JP2018203603A - Ammonia amount increasing system and method - Google Patents

Abstract

To provide an ammonia amount increasing system and method.SOLUTION: There are provided an ammonia amount increasing system 1A and method having a first heat exchanger 10 constituted to heat a purged gas, a plurality of reaction means for synthesizing ammonia from the purged gas heated with the first heat exchanger 10 and arranged in serial, internal cooling means for cooling an intermediate product gas between the plurality of reaction means, a reactor for start up 30 for increasing temperature of the purged gas or the product gas, and a gas-liquid separation device 40 for separating ammonia from the product gas obtained by the plurality of reaction means, in which the first heat exchanger 10 heat exchanges the purged gas and the product gas, and increases temperature of the purged gas, the reactor for start up 30 increases temperature of the purged gas in a front stream of the first heat exchanger 10, increases temperature of the purged gas in a back stream of the first heat exchanger 10 or the product gas in the front stream of the first heat exchanger 10, and sends the purged gas or the product gas to the product gas for heat exchange, or increases temperature of the purged gas in the front stream of the first heat exchanger 10 and sends the same to the purged gas for heat exchanger.SELECTED DRAWING: Figure 1

Description

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

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

In such a process, after a product gas containing ammonia is obtained in a reactor, the product gas is cooled, the ammonia is liquefied and recovered, and a gas mixture containing unreacted hydrogen and nitrogen is separated. A configuration is used in which the separated gas mixture is returned to the above-described reactor via a compressor or the like to obtain a product gas containing ammonia again (hereinafter also referred to as an ammonia synthesis loop). Since the gas mixture contains inert components such as methane (CH ₄ ) and argon (Ar) in addition to hydrogen and nitrogen, the inert material accumulates excessively in the ammonia synthesis loop. For this reason, gas (hereinafter also referred to as purge gas) is normally extracted from the ammonia synthesis loop. The purge gas is processed by an ammonia recovery unit (ARU: Ammonia Recovery Unit), 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 an 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 type isothermal ammonia converter that converts the purge gas of the ammonia synthesis loop to generate additional ammonia is known (Patent Document 2). In the above document, an isothermal ammonia converter boils pressurized water on the vertically extending shell side, so that the inside of the ammonia converter can be operated isothermally, and the purge gas is passed through the ammonia converter only once. It is described that the production amount can be increased.

JP 61-106403 A JP 2000-143238 A

In addition to the methods described above, several methods are conceivable for increasing the production of ammonia. For example, in ARU, the off-gas after the ammonia in the purge gas has been separated still contains hydrogen. A hydrogen recovery unit (HRU) may be newly installed in the downstream of the ARU, and the hydrogen recovered by the HRU may be reused in the ammonia synthesis reaction by adding it to the synthesis gas sent to the ammonia synthesis loop. . It is also conceivable to install a pre-reformer immediately before the primary reforming of the steam reforming process, which is a process upstream of the ammonia synthesis loop, thereby increasing the reforming capacity.
However, the method of installing the HRU in the downstream of the ARU requires sending insufficient nitrogen as the amount of hydrogen in the synthesis gas increases, increasing the air supply volume in the secondary reforming during the steam reforming process. It is necessary to let In addition, it is necessary to modify the entire existing equipment after the secondary reforming (to increase the throughput capacity).
In addition, the method of installing the pre-reformer needs to modify the entire existing equipment after the primary reforming (in order to increase the throughput capacity) as the natural gas throughput increases. In addition, despite the small increase in production, there is a problem that operation is complicated and reaction adjustment is difficult.
Furthermore, there is a problem that the extension equipment for increasing the production of ammonia affects the existing plant at the time of start-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 system without requiring significant remodeling of the entire existing equipment. An object of the present invention is to provide an ammonia production system and method capable of changing the amount and starting production of ammonia without greatly affecting the operation of an existing plant.

In one aspect, the present invention is an ammonia production increase system. The ammonia production system is an ammonia production system that is added to the ammonia production plant to further produce ammonia using a 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, in which ammonia synthesis proceeds from the purge gas heated in 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, a start-up reactor for raising the temperature of the purge gas or the product gas, and a gas-liquid for separating ammonia from the product gas obtained by the plurality of reaction means A separator, wherein the first heat exchanger exchanges heat between the purge gas and the product gas. The purge gas is configured to raise the temperature of the purge gas, the startup reactor raises the temperature of the purge gas upstream of the first heat exchanger, and the purge gas or the heat downstream of the first heat exchanger. The temperature of the product gas upstream of the first heat exchanger is sent to the product gas for exchange, and the temperature is sent to the product gas for heat exchange, or the purge gas upstream of the first heat exchanger is sent The temperature is raised and sent to the purge gas for heat exchange.
The ammonia production system according to the present invention may be configured to include a plurality of the ammonia production systems as modules.

  The startup reactor is preferably a reactor configured to raise the temperature of the purge gas or the product gas to 300 ° C. or higher.

  The plurality of reaction means may be in the form of 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. . The intermediate cooling means may be a mixer that mixes the intermediate product gas with a coolant, a cooler that exchanges heat between the intermediate product gas and the coolant, or a combination thereof. The coolant may be a part of the purge gas in the form of the mixer, a part of the purge gas, water, air, a circulating refrigerant, or a combination of these in the form of the cooler that performs the heat exchange. can do.

  The start-up reactor combusts a part of the purge gas upstream 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 and sent to the upstream or downstream purge gas of the first heat exchanger or the product gas for heat exchange.

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

  The ammonia production system further includes, as one form thereof, a flow path configured to send the purge gas upstream of the first heat exchanger to the downstream of the gas-liquid separator, and the plurality of reaction means Are a plurality of reaction units provided in the one or more reaction towers, and the purge gas flow rate to the one reaction tower is made constant by controlling the flow rate of the purge gas in the flow path. be able to.

  It is preferable that the ammonia production system further includes a flow meter for measuring the amount of the separated ammonia.

Moreover, this invention is the ammonia production increase method in the one side surface. The ammonia production method is an ammonia production method for further producing ammonia using a purge gas purged from an ammonia production plant, wherein the purge gas purged from the ammonia production plant using a first heat exchanger Using a plurality of reaction means arranged in series, a step of advancing ammonia synthesis from the heated purge gas to produce a product gas, and an intermediate obtained between the plurality of reaction means An intermediate cooling step for cooling the product gas, a start-up step for 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, heat exchange is performed between the purge gas and the product gas. The temperature of the purge gas is raised, and in the startup step, the temperature of the purge gas before the heating step is raised and sent to the purge gas downstream of the first heat exchanger or the product gas for heat exchange, before the heat exchange. The generated gas is heated and sent to the generated gas for heat exchange in the first heat exchanger, or the purge gas before the heating step is heated, and the heat exchange is performed in the first heat exchanger. To be sent to the purge gas.
The method for increasing ammonia production according to the present invention can be an ammonia production system comprising a plurality of the ammonia production systems as modules.

  In the start-up step, the reactor is preferably configured to raise the temperature of the purge gas or the product 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 separate reactors, or a combination thereof. In the intermediate cooling step, the intermediate product gas is mixed with a coolant and cooled, the second cooler is used for heat exchange between the intermediate product gas and the coolant, or cooling, or It can be set as the form which combined these. The coolant may be a part of the purge gas in the form of the mixer, a part of the purge gas, water, air, a circulating refrigerant, or a combination of these in the form of the cooler that performs the heat exchange. can do.

  Further, in the start-up step, a part of the purge gas before the heating step is combusted, and the purge gas burned using the second heat exchanger is heat-exchanged with the remaining purge gas to thereby change the remaining purge gas. The temperature may be raised and sent to the upstream or downstream purge gas of the first heat exchanger or the product gas for heat exchange.

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

  The ammonia production method further includes, as one form thereof, a flow rate adjusting step of sending the purge gas before the heating step to the downstream of the gas-liquid separator after the start-up step, and the plurality of reaction means are the one of the ones A plurality of reaction units provided in the 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 do.

  It is preferable that the ammonia production increase method further includes a flow rate measuring step of measuring the amount of the separated ammonia.

  According to the present invention, in an ammonia production plant equipped with an ammonia synthesis loop, it is possible to easily change the amount of increased ammonia production by installing a necessary ammonia production system without requiring significant remodeling of the entire existing equipment. In addition, an ammonia production system and method that can start production of ammonia without greatly affecting the operation of an existing plant are provided.

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

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

[Ammonia production plant]
About the ammonia production increase system and method which concern on this invention, 1st-8th embodiment is described with reference to FIGS. Prior to this, the outline of an ammonia production plant 1220 suitable for adding an ammonia production 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 reforming and secondary reforming) 1221, a carbon monoxide converter 1222, a carbon dioxide removing device / carbon monoxide removing device 1223, and the like. Thus, a synthesis gas containing hydrogen (H ₂ ) and nitrogen (N ₂ ) in a predetermined ratio is obtained. Ammonia (NH ₃ ) is synthesized from the synthesis gas in the ammonia synthesis loop 1230.
In the ammonia synthesis loop 1230, synthesis 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 including a plurality of coolers and cooled. Thereafter, 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 channel 1235, and unreacted hydrogen and nitrogen contained in the off-gas are reused for the ammonia synthesis reaction. The off-gas return flow path 1235 is configured so that off-gas is used as a refrigerant of a cooler of a part of the cooling system 1232, and after being used as a refrigerant of the cooler 1232 c, the pressure is increased by the compressor 1236 and ammonia The refrigerant is used as a refrigerant of 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 through the ammonia synthesis loop 1230, inactive components such as methane (CH ₄ ) and argon (Ar) accumulate in addition to unreacted hydrogen, nitrogen, and generated ammonia. A part of the circulating gas is purged through the purge gas flow path 1225. The purge gas is cooled by a cooler 1226 provided in the purge gas flow path 1225, and after liquid ammonia is separated by a gas-liquid separator 1227, the purge gas is sent to the ammonia production system 1 according to the present invention. As will be described in detail later, after the ammonia production method according to the present invention is performed, the off-gas is sent to an ammonia recovery unit (ARU) 1228 via the flow path 41. Note that the purge gas flow path 1225 is provided downstream of the cooling system 1232 in the drawing, but is not particularly limited to this position. Further, the syngas supply flow path 1224 is also provided at the same position, but is not particularly limited to this position.

The ammonia production system 1 is particularly preferably provided between the ammonia synthesis loop 1230 and the ARU 1228. On the other hand, as described above, the ammonia production-increasing system 1 can be appropriately installed or removed at various locations during the ammonia production process. For this reason, it can also be provided in places other than between the ammonia synthesis loop 1230 and the ARU 1228 as necessary. By providing the ammonia production system 1 between the ammonia synthesis loop 1230 and the ARU 1228, the remodeling part of the existing equipment can be extremely reduced. In addition, it becomes possible to operate continuously and at low cost according to the manufacturing situation. Moreover, the high pressure conditions required for ammonia synthesis can be maintained, and ammonia that cannot be separated and collected by the ammonia production system is supplemented by the existing ARU in the downstream. For this reason, there is an advantage that it is not necessary to perform complete separation and collection.
The ammonia production system 1 and the ammonia production method of the ammonia production plant 1220 having the above configuration will be described below with reference to FIGS.

[1. First embodiment]
First, an embodiment of the ammonia production system according to the present invention will be described with reference to FIG. An ammonia production 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 this specification, the flow direction of the purge gas to be processed is used as a reference and is expressed as “front flow” or “back flow”.

  The first heat exchanger 10 is connected to the ammonia synthesis loop via the purge gas flow path 11, and connected to the top of the reaction tower 20 (hereinafter also referred to as an inlet) via the flow path 12. The bottom of the column (hereinafter also referred to as the outlet) is connected to the product gas channel 17, and the gas-liquid separator 40 is connected to the channels 18 and 19. The first heat exchanger 10 heats the purge gas in the purge gas channel 11 and the product gas in the product gas channel 17 to increase the temperature of the purge gas in the purge gas channel 11, and the reaction tower through the channel 12 20, the product gas in the product gas channel 17 is cooled and sent to the channel 18. The first heat exchanger 10 heats the purge gas upstream of the reaction tower 20 to a temperature suitable for the ammonia synthesis reaction by exchanging heat between the low temperature purge gas and the high temperature generated gas. This improves the energy efficiency of the ammonia production system and the ammonia production plant equipped therewith.

The reaction tower 20 is a reactor in which a plurality of reaction sections 21a to 21c are arranged in series. The reaction tower 20 generates ammonia from a purge gas containing at least nitrogen and hydrogen supplied into the reaction tower 20 and increases the ammonia concentration. Is sent to the first heat exchanger 10 via the product gas flow path 17.
Each of the plurality of reaction units 21a to 21c is filled with an ammonia synthesis catalyst to generate an intermediate product gas containing at least ammonia.
There is no restriction | limiting in particular as an ammonia synthesis catalyst, An iron-type catalyst, a ruthenium-type catalyst, etc. can be used.

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 tower 20, a first reaction section 21a, a first mixer 22a, a second reaction section 21b, a second mixer 22b, and a third reaction section 21c are arranged in this order from the tower top to the tower bottom. (This configuration is referred to as “quenching type” in this specification).
The mixers 22a and 22b are directly connected to each other via the purge gas channel 11 and the channels 26a and 26b communicating with the ammonia synthesis loop. In the mixers 22a and 22b, the intermediate product gas is cooled by mixing the intermediate product gas having a high temperature from the reaction units 21a and 21b and the purge gas having a low temperature from the purge gas flow path 11, respectively. That is, the mixers 22a and 22b function as coolers for cooling the intermediate product gas when a part of the purge gas having a low temperature from the purge gas flow path 11 is sent. In the mixers 22a and 22b, the ammonia synthesis reaction in the plurality of reaction units 21a to 21c is an exothermic reaction. can do. In addition, the number of stages of the plurality of reaction units and the plurality of mixers in the reaction tower 20 and the number of installed branch pipes corresponding to the same can be changed as appropriate.

The start-up reactor 30 is connected to the purge gas flow path 11 that is upstream of the first heat exchanger 10 via the flow path 30a, and is connected to the downstream side of the first heat exchanger 10 and the reaction tower 20 via the flow path 30b. Are connected to the product gas flow path 17 in the upstream. The start-up reactor 30 includes heating means such as an electric heater (not shown), and heats the reactor to, for example, 300 ° C. or higher. The flow path 30a and / or the purge gas flow path 11 can be provided with an open / close valve such as a flow rate adjusting valve (not shown) in order to control the supply of the purge gas to the start-up reactor 30 and the flow rate thereof.
As a heating means for raising the temperature of the gas in the start-up reactor 30, an electric heater, a heat medium heater, or the like can be used.

  The gas-liquid separator 40 is obtained by gas-liquid separation, with the product gas channel 19 cooled by the cooler 50 through the channel 18, the liquid ammonia channel 42 obtained by gas-liquid separation, and the gas-liquid separation. For example, the gas other than the liquid ammonia is connected to an off-gas passage 41 for sending the gas to the ARU. The gas-liquid separator 40 is not particularly limited as long as it has a configuration capable of separating a gas component having a boiling point lower than that of ammonia in the generated gas from liquid ammonia. The cooler 50 cools the product gas by exchanging heat between the product gas and the coolant up to a temperature at which ammonia is liquefied by the gas-liquid separator 40 disposed downstream. A plurality of coolers 50 can be provided in order to adjust to a desired temperature.

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

  When the ammonia production system 1A is started, the purge gas channel 11 is purged from the ammonia synthesis loop of the ammonia production plant by opening / closing control of an opening / closing valve (not shown) provided in the channel 30a and / or the purge gas channel 11. To 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 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 downstream of the first heat exchanger 10, that is, directly to the inlet of the reaction tower 20. As the purge gas heated to the reaction tower 20 flows, ammonia is generated. By such activation, the ammonia production system can be activated without greatly affecting the utility system of the existing ammonia production plant.

  After the startup of the ammonia production system 1A, a low temperature purge gas is supplied from the purge gas flow path 11 to the first heat exchanger 10, and the temperature is raised to a predetermined temperature by heat exchange with the product gas finally obtained in the reaction tower 20. Warm up. The purge gas whose temperature has been raised is supplied to the reaction tower 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 product gas obtained by the ammonia synthesis reaction in the first reaction unit 21a is increased by an exothermic reaction. For this reason, the first mixer 22a is cooled to a predetermined temperature by mixing the low-temperature purge gas from the flow path 26a. The mixed gas of the intermediate product gas and the purge gas performs an ammonia synthesis reaction in the second reaction section 21b. The intermediate product gas whose temperature has increased due to the exothermic reaction is cooled again to a predetermined temperature by mixing the low temperature purge gas from the flow path 26b in the second mixer 22b. Ammonia synthesis reaction is performed 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 through the product gas channel 17. . Increased production of ammonia is achieved by obtaining liquid ammonia from the flow path 42 of the gas-liquid separator 40. The gas from which liquid ammonia has been separated is processed in the ARU via the off-gas channel 41 or, as will be described later, is sent back to the purge gas channel 11 or sent to an ammonia production system installed as a separate module downstream thereof, Ammonia production. In the quench type reactor shown in the present embodiment, the purge gas is used as a coolant mixed with the intermediate product gas, so that 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]
With reference to FIG. 2, a second embodiment of the ammonia production system and the ammonia production method according to the present invention will be described. Ammonia production system 1B shown in FIG. 2 is mainly different from the first embodiment in that a startup reactor 130 is provided. About the structure similar to 1st embodiment, while attaching | subjecting the same code | symbol, description is abbreviate | omitted.

  The start-up reactor 130 includes heating means, is connected to the purge gas flow path 11 via the flow path 130a, and generates the upstream flow of the first heat exchanger 10 and the downstream flow of the reaction tower 20 via the flow path 130b. It is connected to the gas flow path 17. About a heating means, the structure similar to 1st embodiment is employable. 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, raises the temperature, and flows through the flow path 17 to exchange heat in the heat exchanger 10. Send to. In the first heat exchanger 10, the temperature of the purge gas in the purge gas flow path 11 is raised by exchanging heat between the low temperature purge gas from the purge gas flow path 11 and the product gas heated to a high temperature. send.

  Next, the second embodiment of the ammonia production method according to the present invention will be described by explaining the operation function of the ammonia production system 1B having the above configuration. The description of the same components as those in the first embodiment is omitted.

  When starting up the ammonia production plant 1B, the purge gas purged from the ammonia synthesis loop of the ammonia production plant is controlled by opening and closing a not-shown on-off valve provided in the flow path 130a and / or the purge gas flow path 11 to start up the reactor. 130 flows. In the start-up reactor 130, the product gas is heated to a predetermined temperature (for example, about 200 to 600 ° C.) by 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 product gas is sent to the flow path 17 and joined to the product gas for heat exchange with the purge gas in the first heat exchanger 10. A purge gas heated by heat exchange with a high-temperature product gas flows into the reaction tower 20 to generate ammonia. By such activation, the ammonia production system can be activated without greatly affecting the utility system of the existing ammonia production plant.

[3. Third embodiment]
With reference to FIG. 3, a third embodiment of the ammonia production system and the ammonia production method according to the present invention will be described. Ammonia production system 1C shown in FIG. The same components as those in the above-described embodiment are denoted by the same reference numerals and the description thereof is omitted.

  The start-up reactor 230 includes heating means, and is connected to the product gas channel 17 upstream of the first heat exchanger 10 and downstream of the reaction tower 20 via the channel 230a, and via the channel 230b. It is connected to the product gas flow path 17 downstream of the connection point with the flow path 230a. On the flow path 230a, an open / close valve 232 such as a flow rate adjusting valve for controlling the supply of the product gas to the start-up reactor 230 and the flow rate thereof is provided. About the heating means, the structure similar to embodiment mentioned above is employable. That is, the startup reactor 230 heats the product gas in the product gas flow path 17 to, for example, 300 ° C. by a heating means, and sends it to the first heat exchanger 10 as a high-temperature product gas. In the first heat exchanger 10, the purge gas from the purge gas flow path 11 and the product gas heated to a high temperature are subjected to heat exchange to raise the temperature of the purge gas in the purge gas flow path 11 and send it to the reaction tower 20. This activates the ammonia production system 1C.

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

  Next, a description will be given of a third embodiment of the ammonia production method according to the present invention by explaining the operation function of the ammonia production system 1C having the above configuration. The same components as those in the above-described embodiment are denoted by the same reference numerals and the description thereof is omitted.

  When the ammonia production system 1 </ b> C is started, the product gas in the product gas channel 17 flows into the startup reactor 230 by opening / closing control of the on-off valve 232 provided in the channel 230. In the start-up reactor 230, the product gas is heated to a predetermined temperature (for example, about 200 to 600 ° C.) by 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 product gas is sent to the flow path 17 and joined to the product gas for heat exchange with the purge gas in the first heat exchanger 10. The first heat exchanger 10 raises the temperature of the purge gas by exchanging heat between the product gas heated to a high temperature and the low-temperature purge gas. A purge gas heated by heat exchange with a high-temperature product gas flows into the reaction tower 20 to generate ammonia. By such activation, the ammonia production system 1C can be activated without greatly affecting the utility system of the existing ammonia production plant.

  When the ammonia production system 1C is started, the purge gas flows into the first heat exchanger 10 by directly sending the purge gas of the ammonia synthesis loop from the purge gas channel 11 to the off-gas channel 41 via the channel 221. Alternatively, the inflow amount can be adjusted. This adjustment is performed by opening / closing control of the opening / closing valve 211 a provided in the flow path 211. Further, when the ammonia production system 1C is started up or during operation, the on-off valves 27a and 27b provided in the flow paths 26a and 26b are controlled to be opened and closed, so that the purge gas used for cooling in the mixers 22a and 22b is controlled. Control inflow and inflow.

[4. Fourth embodiment]
With reference to FIG. 4, a fourth embodiment of the ammonia production system and the ammonia production method according to the present invention will be described. In the ammonia production 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 intermediate product gas between the reactor 120a and the reactor 120b. A first cooler 124a for cooling is provided. The same components as those in the above-described embodiment are denoted by the same reference numerals and the description thereof is omitted.

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

  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. Each of the plurality of reactors 120a and 120b further includes mixers 122a and 122ab provided between the plurality of reaction units 121a, 121b, 121ab, and 121bb. Specifically, a mixer 122a is provided between the plurality of reaction parts 121a and 121b of the first reactor 120a, and a mixer 122ab is provided between the plurality of reaction parts 121ab and 121bb of the second reactor 120b. Is provided.

  The mixers 122a and 122ab are directly connected to each other via the purge gas channel 11 and the channels 126a and 126b communicating with the ammonia synthesis loop. In the mixers 122a and 122ab, the intermediate product gas having a high temperature from the reaction units 121a and 121ab and the purge gas having a low temperature from the purge gas channel 11 are mixed to cool the intermediate product gas. That is, the mixers 122a and 122ab function as coolers for cooling the intermediate product gas when a part of the purge gas having a low temperature from the purge gas flow path 11 is sent. 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 been increased 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 filled with an ammonia synthesis catalyst that promotes a reaction of synthesizing ammonia from hydrogen and nitrogen, respectively. As the ammonia synthesis catalyst, the above-described ammonia synthesis catalyst can be suitably employed. In addition, 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. To do. Note that a plurality of first coolers 124a can be provided in order to adjust to a desired temperature.

  The flow path 126a is connected to the purge gas flow path 11 at one end, 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. The other end is connected to the mixer 122ab of the second reactor 120b. The channels 126a and 126b are provided with on-off valves 127a and 127b such as flow rate adjusting valves for adjusting the flow 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 downstream of the connection location between the purge gas flow path 11 and the flow path 211, respectively.

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

  When the ammonia production system 1D is started, the product gas in the product gas channel 17 flows into the start-up reactor 230 by opening / closing control of the on-off valve 232 provided in the channel 230. In the start-up reactor 230, the product gas is heated to a predetermined temperature (for example, about 200 to 600 ° C.) by 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 product gas is sent to the flow path 17 and joined to the product gas for heat exchange with the purge gas in the first heat exchanger 10. The purge gas heated by heat exchange with the high-temperature product gas flows into the reactor 120a, whereby ammonia is generated. By such activation, the ammonia production system 1D can be activated without significantly affecting the utility system of the existing ammonia production plant.

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

  After activation of the ammonia production system 1D, purge gas is supplied from the purge gas flow path 11 to the first heat exchanger 10, and the product gas finally obtained through the plurality of reactors 120a, 120b is used at a predetermined temperature (for example, about The temperature is increased to 200-600 ° C. The purge gas whose temperature has been raised is supplied to the first reactor 120a to perform the ammonia synthesis reaction. Since the temperature of the intermediate product gas obtained in the first reactor 120a has risen due to the exothermic reaction, it is cooled again to a predetermined temperature by the first cooler 124a. Thus, ammonia synthesis reaction and cooling are repeated, and ammonia is synthesized from hydrogen and nitrogen contained in the purge gas. The finally obtained product gas is cooled to a predetermined temperature (10 ° C. or less) 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, additional ammonia can be synthesized by this ammonia production system 1D, and as a result, increased production of ammonia is achieved.

  According to the present embodiment, by installing the 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. In addition, when adopting a configuration and method in which one tower of an upright type isothermal ammonia converter is adopted, the operation is complicated including the utility system, but a plurality of reactors arranged in series as in this embodiment. By installing the first cooler 124a that cools the intermediate product gas between 120a and 120b, it is easy to control the temperature of the ammonia synthesis reaction of each of the reactors 120a and 120b and the cooling temperature of the first cooler 124a. It becomes. Thereby, it is possible to increase the production of ammonia from the purge gas efficiently.

[5. Fifth embodiment]
With reference to FIG. 5, a fifth embodiment of the ammonia production system and the ammonia production method according to the present invention will be described. The ammonia production system shown in FIG. 5 includes a plurality of configurations of the above-described ammonia production system as the first module 220A and the second module 220B, and further includes a startup reactor 330. The same components as those in the above-described embodiment are denoted by the same reference numerals and the description thereof is omitted.

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

  The purge gas channel 11A is provided with an on-off valve 111a that is electrically connected to a temperature indicating controller (TIC). The off-gas channel 141A is provided with an on-off valve 141a such as a flow rate adjusting valve for sending a purge gas (off-gas) obtained by separating the liquid ammonia by the first module 220A to the ARU 1228. The flow path 142 is provided with an open / close valve 142 a such as a flow rate adjusting valve for sending the purge gas from which the liquid ammonia has been separated by the first module 220 </ b> A to the start-up reactor 330. The purge gas channel 11B has an open / close valve 141b for sending the purge gas separated from the liquid ammonia by the first module 220A only to the off gas channel 141A, and an open / close unit electrically connected to the temperature indicating controller (TIC). A valve 111b is provided.

  The start-up reactor 330 includes combustion means, is connected to the upstream of the first heat exchanger 10 via the flow path 330a and the flow path 330ac, and is connected to the first heat in the first module 220A via the flow path 330b. It connects with the back flow of the exchanger 10, and is connected with the back flow of the 1st heat exchanger 10 in the 2nd 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 controlling the supply of the purge gas to the start-up reactor 330 and the flow rate thereof.

The flow path 330a branches 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 combusted purge gas is sent to the second heat exchanger 310 through the flow path 330ae, and the second heat exchanger 310 exchanges heat with the purge gas in the flow path 330ab, thereby raising the temperature of the purge gas in the flow path 330ab. To do. The heat medium after the heat exchange is discharged out of the system from the flow path 330ae as exhaust gas.
The purge gas in the flow path 330ab is heated by the second heat exchanger 310 by heat exchange with the gas heated by the start-up reactor 330. The purge gas whose temperature has been increased sends the purge gas whose temperature has been increased to the modules 220A and 220B through 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 flow rate adjusting valves for sending the purge gas whose temperature has been raised to the modules 220A and 200220B, respectively.

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

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

When the first module 220A is activated, by opening the on-off valve 332, 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 remaining 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 downstream of the first heat exchanger 10 in the first module 220A via the flow paths 330af and 330b. As a result, the purge gas that has been heated 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 purge gas that has been heated is used only for starting the first module 220A. To do. Further, when the first module 220A is activated, the on-off valve 111a may be opened to allow purge gas to flow into the heat exchanger 10 of the first module 220A, and the on-off valve 111a may be closed. By doing so, the purge gas may be prevented from flowing into the heat exchanger 10 of the first module 220A.
Further, when the second module 220B is activated, 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 downstream. Thereby, the purge gas which has been heated is sent to the ammonia synthesis reactor in the second module 220B, and the second module 220B is activated.

When starting the first module 220A, the temperature of the purge gas downstream of the first heat exchanger 10 of the first module 220A is monitored. 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 in the purge gas flow path 11A can be controlled by controlling the opening / closing valve 111a. While controlling the flow rate of the purge gas, the on-off valve 111a is finally completely opened, and the normal operation of the first module 220A is started.
During the operation of the first module 220A, the first module 220A increases the production of ammonia and the off-gas is sent to the downstream. During the operation of the first module 220A and / or during the start-up or operation of the second module 220B, the on-off valve 141b is closed and the on-off valve 141a is opened, and off gas is sent to the ARU 1228 via the off gas channel 141A. It may be processed.

When starting the second module 220B, the temperature of the purge gas downstream of the first heat exchanger 10 of the second module 220B is monitored. 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 in the purge gas flow path 11B is controlled by controlling the opening / closing valve 111b. While controlling the flow rate of the purge gas, the on-off valve 111b is finally completely opened, and the second module 220B is shifted to normal operation.
During operation of the second module 220B, ammonia is increased in the second module 220B, and off-gas is sent to the ARU 1228 via the off-gas channel 141B.
When starting the second module 220B, the on-off valve 141b is opened, the on-off valve 142b is opened, 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 the present embodiment, for example, when a plurality of ammonia production systems according to the above-described embodiments are additionally installed as modules, the purge gas heated by one start-up reactor is used as the reaction tower or reactor of each module. Multiple modules can be started in order from the front stream. In addition, a plurality of ammonia production systems divided into modules can be activated.

  In the present embodiment, the configuration and the method of starting the second module 220B after starting the first module 220A are exemplified. The present invention is not limited to this. The purge gas flows into the first module 220A and the amount of the flow until the temperature of the purge gas heat-exchanged by the second heat exchanger 310 is sufficiently raised by the opening / closing control of the on-off valves provided in the flow paths 330c and 330b. Can also be controlled. In addition, it is possible to control the purge gas that has been heated when the first module 220A is started to flow into the second module 220B, and the purge gas that has been heated after the first module 220A is started flows into the first module 220A. You can also control this.

  Further, in the present embodiment, the purge gas heated in the start-up reactor 330 is sent to the downstream of the first heat exchanger 10 of the first module 220A via the flow path 330b, and via the flow path 330c. The structure sent to the downstream of the 1st heat exchanger 10 of the 2nd module 220B was illustrated. The present invention is not limited to this. According to the present embodiment, since the temperature of the purge gas before being sent to the modules 220A and 220B can be raised, the purge gas heated in the start-up reactor 330 can be heated similarly to the second to fourth embodiments. And sent to the product gas for heat exchange in the first heat exchanger 10 of the first module 220A via the flow path 330b, and heat in the first heat exchanger 10 of the second module 220B via the flow path 330c. It is possible to adopt a configuration for sending the product gas to be exchanged. For the same purpose, it is possible to adopt a configuration in which the purge gas heated in the start-up reactor 330 is sent to the purge gas channels 11A and 11B via the channels 330b and 330c, respectively. In this case, the time required for activation can be shortened.

  Moreover, in this Embodiment, the structure provided with two modules was illustrated as a some module. The present invention is not limited to this. Since a plurality of modules can be started by one start-up reactor 330, a configuration including three or more modules can be employed.

[6. Sixth embodiment]
With reference to FIG. 6, the sixth embodiment of the ammonia production system and the ammonia production method according to the present invention will be described. The ammonia production 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 components as those in the above-described embodiment are denoted by the same reference numerals and the description thereof is omitted.

  The plurality of reactors 120a to 120c includes a first reactor 120a, a second reactor 120b, and a third reactor 120c arranged in series along the gas flow direction. The first reactor 120a is provided with a reaction part 121a, the second reactor 120b is provided with a reaction part 121ab, and the third reactor 120c is provided with a reaction part 121ac. As the catalyst provided in the reaction sections 121a, 121ab, and 121ac, the above-described ammonia synthesis catalyst can be suitably employed.

  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. It has been. The first reactor 120a has a flow path 12 through which purge gas heated by the first heat exchanger 10 is sent, and an intermediate product gas obtained in the first reactor 120a for sending to the first cooler 124a. A flow path 13 is provided. In the second reactor 120b, the 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 secondly supplied. A flow path 15 for sending to the cooler 124b is provided. In the third reactor 120c, the 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 in the third reactor 120c are supplied to the first heat. A flow path 17 for sending to the exchanger 10 is provided. That is, the plurality of reactors 120a to 120c has one reaction section 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 method according to the present invention will be described by explaining the operation function of the ammonia production system 1F having the above configuration.

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

  When starting up the ammonia production system 1F, the temperature of the purge gas downstream of the first heat exchanger 10 and upstream of the first reactor 120a is monitored. Thus, while monitoring the inlet temperature of the first reactor 120a, the opening / closing valve 111a is controlled to open / close when the purge gas is heated to, for example, 300 ° C. or more, so that the first reactor is discharged from the remaining purge gas channel 330af. The supply of the remaining purge gas to 120a and its flow rate are controlled. While controlling the flow rate of the purge gas, finally the on-off valve 111a is completely closed, and the operation shifts to the normal operation of the ammonia production system 1F.

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

[7. Seventh embodiment]
With reference to FIG. 7, a seventh embodiment of the ammonia production system and the ammonia production method according to the present invention will be described. The ammonia production increase system 1G shown in FIG. The same components as those in the above-described embodiment are denoted by the same reference numerals and the description thereof is omitted.

The flow path 311 is connected to the upstream side of the first heat exchanger 10 of the purge gas flow path 11 at one end, and is connected to the off-gas flow path 41 at the other end.
According to such a configuration, during operation of the ammonia production system 1G, a predetermined amount of purge gas is directly sent to the off-gas channel 41 via the channel 311, thereby supplying the purge gas to the reaction tower 20 and its Control the flow rate. In the ammonia production system including a quench type reactor, the flow rate of the gas in the quenching gas flow paths 26a and 26b is controlled to control the temperature of the reaction column 20, but when the quenching gas flow rate changes, the reaction column 20 is changed. The purge gas flow rate changes, and the temperature distribution of the reaction tower 20 changes. For this reason, stable control may not be possible. Therefore, the purge gas corresponding to the control range of the quenching gas flow rate is removed from the purge gas in the purge gas flow channel 11 from the flow channel 311, and the control of the reaction column 20 is facilitated by sending a constant flow of purge gas to the reaction column 20. Can do.

[8. Eighth embodiment]
With reference to FIG. 8, an eighth embodiment of the ammonia production system and the ammonia production method according to the present invention will be described. 8 further includes a flow meter 143 that measures an integrated flow rate of liquid ammonia. The same components as those in the above-described embodiment are denoted by the same reference numerals and the description thereof is omitted.
According to such a configuration, for example, when an ammonia production system of the above-described form is additionally installed as a module in an existing plant, it is possible to measure an ammonia production increase amount according to the newly installed equipment. Thereby, for example, it can be used for the accounting service according to the grasp of the increased ammonia production amount in module units or the increased production amount of the ammonia production system.

  In this specification, natural gas includes not only natural gas produced from gas fields, but also non-conventional natural gas such as shale gas and the like produced from oil fields accompanying oil. Is included. Natural gas as a raw material gas contains hydrocarbons of C2 or more in addition to methane, which is a main component of natural gas as a product gas.

  According to the ammonia production system and method according to the present invention, an ammonia production plant equipped with an ammonia synthesis loop can be easily installed by adding a necessary ammonia production system without requiring significant remodeling of the entire existing equipment. The amount of ammonia production can be changed and the production of ammonia can be started without affecting the operation of the existing plant.

1, 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H: Ammonia production system 10: First heat exchanger 11, 11A, 11B: Purge gas flow path 20: Reaction towers 21a, 21b, 21c, 121a, 121b 121ab, 121bb, 121ac: reaction sections 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)

In order to further produce ammonia using a purge gas purged from an ammonia production plant, an ammonia production system added to the ammonia production plant,
A first heat exchanger for heating purge gas purged from the ammonia production plant;
A plurality of reaction means arranged in series, wherein ammonia synthesis in the purge gas heated by the first heat exchanger is advanced to produce product gas;
Intermediate cooling means for cooling the intermediate product gas obtained between the plurality of reaction means;
A startup reactor for raising the temperature of the purge gas or the product gas;
A gas-liquid separator for separating ammonia from the product gas obtained by the plurality of reaction means,
The first heat exchanger is configured to heat-up the purge gas by exchanging heat between the purge gas and the product gas;
The start-up reactor raises the temperature of the purge gas upstream of the first heat exchanger and sends it to the purge gas downstream of the first heat exchanger or the product gas for heat exchange. The temperature of the product gas upstream of the exchanger is raised and sent to the product gas for heat exchange, or the temperature of the purge gas upstream of the first heat exchanger is raised and sent to the purge gas for heat exchange Configured to increase ammonia production.   The ammonia production system according to claim 1, wherein the start-up reactor is a reactor configured to raise the temperature of the purge gas or the product gas to 300 ° C or higher.   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. 2. The ammonia production system according to 2. The intermediate cooling means is a mixer for mixing the intermediate product gas with a coolant, a cooler for exchanging heat between the intermediate product 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 the cooler, a part of the purge gas, water, air, circulating refrigerant, Or the ammonia increase system as described in any one of Claims 1-3 which is these or a combination thereof. In order to further produce ammonia using a purge gas purged from an ammonia production plant, an ammonia production system added to the ammonia production plant,
A first heat exchanger for heating purge gas purged from the ammonia production plant;
A plurality of reaction means arranged in series, wherein ammonia synthesis in the purge gas heated by the first heat exchanger is advanced to produce product gas;
Intermediate cooling means for cooling the intermediate product gas obtained between the plurality of reaction means;
A start-up reactor for burning a portion of the purge gas upstream of the first heat exchanger;
A second heat exchanger for exchanging heat between the burned purge gas and the remaining purge gas;
A gas-liquid separator for separating ammonia from the product gas obtained by the plurality of reaction means,
The first heat exchanger is configured to heat-up the purge gas by exchanging heat between the purge gas and the product gas;
An ammonia augmentation system configured to raise the temperature of the purge gas upstream of the second heat exchanger and send it to the purge gas downstream of the first heat exchanger or the product gas for heat exchange.   The ammonia production system according to claim 5, wherein the start-up reactor and the second heat exchanger are a reactor and a heat exchanger configured to raise the temperature of the purge gas to 300 ° C or higher.   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. 6. The ammonia production system according to 6. The intermediate cooling means is a mixer for mixing the intermediate product gas with a coolant, a cooler for exchanging heat between the intermediate product 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, circulating refrigerant when the intermediate cooling means is the cooler. Or an ammonia production increase system according to any one of claims 5 to 7, which is a combination thereof.   An ammonia production increase system configured to control the supply and flow rate of purge gas after heat exchange in the second heat exchanger according to any one of claims 5 to 8. A plurality of ammonia production systems according to any one of claims 1 to 9 are provided as modules,
The off-gas from which the ammonia has been separated by the gas-liquid separator of the upstream module among the plurality of modules is supplied to the upstream or downstream module of the first heat exchanger or the ammonia recovery unit of the ammonia production plant. A system to increase ammonia production, which is sent to the factory. A flow path configured to send a purge gas upstream of the first heat exchanger to the downstream of the gas-liquid separator;
The plurality of reaction means are a plurality of reaction units provided in the one or more reaction towers;
11. The ammonia production system according to claim 1, wherein the flow rate of the purge gas in the flow path is controlled to make the purge gas flow rate to the one reaction tower constant.   The ammonia production-increasing system according to any one of claims 1 to 11, further comprising a flow meter for measuring the amount of the separated ammonia. A method for increasing ammonia production for further producing ammonia using purge gas purged from an ammonia production plant, comprising:
A heating step of heating the purge gas purged from the ammonia production plant using a first heat exchanger;
Using a plurality of reaction means arranged in series to advance ammonia synthesis in the heated purge gas into a product gas; and
An intermediate cooling step for cooling the intermediate product gas obtained between the plurality of reaction means;
A startup step of raising the temperature of the purge gas or the product gas to a predetermined temperature;
Separating ammonia from the product gas obtained by the plurality of reaction means,
In the heating step, the purge gas and the product gas are subjected to heat exchange to raise the temperature of the purge gas,
In the start-up step, the temperature of the purge gas before the heating step is raised, and the temperature of the product gas before the heat exchange, which is sent to the purge gas downstream of the first heat exchanger or the product gas for heat exchange, is raised. Ammonia sent to the product 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.   14. The method for increasing ammonia production according to claim 13, wherein the startup step is a reactor configured to raise the temperature of the purge gas or the product gas to 300 ° C. or higher.   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 includes mixing and cooling the intermediate product gas with a coolant, cooling by performing heat exchange between the intermediate product gas and the coolant using a cooler, 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 product gas with a coolant, and the intermediate product gas and the coolant are cooled using a cooler. The ammonia production 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 when the heat exchange is performed between the two and the cooling. . A method for increasing ammonia production for further production of ammonia using purge gas purged from an ammonia production plant, comprising:
A heating step of heating the purge gas purged from the ammonia production plant using a first heat exchanger;
Using a plurality of reaction means arranged in series to advance ammonia synthesis in the purge gas heated in the first heat exchange step to produce a product 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 portion of the purge gas upstream of the first heat exchanger;
A heat exchanging step of exchanging heat between the burned purge gas and the remaining purge gas using a second heat exchanger;
Gas-liquid separation step of separating ammonia from the product gas obtained by the plurality of reaction means,
In the heating step, the purge gas and the product gas are subjected to heat exchange to raise the temperature of the purge gas,
In the start-up step, the ammonia production system increases the temperature of the purge gas upstream of the second heat exchanger and sends it to the purge gas downstream of the first heat exchanger or the product gas for heat exchange.   The method for increasing ammonia production according to claim 17, wherein the startup reactor and the second heat exchanger are a reactor and a heat exchanger configured to raise the temperature of the purge gas to 300 ° C or higher.   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.   The ammonia production-increasing method which controls supply of the purge gas heated by the heat exchange in the said 2nd heat exchanger as described in any one of said 17-19, and its flow volume. A plurality of ammonia production systems according to any one of claims 1 to 12 are provided as modules,
The off-gas generated in the upstream module among the plurality of modules is purge gas used for the startup step in the upstream module, purge gas used for the heating step in the downstream module, or ammonia recovery in the ammonia production plant. Ammonia production method to be sent to the unit. After the start-up step, further comprising a flow rate adjustment step of sending the purge gas before the heating step to the downstream of the gas-liquid separator,
The plurality of reaction means are a plurality of reaction units 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 to the one reaction tower is made constant by controlling the flow rate of the purge gas in the flow path. .   The ammonia production-increasing method according to any one of claims 13 to 22, further comprising a flow rate measuring step for measuring the amount of the separated ammonia.

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