JP2022185215A - Ammonia and hydrogen production system - Google Patents

Abstract

To efficiently and inexpensively produce ammonia and hydrogen by using discharged water of a combustion furnace plant comprising a combustion furnace and a boiler.SOLUTION: An ammonia and hydrogen production system 1 includes a boiler 20 generating steam by heat of a combustion furnace 11, an exhaust gas treatment device 13 performing exhaust gas treatment of the combustion furnace 11 and discharging exhaust gas treatment waste water F1, a separation device 10 separating boiler blow water F2 of the boiler 20 into ammonia-containing water F5 and treatment water F6, a water electrolysis device 32 electrolyzing the treatment water F6 to produce hydrogen F7, a hydrogen storage tank 33, an ammonia stripping device 44 radiating ammonia from the exhaust gas treatment waste water F1, and an ammonia water storage tank 51 storing ammonia water F8 containing the radiated ammonia. In the ammonia stripping device 44, the ammonia-containing water F5 is sprayed to a first position P1, and the exhaust gas treatment waste water F1 is sprayed to a second position P2 different from the first position P1.SELECTED DRAWING: Figure 1

Description

The present invention relates to a system for producing ammonia and hydrogen using wastewater from a combustion furnace plant comprising a combustion furnace and a boiler.

In recent years, the momentum for decarbonization as a countermeasure against global warming is increasing worldwide, and as a technology to reduce carbon dioxide (CO ₂ ) emissions, hydrogen (H ₂ ) and ammonia ( NH ₃ ) as a fuel is attracting attention. In Japan, for example, a technology has been developed in which a water electrolysis device is installed in a waste incinerator, hydrogen produced by the water electrolysis device is used to produce ammonia, and this ammonia is used as fuel for a gas engine or the like. (See Patent Document 1).

On the other hand, in plants such as waste incinerator plants, thermal power plants, and chemical plants, which are equipped with a combustion furnace and a boiler that generates steam from the heat of the combustion furnace (hereinafter referred to as "combustion furnace plant"), the nitrogen contained in the exhaust gas is In order to reduce oxides (NOx) and sulfur oxides (SOx), a chemical containing ammonia is supplied to the exhaust gas, and a chemical containing ammonia is used to adjust the pH value (pH value) of the water stored in the boiler. is used, it is known that a large amount of waste water containing ammonia and ammonia nitrogen (hereinafter referred to as "ammonia-containing waste water") is generated.
Devices for removing ammonia from ammonia-containing waste water include an ammonia stripping device, a cation exchanger (ion exchange resin), and the like (see Patent Documents 2 and 3).

Japanese Patent Application Laid-Open No. 2019-216501 Japanese Patent Application Laid-Open No. 2004-097901 Japanese Patent Application Laid-Open No. 2019-098206

In the technique of Patent Document 1, ammonia is synthesized from hydrogen generated in a water electrolysis device and nitrogen in the air. However, although a large amount of waste water containing ammonia exists in the combustion furnace plant, it is inefficient to produce ammonia using hydrogen produced by the water electrolyzer without utilizing it.
In the technique described in Patent Document 1, in order to reduce the temperature of the exhaust gas, a temperature reduction tower, which is a so-called scrubber, is installed upstream of the dust collector, and the waste water generated in the temperature reduction tower is supplied to the water electrolysis device. is doing. However, the water electrolyzer is a device that produces hydrogen using pure water as a raw material. The waste water cannot be directly supplied to the water electrolysis device.

Therefore, ammonia (NH ₄ OH), it is also conceivable to apply the techniques of Patent Documents 2 and 3.
However, the flow rate of boiler blow water is generally much smaller than that of flue gas treatment waste water. Therefore, the pH value (hydrogen ion exponent) of the mixture of the two is lower than the pH value of the boiler blow water.
When ammonia is obtained by stripping ammonia from the mixed liquid with a relatively low pH value using the technique of Patent Document 2, that is, an ammonia stripping device, the amount of ammonia stripped is reduced compared to when the pH value is high. . Therefore, it is necessary to increase the pH value of the mixed liquid by adding a large amount of an alkaline chemical (eg, strongly alkaline sodium hydroxide, etc.).
On the other hand, the ion exchange resin of Patent Document 3 is more expensive than the ammonia stripping device of Patent Document 2, and is not suitable for processing a large amount of the mixed liquid from the viewpoint of operating costs.
In other words, when ammonia is produced from ammonia-containing waste water in a combustion furnace plant using the techniques of Patent Document 2 and Patent Document 3, the operating cost of the combustion furnace plant is generally high.

An object of the present invention is to solve the above problems, and to provide an ammonia and hydrogen production system capable of efficiently and inexpensively producing ammonia and hydrogen using ammonia-containing waste water.

The ammonia and hydrogen production system of the present invention is applied to a combustion furnace plant, and includes a boiler that generates steam from the heat of the combustion furnace, an exhaust gas treatment device that treats exhaust gas from the combustion furnace, and discharges exhaust gas treatment wastewater. A separation device that separates the boiler blow water of the boiler into ammonia-containing water and treated water, a water electrolysis device that performs electrolysis using the treated water to produce hydrogen, a hydrogen storage tank that stores the hydrogen, It has a first ammonia stripping device for stripping ammonia from the exhaust gas treated wastewater, and an ammonia water storage tank for storing ammonia water containing the stripped ammonia, and the exhaust gas and the boiler contain ammonia or ammonia nitrogen. A chemical containing is supplied, the ammonia-containing water separated by the separation device is injected to the first position of the first ammonia stripping device, and the exhaust gas treatment wastewater discharged from the exhaust gas treatment device is the Viewed in the direction of flow of stripped ammonia, it is injected at a second location of said first ammonia stripping device that is different from said first location.

According to the ammonia and hydrogen production system of the present invention, boiler blow water, which is ammonia-containing waste water, is separated into ammonia-containing water and treated water, and the treated water is electrolyzed by a water electrolysis device to produce hydrogen. Ammonia-containing water and exhaust gas treatment wastewater, which is ammonia-containing wastewater, are injected to different positions of the ammonia stripping device when viewed in the direction of flow of the diffused ammonia, and ammonia is separately diffused from these. Ammonia water can be efficiently produced compared to the case where ammonia is diffused after mixing.
In addition, by injecting the chemicals to the separate positions, the supply amount of chemicals for raising the pH value can be reduced. Furthermore, the separator can be constructed at a low cost because it treats a small amount of boiler blow water instead of exhaust gas treatment wastewater.
Therefore, the ammonia and hydrogen production system of the present invention can efficiently and inexpensively produce ammonia and hydrogen using ammonia-containing waste water.

1 is a diagram showing an embodiment of an ammonia and hydrogen production system of the present invention; FIG. It is a figure which shows the modification of the ammonia and hydrogen production system of this invention.

Hereinafter, the ammonia and hydrogen production system of the present invention will be described with reference to FIGS. 1 and 2. FIG.
In the drawings, numerical symbols represent physical elements such as devices, parts, and parts related to the system in the embodiments and modifications of the present invention. Also, a symbol combining an alphabetic character F and a number represents a fluid such as liquid or gas generated in this system, and a symbol combining an alphabetic letter P and a number represents a position.
It should be noted that the examples and modifications shown below are merely examples, and are not intended to exclude various modifications and application of techniques that are not explicitly stated. Each configuration described below can be modified in various ways without departing from the scope of the invention. In addition, each of the following configurations can be selected or discarded as required except for the configurations essential to the present invention, or can be combined with known configurations.

[1. Example]
FIG. 1 is a block diagram showing an ammonia and hydrogen production system 1 of an embodiment.
The ammonia and hydrogen production system 1 includes a boiler 20 that generates steam from the heat of the combustion furnace 11, an exhaust gas treatment device 13 that treats the exhaust gas F10 of the combustion furnace 11 and discharges the exhaust gas treatment wastewater F1, and a boiler blow of the boiler 20. A separation device 10 that separates water F2 into ammonia-containing water (high-concentration ammonia-containing water) F5 and treated water F6, a water electrolysis device 32 that performs water electrolysis using the treated water F6 to produce hydrogen F7, and hydrogen A hydrogen storage tank 33 for storing F7, an ammonia stripping device 44 (first ammonia stripping device) for dispersing ammonia from the exhaust gas treatment wastewater F1, and an ammonia water storage tank 51 for storing ammonia water F8 containing the dissipated ammonia. and at least.

Ammonia and hydrogen production system 1 is applicable to a plant comprising a combustion furnace and a boiler that generates steam from the heat of the combustion furnace, that is, a combustion furnace plant, such as a waste incineration plant and a thermal power plant. , chemical plants, etc. However, the combustion furnace plant to which the ammonia and hydrogen production system 1 is applied must have at least the configuration essential to the present invention (the configuration described in the claims), but must include all the configurations shown in FIG. no.
Further, in the ammonia and hydrogen production system 1, all the components shown in FIG. 1 do not need to be placed on the same site, and multiple components shown in FIG. 1 may be placed on separate sites. In this case, the ammonia and hydrogen production system 1 may be configured by appropriately connecting transportation routes such as pipelines and automobiles.

Now, each configuration and effect of FIG. 1 will be described.
The combustion furnace 11 is a furnace for burning fuel to obtain heat. When the combustion furnace plant to which the present invention is applied is, for example, a waste incinerator plant, the fuel is generally waste (municipal waste, industrial waste, etc.), and in the case of thermal power plants and chemical plants In general, the fuel is coal, petroleum, natural gas, woody biomass, green fuel such as biogas produced by fermentation or the like. However, as the fuel for the combustion furnace 11, ammonia or hydrogen, for example, ammonia or hydrogen produced by the ammonia and hydrogen production system 1 may be used.
The exhaust gas F10 generated in the combustion furnace 11 sequentially flows through the flue as follows, and is released from the stack 15 to the atmosphere. That is, the exhaust gas F10 includes a temperature reduction tower (not shown) that reduces the temperature of the exhaust gas F10, a dust collector 12 (for example, a bag filter, an electric dust collector, etc.) that removes dust from the exhaust gas that has been reduced in temperature by the temperature reduction tower, and a dust collector. A wet exhaust gas treatment device 13 that removes harmful components such as nitrogen oxides (NOx) and sulfur oxides (SOx) from the exhaust gas that has been dust-removed by the device 12, and carbon dioxide from the exhaust gas from which the harmful substances have been removed by the exhaust gas treatment device 13. and a chimney 15 for releasing the exhaust gas from which carbon dioxide has been removed by the carbon dioxide separator 14 into the atmosphere.

Here, in order to reduce nitrogen oxides (NOx) and sulfur oxides (SOx), a chemical containing ammonia or ammonia nitrogen is supplied to the combustion furnace 11 or the flue. In the exhaust gas treatment device 13 having a desulfurization device, a large amount of exhaust gas treated waste water F1, which is ammonia-containing waste water, is discharged.
The exhaust gas treatment wastewater F1 flows through a third pipe having one end connected to the exhaust gas treatment device 13, that is, a third pipe which is a third flow path 43 described in detail later.
In addition, the carbon dioxide separation device 14 can utilize known techniques such as polymer separation membranes (carbon dioxide separation membranes) and amine solutions. The carbon dioxide separated by the carbon dioxide separator 14 is stored in the carbon dioxide storage tank 37 .

The boiler 20 is a device that uses the heat of the combustion furnace 11 to generate steam.
The boiler 20 includes a water purifier 27 that produces pure water from tap water, industrial water, etc., a chemical supply device 28 that adds chemicals such as pH value adjusters to the pure water produced by the water purifier, a steam drum 21 for storing pure water, an exhaust heat recovery device 22 such as a heat transfer tube or a superheating tube that turns the water stored in the steam drum 21 into steam with the heat of exhaust gas, and a steam drum generated by the exhaust heat recovery device 22 A steam turbine 23 that rotates an impeller with the steam supplied to 21, a generator 24 that generates power with the rotational force of the impeller of the steam turbine 23, and steam after rotating the impeller of the steam turbine 23 (waste steam F4). and a deaerator 26 that removes dissolved gases (oxygen, carbon dioxide, etc.) from the condensate generated in the condenser 25 and supplies it to the steam drum 21 .
The boiler blow water F2 is discharged as needed from the blow pipe 29 arranged below the steam drum 21 .

In consideration of corrosion resistance, the water stored in the steam drum 21 has a pH value of about 9 to 10 (for example, a pH value of about 10.3). Chemicals such as pH adjusters containing nitrogen are supplied. Therefore, the boiler blow water F2 is ammonia-containing waste water with a pH value of about 9-10.
The water stored in the steam drum 21 is pure water to which only a small amount of chemical is added, and does not contain impurities such as ash, so it is substantially the same as pure water. In addition, since the pH value of the flue gas treated wastewater F1 is generally about 6 to 9, the pH value of the boiler blow water F2 is equal to the pH value of the flue gas treated wastewater F1, or more than the pH value of the flue gas treated wastewater F1. is also big.
The amount of boiler blow water F2 is small compared to the amount of exhaust gas treatment waste water F1 generated in the exhaust gas treatment device 13 . For example, the amount of boiler blow water F2 may be about one-hundredth (1/100) to about one-tenth (1/10) of the amount of exhaust gas treated waste water F1.

The electric power generated by the generator 24 is used to operate various electric appliances (water electrolysis device 32, methanation device 35, ammonia stripping device 44, urea production device 52, etc.) in the ammonia and hydrogen production system 1. surplus electricity may be sold to the power company. The electric power is not sold to the electric power company, or the amount of electric power sold is small, and all or most of the electric power is supplied to various electric appliances arranged in the combustion furnace plant to which the ammonia and hydrogen production system 1 is applied. By designing accordingly, it is possible to construct a combustion furnace plant that is substantially self-sustaining.

The separation device 10 is supplied with at least a part of the boiler blow water F2 discharged from the steam drum 21 at any time, and separates it into the ammonia-containing water F5 (high-concentration ammonia-containing water) and the treated water F6. is. Of course, the entire amount of the boiler blow water F2 may be supplied to the separation device 10 as shown in FIG. 1 if it is possible in terms of design. Although not shown, if there is remaining boiler blow water that is not supplied to the separation device 10, the boiler blow water is treated in a general wastewater treatment facility 58, particularly an inorganic treatment device 60, which will be described later.
In the embodiment of FIG. 1, the separation device 10 is an ion removal device 30 (first ion removal device).

The ion remover 30 incorporates, for example, an RO membrane (reverse osmosis membrane) or an ion exchange resin. RO membranes are membranes that allow hydrogen ions (H ⁺ ) and hydroxide ions (OH ⁻ ) in water to pass through, while blocking the passage of other unwanted ions (such as Ca ²⁺ , Mg ²⁺ , Na ⁺ , etc.). be. The ion exchange resin is a gel-like synthetic resin bead that replaces unnecessary ions in water with hydrogen ions or hydroxide ions.
Therefore, the ion removal device 30, which is the separation device 10, is supplied with at least a part of the boiler blow water, and divides the boiler blow water into ammonia-containing water F5 containing not only ammonia and ammonia nitrogen but also other unnecessary ions, and treated water. It is a device that separates from F6.

Here, the pH value of the ammonia-containing water F5 generated by the ion removing device 30 becomes higher than the pH value of the boiler blow water F2, and also higher than the pH value of the exhaust gas treated waste water F1. For example, when the pH value of the boiler blow water F2 is about 9 to 10 and the pH value of the flue gas treatment wastewater F1 is about 6 to 9, the pH value of the ammonia-containing water F5 is greater than 10.5, specifically Typically, it can be from about 11.0 to about 13.0. Therefore, the ammonia-containing water F5 is high-concentration ammonia-containing water containing high-concentration ammonia or ammonia nitrogen.
In addition, it is generally said that in the ammonia stripping apparatus, the amount of ammonia released decreases when the pH value of the ammonia-containing water becomes 10.5 or less. Therefore, as will be described later, when the exhaust gas treated wastewater F1 is supplied to the ammonia stripping device 44, an alkaline chemical is appropriately supplied to the exhaust gas treated wastewater F1 from the alkaline chemical supply device 55, and the exhaust gas treated wastewater F1 is A pH value of 10.5 or higher is desirable.

The water electrolysis device 32 is a device that electrolyzes the treated water F6 generated by the separation device 10 to produce hydrogen F7. In general, a water electrolysis apparatus is supplied with water containing no impurities or very few impurities, so-called pure water or water substantially equivalent to pure water, and performs electrolysis. Therefore, the treated water F6 is pure water or water substantially equivalent to pure water. The hydrogen F7 produced by the water electrolysis device 32 is stored in the hydrogen storage tank 33.
The oxygen generated simultaneously with the hydrogen F7 during the electrolysis of the treated water F6 may be released into the atmosphere, supplied to the inside of the combustion furnace 11 as a combustion accelerator, or stored in an oxygen storage tank (not shown). may
In general, a water electrolysis apparatus is equipped with a heating device for heating room-temperature pure water or the like in order to perform electrolysis efficiently. However, the water electrolysis device 32 does not need to be equipped with the heating device. This is because the boiler blow water F2, which is the raw material of the water electrolysis device 32, has a high temperature, so the treated water F6 separated by the ion removal device 30 can be adjusted to a temperature higher than room temperature (about 70° C. to about 90° C.). . Therefore, the water electrolysis device 32 can efficiently produce hydrogen without the heating device, and is therefore cost-effective. Of course, the above-mentioned heating device may be added to the water electrolysis device 32 when it is necessary to further heat the treated water F6 having a temperature higher than the room temperature.

In principle, the distribution device 39 allows the ammonia-containing water F5 generated in the separation device 10 to flow only through the first flow path 41, and when the flow rate of the ammonia-containing water F5 is a predetermined flow rate or more, as an exception, It is a device that distributes and flows both of the second flow paths 42 .
The distribution device 39 of FIG. 1 comprises a reservoir (not numbered) for storing the ammonia-containing water F5 and a funnel 40 . The funnel 40 is placed at the reference water level in the reservoir. One end of a pipe serving as the first flow path 41 (hereinafter referred to as “first pipe”) is connected to the bottom surface of the storage tank. One end of a pipe (hereinafter referred to as a "second pipe") that forms a second flow path 42 is connected to the funnel 40, and the second pipe is arranged to penetrate through the bottom surface of the storage tank. The space between the second pipe and the bottom surface is sealed with resin or the like to prevent water leakage.
In the distributor 39 of FIG. 1, the ammonia-containing water F5 is supplied from above the storage tank while avoiding the funnel 40 . The ammonia-containing water F5 flows out from the first pipe, which is the first flow path 41, and is gradually stored in the storage tank when the flow rate of the ammonia-containing water F5 is greater than a predetermined flow rate. At this time, since the first pipe has a predetermined inner diameter, the flow rate of the ammonia-containing water F5 that continues to flow out from the first pipe is in principle constant.
Then, when the liquid level of the ammonia-containing water F5 stored in the storage tank reaches the reference water level, the stored ammonia-containing water F5 overflows the funnel 40 and flows from the second pipe, which is the second flow path 42. leak.

In addition, in the distribution device 39, the ammonia-containing water F5 continues to flow out from the first pipe even when it flows out from the second pipe. Also, the other end of the second pipe is connected to the third pipe described above, that is, the route of the third flow path 43 . Therefore, the ammonia-containing water F5 flowing out from the second pipe is mixed with the exhaust gas treatment waste water F1. However, in order to prevent the exhaust gas treatment wastewater F1 from flowing into the second pipe from the third pipe, a device such as a check valve that allows the flow direction to flow in one direction is installed.

The distribution device 39 does not have a configuration in which the funnel 40 is arranged, and in principle, the ammonia-containing water F5 generated in the separation device 10 is allowed to flow only through the first flow path 41, and when the flow rate of the ammonia-containing water F5 is a predetermined flow rate or more, may be any configuration as long as it is configured to distribute and flow to both the first channel 41 and the second channel 42 as an exception.
For example, the distribution device 39 has a first pipe and a second pipe separately connected to the bottom surface of the storage tank, a flow meter for measuring the flow rate of the boiler blow water F2, and a first solenoid valve installed in the first pipe. , receives information about the flow rate measured by the second solenoid valve installed in the second pipe and the flow meter, and if the flow rate of the boiler blow water F2 is less than or equal to the predetermined flow rate of the first flow path 41, the first solenoid valve A control device that opens the valve, closes the second solenoid valve, and opens both the first solenoid valve and the second solenoid valve when the flow rate of the boiler blow water F2 is greater than the predetermined flow rate of the first flow path 41 It is good also as a structure provided.

The ammonia stripping device 44 (first ammonia stripping device) sprays ammonia-containing water (exhaust gas treatment wastewater F1, ammonia-containing water F5) containing ammonia or ammonia nitrogen to the steam, and sprays with the heat of the steam. It is a device that dissipates ammonia from water that has been filtered. The steam used in the ammonia stripper 44 may be the waste steam F4 previously described. Steam having a higher temperature than the waste steam F4, for example, steam before rotating the impeller of the steam turbine 23 may be used. Excellent.
The ammonia stripping device 44 is composed of one vertically long stripping tower or a plurality of stripping towers continuously connected in series. A stripper column is a vertically upright hollow cylindrical vessel. Steam (waste steam F4) is supplied from below the container, and exhaust gas treated waste water F1 and ammonia-containing water F5 are sprayed from above. Then, the ammonium ions react with the hydroxide ions inside the diffusion tower to generate gaseous ammonia water F8 containing ammonia and water vapor.

In order to improve the yield of ammonia, the stripping column is generally configured in a multi-tiered manner in which a plurality of fillers and a plurality of trays are vertically dispersed.
In the ammonia stripping device 44 of FIG. 1, one stripping tower is used as an example, and the stripping tower is vertically partitioned into three stages with two trays 47 as an example. One diffusion tower may be partitioned into four or more stages with three or more trays 47 or the like.
The ammonia-containing water sprayed by the ammonia stripping device 44 comes into contact with the steam and dissipates ammonia. Diffusion becomes less efficient. Therefore, the increased water droplets are collected by the tray 47 and sprayed again as fine water droplets, thereby improving the yield of ammonia.
Specifically, one tray 47 is connected to one tank 48 , and the ammonia-containing water collected by the tray 47 is stored in the tank 48 . In addition, one sprayer 50 is installed below the tray 47 (however, when another tray 47 is arranged below the tray 47, below the tray 47 and above the other tray 47). Then, one pump 49 pressure-feeds the ammonia-containing water stored in the tank 48 to the sprayer 50 , so that the ammonia-containing water stored in the tank 48 is sprayed from the sprayer 50 .

Ammonia-containing water collected in the tray 47 has already dissipated some of the ammonia. Therefore, since the concentration of ammonia and ammonium nitrogen in the ammonia-containing water is lower than at the beginning, the position where the steam temperature is higher, that is, below the tray 47, in other words, the direction in which the diffused ammonia flows (the direction in which the steam flows) By spraying upstream of the tray 47 when viewed in the direction (also the direction), ammonia can be more efficiently diffused from the ammonia-containing water whose concentration is reduced.
Since the ammonia stripping apparatus 44 of FIG. 1 is configured to be partitioned into three stages, a set consisting of one tray 47, one tank 48, one pump 49, and one atomizer 50 is There are two sets in total.
The ammonia water F<b>8 produced by the ammonia stripping device 44 is discharged in a gaseous state from the upper portion of the ammonia stripping device 44 , cooled, and stored in the ammonia water storage tank 51 . Ammonia water F8 contains ammonia at a high concentration (eg, about 30 to about 50%).

The ammonia stripping device 44 further includes a first sprayer 45 connected to the other end of the first pipe inside the stripping tower and spraying the high-concentration ammonia-containing water F5. In addition, the ammonia stripping device 44 is connected to the other end of the third pipe, and includes a second sprayer 46 that sprays the exhaust gas treatment wastewater F1 in principle, and as an exception a mixture of the exhaust gas treatment wastewater F1 and the high-concentration ammonia-containing water F5. Prepare.
The first sprayer 45 and the second sprayer 46 are arranged at positions different from each other when viewed in the direction of flow of the diffused ammonia, that is, the direction of steam flow. Specifically, the first position P1 where the first sprayer 45 is arranged in the diffusion tower is downstream of the second position P2 where the second sprayer 46 is arranged. In other words, when the first sprayer 45 and the second sprayer 46 are arranged in one diffusion tower as shown in FIG. 1, the first position P1 is higher than the second position P2. When a plurality of stripping towers are connected in series to form the ammonia stripping device 44, and the first sprayer 45 and the second sprayer 46 are arranged in separate stripping towers, the first position P1 is not necessarily above the second position P2. However, even in this case, the first position P1 where the first sprayer 45 is arranged in the diffusion tower is the second position P1 where the second sprayer 46 is arranged when viewed in the direction of flow of the diffused ammonia, that is, the direction of steam flow. It is on the downstream side of the position P2.
In the ammonia stripping device 44 of FIG. 1, as an example, of the three-stage regions (top, middle, and bottom) formed in one stripping tower, the first sprayer 45 is the uppermost step, and the second sprayer 46 is the They are arranged in the middle row, that is, they are arranged in different rows. At the bottom, the water droplets that have grown larger are collected and stored as residual water. Also, in the lowest stage, steam (waste steam F4) is supplied from above the residual water.

Generally, in the ammonia stripping device, the higher the steam temperature and the higher the pH value of the ammonia-containing water, the better the ammonia stripping performance. Furthermore, in order to efficiently dissipate ammonia in a multi-stage configuration as described above, it is desirable to effectively utilize all stages.
Here, in one stripping column, the highest steam temperature is upstream, that is, the lowermost stage, and the lowest steam temperature is downstream, that is, the uppermost stage.
The high-concentration ammonia-containing water F5 sprayed from the first sprayer 45 is more concentrated than the exhaust gas treatment wastewater F1 sprayed from the second sprayer 46, or the mixture of the exhaust gas treatment wastewater F1 and the high-concentration ammonia-containing water F5. High pH value.
Therefore, the first sprayer 45, which sprays the high-concentration ammonia-containing water F5 with a sufficiently high pH value, can effectively dissipate ammonia even if the steam temperature is somewhat low, so it is arranged at the top. .
On the other hand, the second sprayer 46 for spraying ammonia-containing water (exhaust gas treatment wastewater F1 or a mixture of exhaust gas treatment wastewater F1 and high-concentration ammonia-containing water F5) having a pH value lower than that of the high-concentration ammonia-containing water F5 is When placed at the same position as the first sprayer 45 (at the same position in the uppermost stage and in the vertical direction), the ammonia-containing water sprayed from the first sprayer 45 and the second sprayer 46 is mixed, the pH value decreases, and the ammonia diffusion performance may decrease. Therefore, the second sprayer 46 is installed at the upstream second position P2 where the steam temperature is higher than the first position P1 of the first sprayer 45 . In FIG. 1, the second sprayer 46 is installed in the middle stage (stage different from the uppermost stage), which is a region where the steam temperature is higher than the uppermost stage where the first sprayer 45 is installed, and the ammonia-containing water sprayed from the second sprayer 46 By compensating for the low pH value of (exhaust gas treatment wastewater F1, or a mixed solution of exhaust gas treatment wastewater F1 and high-concentration ammonia-containing water F5) with a high steam temperature, the ammonia diffusion performance is improved comprehensively. .
Here, in FIG. 1, the first atomizer 45 and the second atomizer 46 are installed in different stages, but the same effect can be obtained even if they are installed in the same stage as long as the positions are different from each other in the vertical direction in the ammonia stripping apparatus. can be obtained. That is, ammonia can be effectively diffused separately from the high-concentration ammonia-containing water F5 with a high pH value and the ammonia-containing water with a lower pH value by utilizing the difference in steam temperature.

Since the ammonia-containing water sprayed from the second sprayer 46 has a lower pH value than the high-concentration ammonia-containing water F5, the alkaline chemical supply device 55 supplies the alkaline chemical to the third flow path 43, that is, the third pipe. (eg, sodium hydroxide, NaOH, etc.) may be supplied to increase the pH value. However, since the first sprayer 45 and the second sprayer 46 are arranged as described above, the pH value of the ammonia-containing water is slightly higher than 10.5, which is the pH value at which ammonia can be effectively diffused. It is not necessary to make the pH value equal to that of the high-concentration ammonia-containing water F5. Therefore, compared to the case where the pH value of the ammonia-containing water sprayed from the second sprayer 46 is made equal to the pH value of the high-concentration ammonia-containing water F5, the amount of alkaline chemicals can be reduced.

By the way, based on the above idea, when the pH value of the ammonia-containing water is made higher than the pH value of the high-concentration ammonia-containing water F5 by supplying an alkaline chemical, etc., the first sprayer 45 The other end of the three pipes may be connected and the other end of the first pipe may be connected to the second sprayer 46 .
In any case, high-concentration ammonia-containing water F5 and ammonia-containing water (exhaust gas treated wastewater F1, or mixed solution of exhaust gas treated wastewater F1 and high-concentration ammonia-containing water F5) are injected to separate positions of the ammonia stripping device. do. That is, in the ammonia stripping device, among these two ammonia-containing waters, the ammonia-containing water with a low pH value is upstream and the ammonia-containing water with a high pH value is downstream, in other words, at different positions or different from each other in the vertical direction. Since the ammonia is injected in stages and the ammonia is diffused separately from these, the ammonia water F8 can be produced efficiently compared to the case where these are mixed and then sprayed.

Further, when the high-concentration ammonia-containing water F5 flows out to the second flow path 42 by the distribution device 39, the second sprayer 46 receives the exhaust gas treatment wastewater F1 and the high-concentration ammonia-containing water through the third flow path 43. Since the mixed liquid of F5 is sprayed, the pH value of the mixed liquid becomes higher than when only the exhaust gas treatment waste water F1 flows through the third flow path 43 . Therefore, the amount of alkaline chemicals supplied to the third channel 43 by the alkaline chemicals supply device 55 can be reduced.
Furthermore, in this case, the flue gas treatment wastewater F1 contains scale components such as magnesium and calcium, but the high-concentration ammonia-containing water F5, which contains almost no scale components, is mixed with the flue gas treatment wastewater F1, so that the scale is integrated into the exhaust gas treatment wastewater F1. Since the concentration of the component is diluted, deposition of scale inside the ammonia stripping device 44 can be suppressed. Therefore, maintenance of the ammonia stripping device 44 can be facilitated.
The pH value of the high-concentration ammonia-containing water F5 sprayed from the first sprayer 45 is greater than 10.5, for example, about 11 to about 13, so there is no need to add an alkaline chemical.
In addition, the residual water F9 stored in the lowest stage of the ammonia stripping device 44 is supplied to a general waste water treatment facility 58 equipped with an inorganic treatment device 60 that performs at least inorganic water treatment, and after water treatment , for example, can be released.

In the embodiment, at least part of the boiler blow water F2 is used as a raw material for the water electrolysis device 32, so the total amount of ammonia-containing waste water is reduced compared to when it is not used as a raw material. Therefore, not only is the load of water treatment in the general wastewater treatment facility 58 reduced, but also the size of the ion removal device 30 can be reduced, so that the overall inexpensive ammonia and hydrogen production system 1 can be constructed.
Here, in addition to the inorganic treatment device 60 , the comprehensive wastewater treatment facility 58 may be provided with an organic treatment device 59 upstream of the inorganic treatment device 60 .
The organic treatment equipment 59 is a wastewater treatment facility in which biological treatment (wastewater treatment by the action of microorganisms) is carried out and which includes a nitrification tank, a denitrification tank, an aeration tank, and the like. When the general wastewater treatment facility 58 is equipped with the organic treatment device 59, the general wastewater treatment facility 58 can also treat organic wastewater such as domestic wastewater generated in the combustion furnace plant.

The hydrogen F7 stored in the hydrogen storage tank 33, the carbon dioxide F3 stored in the carbon dioxide storage tank 37, and the ammonia water F8 stored in the ammonia water storage tank 51 can be used for various purposes.
For example, the ammonia and hydrogen production system 1 may supply hydrogen F7 as a fuel to the hydrogen utilization equipment 34 such as a fuel cell, a hydrogen gas turbine, and a hydrogen gas engine, or may supply the hydrogen F7 to the methanation device 35 as a methanation raw material. may be supplied.
Further, the ammonia and hydrogen production system 1 may supply carbon dioxide F3 to the methanation device 35 as a raw material for methanation or to the urea production device 52 as a raw material for urea production. The ammonia and hydrogen production system 1 supplies carbon dioxide F3 to a carbon dioxide utilization facility 38 such as a plant factory that produces plants (plants, algae, flowers, vegetables, etc.) by photosynthesis, a greenhouse for cultivation, and a tank for cultivation. good too.
The ammonia and hydrogen production system 1 may supply the ammonia water F8 to the urea production device 52 as a raw material for producing urea, or a chemical plant, an ammonia gas turbine, an ammonia gas engine, etc. that produce chemical products using ammonia as a raw material. may be supplied to the ammonia utilization facility 54. The ammonia and hydrogen production system 1 may spray the ammonia water F8 as a denitration agent into the combustion furnace and the flue of the combustion furnace plant.
Furthermore, the ammonia and hydrogen production system 1 can be used in buildings and facilities that use methane produced by the methanation device 35 as fuel (city gas), gas turbines that burn methane to generate power, gas engines, and the like. It may be supplied to the methane utilization facility 36 .
The ammonia and hydrogen production system 1 can be used in a chemical plant that uses urea produced in the urea production device 52, for example, the heat of the steam produced in the boiler 20 and urea to produce chemical products, or a plant that uses urea as a fertilizer. You may supply to the urea utilization equipment 53, such as a factory.

[2. Modification]
FIG. 2 is a block diagram showing a modified ammonia and hydrogen production system 1'.
The main difference between the embodiment and the modification is the configuration of the separation device. In the example, the separation device 10 consisted of the ion removal device 30 only. However, in the modification, the separation device 10' includes an ammonia stripping device 56 (second ammonia stripping device) that strips ammonia from the boiler blow water F2 with steam to release ammonia-containing water F5, and an ammonia stripping device 56 An ion removing device 57 (second ion removing device) for separating the remaining water F11 into ion-containing waste water F12 containing unnecessary ions and treated water F6 not containing unnecessary ions.
In the modified example, the same reference numerals are given to the same configurations as those described in the embodiments, and the description of the configurations and effects will be omitted as appropriate.

The ammonia stripping device 56 (second ammonia stripping device) has the same configuration as the ammonia stripping device 44 (first ammonia stripping device), and may have one stripping tower formed in multiple stages, or a plurality of stripping towers. The stripping towers may be connected in series. Although the ammonia stripping device 44 (first ammonia stripping device) has three stages, the ammonia stripping device 56 (second ammonia stripping device) may have the same number of stages. , a different number of stages (two stages, four stages, five or more stages, etc.).
When the ammonia stripping device 56 (second ammonia stripping device) is formed by one stripping tower, the boiler blow water F2 is sprayed from a sprayer (not shown) provided on the uppermost stage of the stripping tower. On the other hand, steam (waste steam F4) is supplied to the lowest stage of the stripping tower. The gaseous ammonia-containing water F5 containing the diffused ammonia and water vapor is generated by the contact between the steam and the sprayed boiler blow water F2 inside the stripping tower.

The ammonia-containing water F5 produced by the separator 10' is ammonia water, and unlike the separator 10 in the embodiment, does not contain unnecessary ions other than ammonia and ammonia nitrogen. That is, the ammonia-containing water F5 produced by the separator 10' does not contain scale components such as magnesium and calcium.
Therefore, when the ammonia-containing water F5 flows through the second flow path 42 by the distribution device 39 and is mixed with the exhaust gas treatment waste water F1 in the third flow path 43, the concentration of the scale component in the mixed liquid is diluted more than in the embodiment. Therefore, it is possible to more effectively suppress the deposition of scale inside the ammonia stripping device 44 . Therefore, in the modification, maintenance of the ammonia stripping device 44 can be made easier than in the embodiment.

The ion remover 57 (second ion remover) has the same configuration as the ion remover 30 (first ion remover), and incorporates an RO membrane (reverse osmosis membrane) and an ion exchange resin.
The ion-containing waste water F12 separated by the ion removing device 57 (second ion removing device) is supplied to the inorganic treatment device 60 of the comprehensive waste water treatment facility 58 and subjected to water treatment.

1, 1' ammonia and hydrogen production system 10, 10' separation device 11 combustion furnace 12 dust collector 13 exhaust gas treatment device 14 carbon dioxide separation device 15 chimney 20 boiler 21 steam drum 22 exhaust heat recovery device 23 steam turbine 24 generator 25 Condenser 26 Deaerator 27 Pure water device 28 Chemical supply device 29 Blow pipe 30 Ion remover (first ion remover)
32 Water electrolysis device 33 Hydrogen storage tank 34 Hydrogen utilization equipment 35 Methanation device 36 Methane utilization equipment 37 Carbon dioxide storage tank 38 Carbon dioxide utilization equipment 39 Distributor 40 Funnel 41 First channel 42 Second channel 43 Third channel 44 Ammonia stripping device (first ammonia stripping device)
45 First sprayer 46 Second sprayer 47 Tray 48 Tank 49 Pump 50 Sprayer 51 Ammonia water storage tank 52 Urea production device 53 Urea utilization facility 54 Ammonia utilization facility 55 Alkaline chemical supply device 56 Ammonia stripping device (second ammonia stripping device )
57 ion remover (second ion remover)
58 General wastewater treatment facility 59 Organic treatment equipment 60 Inorganic treatment equipment P1 First position P2 Second position F1 Exhaust gas treatment wastewater F2 Boiler blow water F3 Carbon dioxide F4 Steam (waste steam)
F5 Ammonia-containing water (high-concentration ammonia-containing water)
F6 Treated water (pure water)
F7 Hydrogen F8 Ammonia water F9 Residual water F10 Exhaust gas F11 Residual water F12 Ion-containing wastewater

Claims (7)

Applied in combustion furnace plant,
a boiler that generates steam from the heat of the combustion furnace;
an exhaust gas treatment device for treating exhaust gas from the combustion furnace and discharging exhaust gas treatment wastewater;
A separation device for separating the boiler blow water of the boiler into ammonia-containing water and treated water;
a water electrolysis device that performs electrolysis using the treated water to produce hydrogen;
a hydrogen storage tank that stores the hydrogen;
a first ammonia stripping device for stripping ammonia from the exhaust gas treated wastewater;
an ammonia water storage tank for storing ammonia water containing the diffused ammonia;
A chemical containing ammonia or ammonia nitrogen is supplied to the exhaust gas and the boiler,
the ammonia-containing water separated by the separation device is injected into a first position of the first ammonia stripping device;
The exhaust gas treatment wastewater discharged from the exhaust gas treatment device is injected into a second position of the first ammonia stripping device different from the first position when viewed in the direction of flow of the diffused ammonia and hydrogen. manufacturing system. The ammonia-containing water separated by the separation device is passed through a first channel having a predetermined allowable flow rate, and when the ammonia-containing water exceeds the predetermined allowable flow rate, the exceeding flow rate is further provided through a second channel. death,
The ammonia-containing water in the first flow path is injected to the first position,
2. The ammonia and hydrogen production system according to claim 1, wherein the ammonia-containing water in the second flow path is mixed with the exhaust gas treatment wastewater and injected to the second position. The first ammonia stripping device is composed of one vertically long stripping tower or a plurality of stripping towers connected in series,
3. The ammonia and hydrogen production system according to claim 2, wherein the first position is downstream of the second position when viewed in the direction of flow of the dissipated ammonia. The separation device is
a first ion removal device for removing unnecessary ions from the boiler blow water to obtain the treated water;
or,
A device comprising: a second ammonia stripping device for stripping ammonia from the boiler blow water; and a second ion removal device for removing the unnecessary ions from the water remaining in the second ammonia stripping device to produce the treated water. An ammonia and hydrogen production system according to claim 3. a carbon dioxide separator that separates carbon dioxide from the exhaust gas;
a carbon dioxide storage tank for storing the separated carbon dioxide;
5. The ammonia and hydrogen production system according to claim 4, further comprising a methanation device that methanates the hydrogen stored in the hydrogen storage tank and the carbon dioxide stored in the carbon dioxide storage tank to produce methane. . 6. The ammonia and hydrogen production system according to claim 5, further comprising a urea production device that produces urea using the carbon dioxide stored in the carbon dioxide storage tank and the ammonia water stored in the ammonia water storage tank. The ammonia and hydrogen production system according to any one of claims 1 to 6, wherein the combustion furnace plant is any one of a waste incinerator plant, a thermal power plant, or a chemical plant.

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