JP2003020221A - Aqueous ammonia manufacturing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus having excellent mobility and for efficiently manufacturing aqueous ammonia. SOLUTION: The apparatus for manufacturing aqueous ammonia has a reactor cooled to have a fixed reaction temperature by automatic control, a water absorption type ammonia separator in which water is automatically supplied to have a fixed water level and which is automatically cooled to have a fixed temperature of the aqueous ammonia, a dehumidifier and a gas pressure elevating apparatus, which are arranged in a circulation line automatically controlled to have a fixed flow rate, and has a mechanism for supplying hydrogen and nitrogen as raw material by automatic control to have a fixed pressure of the circulation line. The ammonia gaseous starting materials and an ammonia synthetic gas are controlled to keep reaction equilibrium in reactor, and an ammonia-containing gas and the aqueous ammonia are controlled to keep gas- liquid equilibrium in the water absorption type ammonia separator. Water, hydrogen and nitrogen are supplied by automatic control correspondingly to the demand of ammonia water to automatically control the reaction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for producing ammonia water used for flue gas denitration and the like.

[0002]

2. Description of the Related Art Ammonia is a chemical product used in a wide range of applications such as industry, agriculture and medicine. Therefore, the ammonia production facility is a large-scale device for producing high-purity products assuming various uses. In a normal ammonia production facility, ammonia is synthesized using hydrogen and nitrogen as raw materials and an iron-based catalyst. The reaction conditions of the iron-based catalyst are 400 ° C. to 600 ° C. and 10 to 50 MPaG at which the activity of this catalyst becomes high.
High temperature and high pressure. The synthesized ammonia is collected as a liquid solution by the cryogenic separation method. Ammonia water is usually produced by absorbing the ammonia produced from such equipment into water.

As a method for producing this ammonia, a synthesis gas mainly composed of hydrogen and nitrogen is circulated between an ammonia synthesis reaction tower and a wet recovery tower for the produced ammonia, and the ammonia produced in the reaction tower is continuously fed in the recovery tower. In wet recovery, the raw material gas for synthesis consisting of crude hydrogen and nitrogen is injected into the circulating gas between the reaction tower outlet and the recovery tower inlet, and impurities such as catalyst poison components derived from the crude hydrogen are wet-collected in the wet recovery tower. There is known a method for producing an aqueous ammonia solution, which is characterized in that it is recovered and removed as an ammonium salt (JP-A-200).
0-44230).

As an example of utilizing this ammonia, it is mainly used as a reducing agent in flue gas denitration for removing nitrogen oxides (NOx) emitted from fixed sources such as thermal power plants for business use, cogeneration power generation, and refuse incinerators. Ammonia is used for.

This ammonia is usually transported from the ammonia production plant to a storage facility in the vicinity of the flue gas denitration device by a truck or tanker and temporarily stored. Immediately before use, ammonia is vaporized, diluted with air to about 1 to 10%, and sprayed in the exhaust gas. On the other hand, when using ammonia water, usually, ammonia water (25%, etc.) is transported from the ammonia water production plant to a storage facility near the flue gas denitration device by a truck or tanker and temporarily stored, and in some cases vaporized. After doing
It is sprayed in the exhaust gas.

[0006]

In the conventional method, transportation and storage of the reducing agent becomes a problem when performing flue gas denitration. In particular, ammonia is a highly toxic, explosive and flammable substance, and is dangerous.
Cost is needed. Further, it is difficult to load ammonia required for one voyage on a narrow ship at a mobile generation source such as a ship. Therefore, very few ships are equipped with a denitration device, and a large amount of NOx is emitted. Moreover, the conventional ammonia production equipment is an equipment for mass-producing high-purity ammonia. The reaction conditions are high temperature and high pressure, the number of equipment is large, and the operation is complicated and difficult. However, it is difficult to produce ammonia.

The present invention is not limited to flue gas denitration, but was made to solve the above-mentioned problems in flue gas denitration as an effective use, and is highly mobile. It is an object of the present invention to provide an apparatus capable of efficiently producing aqueous ammonia under mild reaction conditions.

[0008]

[Means for Solving the Problems] The above problems are as follows: a reactor that is automatically controlled to keep a constant reaction temperature; water is automatically controlled to keep a constant liquid level; Water absorption type ammonia separator, which is cooled by automatic control so as to be constant, a dehumidifier, and a gas pressure booster,
The reactor is arranged in a circulation line that is automatically controlled so that the circulation flow rate is constant, and has a mechanism that automatically supplies hydrogen and nitrogen that are raw materials so that the pressure in the circulation line is constant. The reaction equilibrium between the ammonia raw material gas and the ammonia synthesis gas is used inside, and the gas-liquid equilibrium between the ammonia-containing gas and the ammonia water is used inside the water absorption type ammonia separator. The problem can be solved by an ammonia water production device that can supply nitrogen by automatic control and automatically control the reaction amount.

Further, the above object can be more preferably achieved by filling the reactor with a ruthenium catalyst and using it.

The device of the present invention has the following features. Since it is a simple device and easy to operate, it can be installed on the spot where there is a demand for ammonia such as NOx fixed source and NOx removal device for mobile source (transportation of liquid ammonia or ammonia water). , It reduces costs and risks because it does not require storage). Since it is possible to produce ammonia water with a concentration and purity suitable for the concentration of spray to the denitration device, no dilution is required (no dilution device is required). The demand amount of ammonia changes momentarily with respect to the NOx load in the exhaust gas, but since it can respond with good follow-up, there is no frequent start / stop of the device, and there is no need to make it in advance or only a small amount. Depending on the choice of hydrogen production equipment, it is possible to use only water, air and electricity as raw materials, and it is easy to obtain, clean, and does not require complicated equipment. Further, by filling the reactor with the ruthenium catalyst, it is possible to operate under mild conditions.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <Description of Process> FIG. 1 shows a schematic flow. Nitrogen obtained by an air separation method such as PSA or cryogenic separation or a membrane, and hydrogen obtained by electrolysis of water or steam reforming of hydrocarbons are supplied to a circulation line. The supply amounts of nitrogen and hydrogen are determined such that a pressure indicating controller is installed in the circulation line and the pressure in the circulation line becomes constant at a predetermined pressure. The pressure of this circulation line is about 1 to 50 MPa, usually 10 to 40 MPa
When the Ru-based catalyst is used as the ammonia synthesis catalyst, the pressure is about 0.1 to 10 MPa, usually about 0.5 to 3 MPa.

The supply ratio of nitrogen to hydrogen is basically 1: 3 of the stoichiometric ratio. In addition, the partial pressure ratio of nitrogen and hydrogen in the circulating gas depends on the catalyst used, operating conditions, equipment costs,
There is an optimum value determined from utility costs, etc., and the device is operated to reach this optimum value, but the partial pressure ratio gradually changes due to the difference in the solubility of hydrogen and nitrogen in ammonium hydroxide in the ammonia separator. Resulting in. Therefore, the supply ratio of nitrogen and hydrogen is determined so that a gas concentration indicator controller is installed in the circulation line so that the gas component in the circulation line becomes constant at a predetermined partial pressure ratio.

As a concrete method of this, as shown in FIG. 6, a flow rate indicating controller + control valve is installed in each of the hydrogen and nitrogen supply lines, and a signal from the pressure indicating controller in the circulation line is used. It is transmitted to and controlled by the flow rate indicating controller + control valve of that raw material supply line, and the signal from this flow rate indicating controller is sent to the flow rate indicating controller of the other raw material supply line via the ratio setting device. It will be transmitted and controlled later. The ratio in the ratio setter is calculated and determined by the signal from the gas concentration indicating controller of the circulation line.

Alternatively, as shown in FIG. 7, a flow rate indicating controller + control valve is installed in each of the hydrogen and nitrogen supply lines, and a signal from the pressure indicating controller in the circulation line is supplied to either raw material. It is transmitted to and controlled by the flow rate indicator controller + control valve of the line, and the signal from the pressure indicator controller of the circulation line is passed through the ratio setting device and then the flow rate indicator controller + control of the other raw material supply line. It is transmitted to the valve and controlled. The ratio in the ratio setter is calculated and determined by the signal from the gas concentration indicating controller of the circulation line.

Alternatively, as shown in FIG. 8, a flow rate indicating controller + control valve is installed in each of the hydrogen and nitrogen supply lines, and both the pressure indicating controller and the gas concentration indicating controller in the circulation line are provided. After passing the signal through the ratio setter,
It is controlled by transmitting it to the flow rate indicator controller + control valve of each raw material supply line.

Alternatively, as shown in FIG. 9, a flow rate indicating controller and a controlling valve (A) are respectively connected to the hydrogen and nitrogen supply lines.
And the control valve (B) are installed, and the signal from the pressure indicating controller of the circulation line is transmitted to the flow rate indicating controller + control valve (A) of one of the feed lines of the raw materials to control the flow rate. The signal from the meter is transmitted to and controlled by the flow rate indicator controller + control valve (A) of the other raw material supply line after passing through the ratio setting device. For the ratio setting with the ratio setting device, the expected ratio is entered in advance. However, in this case, the partial pressure ratio in the circulation line gradually changes due to fluctuations in the operating state, so the signal from the gas concentration indicating controller is transmitted to each control valve (B) and excessive in the circulation line. For the raw material, the control valve (B) is closed until the predetermined concentration ratio is reached, and the raw material is not supplied.

Alternatively, as shown in FIG. 10, the flow rate control controller + control valve (A) and control valve (B) are installed in the hydrogen and nitrogen supply lines respectively, and the pressure control controller from the circulation line is operated. The signal is transmitted to and controlled by the flow rate indicator controller + control valve (A) of one of the raw material supply lines, and the signal from the pressure indicator controller of the circulation line is sent to the ratio setting device, and then the other one. It is transmitted to and controlled by the flow rate indicator controller + control valve (A) of the raw material supply line. For the ratio setting with the ratio setting device, the expected ratio is entered in advance. However, in this case, the partial pressure ratio in the circulation line gradually changes due to fluctuations in the operating state, so the signal from the gas concentration indicating controller is transmitted to each control valve (B),
For the excess raw material in the circulation line, the control valve (B) is closed until the concentration ratio reaches a predetermined value, and the raw material is not supplied.

Alternatively, as shown in FIG. 11, the flow rate control controller + control valve (A) and control valve (B) are installed in the hydrogen and nitrogen supply lines, respectively, and the After passing through the ratio setting device, the signal is transmitted to the flow rate indicator controller + control valve (A) of each raw material supply line for control. For the ratio setting with the ratio setting device, the expected ratio is entered in advance. However, in this case, the partial pressure ratio in the circulation line gradually changes due to fluctuations in the operating state, so the signal from the gas concentration indicating controller is transmitted to each control valve (B) and excessive in the circulation line. For the raw material, the control valve (B) is closed until the predetermined concentration ratio is reached, and the raw material is not supplied.

The respective signals are also transmitted to the respective raw material producing devices, for example, controlling the energization amount of the water electrolysis device or controlling the supply amount of the primary raw material such as the supply amount of hydrocarbons or air. May be. Alternatively, the raw material production apparatus should always be operated at a constant production amount, and the overproduced raw material may be used for other purposes such as air emission or power generation by a fuel cell,
The supply amount to the circulation line may be controlled by burning in flare. When the outlet pressure of the raw material production device is lower than the circulating gas pressure, a raw material gas booster is installed.

The circulating gas, to which the raw materials nitrogen and hydrogen are supplied by such a method, is pressurized to a predetermined pressure by the compressor and is controlled by the rotation speed control and spillback of the compressor so that the flow rate becomes a predetermined flow rate. This pressure is 1
˜50 MPa, usually about 10-40 MPa, when the Ru-based catalyst is used as the ammonia synthesis catalyst,
It is about 10 MPa, usually about 0.5 to 3 MPa. Then, the circulating gas is heated to a predetermined temperature and introduced into the reactor. This temperature is about 200 to 600 ° C., usually 400
˜550 ° C., when a Ru-based catalyst is used as the ammonia synthesis catalyst, about 200-500 ° C., usually 350-4
It is about 50 ° C. It is efficient to install a heat exchanger for the circulating gas, which heats up using the heat of the reactor outlet gas before introducing it into the reactor. The ammonia synthesis catalyst is filled in the reactor, and the following ammonia synthesis reaction is performed. The temperature of this synthesis reaction is about 300 to 600 ° C, usually about 400 to 550 ° C, and about 300 to 500 ° C when a Ru-based catalyst is used as the ammonia synthesis catalyst,
It is usually about 350 to 420 ° C. Pressure is 1-50M
Pa, usually 10 to 40 MPa, and 0.1 to 10 MP when a Ru-based catalyst is used as the ammonia synthesis catalyst.
It is about a, usually about 0.5 to 3 MPa. SV (space velocity) is about 1,000～30,000H ^-1, usually about 3,000~15,000h ^-1. When a Ru-based catalyst is used as the ammonia synthesis catalyst, it is less likely to be deactivated by the water content in the gas, so that the dehumidifier described later becomes unnecessary, or a simple device can be used. 1
/ 2N ₂ + 3 / 2H ₂ → NH ₃

Since this reaction is an exothermic reaction, some temperature indicating controllers are installed in the catalyst layer inside the reactor to control the flow rates of water, steam, air, refrigerant, circulating gas, etc. from the outside. It is advisable to control the catalyst temperature so that it is always at a predetermined temperature, for example, by cooling it or by controlling the flow rate of the circulating gas before raising the temperature and introducing it into the reactor.

The gas at the outlet of the reactor is cooled by exchanging heat with the gas at the inlet of the reactor, and further cooled to a predetermined temperature with steam, water, air, refrigerant, etc. from the outside, and introduced into the ammonia separator. To do. The ammonia separator is a gas absorption device such as a packed column or a bubble column. A liquid level indicator controller is installed in the ammonia separator, and the amount of water supplied is controlled so that the liquid level is constant. Further, a temperature indicating controller is installed and controlled by the cooling device so that the liquid temperature becomes constant. The ammonia in the circulating gas after the reaction is absorbed by the ammonia water in the ammonia separator and is not absorbed (hydrogen + nitrogen + (trace amount) ammonia +
Inert substances such as argon) and vapor pressure steam exits the ammonia separator. The ammonia water of the product is extracted from the nozzle provided in the ammonia separator.

The circulating gas discharged from the ammonia separator is dehumidified by a cooling type or adsorption type dehumidifier, is circulated to a raw material supply section of a circulation line, and is introduced again into the reactor after the raw material is supplied. In addition, if a pressure indicating controller and a control valve are installed at the outlet of the ammonia separator to reduce pressure fluctuation on the separator side,
The overall control is stable.

The raw material hydrogen gas and nitrogen gas usually contain inert substances such as argon and methane. These inert gases are accumulated in the circulation line, except for being dissolved in the product ammonia water and discharged out of the circulation line system. As described above, the total pressure of the circulation line is constantly controlled to a predetermined pressure by the pressure indicating controller installed in the circulation line, so the inert gas accumulates in the circulation line and the partial pressure of the inert gas is high. Then, the partial pressures of hydrogen and nitrogen in the circulation line decrease. The lower partial pressures of hydrogen and nitrogen reduce the efficiency of ammonia synthesis in the reactor. Therefore, it is advisable to provide a mechanism for purging the circulation line so that the inert substance does not accumulate above a predetermined concentration. The purge line should be installed at the outlet of the separator. Further, if this mechanism is a mechanism for automatically purging the circulating gas so that the concentration of the inert substance in the circulation line is constant, it is possible to eliminate or reduce the variation in the concentration of the product ammonia water. Regarding the concentration of inert substances in the circulation line, the optimum point required from the purity / price of raw material gas, catalyst performance, equipment shape of reactors, temperature / pressure / flow rate conditions of circulation line, utility cost, construction cost, etc. Exists, and the circulating gas is purged by automatic control so that the optimum point becomes constant. This concentration is about 40% or less, usually about 20% or less, depending on the conditions.

The temperature, pressure, flow rate, liquid level of the device of the present invention
The actual operating value of the item to be automatically controlled, such as the concentration, is controlled to be within ± 50%, usually within ± 20% of the target set value.

<Operating Method> The ammonia water producing apparatus of the process assembled by the above equipment and control method can be operated as follows.

When the ammonia water is extracted from the ammonia separator, water is supplied so that the liquid surface of the ammonia separator is kept constant, and the concentration of the ammonia water in the separator is slightly reduced (product ammonia water). The amount of ammonia water in the separator is designed in consideration of the amount used so that the change in concentration is within the allowable range). As a result, the ammonia in the ammonia synthesis gas is absorbed by the ammonia water so as to return to the gas-liquid equilibrium state of the ammonia gas-ammonia water. This slightly reduces the ammonia concentration and pressure of the separator outlet gas. When the pressure decreases, the pressure indicating controller installed in the circulating gas line detects this and the raw material gas is introduced so as to keep it constant.

The circulating gas whose ammonia concentration is further lowered by the introduction of the raw material gas is introduced into the reactor and the ammonia synthesis reaction is carried out. Also in the ammonia synthesis, there is a reaction equilibrium according to temperature and pressure, and when the ammonia concentration becomes lower than the equilibrium concentration at the reactor inlet,
A synthetic reaction takes place in the reactor and attempts to approach the equilibrium concentration. When the ammonia concentration in the reactor inlet gas is close to equilibrium, the reaction amount becomes small, and when it largely deviates from equilibrium, the reaction amount increases (this mechanism controls the reaction amount). The circulating gas leaving the reactor is reintroduced into the separator.

On the contrary, when the ammonia water is not extracted from the ammonia separator, the ammonia concentration in the ammonia water and the circulating gas is in a vapor-liquid equilibrium state at the temperature and pressure in the separator, and the separator is separated. The concentration of the circulating gas is the same at the inlet and the outlet. Therefore, the pressure detected by the pressure indicating controller is also the same as the predetermined set value, and the raw material gas is not supplied. Therefore, the ammonia concentration in the reactor inlet gas is the same as the reactor outlet concentration, and the ammonia concentration is in reaction equilibrium. This circulating gas is then reintroduced into the separator. Thus, the circulating gas is
No apparent reaction or absorption occurs in the circulation line.

The concentration of aqueous ammonia can be adjusted to the desired concentration by changing the temperature and pressure of the reactor and the temperature and pressure of the ammonia separator.

With the above apparatus and operating method,
If ammonia water is extracted from the ammonia separator when it is needed, the amount of ammonia synthesis can be automatically controlled, and the raw materials can be automatically supplied, making operation extremely easy. Is. In addition, it is not necessary to frequently start or stop the device, and it is not necessary to make it in advance.

<Other Possible Embodiments> Other possible embodiments will be described below.

(1) Other examples of the arrangement of the main equipment, the raw material supply location, and the gas purging location according to the arrangement of the main equipment in the circulation line are shown in FIGS.

[0034]

[Table 1] Note: (a) to (d) do not limit the present invention supply point, but the efficient supply points are pattern 1 (b) and (c) and pattern 2 (b). .

Further, for each of the above two patterns (8 types), the location of the gas purge line can be as follows.

[0036]

[Table 2] Note: (e) to (h) are not gas purging points of the present invention, but the efficient gas purging points are (f) of patterns 1 and 2.

Of these, the following two cases were shown in the examples.

[0038]

[Table 3]

The above embodiment has the following advantages. When a compressor is installed on the upstream side of the reactor, the raw material gas is heated by compression, so that the heating amount by the heater is small and the efficiency is improved. The raw material supply point is preferably on the upstream side of the compressor where the pressure becomes the lowest in the circulation line. Further, when the raw material contains a large amount of water due to the raw material manufacturing method, the raw material supply point is preferably located upstream of the dehumidifier. The gas purging point is preferably on the downstream side of the separator.

(2) Regarding auxiliary equipment, etc., depending on the situation, tanks (buffers), mixers, heat exchangers, bypass pipes and drain pipes, vent pipes, sampling pipes, analyzers, and various instrumentation are installed in various places of the process line. Incorporate equipment, valves, safety valves, check valves, control valves, accessory piping, etc. The number of units of each device may be one, or two or more may be installed in series / parallel. A vaporizer and a distillation device may be installed in this device.

(3) Dehumidifier Dehumidifier may not be provided in the hydrogen production device, and it may be shared with the dehumidifier in the circulation line after supplying the raw materials. When a catalyst that is not easily deactivated by moisture, such as a Ru catalyst, is selected as the catalyst to be charged in the reactor, it is not necessary to select or install a dehumidifier whose dehumidification rate is not so high. When selecting a catalyst that easily deactivates against moisture, select a dehumidifier with a high dehumidification rate. However, this is to be judged comprehensively in consideration of the degree of catalyst deactivation, catalyst cost, dehumidifier cost, construction cost, operating cost, space, etc.

(4) Raw material supply method The method shown in FIGS.

[0043]

EXAMPLES [Example 1] (1) Production operation The apparatus shown in FIG. 12 was operated. A water electrolysis system was used as the hydrogen production apparatus, and a PSA apparatus was used as the nitrogen production apparatus. The amount of hydrogen supplied to the circulation line is controlled by transmitting the signal from the circulating gas pressure indicating controller to the hydrogen flow indicating controller,
Furthermore, the amount of current produced by the water electrolyzer was adjusted by this signal to control the amount of hydrogen produced. Also, regarding the amount of nitrogen supplied to the circulation line, the signal from the hydrogen flow rate indicating controller is transmitted to the hydrogen / nitrogen flow rate ratio setter whose ratio is set by the signal from the circulating gas concentration indicating controller, and the converted signal is sent. It was transmitted to and controlled by the nitrogen flow rate indicating controller. The nitrogen production apparatus was always operated so as to produce a constant flow rate of nitrogen, and excess nitrogen was released into the atmosphere. In addition, the hydrogen gas from the water electrolysis hydrogen production device is directly introduced into the circulation line without dehumidification,
A dehumidifier in the circulation line was used to dehumidify together with the circulating gas.

Tables 4, 5 and 6 show the demand for ammonia water.
1 mol-NH based on ammonia _Three/ H conversion driving condition
State.

The reactor is of a type having a heat exchanger inside and is operated while being filled with a Ru catalyst and controlled at 350 ° C. and 0.99 MPaG, and the outlet ammonia concentration is 7.35% which is close to the reaction equilibrium. A gas was obtained after the reaction. The post-reaction gas is exchanged with the inlet gas and the raw material gas-post-reaction gas heat exchanger to recover heat, and then cooled to 50 ° C with cooling water in the post-reaction gas cooler, and the three-stage bubble column type ammonia is used. Introduced into the separator. The liquid level was controlled to be constant in the separator, and 30 ° C. water was supplied at 3.99 mol / h. 1
The temperature of the ammonia water in the third stage ammonia separator is 43 ° C.
The ammonia concentration is 20.0
It was in a gas-liquid equilibrium state at mol% (19.1 wt%). The gas leaving the third stage ammonia separator had an ammonia concentration of 0.08 mol%. Here, part of the circulating gas was purged while adjusting the flow rate so that the argon concentration at the reactor inlet was 5.0%. After that, hydrogen and nitrogen are supplied while controlling the pressure of the circulating gas pressure indicating controller to be constant, and the flow rate of hydrogen is 1.6 mo.
The nitrogen flow rate was 0.5 mol / h at 1 / h. The circulating gas after supplying the raw materials was introduced into a dehumidifier and dehumidified.
The separated water was introduced into an ammonia separator. The gas after supplying hydrogen and nitrogen was pressurized to 0.99 MPaG by the circulation compressor, and the flow rate was adjusted by controlling the rotation speed of the circulation compressor. After pressurization, the gas whose flow rate was adjusted was heated in the raw material gas-post-reaction gas heat exchanger using the heat of the gas at the outlet of the reactor, and the temperature was finely adjusted by a heater before being introduced into the reactor.

By this process, 20.0 mol% (1
It was possible to obtain (9.1 wt%) aqueous ammonia. Further, even if the demand for ammonia water fluctuates, this control method enabled the operation to follow well.

(2) In the standby operation (1), the demand for ammonia water is 0 mol-N
The time when it becomes H ₃ / h is shown. Tables 7, 8 and 9 show the operating conditions at this time.

The supply of water was not supplied because the demand for ammonia disappeared and the amount of ammonia water taken out became 0, and the liquid level of the separator did not decrease from the predetermined level. The temperature of the ammonia water in the first stage ammonia separator is 43 ° C,
Ammonia concentration is 20.0 mol% (19.1 wt%)
Then, it was in a gas-liquid equilibrium state. The gas discharged from the third-stage ammonia separator has an ammonia concentration of 7.35 mol%.
And was the same as the separator inlet concentration. Purging gas amount is 0
Met. The pressure of the circulating gas pressure indicating controller was constant, and no raw material was supplied. After this, the circulating gas was pressurized to 0.99 MPaG with a compressor, and the flow rate was adjusted by controlling the rotation speed of the circulating compressor. After pressurization, the gas whose flow rate was adjusted was heated in the raw material gas-post-reaction gas heat exchanger using the heat of the gas at the outlet of the reactor, and the temperature was finely adjusted by a heater before being introduced into the reactor. Ammonia concentration of both reactor inlet gas and outlet gas was 7.35%,
No apparent new reaction occurred.

By this process, the apparatus was able to stand by automatically even when the demand for ammonia water became zero.
Inside the ammonia separator, 20.0 mol% (19.
Ammonia water (1 wt%) is accumulated and can be taken out immediately when demand for ammonia water comes out, and when taken out, the operating state (production state) of Example 1 was immediately obtained.

[Example 2] (1) Production operation In the same system as in Example 1, the case where the required concentration of aqueous ammonia is 40.5 mol% (39.2 wt%) is shown. The following conditions were changed from the operating state of Example 1. The reactor is 420 ° C. and 6.0 MPaG. The reaction equilibrium concentration at this time was 12.3 mol%. Argon concentration at reactor inlet is 8m
Adjust the purge gas flow rate to be ol%. 6 separators
6 ° C, 5.9 MPaG. 40.5 mol close to gas-liquid equilibrium
% (39.2 wt%) aqueous ammonia was obtained. Table 1
0, 11, and 12 show the operation states of the demand for ammonia water in terms of ammonia and converted to 1 ml-NH ₃ / h.

(2) Standby operation In the operation state of the system of (1), the time when there is no extraction of ammonia water is shown (automatic standby). In Tables 13, 14 and 15,
The operation state at this time is shown.

[Example 3] (1) Production operation The apparatus shown in Fig. 13 was operated. A hydrocarbon reforming device was used as the hydrogen production device, and a membrane device was used as the nitrogen production device. The amount of hydrogen supplied to the circulation line is transmitted by controlling the signal from the circulating gas pressure indicating controller to the hydrogen flow indicating controller, and this control signal is also transmitted to the hydrocarbon supplying amount indicating controller of the hydrogen production device. , The amount of hydrocarbons supplied was controlled. The amount of nitrogen supplied to the circulation line is controlled by transmitting a signal from the hydrogen flow rate indicator controller to the nitrogen flow rate indicator controller via the hydrogen / nitrogen flow rate ratio setter and then controlling it. The air supply amount was also controlled by transmitting it to the air supply amount indicating controller. Impurities in the nitrogen gas produced by the nitrogen production apparatus were 1.0% during normal operation, so the ratio setter was set to 0.3367. A control valve was installed on the hydrogen supply line and the nitrogen supply line, and the supply amount on the excess side was adjusted to be reduced or stopped by the signal from the circulating gas concentration indicating controller.

Tables 16, 17, and 18 show the operating conditions in which the demand for ammonia water is 1 mol-NH ₃ / h conversion based on ammonia.

The reactor is of a type having a heat exchanger inside, and is operated while being filled with a Ru catalyst and controlled at 330 ° C. and 0.3 MPaG, and the outlet ammonia concentration is 4.17% close to the reaction equilibrium. A gas was obtained after the reaction. The post-reaction gas exchanges heat with the inlet gas and the raw material gas-post-reaction gas heat exchanger, recovers heat, and then cools with the cooling water in the post-reaction gas cooler.
It was cooled to 0 ° C. and introduced into a packed tower type absorption tower type ammonia separator. The separator was controlled so that the liquid level was constant, and water at 30 ° C. was supplied at 13.3 mol / h. The temperature of the ammonia water at the bottom of the column was 32 ° C., the ammonia concentration was 7.0 mol% (6.6 wt%), and the gas-liquid equilibrium state was almost reached. The gas discharged from the separator was cooled to 28 ° C by a heat exchanger, and the drain generated at this time was returned to the absorption tower. The gas at the top of the tower has an ammonia concentration of 0.04mo
It was 1%. Here, part of the circulating gas was purged while adjusting the flow rate so that the argon concentration at the reactor inlet was 3.0%. After this, hydrogen and nitrogen were supplied while controlling the pressure of the circulating gas pressure indicating controller to be constant, the hydrogen flow rate was 1.6 mol / h, and the nitrogen flow rate was 0.5.
It was mol / h. The gas after supplying hydrogen and nitrogen was pressurized to 0.30 MPaG by the circulation compressor, and the flow rate of the gas after the pressure was adjusted, so that the surplus gas was spilled back to the suction side of the circulation compressor. After pressurization, the gas whose flow rate was adjusted was heated in the raw material gas-post-reaction gas heat exchanger using the heat of the gas at the outlet of the reactor, and the temperature was finely adjusted by a heater before being introduced into the reactor.

According to this process, 7.0 mol% (6.
Aqueous ammonia (6 wt%) could be obtained. Also,
Even if the demand for ammonia water fluctuates, this control method enabled the operation to follow well.

(2) Standby operation In the operation state of (1), the time when the demand for ammonia becomes 0 is shown. Tables 19, 20, and 21 show the operating conditions at this time.

The supply of water was not supplied because the demand for ammonia disappeared and the amount of ammonia water taken out became 0, and the liquid level of the separator did not decrease from the predetermined level. The temperature of the ammonia water at the bottom of the column was 32 ° C., the ammonia concentration was 7.0 mol% (6.6 wt%), and a gas-liquid equilibrium state was established. The gas exiting the separator was cooled to 28 ° C. in the separator outlet gas heat exchanger, and the drain generated at this time was returned to the absorption tower. The gas at the top of the tower has an ammonia concentration of 4.17 m.
It was the same as the absorption tower inlet concentration in ol%. The amount of purge gas was 0. The pressure of the circulating gas pressure indicating controller was constant and the raw material was not supplied. After that, the pressure of the gas was increased to 0.30 MPaG by the circulation compressor, and the excess gas was spilled back to the suction side of the circulation compressor to adjust the flow rate of the gas. After pressurization, the gas whose flow rate was adjusted was heated in the raw material gas-post-reaction gas heat exchanger using the heat of the gas at the outlet of the reactor, and the temperature was finely adjusted by a heater before being introduced into the reactor. The ammonia concentration in both the inlet gas and the outlet gas of the reactor was 4.17%, and no apparent new reaction occurred.

By this process, the apparatus can automatically stand by even when the demand for the ammonia water is exhausted, and 7.0 mol% (6.6 wt%) of the ammonia water is accumulated inside. I was able to take it out. When it was taken out, the operation state of Example 1 was obtained.

[0059]

[Table 4]

[0060]

[Table 5]

[0061]

[Table 6]

[0062]

[Table 7]

[0063]

[Table 8]

[0064]

[Table 9]

[0065]

[Table 10]

[0066]

[Table 11]

[0067]

[Table 12]

[0068]

[Table 13]

[0069]

[Table 14]

[0070]

[Table 15]

[0071]

[Table 16]

[0072]

[Table 17]

[0073]

[Table 18]

[0074]

[Table 19]

[0075]

[Table 20]

[0076]

[Table 21]

[0077]

EFFECTS OF THE INVENTION It is possible to provide an ammonia water production apparatus which can be installed on the spot near equipment using ammonia water such as a denitration apparatus and which can be easily operated.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a configuration of an ammonia water production apparatus of the present invention.

FIG. 2 is a diagram showing a circulation line portion and a raw material gas supply position of an example of the ammonia water producing apparatus of the present invention.

FIG. 3 is a diagram showing a circulation line portion and a raw material gas supply position of another example of the ammonia water producing apparatus of the present invention.

FIG. 4 is a diagram showing a circulation line section and a gas purge of an example of the ammonia water producing apparatus of the present invention.

FIG. 5 is a diagram showing a circulation line section and a gas purge of another example of the ammonia water producing apparatus of the present invention.

FIG. 6 is a diagram showing an example of a configuration of a source gas supply unit.

FIG. 7 is a diagram showing another example of the configuration of the raw material gas supply unit.

FIG. 8 is a diagram showing another example of the configuration of the raw material gas supply unit.

FIG. 9 is a diagram showing another example of the configuration of the raw material gas supply unit.

FIG. 10 is a diagram showing another example of the configuration of the raw material gas supply unit.

FIG. 11 is a diagram showing another example of the configuration of the raw material gas supply unit.

FIG. 12 is a diagram illustrating an example of a configuration of an ammonia water producing apparatus of the present invention.

FIG. 13 is a diagram showing another example of the configuration of the ammonia water producing apparatus of the present invention.

[Explanation of symbols]

101 ... Circulation compressor 102 ... Raw material gas-post-reaction gas heat exchanger 103 ... Heater 104 ... Reactor 105 ... Ammonia synthesis catalyst 106 ... Gas cooler after reaction 107 ... Ammonia separator 108 ... filling 109 ... Separator outlet gas cooler 110 ... Gas-liquid separator 111 ... Ansui pump 112 ... Anhydrous cooler 113 ... Dehumidifier 120 ... Ammonia water 201 ... Circulating gas pressure indicating controller 202 ... Hydrogen / nitrogen flow rate ratio setting device 203 ... Hydrogen flow rate indicating controller 204 ... Nitrogen flow rate indicating controller 205 ... Ammonia water temperature indicating controller 206 ... Ammonia water level indicator controller 207 ... Circulating gas concentration indicating controller 208 ... Purge gas flow rate indicator controller 209 ... Circulating gas pressure indicating controller 212 ... Circulating gas flow rate indicating controller 213 ... Ammonia water flow rate indicating controller 303 ... Hydrogen flow rate control valve 304 ... Nitrogen flow control valve 305 ... Cooling water flow control valve 306 ... Water supply control valve 308 ... Purge gas flow rate control valve 309 ... Circulating gas pressure control valve 310 ... Hydrogen supply amount adjusting valve 311 ... Nitrogen supply adjustment valve 312 ... Circulating gas flow rate control valve 313 ... Ammonia water flow rate control valve 350 ... valve

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // B01D 53/94 B01D 53/36 101A F term (reference) 4D048 AA06 AC04 CC61 CD10 4G035 AA01 AE13 AE15 4G037 BA01 BB30 CA18

Claims (2)

[Claims] 1. A reactor that is automatically controlled to keep a constant reaction temperature, and water is automatically controlled to keep a liquid level constant, and an ammonia water is automatically controlled to be constant temperature. The water absorption type ammonia separator, the dehumidifier, and the gas pressurizer are arranged in a circulation line that is automatically controlled so that the circulation flow rate is constant, and the pressure in the circulation line is constant. The reactor has a mechanism for automatically supplying hydrogen and nitrogen as raw materials, the reaction equilibrium between the ammonia raw material gas and the ammonia synthesis gas is used in the reactor, and the ammonia-containing gas and ammonia are used in the water absorption type ammonia separator. Ammonia water production equipment that uses gas-liquid equilibrium with water to supply water, hydrogen, and nitrogen by automatic control according to demand for ammonia water, and to automatically control the reaction amount 2. Ammonia water producing apparatus according to claim 1, wherein the reactor is filled with a ruthenium catalyst.