantageous and stable waste incineration facility Become.

Sectional drawing which shows the structure of 1st Embodiment of this invention. Sectional drawing which shows the structure of 2nd Embodiment of this invention. Sectional drawing which shows the structure of 3rd Embodiment of this invention. Sectional drawing which shows the structure of 4th Embodiment of this invention. Sectional drawing which shows the structure of 5th Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by the content described in the following embodiment and an Example. In addition, the constituent elements in the embodiments and examples described below include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in the so-called equivalent range. Furthermore, the constituent elements disclosed in the embodiments and examples described below may be appropriately combined or may be appropriately selected and used.

  First, a boiler connected to a waste incinerator to which the present invention is applied will be described. As shown in FIG. 1, a boiler 20 connected to an incinerator 10 for recovering heat from exhaust gas is divided by two turning portions 21 and 22 that bend the exhaust gas flow passage, and upstream of the exhaust gas flow direction. The first radiation chamber 26, the second radiation chamber 28, and the convection heat transfer chamber 30 are provided. A gas mixing chamber 24 is provided in the vicinity of the inlet of the first radiation chamber 26 that receives exhaust gas from the incinerator 10. The exhaust gas introduced from the incinerator 10 flows from the lower side of the first radiation chamber 26 to the upper side, from the upper side to the lower side of the second radiation chamber 28, and from the lower side to the upper side of the convection heat transfer chamber 30.

  The first radiation chamber 26 and the second radiation chamber 28 are each provided with a radiation heat transfer surface that generates radiant heat from the exhaust gas and generates steam.

  The convection heat transfer chamber 30 includes a screen tube 32, a secondary superheater 34, a tertiary superheater 36, a primary superheater 38, and a second economizer 42 from the upstream side in the exhaust gas flow direction. Each of the secondary superheater 34, the tertiary superheater 36, and the primary superheater 38 includes a heat transfer tube group in which a plurality of heat transfer tubes arranged in a horizontal direction are provided in multiple stages in the height direction. A convection heat transfer surface is formed, and steam is generated by heat exchange with the exhaust gas to further overheat. The screen tube 32 is provided with a heat transfer tube in the shape of a flag to cool the exhaust gas introduced into the convection heat transfer chamber 30.

  In order to carry out the present invention, in the first embodiment of the present invention, the corrosion prevention of the boiler which prevents corrosion and thinning of the heat transfer tube of the boiler 20 due to chloride melted and fixed to the heat transfer tube of the convection heat transfer chamber 30. As a device, there is provided a pressure wave generator 61 that mixes fuel gas and oxidant gas under high pressure and burns them to generate a pressure wave and release the pressure wave into the second radiation chamber 28 of the boiler 20. A pressure wave discharge nozzle (not shown) of the device 61 is disposed in the second radiation chamber 28.

  One pressure wave discharge nozzle is disposed at an intermediate position in the height direction of at least the second radiation chamber 28.

  In the present embodiment, as a more preferable form, the convection heat transfer chamber 30 is also provided with pressure wave discharge nozzles (not shown) of the pressure wave generators 62 and 63, which are respectively connected to the screen tube 32 and the secondary superheater. Between the heat exchanger 34 and between the tertiary superheater 36 and the primary superheater 38. Further, pressure wave discharge nozzles can be attached to manholes (not shown) provided at these positions.

  In order to control the pressure wave emitted from the pressure wave discharge nozzle of the pressure wave generator 61 disposed in the second radiation chamber 28, the exhaust gas temperature at the inlet of the convection heat transfer chamber 30 or the outlet of the second radiation chamber 28 is measured. An exhaust gas thermometer 71 and a pressure wave generation control device 70 for controlling the operation of the pressure wave generation device 61. In the pressure wave generation control device 70, an exhaust gas temperature measurement value by the exhaust gas thermometer 71 is a predetermined value, for example, When the temperature is 650 ° C. or higher, the pressure wave generator 61 is controlled so as to emit a pressure wave from the pressure wave discharge nozzle.

  The pressure wave generator 61 fills and mixes a fuel gas (for example, methane gas) and an oxidant gas (for example, oxygen gas) in the mixed gas holder under high pressure, and mixes the gas according to instructions given from the pressure wave generation control device 70. Is ignited with a spark plug and exploded and burned to generate a pressure wave. The pressure in the mixed gas holder during the explosion combustion reaches, for example, a maximum of 53.2 bar. Thereby, a pressure wave is emitted into the second radiation chamber 28 from the tip of the pressure wave discharge nozzle disposed in the second radiation chamber 28 of the boiler 20. Thus, vibration and wind pressure are applied to the radiation heat transfer surface of the second radiation chamber 28, and the attached dust is peeled off and removed.

  In the present embodiment, since the pressure wave generators 62 and 63 are also disposed in the convection heat transfer chamber 30, dust attached to the convection heat transfer surface of the convection heat transfer chamber 30 is also removed.

  The range in which the pressure wave discharged from the pressure wave discharge nozzle gives vibration and wind pressure to the extent that the adhering dust is separated from the convection heat transfer surface is about 3.5 m upward and downward from the pressure wave discharge nozzle. . Therefore, it is preferable to set the height direction disposition interval of the pressure wave discharge nozzles in the convection heat transfer chamber 30 to 7 m or less, and a gap is formed between the adjacent range and the range in which the adhered dust is separated. Can be provided. Furthermore, it is preferable that the height wave interval between the pressure wave discharge nozzles is 3 m or more, and the pressure waves discharged from the adjacent pressure wave discharge nozzles interfere with each other, and the adhesion of the pressure wave discharge nozzles is not reduced. Dust can be reliably peeled off. Thus, in order to give sufficient vibration and wind pressure to the heat transfer tube group of the convection heat transfer chamber 30, it is preferable that the arrangement interval of the pressure wave discharge nozzles in the height direction is 3 m or more and 7 m or less.

  As in the second embodiment shown in FIG. 2, an exhaust gas thermometer 72 is provided at the inlet of the superheater 34 on the most upstream side (lowermost in the drawing) of the convection heat transfer chamber 30, and the pressure wave generation control device 70. The exhaust gas temperature measurement value at the inlet of the uppermost stream superheater 34 of the convection heat transfer chamber 30 detected by the exhaust gas thermometer 72 is a predetermined value, for example, 50 ° C. lower than the predetermined value of the first embodiment, for example, When the temperature is 600 ° C. or higher, the pressure wave can be controlled to be discharged from the pressure wave discharge nozzles of the pressure wave generators 61 to 63.

  Next, as shown in FIG. 3, a third embodiment of the present invention applied when a separate economizer 50 is attached downstream of the boiler 20 will be described. In the present embodiment, a separate economizer 50 is connected to the downstream side of the boiler 20, and a first economizer 51 is disposed in the separate economizer 50. The first economizer 51 of the separate economizer 50 and the second economizer 42 of the convection heat transfer chamber 30 are provided with heat transfer tubes, and water is heated by heat exchange with the exhaust gas to generate heated water, which is supplied to the boiler 20. The

  In the present embodiment, as shown in FIG. 3, generation of a pressure wave that mixes fuel gas and oxidant gas under high pressure and burns them to generate a pressure wave and release the pressure wave into the boiler 20 and the first economizer 51. The devices 61 to 64 are provided, and the pressure wave discharge nozzles of the pressure wave generators 61 to 64 are disposed in the second radiation chamber 28, the convection heat transfer chamber 30, and the separate economizer 50.

  An exhaust gas thermometer 71 that measures the exhaust gas temperature at the inlet of the convection heat transfer chamber 30 or the outlet of the second radiation chamber 28 and a pressure wave generation control device 70 that controls the operation of the pressure wave generator 61 are provided. The generation control device 70 performs control so as to release a pressure wave from the pressure wave discharge nozzle of the pressure wave generator 61 when the exhaust gas temperature measurement value by the exhaust gas thermometer 71 is a predetermined value, for example, 650 ° C. or more.

  In the third embodiment, one pressure wave generator controlled by the pressure wave generation controller 70 is disposed in the second radiation chamber 28, and two pressure wave generators are separately provided in the convection heat transfer chamber 30. Although at least one of the separate economizers 50 is disposed, the position and number of the pressure wave generators are not limited to this, and the pressure wave generators of the separate economizer 50 may be omitted or convection heat transfer may be performed. One pressure wave generator may be disposed in the chamber 30.

  In each of the first to third embodiments, a pressure wave discharge nozzle is installed in the second radiation chamber 28 to remove and remove dust adhering to the radiation heat transfer surface. For example, FIG. As shown in the fourth embodiment (corresponding to the first embodiment) shown in FIG. 5 or the fifth embodiment (corresponding to the second embodiment) shown in FIG. You may use the water injection apparatus 80 which inserts and injects water on the water cooling wall in the 2nd radiation chamber 28, and removes adhering dust.

  The water jetted from the water jet nozzle 81 has a predetermined exhaust gas temperature measured by an exhaust gas thermometer 71 (fourth embodiment) or 72 (fifth embodiment), for example, 650 ° C. (fourth embodiment). Or it is controlled by the water injection control device 82 so that it is injected when the temperature is 600 ° C. (the fifth embodiment) or higher.

  In the fourth and fifth embodiments, the pressure wave generators 62 and 63 similar to those in the first to third embodiments are also provided, so that the adhering dust in the convection heat transfer chamber 30 can also be removed. Note that these may be omitted and only water injection into the second radiation chamber 28 may be performed.

  In the first, third, and fourth embodiments, only the exhaust gas thermometer 71 is provided, and in the second and fifth embodiments, only the exhaust gas thermometer 72 is provided. However, both the exhaust gas thermometers 71 and 72 are provided. The operation can be ensured.

  In the above description, the present invention is applied to a boiler connected to a municipal waste incinerator, but the application target of the present invention is not limited to this.

DESCRIPTION OF SYMBOLS 10 ... Incinerator 20 ... Boiler 21, 22 ... Turning part 26 ... 1st radiation chamber 28 ... 2nd radiation chamber 30 ... Convection heat transfer chamber 32 ... Screen tube 34 ... Secondary superheater 36 ... Tertiary superheater 38 ... Primary superheater 42 ... second economizer 50 ... separate economizer 51 ... first economizer 61, 62, 63, 64 ... pressure wave generator 70 ... pressure wave generator controller 71, 72 ... exhaust gas thermometer 80 ... water injection device 81 ... Water injection nozzle 82 ... Water injection control device

Claims (16)

Radiation that generates steam by receiving radiant heat from the exhaust gas from the upstream side, separated by two turning sections that bend the flow path of the exhaust gas, connected to the waste incinerator to recover heat from the exhaust gas A boiler having first and second radiation chambers having heat transfer surfaces, and a convection heat transfer chamber having a superheater that generates steam by heat exchange between the exhaust gas and the convection heat transfer surface of the heat transfer tube and further superheats. A boiler corrosion prevention device for preventing corrosion of the heat transfer tube due to dust adhering to the heat transfer tube of the convection heat transfer chamber,
A pressure wave generator is provided that mixes fuel gas and oxidant gas under high pressure and burns to generate a pressure wave and discharge the pressure wave into the boiler. The pressure wave discharge nozzle of the pressure wave generator includes the second While arranged in the radiation chamber,
An exhaust gas thermometer that measures the exhaust gas temperature at the inlet of the convection heat transfer chamber, and a pressure wave generation control device that controls the operation of the pressure wave generation device,
The pressure wave generation control device controls the pressure wave generation device to emit a pressure wave from the pressure wave discharge nozzle when the exhaust gas temperature measurement value at the convection heat transfer chamber inlet by the exhaust gas thermometer is equal to or greater than a predetermined value. A boiler corrosion prevention device characterized by controlling.   The pressure wave generation control device controls the pressure wave generation device so as to emit a pressure wave from the pressure wave discharge nozzle when a measured value of exhaust gas temperature at the inlet of the convection heat transfer chamber is 650 ° C. or more. The boiler corrosion prevention apparatus according to claim 1. Radiation that generates steam by receiving radiant heat from the exhaust gas from the upstream side, separated by two turning sections that bend the flow path of the exhaust gas, connected to the waste incinerator to recover heat from the exhaust gas A boiler having first and second radiation chambers having heat transfer surfaces, and a convection heat transfer chamber having a superheater that generates steam by heat exchange between the exhaust gas and the convection heat transfer surface of the heat transfer tube and further superheats. A boiler corrosion prevention device for preventing corrosion of the heat transfer tube due to dust adhering to the heat transfer tube of the convection heat transfer chamber,
A pressure wave generator is provided that mixes fuel gas and oxidant gas under high pressure and burns to generate a pressure wave and discharge the pressure wave into the boiler. The pressure wave discharge nozzle of the pressure wave generator includes the second While arranged in the radiation chamber,
An exhaust gas thermometer that measures the exhaust gas temperature at the most upstream superheater inlet of the convection heat transfer chamber, and a pressure wave generation control device that controls the operation of the pressure wave generation device,
The pressure wave generation control device emits a pressure wave from the pressure wave discharge nozzle when the exhaust gas temperature measurement value at the most upstream superheater inlet of the convection heat transfer chamber by the exhaust gas thermometer is a predetermined value or more. An apparatus for preventing corrosion of a boiler, characterized by controlling the pressure wave generator.   The pressure wave generation control device is configured to release the pressure wave from the pressure wave discharge nozzle when the measured exhaust gas temperature at the most upstream superheater inlet of the convection heat transfer chamber is 600 ° C. or more. The boiler corrosion prevention apparatus according to claim 3, wherein the generator is controlled. Radiation that generates steam by receiving radiant heat from the exhaust gas from the upstream side, separated by two turning sections that bend the flow path of the exhaust gas, connected to the waste incinerator to recover heat from the exhaust gas A boiler having first and second radiation chambers having heat transfer surfaces, and a convection heat transfer chamber having a superheater that generates steam by heat exchange between the exhaust gas and the convection heat transfer surface of the heat transfer tube and further superheats. A boiler corrosion prevention device for preventing corrosion of the heat transfer tube due to dust adhering to the heat transfer tube of the convection heat transfer chamber,
A water injection device for removing adhering dust by injecting water onto the water cooling wall in the second radiation chamber;
An exhaust gas thermometer for measuring the exhaust gas temperature at the entrance of the convection heat transfer chamber;
A water injection control device for controlling the operation of the water injection device;
The water injection control device performs control to inject water from the water injection device when an exhaust gas temperature measurement value at a convection heat transfer chamber inlet by the exhaust gas thermometer is equal to or greater than a predetermined value. Corrosion prevention device.   The said water-injection control apparatus is controlled to inject water from the said water-injection apparatus, when the exhaust gas temperature measured value in the said convection heat transfer chamber inlet is 650 degreeC or more. Boiler corrosion prevention equipment. Radiation that generates steam by receiving radiant heat from the exhaust gas from the upstream side, separated by two turning sections that bend the flow path of the exhaust gas, connected to the waste incinerator to recover heat from the exhaust gas A boiler having first and second radiation chambers having heat transfer surfaces, and a convection heat transfer chamber having a superheater that generates steam by heat exchange between the exhaust gas and the convection heat transfer surface of the heat transfer tube and further superheats. A boiler corrosion prevention device for preventing corrosion of the heat transfer tube due to dust adhering to the heat transfer tube of the convection heat transfer chamber,
A water injection device for removing adhering dust by injecting water onto the water cooling wall in the second radiation chamber;
An exhaust gas thermometer for measuring the exhaust gas temperature at the most upstream superheater inlet of the convection heat transfer chamber;
A water injection control device for controlling the operation of the water injection device;
The water injection control device controls the water injection device to inject water when the exhaust gas temperature measurement value at the most upstream superheater inlet of the convection heat transfer chamber by the exhaust gas thermometer is a predetermined value or more. A boiler corrosion prevention device characterized by that.   The water injection control device controls to inject water from the water injection device when the exhaust gas temperature measurement value at the most upstream superheater inlet of the convection heat transfer chamber is 600 ° C. or more. The boiler corrosion prevention apparatus according to claim 7. Radiation that generates steam by receiving radiant heat from the exhaust gas from the upstream side, separated by two turning sections that bend the flow path of the exhaust gas, connected to the waste incinerator to recover heat from the exhaust gas A boiler having first and second radiation chambers having heat transfer surfaces, and a convection heat transfer chamber having a superheater that generates steam by heat exchange between the exhaust gas and the convection heat transfer surface of the heat transfer tube and further superheats. A boiler corrosion prevention method for preventing corrosion of the heat transfer tube due to dust adhering to the heat transfer tube of the convection heat transfer chamber,
Operation of a pressure wave generator that mixes fuel gas and oxidant gas under high pressure and burns them to generate pressure waves, and discharges pressure waves into the boiler from a pressure wave discharge nozzle disposed in the second radiation chamber Using a pressure wave generation control device that controls
The pressure wave generator is controlled so as to emit a pressure wave from the pressure wave discharge nozzle when a measured value of the exhaust gas temperature at the convection heat transfer chamber inlet measured by an exhaust gas thermometer is not less than a predetermined value. To prevent boiler corrosion.   Using the pressure wave generation control device, when the measured exhaust gas temperature at the convection heat transfer chamber inlet is 650 ° C. or higher, the pressure wave generation device is controlled to emit a pressure wave from the pressure wave discharge nozzle. The method for preventing corrosion of a boiler according to claim 9, wherein: Radiation that generates steam by receiving radiant heat from the exhaust gas from the upstream side, separated by two turning sections that bend the flow path of the exhaust gas, connected to the waste incinerator to recover heat from the exhaust gas A boiler having first and second radiation chambers having heat transfer surfaces, and a convection heat transfer chamber having a superheater that generates steam by heat exchange between the exhaust gas and the convection heat transfer surface of the heat transfer tube and further superheats. A boiler corrosion prevention method for preventing corrosion of the heat transfer tube due to dust adhering to the heat transfer tube of the convection heat transfer chamber,
Operation of a pressure wave generator that mixes fuel gas and oxidant gas under high pressure and burns them to generate pressure waves, and discharges pressure waves into the boiler from a pressure wave discharge nozzle disposed in the second radiation chamber Using a pressure wave generation control device that controls
When the exhaust gas temperature measurement value at the most upstream superheater inlet of the convection heat transfer chamber measured by the exhaust gas thermometer is equal to or greater than a predetermined value, the pressure wave generator is configured to emit a pressure wave from the pressure wave discharge nozzle. A method for preventing corrosion of a boiler, characterized by controlling.   When the exhaust gas temperature measurement value at the most upstream superheater inlet of the convection heat transfer chamber is 600 ° C. or higher using the pressure wave generation control device, the pressure wave is discharged from the pressure wave discharge nozzle. The method for preventing corrosion of a boiler according to claim 11, wherein the pressure wave generator is controlled. Radiation that generates steam by receiving radiant heat from the exhaust gas from the upstream side, separated by two turning sections that bend the flow path of the exhaust gas, connected to the waste incinerator to recover heat from the exhaust gas First and second radiation chambers having a heat transfer surface, a convection heat transfer chamber having a superheater that generates steam by heat exchange between the exhaust gas and the convection heat transfer surface of the heat transfer tube, and further superheats, and exhaust gas and heat transfer A boiler equipped with an economizer that heats the water supplied to the boiler by heat exchange with the convection heat transfer surface of the heat pipe, and the corrosion of the boiler that prevents corrosion of the heat transfer pipe due to dust adhering to the convection heat transfer chamber and the heat transfer pipe of the economizer A prevention method,
Using a water injection control device that controls the operation of the water injection device that injects water onto the water cooling wall in the second radiation chamber to remove adhering dust,
A method for preventing corrosion of a boiler, characterized in that water is injected when a measured value of exhaust gas temperature at a convection heat transfer chamber inlet measured by an exhaust gas thermometer is equal to or greater than a predetermined value.   The water injection control device is used to control to inject water from the water injection device when the measured exhaust gas temperature at the convection heat transfer chamber inlet is 650 ° C or higher. The method for preventing corrosion of a boiler as described in 1. Radiation that generates steam by receiving radiant heat from the exhaust gas from the upstream side, separated by two turning sections that bend the flow path of the exhaust gas, connected to the waste incinerator to recover heat from the exhaust gas First and second radiation chambers having a heat transfer surface, a convection heat transfer chamber having a superheater that generates steam by heat exchange between the exhaust gas and the convection heat transfer surface of the heat transfer tube, and further superheats, and exhaust gas and heat transfer A boiler equipped with an economizer that heats the water supplied to the boiler by heat exchange with the convection heat transfer surface of the heat pipe, and the corrosion of the boiler that prevents corrosion of the heat transfer pipe due to dust adhering to the convection heat transfer chamber and the heat transfer pipe of the economizer A prevention method,
Using a water injection control device that controls the operation of the water injection device that injects water onto the water cooling wall in the second radiation chamber to remove adhering dust,
A method for preventing corrosion of a boiler, characterized in that control is performed such that water is injected when a measured value of an exhaust gas temperature at an inlet of an uppermost stream side superheater of a convection heat transfer chamber measured by an exhaust gas thermometer is a predetermined value or more.   Using the water injection control device, when the exhaust gas temperature measurement value at the most upstream superheater inlet of the convection heat transfer chamber is 600 ° C. or higher, control is performed so that water is injected from the water injection device. The method for preventing corrosion of a boiler according to claim 15, characterized in that:

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