WO2023021860A1

WO2023021860A1 - Boiler

Info

Publication number: WO2023021860A1
Application number: PCT/JP2022/026241
Authority: WO
Inventors: 裕介岡本; 務佐々木
Original assignee: 三浦工業株式会社
Priority date: 2021-08-20
Filing date: 2022-06-30
Publication date: 2023-02-23

Abstract

A boiler (1) according to one embodiment of the present invention is provided with: a burner (11) for combusting a non-carbon fuel containing hydrogen and not containing carbon; a can body (12) for generating steam by the heat of combustion gas generated by the burner (11); a latent heat recovery device (21) for recovering latent heat into supplementary water supplied to the can body (12), from combustion gas that has traveled through the can body (12); a condensed water tank (41) for storing condensed water obtained by moisture in combustion gas condensing in the latent heat recovery device (21); and, a condensed water supply line (42) for supplying condensed water stored in the condensed water tank (41) to the can body.

Description

boiler

The present invention relates to boilers.
This application claims priority based on Japanese Patent Application No. 2021-134679 filed in Japan on August 20, 2021, the contents of which are incorporated herein.

In various factories, etc., a small package boiler is often installed that generates steam by heating the can body filled with water by the combustion gas of the burner. As a technique for improving the energy efficiency of a boiler, it is known to provide an economizer that heats make-up water with combustion gas discharged from the boiler (see, for example, Patent Document 1). In such an economizer, latent heat recovery of combustion gas may be performed in order to improve boiler efficiency.

In addition, in boilers, if steam continues to be generated, the concentration of impurities in the boiler water (water inside the boiler) will increase, causing scale adhesion and carryover. Therefore, a part of boiler water with an increased concentration of impurities is blown out of the system, and new make-up water is supplied. In order to suppress heat loss due to high-temperature blow water, control such as setting an appropriate blow interval based on the amount of combustion and the concentration of impurities in the make-up water is performed.

JP-A-9-250818

In recent years, as interest in the global environment has increased, even small boilers are required to use resources and energy more efficiently. Therefore, an object of the present invention is to provide a boiler with excellent energy efficiency.

A boiler according to an aspect of the present invention includes a burner for burning a non-carbon fuel containing hydrogen and not containing carbon (hereinafter, the fuel containing hydrogen and not containing carbon is referred to as a non-carbon fuel), and combustion generated by the burner A can body that generates steam by the heat of gas, a latent heat recovery device that recovers latent heat from the combustion gas that has passed through the can body to make-up water that is supplied to the can body, and moisture in the combustion gas in the latent heat recovery device. and a condensed water supply line for supplying the condensed water stored in the condensed water tank to the can body.

In the boiler described above, the latent heat recovery device is a heat exchanger that exchanges heat between makeup water supplied to the boiler and combustion gas, and the boiler is independent of the condensed water supply line. and an independent makeup water supply line for supplying makeup water to the can body through the latent heat recovery device.

The boiler described above further includes a make-up water premixing line that supplies make-up water to the condensed water tank. The latent heat recovery device may be a heat exchanger that exchanges heat between the mixed water of condensed water and make-up water and the combustion gas.

The above-described boiler further includes a makeup water primary supply line that supplies makeup water to the latent heat recovery device, the latent heat recovery device is a sprinkler that sprinkles makeup water in the flow path of the combustion gas, and the condensed water The tank may collect make-up water sprayed together with the condensed water, and the condensed water supply line may supply mixed water of the condensed water and make-up water to the can body.

The above-described boiler includes a make-up water premixing line that supplies make-up water to the condensed water tank, a mixed water supply line that supplies mixed water of condensed water and make-up water from the condensed water tank to the latent heat recovery device, and the latent heat recovery device may be a sprinkler that sprinkles mixed water of condensed water and make-up water in the flow path of the combustion gas.

The above-described boiler may further include a blow control section that adjusts the blow rate from the can body based on the respective amounts of condensed water and make-up water supplied to the can body.

In the boiler described above, the blow control unit may calculate the supply amount of condensed water based on the supply amount of non-carbon fuel.

The boiler described above may include a filtering device in the condensed water supply line.

The above-described boiler further includes a chemical feeding device for chemically feeding makeup water, and a chemical feeding control section for controlling the chemical feeding amount of the chemical feeding device, and the chemical feeding control section is supplied to the can body. The chemical feeding amount may be adjusted based on the supply amount of condensed water.

In the boiler described above, the chemical dosing control unit may calculate the supply amount of condensed water based on the supply amount of non-carbon fuel.

According to the present invention, a boiler with excellent energy efficiency can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the structure of the boiler which concerns on 1st Embodiment of this invention. 4 is a graph showing the relationship between the combustion gas exhaust temperature and the amount of condensed water collected. 4 is a graph showing the relationship between combustion gas exhaust temperature and boiler efficiency when hydrogen fuel is used. 4 is a graph showing the relationship between combustion gas discharge temperature and boiler efficiency when city gas is used. It is a schematic diagram which shows the structure of the boiler which concerns on 2nd Embodiment of this invention. FIG. 5 is a schematic diagram showing the configuration of a boiler according to a third embodiment of the present invention; It is a schematic diagram which shows the structure of the boiler which concerns on 4th Embodiment of this invention.

Hereinafter, each embodiment of the present invention will be described with reference to the drawings. In addition, in the embodiments described later, the same reference numerals may be assigned to the same components as in the previously described embodiments, and overlapping descriptions may be omitted.

<First Embodiment>
FIG. 1 is a schematic diagram showing the configuration of a boiler 1 according to the first embodiment of the present invention. The boiler 1 can be a relatively small, space-saving and highly efficient package boiler that can be provided assembled, with all the components shown arranged on a common base. Typically, the boiler 1 can be a small once-through boiler and a small once-through boiler.

The boiler 1 includes a boiler body 10 having a burner 11 and a can body 12, an exhaust stack 20 attached to the boiler body 10 and having a latent heat recovery device 21 disposed therein, and make-up water supplied to the can body 12. A make-up water tank 31 to be stored, a make-up water independent supply line 32 for supplying the make-up water from the make-up water tank 31 to the can body 12 through the latent heat recovery device 21, and condensed water in which moisture in the combustion gas is condensed in the latent heat recovery device 21. condensed water tank 41 for storing condensed water tank 41, condensed water supply line 42 for supplying condensed water from condensed water tank 41 to boiler body 12, chemical injection device 51 for injecting chemical into make-up water (chemical injection), and other configurations a controller 60 for controlling the operation of the elements. In this specification, "make-up water" means water supplied from outside the system, and water supplied to the boiler body 12 regardless of the source is referred to as "boiler feed water". .

The burner 11 generates high-temperature combustion gas by burning a mixed gas of non-carbon fuel containing hydrogen and not containing carbon and combustion air. Since the burner 11 burns the non-carbon fuel, the combustion gas practically does not contain carbon dioxide and unburned carbon (soot) derived from the hydrocarbon fuel. easier. Non-carbon fuels include hydrogen and ammonia and mixtures thereof. It should be noted that non-carbon fuels are allowed to contain trace amounts of hydrocarbons at impurity levels.

As the combustion air used by the burner 11, it is preferable to use clean air with a carbon dioxide concentration of 1000 ppm or less while minimizing the contamination of hydrocarbon fuel combustion gas and the like. This makes it possible to suppress carbonic acid substances in the condensed water.

Also, the burner 11 is preferably designed and combustion controlled so that the concentration of nitrogen oxides in the combustion gas is 50 ppm (at 0% O2) or less. As a result, it is possible to prevent the pH of the condensed water from lowering due to the dissolution of nitrogen oxides.

The can body 12 recovers heat from the combustion gas generated by the burner 11 and generates steam. The boiler body 12 extends vertically and includes a plurality of water tubes 13 arranged to surround the flame formed by the burner 11, and a lower header 14 connected to the lower ends of the plurality of water tubes 13 and supplying boiler water to each of the water tubes 13. and an upper header 15 connected to the upper ends of the plurality of water tubes 13 to collect water vapor generated in the water tubes 13 . Further, the can body 12 is provided with a blow valve 16 for discharging boil water.

The base side of the exhaust pipe 20 is connected to the can body 12 and exhausts the combustion gas generated in the can body 12 to the outside via the latent heat recovery device 21 . The exhaust pipe 20 has a first upward exhaust passage portion, a downward exhaust passage portion, and a second upward exhaust passage portion, and the latent heat recovery device 21 is preferably provided in the downward exhaust passage portion. By configuring in this way, it is possible to suppress the droplets of condensed water generated by condensation of moisture in the combustion gas in the latent heat recovery device 21 from being accompanied with the combustion gas and discharged.

The exhaust stack 20 has, below the latent heat recovery device 21, a recovery section 22 that recovers condensed water generated from water vapor in the combustion gas. The recovery unit 22 may be controlled in water level or provided with a trap so as not to become a path for the combustion gas to leak.

The latent heat recovery device 21 recovers latent heat from the combustion gas generated in the can body 12 to make-up water supplied to the can body 12 . In this embodiment, the latent heat recovery device 21 is a heat exchanger that exchanges heat between the make-up water supplied to the boiler 12 and the combustion gas. The latent heat recovery device 21 recovers the sensible heat of the combustion gas and also recovers the latent heat by condensing water vapor contained in the combustion gas. Therefore, the latent heat recovery device 21 produces condensed water by condensing water in the combustion gas. Note that the latent heat recovery device 21 is preferably made of a highly corrosion-resistant material so that the components of the constituent material do not elute into the condensed water.

The temperature (exhaust temperature) of the combustion gas at the outlet of the latent heat recovery device 21 is preferably 40°C or higher and 65°C or lower, more preferably 50°C or higher and 60°C or lower. By reducing the discharge temperature of the combustion gas to within this range, it is not necessary to increase the size or improve the performance of the latent heat recovery device 21. Therefore, the amount of condensed water recovered from the combustion gas can be reduced while suppressing costs. It can be secured and used stably as part of the boiler feed water. Further, by continuously recovering a predetermined amount or more of condensed water, it is difficult for the concentration of impurities to increase due to evaporation or the like until the condensed water is supplied to the boiler body 12, and problems related to water quality can be suppressed. Furthermore, by securing the amount of condensed water, it can also be used in combination with other means for the purpose of saving energy, such as preheating make-up water using various types of exhaust heat, mixing drain water in steam lines with make-up water, etc. Stable heat recovery by condensed water is possible by suppressing the influence of them.

In the combustion of non-carbon fuels, the primary combustion products are water (water for hydrogen fuels, water and nitrogen (3:1 gas volume ratio) for ammonia fuels), compared to combustion of hydrocarbon fuels. A remarkably large amount of condensed water is generated as the temperature of the combustion gas decreases. FIG. 2 shows the relationship between the exhaust temperature of the combustion gas from the latent heat recovery device 21 and the ratio of the amount of condensed water recovered to the amount of water supplied to the boiler when hydrogen gas and city gas (13A) are used as fuel. show. In addition, FIG. 2 was obtained by calculation with O2 = 5% (air ratio 1.32), and was calculated with a dew point of 71 ° C for hydrogen and 54 ° C for city gas. be. When the temperature of the combustion gas is sufficiently lowered by the latent heat recovery device 21, for example, hydrogen gas is used as the non-carbon fuel, the temperature of the combustion gas is lowered to 60 ° C. in the latent heat recovery device 21, and condensed water is added to the combustion gas. If not discharged (carried over), 47% of the water produced by combustion can be recovered as condensed water, which corresponds to the amount of evaporated water in the boiler body 12, that is, 10% of the boiler feed water amount. Also, when the combustion gas temperature is lowered to 50° C., the condensed water becomes 70% of the combustion water, which corresponds to 14% of the boiler water supply. On the other hand, when city gas (13A) is used as fuel, if the combustion gas temperature is lowered to 60°C, there is no condensed water in calculation, and even if the combustion gas temperature is lowered to 50°C, However, the condensed water is only 20% of the combustion water and only 2% of the boiler feed water. Thus, in the combustion of hydrogen gas, the water dew point is relatively high because the amount of water in the combustion gas is large. Compared to city gas, the temperature entering the latent heat recovery zone is higher, and the latent heat recovery greatly improves boiler efficiency. Therefore, a sufficient amount of condensed water can be recovered under realistic operating conditions of the latent heat recovery device 21 .

The make-up water tank 31 stores make-up water, and the make-up water is supplied from the make-up water original supply line 33 by a well-known means such as a ball tap so as to keep the liquid level of the make-up water above a certain level.

The make-up water independent supply line 32 is provided independently from the condensed water supply line 42 and has a make-up water pump 34 for sending out make-up water, and supplies make-up water to the lower header 14 via the latent heat recovery device 21. . Since high-temperature condensed water generated in the latent heat recovery device 21 is not mixed with the make-up water independent supply line 32, the water temperature of the make-up water introduced into the latent heat recovery device 21 does not rise, and the heat exchange efficiency does not decrease.

The condensed water tank 41 receives the condensed water generated in the latent heat recovery device 21 and recovered in the recovery unit 22 by at least one of a drop, an ejector, and a pump. By storing the condensed water in the condensed water tank 41 , it becomes possible to stably supply the condensed water to the lower header 14 of the boiler body 12 through the condensed water supply line 42 . In addition, dissolution of oxygen from the water surface of the condensed water tank 41 is prevented, and the condensed water generated in a high-temperature, low-oxygen state can be supplied to the lower header 14 while maintaining a low oxygen concentration. The recovery unit 22 and the condensed water tank 41 may be configured integrally.

The condensed water supply line 42 supplies condensed water to the lower header 14 from the condensed water tank 41 that stores condensed water generated in the latent heat recovery device 21 and recovered in the recovery unit 22 . Since high-temperature condensed water is supplied to the lower header 14 through the shortest route without being mixed with make-up water, it is possible to suppress a decrease in the temperature of the condensed water, and to effectively utilize the heat capacity of the condensed water to increase boiler efficiency. can be done. On the other hand, the make-up water is not mixed with the condensed water on the upstream side of the latent heat recovery device 21, and the heat exchange capacity does not decrease due to the increase in water temperature.

In addition, since the condensed water generated in the latent heat recovery device 21 contains almost no corrosive components such as scale components, chloride ions, and sulfate ions (mainly derived from combustion air and may contain only trace amounts), condensation By supplying condensed water through the water supply line 42, the blow rate can be reduced, and heat loss and chemical loss associated with blowing can be reduced.

The condensed water supply line 42 includes a filtering device 43 for removing foreign substances in the condensed water, a condensed water pump 44 for sending out the condensed water, and a condensed water flow meter 45 for measuring the flow rate of the condensed water supplied to the boiler body 12. and are provided. The filtering device 43 removes, for example, inorganic particles contained in the combustion air, oxides of the material of the can body, etc., as well as substances dropped from the exhaust pipe 20 and the latent heat recovery device 21, when the condensed water is mixed with such foreign substances. is prevented from entering the can body 12. The filtering device 43 is preferably made of metal, and may be provided with a filtering part such as a corrosion-resistant metal mesh.

The condensed water pump 44 (and the filtering device 43) is provided in close proximity to the can body 12 and the exhaust stack 20, or close to the side of the exhaust stack 20 opposite to the can body 12. If the condensed water tank 41 is provided close to the boiler 12 or the exhaust stack 20 , the condensed water pump 44 may be provided close to the condensed water tank 41 . By arranging the condensed water pump 44 and the boiler body 12 and/or the condensed water pump 44 and the condensed water tank in close proximity, heat loss from the condensed water can be suppressed. Moreover, in space-saving small once-through boilers and small-scale once-through boilers, there is an advantage that the condensed water pump 44 and the like can be installed compactly.

The chemical injection device 51 injects chemicals such as pH adjusters, scale inhibitors, and corrosion inhibitors into the supplementary water. In this embodiment, the chemical injection device 51 injects the chemical into the supplementary water tank 31, but may be arranged to inject the chemical into the supplementary water independent supply line 32 or the like, for example.

The control device 60 includes a combustion control unit 61 that controls the amount of non-carbon fuel and combustion air supplied to the burner 11 , a makeup water control unit 62 that controls the makeup water pump 34 , and a condensate water controller that controls the condensate pump 44 . It has a water control unit 63 , a chemical injection control unit 64 that controls the chemical injection device 51 , and a blow control unit 65 that controls the blow valve 16 .

The combustion control unit 61 controls the amount of combustion, that is, the amount of non-carbon fuel and combustion air supplied, so that the steam pressure of the upper header 15 is kept within a predetermined range, and fuel is supplied according to the amount of combustion air. will be　

The make-up water control unit 62 adjusts the supply of make-up water (amount and timing) so that the water level in the water pipe 13 is kept within a predetermined range according to the combustion state.

The condensed water control unit 63 maintains the water level of the condensed water tank 41 within a predetermined range, and cooperates with the supplementary water control unit 62 so that the supply (amount and timing) of the condensed water to the can body is appropriate. Control the condensate pump 44 . When the total amount of condensed water generated in the latent heat recovery device 21 is used as boiler feed water, the boiler efficiency can be further increased by 1% compared to the case where only latent heat exchange is performed, according to calculations assuming that there is no condensed water loss. . FIG. 3 shows the relationship between the combustion gas discharge temperature and the boiler efficiency (relative value) when hydrogen gas is used as the fuel. A case where only heat is recovered and latent heat is not recovered is illustrated separately. FIG. 4 also shows the boiler efficiency when city gas (13A) is used as fuel. As shown in the figure, when hydrogen gas is used as the fuel, the latent heat recovery and condensed water recovery are highly effective in improving boiler efficiency. 3 and 4, the conditions such as the air ratio are the same as in FIG. 2, and the boiler efficiency is described based on the lower calorific value. When latent heat recovery is performed, the latent heat of the condensed water is the efficiency improvement compared to when the latent heat recovery is not performed, and when the condensed water is recovered, the sensible heat of the recovered condensed water is the further efficiency improvement. It's becoming

The chemical injection control unit 64 adjusts the amount of chemical injection by the chemical injection device 51 based on the amount of condensed water supplied to the can body 12 , that is, the measured value of the condensed water flow meter 45 . For example, the chemical dosing control unit 52 has a proportionality constant set based on the assumed quality of make-up water, determines the amount of chemical dosing in proportion to the amount of make-up water required from the boiler main body 10, and uses the condensed water flow meter It may be configured to adjust the dosing volume proportionality constant based on the 45 measurements. Also, in the case of intermittent dosing, the dosing cycle and/or the dosing amount per dose may be adjusted. These chemical injection amount adjustments may be automatically adjusted by the chemical injection control unit 64 based on the measured value of the condensed water flowmeter 45, or may be changed by the person in charge of maintenance or the like.

If the condensed water of the combustion gas becomes acidic due to the dissolution of a trace amount of carbon dioxide contained in the combustion air and the nitrogen oxides of ppm order generated by combustion, etc., the proportion of the condensed water supplied to the boiler is added to the make-up water. Increase the amount of pH adjuster to be dosed. In the boiler 1 using non-carbon fuel, unlike city gas combustion gas, a large amount of carbon dioxide does not dissolve, so it can be dealt with by finely adjusting the dosage of the pH adjuster. In addition, since the condensed water contains almost no scale components, it is possible to eliminate or reduce the fine adjustment of the chemical amount for preventing the adhesion of scales and the like associated with the use of the condensed water. In this way, the chemical-feeding control unit 64 adjusts the chemical-feeding amount of the chemical-feeding device 51 based on the amount of condensed water. can be administered.

The blow control unit 65 performs blow control based on a blow rate (ratio between blow amount and water supply amount) set in advance or calculated from the water quality of the make-up water. The blow rate from the can body 12 is adjusted based on the percentage of condensed water. Blowing is performed to keep the concentration of impurities in the boiler water within the permissible range and to suppress scale adhesion and corrosion. can reduce the blow rate. For example, if the concentration blow rate is 10% under the condition that no condensed water is supplied (makeup water 100%), condensed water containing almost no scale or corrosive components is supplied to the make-up water by 10% for concentration. Blow rate is 9%. This reduces the amount of blow water discharged by concentrated blow (longer blow interval), reducing heat and water loss.

The supply amount of make-up water may be measured by providing a flow meter in the independent make-up water supply line 32 , or may be calculated based on the amount of non-carbon fuel supplied to the burner 11 . A condensed water supply amount calculator (not shown) is provided in the control device 60 to calculate the amount of condensed water supplied based on the amount of water produced by combustion calculated from the amount of non-carbon fuel burned. good too. For example, the amount of water produced by combustion is calculated from the amount of combustion of non-carbon fuel, the amount of water produced by combustion discharged as steam is calculated from the exhaust gas temperature downstream of the latent heat recovery device 21 (or the amount of condensed water is calculated), and the amount of water produced by combustion is calculated. Condensed water loss and other condensed water loss, etc. may be taken into account in the calculation. By using such a calculated value of the condensed water supply amount, it is possible to relatively easily optimize the concentration blow rate without the need for direct measurement by a flow meter of the condensed water, which has a high temperature and changes in temperature.

The boiler 1 having the above configuration can recover heat from the combustion gas to make-up water in the latent heat recovery device 21, and can also recover the heat of the condensed water generated in the latent heat recovery device 21, so it is excellent in energy efficiency. Furthermore, in the boiler 1, since condensed water with few impurities is supplied to the boiler body 12, blowing can be suppressed, and this can also improve energy efficiency.

<Second embodiment>
FIG. 5 is a schematic diagram showing the configuration of a boiler 1A according to the second embodiment of the invention. The boiler 1A includes a boiler body 10 having a burner 11 and a boiler body 12, an exhaust stack 20 attached to the boiler body 10 and having a latent heat recovery device 21 disposed therein, and moisture in the combustion gas in the latent heat recovery device 21. A condensed water tank 41A for storing condensed water condensed, a make-up water premixing line 46 for supplying make-up water to the condensed water tank 41A, and a mixed water obtained by mixing the condensed water and make-up water from the condensed water tank 41A. It has a condensed water supply line 42A that supplies the can body 12 through the latent heat recovery device 21, a chemical injection device 51 that injects chemicals into the make-up water, and a control device 60A that controls the operations of other components. The chemical injection device 51 only needs to be able to chemically inject the chemical into the mixed water formed by mixing the condensed water and the make-up water, and may be arranged so as to inject the chemical anywhere in the condensed water tank 41A and the condensed water supply line 42A.

The condensed water tank 41A stores condensed water generated in the latent heat recovery device 21 and makeup water supplied from the makeup water premixing line 46 . The condensed water supply line 42A supplies mixed water of condensed water and make-up water through the latent heat recovery device 21 to the boiler body 12 as boiler feed water. For this reason, the condensed water supply line 42A of the present embodiment is provided with a filtering device 43A and a condensed water pump 44A having a larger capacity than those of the first embodiment. In this embodiment, since the mixed water of condensed water and make-up water is supplied to the boiler body 12 via the latent heat recovery device 21, there is no condensed water supply line connecting the condensed water tank 41A and the boiler body 12. This can be simplified and the water level control of the condensed water tank 41A is facilitated.

The control device 60A includes a combustion control unit 61 that controls the amount of non-carbon fuel and combustion air supplied to the burner 11, and a mixing unit that controls the amount of mixed water supplied to the boiler body 12, that is, the operation of the condensed water pump 44A. It has a water control unit 66 , a chemical injection control unit 64A that controls the chemical injection device 51 , and a blow control unit 65A that controls the blow valve 16 .

The mixed water control unit 66 adjusts the supply amount of makeup water so that the water level in the water pipe 13 is kept within a certain range. For example, the water level in the condensed water tank may be maintained within a predetermined range by control using a ball tap or a water level sensor, and the mixed water control unit 66 may control the water level in the water pipe to be within the predetermined range according to the combustion state. . Moreover, it is preferable that the mixed water control unit 66 receives the condensed water from the recovery unit 22 preferentially over the supplementary water from the external water source in the condensed water tank 41A. For example, the water level at which the condensed water tank 41A starts receiving make-up water may be lower than the water level at which it starts receiving condensed water.

The chemical injection control unit 64A sets the proportionality constant of the flow rate proportional chemical injection based on the supply amount of the mixed water of the condensed water supply line 42A and the water quality of the make-up water, and the water quality change (decrease in scale component, Correct the constant of proportionality to reflect the pH drop, etc.). For example, the amount of water generated by combustion is calculated based on the chemical composition and amount of combustion of the non-carbon fuel, and the supply amount of condensed water is calculated by multiplying this amount of water by the recovery rate assumed in the latent heat recovery device 21. Furthermore, by subtracting the supply amount of this condensed water from the flow rate of the condensed water supply line 42A, the supply amount of makeup water is calculated, and the mixing ratio with the condensed water in the condensed water supply line 42A, which is representative of the predetermined period, is calculated. . The water quality of the condensed water can be measured in advance, or the water quality that does not contain scale components and is assumed to have a predetermined pH drop by adding a safety factor can be used. As a result, it is possible to perform appropriate chemical dosing without measuring the supply amount of condensed water and the water quality of the mixed water, which fluctuate depending on the combustion state of the boiler and the like. In addition, the chemical injection control unit 64A may perform intermittent chemical injection based on the calculation of the supply amounts of the make-up water and the condensed water and the estimation of the water quality of the condensed water supply line 42A.

Similarly, the blow control unit 65A also calculates the supply amount of condensed water based on the supply amount of non-carbon fuel, and adjusts the blow rate based on the calculated supply amount.

The boiler 1A of this embodiment can also recover the heat of the condensed water generated by the latent heat recovery device 21, so it is excellent in energy efficiency.

<Third Embodiment>
FIG. 6 is a schematic diagram showing the configuration of a boiler 1B according to the third embodiment of the invention. The boiler 1B includes a boiler body 10 having a burner 11 and a can body 12, an exhaust stack 20 attached to the boiler body 10 and having a latent heat recovery device 21B therein, and makeup water supplied to the can body 12. A make-up water tank 31 to be stored, a make-up water primary supply line 35 for supplying make-up water from the make-up water tank 31 to the latent heat recovery device 21B, and condensed water in which water in the combustion gas is condensed in the latent heat recovery device 21B and make-up water. A condensed water tank 41A to be stored, a condensed water supply line 42B for supplying mixed water of condensed water and make-up water from the condensed water tank 41A to the boiler body 12, and a chemical injection device 51 for injecting chemicals into the make-up water tank 31. , and a controller 60B that controls the operation of the other components.

The latent heat recovery device 21B of this embodiment is a water sprinkler that sprinkles make-up water in the flow path of the combustion gas. By sprinkling the makeup water, the combustion gas and the makeup water come into direct contact with each other, and the makeup water is heated. Further, as the combustion gas is cooled by the make-up water, water in the combustion gas is condensed to produce condensed water, and the mixed water of the make-up water and the condensed water at approximately the dew point temperature is recovered by the recovering unit 22 . Further, a demister may be provided in the exhaust stack 20 in order to suppress splashes of water spray and condensed water from being accompanied by the combustion gas.

The supplementary water primary supply line 35 is pressurized by a supplementary water pump 34B and supplied to the latent heat recovery device 21B. The condensed water supply line 42B directly supplies the mixed water of the make-up water and the condensed water recovered by the recovery unit 22 and stored in the condensed water tank 41A to the can body 12 .

The control device 60B includes a combustion control unit 61 that controls the amount of non-carbon fuel and combustion air supplied to the burner 11, a makeup water control unit 62 that controls the makeup water pump 34, and a mixing unit that controls the condensed water pump 44A. It has a water control unit 66 , a chemical injection control unit 64A that controls the chemical injection device 51 , and a blow control unit 65A that controls the blow valve 16 . For example, the make-up water control unit 62 controls the make-up water pump 34 so as to increase or decrease the amount of sprayed water according to the combustion state (for example, when the amount of exhaust gas is large, the amount of sprayed water is increased). Also, the mixed water control unit 66 controls the condensed water pump 44A so that the water level in the water pipe is within a predetermined range according to the combustion state.

The boiler 1B of the present embodiment is excellent in energy efficiency because the heat of the condensed water generated by the latent heat recovery device 21 can be recovered directly to make-up water. In addition, since the condensed water is collected and supplied to the boiler body 12 as mixed water with the make-up water, the piping configuration and control can be simplified.

<Fourth Embodiment>
FIG. 7 is a schematic diagram showing the configuration of a boiler 1C according to the fourth embodiment of the invention. The boiler 1C includes a boiler main body 10 having a burner 11 and a boiler body 12, an exhaust stack 20 attached to the boiler main body 10 and having a latent heat recovery device 21B therein, and moisture in combustion gas in the latent heat recovery device 21B. A condensed water tank 41A for storing condensed water and make-up water condensed, a make-up water premixing line 46 for supplying make-up water to the condensed water tank 41A, and a mixed water of the condensed water and make-up water from the condensed water tank 41A. A condensed water supply line 42B for supplying to the boiler body 12, a chemical injection device 51 for injecting chemicals into the condensed water tank 41A, and a mixed water of condensed water and makeup water from the condensed water tank 41A is supplied to the latent heat recovery device 21B. It has a mixed water supply line 71 and a controller 60C that controls the operation of other components.

The mixed water supply line 71 has a mixed water pump 72 that pressurizes the mixed water. The mixed water pump 72 operates according to the combustion state (for example, when the amount of exhaust gas is large, the amount of sprayed water is increased).

The boiler 1C of this embodiment has water circulation between the latent heat recovery device and the condensed water tank. Sufficient water is sprinkled for latent heat recovery without being restricted by the amount of water within the water level fluctuation range), and sufficient contact between the combustion gas and mixed water can be ensured, so even if the load fluctuates, the combustion gas It is possible to stably recover heat from

Although the preferred embodiments of the boiler according to the present invention have been described above, the present invention is not limited to the above-described embodiments and can be modified as appropriate.

As an example, the combination of the components of the above-described embodiments is an example, and the components of each embodiment can be replaced with the components of other embodiments.

In the above-described embodiment, the chemical feeding amount is adjusted based on the amount of condensed water supplied to the boiler body. The dosage may be determined in consideration of the measured value.

As in the above-described third and fourth embodiments, when a water sprinkler is used as a latent heat recovery device, the heat that lowers the temperature of the combustion gas to near the dew point by heat exchange with makeup water on the upstream side of the water sprinkler in the exhaust stack Additional exchangers may be added.

The boiler according to the invention may comprise further components not mentioned in the above embodiments.

Reference Signs List 1 boiler 10 boiler body 11 burner 12 can body 20

exhaust stack

21, 21B latent heat recovery device 22 recovery unit 31 makeup water tank 32 makeup water independent supply line 33 makeup water

raw supply line

34, 34B makeup water pump 35 makeup water

primary supply line

41 , 41A

Condensed water tank

42, 42A, 42B Condensed

water supply line

43,

43A Filtration device

44, 44A Condensed water pump 45 Condensed water flow meter 46 Make-up water premixing line 51

Chemical dosing device

60, 60A, 60B, 60C Control device 61 Combustion control unit 62 Make-up water control unit 63 Condensed

water control unit

64, 64A Chemical

injection control unit

65, 65A Blow control unit 66 Mixed water control unit 71 Mixed water supply line 72 Mixed water pump

Claims

a burner that burns a non-carbon fuel containing hydrogen and no carbon;
a can body for generating steam by the heat of the combustion gas generated by the burner;
a latent heat recovery device that recovers latent heat from the combustion gas that has passed through the can body to make-up water supplied to the can body;
a condensed water tank for storing condensed water obtained by condensing moisture in the combustion gas in the latent heat recovery device;
a condensed water supply line for supplying condensed water stored in the condensed water tank to the can;
boiler with
The latent heat recovery device is a heat exchanger that exchanges heat between makeup water supplied to the boiler body and combustion gas,
2. The boiler according to claim 1, further comprising a make-up water independent supply line for supplying make-up water to said boiler body through said latent heat recovery device independently of said condensed water supply line.
further comprising a make-up water premixing line that supplies make-up water to the condensed water tank;
The condensed water supply line supplies mixed water of condensed water and make-up water to the boiler via the latent heat recovery device,
2. The boiler according to claim 1, wherein said latent heat recovery device is a heat exchanger that exchanges heat between a mixture of condensed water and make-up water and combustion gas.
further comprising a makeup water primary supply line for supplying makeup water to the latent heat recovery device,
The latent heat recovery device is a sprinkler that sprinkles make-up water in the flow path of the combustion gas,
The condensed water tank collects make-up water sprinkled with the condensed water,
2. The boiler according to claim 1, wherein said condensed water supply line supplies mixed water of condensed water and make-up water to said boiler body.
a make-up water premixing line that supplies make-up water to the condensed water tank;
a mixed water supply line for supplying mixed water of condensed water and make-up water from the condensed water tank to the latent heat recovery device;
further comprising
2. The boiler according to claim 1, wherein said latent heat recovery device is a sprinkler for spraying mixed water of condensed water and make-up water in the flow path of combustion gas.
The boiler according to any one of claims 1 to 5, further comprising a blow control unit that adjusts the blow rate from said can body based on the respective supply amounts of condensed water and make-up water to said can body.
The boiler according to claim 6, wherein the blow control unit calculates the supply amount of condensed water based on the supply amount of non-carbon fuel.
The boiler according to any one of claims 1 to 7, wherein the condensed water supply line is equipped with a filtering device.
a chemical dosing device for dosing replenishment water;
a chemical injection control unit that controls the chemical injection amount of the chemical injection device;
further comprising
The boiler according to any one of claims 1 to 8, wherein said chemical feeding control unit adjusts the amount of chemical feeding based on the amount of condensed water supplied to said boiler body.
10. The boiler according to claim 9, wherein said chemical dosing control unit calculates a supply amount of condensed water based on a supply amount of non-carbon fuel.