RU2726894C1 - Fertilizer production plant and method of producing fertilizer - Google Patents

Abstract

FIELD: agriculture.SUBSTANCE: inventions relate to agriculture. Plant for production of fertilizers, intended for production of urea-containing fertilizer from hydrocarbon source, wherein such plant for production of fertilizers contains: reforming unit, ammonia synthesis plant, urea synthesis plant, methanol synthesis plant, formaldehyde synthesis plant, urea formaldehyde composition production plant and fertilizer production plant. Method of producing urea-containing fertilizer from hydrocarbon source, wherein method includes: reforming step, ammonia synthesis step, a step for synthesis of urea, a step for synthesis of methanol, a step for synthesis of formaldehyde, a step for obtaining urea formaldehyde and a step for producing fertilizer.EFFECT: invention enables to obtain a fertilizer which has long-term action after application.9 cl, 14 dwg

Description

The technical field to which the invention relates

The present invention relates to an installation for the production of fertilizers and to a method for producing fertilizers.

State of the art

Urea is a compound containing a large amount of nitrogen and is therefore used as a fertilizer. A known technique suitable as a method for producing a fertilizer containing urea is disclosed in Patent Document 1. Patent Document 1 describes a production apparatus for producing urea using ammonia obtained from natural gas and carbon dioxide. In addition, Patent Document 1 discloses the use of the obtained urea as a fertilizer.

List of referenced documents

Patent sources.

Patent Document 1: JP2000-159519A (see in particular paragraph 0002 and Fig. 1).

Disclosure of invention

Solved problems

With regard to improving the convenience and ease of use of urea, it is preferable to obtain urea in granular form. In particular, granulated urea retains well in the soil after fertilization and is less likely to be washed away by rain or similar reasons. Thus, when using granular urea, it is possible to increase the duration of its action as a fertilizer.

In the process for granulating urea (ie, granulating) a granulating agent may be added to the urea. The granulating agent for urea can be, for example, a urea-formaldehyde formulation (eg, urea and formaldehyde dissolved in a solvent and converted to a liquid form). However, in the case of the plant disclosed in Patent Document 1, when a granulating agent is used in performing granulation, such a granulating agent must be supplied to the plant from the outside, resulting in additional costs for purchasing the granulating agent.

An object of at least one embodiment of the present invention is to provide a fertilizer production plant and a fertilizer production method suitable for the low cost production of a fertilizer with a long lasting effect after application.

Solution to the problem

(1) According to at least some embodiments of the present invention, a fertilizer production plant for producing a urea-containing fertilizer from a hydrocarbon source comprises: a reformer for producing at least hydrogen and a carbon source gas by reforming the hydrocarbon source; an ammonia synthesis unit for producing ammonia using at least a nitrogen and hydrogen source gas produced in a reformer; a urea synthesis unit for producing urea using at least a carbon source gas obtained from a reformer and ammonia obtained from an ammonia synthesis unit; a methanol synthesis unit for producing methanol using at least hydrogen from the reformer and a carbon source gas from the reformer; a formaldehyde synthesis unit designed to produce formaldehyde by oxidizing methanol obtained at a methanol synthesis unit; an installation for the production of a urea-formaldehyde composition, designed to obtain a urea-formaldehyde composition using at least urea obtained at a urea synthesis unit and formaldehyde obtained at a formaldehyde synthesis unit; and a fertilizer production unit for producing a fertilizer using at least urea obtained from a urea synthesis unit and a urea-formaldehyde composition obtained from a urea-formaldehyde composition production unit.

According to the configuration (1), it is possible to obtain both urea and urea-formaldehyde composition from a hydrocarbon source such as natural gas and coal in the same fertilizer production plant. Accordingly, there is no need for a separate external supply of a granulating agent, and it is possible to use the obtained urea-formaldehyde composition as a granulating agent for granulating urea. Granulated urea after its introduction into the soil has a long-term effect. Thus, according to one embodiment of the present invention, it is possible to obtain a fertilizer at low cost that has a long-lasting effect after application.

(2) In some embodiments, in the above configuration (1), the methanol synthesis unit is configured to produce methanol using excess hydrogen from the ammonia synthesis unit.

With the above configuration (2), it is possible to produce methanol by using excess hydrogen contained in the unreacted gas after ammonia production and a carbon source gas such as carbon dioxide. Thus, it is possible to fully utilize all of the hydrogen produced by reforming the hydrocarbon source in the reformer without generating waste.

(3) In some embodiments, in the above configuration (1) or (2), the methanol synthesis unit is configured to produce methanol using a carbon source gas obtained from the reformer.

With the above configuration (3), it is possible to produce methanol by using a carbon source gas (carbon dioxide) obtained from a reformer. Thus, it is possible to obtain methanol without supplying the carbon source gas from the outside.

(4) In some embodiments, in any of the above configurations (1) to (3), the ammonia synthesis unit comprises an ammonia synthesis unit for producing ammonia using at least a nitrogen and hydrogen source gas from a reformer, and a hydrogen recovery device for recovering excess hydrogen from an ammonia synthesis device. The methanol synthesis unit is configured to produce methanol using hydrogen recovered using such a hydrogen recovery device.

With the above configuration (4), it is possible to produce methanol by using a gas that is discharged from the hydrogen recovery apparatus and which contains a large volume of hydrogen (i.e., a gas with high hydrogen purity). Thus, it is possible to increase the yield of methanol.

(5) In some embodiments, in any of the above configurations (1) to (3), the ammonia synthesis unit comprises an ammonia synthesis unit for producing ammonia using at least a nitrogen and hydrogen source gas from a reformer, and a hydrogen recovery device for recovering excess hydrogen from an ammonia synthesis device. The methanol synthesis unit is configured to produce methanol using hydrogen taken between the ammonia synthesis unit and the hydrogen recovery unit.

With the above configuration (5), by using excess hydrogen having a maintained outlet pressure branching between the ammonia synthesis device and the hydrogen recovery device, it is possible to supply the methanol synthesis plant with high pressure hydrogen. Thus, there is no need to provide a compressor on the upstream side of the methanol synthesis plant for compressing the feed gas containing hydrogen.

(6) In some embodiments, in any of the above configurations (1) to (3), the ammonia synthesis unit includes an ammonia synthesis unit for producing ammonia using at least a nitrogen and hydrogen source gas from a reformer, and the methanol synthesis unit is configured to produce methanol using hydrogen obtained from the side downstream of the ammonia synthesis unit.

With the above configuration (6), in cases where there is no pressure relief device such as a hydrogen recovery device on the downstream side of the ammonia synthesis device, it is possible to use excess hydrogen, the outlet pressure of which is maintained. Accordingly, it is possible to supply the methanol synthesis plant with high pressure hydrogen. Thus, there is no need to provide a compressor on the upstream side of the methanol synthesis plant for compressing the feed gas containing hydrogen.

(7) In some embodiments, in any of the above configurations (1) to (6), an ammonia synthesis unit comprises: an ammonia synthesis unit for producing ammonia using at least a nitrogen and hydrogen source gas obtained from a reformer; and a compressor for compressing a feed gas that contains hydrogen and a nitrogen source gas to be introduced into the ammonia synthesis apparatus. The methanol synthesis unit is configured to produce methanol using hydrogen contained in the feed gas compressed by a compressor.

With the above configuration (7), by using the hydrogen contained in the feed gas compressed by the compressor, it is possible to supply the methanol synthesis plant with high pressure hydrogen. Thus, there is no need to provide a compressor on the upstream side of the methanol synthesis plant for compressing the feed gas containing hydrogen. In addition, the concentration of hydrogen and the concentration of nitrogen in the feed gas to be introduced into the ammonia synthesis apparatus are high, while the concentrations of other components are low. Thus, when producing methanol using a gas having a relatively high hydrogen concentration and a relatively high nitrogen concentration with relatively low concentrations of other components, it is possible to increase the partial pressure of hydrogen and nitrogen and improve the yield of methanol.

(8) In some embodiments, in any of the above configurations (1) to (7), the methanol synthesis unit is configured to produce methanol using reformer hydrogen, such hydrogen being on the upstream side of the unit ammonia synthesis, urea synthesis unit and methanol synthesis unit.

With the above configuration (8), it is possible to produce methanol by using reformer hydrogen. Thus, there is no need for a separate supply of the methanol synthesis plant with a carbon source gas and it becomes possible to simplify the piping system.

(9) According to at least some embodiments of the present invention, a method for producing a urea-containing fertilizer from a hydrocarbon source includes: a reforming step for reforming a hydrocarbon source of at least hydrogen and a carbon source gas; an ammonia synthesis step for producing ammonia using at least a nitrogen and hydrogen source gas obtained in the reforming step; a urea synthesis step for producing urea using at least the carbon source gas obtained in the reforming step and ammonia obtained in the ammonia synthesis step; a methanol synthesis step for producing methanol using at least hydrogen obtained in the reforming step and a carbon source gas obtained in the reforming step; a formaldehyde synthesis stage for producing formaldehyde by oxidizing methanol obtained in the methanol synthesis stage; a stage of obtaining a urea-formaldehyde composition, designed to obtain a urea-formaldehyde composition using at least urea obtained at the stage of urea synthesis, and formaldehyde obtained at the stage of formaldehyde synthesis; and a fertilizer production step for producing a fertilizer using at least the urea obtained in the urea synthesis step and the urea-formaldehyde composition obtained in the urea-formaldehyde composition preparation step.

According to the above configuration (9), it is possible to obtain both urea and urea-formaldehyde composition from a hydrocarbon source such as natural gas in the same fertilizer production plant. Accordingly, there is no need for a separate external supply of a granulating agent, and it is possible to use the obtained urea-formaldehyde composition as a granulating agent for granulating urea. Granular urea after its introduction has a long-term effect. Thus, according to one embodiment of the present invention, it is possible to obtain a fertilizer at low cost that has a long-lasting effect after application.

Useful effect

An object of at least one embodiment of the present invention is to provide a fertilizer production plant and a fertilizer production method suitable for the low cost production of a fertilizer that has a long lasting effect after application.

Brief Description of Drawings

FIG. 1 is a system diagram of a fertilizer plant according to a first embodiment of the present invention.

FIG. 2 shows a schematic diagram of a methanol synthesis plant from the fertilizer plant of FIG. 1.

FIG. 3 is a schematic diagram of a methanol synthesis plant from the fertilizer plant of FIG. 1, where a single reactor other than the one shown in FIG. 2.

FIG. 4 is a schematic diagram of a methanol synthesis plant from the fertilizer plant of FIG. 1, where a plurality of reactors other than the one shown in FIG. 2.

FIG. 5 is a flowchart showing a fertilizer production method implemented in the fertilizer plant of FIG. 1.

FIG. 6 is a system diagram of a fertilizer plant according to a second embodiment of the present invention.

FIG. 7 is a system diagram of a fertilizer plant according to a third embodiment of the present invention.

FIG. 8 is a schematic diagram of a methanol synthesis plant from the fertilizer plant of FIG. 7.

FIG. 9 is a schematic diagram of another methanol synthesis plant from the fertilizer plant of FIG. 7.

FIG. 10 is a schematic diagram of another methanol synthesis plant from the fertilizer plant of FIG. 7.

FIG. 11 is a schematic diagram of another methanol synthesis plant from the fertilizer plant of FIG. 7.

FIG. 12 is a system diagram of a fertilizer plant according to a fourth embodiment of the present invention.

FIG. 13 is a system diagram of a fertilizer plant according to a fifth embodiment of the present invention.

FIG. 14 is a system diagram of a fertilizer plant according to a sixth embodiment of the present invention.

Implementation of the invention

In the following, embodiments of the present invention are described in detail with reference to the accompanying drawings. However, the descriptions and drawings disclosed as embodiments are for illustrative purposes only and may be suitably modified without departing from the scope of the present invention. In addition to the above, two or more embodiments may be carried out in combination.

It is understood, however, that unless specifically indicated otherwise, all dimensions, materials, shapes, relative positions and other similar features of the components described in the embodiments are to be interpreted as illustrative only and not intended to limit the scope of the present invention.

For example, expressions referring to relative or absolute position, such as “toward”, “toward”, “parallel”, “orthogonal”, “centered”, “concentric” and “coaxial”, should not be construed as merely indicating location. in its literal and strict meaning, but also includes states where such an arrangement is relatively offset by tolerances, or angles, or distances at which it is possible to achieve the same function.

For example, expressions of equal state such as "same", "equal" and "same" should not be construed only as an indication of a state in which certain features are strictly equal, but also include a state in which there is a tolerance or difference. which nevertheless allow you to achieve the same function.

In addition, expressions concerning, for example, a shape such as a rectangular shape or a cylindrical shape should not be considered only in relation to a geometrically strict shape, but also includes a shape with roughness or with rounded corners within boundaries, within which it remains possible to achieve the same effect.

On the other hand, expressions such as “contains,” “includes,” “has,” “comprises,” and “comprises,” are not intended to be exclusive of other components.

FIG. 1 is a system diagram of a fertilizer production plant 100 according to a first embodiment of the present invention. Fertilizer plant 100 is designed to produce a fertilizer that contains urea (urea fertilizer) from a hydrocarbon source such as natural gas and coal. FIG. 1, natural gas is given as a source of hydrocarbons. Installation 100 for the production of fertilizers includes a reformer 1 as a reforming unit, an ammonia synthesis unit 10, a urea synthesis unit 20, a methanol synthesis unit 30, a formaldehyde synthesis unit 40, a mixer 51 as a unit for the production of a urea-formaldehyde composition, and a granulating unit 61 in the quality of the fertilizer production unit. In addition, according to one embodiment of the present invention, the fertilizer plant 100 further includes a conversion reactor 2, a carbon dioxide recovery unit 3, and a methanization unit 4 on the downstream side of the reformer 1.

The reformer 1 is designed to produce at least hydrogen and carbon dioxide (carbon source gas) using air and steam and to reform natural gas that contains methane. The reformer 1 includes, although not shown, a primary reformer that performs a steam reforming reaction and a secondary reformer that performs a partial oxidative reforming reaction and a steam reforming reaction. The reaction equations for the primary reformer and the secondary reformer are more specifically set forth below.

(a) Primary reformer (steam reforming reaction)

(b) Secondary reformer (partial oxidative reforming reaction and steam reforming reaction)

Accordingly, in the reformer 1, carbon dioxide is produced from natural gas containing methane. However, with respect to the portion of carbon monoxide formed by the reactions of equations (1) and (3), the reaction of equation (2) does not develop further and the product remains in the form of carbon monoxide. The remaining carbon monoxide is converted to carbon dioxide in the conversion reactor 2 at a later stage.

The reactions shown in equations (1) and (2) can be performed using one or another reforming catalyst. As a reforming catalyst, for example, an oxidized transition metal such as nickel and platinum can be used. The reaction conditions can be, for example, from about 900 ° C to 1000 ° C and from 2.5 MPa to 3.5 MPa at the outlet of the catalyst bed located in the secondary reformer.

As mentioned above, the reformer 1 also consumes air. Thus, the gas exiting the reformer 1 and fed at a later stage to the conversion reactor 2 contains components originating from air. More specifically, the gas exiting the reformer 1 contains a nitrogen source gas such as nitrogen (a gas that serves as a starting material in the synthesis of ammonia).

The conversion reactor 2 is designed to produce carbon dioxide and hydrogen by converting carbon monoxide and water vapor in the gas coming from the reformer 1. Thus, in the conversion reactor 2, the concentration of carbon monoxide in the gas decreases and instead the concentration of carbon dioxide increases. By converting carbon monoxide to carbon dioxide, it is possible to recover the carbon derived from carbon monoxide as carbon dioxide by the carbon dioxide recovery device 3 at a later stage.

In the reactor 2 conversion, a chemical reaction occurs, represented by the following equation (4).

As a catalyst for the conversion of carbon monoxide (conversion catalyst), one or another conversion catalyst can be used. The conversion catalyst can be, for example, a copper-zinc catalyst. The reaction conditions can be, for example, from about 200 ° C to 450 ° C and from 2.5 MPa to 3.5 MPa at the outlet of the catalyst bed disposed in the conversion reactor 2.

The carbon dioxide extraction device 3 is designed to extract and remove carbon dioxide from the gas. By removing carbon dioxide from the gas, it is possible to prevent the entry of carbon dioxide into the ammonia synthesis device 12 at a later stage and to reduce its effect on the ammonium generation catalyst (described below). Extraction of carbon dioxide by means of the carbon dioxide extraction device 3 is possible, for example, by bringing the gas into contact with an alkaline solution. Then, the recovered carbon dioxide is separated from the alkaline solution, for example by heating such an alkaline solution, and supplied to the urea synthesis unit 20 and methanol synthesis unit 30 described below.

The methanization device 4 is designed to convert all of the carbon dioxide remaining after the recovery by the carbon dioxide recovery unit 3 and the carbon monoxide not converted to carbon dioxide by the conversion reactor 2 and remaining unrecovered by the carbon dioxide recovery unit 3 into methane. The methanizer 4 removes oxidized carbon (carbon monoxide) such as carbon monoxide and carbon dioxide, and thus inhibits the oxidized carbon from entering the ammonia synthesis device 12 at a later stage. Accordingly, it is possible to suppress the effect of oxidized carbon on the ammonia generation catalyst (described below).

In the methanization device 4, chemical reactions described by the following equations (5) and (6) take place.

As a catalyst for producing methane (methanization catalyst), one or another methanization catalyst can be used. The methanization catalyst can be, for example, a nickel catalyst. The reaction conditions can be, for example, about 250 ° C to 350 ° C and from 2.0 MPa to 3.0 MPa at the outlet of the catalyst bed located in the methanization unit 4.

The ammonia synthesis unit 10 is designed to produce ammonia using at least hydrogen obtained by the reformer 1 (reformer unit) and nitrogen (nitrogen source gas) in the air introduced by the reformer 1.

The ammonia synthesis unit 10 includes a compressor 11, an ammonia synthesis unit 12, an ammonia recovery unit 13 and a hydrogen recovery unit 14.

Compressor 11 is designed to compress the feed gas (containing hydrogen and nitrogen, as well as methane as an impurity) for introduction into the ammonia synthesis device 12 at a later stage. In the high pressure ammonia synthesis device 12, an ammonia formation reaction takes place. Thus, by increasing the pressure of the feed gas with the compressor 11, it is possible to accelerate the ammonia formation reaction.

The ammonia synthesis device 12 is designed to produce ammonia using at least hydrogen and nitrogen in the feed gas. Thus, the device 12 for the synthesis of ammonia is designed to produce ammonia using at least hydrogen obtained by the reformer 1 (reformer) and nitrogen (nitrogen source gas) in the air introduced by the reformer 1. The obtained ammonia, in the form of a liquid phase, is supplied to the below-described urea synthesis unit 20 through the ammonia supply system 71. On the other hand, the gas phase (purge gas) from the ammonia synthesis apparatus 12 is supplied to an ammonia recovery apparatus 13 described below. The gas phase of the ammonia synthesis apparatus 12 contains excess hydrogen and nitrogen (unreacted nitrogen) as well as unreacted methane.

In the ammonia synthesis apparatus 12, a chemical reaction occurs as illustrated by the following equation (7).

As a catalyst for the production of ammonia (catalyst for the formation of ammonia), one or another catalyst for the formation of ammonia can be used. The catalyst for the formation of ammonia can be, for example, an iron catalyst, which contains, for example, ferric oxide (iron oxide (II, III)). The reaction conditions may be, for example, from about 400 ° C to 480 ° C and from 12 MPa to 20 MPa at the outlet of the catalyst bed located in the ammonia synthesis device 12.

The ammonia recovery unit 13 is designed to recover ammonia contained in the gas phase from the ammonia synthesis unit 12. The ammonia recovery device 13 includes a refrigeration device (not shown) adapted to cool the gas phase to a temperature of about 0 ° C. Accordingly, the ammonia in the gas phase is converted to liquid and the liquefied ammonia is recovered. Such recovered ammonia, similar to the liquid phase ammonia described above from the ammonia synthesis device 12, is fed through the ammonia supply system 71 to a urea synthesis unit 20 described below.

The hydrogen recovery device 14 is designed to recover excess hydrogen from the ammonia synthesis device 12. The excess hydrogen recovered by the hydrogen recovery unit 14 is returned between the methanization unit 4 and the compressor 11 through the hydrogen circulation system 72 (upstream of the compressor 11). In this case, the recovered excess hydrogen is also sent to the methanol synthesis unit 30 through a hydrogen supply system 73, which is branched halfway from the hydrogen circulation system 72. In addition, the entire amount of hydrogen recovered by the hydrogen recovery unit 14 can be supplied to the methanol synthesis unit 30. On the other hand, the residual (unconverted) hydrogen and residual (unconverted) methane are directed to the reformer 1 or to a boiler not shown (or both) with residual (unconverted) nitrogen and are used as fuel for combustion.

The hydrogen recovery device 14 may be of any design as long as it is suitable for hydrogen recovery. More specifically, the hydrogen recovery apparatus 14 may be configured to use a hydrogen separation membrane for recovering hydrogen from a gas.

The urea synthesis unit 20 is designed to produce urea using at least a carbon source gas such as carbon dioxide or the like produced by the reformer 1 (reformer) and ammonia produced by the ammonia synthesis unit 10. The carbon dioxide used by the urea synthesis unit 20 is carbon dioxide recovered by the above-described carbon dioxide recovery unit 3. In addition, the ammonia used by the urea synthesis unit 20 is ammonia that is produced in the above-described ammonia synthesis unit and supplied through the ammonia supply system 71.

The urea synthesis unit 20 includes a compressor 21 and a urea synthesis device 22.

The compressor 21 is designed to compress the carbon dioxide introduced into the urea synthesis device 22 at a later stage. In the urea synthesis device 22, the urea formation reaction is carried out under high pressure. Thus, by increasing the pressure of the feed gas with the compressor 21, it is possible to accelerate the urea production reaction. The resulting urea is fed to a mixer 51 described below (installation for the production of urea-formaldehyde composition) and to a granulation device 61 (installation for the production of fertilizer).

The urea synthesis device 22 is designed to produce urea by reacting carbon dioxide and ammonia in the feed gas. The urea produced is in the form of a liquid. The urea synthesis device 22 is supplied not only with carbon dioxide compressed by the above-described compressor 21, but also with ammonia recovered by the above-described ammonia recovery device 13 and a compressed compressor (high pressure pump) 80. In the urea synthesis device 22, a chemical reaction occurs, illustrated by the following equation (8).

Although not particularly limited, the conditions for the production of urea can be approximately, for example, from 170 ° C to 200 ° C and from 13 MPa to 18 MPa at the outlet of the urea synthesis device 22.

The methanol synthesis unit 30 is designed to produce methanol by using at least hydrogen obtained by the reformer 1 (reformer) and a carbon source gas such as carbon dioxide obtained by the reformer 1. Carbon dioxide used in the methanol synthesis unit 30, is carbon dioxide obtained by the reformer 1 (reformer) and recovered by the above-described carbon dioxide recovery unit 3. Accordingly, the production of methanol using carbon dioxide obtained from the reformer 1 allows methanol to be produced without an external supply of carbon dioxide.

In addition, the hydrogen used in the methanol synthesis unit 30 is excess hydrogen in the aforementioned ammonia synthesis unit 10, which is recovered by the above-described hydrogen recovery unit 14 and supplied through the hydrogen circulation system 72 and the hydrogen supply system 73. As described above, by producing methanol using excess hydrogen contained in the unreacted gas during the formation of ammonia, it is possible to achieve full utilization of the hydrogen obtained by reforming the hydrocarbon feed in the reformer 1 without generating waste. In particular, in the production of methanol using hydrogen recovered by the hydrogen recovery apparatus 14, it is possible to produce methanol using a gas that contains a large volume of hydrogen (i.e., a gas with high hydrogen purity). Thus, it is possible to increase the yield of methanol.

The methanol synthesis unit 30 includes a compressor 31, a methanol synthesis unit 32 and a circulation compressor 33.

The compressor 31 is designed to compress the hydrogen introduced into the methanol synthesis unit 32 at a later stage. At the outlet of the compressor 31, carbon dioxide, partially removed from the outlet of the compressor 21, is directed to the feed and mixed with hydrogen compressed by the compressor 31. In cases where carbon dioxide cannot be used at the outlet of the compressor 21, the carbon dioxide recovered by the carbon dioxide recovery device 3 can be compressed compressor 31. In this case, compressor 31 compresses a gas mixture of carbon dioxide and hydrogen. In the methanol synthesis device 32, the methanol formation reaction takes place under high pressure. Thus, by increasing the hydrogen pressure with the compressor 31, it is possible to accelerate the methanol production reaction.

The methanol synthesis device 32 is designed to produce methanol by reacting carbon dioxide and hydrogen in a feed gas. In the methanol synthesis apparatus 32, a chemical reaction occurs as illustrated by the following equation (9).

As a catalyst for producing methanol (described below, methanol synthesis catalyst 32b1 shown in Fig. 2), one or another methanol synthesis catalyst can be used. For example, it is possible to use the catalyst disclosed in JPH7-8799A as a methanol synthesis catalyst. In addition, the reaction conditions can be, for example, from 220 ° C to 270 ° C and from 7 MPa to 12 MPa.

As indicated above, in the methanol synthesis apparatus 32, 1 mol of carbon dioxide is reacted with 3 mol of hydrogen. Thus, it is desirable to set the ratio of the amount of carbon dioxide supplied from the carbon dioxide recovery device 3 to the amount of hydrogen supplied from the hydrogen recovery device 14 through the hydrogen circulation system 72 equal to 1: 3. In addition, the amount of carbon dioxide supplied from the carbon dioxide recovery unit 3 to the methanol synthesis unit 32 is controlled by adjusting the opening degree of a flow control valve (not shown) located in the system connecting the carbon dioxide recovery unit 3 and the compressor 31. In addition, , it is possible to control the amount of hydrogen supplied to the methanol synthesis device 32 by adjusting the opening degree of a flow control valve (not shown) located in the hydrogen supply system 73.

The circulating compressor 33 is designed to compress the unreacted feed gas exiting the methanol synthesis device 23 for recycling to the methanol synthesis device 23. This point is described in detail with reference to FIG. 2 - 4.

FIG. 2 is a schematic diagram of a methanol synthesis plant 30 from the fertilizer plant 100 of FIG. 1. As mentioned above, this methanol synthesis unit 30 includes a compressor 31, a methanol synthesis unit 32, and a circulation compressor 33. In addition to the above, the methanol synthesis unit 32 includes heat exchangers 32a, 32c, a shell-and-tube reactor 32b, and a separator 32d. The reactor 32b contains a methanol synthesis catalyst 32b1, which in FIG. 2 is illustrated with dotted strokes.

A gas mixture (feed gas) of hydrogen compressed by compressor 31 and carbon dioxide compressed by compressor 21 (see FIG. 1) receives heat from the reaction gas exiting the reactor 32b and is heated in heat exchanger 32a. Further, the gas mixture of hydrogen and carbon dioxide heated in the heat exchanger 32a is fed to the reactor 32b, inside of which the methanol formation reaction takes place. At this time, a medium to be cooled (eg, pressurized boiling water, air, or feed gas before being introduced into the reactor 32b) is passed through the interior of the reactor 32b. In addition, since the gas flowing through the methanol synthesis catalyst 32b1 in the reactor 32b is cooled, the methanol production reaction, which is exothermic, is accelerated. In addition, the reaction gas after the methanol formation reaction (containing unreacted hydrogen and carbon dioxide, and methanol gas) in the heat exchanger 32a gives off heat to the gas mixture and is cooled by the heat exchanger 32c through which cooling water flows (not shown).

When the reaction gas is cooled in the heat exchanger 32c, the methanol gas is converted to a liquid. Thus, liquid methanol is recovered from the bottom of the separator 32d, which is located at a later stage than the heat exchanger 32c. On the other hand, from the top of the separator 32d, unreacted hydrogen and carbon dioxide are recovered as a purge gas. A portion of the purge gas is then compressed by the circulation compressor 33 and then returned to the downstream side of the compressor 31. In addition, the remainder of the purge gas is supplied to the reformer 1 or to a boiler not shown through the exhaust system 75 to avoid condensation of the components inert gas (nitrogen, methane), in order to be used as fuel in combustion. Accordingly, by circulating unreacted hydrogen and carbon dioxide through the circulating compressor 33, it is possible to improve the methanol yield.

FIG. 3 is a schematic diagram of a methanol synthesis plant 30 from the fertilizer plant 100 of FIG. 1, where a single reactor 32f different from the reactor 32b shown in FIG. 2. Reactor 32f is an adiabatic reactor which, in contrast to the above-described reactor 32b, has a simple structure designed only to be filled with methanol synthesis catalyst 32b1.

In the reactor 32f, the vessel 32f1 accommodates a methanol synthesis catalyst 32b1 of the same type as the catalyst disposed in the above-described reactor 32b. In addition, unlike the aforementioned reactor 32b, the reactor 32f is not provided with cooling air. Thus, the reactor 32f does not undergo cooling using cooling air (ie, natural cooling only). As a result, the reactor 32f has a simpler structure than the above-mentioned reactor 32b.

In the example illustrated in FIG. 3, the heat released during the methanol synthesis reaction is not removed. Thus, when a feed gas flow passes through the interior of the methanol synthesis catalyst 32b1, the temperature rises. However, the equilibrium conversion rate in the methanol synthesis reaction using carbon dioxide and hydrogen is not high, and thus the temperature rise accompanying the adiabatic reaction is small. Therefore, in addition to the one shown in FIG. 2 of a shell-and-tube type reactor 32b with high heat dissipation efficiency, it is also possible to use the reactor 32f shown in FIG. 3.

FIG. 4 is a schematic diagram of a methanol synthesis plant 30 from a fertilizer plant 100 shown in FIG. 1, where a plurality of reactors 32f other than the reactor 32b shown in FIG. 2. In the example shown in FIG. 4, two reactors 32f (adiabatic reactors) are connected in series. Accordingly, by using multiple reactors 32f, it is possible to increase the methanol yield.

In addition, a heat exchanger 32k is provided between the upstream reactor 32f and the downstream reactor 32f for cooling the gas (containing methanol gas) emanating from the upstream reactor 32f. The heat exchanger 32k is designed to cool the gas to such an extent that the methanol gas is not yet liquefied, unlike the heat exchanger 32c described above. In addition, by cooling the gas exiting the upstream reactor 32f using the heat exchanger 32k, it is possible to accelerate the methanol synthesis reaction in the downstream reactor 32f.

Referring again to FIG. 1, a formaldehyde synthesis unit 40 is designed to produce formaldehyde by oxidizing methanol obtained from a methanol synthesis unit 30. Formaldehyde synthesis unit 40 produces formaldehyde for mixing with urea obtained from urea synthesis unit 20.

Installation 40 synthesis of formaldehyde 40 includes an oxidation reactor 41 and an absorber 42.

The oxidizing reactor 41 is designed for the oxidation of methanol obtained in the unit 30 for the synthesis of methanol. Oxidation is performed using air. Oxidation of methanol leads to the production of formaldehyde. The resulting formaldehyde is a gas, and the formaldehyde gas at a later stage is fed to the absorber 42.

In the oxidation reactor 41, a chemical reaction occurs, represented by the following equation (10).

Oxidation of methanol can be carried out, for example, by an excess air process. More specifically, methanol can be oxidized, for example, using a metal oxide such as vanadium, molybdenum and iron, under conditions of about 240 ° C to 300 ° C and from 0.1 MPa to 0.6 MPa.

The absorber 42 is designed to spray water onto the formaldehyde produced by the oxidation reactor 41 and to cause the formaldehyde to be absorbed (dissolved) by the water. The dissolved formaldehyde water is fed to a later stage mixer 51.

The mixer 51 (unit for producing urea-formaldehyde composition) is designed to obtain a urea-formaldehyde composition using at least urea obtained in unit 20 for urea synthesis and formaldehyde obtained in unit 40 for formaldehyde synthesis. In the mixer 51, a urea-formaldehyde composition is obtained by mixing urea and formaldehyde. The resulting urea-formaldehyde composition in one embodiment of the present invention is used as a granulating agent for urea.

The component ratio of urea and formaldehyde is not specifically limited. For example, in 100 parts by weight of a urea-formaldehyde composition, urea can be 20 to 30 parts by weight, formaldehyde can be 50 to 60 parts by weight, and the rest can be water. The water used herein can be the water used by the absorber 42 or fresh water entering the mixer 51. When the water used in the absorber 42 is used in the urea-formaldehyde preparation unit, water that is discharged from the absorber 42 and contains formaldehyde (formaldehyde solution) can be mixed with the urea.

However, the specific structure of the mixer 51 is not particularly limited.

The granulating device 61 (fertilizer production unit) is designed to obtain a granular fertilizer using at least a urea solution obtained in a urea synthesis unit 20 and a urea-formaldehyde composition obtained in a mixer 51, which serves as an installation for the production of a urea-formaldehyde composition. The formaldehyde contained in the urea-formaldehyde composition acts as a binding agent, and the urea from the urea synthesis unit 20 is granulated. Granular urea obtained from the granulation process is sent to the shipment and used as fertilizer.

While the particle size of the granular urea is not particularly limited, the particle diameter may be, for example, 2 mm to 6 mm.

In addition, a control device, not shown in the drawings, is used to monitor the operation of the fertilizer plant 100. Although not shown, such a control device includes a central processing unit (CPU), random access memory (RAM), read only memory (ROM), a hard disk drive (HDD ), control circuit, etc., and is implemented when the CPU executes a predetermined program stored in ROM.

With the above-configured fertilizer plant 100, it is possible to produce both urea and urea-formaldehyde composition from a hydrocarbon source such as natural gas and coal within the same fertilizer plant. Accordingly, there is no need for a separate external supply of a granulating agent, and it is possible to use the obtained urea-formaldehyde composition as a granulating agent for granulating urea. Granular urea after its introduction has a long-term effect. Thus, according to one embodiment of the present invention, it is possible to obtain a fertilizer at low cost that has a long-lasting effect after application.

FIG. 5 is a flowchart showing a fertilizer production method performed in the fertilizer plant 100 of FIG. 1. The block diagram of FIG. 3 is performed using the above-mentioned control device. The block diagram in FIG. 3 illustrates an example of a method for producing a fertilizer according to one embodiment of the present invention, that is, a method for producing a urea-containing fertilizer from a hydrocarbon source. More specifically, as shown in FIG. 3, urea is produced in steps S1 to S3, and a urea-formaldehyde composition is produced in steps S4 through S6. In addition, at stage S7, fertilization is made from urea and urea-formaldehyde composition. However, the method for producing fertilizer according to one embodiment of the present invention does not have to be performed in the order of the steps shown in FIG. 3. A number of stages can be performed simultaneously, or the order of the stages can be changed.

A fertilizer production method according to one embodiment of the present invention includes a reforming step S1, an ammonia synthesis step S2, a urea synthesis step S3, a methanol synthesis step S4, a formaldehyde synthesis step S5, a urea-formaldehyde composition preparation step S6, and a fertilizer production step S7.

The reforming step S1 is for producing hydrogen and carbon dioxide (carbon source gas) by reforming natural gas (hydrocarbon source). The reforming stage S1 is performed by the above-described reformer 1 (reformer).

The ammonia synthesis step S2 is designed to produce ammonia using at least the hydrogen obtained from the reforming step S1 and nitrogen (nitrogen source gas). The ammonia synthesis step S2 is performed in the above-described ammonia synthesis unit 10.

The urea synthesis step S3 is intended to produce urea using at least carbon dioxide (carbon source gas) obtained in the reforming step S1 and ammonia obtained in the ammonia synthesis step S2. The urea synthesis step S2 is carried out in the above-described urea synthesis unit 20.

The methanol synthesis step S4 is intended to produce methanol using at least hydrogen obtained in the reforming step S1 and carbon dioxide (carbon source gas) obtained in the reforming step S1. The methanol synthesis step S4 is carried out in the above-described methanol synthesis unit 30.

The formaldehyde synthesis step S5 is intended to produce formaldehyde by oxidizing the methanol obtained in the methanol synthesis step S4. The formaldehyde synthesis step S5 is performed by the above-described formaldehyde synthesis apparatus 40.

The step S6 for the preparation of the urea-formaldehyde composition is intended for the preparation of the urea-formaldehyde composition using at least the urea obtained in the urea synthesis step S3 and the formaldehyde obtained in the formaldehyde synthesis step S5. The step S6 for producing the urea-formaldehyde composition is performed by the above-described mixer 51 (urea-formaldehyde composition production unit).

The fertilizer production step S7 is designed to produce a granular fertilizer using at least the urea solution obtained in the urea synthesis step S3 and the urea-formaldehyde composition obtained in the urea-formaldehyde composition production step S6. The fertilizer production step S7 is performed on the above-described granulating device 61 (fertilizer production unit).

According to the above fertilizer production method including the above steps, it is possible to obtain both urea and urea-formaldehyde composition from a hydrocarbon source such as natural gas and coal within the same fertilizer production plant 100. Accordingly, there is no need for a separate external supply of a granulating agent, and it is possible to use the obtained urea-formaldehyde mixture as a granulating agent for granulating urea. Granular urea after its introduction has a long-term effect. Thus, according to one embodiment of the present invention, it is possible to produce a fertilizer that has a long-lasting effect after application at low cost.

FIG. 6 is a system diagram of a fertilizer production plant 101 according to a second embodiment of the present invention. In the following description (which refers not only to Fig. 6, but also to Fig. 7 and the following drawings), the same reference numerals refer to the same features of the above-described fertilizer production plant 100 (Fig. 1 ) and are no longer described again, while the description mainly deals with the differences from the plant 100 for the production of fertilizers.

In the above-described fertilizer production plant 100, hydrogen recovered by the hydrogen recovery device 14 (which contains high purity hydrogen) is returned to the upstream side of the compressor 11 through the hydrogen circulation system 72. In addition, a portion of the hydrogen that flows through the hydrogen circulation system 72 (or, as described above, all of the hydrogen) is directed to the compressor 31 of the methanol synthesis unit 30 via the hydrogen supply system 73.

In the described, illustrated FIG. 6 to the fertilizer plant 101, the hydrogen recovered by the hydrogen recovery device 14 is returned to the upstream side of the compressor 11 through the hydrogen circulation system 72. However, the hydrogen circulation system 72 is configured to return the entire amount of hydrogen recovered by the hydrogen recovery device 14 to the side upstream of the compressor 11. In addition, a hydrogen supply system 74 is provided separately from the hydrogen circulation system 72 for supplying the device 32 methanol synthesis with hydrogen taken between the hydrogen recovery unit 14 and the ammonia synthesis unit 12 (more specifically, between the hydrogen recovery unit 14 and the ammonia recovery unit 13). Thus, the methanol synthesis unit 30 produces methanol using at least a portion of the hydrogen withdrawn between the ammonia synthesis unit 12 and the hydrogen recovery unit 14.

On both the downstream side of the ammonia synthesis unit 12 and the downstream side of the ammonia recovery unit 13, that is, on the side upstream of the hydrogen recovery unit 14, the gas pressure is relatively high, and thus the unit 12 Ammonia Synthesis Ammonia is produced under high pressure. Thus, by using at least a portion of the excess hydrogen, which has a maintained outlet pressure through the hydrogen supply system 74 connected to the ammonia synthesis device 12 and the hydrogen recovery device 14, it is possible to supply the methanol synthesis unit 30 with high pressure hydrogen. Thus, there is no need to provide a compressor on the upstream side of the methanol synthesis unit 30 for compressing the feed gas containing hydrogen.

In addition, as in the above-described fertilizer plant 100, the amount of hydrogen supplied to the methanol synthesis device 32 can be controlled by adjusting the opening degree of a flow control valve (not shown) located in the hydrogen supply system 74.

FIG. 7 is a system diagram of a fertilizer production plant 102 according to a third embodiment of the present invention. In the aforementioned fertilizer plant, a hydrogen recovery apparatus 14 for recovering hydrogen from a gas is disposed on the downstream side of the ammonia recovery apparatus 13. However, shown in FIG. 7, the fertilizer plant 102 does not include a hydrogen recovery device 14 (a device designed to cause a pressure drop), and unreacted gas from the ammonia synthesis device 12 does not return to the upstream side of the compressor 11.

In addition, in the fertilizer production unit 102, a hydrogen supply system 76 associated with the methanol synthesis unit 30 is provided on the downstream side of the ammonia synthesis unit 12 and on the downstream side of the ammonia recovery unit 13. In addition, a portion of the high-pressure hydrogen downstream of the ammonia recovery unit 13 is fed through the hydrogen supply system 76 to the methanol synthesis unit 30. Thus, the methanol synthesis unit 30 produces methanol using at least a portion of the hydrogen downstream of the ammonia synthesis unit 12.

Accordingly, similarly to the aforementioned fertilizer plant 101 (see FIG. 6), in cases where a pressure relief device such as a hydrogen recovery device is not available on the downstream side of the ammonia synthesis device 12, at least part of excess hydrogen, which has a maintained outlet pressure. Accordingly, it is possible to supply the methanol synthesis unit 30 with high pressure hydrogen. Thus, there is no need to provide a compressor on the upstream side of the methanol synthesis unit 30 for compressing the feed gas containing hydrogen.

In addition, as in the above-described fertilizer plant 100, the amount of hydrogen supplied to the methanol synthesis device 32 can be controlled by adjusting the opening degree of a flow control valve (not shown) located in the hydrogen supply system 76.

In addition, in the plant 102 for the production of fertilizers, the plant 30 for methanol synthesis does not include a circulation compressor 33. This point is described in detail with reference to FIG. 8 and 9.

FIG. 8 is a schematic diagram of a methanol synthesis plant 30 in the fertilizer plant 102 of FIG. 7. In the methanol synthesis unit 30 of the fertilizer production unit 102, as well as in the fertilizer production unit 100 (see FIG. 2), a methanol synthesis device 32 is provided. However, the fertilizer plant 102 illustrated in FIG. 7 includes neither compressor 31 nor circulation compressor 33. Thus, unlike the methanol synthesis unit 30 shown in FIG. 2, the purge gas exiting the top of the separator 32d is supplied to the reformer 1 or a boiler not shown (or both) and is used as a combustion fuel. Accordingly, there is no need to provide the circulation compressor 33 as shown in FIG. 2, and it becomes possible to reduce power consumption.

In addition, as shown in FIG. 8, the gas does not circulate in the methanol synthesis device 32 and the reaction proceeds in a so-called "one pass". This is because the hydrogen does not return to the upstream side of the compressor 11 in the ammonia synthesis unit 10. Thus, in the fertilizer plant 102, unlike the above described fertilizer plants 100 and 101, the methanol synthesis device 32 is supplied with a large proportion of unreacted hydrogen from the ammonia synthesis device 12. Accordingly, it is possible to increase the amount of hydrogen present in the reaction system of the methanol synthesis unit 32 as compared with the above-described fertilizer units 100 and 101.

Here, methanol is produced according to the above reaction equation (9). Thus, when the amount of hydrogen present in the reaction system increases, the equilibrium of the reaction in the above equation (9) shifts to the right. As a result, the rate of methanol synthesis increases and it is possible to increase the production of methanol. Thus, it is possible to produce a sufficient amount of methanol even in cases where the circulation compressor 33 is not used and the reaction is carried out in a so-called "one pass".

FIG. 9 is a schematic diagram of another methanol synthesis plant 30 in the fertilizer plant 102 of FIG. 5. In the embodiment shown in FIG. 9 in the example instead of the reactor 32b from the example illustrated in FIG. 8, a reactor 32f (adiabatic reactor) similar to the reactor 32f described with reference to FIG. 3. The rest of the features are similar to those of the example shown in FIG. 8. Also in cases where the depicted in FIG. 9, a reactor 32f having a simple structure, it is possible to obtain a sufficient amount of methanol in the so-called "one-pass" reaction without using a circulation compressor 33.

FIG. 10 is a schematic diagram of another methanol synthesis plant 30 in the fertilizer plant 102 of FIG. 7. The methanol synthesis unit 30 illustrated in FIG. 10 includes neither compressor 31 nor circulation compressor 33 (see both in FIG. 2). Accordingly, as in the methanol synthesis unit 30 shown in FIG. 8 and 9, there is no partial recovery and return of the purge gas to the reactor 32b.

However, in the methanol synthesis plant shown in FIG. 10, the entire amount of purge gas from the upstream side separator 32d through heat exchanger 32e is supplied to a reactor 32f which is different from the above-described reactor 32b. The reactor 32f is, as described above, an adiabatic reactor, and the vessel 32f2 holds a methanol synthesis catalyst 32b1 of the same type as the catalyst located in the above-described reactor 32b.

In the reactor 32f, supplied with a purge gas from the upstream side separator 32d, methanol is formed from unreacted hydrogen and carbon dioxide. In addition, the reaction gas after the methanol formation reaction in the heat exchanger 32e gives off heat to the purge gas and is cooled by the heat exchanger 32g through which cooling water flows (not shown). When the reaction gas is cooled in a heat exchanger 32g, the methanol gas is converted to a liquid. Thus, liquid methanol is recovered from the bottom of the separator 32h located on the downstream side of the heat exchanger 32g. On the other hand, unreacted hydrogen or the like is recovered from the top of the separator 32h, and the outgoing hydrogen or the like is supplied to the reformer 1 or to a boiler not shown (or both) and used as a combustion fuel.

As indicated above, in the methanol synthesis unit 30 shown in FIG. 10, a reactor 32b is used, which performs cooling (air cooling or water cooling) during the methanol synthesis reaction, and a reactor 32f, which does not perform such cooling during the methanol synthesis reaction (that is, an adiabatic type of reaction is realized). This is done to accelerate the methanol synthesis reaction while cooling in the reactor 32b in the first stage, where the concentration of hydrogen and carbon dioxide in the supplied gas is high, and as a result, a large amount of methanol and heat is generated. On the other hand, in the second stage reactor 32f, where the concentration of hydrogen and carbon dioxide in the gas is reduced after passing through the first stage reactor 32b, the methanol synthesis rate is not so high (the reaction rate is low) and the amount of heat generated is not so high. Thus, the process can be realized only by an adiabatic reaction without cooling.

In addition, by using two kinds of reactors 32b and 32f, it is possible to induce a reaction of methanol synthesis with unreacted gas exiting the reactor 32b without using a circulation compressor 33 as shown in FIG. 2. Thereby, by eliminating the circulation compressor 33, an energy saving effect can be achieved.

FIG. 11 is a schematic diagram of another methanol synthesis plant 30 in the fertilizer plant 102 of FIG. 5. In the embodiment shown in FIG. 11 in the example instead of the reactor 32b shown in FIG. 10 upstream of the two reactors 32b, 32f, a reactor 32f (adiabatic reactor) similar to the reactor 32f described with reference to FIG. 3. Thus, in the example shown in FIG. 11, two identical reactors 32f are used. Otherwise, all its features are similar to those of the example shown in FIG. ten.

Also in cases where the two shown in FIG. 11 of the reactor 32f, each of which has a simple structure, it is possible to obtain a sufficient amount of methanol in the so-called "one-pass" reaction without using the circulation compressor 33. Thus, by eliminating the circulation compressor 33, it becomes possible to achieve the energy saving effect.

FIG. 12 is a system diagram of a fertilizer production plant 103 according to a fourth embodiment of the present invention. In the illustrated FIG. 12 to a fertilizer plant 103, similar to the above-described fertilizer plant 100 (see FIG. 1), the hydrogen recovered by the hydrogen recovery device 14 is returned to the upstream side of the compressor 11 through the hydrogen circulation system 72. However, unlike the aforementioned fertilizer plant 100, the methanol synthesis plant 30 is supplied with hydrogen not only through a branch from the hydrogen circulation system 72, but also through a hydrogen supply system 78 branching out from the position between the compressor 11 and the ammonia synthesis device 12. Thus, the methanol synthesis unit 30 produces methanol using at least a portion of the hydrogen contained in the ammonia synthesis feed gas that is compressed by the compressor 11.

As described above, by using a portion of the hydrogen contained in the feed gas compressed by the compressor 11, it is possible to supply the methanol synthesis unit 30 with high pressure hydrogen. As a result, there is no need to provide a compressor 31 (see FIG. 1) on the upstream side of the methanol synthesis unit 30 for compressing a feed gas containing hydrogen. At the same time, the concentration of hydrogen and the concentration of nitrogen in the feed gas intended for introduction into the ammonia synthesis device 12 are sufficiently high, while the concentrations of other components are relatively low. That is, when producing methanol using a gas having a relatively high hydrogen concentration and a relatively high nitrogen concentration with relatively low concentrations of other components, it is possible to increase the partial pressure of hydrogen and nitrogen and improve the yield of methanol.

FIG. 13 is a system diagram of a fertilizer production plant 104 according to a fifth embodiment of the present invention. In the illustrated FIG. 13 to a fertilizer plant 104, similar to the above-described fertilizer plant 100 (see FIG. 1), the hydrogen recovered by the hydrogen recovery device 14 is returned to the upstream side of the compressor 11 through the hydrogen circulation system 72. However, unlike the aforementioned fertilizer plant 100, the methanol synthesis plant 30 is supplied with hydrogen via a hydrogen supply system 79 branching from a position between the reformer 1 and the conversion reactor 2 in a manner independent of the hydrogen circulation system 72. Moreover, in addition to hydrogen, the hydrogen supply system 79 includes carbon monoxide, carbon dioxide and the like, produced by the reformer 1, compounds.

In addition, the methanol synthesis unit 30 is also supplied with carbon dioxide recovered by the above-described carbon dioxide recovery unit 3 and a compressed compressor 21. More specifically, a portion of the carbon dioxide compressed by the compressor 21 is connected to the hydrogen supply system 79 and supplied to the synthesis unit 30 methanol together with hydrogen, carbon monoxide and carbon dioxide produced by the reformer 1. Thus, the methanol synthesis unit 30 is configured to produce methanol using a portion of the hydrogen produced by the reformer 1 serving as a reformer, when This hydrogen is supplied upstream of the ammonia synthesis unit 10, the urea synthesis unit 20 and the methanol synthesis unit 30.

With a hydrogen supply system 79, branching from a position between the reformer 1 and the conversion reactor 2, it is possible to produce methanol using hydrogen and a carbon source gas (e.g. carbon dioxide) generated by the reformer 1. Thus, there is no need for a separate supply of the methanol synthesis plant 30 with a carbon source gas and it becomes possible to simplify the piping system.

FIG. 14 is a system diagram of a fertilizer production plant 105 according to a sixth embodiment of the present invention. In the plant 105 for the production of fertilizers, as well as in the installation 102 for the production of fertilizers, the production of methanol is carried out in the unit 30 for methanol synthesis using at least a portion of the hydrogen downstream of the unit 12 for ammonia synthesis.

In addition, in the plant 105 for the production of fertilizers, the plant 32 for the synthesis of methanol has a structure shown, for example, in FIG. 8-11. In addition, in the fertilizer plant 105, the off-gas from the separator 32d in the case of FIG. 8 and 9, or waste gas from separator 32d in the case of FIG. 10 and 11 is supplied to the hydrogen recovery apparatus 14 described with reference to FIG. 1, through the 75 release system. The off-gas from each of the separators 32d, 32h contains hydrogen. Thus, the hydrogen recovered by the hydrogen recovery unit 14 is returned to the upstream side of the methanization unit 4 through the hydrogen circulation system 77.

Accordingly, it is possible to use hydrogen in the exhaust gas. In addition, as described above, the circulating compressor 33 is no longer required and thus energy saving is possible. In addition, in addition to hydrogen, the hydrogen recovery device 14 is capable of recovering carbon monoxide and carbon dioxide. Thus, by returning to the upstream side of the methanizer 4, it is possible to convert carbon monoxide and carbon dioxide to methane.

List of reference positions.

1 Reformer;

2 Reactor of conversion;

3 Carbon dioxide extraction device;

4 Methanization device;

10 Ammonia synthesis unit;

11, 21, 31 Compressor;

12 Ammonia synthesis device;

13 Ammonia extraction device;

14 Hydrogen recovery device;

20 Urea synthesis unit;

21, 31 Compressor;

22 Urea synthesis device;

30 Methanol synthesis unit;

32 Methanol synthesis unit;

32b, 32f Reactor;

32d, 32h Separator;

32a, 32c, 32e, 32f, 32g Heat exchanger;

32b1 Methanol synthesis catalyst;

32f1, 32f2 Capacity;

33 Circulation compressor;

40 Formaldehyde synthesis unit;

41 Oxidizing reactor;

42 Absorber;

51 Mixer;

61 Granulating device;

71 Ammonia supply system;

72, 77 Hydrogen circulation system;

73, 74, 76, 78, 79 Hydrogen supply system;

75 Exhaust system;

100, 101, 102, 103, 104, 105 Plant for the production of fertilizers.

Claims (36)

1. A fertilizer plant for producing a fertilizer containing urea from a hydrocarbon source, wherein such a fertilizer plant comprises: a reformer for producing at least hydrogen and a carbon source gas by reforming the hydrocarbon source; an ammonia synthesis unit for producing ammonia using at least a nitrogen and hydrogen source gas produced by a reformer; a urea synthesis unit for producing urea using at least a carbon source gas obtained from a reformer and ammonia obtained from an ammonia synthesis unit; a methanol synthesis unit for producing methanol using at least hydrogen obtained by the reforming unit and a carbon source gas obtained by the reforming unit; a formaldehyde synthesis unit designed to produce formaldehyde by oxidizing methanol obtained by a methanol synthesis unit; an installation for obtaining a urea-formaldehyde composition, designed to produce a urea-formaldehyde composition using at least urea obtained using a urea synthesis unit and formaldehyde obtained using a formaldehyde synthesis unit; and a fertilizer production unit designed to produce fertilizers using at least urea obtained using a urea synthesis unit and a urea-formaldehyde composition obtained using a urea-formaldehyde composition unit. 2. Installation for the production of fertilizer according to claim 1, in which the methanol synthesis unit is configured to produce methanol using excess hydrogen from the ammonia synthesis unit. 3. Installation for the production of fertilizers according to claim 1 or 2, in which the methanol synthesis unit is configured to produce methanol using a carbon source gas produced by the reforming unit. 4. Installation for the production of fertilizers according to any one of paragraphs. 1-3, in which the ammonia synthesis unit includes an ammonia synthesis device for producing ammonia using at least a nitrogen and hydrogen source gas produced in the reformer and a hydrogen recovery device for recovering excess hydrogen from the ammonia synthesis device, moreover, the methanol synthesis unit is configured to produce methanol using hydrogen recovered using said hydrogen recovery device. 5. Installation for the production of fertilizers according to any one of paragraphs. 1-3, in which the ammonia synthesis unit includes an ammonia synthesis device for producing ammonia using at least a nitrogen and hydrogen source gas produced in the reformer and a hydrogen recovery device for recovering excess hydrogen from the ammonia synthesis device, moreover, the methanol synthesis unit is configured to produce methanol using hydrogen sampled between the ammonia synthesis unit and the hydrogen recovery unit. 6. Installation for the production of fertilizers according to any one of paragraphs. 1-3, wherein the ammonia synthesis unit includes an ammonia synthesis unit for producing ammonia using at least a nitrogen and hydrogen source gas produced by the reformer, and moreover, the methanol synthesis unit is configured to produce methanol using hydrogen from the side downstream of the ammonia synthesis unit. 7. Installation for the production of fertilizers according to any one of paragraphs. 1-6, in which the ammonia synthesis unit includes: an ammonia synthesis device for producing ammonia using at least a nitrogen and hydrogen source gas produced by a reformer; and a compressor designed to provide compression of a feed gas that contains hydrogen and a nitrogen source gas and is intended to be introduced into an ammonia synthesis device, moreover, the methanol synthesis unit is configured to produce methanol using hydrogen contained in the feed gas compressed by a compressor. 8. Installation for the production of fertilizers according to any one of paragraphs. 1-7, in which the methanol synthesis unit is configured to produce methanol using hydrogen obtained from the reforming unit, while said hydrogen is on the side upstream of the ammonia synthesis unit, urea synthesis unit and methanol synthesis unit. 9. A method for producing a urea-containing fertilizer from a hydrocarbon source, the method comprising: a reforming step for producing at least hydrogen and a carbon source gas by reforming the hydrocarbon source; an ammonia synthesis step for producing ammonia using at least a nitrogen and hydrogen source gas obtained in the reforming step; a urea synthesis step for producing urea using at least the carbon source gas obtained in the reforming step and ammonia obtained in the ammonia synthesis step; a methanol synthesis step for producing methanol using at least hydrogen obtained in the reforming step and a carbon source gas obtained in the reforming step; a formaldehyde synthesis stage for producing formaldehyde by oxidizing methanol obtained in the methanol synthesis stage; a step for producing a urea-formaldehyde composition for producing a urea-formaldehyde composition using at least the urea obtained in the urea synthesis step and formaldehyde obtained in the formaldehyde synthesis step; and a fertilizer production stage for producing a fertilizer using at least urea obtained at the stage of urea synthesis and a urea-formaldehyde composition obtained at the stage of obtaining a urea-formaldehyde composition.

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