JP5984506B2 - Utilization method and system of waste heat in sulfuric acid production facility - Google Patents

Description

The present invention relates to a method and system for utilizing waste heat in a sulfuric acid production facility, and more specifically, sulfuric acid for producing sulfuric acid by using exhaust gas containing sulfurous acid gas (SO ₂ ) generated in a metal smelting process such as copper. A method and system for utilizing waste heat in a production facility, wherein steam generated by each waste heat boiler provided in a metal smelting facility and sulfuric acid production facility is introduced into a steam turbine to generate power and The present invention relates to a method and system for utilizing waste heat in a sulfuric acid production facility for heating pure water that is blown into a deaerator and sent to a waste heat boiler.

For example, in a copper smelting factory, sulfuric acid is produced using exhaust gas containing SO ₂ generated in a copper smelting process. The exhaust gas containing SO ₂ generated in the copper smelting process is introduced into the sulfuric acid manufacturing process after dust removal, washing and cooling. In the sulfuric acid production process, as shown in FIG. 1, residual moisture in the exhaust gas is removed by circulating concentrated sulfuric acid in the drying tower 101, heated through the heat exchangers 103 a and 103 b, and then introduced into the converter 110. The The converter 110 is filled with a catalyst (not shown), and SO ₂ is converted into SO ₃ , and a large amount of heat is generated at this time. This heat is used to raise the temperature of the exhaust gas on the low temperature side through the heat exchangers 103a and 103b as described above. Then, the mixed gas of SO ₃ and SO ₂ whose temperature has decreased is introduced into the first absorption tower 121. In the first absorption tower 121, SO ₃ in the gas is absorbed by concentrated sulfuric acid by direct contact with the concentrated concentrated sulfuric acid, and the sensible heat of the gas also moves to the concentrated sulfuric acid side. Then, the unabsorbed SO ₂ is heated and then introduced into the converter 110 again. The converted SO ₃ is absorbed by the concentrated concentrated sulfuric acid in the second absorption tower 122 and then discharged from the chimney 130.

  The heat recovered in the drying tower 101, the first absorption tower 121, and the second absorption tower 122 is cut out of the system by heat exchange between the concentrated concentrated sulfuric acid and seawater in the acid coolers 105, 125, and 126. .

The sulfuric acid production process, heat of formation of SO _3, absorption heat a large amount of occurred SO _3, but are outside of the system cut by heat exchange with the circulating acid and the sea water, the collecting excess heat generated by the following method I was going. That is, the high-temperature gas exiting the second layer of the converter 110 passes through the fourth heat exchanger (4HE) 103d and is introduced into the first absorption tower 101. The low temperature gas exiting the first absorption tower 101 passes through the fourth heat exchanger 103d again, exchanges heat with the outlet gas from the second layer, and enters the third layer. The heat exchanger 103e is installed in parallel with the fourth heat exchanger 103d, the air in the atmosphere is heated with surplus heat, and used for ore drying air, thereby reducing the amount of heavy oil used in the smelting process. I was planning.

However, the quality of copper contained in copper concentrate as a raw material for copper smelting tends to decrease year by year, while the quality of sulfur tends to increase. If the sulfur grade rises, the amount of SO ₂ contained in the exhaust gas discharged exceeding the sulfuric acid production capacity in the existing equipment will increase, so a new pre-converter 111 filled with a catalyst will be installed to convert the load increment. And the structure which collect | recovers the reaction surplus heat with the sulfuric-acid precomboiler (waste heat boiler) 140 was introduced. The high-pressure steam generated in the sulfuric acid pre-comboiler 140 is used for power generation by a saturated steam turbine, and the purchased power is reduced.

  Specifically, as shown in FIG. 2, steam generated from the waste heat boilers of the flash smelting boiler 141, the converter boiler 142, and the sulfuric acid precon boiler 140 is partially used for the factory, and the rest is the steam turbine 150. Used for power generation. The condensate pump 151 collects the steam drain 155 at various places in the pure water tank 160, and the shortage is supplemented by producing pure water with the pure water device 157. Pure water of 30 to 45 ° C. is sent from the pure water tank 160 to the deaerator 130 by a pure water supply pump 161 at 60 to 90 t / h, and steam is blown to remove dissolved oxygen to about 103 ° C. or more. Heated. And the pure water heated to about 105-110 degreeC is pressurized with the pump 131, and is sent to each waste-heat boiler 141,142,140.

  On the other hand, as a heat recovery method in a sulfuric acid production facility, for example, there is one disclosed in Patent Document 1. The heat recovery method in the sulfuric acid production facility of Patent Document 1 is a method aimed at heat recovery in a step of producing sulfuric acid by burning sulfur, that is, a production step mainly for sulfuric acid production.

  Moreover, as an acid cooler of acidic solutions, such as a sulfuric acid and phosphoric acid, there exists a thing shown in patent document 2, for example.

JP 2002-53311 A Japanese Utility Model Publication No. 62-131292

In the sulfuric acid production process using the exhaust gas including the sulfuric acid production process using the exhaust gas containing SO ₂ generated in the copper smelting process, the excess heat recovery as described above was performed, but the outside cut through the seawater still remains. There were many situations. Therefore, it was expected that further excess heat could be recovered.

  Moreover, there has been a problem that the amount of steam blown into the deaerator from each of the waste heat boilers 141, 142, 140 used for pure water heating is as large as 8 to 12 t / h. If this can be passed to the steam turbine 150, further increase in power generation efficiency can be expected.

  In this case, pure water is preheated by heat exchange with an acid cooler to obtain high-temperature supply water to the deaerator 130, thereby reducing the amount of steam blown into the deaerator 130 from each waste heat boiler 140, 141, 142. Although it is thought that it can be reduced, if a leak occurs in an acid cooler that exchanges heat between circulating acid and pure water, and pure water enters the circulating acid side, bumping due to the generation of dilution heat will occur. It may occur and the pipe may burst due to a sudden rise in pressure. In addition, since sulfuric acid, which is a circulating acid, increases in corrosion rate when the concentration is reduced, it is necessary to avoid mixing pure water on the circulating acid side.

Furthermore, in a factory that mainly uses metal smelting and produces sulfuric acid as a by-product using the exhaust gas, the amount of exhaust gas containing SO ₂ generated in the metal smelting process varies greatly depending on the operation status of the metal smelting. Therefore, there is a problem that it is extremely difficult to control the amount of SO ₂ .

The present invention has been made in view of the above problems, a flash smelting furnace boiler, converter boiler, flax surplus by introducing steam generated from the waste heat boiler, such as sulfuric Purekon boiler full steam turbine An object of the present invention is to provide a method for utilizing waste heat in a sulfuric acid production facility and a system therefor, in which it is possible to effectively use heat and there is no possibility of circulating pure water entering a circulating acid.

The present invention also provides waste heat in a sulfuric acid production facility that can efficiently recover waste heat even if the amount of exhaust gas containing SO ₂ generated in the metal smelting process varies greatly depending on the operation status of the metal smelting process. It is an object of the present invention to provide a usage method and a system thereof.

In order to achieve the above object, the invention described in claim 1 is a method for utilizing waste heat in a sulfuric acid production facility for producing sulfuric acid by using exhaust gas containing sulfurous acid gas (SO ₂ ) generated in a metal smelting process. Then, steam generated by each waste heat boiler provided in the metal smelting equipment and sulfuric acid production equipment is introduced into a steam turbine to generate electric power, and a part of the steam is blown into a deaerator to each waste heat. In the utilization method of waste heat in sulfuric acid production equipment that heats pure water sent to the boiler,
Pure water sent to the deaerator by a pure water supply pump is heat-exchanged with a high-temperature circulating acid in an acid cooler to preheat the pure water, and then sent to the deaerator to blow into the deaerator. By reducing the amount of steam and introducing the amount into the steam turbine, the power generation amount of the steam turbine is increased, and a pH meter is provided for measuring the pH of the pure water that has passed through the acid cooler. In addition, a bypass flow path is provided from the pure water tank directly to the deaerator without passing through the acid cooler, and when there is an abnormality in the pure water that has passed through the acid cooler by the pH meter, the pure water The flow of pure water from the tank to the acid cooler is cut off and sent to the deaerator through the bypass flow path.

In order to achieve the above object, the invention described in claim 2 is a method for utilizing waste heat in a sulfuric acid production facility for producing sulfuric acid by using exhaust gas containing sulfurous acid gas (SO ₂ ) generated in a metal smelting process. Then, steam generated by each waste heat boiler provided in the metal smelting equipment and sulfuric acid production equipment is introduced into a steam turbine to generate electric power, and a part of the steam is blown into a deaerator to each waste heat. In a method of using waste heat in a sulfuric acid production facility for heating pure water to be sent to a boiler, the pure water sent to the deaerator by a pure water supply pump is heat-exchanged with a high-temperature circulating acid in an acid cooler, thereby the pure water. When the amount of the steam blown into the deaerator is reduced by feeding the pre-heater to the deaerator and the amount of power generated by the steam turbine is increased by introducing the amount into the steam turbine. In, wherein the pressure of the circulating acid is introduced into the acid cooler was set to be relatively higher than the pressure of the pure water.

In order to achieve the above object, the invention according to claim 3 is the method of using waste heat in the sulfuric acid production facility according to claim 1 or 2 , wherein a pressure reducing valve is provided between the pure water supply pump and the acid cooler. And adjusting the pressure on the pure water side so that the pressure on the circulating acid side is higher than the pressure on the pure water side.

In order to achieve the above object, the invention according to claim 4 is a waste heat utilization system in a sulfuric acid production facility for producing sulfuric acid by using exhaust gas containing sulfurous acid gas (SO ₂ ) generated in a metal smelting process. Then, steam generated by each waste heat boiler provided in the metal smelting equipment and sulfuric acid production equipment is introduced into a steam turbine to generate electric power, and a part of the steam is blown into a deaerator to each waste heat. In a waste heat utilization system in a sulfuric acid production facility that heats pure water to be sent to a boiler, the pure water is preliminarily obtained by exchanging heat with high-temperature circulating acid pure water sent to the deaerator by a pure water supply pump. An acid cooler for heating is provided, and the amount of the steam blown into the deaerator is reduced by sending pure water heated by the acid cooler to the deaerator, and the amount is introduced into the steam turbine. With increasing power generation amount of the steam turbine by the pressure reducing valve between the pure water supply pump the acid cooler provided, so that the pressure of the circulating acid side becomes higher than the pressure of the pure water side The pressure adjustment on the pure water side is performed.

In order to achieve the above object, the invention described in claim 5 is a waste heat utilization system in a sulfuric acid production facility for producing sulfuric acid by using exhaust gas containing sulfurous acid gas (SO ₂ ) generated in a metal smelting process. Then, steam generated by each waste heat boiler provided in the metal smelting equipment and sulfuric acid production equipment is introduced into a steam turbine to generate electric power, and a part of the steam is blown into a deaerator to each waste heat. In a waste heat utilization system in a sulfuric acid production facility that heats pure water to be sent to a boiler, the pure water is preliminarily obtained by exchanging heat with high-temperature circulating acid pure water sent to the deaerator by a pure water supply pump. An acid cooler for heating, wherein the amount of the steam blown into the deaerator is reduced by sending pure water heated by the acid cooler to the deaerator, and the amount is introduced into the steam turbine. An acid cooler to increase the power generation amount of the steam turbine by Rukoto, and pH meter for measuring pH of the pure water that has passed through the acid cooler, the directly without passing through the acid cooler from the pure water tank A bypass flow path leading to the deaerator, a switching valve for switching the flow of pure water from the pure water tank to the acid cooler side or the bypass flow path side, and the deaerator from the pure water side outlet of the acid cooler An emergency shut-off valve that shuts off the flow path provided in the middle of the pipe leading to the pipe, and shuts off the shut-off valve when the pH meter detects that the pure water that has passed through the acid cooler is abnormal. The flow of pure water having an abnormality is cut off and the flow of pure water from the pure water tank is changed from the acid cooler side to the bypass flow path side by the switching valve. Therefore, it is provided with the control means to send directly to the said deaerator.

In order to achieve the above object, the invention according to claim 6 is the waste heat utilization system in the sulfuric acid production facility according to claim 4 or 5 , wherein the acid cooler is provided with an outlet from the pure water side to the emergency shut-off valve. The length of the piping is such that the abnormal pure water does not exceed the emergency shut-off valve until the control means detects the abnormality of the pure water and closes the emergency shut-off valve. And

  According to the method and system for utilizing waste heat in a sulfuric acid production facility according to the present invention, the amount of steam previously blown into the deaerator is reduced by increasing the temperature of pure water sent to the deaerator by circulating acid. Introducing into the steam turbine can increase the amount of power generated by the steam turbine. Thereby, the effective use of surplus heat can be aimed at.

  Further, according to the method and system for utilizing waste heat in the sulfuric acid production facility according to the present invention, even if a leak occurs in the acid cooler that performs heat exchange between the circulating acid and the pure water, the pure water is present on the circulating acid side. In addition to being able to prevent contamination, there is an effect that even if circulating acid is mixed into the pure water side, it is possible to prevent abnormal pure water from circulating.

Further, according to the method and system for utilizing waste heat in the sulfuric acid production facility according to the present invention, a pressure reducing valve is provided between the pure water supply pump and the acid cooler, and the pressure on the circulating acid side is higher than the pressure on the pure water side. Because the pressure on the pure water side is adjusted so that the pressure increases, the pressure on the pure water side can be adjusted even if the required amount of water supply changes due to fluctuations in the amount of SO ₂ due to changes in the operation status of copper smelting. There is an effect that it can be made lower than the circulating acid side and the safety of operation can be ensured.

It is a flowchart which shows a sulfuric acid manufacturing process. It is a flowchart which shows the conventional boiler water supply. It is a flowchart which shows one Embodiment of the boiler feed water in the utilization system of the waste heat which concerns on this invention. It is a flowchart which shows one Embodiment of the boiler feed water in the utilization method of the waste heat which concerns on this invention.

Hereinafter, the utilization method and system of waste heat in the sulfuric acid production facility according to the present invention will be described based on a preferred embodiment. FIG. 3 is an explanatory diagram showing a preferred embodiment of a waste heat utilization system in a sulfuric acid production facility according to the present invention.

  A waste heat utilization system (hereinafter simply referred to as “system”) 1 in the sulfuric acid production facility shown in FIG. 1 is provided between the pure water supply pump 161 and the deaerator 130 shown in FIG. That is, the system 1 generally includes a pure water supply pump 161 that sends out pure water stored in a pure water tank 160 (see FIG. 2), and pure water sent out by the pure water supply pump 161 is heated by circulating acid. The acid cooler 10 to be replaced, the pipe 21 for sending pure water from the pure water supply pump 161 to the acid cooler 10, the pipe 23 extending from the pure water side outlet of the acid cooler 10 to the deaerator 130, and the pure of the acid cooler 10 Bypass flow that is provided between the pipe 21 and the pipe 23 without passing through the acid cooler 10 and directly supplied to the deaerator 130 without passing through the acid cooler 10 and the pH meter 30 installed in the pipe 23 near the water-side outlet. A path 25, a first switching valve 41 provided in the pipe 21, a second switching valve 43 provided in the bypass flow path 25, an emergency shut-off valve 45 provided in the pipe 23, and a pH meter. When the pH value of pure water measured by the controller 30 is acquired and it is determined that the value is abnormal, the first switching valve 41, the second switching valve 43 and the emergency shutoff valve 45 are operated to And a control device 35 for switching the water flow path from the acid cooler 10 to the bypass flow path 25. In addition, when acid cooling is required, it cuts outside the system by exchanging heat with seawater by the acid coolers 105, 125, and 126 provided in the drying tower 101, the first absorption tower 121, and the second absorption tower 122.

  The first switching valve 41 normally flows pure water sent from the pure water supply pump 161 to the acid cooler 10 side, and is heated during heat exchange with the circulating acid due to a malfunction of the acid cooler 10. When the circulating acid is mixed into the pure water, the control device 35, which will be described later, shuts off the supply of pure water to the acid cooler 10 and exhibits a function of flowing the pure water to the bypass channel 25 side. . Therefore, it is arranged downstream of the branch point with the bypass channel 25.

  The second switching valve 43 is normally closed, and the pure water sent from the pure water supply pump 161 flows to the acid cooler 10 side. When circulating acid is mixed into the pure water heated at the time of replacement, it is opened by the control device 35 described later and the first switching valve 41 is closed to shut off the supply of pure water to the acid cooler 10. Thus, the valve exhibits a function of flowing pure water from the bypass flow path 25 side to the pipe 23 side. In the present embodiment, the first switching valve 41 and the second switching valve 43 are provided, but one switching valve that switches the flow path to the branch point between the pipe 21 and the bypass flow path 25 is provided. It can also be set as the structure which switches a flow path by providing.

  The emergency shut-off valve 45 is normally opened, and sends pure water heated by heat exchange with the circulating acid in the acid cooler 10 to the deaerator 130. When the circulating acid is mixed in the pure water heated during the heat exchange, the function is shut off by the control device 35, which will be described later, so that the abnormal pure water does not reach the deaerator 130. It is a valve that demonstrates it. The deaerator 130 is provided with a level meter (not shown), and the amount of water supply is adjusted so as to ensure an appropriate amount of water.

  The pH meter 30 is installed in the pipe 23 near the outlet on the pure water side of the acid cooler 10 and measures the pH of pure water heated by exchanging heat with the circulating acid. The measurement results are sequentially sent to the control device 35.

  The control device 35 monitors the measured value sent from the pH meter 30, and determines that it is abnormal when it deviates from the preset set value, and the first switching valve 41, the second switching valve 43, and the like. The emergency shutoff valve 45 is operated to switch the pure water flow path from the acid cooler 10 to the bypass flow path 25. For example, when the pH of pure water falls below 7.0 and is inclined to the acidic side, it is determined that there is contact with the circulating acid in the acid cooler 10 and is abnormal. This prevents pure water contaminated with acid from flowing into the deaerator 130. The control device 35 includes a storage device that stores a program of a predetermined procedure, a CPU that executes the program, an input device that inputs necessary information, and a display device such as a display that acquires necessary information (both not shown). And a general electronic processing apparatus (computer) provided with the above, and since these are well known, the description thereof is omitted.

  The acid cooler 10 heats pure water by exchanging heat between the hot circulating acid and pure water. The acid cooler 10 of this embodiment may be any one that can exchange heat between the circulating acid and pure water. For example, a shell-and-tube heat exchanger is used, but typically, an anodic anticorrosion acid cooler is used to improve corrosion resistance. Is used. The anodic anticorrosion acid cooler is intended to prevent corrosion of the portion in contact with the acid by raising the potential on the metal side to a passive region by an external power source. In addition, since seawater has been used as the cooling water so far, a base metal that is lower than the material of the cooler is joined to the surface of the cooling water side path in the acid cooler 10 in order to prevent corrosion of the portion that contacts the seawater. The corrosion of the acid cooler tube has been performed by preferentially corroding the acid cooler tube (not shown). Examples of base metals include zinc and iron. When the cooling water is pure water as in the present invention, there are few corrosion problems. On the contrary, there is a concern about deterioration of the quality of pure water due to dissolution of the anticorrosive metal, so the anticorrosive metal was removed. Furthermore, in order to reliably suppress the elution of the metal due to the corrosion of the acid cooler tube, it is possible to use SUS or ZeCor (registered trademark of MECS, Inc.) that does not have such a fear. In addition, even if a leak occurs by preventing the circulating acid from being introduced into the acid cooler 10 in advance by making the pressure of the circulating acid relatively higher than the pressure of the pure water, the pure water is prevented from entering the circulating acid side. can do.

  Further, the length from the outlet on the pure water side of the acid cooler 10 to the emergency shut-off valve 45 attached to the pipe 23 is the length between the time when the controller 35 detects the abnormality of pure water and closes the emergency shut-off valve 45. It is possible to prevent the pure water contaminated with the circulating acid from being sent to the deaerator 130 by ensuring the length that the abnormal pure water does not exceed the emergency shutoff valve 45. The length from the outlet on the pure water side of the acid cooler 10 to the emergency shutoff valve 45 attached to the pipe 23 is appropriately determined depending on the diameter of the pipe 23, water pressure, etc., and can be, for example, 200 to 500 m. . Thereby, it is possible to prevent the pure water from being mixed into the circulating acid side, and to prevent the abnormal pure water from circulating even if the circulating acid is mixed into the pure water side. .

  Further, a pressure reducing valve 47 is provided in the middle of the pipe 21 arranged between the pure water supply pump 161 and the pure water inlet side of the acid cooler 10. The pressure reducing valve 47 adjusts the pure water pressure of the pure water supply pump 161 to be relatively lower than the pressure on the circulating acid side. That is, when the operation status in copper smelting changes, the amount of water required in each of the waste heat boilers such as the flash smelting boiler 141, the converter boiler 142, and the sulfuric acid pre-combustion boiler 140 varies. When the amount of water required in each waste heat boiler varies, the amount of water supplied to the deaerator 130 also varies. And since the rotational speed of the pure water supply pump 161 is constant, when the amount of water supplied to the deaerator 130 decreases, the piping from the outlet of the pure water supply pump 161 to the flow rate control valve 49 via the acid cooler 10 is reduced. The pressure will increase.

  Here, the reason why the amount of water supplied to the deaerator 130 is reduced will be described. The necessary water amounts of the waste heat boilers 140, 141, and 142 are sent from the deaerator 130. On the other hand, water is supplied to the deaerator 130 through the acid cooler 10. The deaerator 130 is provided with a level meter (not shown), and a flow rate adjusting valve 49 is arranged on the pipe 23 leading from the acid cooler 10 to the deaerator 130 before the entrance of the deaerator 130. The flow rate of pure water received in the deaerator 130 is adjusted according to the level of pure water stored in the deaerator 130. For this reason, if the amount of pure water required in each waste heat boiler 140, 141, 142 decreases, the amount of water sent from the deaerator 130 decreases, and the amount of pure water in the deaerator 130 increases. Since the water level is increased, it is necessary to reduce the amount of pure water supplied to the deaerator 130 by reducing the opening of the flow rate adjustment valve 49.

In such a situation, since the pure water pressure from the outlet of the pure water supply pump 161 to the flow rate adjustment valve 49 via the acid cooler 10 increases, the supply of pure water is performed by the pressure reducing valve 47 provided on the pure water supply pump 161 side. By reducing the pressure, the pressure of the circulating acid in the acid cooler 10 is made relatively higher than the pressure of the pure water, thereby maintaining the pressure balance between the pure water and the circulating acid. Thus, the safety of even Hen' water supply amount required amount of SO ₂ is changed can be made lower than the pressure of the circulating acid side of the pure water side operating by such operations status of the copper smelting changes It can be secured.

  Next, a method for utilizing waste heat in the sulfuric acid production facility according to the present invention will be described together with the operation of the system 1. FIG. 4 is a flowchart of an embodiment of a method for utilizing waste heat in a sulfuric acid production facility according to the present invention.

[Normal case]
Pure water stored in the pure water tank 160 is sent to the acid cooler 10 via the pipe 21 by the pure water supply pump 161. The pure water is heated by the acid cooler 10 by heat exchange with the hot circulating acid and sent to the outlet side. In the vicinity of the outlet on the pure water side of the acid cooler 10, the pH of the pure water heated by the pH meter 30 is measured, and the result is sent to the control device 35 (step S1). If the pH value is within a predetermined range, for example, pH 7.0 or more (step S2), the control device 35 opens the first switching valve 41, closes the second switching valve 43, and opens the emergency shutoff valve 45. As described above, pure water is supplied to the deaerator 130 through the pipe 23 (step S3).

[If there is an abnormality]
When there is an abnormality in the measurement result of the pH meter 30, for example, when the pH is lower than 7.0, the control device 35 closes the first switching valve 41, opens the second switching valve 43, and makes an emergency. With the shut-off valve 45 closed (step S4), pure water is sent from the pipe 21 to the pipe 23 via the bypass flow path 25 without passing through the acid cooler 10 and supplied to the deaerator 130 (step S5). Thereby, contamination by the circulating acid of pure water is prevented. Further, the length from the outlet on the pure water side of the acid cooler 10 to the emergency shut-off valve 45 attached to the pipe 23 is the length between the time when the controller 35 detects the abnormality of pure water and closes the emergency shut-off valve 45. Since the length of the abnormal pure water that does not exceed the emergency shutoff valve 45 is ensured, the pure water contaminated with acid is prevented from being sent to the deaerator 130 in advance. In the example of the above-described embodiment shown in FIG. 4, the abnormal state of pure water is set to “below pH 7”. However, depending on the material of the acid cooler tube, it does not corrode even if the pure water becomes slightly acidic. In that case, the abnormal state may be set, for example, as “when pH is below 5”.

  In addition, when the operation status in the copper smelting process fluctuates, the amount of water required by each waste heat boiler 140, 141, 142 decreases and the amount of water supplied from the deaerator 130 decreases, the pure water in the deaerator 130 Therefore, the opening amount of the flow rate adjustment valve 49 is reduced to reduce the amount of pure water supplied to the deaerator 130 and the pure water is supplied by the pressure reducing valve 47 provided on the pure water supply pump 161 side. By reducing the pressure, the pressure of the circulating acid in the acid cooler 10 is made relatively higher than the pressure of pure water. Thereby, the pressure balance of pure water and a circulating acid can be maintained, and the safety | security of operation can be ensured.

(1) Increase in sulfuric acid waste heat recovery amount As a result of boiler water preheating by heat exchange with circulating acid, pure water 74t / h is preheated from 40 ° C to 75 ° C, and 10.8GJ / h waste heat is recovered. I was able to.
As a result, 3.3% of the waste heat in the sulfuric acid production process could be recovered, and the unrecovered waste heat was changed from 86.8% to 83.5%.
(2) Increase in Steam Turbine Power Generation Since pure water is preheated with circulating acid in the acid cooler 10, the feed water heating steam used in the deaerator 130 can be reduced, and the power generation amount of the steam turbine is 7.7 per year. % Could be increased. In addition, the amount of CO ₂ emissions could be reduced by reducing the amount of purchased power.

  As described above, the preferred embodiment of the present invention has been described in detail. However, the present invention is not limited to the specific embodiment, and within the scope of the gist of the present invention described in the claims, Needless to say, various modifications and changes are possible.

DESCRIPTION OF SYMBOLS 1 Waste heat utilization system 10 Acid cooler 21 Pipe 23 Pipe 25 Bypass flow path 30 pH meter 35 Control apparatus 41 1st switching valve 43 2nd switching valve 45 Emergency shutoff valve 47 Pressure reducing valve 49 Flow regulating valve 130 Deaerator 161 Pure water supply pump

Claims (6)

A method of using waste heat in a sulfuric acid production facility for producing sulfuric acid by using exhaust gas containing sulfurous acid gas (SO ₂ ) generated in a metal smelting process, each of which is provided in a metal smelting facility and a sulfuric acid production facility Waste heat in a sulfuric acid production facility that introduces steam generated by a waste heat boiler into a steam turbine to generate electricity and blows a part of the steam into a deaerator to heat pure water sent to each waste heat boiler. In the usage of
Pure water sent to the deaerator by a pure water supply pump is heat-exchanged with a high-temperature circulating acid in an acid cooler to preheat the pure water, and then sent to the deaerator to blow into the deaerator. By reducing the amount of steam and introducing the amount into the steam turbine, the power generation amount of the steam turbine is increased , and a pH meter is provided for measuring the pH of the pure water that has passed through the acid cooler. In addition, a bypass flow path is provided from the pure water tank directly to the deaerator without passing through the acid cooler, and when there is an abnormality in the pure water that has passed through the acid cooler by the pH meter, the pure water A method for utilizing waste heat in a sulfuric acid production facility, wherein a flow of pure water from a tank to the acid cooler is cut off and sent to the deaerator through the bypass flow path . A method of using waste heat in a sulfuric acid production facility for producing sulfuric acid by using exhaust gas containing sulfurous acid gas (SO ₂ ) generated in a metal smelting process, each of which is provided in a metal smelting facility and a sulfuric acid production facility Waste heat in a sulfuric acid production facility that introduces steam generated by a waste heat boiler into a steam turbine to generate electricity and blows a part of the steam into a deaerator to heat pure water sent to each waste heat boiler. In the usage of
Pure water sent to the deaerator by a pure water supply pump is heat-exchanged with a high-temperature circulating acid in an acid cooler to preheat the pure water, and then sent to the deaerator to blow into the deaerator. By reducing the amount of steam and introducing the amount into the steam turbine, the power generation amount of the steam turbine is increased, and the pressure of the circulating acid introduced into the acid cooler is relative to the pressure of the pure water. A method for using waste heat in a sulfuric acid production facility, characterized in that the height of the sulfuric acid is increased . In the utilization method of the waste heat in the sulfuric acid manufacturing facility of Claim 1 or 2 ,
A pressure reducing valve is provided between the pure water supply pump and the acid cooler, and the pressure on the pure water side is adjusted so that the pressure on the circulating acid side is higher than the pressure on the pure water side. Of waste heat in sulfuric acid production facilities. A waste heat utilization system in a sulfuric acid production facility that produces sulfuric acid by using exhaust gas containing sulfurous acid gas (SO ₂ ) generated in a metal smelting process, each of which is provided in a metal smelting facility and a sulfuric acid production facility Waste heat in a sulfuric acid production facility that introduces steam generated by a waste heat boiler into a steam turbine to generate electricity and blows a part of the steam into a deaerator to heat pure water sent to each waste heat boiler. In the usage system of
An acid cooler that preheats the pure water by heat-exchanging the pure water sent to the deaerator by a pure water supply pump with a high-temperature circulating acid is provided, and the deionizer heats the pure water heated by the acid cooler. The amount of the steam blown into the deaerator is reduced by sending to the deaerator, and the amount of power generated by the steam turbine is increased by introducing the amount into the steam turbine, and between the pure water supply pump and the acid cooler A system for using waste heat in a sulfuric acid production facility, characterized in that a pressure reducing valve is provided between the two, and the pressure on the pure water side is adjusted so that the pressure on the circulating acid side is higher than the pressure on the pure water side. A waste heat utilization system in a sulfuric acid production facility that produces sulfuric acid by using exhaust gas containing sulfurous acid gas (SO ₂ ) generated in a metal smelting process, each of which is provided in a metal smelting facility and a sulfuric acid production facility Waste heat in a sulfuric acid production facility that introduces steam generated by a waste heat boiler into a steam turbine to generate electricity and blows a part of the steam into a deaerator to heat pure water sent to each waste heat boiler. In the usage system of
An acid cooler that preheats the pure water by exchanging the pure water sent to the deaerator with a pure water supply pump with a high-temperature circulating acid, and the pure water heated by the acid cooler is degassed. An acid cooler that reduces the amount of the steam blown into the deaerator by sending it to a steam generator, and increases the power generation amount of the steam turbine by introducing the amount into the steam turbine;
A pH meter for measuring the pH of the pure water that has passed through the acid cooler;
A bypass flow path from the pure water tank directly to the deaerator without passing through the acid cooler;
A switching valve for switching the flow of pure water from the pure water tank to the acid cooler side or the bypass flow path side;
An emergency shutoff valve for shutting off a flow path provided in the middle of the pipe from the outlet on the pure water side of the acid cooler to the deaerator;
When the pH meter detects that there is an abnormality in the pure water that has passed through the acid cooler, the shut-off valve is shut off to shut off the flow of abnormal pure water, and the pure water is switched by the switching valve. Control means for sending the pure water flow from the water tank directly to the deaerator by changing from the acid cooler side to the bypass flow path side;
A system for utilizing waste heat in a sulfuric acid production facility. In the waste heat utilization system in the sulfuric acid production facility according to claim 4 or 5 ,
The length of the pipe from the outlet on the pure water side of the acid cooler to the emergency shutoff valve is abnormal between the time when the control means detects the abnormality of the pure water and closes the emergency shutoff valve. A system for utilizing waste heat in a sulfuric acid production facility, characterized in that pure water has a length that does not exceed the emergency shutoff valve.

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