JP6815938B2 - Ammonia production increase system and method - Google Patents

Description

The present invention relates to an ammonia production increase system and method, and more particularly to an ammonia production increase system and method for increasing ammonia production from purge gas of an ammonia production plant.

Conventionally, in a chemical plant such as an ammonia production plant, hydrogen (H ₂ ) and nitrogen (N ₂ ) obtained by a steam reforming reaction or the like are predetermined in order to synthesize ammonia, for example, using natural gas or the like. Ammonia (NH ₃ ) is synthesized from the synthetic gas contained in proportion.

In such a process, after obtaining a produced gas containing ammonia in a reactor, the produced gas is cooled, ammonia is liquefied and recovered, and an unreacted gas mixture containing hydrogen and nitrogen is separated. A configuration is used in which the separated gas mixture is returned to the above-mentioned reactor via a compressor or the like to obtain a produced gas containing ammonia again (hereinafter, also referred to as an ammonia synthesis loop). Since the gas mixture contains an inert component such as methane (CH ₄ ) and argon (Ar) in addition to hydrogen and nitrogen, the inert substance is excessively accumulated in the ammonia synthesis loop. Therefore, gas (hereinafter, also referred to as purge gas) is usually extracted from the ammonia synthesis loop. The purge gas is treated by an ammonia recovery unit (ARU), and the ammonia in the purge gas is recovered, and the remaining off-gas is directly used in the fuel system in the plant (Patent Document 1). ..

In the existing ammonia production plant in which such an ammonia synthesis loop is installed, many attempts have been made to further increase the production of ammonia. For example, an upright, shell-and-tube isothermal ammonia converter that converts the purge gas of an ammonia synthesis loop to produce additional ammonia is known (Patent Document 2). According to the above document, the isothermal ammonia converter can operate the inside of the ammonia converter at an isothermal temperature by boiling pressurized water on the shell side extending vertically, and the purge gas can be passed through the ammonia converter only once. It is stated that the production volume can be increased.

Japanese Unexamined Patent Publication No. 61-106403 Japanese Unexamined Patent Publication No. 2000-143238

In addition to the methods described above, several methods can be considered to increase the production of ammonia. For example, in ARU, the off-gas after the ammonia in the purge gas has been separated still contains hydrogen. It is conceivable to newly install a hydrogen recovery unit (HRU: Hydrogen recovery unit) in the wake of ARU and add the hydrogen recovered by HRU to the syngas sent to the ammonia synthesis loop to reuse it in the ammonia synthesis reaction. .. It is also conceivable to install a pre-reformer immediately before the primary reforming of the steam reforming step, which is the pre-flow step of the ammonia synthesis loop, thereby increasing the reforming capacity.
However, the method of installing the HRU in the wake of the ARU requires sending insufficient nitrogen due to the increase in hydrogen in the synthetic gas, and the air supply amount is increased by the secondary reforming during the steam reforming process. I need to let you. In addition, it is necessary to remodel the entire existing equipment after the secondary reforming (to increase the processing capacity).
In addition, as for the method of installing the pre-reformer, it is necessary to remodel the entire existing equipment after the primary reforming (to increase the processing capacity) as the processing amount of natural gas increases. In addition, there is a problem that the operation is complicated and it is difficult to adjust the reaction even though the production increase is small.
Further, there is a problem that the expansion facility for increasing the production of ammonia affects the existing plant at the time of starting up.

In light of the above problems, the present invention can easily increase the production of ammonia in an ammonia production plant equipped with an ammonia synthesis loop by adding a necessary ammonia production increase system without requiring a major modification of the entire existing equipment. It is an object of the present invention to provide an ammonia production increase system and method which can change the amount and can start the increase of ammonia production without significantly affecting the operation of the existing plant.

One aspect of the present invention is an ammonia production increase system. The ammonia production increase system is an ammonia production increase system added to the ammonia production plant in order to further produce ammonia using the purge gas purged from the ammonia production plant, and is purged from the ammonia production plant. A first heat exchanger that heats the purge gas, a plurality of reaction means arranged in series that promote ammonia synthesis from the purge gas heated by the first heat exchanger to produce a product gas, and the plurality of reaction means. An intermediate cooling means for cooling the intermediate product gas obtained between them, a start-up reactor for raising the temperature of the purge gas or the product gas, and a gas or liquid for separating ammonia from the product gas obtained by the plurality of reaction means. A separator is provided, and the first heat exchanger is configured to raise the temperature of the purge gas by exchanging heat between the purge gas and the generated gas, and the start-up reactor is the first heat. The temperature of the purge gas in the front flow of the exchanger is raised, and the temperature of the generated gas in the front flow of the first heat exchanger, which is sent to the purge gas in the wake of the first heat exchanger or the generated gas for heat exchange, is raised. Then, it is sent to the generated gas for heat exchange, or the purge gas in the front flow of the first heat exchanger is heated and sent to the purge gas for heat exchange.
The ammonia production increase system according to the present invention can be in the form of including a plurality of the ammonia production increase systems as modules.

The start-up reactor is preferably a reactor configured to raise the temperature of the purge gas or the produced gas to 300 ° C. or higher.

The plurality of reaction means may be in the form of a plurality of reaction sections provided in one or more reaction towers, a plurality of reaction sections provided in a plurality of reactors separate from each other, or a combination thereof. .. Further, the intermediate cooling means may be in the form of a mixer that mixes the intermediate generated gas with the coolant, a cooler that exchanges heat between the intermediate produced gas and the coolant, or a combination thereof. Further, the coolant is a part of the purge gas in the form of the mixer, a part of the purge gas in the form of the cooler for heat exchange, water, air, a circulating refrigerant, or a combination thereof. can do.

Further, the start-up reactor burns a part of the purge gas in the front flow of the first heat exchanger and exchanges heat between the burned purge gas and the remaining purge gas in the second heat exchanger. The remaining purge gas is heated to be sent to the pre-flow and wake-flow purge gas of the first heat exchanger or the generated gas for heat exchange.

As one form thereof, the ammonia production increase system is configured to control the temperature of the purge gas supplied to the plurality of reaction means by using the start-up reactor and the line. As one form of the ammonia production increase system, the flow of the purge gas burned in the start-up reactor is closed, and the low temperature purge gas is sent to the wake of the first heat exchanger via the second heat exchanger. Can be configured.

As one form of the ammonia production increase system, the plurality of reaction means are further provided with a flow path configured to send the purge gas of the front flow of the first heat exchanger to the wake of the gas-liquid separator. Is a plurality of reaction units provided in the one or more reaction towers, and is configured to keep the flow rate of the purge gas to the one reaction tower constant by controlling the flow rate of the purge gas in the flow path. be able to.

The ammonia production increase system preferably further includes a flow meter for measuring the amount of separated ammonia.

Further, the present invention is, in one aspect, a method for increasing the production of ammonia. The ammonia production increase method is an ammonia production increase method for further producing ammonia using a purge gas purged from the ammonia production plant, and is a purge gas purged from the ammonia production plant using a first heat exchanger. The intermediate between the heating step of heating the gas, the step of advancing the synthesis of ammonia from the heated purge gas to produce a gas by using a plurality of reaction means arranged in series, and the plurality of reaction means. The step includes an intermediate cooling step of cooling the product gas, a start-up step of raising the purge gas or the product gas to a predetermined temperature, and a step of separating ammonia from the product gas obtained by the plurality of reaction means. In the heating step, the purge gas is heated by exchanging heat between the purge gas and the generated gas, and in the start-up step, the purge gas before the heating step is heated, and the wake of the first heat exchanger. To the purge gas or the generated gas for heat exchange, the generated gas before the heat exchange is heated and sent to the generated gas for heat exchange in the first heat exchanger, or before the heating step. The temperature of the purge gas is raised and sent to the purge gas for heat exchange by the first heat exchanger.
The method for increasing ammonia production according to the present invention can be an ammonia production increasing system including a plurality of the ammonia production increasing systems as modules.

In the start-up step, it is preferable that the reactor is configured to raise the temperature of the purge gas or the produced gas to 300 ° C. or higher.

The plurality of reaction means may be a plurality of reaction units provided in one or more reaction towers, a plurality of reaction units provided in a plurality of reactors separate from each other, or a combination thereof. Further, in the intermediate cooling step, the intermediate generated gas is mixed with the coolant and cooled, heat exchange is performed between the intermediate produced gas and the coolant using a second cooler to cool the mixture, or the intermediate cooling step is performed. These can be combined into a form. Further, the coolant is a part of the purge gas in the form of the mixer, a part of the purge gas in the form of the cooler for heat exchange, water, air, a circulating refrigerant, or a combination thereof. can do.

Further, in the start-up step, a part of the purge gas before the heating step is burned, and the purge gas burned by the second heat exchanger and the remaining purge gas are exchanged for heat to exchange the remaining purge gas. The temperature may be raised and sent to the purge gas of the front flow and the wake of the first heat exchanger or the generated gas for heat exchange.

In the method for increasing the production of ammonia, in one form thereof, the temperature of the purge gas supplied to the plurality of reaction means is controlled by using the start-up reactor and the line. In the method for increasing the production of ammonia, in one form thereof, the flow of the purge gas burned in the start-up reactor is closed, and the low-temperature purge gas is sent to the wake of the first heat exchanger via the second heat exchanger.

As one form of the method for increasing ammonia production, the flow rate adjusting step of sending the purge gas before the heating step to the wake of the gas-liquid separator after the start-up step is further provided, and the plurality of reaction means are the one. It is a plurality of reaction units provided in the above reaction tower, and in the flow rate adjusting step, the flow rate of the purge gas to the one reaction tower is made constant by controlling the flow rate of the purge gas in the flow path. Can be done.

The method for increasing ammonia production preferably further includes a flow rate measuring step for measuring the amount of separated ammonia.

According to the present invention, in an ammonia production plant equipped with an ammonia synthesis loop, the amount of increase in ammonia production can be easily changed by adding a necessary ammonia production increase system without requiring a major modification of the entire existing facility. Provided are an ammonia production increase system and a method capable of starting an ammonia production increase without significantly affecting the operation of an existing plant.

FIG. 1 is a schematic diagram illustrating a quench-type ammonia production increase system showing the first embodiment of the ammonia production increase system according to the present invention. FIG. 2 is a schematic diagram illustrating a quench type ammonia production increase system showing a second embodiment of the ammonia production increase system according to the present invention. FIG. 3 is a schematic diagram illustrating a quench type ammonia production increase system showing a third embodiment of the ammonia production increase system according to the present invention. FIG. 4 is a schematic diagram illustrating an ammonia production increase system that combines an intermediate cooling type and a quench type, showing a fourth embodiment of the ammonia production increase system according to the present invention. FIG. 5 is a schematic diagram illustrating an intermediate cooling type ammonia production increase system showing a fifth embodiment of the ammonia production increase system according to the present invention. FIG. 6 is a schematic diagram illustrating an intermediate cooling type ammonia production increase system showing a sixth embodiment of the ammonia production increase system according to the present invention. FIG. 7 is a schematic diagram for explaining a seventh embodiment of the ammonia production increase system according to the present invention. FIG. 8 is a schematic diagram for explaining an eighth embodiment of the ammonia production increase system according to the present invention. FIG. 9 is a schematic view showing the structure of an ammonia production process plant suitable for the addition of the ammonia production increase system according to the present invention.

Hereinafter, embodiments of the ammonia production increase system and method according to the present invention will be described with reference to the accompanying drawings. The present invention is not limited to the embodiments described below. In addition, the attached drawings are diagrams for explaining the outline of the present embodiment, and some of the attached devices are omitted.

[Ammonia production plant]
The first to eighth embodiments will be described with reference to FIGS. 1 to 8 for the ammonia production increase system and method according to the present invention. Prior to this, the outline of the ammonia production plant 1220 suitable for expanding the ammonia production increase system according to the present invention will be briefly described with reference to FIG.
In the ammonia production plant 1220, natural gas passes through a steam reformer (including primary reformer and secondary reformer) 1221, a carbon monoxide conversion device 1222, a carbon dioxide remover / carbon monoxide remover 1223, and the like. A synthetic gas containing hydrogen (H ₂ ) and nitrogen (N ₂ ) in a predetermined ratio is obtained. Ammonia (NH ₃ ) is synthesized from the synthetic gas in the ammonia synthesis loop 1230.
In the ammonia synthesis loop 1230, a synthetic gas containing hydrogen and nitrogen in a predetermined ratio is introduced into the ammonia synthesis tower 1231 and reacted in the presence of a catalyst to obtain ammonia. The obtained ammonia-containing gas is sent to a cooling system 1232 provided with a plurality of coolers and cooled. After that, liquid ammonia is obtained from the gas-liquid separator 1233 via the flow path 1234. The off-gas separated from the liquid ammonia is returned to the ammonia synthesis tower 1231 via the off-gas return flow path 1235, and the unreacted hydrogen and nitrogen contained in the off-gas are reused in the ammonia synthesis reaction. The off-gas return flow path 1235 is configured so that the off-gas is used as a refrigerant for a part of the coolers of the cooling system 1232, and after being used as a refrigerant for the cooler 1232c, the pressure is increased by the compressor 1236 to obtain ammonia. It is used as a refrigerant for the cooler 1232b adjacent to the upstream side of the cooler 1232c with respect to the flow direction of the contained gas.

On the other hand, in the gas circulating in the ammonia synthesis loop 1230, inactive components such as methane (CH ₄ ) and argon (Ar) are accumulated in addition to unreacted hydrogen and nitrogen and the generated ammonia. A part of the circulating gas is purged through the purge gas flow path 1225. The purge gas is cooled by the cooler 1226 provided in the purge gas flow path 1225, the liquid ammonia is separated by the gas-liquid separator 1227, and then sent to the ammonia production increase system 1 according to the present invention. Then, as will be described in detail later, after the method for increasing ammonia production according to the present invention is implemented, the off-gas is sent to the ammonia recovery unit (ARU: Ammonia Recovery Unit) 1228 via the flow path 41. Although the purge gas flow path 1225 is provided in the wake of the cooling system 1232 in the figure, it is not particularly limited to this position. Further, although the synthetic gas supply flow path 1224 is also provided at the same position, it is not particularly limited to this position.

It is particularly preferable that the ammonia production increase system 1 is provided between the ammonia synthesis loop 1230 and ARU1228. On the other hand, as described above, the ammonia production increase system 1 can be appropriately installed or removed at various locations during the ammonia production process. Therefore, if necessary, it can be provided at a position other than between the ammonia synthesis loop 1230 and ARU1228. By providing the ammonia production increase system 1 between the ammonia synthesis loop 1230 and ARU1228, the number of modified parts of the existing equipment can be extremely reduced. In addition, it can be operated continuously and at low cost flexibly according to the manufacturing situation. In addition, the high-pressure conditions required for ammonia synthesis can be maintained, and ammonia that could not be separated and collected by the ammonia production increase system is supplemented by the existing ARU in the wake. Therefore, there is an advantage that it is not necessary to perform complete separation and collection.
The ammonia production increase system 1 and the ammonia production increase method of the ammonia production plant 1220 having the above configuration will be described below with reference to FIGS. 1 to 8.

[1. First Embodiment]
First, an embodiment of the ammonia production increase system according to the present invention will be described with reference to FIG. The ammonia production increase system 1A shown in FIG. 1 includes a first heat exchanger 10, a reaction tower 20, a start-up reactor 30, and a gas-liquid separator 40. Further, in the present specification, it is expressed as "forward flow" and "backflow" with reference to the flow direction of the purge gas to be treated.

The first heat exchanger 10 is connected to the ammonia synthesis loop via the purge gas flow path 11, and is connected to the top of the reaction tower 20 (hereinafter, also referred to as an inlet) via the flow path 12, and is connected to the reaction tower 20. It is connected to the bottom of the column (hereinafter, also referred to as an outlet) via the generated gas flow path 17, and is connected to the gas-liquid separator 40 via the flow paths 18 and 19. The first heat exchanger 10 heats up the purge gas in the purge gas flow path 11 by exchanging heat between the purge gas in the purge gas flow path 11 and the production gas in the production gas flow path 17, and the reaction tower passes through the flow path 12. At the same time as sending to 20, the generated gas in the generated gas flow path 17 is cooled and sent to the flow path 18. The first heat exchanger 10 heats the purge gas in the front flow of the reaction tower 20 to a temperature suitable for the ammonia synthesis reaction by exchanging heat between the purge gas having a low temperature and the generated gas having a high temperature. This will improve the energy efficiency of the ammonia production increase system and the ammonia production plant equipped with it.

The reaction tower 20 is a reactor in which a plurality of reaction units 21a to 21c are arranged in series, and ammonia is generated from a purge gas containing at least nitrogen and hydrogen supplied to the inside of the reactor, and the ammonia concentration is increased. Is sent to the first heat exchanger 10 via the generated gas flow path 17.
Each of the plurality of reaction units 21a to 21c is filled with an ammonia synthesis catalyst therein to generate an intermediate production gas containing at least ammonia.
The ammonia synthesis catalyst is not particularly limited, and an iron-based catalyst, a ruthenium-based catalyst, or the like can be used.

Further, the reaction tower 20 further includes a plurality of mixers 22a and 22b provided between the plurality of reaction units 21a to 21c. In the reaction column 20, the first reaction section 21a, the first mixer 22a, the second reaction section 21b, the second mixer 22b, and the third reaction section 21c are arranged in this order from the top of the column to the bottom of the column. (In this specification, such a configuration is referred to as a "quenching type").
The mixers 22a and 22b are directly connected to the purge gas flow path 11 communicated with the ammonia synthesis loop via the flow paths 26a and 26b, respectively. In the mixers 22a and 22b, the intermediate generated gas is cooled by mixing the high temperature intermediate generated gas from the reaction portions 21a and 21b and the low temperature purge gas from the purge gas flow path 11, respectively. That is, the mixers 22a and 22b each function as a cooler for cooling the intermediate generated gas by sending a part of the purge gas having a low temperature from the purge gas flow path 11. In the mixers 22a and 22b, since the ammonia synthesis reaction in the plurality of reaction sections 21a to 21c is an exothermic reaction, the intermediate product gas whose temperature has risen is cooled to an appropriate temperature in order to be sent to the next reaction section. can do. The number of stages of the plurality of reaction sections and the plurality of mixers in the reaction tower 20, and the number of branch pipes of the flow path corresponding to the stages can be changed as appropriate in the same manner.

The start-up reactor 30 is connected to the purge gas flow path 11 in the front flow of the first heat exchanger 10 via the flow path 30a, and is the wake flow and reaction tower 20 of the first heat exchanger 10 through the flow path 30b. It is connected to the generated gas flow path 17 of the front flow of the above. The start-up reactor 30 includes heating means such as an electric heater (not shown), and heats the reactor 30 to, for example, 300 ° C. or higher. The flow path 30a and / or the purge gas flow path 11 may be provided with an on-off valve such as a flow rate adjusting valve (not shown) in order to control the supply of purge gas to the start-up reactor 30 and its flow rate.
In the start-up reactor 30, an electric heater, a heat medium heater, or the like can be used as a heating means for raising the temperature of the gas.

The gas-liquid separator 40 is obtained by gas-liquid separation between the flow path 19 of the generated gas cooled by the cooler 50 via the flow path 18 and the flow path 42 of the liquid ammonia obtained by gas-liquid separation. It is connected to an off-gas flow path 41 for sending a gas other than the liquid ammonia obtained to, for example, ARU. The gas-liquid separator 40 may have a structure capable of separating a gas component having a boiling point lower than that of ammonia in the produced gas from the liquid ammonia, and the structure is not particularly limited. The cooler 50 cools the generated gas by exchanging heat between the generated gas and the coolant to a temperature at which ammonia is liquefied by a gas-liquid separator 40 arranged in the subsequent flow. A plurality of coolers 50 can be provided in order to adjust the temperature to a desired level.

Next, the first embodiment of the ammonia production increase method according to the present invention will be described by explaining the operating function of the ammonia production increase system 1A having the above configuration.

When the ammonia production increase system 1A is started, the purge gas purged from the ammonia synthesis loop of the ammonia production plant is sent to the purge gas flow path 11 by opening / closing control of an on-off valve (not shown) provided in the flow path 30a and / or the purge gas flow path 11. Flows into the start-up reactor 30. In the start-up reactor 30, the purge gas is heated to a predetermined temperature (for example, about 200 to 600 ° C.) by a heating means such as an electric heater. The predetermined temperature is preferably 300 ° C. or higher from the viewpoint of the activity of the ammonia synthesis catalyst. The start-up reactor 30 sends the heated purge gas directly to the wake of the first heat exchanger 10, that is, to the inlet of the reaction tower 20. Ammonia is generated by the inflow of the heated purge gas into the reaction column 20. By such activation, the ammonia production increase system can be activated without significantly affecting the utility system of the existing ammonia production plant.

After starting the ammonia production increase system 1A, low-temperature purge gas is supplied from the purge gas flow path 11 to the first heat exchanger 10, and the temperature rises to a predetermined temperature by heat exchange with the product gas finally obtained in the reaction tower 20. Warm up. The heated purge gas is supplied to the reaction column 20 to generate ammonia. Specifically, the heated purge gas is sent from the inlet of the reaction tower 20 to the first reaction unit 21a. The temperature of the intermediate produced gas obtained by the ammonia synthesis reaction in the first reaction unit 21a has risen due to the exothermic reaction. Therefore, the first mixer 22a cools the temperature to a predetermined temperature by mixing the low-temperature purge gas from the flow path 26a. The mixed gas of the intermediate production gas and the purge gas undergoes an ammonia synthesis reaction in the second reaction section 21b. The intermediate generated gas whose temperature has risen due to the exothermic reaction is cooled to a predetermined temperature again by mixing the low-temperature purge gas from the flow path 26b in the second mixer 22b. An ammonia synthesis reaction is carried out in the third reaction section 21c, and the finally obtained product gas having a high ammonia concentration is sent from the outlet of the reaction tower 20 to the cooler 50 and the gas-liquid separator 40 via the product gas flow path 17. .. Ammonia production increase is achieved by obtaining liquid ammonia from the flow path 42 of the gas-liquid separator 40. The gas from which the liquid ammonia is separated is treated by ARU via the off-gas flow path 41, or is returned to the purge gas flow path 11 or sent to the ammonia production increase system separately installed as a module in the subsequent flow as described later. Produces ammonia. In the quench type reactor shown in the present embodiment, since the purge gas is mixed with the intermediate product gas as a coolant and used, ammonia can be generated in the reaction tower 20 without using a refrigerant. As a result, the operating cost can be suppressed.

[2. Second Embodiment]
A second embodiment of the ammonia production increase system and the ammonia production increase method according to the present invention will be described with reference to FIG. The ammonia production increase system 1B shown in FIG. 2 is mainly different from the first embodiment in that the start-up reactor 130 is provided. The same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

The start-up reactor 130 is provided with a heating means, is connected to the purge gas flow path 11 via the flow path 130a, and generates a front flow of the first heat exchanger 10 and a wake flow of the reaction tower 20 through the flow path 130b. It is connected to the gas flow path 17. As the heating means, the same configuration as that of the first embodiment can be adopted. That is, the start-up reactor 130 heats the purge gas in the purge gas flow path 11 to, for example, 300 ° C. by a heating means to raise the temperature, and the generated gas flows through the flow path 17 to exchange heat in the heat exchanger 10. Send to. In the first heat exchanger 10, the purge gas in the purge gas flow path 11 is heated by heat exchange between the low-temperature purge gas from the purge gas flow path 11 and the generated gas raised to a high temperature, and the reaction tower 20 is heated. send.

Next, a second embodiment of the ammonia production increase method according to the present invention will be described by explaining the operating function of the ammonia production increase system 1B having the above configuration. The description of the same as that of the first embodiment will be omitted.

When starting the ammonia production increase plant 1B, the purge gas purged from the ammonia synthesis loop of the ammonia production plant is sent to the start-up reactor by controlling the opening and closing of an on-off valve (not shown) provided in the flow path 130a and / or the purge gas flow path 11. It flows into 130. In the start-up reactor 130, the generated gas is heated to a predetermined temperature (for example, about 200 to 600 ° C.) by a heating means such as an electric heater. The predetermined temperature is preferably 300 ° C. or higher from the viewpoint of the activity of the ammonia synthesis catalyst. The heated generated gas is sent to the flow path 17 and merged with the generated gas for heat exchange with the purge gas in the first heat exchanger 10. Ammonia is generated by the inflow of purge gas whose temperature has been raised by heat exchange with the high-temperature production gas into the reaction column 20. By such activation, the ammonia production increase system can be activated without significantly affecting the utility system of the existing ammonia production plant.

[3. Third Embodiment]
The third embodiment of the ammonia production increase system and the ammonia production increase method according to the present invention will be described with reference to FIG. The ammonia production increase system 1C shown in FIG. 3 includes a start-up reactor 230. The same reference numerals as those of the above-described embodiments will be designated, and the description thereof will be omitted.

The start-up reactor 230 is provided with heating means, is connected to the generated gas flow path 17 of the front flow of the first heat exchanger 10 and the wake of the reaction tower 20 via the flow path 230a, and is connected to the generated gas flow path 17 via the flow path 230b. It is connected to the generated gas flow path 17 in the wake of the connection point with the flow path 230a. An on-off valve 232 such as a flow rate adjusting valve for supplying the generated gas to the start-up reactor 230 and controlling the flow rate thereof is provided on the flow path 230a. As the heating means, the same configuration as that of the above-described embodiment can be adopted. That is, the start-up reactor 230 heats the produced gas in the produced gas flow path 17 to, for example, 300 ° C. by a heating means to raise the temperature, and sends it to the first heat exchanger 10 as a high-temperature generated gas. In the first heat exchanger 10, the purge gas in the purge gas flow path 11 is heated by heat exchange between the purge gas from the purge gas flow path 11 and the generated gas heated to a high temperature, and sent to the reaction tower 20. As a result, the ammonia production increase system 1C is activated.

The flow paths 26a and 26b are connected to the purge gas flow path 11 at one end thereof, and to the mixers 22a and 22b of the reaction tower 20 at the other end, respectively. The flow paths 26a and 26b are provided with on-off valves 27a and 27b such as a flow rate adjusting valve for adjusting the inflow of purge gas into the mixers 22a and 22b, respectively. The flow paths 26a and 26b are connected to the purge gas flow path 11 at the wake of the connection point between the purge gas flow path 11 and the flow path 211, respectively.
The purge gas flow path 11 is connected to a flow path 211 for directly sending the purge gas of the purge gas flow path 11 to the off-gas flow path 41 when the system is started. The flow path 211 is provided with an on-off valve 211a such as a flow rate adjusting valve for supplying purge gas to the flow path 211 or the purge gas flow path 11 and controlling the flow rate thereof by controlling the opening / closing.

Next, the third embodiment of the ammonia production increase method according to the present invention will be described by explaining the operating function of the ammonia production increase system 1C having the above configuration. The same reference numerals as those of the above-described embodiments will be designated, and the description thereof will be omitted.

When the ammonia production increase system 1C is started, the production gas of the production gas flow path 17 flows into the start-up reactor 230 by the opening / closing control of the on-off valve 232 provided in the flow path 230. In the start-up reactor 230, the generated gas is heated to a predetermined temperature (for example, about 200 to 600 ° C.) by a heating means such as an electric heater. The predetermined temperature is preferably 300 ° C. or higher from the viewpoint of the activity of the ammonia synthesis catalyst. The heated generated gas is sent to the flow path 17 and merged with the generated gas for heat exchange with the purge gas in the first heat exchanger 10. In the first heat exchanger 10, the temperature of the purge gas is raised by heat exchange between the generated gas that has been heated to a high temperature and the purge gas that has a low temperature. Ammonia is generated by the inflow of purge gas whose temperature has been raised by heat exchange with the high-temperature production gas into the reaction column 20. By such activation, the ammonia production increase system 1C can be activated without significantly affecting the utility system of the existing ammonia production plant.

When the ammonia production increase system 1C is started, the purge gas of the ammonia synthesis loop is sent directly from the purge gas flow path 11 to the off-gas flow path 41 via the flow path 221 to allow the purge gas to flow into the first heat exchanger 10. Alternatively, the inflow amount can be adjusted. This adjustment is performed by controlling the opening / closing of the on-off valve 211a provided in the flow path 211. Further, the purge gas used for cooling in the mixers 22a and 22b by controlling the opening and closing of the on-off valves 27a and 27b provided in the flow paths 26a and 26b, respectively, at the time of starting or operating the ammonia production increase system 1C. Control inflow and inflow.

[4. Fourth Embodiment]
A fourth embodiment of the ammonia production increase system and the ammonia production increase method according to the present invention will be described with reference to FIG. In the ammonia production increase system 1D shown in FIG. 4, a plurality of reactors 120a and 120b that synthesize ammonia from the purge gas heated by the first heat exchanger 10 and an intermediate product gas between the reactor 120a and the reactor 120b are generated. A first cooler 124a for cooling is provided. The same reference numerals as those of the above-described embodiments will be designated, and the description thereof will be omitted.

The plurality of reactors 120a and 120b are formed by arranging the first reactor 120a and the second reactor 120b in series along the gas flow direction. Further, a first cooler 124a is provided between the first reactor 120a and the second reactor 120b (in the present specification, such an arrangement is referred to as an "intermediate cooling type"). Further, in the first reactor 120a, the flow path 12 to which the purge gas heated by the first heat exchanger 10 is sent and the intermediate generated gas obtained by the first reactor 120a are sent to the first cooler 124a. A flow path 13 for the purpose is provided. In the second reactor 120b, a flow path 14 for sending the intermediate product gas cooled by the first cooler 124a to the second reactor 120b and a final product gas obtained by the second reactor 120b are supplied to the second reactor 120b. A generated gas flow path 17 for sending to the first heat exchanger 10 is provided. Although only the first cooler 124a is illustrated in the figure, when there are three or more reactors, two or more coolers can be installed.

Further, each of the plurality of reactors 120a and 120b includes a plurality of reaction units 121a, 121b, 121ab and 121bb. Specifically, a plurality of reaction units 121a and 121b are arranged in series in the first reactor 120a, and a plurality of reaction units 121ab and 121bb are arranged in series in the second reactor 120b. Further, each of the plurality of reactors 120a and 120b further includes mixers 122a and 122ab provided between the plurality of reactor units 121a, 121b, 121ab and 121bb. Specifically, a mixer 122a is provided between the plurality of reaction units 121a and 121b of the first reactor 120a, and the mixer 122ab is provided between the plurality of reaction units 121ab and 121bb of the second reactor 120b. It is provided.

The mixers 122a and 122ab are directly connected to the purge gas flow path 11 communicated with the ammonia synthesis loop via the flow paths 126a and 126b, respectively. In the mixers 122a and 122ab, the intermediate generated gas is cooled by mixing the high temperature intermediate generated gas from the reaction portions 121a and 121ab and the low temperature purge gas from the purge gas flow path 11, respectively. That is, the mixers 122a and 122ab each function as a cooler for cooling the intermediate generated gas by sending a part of the purge gas having a low temperature from the purge gas flow path 11. In the mixers 122a and 122ab, since the ammonia synthesis reaction in the plurality of reaction units 121a and 121ab is an exothermic reaction, the intermediate product gas whose temperature has risen is cooled to an appropriate temperature in order to be sent to the next reaction unit. can do.

The plurality of reaction units 121a, 121b, 121ab, and 121bb are each filled with an ammonia synthesis catalyst that promotes the reaction of synthesizing ammonia from hydrogen and nitrogen. As the ammonia synthesis catalyst, the above-mentioned ammonia synthesis catalyst can be preferably adopted. Further, since the ammonia synthesis reaction of the plurality of reactors 120a and 120b is an exothermic reaction, the first cooler 124a is cooled to an appropriate temperature in order to send the intermediate product gas whose temperature has risen to the next reactor. It is something to do. A plurality of first coolers 124a can be provided in order to adjust the temperature to a desired level.

The flow path 126a is connected to the purge gas flow path 11 at one end thereof, is connected to the mixer 122a of the first reactor 120a at the other end, and the flow path 126b is connected to the purge gas flow path 11 at one end thereof. At the other end, it is connected to the mixer 122ab of the second reactor 120b. The flow paths 126a and 126b are provided with on-off valves 127a and 127b such as a flow rate adjusting valve for adjusting the inflow of purge gas into the mixers 122a and 122ab, respectively. The flow paths 126a and 126b are connected to the purge gas flow path 11 at the wake of the connection point between the purge gas flow path 11 and the flow path 211, respectively.

Next, a fourth embodiment of the ammonia production increase method according to the present invention will be described by explaining the operating function of the ammonia production increase system 1D having the above configuration.

When the ammonia production increase system 1D is started, the production gas of the production gas flow path 17 flows into the start-up reactor 230 by the opening / closing control of the on-off valve 232 provided in the flow path 230. In the start-up reactor 230, the generated gas is heated to a predetermined temperature (for example, about 200 to 600 ° C.) by a heating means such as an electric heater. The predetermined temperature is preferably 300 ° C. or higher from the viewpoint of the activity of the ammonia synthesis catalyst. The heated generated gas is sent to the flow path 17 and merged with the generated gas for heat exchange with the purge gas in the first heat exchanger 10. Ammonia is generated by the inflow of purge gas whose temperature has been raised by heat exchange with the high-temperature production gas into the reactor 120a. By such activation, the ammonia production increase system 1D can be activated without significantly affecting the utility system of the existing ammonia production plant.

When the ammonia production increase system 1D is started, the purge gas of the ammonia synthesis loop is sent directly to the off-gas flow path 41 via the purge gas flow path 11 and the flow path 211, so that the purge gas flows into the first heat exchanger 10. Alternatively, the inflow amount can be adjusted. Such control is performed by opening / closing control of the on-off valve 211a provided in the flow path 211. Further, the purge gas used for cooling in the mixers 122a and 122ab by controlling the opening and closing of the on-off valves 127a and 127b provided in the flow paths 126a and 126b, respectively, at the time of starting or operating the ammonia production increase system 1D. Control inflow and inflow.

After starting the ammonia production increase system 1D, the purge gas is supplied from the purge gas flow path 11 to the first heat exchanger 10, and the produced gas finally obtained through the plurality of reactors 120a and 120b has a predetermined temperature (for example, about about). The temperature is raised to 200 to 600 ° C.). The heated purge gas is supplied to the first reactor 120a to carry out an ammonia synthesis reaction. Since the temperature of the intermediate produced gas obtained in the first reactor 120a has risen due to the exothermic reaction, it is cooled to a predetermined temperature again in the first cooler 124a. In this way, the ammonia synthesis reaction and cooling are repeated to synthesize ammonia from hydrogen and nitrogen contained in the purge gas. The finally obtained produced gas is cooled to a predetermined temperature (10 ° C. or lower) by the cooler 50, and separated into liquid ammonia and a gas other than liquid ammonia by the gas-liquid separator 40. In addition to the ammonia production plant, this ammonia production increase system 1D can synthesize additional ammonia, resulting in an ammonia production increase.

According to the present embodiment, by installing a plurality of reactors 120a and 120b in series, the number of reactors can be increased or decreased relatively easily, so that the rate of increase in ammonia production can be adjusted. Further, when the configuration and method of providing one upright isothermal ammonia converter is adopted, the operation including the utility system becomes complicated, but as in the present embodiment, a plurality of reactors arranged in series By installing the first cooler 124a that cools the intermediate generated gas between 120a and 120b, it is easy to control the temperature of the ammonia synthesis reaction of each reactor 120a and 120b and the cooling temperature of the first cooler 124a. It becomes. This makes it possible to efficiently increase the production of ammonia from the purge gas.

[5. Fifth Embodiment]
A fifth embodiment of the ammonia production increase system and the ammonia production increase method according to the present invention will be described with reference to FIG. The ammonia production increase system shown in FIG. 5 employs and includes a plurality of the configurations of the ammonia production increase system described above as the first module 220A and the second module 220B, and further includes a start-up reactor 330. The same reference numerals as those of the above-described embodiments will be designated, and the description thereof will be omitted.

For the first module 220A and the second module 220B, the ammonia production increase system of the first to fourth embodiments described above can be suitably adopted.
The first module 220A is connected to the ammonia synthesis loop via the purge gas flow path 11A, is connected to the ARU 1228 via the off-gas flow path 141A, is connected to the start-up reactor 330 via the flow path 142, and is connected to the second module. It is connected to 220B via a purge gas flow path 11B.

The purge gas flow path 11A is provided with an on-off valve 111a electrically connected to a temperature indicator (TIC: Temperature Indicating Controller). The off-gas flow path 141A is provided with an on-off valve 141a such as a flow rate adjusting valve for sending purge gas (off-gas) from which liquid ammonia is separated by the first module 220A to ARU1228. The flow path 142 is provided with an on-off valve 142a such as a flow rate adjusting valve for sending the purge gas from which the liquid ammonia is separated by the first module 220A to the start-up reactor 330. Further, in the purge gas flow path 11B, an on-off valve 141b for sending the purge gas from which liquid ammonia is separated by the first module 220A to only the off-gas flow path 141A and an on-off valve 141b electrically connected to a temperature indicator (TIC) are opened and closed. A valve 111b is provided.

The start-up reactor 330 includes combustion means, is connected to the front flow of the first heat exchanger 10 via the flow path 330a and the flow path 330ac, and is connected to the front flow of the first heat exchanger 10 via the flow path 330b, and the first heat in the first module 220A. It is connected to the wake of the exchanger 10 and is connected to the wake of the first heat exchanger 10 in the second module 220B via the flow path 330c. The flow path 330a is provided with an on-off valve 332 such as a flow rate adjusting valve for supplying purge gas to the start-up reactor 330 and controlling the flow rate thereof.

The flow path 330a is branched into a flow path 330ab and a flow path 330ac, is connected to the second heat exchanger 310 via the flow path 330ab, and is connected to the start-up reactor 330 via the flow path 330ac. .. In the start-up reactor 330, the purge gas from the flow path 330ac is mixed with the air compressed by the compressor 331 from the flow path 330ad and then burned. The burned purge gas is sent to the second heat exchanger 310 via the flow path 330ae, and the purge gas in the flow path 330ab is heated by exchanging heat with the purge gas in the flow path 330ab in the second heat exchanger 310. To do. The heat medium after heat exchange is discharged as exhaust gas from the flow path 330ae to the outside of the system.
The purge gas in the flow path 330ab is heated in the second heat exchanger 310 by heat exchange with the gas heated by the start-up reactor 330. The heated purge gas sends the heated purge gas to the modules 220A and 220B via the flow paths 330b and 330c branched from the flow path 330af, respectively. The flow paths 330b and 330c are provided with on-off valves such as a flow rate adjusting valve for sending the heated purge gas to the modules 220A and 200220B, respectively.

The combustion means included in the start-up reactor 330 is direct combustion by furnace, combustion using a combustion catalyst, or the like. That is, the start-up reactor 330 burns a part of the purge gas of the purge gas flow path 11A by the combustion means, and heat exchanges the burned gas with the remaining purge gas to exchange the remaining purge gas with, for example, 200 to 600 ° C. The temperature is raised to 220A and 220B, respectively. The combustion catalyst may be any catalyst that can burn the purge gas.

Next, the fifth embodiment of the ammonia production increase method according to the present invention will be described by explaining the operating function of the ammonia production increase system 1E having the above configuration.

When the first module 220A is started, the on-off valve 332 is opened to send the purge gas to the flow path 330a, and the purge gas is branched into a part of the purge gas and the rest of the purge gas. After a part of the purge gas is burned by the start-up reactor 330, the remaining purge gas is heated to, for example, 300 ° C. by exchanging heat with the remaining purge gas. The remaining purge gas is sent to the wake of the first heat exchanger 10 in the first module 220A via the flow path 330af and the flow path 330b. As a result, the heated purge gas is sent to the reactor for ammonia synthesis in the first module 220A to start the first module 220A. When starting the first module 220A, the on-off valve of the flow path 330b is opened and the on-off valve of the flow path 330c is opened, so that the heat amount of the warmed purge gas is used only for starting the first module 220A. To do. Further, when the first module 220A is started, the on-off valve 111a may be opened so that the purge gas may flow into the heat exchanger 10 of the first module 220A, and the on-off valve 111a is closed. By doing so, the inflow of purge gas into the heat exchanger 10 of the first module 220A may be stopped.
Further, when the second module 220B is started, the on-off valve of the flow path 330c is closed, and the remaining purge gas is passed through the flow path 330af and the flow path 330c to the first heat exchanger 10 in the second module 220B. Send to the wake. As a result, the heated purge gas is sent to the reactor for ammonia synthesis in the second module 220B to start the second module 220B.

When starting the first module 220A, the temperature of the purge gas in the wake of the first heat exchanger 10 of the first module 220A is monitored. By controlling the opening and closing of the on-off valve 111a when the purge gas is heated to, for example, 300 ° C. or higher, the flow rate of the purge gas to the first module 220A of the purge gas flow path 11A can be controlled. Finally, while controlling the flow rate of the purge gas, the on-off valve 111a is completely opened, and the normal operation of the first module 220A is started.
During the operation of the first module 220A, the production of ammonia is increased in the first module 220A, and off-gas is sent to the wake. During the operation of the first module 220A and / or when the second module 220B is started or in operation, the on-off valve 141b is closed, the on-off valve 141a is opened, and off-gas is sent to the ARU1228 via the off-gas flow path 141A. It may be processed.

When starting the second module 220B, the temperature of the purge gas in the wake of the first heat exchanger 10 of the second module 220B is monitored. By controlling the opening and closing of the on-off valve 111b when the purge gas is heated to, for example, 300 ° C. or higher, the flow rate of the purge gas to the second module 220B of the purge gas flow path 11B is controlled. Finally, while controlling the flow rate of the purge gas, the on-off valve 111b is completely opened to shift to the normal operation of the second module 220B.
During the operation of the second module 220B, the production of ammonia is increased in the second module 220B, and the off-gas is sent to the ARU1228 via the off-gas flow path 141B.
When starting the second module 220B, the on-off valve 141b may be opened to open the on-off valve 142b, and the purge gas (off gas) of the first module 220A may be sent to the start-up reactor 330 via the flow path 142. ..

According to this embodiment, for example, when a plurality of ammonia production increase systems according to the above-described embodiment are added as modules, the purge gas heated by one start-up reactor is used in the reaction tower or reactor of each module. It is possible to start multiple modules in order from the previous stream. In addition, it is possible to activate a plurality of ammonia production increase systems divided into module units.

In this embodiment, a configuration and a method for starting the second module 220B after starting the first module 220A are illustrated. The present invention is not limited to this. By controlling the opening and closing of the on-off valves provided in the flow paths 330c and 330b, the inflow of the purge gas into the first module 220A and the inflow amount thereof until the temperature of the purge gas heat-exchanged by the second heat exchanger 310 rises sufficiently. Can also be controlled. Further, it is also possible to control the flow of the warmed purge gas into the second module 220B when the first module 220A is started, and the warmed purge gas flows into the first module 220A after the first module 220A is started. You can also control that.

Further, in the present embodiment, the purge gas heated by the start-up reactor 330 is sent to the wake of the first heat exchanger 10 of the first module 220A via the flow path 330b, and is sent through the flow path 330c. The configuration of sending to the wake of the first heat exchanger 10 of the second module 220B was illustrated. The present invention is not limited to this. According to the present embodiment, the temperature of the purge gas before being sent to the modules 220A and 220B can be raised. Therefore, as in the second to fourth embodiments, the purge gas raised by the start-up reactor 330 is heated. , It is sent to the generated gas for heat exchange in the first heat exchanger 10 of the first module 220A via the flow path 330b, and heat is generated in the first heat exchanger 10 of the second module 220B through the flow path 330c. It is possible to adopt a configuration in which the generated gas is sent for exchange. Further, for the same purpose, it is possible to adopt a configuration in which the purge gas heated by the start-up reactor 330 is sent to the purge gas flow paths 11A and 11B via the flow paths 330b and 330c, respectively. In this case, the time required for startup can be shortened.

Further, in the present embodiment, a configuration including two modules is illustrated as a plurality of modules. The present invention is not limited to this. Since a plurality of modules can be activated by one start-up reactor 330, a configuration including three or more modules can be adopted.

[6. Sixth Embodiment]
A sixth embodiment of the ammonia production increase system and the ammonia production increase method according to the present invention will be described with reference to FIG. The ammonia production increase system 1F shown in FIG. 6 is mainly different from the fifth embodiment in that the number of modules is one and a plurality of reactors 120a to 120c are provided. The same reference numerals as those of the above-described embodiments will be designated, and the description thereof will be omitted.

The plurality of reactors 120a to 120c are formed by arranging the first reactor 120a, the second reactor 120b, and the third reactor 120c in series along the gas flow direction. The first reactor 120a is provided with a reaction unit 121a, the second reactor 120b is provided with a reaction unit 121ab, and the third reactor 120c is provided with a reaction unit 121ac. As the catalyst provided in the reaction sections 121a, 121ab, and 121ac, the above-mentioned ammonia synthesis catalyst can be preferably adopted.

Further, a first cooler 124a is provided between the first reactor 120a and the second reactor 120b, and a second cooler 124b is provided between the second reactor 120b and the third reactor 120c. Has been done. The first reactor 120a has a flow path 12 to which the purge gas heated by the first heat exchanger 10 is sent, and an intermediate generated gas obtained by the first reactor 120a is sent to the first cooler 124a. A flow path 13 is provided. In the second reactor 120b, a flow path 14 for sending the intermediate product gas cooled by the first cooler 124a to the second reactor 120b and the intermediate product gas obtained by the second reactor 120b are second. A flow path 15 for sending to the cooler 124b is provided. In the third reactor 120c, a flow path 16 for sending the intermediate product gas cooled by the second cooler 124b to the third reactor 120c and the product gas obtained by the third reactor 120c are subjected to the first heat. A flow path 17 for sending to the reactor 10 is provided. That is, the plurality of reactors 120a to 120c have one reaction unit of each of the reactors 120a and 120b in the form shown in FIG. 4, and the number thereof is three.

Next, the sixth embodiment of the ammonia production increase method according to the present invention will be described by explaining the operating function of the ammonia production increase system 1F having the above configuration.

When the ammonia production increase system 1F is started, the on-off valve 332 and the on-off valve 335 are opened, the purge gas is sent to the flow path 330a, and the purge gas is branched into a part of the purge gas and the rest of the purge gas. A part of the purge gas is burned by the start-up reactor 330. By exchanging heat with the remaining purge gas during or after combustion of the purge gas, the temperature of the remaining purge gas is raised to, for example, 300 ° C. By sending the remaining purge gas to the wake of the first heat exchanger 10 via the flow path 330af, the heated purge gas is sent to the first reactor 120a, and the ammonia production increase system 1F is started.

When starting the ammonia production increase system 1F, the temperature of the purge gas in the wake of the first heat exchanger 10 and in the front of the first reactor 120a is monitored. While monitoring the inlet temperature of the first reactor 120a in this way, by controlling the opening and closing of the on-off valve 111a when the purge gas is heated to, for example, 300 ° C. or higher, the remaining purge gas flow path 330af to the first reactor The supply of the remaining purge gas to 120a and its flow rate are controlled. Finally, while controlling the flow rate of the purge gas, the on-off valve 111a is completely closed, and the normal operation of the ammonia production increase system 1F is started.

During the operation of the ammonia production increase system 1F, the on-off valve 332 is opened and the on-off valve 335 is closed, and the set temperature of the TIC electrically connected to the on-off valve 111a is changed to change the set temperature of the first reactor 120a. Control the inlet temperature.

[7. Seventh Embodiment]
The seventh embodiment of the ammonia production increase system and the ammonia production increase method according to the present invention will be described with reference to FIG. 7. The ammonia production increase system 1G shown in FIG. 7 further includes a flow path 311. The same reference numerals as those of the above-described embodiments will be designated, and the description thereof will be omitted.

The flow path 311 is connected to the front flow of the first heat exchanger 10 of the purge gas flow path 11 at one end thereof, and is connected to the off gas flow path 41 at the other end.
According to such a configuration, during the operation of the ammonia production increase system 1G, a predetermined amount of purge gas is directly sent to the off-gas flow path 41 via the flow path 311 to supply the purge gas to the reaction tower 20 and its method. Control the flow rate. In the ammonia production increase system equipped with a quench type reactor, the gas flow rate of the quenching gas flow paths 26a and 26b is controlled to control the temperature of the reaction tower 20, but when the quenching gas flow rate changes, the reaction tower 20 is moved to. The flow rate of the purge gas changes and the temperature distribution of the reaction tower 20 changes. Therefore, stable control may not be possible. Therefore, the control of the reaction tower 20 is facilitated by removing the purge gas for the control range of the quenching gas flow rate from the purge gas of the purge gas flow rate 11 from the flow rate 311 and sending the purge gas at a constant flow rate to the reaction tower 20. Can be done.

[8. Eighth embodiment]
The eighth embodiment of the ammonia production increase system and the ammonia production increase method according to the present invention will be described with reference to FIG. The ammonia production increase system 1H shown in FIG. 8 further includes a flow meter 143 for measuring the integrated flow rate of liquid ammonia. The same reference numerals as those of the above-described embodiments will be designated, and the description thereof will be omitted.
According to such a configuration, for example, when the ammonia production increase system of the above-mentioned form is added as a module to the existing plant, the amount of ammonia production increase according to the added equipment can be measured. As a result, for example, it can be used for grasping the amount of increased ammonia production in module units and for a billing service according to the amount of increased production of the ammonia production increase system.

In the present specification, natural gas is not limited to natural gas produced from gas fields, but also broadly includes unconventional natural gas such as shale gas and accompanying gas produced from oil fields accompanying oil. It includes. Natural gas as a raw material gas contains methane, which is the main component of natural gas as a product gas, and hydrocarbons of C2 or higher.

According to the ammonia production increase system and method according to the present invention, in an ammonia production plant equipped with an ammonia synthesis loop, it is possible to easily add the necessary ammonia production increase system without requiring a major modification of the entire existing equipment. The amount of increased ammonia production can be changed, and the increased production of ammonia can be started without affecting the operation of existing plants.

1, 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H: Ammonia production increase system 10: First heat exchanger 11, 11A, 11B: Purge gas flow path 20: Reaction towers 21a, 21b, 21c, 121a, 121b , 121ab, 121bb, 121ac: Reaction units 22a, 22b, 122a, 122ab: Mixer (cooler)
30, 130, 230, 330: Start-up reactor 40: Gas-liquid separator 41, 141A, 141B: Off-gas flow path 50: Coolers 120a, 120b, 120c: Reactors 124a, 124b: Cooler 220A: First module 220B: Second module 310: Second heat exchanger

Claims (23)

Ammonia production increase system added to the ammonia production plant to further produce ammonia using the purge gas purged from the ammonia production plant.
A first heat exchanger that heats the purge gas purged from the ammonia production plant,
A plurality of reaction means arranged in series, which promotes the synthesis of ammonia in the purge gas heated by the first heat exchanger to produce a gas,
An intermediate cooling means for cooling the intermediate product gas obtained among the plurality of reaction means, and an intermediate cooling means.
A start-up reactor that raises the temperature of the purge gas or the generated gas, and
A gas-liquid separator that separates ammonia from the produced gas obtained by the plurality of reaction means ,
Equipped with a flow meter for measuring the amount of separated ammonia .
The first heat exchanger is configured to raise the temperature of the purge gas by exchanging heat between the purge gas and the generated gas.
The first heat that the start-up reactor raises the temperature of the purge gas in the front flow of the first heat exchanger and sends it to the purge gas in the wake of the first heat exchanger or the generated gas for heat exchange. The temperature of the generated gas in the front flow of the exchanger is raised and sent to the generated gas for heat exchange, or the purge gas in the front flow of the first heat exchanger is heated and sent to the purge gas for heat exchange. Ammonia production increase system configured as. The ammonia production increase system according to claim 1, wherein the start-up reactor is a reactor configured to raise the temperature of the purge gas or the produced gas to 300 ° C. or higher. Claim 1 or a combination thereof, wherein the plurality of reaction means are a plurality of reaction units provided in one or more reaction towers, a plurality of reaction units provided in a plurality of reactors separate from each other, or a combination thereof. Ammonia production increase system according to 2. The intermediate cooling means is a mixer that mixes the intermediate produced gas with the coolant, a cooler that exchanges heat between the intermediate produced gas and the coolant, or a combination thereof.
The coolant is a part of the purge gas when the intermediate cooling means is a mixer, and when the intermediate cooling means is a cooler, a part of the purge gas, water, air, a circulating refrigerant, and the like. The ammonia production increase system according to any one of claims 1 to 3, which is a combination thereof. Ammonia production increase system added to the ammonia production plant to further produce ammonia using the purge gas purged from the ammonia production plant.
A first heat exchanger that heats the purge gas purged from the ammonia production plant,
A plurality of reaction means arranged in series, which promotes the synthesis of ammonia in the purge gas heated by the first heat exchanger to produce a gas,
An intermediate cooling means for cooling the intermediate product gas obtained among the plurality of reaction means, and an intermediate cooling means.
A start-up reactor that burns a part of the purge gas in the front flow of the first heat exchanger,
A second heat exchanger that exchanges heat between the burned purge gas and the remaining purge gas,
A gas-liquid separator that separates ammonia from the produced gas obtained by the plurality of reaction means is provided.
The first heat exchanger is configured to raise the temperature of the purge gas by exchanging heat between the purge gas and the generated gas.
An ammonia production increase system configured to raise the temperature of the purge gas in the front flow of the second heat exchanger and send it to the purge gas in the wake of the first heat exchanger or the generated gas for heat exchange. The ammonia production increase system according to claim 5, wherein the start-up reactor and the second heat exchanger are reactors and heat exchangers configured to raise the temperature of the purge gas to 300 ° C. or higher. The fifth or a combination thereof, wherein the plurality of reaction means are a plurality of reaction units provided in one or more reaction towers, a plurality of reaction units provided in a plurality of reactors separate from each other, or a combination thereof. Ammonia production increase system according to 6. The intermediate cooling means is a mixer that mixes the intermediate produced gas with the coolant, a cooler that exchanges heat between the intermediate produced gas and the coolant, or a combination thereof.
The coolant is a part of the purge gas when the intermediate cooling means is the mixer, and a part of the purge gas, water, air, and a circulating refrigerant when the intermediate cooling means is the cooler. , Or a combination thereof, the ammonia production increase system according to any one of claims 5 to 7. An ammonia production increase system configured to control the supply of purge gas after heat exchange and the flow rate thereof by the second heat exchanger according to any one of claims 5 to 8. A plurality of ammonia production increase systems according to any one of claims 1 to 9 are provided as modules.
The off-gas separated from the ammonia in the gas-liquid separator of the front-flow module among the plurality of modules is sent to the front-flow and wake-flow modules of the first heat exchanger or the ammonia recovery unit of the ammonia production plant. Ammonia production increase system that is configured to be sent. Further provided with a flow path configured to send the purge gas of the front flow of the first heat exchanger to the wake of the gas-liquid separator.
The plurality of reaction means are a plurality of reaction sections provided in the one or more reaction towers.
The ammonia production increase system according to any one of claims 1 to 10, wherein the flow rate of the purge gas in the flow path is controlled so that the flow rate of the purge gas to the one reaction tower becomes constant. The ammonia production increase system according to any one of claims 5 to 9 , further comprising a flow meter for measuring the amount of separated ammonia. A method of increasing ammonia production to further produce ammonia using purge gas purged from an ammonia production plant.
A heating step of heating the purge gas purged from the ammonia production plant using the first heat exchanger.
Using a plurality of reaction means arranged in series, the step of advancing the synthesis of ammonia in the heated purge gas to obtain a produced gas, and
An intermediate cooling step for cooling the intermediate product gas obtained between the plurality of reaction means,
A start-up step of raising the temperature of the purge gas or the generated gas to a predetermined temperature, and
And separating the ammonia from the product gas obtained in said plurality of reaction means,
Includes a flow rate measurement step to measure the amount of separated ammonia .
In the heating step, the purge gas is heated by exchanging heat between the purge gas and the generated gas.
In the start-up step, the temperature of the purge gas before the heating step is raised, and the temperature of the generated gas before the heat exchange, which is sent to the purge gas wake of the first heat exchanger or the generated gas for heat exchange, is raised. Ammonia, which is sent to the generated gas for heat exchange in the first heat exchanger, or the purge gas before the heating step is heated and sent to the purge gas for heat exchange in the first heat exchanger. How to increase production. The method for increasing ammonia production according to claim 13, wherein in the start-up step, the reactor is configured to raise the temperature of the purge gas or the produced gas to 300 ° C. or higher. 13 or a combination thereof, wherein the plurality of reaction means are a plurality of reaction units provided in one or more reaction towers, a plurality of reaction units provided in a plurality of reactors separate from each other, or a combination thereof. 14. The method for increasing ammonia production according to 14. The intermediate cooling step mixes the intermediate product gas with the coolant and cools the intermediate product gas, exchanges heat between the intermediate product gas and the coolant using a cooler, and cools the mixture, or a combination thereof. Including
The coolant is part of the purge gas when the intermediate cooling step is to mix and cool the intermediate produced gas with the coolant, and a cooler is used to combine the intermediate produced gas with the coolant. The ammonia production increase system according to any one of claims 13 to 15, which is a part of the purge gas, water, air, a circulating refrigerant, or a combination thereof, in the case of cooling by exchanging heat between them. .. A method for increasing the production of ammonia by using the purge gas purged from the ammonia production plant to further produce ammonia.
A heating step of heating the purge gas purged from the ammonia production plant using the first heat exchanger.
Using a plurality of reaction means arranged in series, a step of advancing the synthesis of ammonia in the purge gas heated in the first heat exchange step to obtain a produced gas, and
An intermediate cooling step for cooling the intermediate product gas obtained between the plurality of reaction means,
A start-up step of burning a part of the purge gas in the front flow of the first heat exchanger, and
A heat exchange step of heat exchange between the burned purge gas and the remaining purge gas using a second heat exchanger.
It includes a gas-liquid separation step of separating ammonia from the produced gas obtained by the plurality of reaction means.
In the heating step, the purge gas is heated by exchanging heat between the purge gas and the generated gas.
In the start-up step, an ammonia production increase system in which the temperature of the purge gas in the front flow of the second heat exchanger is raised and sent to the purge gas in the wake of the first heat exchanger or the generated gas for heat exchange. The method for increasing ammonia production according to claim 17, wherein the start-up reactor and the second heat exchanger are reactors and heat exchangers configured to raise the temperature of the purge gas to 300 ° C. or higher. 17 or a combination thereof, wherein the plurality of reaction means are a plurality of reaction units provided in one or more reaction towers, a plurality of reaction units provided in a plurality of reactors separate from each other, or a combination thereof. 18. The method for increasing ammonia production according to 18. A method for increasing ammonia production, which controls the supply of purge gas whose temperature has been raised by heat exchange in the second heat exchanger according to any one of 17 to 19 and the flow rate thereof. A plurality of ammonia production increase systems according to any one of claims 1 to 12 are provided as modules.
The off-gas generated in the front-flow module among the plurality of modules is used as the purge gas used in the start-up step in the front-flow module, the purge gas used in the heating step in the wake module, or the ammonia recovery of the ammonia production plant. Ammonia production increase method to send to the unit. After the start-up step, a flow rate adjusting step of sending the purge gas before the heating step to the wake of the gas-liquid separator is further provided.
The plurality of reaction means are a plurality of reaction sections provided in the one or more reaction towers.
The method for increasing ammonia production according to any one of claims 13 to 21, wherein in the flow rate adjusting step, the flow rate of the purge gas in the flow path is controlled to keep the flow rate of the purge gas constant in the one reaction tower. .. The method for increasing ammonia production according to any one of claims 17 to 20 , further comprising a flow rate measuring step for measuring the amount of separated ammonia.

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