TWI812238B - Hydrogen and ammonia production system - Google Patents

Abstract

A hydrogen and ammonia production system (1) is applied to a plant (10) having a boiler (16) and an exhaust-gas treatment device (14). The boiler (16) discharges boiler blow water (F3) and the exhaust-gas treatment device (14) discharges sewage (F1) after exhaust-gas treatment. The hydrogen and ammonia production system (1) includes a first ammonia recovery device (21), a second ammonia recovery device (22), an ion removal device (27), and a water electrolysis device (28). The first ammonia recovery device (21) generates first condensed ammonia water (F4) through stripping treatment for the sewage (F1). The second ammonia recovery device (22) generates second condensed ammonia water (F8) through stripping treatment for the boiler blow water (F3) and the first condensed ammonia water (F4). The ion removal device (27) divides discharged water (F9) of the second ammonia recovery device (22) into ion-concentrated water (F10) and filtered water (F11). The ion-concentrated water (F10) serves as alkali source for effluent processing of the plant (10). The water electrolysis device (28) generates hydrogen (F12) through electrolysis of the filtered water (F11).

Description

Hydrogen and ammonia production system

The present invention relates to a system for producing hydrogen and ammonia by utilizing waste water from a combustion device including a combustion chamber and a boiler.

Conventionally, in order to remove ammonia contained in the wastewater of combustion equipment, methods based on ion exchange and methods based on gas stripping have been known. The method described in Patent Document 1 is to allow boiler wastewater to pass through a cation exchanger to capture ammonia using the cation exchanger, and to obtain ammonia-concentrated wastewater by regenerating the cation exchanger. In the regeneration treatment of the cation exchanger, chemicals such as hydrochloric acid, sulfuric acid, and sodium hydroxide are added. Patent Document 1 also describes that ammonia-concentrated wastewater is introduced into an ammonia recovery device, and ammonia is transferred to the gas phase by stripping to be recovered as ammonia gas.

The method described in Patent Document 2 is to strip the ammonia-containing wastewater (drainage from a flue gas desulfurization device) containing hardness components by removing the hardness before introducing the ammonia-containing wastewater into the gas stripping device (ammonia stripping tower). Ingredients removed. First, alkali is added to ammonia-containing drainage water to adjust the pH (hydrogen ion concentration index) to 8 to 14. Then, a coagulant is added to remove the hardness components that have precipitated as precipitates. The clarified drainage water without sediment is supplied to the gas stripping device after adjusting the pH by adding acid, and ammonia gas is recovered through gas stripping. [Prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2019-098206 [Patent Document 2] Japanese Patent Application Publication No. 2007-175673

[Problem to be solved by the invention]

In the technology of Patent Document 1, a large amount of chemicals must be used to regenerate the cation exchanger, that is, to remove the ammonia captured by the cation exchanger, and the cost of obtaining concentrated ammonia wastewater is high. Also in the technology of Patent Document 2, a large amount of drugs must be used to adjust the pH, and the problem of drug cost cannot be solved. Moreover, if the two are mixed and then treated, the scale component of the exhaust gas treatment water will increase and the ammonia concentration of the boiler drainage water will decrease, so a large amount of pre-treatment chemicals must be added. Therefore, according to the existing technology, the valuable substances contained in the equipment drainage cannot be efficiently recovered.

The present invention was developed in view of the above-mentioned problems, and its purpose is to provide a hydrogen and ammonia production system that can efficiently and cheaply generate valuable substances from the drainage of equipment. [Technical means to solve problems]

The hydrogen and ammonia production system of the present invention is an organic or inorganic device equipped with a first ammonia recovery device, a second ammonia recovery device, an ion removal device, a water electrolysis device, and the above-mentioned equipment in a facility equipped with a boiler and an exhaust gas treatment device. drainage treatment device, The aforementioned boiler uses the heat of the combustion furnace or combustion chamber to generate steam and discharge boiler water. The aforementioned exhaust gas treatment device processes the exhaust gas generated from the aforementioned combustion furnace or the aforementioned combustion chamber and discharges the exhaust gas treatment wastewater, The above-mentioned first ammonia recovery device performs a stripping process on the above-mentioned exhaust gas treatment wastewater to recover ammonia and produce a first ammonia concentrated liquid, The second ammonia recovery device performs a stripping process on the first ammonia concentrate and the boiler wastewater to recover ammonia and produce a second ammonia concentrate, The ion removal device is configured to pass the boiler wastewater discharged from the second ammonia recovery device and separate it into filtered water and an ion concentrate containing residual alkali components, The aforementioned water electrolysis device electrolyzes the aforementioned filtered water to produce hydrogen, The organic or inorganic wastewater treatment device of the above-mentioned equipment is input using the above-mentioned ion concentrated liquid as an alkali source. [Effects of the invention]

According to the hydrogen and ammonia production system of the present invention, ammonia-containing wastewater, that is, waste gas treatment wastewater, is subjected to gas stripping treatment to recover the first ammonia concentrated liquid, and the first ammonia concentrated liquid and ammonia-containing wastewater, that is, boiler wastewater, are subjected to gas stripping treatment. The second ammonia concentrate can be recovered from boiler drainage through extraction treatment. Compared with treating these wastewaters individually to recover ammonia, or mixing these wastewaters for treatment, the amount of necessary chemicals can be reduced and the cost can be reduced. In addition, the filtered water obtained from the boiler wastewater remaining after recovering the second ammonia concentrated liquid using an ion removal device can be subjected to water electrolysis to produce hydrogen. Therefore, the hydrogen and ammonia production system of the present invention can efficiently and cheaply generate valuable substances from the ammonia-containing wastewater of the equipment.

Hereinafter, the hydrogen and ammonia production system of the present invention will be described with reference to FIGS. 1 to 4 . In the present invention, when there is no need to distinguish between ionic form and molecular form, the term "ammonia" includes both ammonia molecules and ammonium ions. Therefore, "ammonia-containing drainage water" also includes drainage water containing ammonia in the form of ammonium ions. In the drawings, simple numerical symbols represent physical elements such as devices, parts, and locations related to the system in the embodiments and modifications of the present invention. The symbol composed of the English letter F and numbers represents the fluid (Fluid) produced in this system, such as liquid and gas, and the symbol composed of the English letter P and numbers represents the position (Position). In addition, the embodiments and modifications shown below are only illustrations after all, and do not exclude the application of various modifications and techniques not explicitly stated. Each of the following structures can be implemented with various modifications without departing from the spirit thereof. In addition, each of the following components, except the essential components of the present invention, can be selected or combined with known components as needed.

[1.Example] [A.Composition] FIG. 1 is a block diagram showing the hydrogen and ammonia production system 1 of the embodiment. The hydrogen and ammonia production system 1 includes equipment 10 , a valuable substance production facility 20 , and an integrated wastewater treatment device 40 . The equipment 10 is equipped with at least a boiler 16 that generates steam using the heat of the combustion chamber (or combustion furnace) 11, and an exhaust gas treatment device 19 that processes the exhaust gas from the combustion chamber 11 and discharges the exhaust gas treatment wastewater F1. The valuable substance generation facility 20 at least includes an ammonia recovery device 21 that performs a stripping process on the waste gas treatment wastewater F1 of the facility 10 to recover the ammonia contained therein to produce a first ammonia concentrate F4, and an ammonia recovery device 21 that performs a stripping process on the waste gas treatment wastewater F1 of the facility 10. F3 and the first ammonia concentrated liquid F4 are stripped together to produce a second ammonia concentrated liquid F8, a second ammonia recovery device 22, and an ion removal device 27 that removes residual alkali components from the waste water F9 of the second ammonia recovery device 22. , and a water electrolysis device 28 that performs water electrolysis on filtered water F11 from which alkali components have been removed to produce hydrogen F12. The integrated wastewater treatment device 40 is equipped with an organic and inorganic wastewater treatment device. The organic and inorganic wastewater treatment device uses the alkali component removed by the ion removal device 27, that is, the ion concentrate F10 as an alkali source, and discharges it from the equipment 10. Equipment drainage F16 is processed until it can be discharged. The equipment 10 can be used as long as it has a combustion chamber and a boiler that generates steam using the heat of the combustion chamber, that is, a combustion equipment. For example, it can be used in various types of equipment such as waste incineration equipment, thermal power generation equipment, and chemical equipment. equipment. However, for the equipment using the hydrogen and ammonia production system 1, it is not necessary to arrange all the components in Figure 1 at the same site. A plurality of components in Figure 1 can be placed at different sites. In this case, the hydrogen and ammonia production system 1 may be configured by suitably connecting transportation routes such as pipelines and automobiles. The valuable substance generation facility 20 and the comprehensive drainage treatment device 40 may be arranged as an accessory facility to the facility 10 in the same site as the facility 10, or they may be placed in different sites and suitably connected with transportation routes such as pipelines and automobiles. Constitute a hydrogen and ammonia production system 1.

Next, each structure and effect of FIG. 1 will be described. Regarding the device 10, the combustion chamber 11 (or combustion furnace) is a facility for burning fuel. When the equipment 10 is, for example, a waste incineration equipment, generally speaking, the fuel is waste (municipal garbage, industrial waste), and when the equipment 10 is a thermal power generation equipment or a chemical equipment, generally speaking, the fuel is coal. , oil, natural gas, wood-based biomass, green fuels using biomass gas generated by fermentation, etc. In addition, as the fuel of the combustion chamber 11, ammonia and hydrogen, such as ammonia and hydrogen produced in the ammonia production system 1, can also be used. There are also cases where the combustion chamber 11 is provided as an accessory facility to the boiler 16 described below (for example, it is installed in the boiler 16).

The exhaust gas generated in the combustion chamber 11 flows sequentially through the flue as follows, and is discharged from the chimney 15 to the atmosphere. That is, the exhaust gas flows through the exhaust gas treatment device 19 and the chimney 15 in sequence. The exhaust gas treatment device 19 at least includes a dust collecting device 13 for removing dust from the exhaust gas, and a moisture absorber for removing harmful components such as sulfur oxides (SOx) from the exhaust gas after being dusted by the dust collecting device 13 using a method such as a lime plaster method. type processing device 14. The chimney 15 discharges the waste gas from which harmful components have been removed into the atmosphere. Here, in order to reduce nitrogen oxides (NOx) between the combustion chamber 11 and the wet treatment device 14, a chemical containing ammonia or ammonia nitrogen (denitrification) as a reducing agent for nitrogen oxides is supplied from the ammonia supply device 12. agent). Ammonia-containing wastewater, that is, exhaust gas treatment wastewater F1 is discharged from the wet treatment device 14 . In addition, the exhaust gas treatment wastewater F1 contains scale components of Ca ²⁺ and Mg ²⁺ . The ammonia concentration of the waste gas treatment water F1 is 50 to 50,000 mg/L, preferably 1,000 to 20,000 mg/L, and more preferably about 2,000 to 10,000 mg/L. The discharged exhaust gas treatment wastewater F1 is introduced into the first ammonia recovery device 21 of the valuable substance generation facility 20 described later. The exhaust gas treatment wastewater F1 can be stored in a wastewater storage tank (not shown) and then introduced into the first ammonia recovery device 21 .

The boiler 16 is a device that recovers heat from the combustion chamber 11 and generates steam F2. The boiler 16 system is equipped with a pure water production device 50 for producing pure water from tap water, industrial water, etc., an additive supply device 51 for adding additives such as a pH adjuster to the produced pure water, and a pure water (boiler) to which the chemical is added. Water) is stored in the steam drum 52, and the heat recovery device 53, which uses the heat of the exhaust gas to heat the boiler water stored in the steam drum 52 into steam F2, uses heat transfer tubes, superheating tubes, etc., and utilizes the heat generated in the heat recovery device 53 and The steam turbine 54 rotates the impeller of the steam stored in the steam drum 52, and the generator 55 generates electricity using the rotational force of the impeller of the steam turbine 54. The steam (exhaust steam) rotated by the impeller of the steam turbine 54 is restored to The water rehydration device 56 and the deaerator 57 remove dissolved gas from the rehydration water generated in the water rehydration device 56 and supply it to the steam drum 52 . Examples of the types of chemicals added here include boiler compounds, corrosion inhibitors (oxygen scavengers), scale inhibitors, etc., and contain at least ammonia for preventing corrosion. The boiler 16 has a mechanism for blowing part of the boiler water to the outside through a drainage pipe in order to prevent various components contained in the boiler water from being concentrated. The boiler water discharged to the outside of the boiler 16 is called boiler drainage F3. Boiler wastewater F3 is wastewater containing ammonia supplied from an additive (ammonia-containing wastewater), and is introduced into the second ammonia recovery device 22 of the valuable substance generation facility 20 described below. Considering corrosion resistance, the pH value of the water stored in the steam drum 52 is about 9 to 10 (for example, the pH value is about 10.3), so the pH value of the boiler drainage F3 is about 9 to 10. The boiler wastewater F3 may be stored in a wastewater storage tank (not shown) and then introduced into the second ammonia recovery device 22. The electric power generated by the generator 55 can be used as electric power in the hydrogen and ammonia production system 1, and the remaining electric power can be sold to the electric power company. The steam F2 can be used in heat utilization facilities inside and outside the hydrogen and ammonia production system 1 .

The valuable object production facility 20 produces valuable objects using wastewater (ammonia-containing wastewater) discharged from the facility 10 . Specific examples of the valuable substances produced by the valuable substance production facility 20 include hydrogen and ammonia, and urea and methane can also be produced.

Regarding the valuable substance generation facility 20 shown in FIG. 1 , the first ammonia recovery device 21 is a device that recovers ammonia contained in the exhaust gas treatment wastewater F1 by a gas stripping process to produce a first ammonia concentrated liquid F4. The first pH adjuster supply device 23 is a supply device for an alkaline chemical (for example, sodium hydroxide, etc.) for adjusting the pH inside the first ammonia recovery device 21 . The first ammonia recovery device 21 is provided with a vertically long stripping tower or a plurality of stripping towers connected continuously in series. The stripping towers are separated by, for example, packing materials, trays, or separation tubes. into a multi-section stripping tower. In the first ammonia recovery device 21 in FIG. 1 , one stripping tower is used as an example, and the stripping tower is divided into three stages in the vertical direction using two trays. It is also possible to divide a gas stripping tower into 4 or more sections using 3 or more trays.

In the first ammonia recovery device 21, high-temperature (about 70°C to about 90°C) exhaust gas treatment wastewater F1 is injected from the upper part of the stripping tower. The exhaust gas treatment wastewater F1 gradually descends downward inside the stripping tower while spreading in the form of mist. On the other hand, high-temperature steam is supplied from the lower part of the stripping tower so as to face the descending exhaust gas treatment wastewater F1. This vapor moves upward while diffusing in the form of mist inside the stripping tower. By the gas-liquid contact between the waste gas treatment wastewater F1 and the steam in this way, ammonia in the waste gas treatment wastewater F1 is transferred to the gas phase and recovered. Here, the pH of the exhaust gas treatment wastewater in the first ammonia recovery device is preferably greater than 8 and less than 9.5. When pH is below 8, ammonia stripping becomes difficult. Furthermore, the dissolved amounts of the scale components in the exhaust gas treatment wastewater F1, that is, Ca ²⁺ and Mg ²⁺ , depend on the pH. If the pH exceeds 9.5, the scale components are likely to be precipitated. Since the exhaust gas treatment wastewater F1 contains a large amount of scale components, the first ammonia recovery device 21 intentionally does not raise the pH, but performs gas stripping in a pH range where scale is difficult to precipitate. That is, the ammonia concentration of the exhaust gas treatment wastewater F1 is relatively high, and there is no need to increase the pH excessively in stripping for recovering the required amount of ammonia as an ammonia source mixed with the boiler wastewater F3 as described below. In addition, the exhaust gas treatment wastewater F1 is at a high temperature (about 70°C to about 90°C) and ammonia is easily liberated, so there is no need to let the pH rise to an area where scale is easily generated. Therefore, the amount of alkaline chemical supplied from the first pH adjusting agent supply device 23 can be reduced, and the cost of the chemical can be reduced.

The ammonia and water vapor transferred to the gas phase are discharged from the upper part of the stripping tower and recovered as the first ammonia concentrate F4, and are then put into the second ammonia recovery device 22 together with the boiler wastewater F3. The ammonia concentration of the first ammonia concentrated solution F4 is, for example, about several to 10%. Furthermore, the steam F2 generated in the boiler 16 can be used as the steam supplied from the lower part of the stripping tower, or other steam can be used. Also in the steam F2, if the exhaust steam supplied to the steam turbine 54 is reused, the cost of steam utilization can be reduced.

The second ammonia recovery device 22 is a device that recovers ammonia contained in the boiler wastewater F3 by a stripping process to produce a second ammonia concentrated liquid F8. The second pH adjuster supply device 24 is a supply device for an alkaline chemical (eg, sodium hydroxide, etc.) for adjusting the pH inside the second ammonia recovery device 22 . The second ammonia recovery device 22 is also provided with a stripping tower similar to that of the first ammonia recovery device 21 .

In the second ammonia recovery device 22, the first ammonia concentrated liquid F4 is injected from the upper part of the stripping tower together with the high-temperature (about 70°C to about 90°C) boiler wastewater F3. In this embodiment, a mixed liquid obtained by mixing the first ammonia concentrated liquid F4 and the boiler wastewater F3 in advance is sprayed. The mixed liquid of the boiler drain water F3 and the first ammonia concentrated liquid F4 gradually descends downward inside the stripping tower while spreading in a mist-like form. On the other hand, high-temperature steam is supplied from the lower part of the stripping tower so as to face the descending mixed liquid. This vapor moves upward while diffusing in the form of mist inside the stripping tower. By such gas-liquid contact between the mixed liquid and the vapor, the ammonia in the mixed liquid is transferred to the gas phase and recovered. By putting the first ammonia concentrated liquid F4 containing a high concentration of ammonia and the boiler wastewater F3 containing a relatively low concentration of ammonia into the second ammonia recovery device 22, the ammonia concentration of the boiler wastewater F3 can be increased. In addition, since the boiler drainage water F3 and the first ammonia concentrated solution F4 contain less scale components, the pH can be raised without worrying about scale precipitation. The pH of the mixed liquid here can be adjusted to, for example, 10 to 12 by supplying an alkali agent from the second pH adjuster supply device 24 . At this time, since both the boiler drain water F3 and the first ammonia concentrated liquid have high pH values, the amount of alkali agent supplied from the second pH adjuster supply device 24 is small. Furthermore, the boiler drainage water F3 is at a high temperature (about 70°C to about 90°C), and the first ammonia concentrated liquid F4 is also at a high temperature, so the cost of heating each liquid is small. In this way, the efficiency of recovering ammonia by gas stripping in the second ammonia recovery device 22 can be improved. In addition, the first ammonia concentrated liquid F4 and the boiler wastewater F3 may be separately injected into the second ammonia recovery device 22 and mixed therein, instead of being mixed in advance.

The ammonia and water vapor transferred to the gas phase are discharged from the upper part of the stripping tower and recovered as the second ammonia concentrated liquid F8. The ammonia concentration of the second ammonia concentrated liquid F8 is higher than that of the first ammonia concentrated liquid F4, for example, about 25% to about 50%. The second ammonia concentrated liquid F8 can be supplied as fuel or raw material to the ammonia utilization equipment 41 such as chemical equipment and ammonia gas turbine. Alternatively, the second ammonia concentrated liquid F8 can be supplied to the exhaust gas from the ammonia supply device 12 and used as a denitrification agent (a reducing agent that reduces NOx to nitrogen) or in the production of chemicals. Furthermore, the steam F2 generated in the boiler 16 can be used as the steam supplied from the lower part of the stripping tower, or other steam can be used. Also in the steam F2, if the exhaust steam supplied to the steam turbine 54 is reused, the cost of steam utilization can be reduced.

In the lower part of the stripping tower of the first ammonia recovery device 21, the waste water F5 from which ammonia has been removed is retained. This wastewater F5 is introduced into the coagulation treatment tank 26 . The agglomeration treatment tank 26 is a tank for removing the scale component F7 (for example, Ca ²⁺ , Mg ^{2+ ,} etc.) contained in the waste water F5 . The coagulation treatment tank 26 is provided with a coagulant supply device 25 that supplies a coagulant for coagulating the scale component F7 in the waste water F5. The coagulant supplied from the coagulant supply device 25 may be an inorganic coagulant (such as ferric chloride liquid, etc.) or an organic coagulant (such as a polymer coagulant, etc.). The scale component F7 in the waste water F5 is precipitated in the form of solid matter inside the agglomeration treatment tank 26 and can be easily removed. The aggregated wastewater F6 (supernatant) from the wastewater F5 in which the scale component F7 has been removed is supplied to the integrated wastewater treatment device 40 . It is also possible to directly supply the wastewater F5 to the integrated wastewater treatment facility 40 without providing the aggregation treatment tank 26 .

In the lower part of the stripping tower of the second ammonia recovery device 22, the waste water F9 from which ammonia has been substantially removed is retained. This wastewater F9 is introduced into the ion removal device 27 . The ion removal device 27 is a device that removes alkali components (unnecessary ions) such as ammonia and sodium hydroxide in the waste water F9 remaining after the stripping process. The ion removal device 27 is provided with, for example, an RO membrane (reverse osmosis membrane) and an ion exchange tower filled with an ion exchange resin (for example, a high-temperature ion exchange resin). The RO membrane allows hydrogen ions (H ⁺ ) and hydroxide ions (OH ^- ) in water to pass through and prevents other ions (such as Ca ²⁺ , Mg ²⁺ , NH ₄ ⁺ , etc.) from passing through. Ion exchange resin is a gel-like synthetic resin particle that replaces unnecessary ions in water with hydrogen ions or hydroxide ions. For example, heat-resistant cation exchange resin is used. By utilizing their effects, the waste water F9 is separated into the filtered water F11 from which unnecessary ions have been removed, and the ion concentrate F10 containing the unnecessary ions. The filtered water F11 generated here is supplied to the water electrolysis device 28 . The ion concentrate F10 containing ammonia components and other residual alkali components is supplied to the integrated wastewater treatment device 40 and reused as an alkali source (ammonia source) for organic or inorganic wastewater treatment. Thereby, the residual alkali component contained in the ion concentrate F10 can be used as an ammonia source for wastewater treatment. In other words, the waste water F9 of the second ammonia recovery device 22 can be effectively reused as a resource. In addition, the wastewater F9 is the wastewater after ammonia has been recovered in the second ammonia recovery device, so the amount of chemicals used to recover ammonia is small.

The water electrolysis device 28 is a device that electrolyzes the filtered water F11 generated by the ion removal device 27 to produce hydrogen F12. Generally speaking, water with no impurities or very few impurities, that is, pure water or water substantially equivalent to pure water, is supplied to a water electrolysis device to perform electrolysis. Therefore, the filtered water F11 is pure water or water substantially equivalent to pure water. The hydrogen F12 generated here is supplied as fuel or raw material to hydrogen utilization equipment 42 such as chemical equipment, fuel cells, and hydrogen turbines. Oxygen that may be generated during the electrolysis of the filtered water F11 may be discharged to the atmosphere, supplied to the inside of the combustion chamber 11 as a combustion accelerator, or stored in an oxygen storage tank (not shown). In general, a water electrolysis device is equipped with a heating device for heating pure water at room temperature in order to perform electrolysis efficiently. However, the energy used to heat pure water at room temperature is very large. However, in the water electrolysis device 28 of the embodiment, the energy required for the heating device can be reduced. This is because the raw material of the water electrolysis device 28, that is, the boiler wastewater F3 is high temperature, and the water temperature of the filtered water F9 separated by the ion removal device 27 is also high, so it is easier to adjust to a high temperature than normal temperature.

The integrated wastewater treatment device 40 is a various device that processes facility wastewater F16 including various types of wastewater discharged from the facility, and is, for example, a facility for wastewater treatment including an organic treatment device and an inorganic treatment device. The organic treatment device is a wastewater treatment device equipped with a nitrification tank, a denitrification tank, an aeration tank, etc., and performs biological treatment (drainage treatment based on the action of microorganisms). The inorganic treatment device is a drainage treatment device that performs inorganic water treatment. The organic treatment device is provided with, for example, a nitrifying tank, a denitrifying tank, an aeration tank, etc., and the ammonia in the wastewater is converted into nitrogen by the action of nitrifying bacteria, denitrifying bacteria, etc. and is removed. The inorganic treatment device is provided with, for example, a chemical reaction tank, a sedimentation tank, a filter tank, etc., to chemically remove impurities, metals, etc. in the wastewater. The wastewater treated by the integrated wastewater treatment device 40 can be reused in the equipment 10, the valuable substance generation facility 20, and the integrated wastewater treatment device 40, or can be discharged to the outside.

[B. Function, effect] Generally speaking, the ammonia concentration suitable for gas stripping treatment is about 2000mg/L. However, the ammonia concentration of boiler drainage F3 is relatively low, and most of them are not suitable for gas stripping treatment. For example, assume that the water temperature of boiler drainage F3 is about 80°C, the discharge volume is about 150m ³ /day, and the ammonia concentration is about 600mg/L. The water temperature of exhaust gas treatment drainage F1 is about 80°C, the discharge volume is about 80m ³ /day, and the ammonia concentration is 3000mg. /L. In this case, the discharge amount of the boiler wastewater F3 is large and the concentration of ammonia contained therein is low. Therefore, it is difficult to efficiently recover ammonia by performing a stripping process using only the boiler wastewater F3.

On the other hand, in the hydrogen and ammonia production system 1 described above, first, the exhaust gas treatment wastewater F1 is subjected to a stripping process in the first ammonia recovery device 21 to recover ammonia. At this time, even if the pH of the waste gas treatment wastewater F1 is about 9, free ammonia can be reduced to about 90% at a high temperature of about 80°C. If all the free ammonia is recovered, the first ammonia with an ammonia concentration of about 54000 mg/L can be About 4m ³ of concentrated liquid F4 is recovered. The recovered first ammonia concentrated liquid F4 is put into the second ammonia recovery device 22 together with the boiler wastewater F3, and is again stripped.

Here, the ammonia concentration of the mixed liquid of the boiler wastewater F3 and the first ammonia concentrated liquid F4 is about 2000 mg/L, and an ammonia concentration suitable for the gas stripping treatment is obtained. Therefore, the ammonia stripping efficiency in the second ammonia recovery device 22 is improved. In addition, by adjusting the pH of the mixed liquid and performing a stripping process in the second ammonia recovery device 22, an ammonia solution with a concentration of 25% in the market can be easily obtained as the second ammonia concentrated liquid F8.

At this time, the ammonia concentration remaining in the waste water F9 discharged from the second ammonia recovery device 22 becomes approximately 200 mg/L. By supplying this wastewater F9 to the ion removal device 27 and concentrating it using a high-temperature ion exchange resin, an ion concentrate F10 and filtered water F11 in which the remaining alkali components are concentrated can be obtained. The volume of the ion concentrate F10 obtained here was approximately 6 m ³ , and the concentration of the residual alkali component was approximately 5000 mg/L. If the concentration of the residual alkali component is converted into ammonia nitrogen, it can be used as an alkali source (ammonia source) for organic wastewater treatment of approximately 200 m ³ per day, and is suitable for maintaining bacterial cells in organic biological treatment.

In the above hydrogen and ammonia production system 1, the first ammonia concentrated liquid F4 is produced in the first ammonia recovery device 21 from the exhaust gas treatment wastewater F1, and the first ammonia concentrated liquid F4 and the boiler wastewater F3 are put into the second ammonia recovery device 22. To produce the second ammonia concentrated liquid F8, ammonia can be recovered efficiently compared to performing a stripping process by separately combining the exhaust gas treatment wastewater F1 and the boiler wastewater F3 or by mixing the exhaust gas treatment wastewater F1 and the boiler wastewater F3. It is not necessary to use a large amount of chemicals to capture the ammonia contained in the boiler wastewater F3 by pre-treatment, or to use a large amount of chemicals to adjust the pH of the exhaust gas treatment wastewater F1 to remove scale, as in the technologies of Patent Document 1 and Patent Document 2. After the components are removed and the pH is adjusted again, ammonia can be easily recovered. Therefore, according to the hydrogen and ammonia production system 1 described above, the wastewater from the facility 10 can be reused for the production of valuable substances (eg, hydrogen, ammonia) and chemicals, and valuable substances can be efficiently and cheaply produced from the wastewater from the facility 10 .

[2. First modification] FIG. 2 is a block diagram showing the structure of the hydrogen and ammonia production system 1' according to the first modification. The same reference numerals are assigned to the same components as those described in the embodiments, and descriptions of the components and effects will be appropriately omitted. The hydrogen and ammonia production system 1' includes a valuable substance generation facility 20' that supplies a part of the first ammonia concentrated liquid F4 to the first ammonia recovery device 22 at a different position from the boiler wastewater F3. The second flow path causes the first ammonia concentrated solution F4 to flow to the second flow path when the ratio of the ammonia amount between the boiler wastewater F3 and the first ammonia concentrated solution F4 in the first flow path is greater than a certain value.

The valuable substance generation facility 20' is provided with a first flow path 60 for mixing the first ammonia concentrated liquid F4 and the boiler wastewater F3, and branches from the first flow path 60 to supply the first ammonia concentrated liquid F4 to the first ammonia recovery device. 22 second flow path 61, a control valve 62 that adjusts the flow rate of the first ammonia concentrated liquid F4 flowing through the second flow path 61, a control device 63 that controls the control valve 62, and an ammonia concentration meter that measures the ammonia concentration of the boiler wastewater F3 64. A flow meter 65 that measures the flow rate of the boiler drainage F3, an ammonia concentration meter 66 that measures the ammonia concentration of the first ammonia concentrate F4 in the first flow path 60, and a flow meter 66 that measures the first ammonia concentrate in the first flow path 60 F4 flow meter 67. The control device 63 calculates the ammonia amount ratio of the first ammonia concentrated liquid F4 relative to the boiler drainage water F3 based on the ammonia concentration and flow rate values measured by the ammonia concentration meter and the flow meter of each liquid. When the ammonia amount ratio becomes If the predetermined value, for example, is 2 or more, it is deemed that a sufficient amount of ammonia is supplied to the boiler drainage F3, and the adjustment valve 62 is opened to supply a predetermined amount to the second flow path 61 such that the ammonia amount ratio does not fall below the predetermined value. For example, the first ammonia concentrated liquid F4 is about 1/10 of the first flow path. For example, a pH meter may be provided instead of the ammonia concentration meter, and the ammonia concentration may be determined based on the measured pH value. In addition, in the vertical direction of the second ammonia recovery device 22, the position where the mixed liquid of the boiler drainage F3 mixed with the first ammonia concentrated liquid F4 is supplied is called a third position P3, and flows through the second flow path The position in the vertical direction where the first ammonia concentrate F4 of 61 is supplied to the second ammonia recovery device 22 is called the fourth position P4. The fourth position P4 is preferably set at a different position from the third position P3, and more preferably The fourth position P4 is set above the third position P3. In FIG. 2 , in the second ammonia recovery device 22 whose interior is divided into three sections, the fourth position P4 is arranged in a section above the third position P3. In addition, the first ammonia concentrated liquid F4 in the first flow path may not be mixed with the boiler drain water F3 in advance, but may be supplied to a position in the second ammonia recovery device 22 where it is mixed with the boiler drain water F3. For example, it may be supplied from the vicinity of the third position P3. The first ammonia concentrate is supplied to be mixed with boiler drainage F3.

By making the third position P3 and the fourth position P4 different from each other, the mist-like liquid to be treated supplied from the respective locations can be easily diffused uniformly inside the stripping tower, thereby improving the gasification efficiency of ammonia. Furthermore, by setting the fourth position P4 higher than the third position P3, it is easy to ensure the time and distance required for ammonia to vaporize from the first ammonia concentrated liquid F4 supplied to the second ammonia recovery device 22. Further improve ammonia gasification efficiency. Therefore, the concentration of ammonia in the second ammonia recovery device 22 can be promoted.

[3. Second modification] FIG. 3 is a block diagram showing the structure of the hydrogen and ammonia production system 1″ according to the second modification. The same structures as those described in the embodiment are given the same reference numerals, and descriptions of the structures and effects are appropriately omitted. The hydrogen and ammonia production system 1″ includes a valuable substance generation facility 20″ that circulates a part of the first ammonia concentrated liquid F4 and a part of the second ammonia concentrated liquid F8 to the first ammonia recovery device 21, respectively. and the second ammonia recovery device 22.

In the valuable substance generation facility 20″, a part of the first ammonia concentrated liquid F4 passes through the first circulation path 31 and is again put into the first ammonia recovery device 21. Similarly, a part of the second ammonia concentrated liquid F8 passes through the second circulation The second ammonia recovery device 22 is again put into the path 32. In this way, by circulating a part of the first ammonia concentrated liquid F4 and the second ammonia concentrated liquid F8, the ammonia concentration contained in these concentrated liquids can be further increased. In conjunction with the change in flow rate of boiler drainage F3, a more concentrated second ammonia concentrate F8 can be obtained.

Here, the position in the vertical direction where the exhaust gas treatment wastewater F1 is supplied to the first ammonia recovery device 21 is called the first position P1, and the position in the vertical direction where the first ammonia concentrated liquid F4 is reintroduced from the first circulation path 31 is called the first position P1. is the second position P2. The second position P2 may be set at the same position as the first position P1, but is preferably set at a different position from the first position P1. More preferably, the second position P2 is set higher than the first position P1. In FIG. 3 , in the ammonia recovery device 21 whose interior is divided into three sections, the second position P2 is arranged in the uppermost section, and the first position P1 is arranged in the section below the second position P2. As long as they are at different positions in the vertical direction, the same effect can be obtained even if they are placed in the same section.

By making the first position P1 and the second position P2 different from each other, the mist-like liquid to be treated supplied from the respective locations can be easily diffused uniformly inside the stripping tower, thereby improving the gasification efficiency of ammonia. It can also suppress the increase in pH of the exhaust gas treatment wastewater F1 caused by the mixing of the exhaust gas treatment wastewater F1 and the first ammonia concentrated solution F4, thereby inhibiting the precipitation of scale components. Furthermore, by setting the second position P2 above the first position P1, it is easy to ensure the time and distance required for the ammonia to vaporize from the first ammonia concentrated liquid F4 that is reintroduced into the first ammonia recovery device 21, and further can be achieved. Improve ammonia gasification efficiency. Therefore, the concentration of ammonia in the first ammonia recovery device 21 can be promoted.

Similarly, the position in the vertical direction where the second ammonia concentrated liquid F8 is reintroduced from the second circulation path 32 is called the fifth position P5. The fifth position P5 may be set at the same position as the third position P3 and the fourth position P4, but is preferably set at a different position from the third position P3 and the fourth position P4. More preferably, the fifth position P5 is set above the third position P3 and the fourth position P4.

By making the third position P3, the fourth position P4, and the fifth position P5 different from each other, the mist-like treated liquid supplied from the respective locations can be easily spread evenly inside the stripping tower, thereby improving the vaporization of ammonia. efficiency. Furthermore, by setting the fifth position P5 higher than the third position P3 and the fourth position P4, it is easy to ensure the required amount of gasification of ammonia from the second ammonia concentrated liquid F8 that is reintroduced into the second ammonia recovery device 22. Time and distance can further improve the gasification efficiency of ammonia. Therefore, the concentration of ammonia in the second ammonia recovery device 22 can be promoted. Therefore, according to the hydrogen and ammonia production system 1″, the waste water from the facility 10 can be reused for the production of valuable substances (for example, hydrogen, ammonia) and chemicals, and valuable substances can be efficiently and cheaply generated from the waste water from the facility 10.

[4. Third modification] FIG. 4 is a block diagram showing the structure of the hydrogen and ammonia production system 1''' according to the third modification. The same structures as those explained in the embodiment and the first modification are given the same reference numerals, and the structures and effects are The description is appropriately omitted. The hydrogen and ammonia production system 1″′ of the third modification is applied to the equipment 10″′ provided with the carbon dioxide separation device 18, and includes valuable substance production including a urea production device 33 and a methanation device 34. Facilities 20″′.

The carbon dioxide separation device 18 is a device for recovering carbon dioxide F13 contained in the exhaust gas. As a method for recovering carbon dioxide F13, various known methods can be used. For example, carbon dioxide F13 can be recovered from exhaust gas using a polymer separation membrane (carbon dioxide separation membrane). Alternatively, a medium with high absorption and adsorption properties for carbon dioxide F13 can be brought into contact with the exhaust gas for recovery. When solid media is used, activated carbon and zeolite can be used to adsorb carbon dioxide F13 in the exhaust gas, and the carbon dioxide F13 can be recovered by heating and depressurizing. When using a liquid medium, amine solution, potassium carbonate aqueous solution, ammonia solution, etc. can be used to adsorb carbon dioxide F13 for recovery.

By using the recovered carbon dioxide F13 and the hydrogen F12 and ammonia concentrate F8 produced in the hydrogen and ammonia production system 1, it can be utilized for various purposes. In FIG. 3 , the recovered carbon dioxide F13 and the ammonia concentrate F8 can be supplied to the urea production device 33 , and the recovered carbon dioxide F13 and hydrogen F12 can be supplied to the methanation device 34 . The urea production device 33 is a device that synthesizes the carbon dioxide F13 and the second ammonia concentrate F8 to produce urea F14 (CH ₄ N ₂ O). The urea production device 33 is provided with a reactor (catalyst-free container) for maintaining a high-temperature and high-pressure state, and generates urea F14 inside the reactor. The urea F14 generated here is supplied to the urea utilization equipment 43 . The urea utilization equipment 43 includes, for example, chemical equipment, a plant factory using urea F14 as fertilizer, and the like.

The methanation device 34 is a device that synthesizes carbon dioxide F13 and hydrogen F12 to generate methane F15 (CH ₄ ). Here, methane F15 is synthesized, for example, by methanation reaction through co-electrolysis reaction or Sabatier reaction. The methanation device 34 is provided with a reactor (catalyst container) containing a catalyst for methane synthesis, and methane F15 is generated inside the reactor. The methane F15 generated here is supplied to the methane gas utilization equipment 44 . The methane gas utilization equipment 44 includes, for example, buildings and equipment (gas pipes) that use methane F15 as fuel (urban gas), a gas engine that burns methane F15 to generate electricity, and the like.

As described above, by installing the carbon dioxide separation device 18 in the equipment 10″′, carbon dioxide F13 in the exhaust gas can be removed, and the amount of carbon dioxide F13 discharged from the chimney 15 can be significantly reduced. In addition, by installing the valuable matter generation facility 20 ″′ By providing the urea production device 33, urea F14 can be easily produced using the carbon dioxide F13 and the second ammonia concentrate F8 produced in the valuable substance production facility 20″. Furthermore, by using the valuable substance production facility 20″ ' By providing the methanation device 34, methane F15 can be easily generated using the carbon dioxide F13 and the hydrogen F12 produced in the valuable substance generation facility. Therefore, according to the hydrogen and ammonia production system 1″′, the drainage water from the equipment 10″′ can be reused for the production of valuable substances (such as hydrogen, ammonia, urea, methane) and chemicals. Generate something of value efficiently and cheaply.

1,1′,1″:Hydrogen and ammonia production system 10,10″,10″′:Equipment 11: Combustion chamber (combustion furnace) 12: Ammonia supply device 13:Dust collection device 14: Wet treatment device 15: Chimney 16: Boiler 18:Carbon dioxide separation device 19:Exhaust gas treatment device 20, 20′, 20″, 20″′: valuable generation facilities 21: The first ammonia recovery unit 22: The second ammonia recovery unit 23: The first pH adjuster supply device 24: Second pH adjuster supply device 25: Coagulant supply device 26: Agglutination treatment tank 27:Ion removal device 28:Water electrolysis device 31: 1st Circular Road (Circular Road) 32: 2nd Circular Road 33: Urea manufacturing equipment 34:Methanation unit 40: Comprehensive drainage treatment device 41: Ammonia utilization equipment 42:Hydrogen utilization equipment 43: Urea utilization equipment 44: Methane gas utilization equipment 50:Pure water production device 51: Additive supply device 52:Steam drum 53:Heat recovery device 54:Steam turbine 55:Generator 56:Rehydrator 57:Degasser 60: 1st flow path 61: 2nd flow path 62:Control valve 63:Control device 64: Ammonia concentration meter 65:Flow meter 66: Ammonia concentration meter 67:Flow meter F1: Waste gas treatment and drainage F2: steam F3: Boiler drainage F4: The first ammonia concentrate F5: Drainage F6: Coagulation drainage F7: Scale ingredients F8: The second ammonia concentrate F9: Drainage F10: Ion concentrate F11: filtered water F12:Hydrogen F13: carbon dioxide F14: Urea F15: Methane F16: Equipment drainage P1: No. 1 position P2: 2nd position P3: 3rd position P4: 4th position P5: 5th position

[Fig. 1] is a block diagram showing an embodiment of the present invention. [Fig. 2] is a block diagram showing the first modification of the present invention. [Fig. 3] is a block diagram showing a second modification of the present invention. [Fig. 4] is a block diagram showing a second modification of the present invention.

1: Hydrogen and ammonia production system

10:Equipment

11: Combustion chamber (combustion furnace)

12: Ammonia supply device

13:Dust collection device

14: Wet treatment device

15: Chimney

16: Boiler

19:Exhaust gas treatment device

20:Value generation facility

21: The first ammonia recovery unit

22: The second ammonia recovery device

23: The first pH adjuster supply device

24: Second pH adjuster supply device

25: Coagulant supply device

26: Agglutination treatment tank

27:Ion removal device

28:Water electrolysis device

40: Comprehensive drainage treatment device

41: Ammonia utilization equipment

42:Hydrogen utilization equipment

50:Pure water production device

51: Additive supply device

52:Steam drum

53:Heat recovery device

54:Steam turbine

55:Generator

56:Rehydrator

57:Degasser

F1: Waste gas treatment and drainage

F2: steam

F3: Boiler drainage

F4: The first ammonia concentrate

F5: Drainage

F6: Coagulation drainage

F7: Scale ingredients

F8: The second ammonia concentrate

F9: Drainage

F10: Ion concentrate

F11: filtered water

F12:Hydrogen

F16: Equipment drainage

Claims (5)

A hydrogen and ammonia production system, which is equipped with a first ammonia recovery device, a second ammonia recovery device, an ion removal device, a water electrolysis device, and organic or inorganic wastewater treatment of the aforementioned equipment in a facility equipped with a boiler and an exhaust gas treatment device. device, The aforementioned boiler uses the heat of the combustion furnace or combustion chamber to generate steam and discharge boiler water. The aforementioned exhaust gas treatment device processes the exhaust gas generated from the aforementioned combustion furnace or the aforementioned combustion chamber and discharges the exhaust gas treatment wastewater, The above-mentioned first ammonia recovery device performs a stripping process on the above-mentioned exhaust gas treatment wastewater to recover ammonia and produce a first ammonia concentrated liquid, The second ammonia recovery device performs a stripping process on the first ammonia concentrate and the boiler wastewater to recover ammonia and produce a second ammonia concentrate, The ion removal device is configured to pass the boiler wastewater discharged from the second ammonia recovery device and separate it into filtered water and an ion concentrate containing residual alkali components, The aforementioned water electrolysis device electrolyzes the aforementioned filtered water to produce hydrogen, The organic or inorganic wastewater treatment device of the above-mentioned equipment is input using the above-mentioned ion concentrated liquid as an alkali source. The hydrogen and ammonia production system described in claim 1, which has a first flow path and a second flow path, The aforementioned first flow path allows the aforementioned first ammonia concentrated liquid to flow through, The second flow path, when the ratio of the ammonia amount of the ammonia concentrate in the first flow path to the ammonia amount of the boiler wastewater is more than a predetermined value, allows the flow of water not less than the predetermined value from the first flow path. The first degree of ammonia concentrated liquid flows through, The aforementioned boiler drainage system is supplied to the third position of the aforementioned second ammonia recovery device, The first ammonia concentrated liquid in the second flow path is supplied to a fourth position different from the third position in the vertical direction of the second ammonia recovery device. The hydrogen and ammonia production system according to Claim 2, which is provided with a first circulation path for circulating a part of the first ammonia concentrated liquid to the first ammonia recovery device, The aforementioned exhaust gas treatment drainage system is supplied to the first position of the aforementioned first ammonia recovery device, The first ammonia concentrated liquid passing through the first circulation path is supplied to a second position of the first ammonia recovery device that is different from the first position. The hydrogen and ammonia production system according to claim 3, which is provided with a second circulation path for circulating a part of the second ammonia concentrated liquid to the second ammonia recovery device, The second ammonia concentrated liquid passing through the second circulation path is supplied to a fifth position in the vertical direction of the second ammonia recovery device that is different from the third position. The hydrogen and ammonia production system described in any one of claims 1 to 4, which is equipped with a carbon dioxide separation device, a methanation device and/or a urea production device, The carbon dioxide separation device separates carbon dioxide from the exhaust gas discharged from the exhaust gas treatment device, The methanation device produces methane gas from the carbon dioxide and the hydrogen separated by the carbon dioxide separation device, The urea production device produces urea from the carbon dioxide and the second ammonia concentrate separated by the carbon dioxide separation device.

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