JP4999364B2 - Methanol production equipment - Google Patents

Description

  The present invention relates to an apparatus for producing methanol that uses natural gas hydrate.

  In recent years, research on gas hydrates produced by bringing a raw material gas such as natural gas into contact with water has been underway. Hydrates are clathrate hydrates in which molecules (guests) of source gas are taken in clusters (cage structures) formed by water molecules. For example, natural gas hydrate is a structure in which natural gas composed mainly of methane, ethane, and propane is incorporated as a guest into a cluster composed of water molecules. Such a gas hydrate can be configured as various gas hydrates by replacing the raw material gas in addition to the natural gas hydrate. For example, if carbon dioxide is used as the source gas, carbon dioxide hydrate can be generated.

  Natural gas hydrate is a technique originally developed for the convenience of storage and transportation, as described in Patent Document 1, for example. For example, in the case of natural gas, it is currently common to store and transport in the form of liquefied natural gas (LNG). However, methane, which is the main component of liquefied natural gas, requires cryogenic conditions such as −162 ° C. for liquefaction, and maintenance of such cryogenic conditions is required for storage and transportation. For this reason, the production and maintenance of liquefied natural gas are costly.

  On the other hand, natural gas hydrate contains about 170 times the gas in an environment of −20 ° C. under atmospheric pressure, and exhibits a large self-preserving effect in an environment of about −20 ° C. For this reason, it has an advantage that handling in storage and transportation is relatively easy.

JP 2003-073679 A JP 2001-039911 A

  As described above, natural gas hydrate is a technology originally developed for convenience of storage and transportation. For this reason, the natural expectation for natural gas hydrate is a self-preserving effect in an environment of about −20 ° C. under atmospheric pressure. In other words, for storage and transportation, value is required for performance that is difficult to disassemble.

  On the other hand, natural gas hydrate decomposes into natural gas and water relatively quickly when placed in a room temperature environment. Such a phenomenon can be said to be avoided as much as possible if the natural expectation of natural gas hydrate is the convenience of storage and transportation. On the other hand, the inventors of this application rather focused on the phenomenon of decomposition of such natural gas hydrate, and proceeded earnestly research on its use. As a result, a methanol production apparatus was invented.

  Methanol is generally produced through a synthesis gas generation step, a synthesis step, and a distillation step (see paragraphs 0002 to 0004 of Patent Document 2). Among these processes, since it is necessary to apply a high pressure to the synthesis gas produced in the synthesis gas production process in the synthesis process, considerable scale equipment such as a compressor is required. As a result of paying attention to the phenomenon of decomposition of natural gas hydrate, the inventor of the present invention has come to invent a methanol production apparatus capable of producing methanol without requiring a considerable scale facility such as a compressor. It was.

The methanol production apparatus of the present invention has a storage unit capable of storing a natural gas hydrate, and includes a first discharge unit that discharges the natural gas generated by decomposing the natural gas hydrate in the storage unit to the outside. A natural gas supplied to the cracking apparatus and the first discharge unit through the first discharge unit is reacted with water vapor to generate synthesis gas, and the generated synthesis gas is discharged to the outside. A reformer having a second discharge unit and a synthesis gas that is communicated with the second discharge unit and supplied through the second discharge unit are reacted on a methanol synthesis catalyst to produce liquid crude methanol. A reaction apparatus having a third discharge unit for generating and discharging the generated crude methanol to the outside, and interposed between the reforming apparatus and the reaction apparatus, from the reforming apparatus to the reaction apparatus Cool the supplied synthesis gas Comprising a retirement unit, and the high-pressure space leading to the reactor through said reformer from the cracking unit by the synthesis gas derived from the natural gas natural gas and the natural gas hydrate is generated is decomposed To maintain the pressure required to produce crude methanol in the reactor.

  According to the present invention, methanol can be produced without requiring a considerable scale facility such as a compressor.

  An embodiment of the present invention will be described with reference to the drawings.

  The methanol production apparatus 101 includes a decomposition apparatus 201, a reforming furnace 211 as a reforming apparatus, a reaction furnace 221 as a reaction apparatus, a syngas cooler 231 as a cooling apparatus, and a purification tower 241 as a purification apparatus. Such a methanol production apparatus 101 produces methanol by utilizing the phenomenon of decomposition of the natural gas hydrate 301 of the natural gas hydrate 301 in the decomposition apparatus 201 with water.

  The decomposition apparatus 201 will be described. The decomposition apparatus 201 has a storage unit 202 that can store a natural gas hydrate 301, and discharges water and natural gas generated by the decomposition of the natural gas hydrate 301 in the storage unit 202 to the outside. It has the 1st discharge part 203 for natural gas, and the 4th discharge part 204 for water. The inside of the decomposition apparatus 201 is divided into two vertically by a porous holding table 205. The holding table 205 has a structure capable of holding the natural gas hydrate 301. Therefore, the space above the holding table 205 constitutes the storage unit 202 that can store the natural gas hydrate 301, and the space below the holding table 205 is generated by the decomposition of the natural gas hydrate 301. The water storage part 206 which stores water is comprised. The first discharge unit 203 communicates with the reforming furnace 211 through the first passage 207, and the fourth discharge unit 204 communicates with the synthesis gas cooler 231 and the purification tower 241 through the fourth passage 208. Yes. In FIG. 1, a fourth passage 208 communicating with the synthesis gas cooler 231 is represented by reference numeral 208a, and a fourth passage 208 communicating with the purification tower 241 is represented by reference numeral 208b. The fourth passage 208a and the fourth passage 208b are partially shared.

  The natural gas hydrate 301 is stored, for example, in an NGH tank 302 at −20 ° C., and is transferred from the NGH tank 302 to the storage unit 202 of the decomposition apparatus 201 as necessary.

  The reforming furnace 211 receives supply of natural gas from the cracking apparatus 201 via the first passage 207. The internal space of the decomposition apparatus 201 is at a high pressure due to the decomposition of the natural gas hydrate 301. Thus, the supply of natural gas to the reforming furnace 211 is performed while maintaining such a high pressure without using a special supply device. The reforming furnace 211 reacts the supplied natural gas with water vapor to generate a synthesis gas mainly composed of hydrogen, carbon monoxide and carbon dioxide. In order to cause such a reaction, the reforming furnace 211 includes a nickel-based catalyst (not shown). In the reforming furnace 211, natural gas and water vapor are reacted at a temperature of 800 to 1000 ° C. as an example under a nickel catalyst. As a result, synthesis gas mainly containing hydrogen, carbon monoxide, and carbon dioxide is generated. In addition, the temperature condition range at the time of producing | generating synthesis gas is not limited to the said range.

  The reforming furnace 211 has a second discharge unit 212 that discharges the generated synthesis gas to the outside. The second discharge unit 212 communicates with the reaction furnace 221 through the second passage 213.

  The reaction furnace 221 receives supply of synthesis gas from the reforming furnace 211 via the second passage 213. At this time, since the synthesis gas derived from natural gas is in a high pressure state even inside the reaction furnace 221, such a high pressure is also used for supplying the synthesis gas to the reaction furnace 221, and a special supply device is provided. It is carried out while maintaining a high pressure. The reaction furnace 221 reacts the supplied synthesis gas with methanol to produce liquid crude methanol. In order to cause such a reaction, the reaction furnace 221 includes a methanol synthesis catalyst (not shown) that is a copper-based catalyst. In addition, as the methanol synthesis catalyst, a zinc-based catalyst, a chromium-based catalyst, or the like may be used. In the reactor 221, the synthesis gas is reacted under the conditions of a pressure of 50 to 200 kg / cm 2 G and a temperature of 200 to 300 ° C. as an example under a methanol synthesis catalyst. Thereby, liquid crude methanol containing water and organic impurities is generated. Note that the pressure and temperature condition ranges for producing liquid crude methanol are not limited to the above ranges. However, as described above, the pressure for producing the liquid crude methanol is the pressure derived from the natural gas hydrate 301 decomposed by the decomposition apparatus 201. For this reason, when generating a high pressure state in the reactor 221, a special equivalent scale facility such as a compressor is not required.

  The reaction furnace 221 has a third discharge part 222 for discharging the generated liquid crude methanol to the outside. The third discharge unit 222 communicates with the purification tower 241 through the third passage 223.

  The syngas cooler 231 is disposed in a second passage 213 that allows the reforming furnace 211 and the reaction furnace 221 to communicate with each other. The syngas cooler 231 plays two roles. One is the role of cooling the synthesis gas flowing through the second passage 213 by bringing the water discharged from the fourth discharge section 204 into contact with the second passage 213 that is a passage of the synthesis gas. The other is the role of generating water vapor as the synthesis gas is cooled and supplying the generated water vapor to the reforming furnace 211 to be used as water vapor to react with natural gas. In order to be able to fulfill these two roles, the synthesis gas cooler 231 includes a space (not shown) that hermetically covers the second passage 213 that is a passage for the synthesis gas. The four passages 208a are in communication with each other, and the space portion and the reforming furnace 211 are in communication with each other through a steam passage 232. As an example, the temperature of the synthesis gas flowing through the second passage 213 is cooled to 200 to 300 ° C. by passing through the synthesis gas cooler 231.

  The purification tower 241 distills the liquid crude methanol supplied via the third passage 223 using the difference in boiling points of the components contained in the crude methanol, and discharges it as high-purity methanol. As an example, the purification column 241 includes a first distillation column (not shown) and a rectification column (not shown). First, in the first distillation column, from the crude methanol, a dissolved gas, a low boiling component, and the low boiling component. The mixed gas containing methanol accompanying the gas is separated, and this mixed gas is discharged from the top of the first distillation column. And a residual component is introduce | transduced into a rectification tower, In this rectification tower, a residual component is isolate | separated into refined methanol, a high boiling point component, and water.

  As described above, one fourth passage 208 b that guides water discharged from the fourth discharge unit 204 of the decomposition apparatus 201 communicates with the purification tower 241. The water supplied to the purification tower 241 via the fourth passage 208b is cold water, and serves to cool methanol that has become a gas during distillation in the purification tower 241. The purification tower 241 recirculates the supplied water used for cooling to the space part of the synthesis gas cooler 231 through the water passage 242. In the synthesis gas cooler 231, the water supplied from the purification tower 241 becomes steam and is supplied to the reforming furnace 211 through the steam passage 232. The steam supplied in this way is used as steam to react with natural gas in the reforming furnace 211.

  In such a configuration, in the decomposition apparatus 201, the natural gas hydrate 301 stored in the storage unit 202 is decomposed into natural gas and water as the temperature rises. At this time, since the storage unit 202 of the decomposition apparatus 201 has a high pressure, the natural gas and water generated by the decomposition are discharged to the outside. As a result, the natural gas is supplied from the first discharge unit 203 to the reforming furnace 211 via the first passage 207. Water is supplied from the fourth discharge unit 204 to the synthesis gas cooler 231 through the fourth passage 208a, and is supplied to the purification tower 241 through the fourth passage 208b.

  Since the natural gas supplied to the reforming furnace 211 is maintained in a high pressure state, it is supplied as a synthesis gas to the reaction furnace 221 through the second passage 213, and passes through the third passage 223 from the reaction furnace 221. Then, it is supplied to the purification tower 241 as crude methanol. For this reason, the synthesis gas derived from the natural gas hydrate 301 flowing through the second passage 213 has a high temperature. Therefore, the water derived from the natural gas hydrate 301 supplied through the fourth passage 208a and the fourth passage 208b are supplied to the synthesis gas cooler 231 disposed in the second passage 213. The water derived from the natural gas hydrate 301 supplied to the purification tower 241 through the water passage 242 after being supplied to the purification tower 241 through the water passage 242 becomes water vapor by contacting the second passage 213. . The steam generated in this manner is supplied to the reforming furnace 211 via the steam passage 232 and used as steam to react with the natural gas supplied via the first passage 207. As a result, in the reforming furnace 211, natural gas and water vapor react at a temperature of, for example, 800 to 1000 ° C. under a nickel-based catalyst to generate synthesis gas.

The synthesis gas generated in the reforming furnace 211 is supplied to the reaction furnace 221 through the second passage 213. In the reactor 221, the supplied synthesis gas undergoes a methanol reaction with a methanol synthesis catalyst, and liquid crude methanol is generated. At this time, the reactor 221 must be maintained at a high pressure in order to produce crude methanol. The methanol production apparatus 101 uses the pressure derived from the natural gas hydrate 301 decomposed by the decomposition apparatus 201 as the pressure required to produce crude methanol. For this reason, according to the methanol production apparatus 101, when generating a high pressure state in the reaction furnace 221, there is no need to rely on a special equivalent scale facility such as a compressor.

  Crude methanol produced in the reaction furnace 221 is distilled in a purification tower 241. Thereby, methanol with high purity can be obtained.

It is a schematic diagram of the methanol manufacturing apparatus which shows one Embodiment of this invention.

Explanation of symbols

201 Decomposing device 202 Storage unit 203 First discharging unit 204 Fourth discharging unit 211 Reforming furnace (reforming device)
212 Second discharge portion 213 Second passage (syngas passage)
221 reactor (reactor)
222 3rd discharge part 231 Syngas cooler (cooling device)
241 Purification tower (refining equipment)
301 Natural gas hydrate

Claims (5)

A decomposition device having a storage unit capable of storing natural gas hydrate, and having a first discharge unit for discharging natural gas generated by decomposition of natural gas hydrate in the storage unit to the outside;
A second exhaust unit that communicates with the first exhaust unit, reacts the natural gas supplied through the first exhaust unit with water vapor to generate synthesis gas, and exhausts the generated synthesis gas to the outside A reformer having
The synthesis gas supplied to the second discharge unit through the second discharge unit is reacted on the methanol synthesis catalyst to generate liquid crude methanol, and the generated crude methanol is discharged to the outside. A reactor having a third outlet;
A cooling device that is provided between the reformer and the reactor and cools the synthesis gas supplied from the reformer to the reactor;
Equipped with a,
The space from the cracker to the reactor through the reformer is maintained at a high pressure by the natural gas produced by the decomposition of the natural gas hydrate and the synthetic gas derived from the natural gas, thereby the reaction. The pressure required to produce crude methanol in the device was obtained,
Methanol production equipment.   The methanol production apparatus according to claim 1, further comprising a refining device that communicates with the third discharge unit and distills the crude methanol supplied through the third discharge unit. The decomposition apparatus includes a fourth discharge unit that discharges water generated by decomposition of natural gas hydrate in the storage unit to the outside.
The cooling device is configured to bring water discharged from the fourth discharge section into contact with a synthesis gas passage to cool the synthesis gas and generate water vapor, and supply the generated water vapor to the reformer. Use as water vapor to react with natural gas,
The methanol production apparatus according to claim 1 or 2. The decomposition apparatus includes a fourth discharge unit that discharges water generated by decomposition of natural gas hydrate in the storage unit to the outside.
The purification device uses water discharged from the fourth discharge part as cooling water.
The methanol production apparatus according to claim 2. The decomposition apparatus includes a fourth discharge unit that discharges water generated by decomposition of natural gas hydrate in the storage unit to the outside.
The cooling device is configured to bring water discharged from the fourth discharge section into contact with a synthesis gas passage to cool the synthesis gas and generate water vapor, and supply the generated water vapor to the reformer. Use as water vapor to react with natural gas,
The purifier uses the water discharged from the fourth discharge part as cooling water, supplies the water after being used as cooling water to the cooling apparatus, and uses it as water to contact the passage of the synthesis gas.
The methanol production apparatus according to claim 2.

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