JPH04154602A - Adiabatic reformer reactor - Google Patents

Abstract

PURPOSE:To facilitate the enlargement of a device for preparing hydrogen, methanol, etc., by dividing into the first reforming reactor and the second reforming reactor, disposing a floating style heat exchange device in the first reforming reactor and absorbing the thermal expansion of the first reforming reactor with a bellow. CONSTITUTION:A hydrocarbon and water as raw materials are fed into the reactor 3 of the first reforming reactor 1 from a passage 2 and brought into countercurrent contact with a high temperature second reformed gas fed from the outside of the reactor 3 to the first reforming reaction ion order to carryout the first reforming reaction by heat exchange. The first reformed gas discharged from the reactor 3 is collected in the lower floating section 5 and subsequently fed into the combustion chamber 9 of the second reforming reactor through a passage 7 from an outlet 6. A bellow 11 is disposed between a floating head 10 and an outlet nozzle 6 in order to avoid a thermal stress caused by difference of the thermal expansion of the reactor 3. The first reformed gas is mixed with an oxygen-containing gas fed from a passage 12 for the partial oxidation reaction and passed through a second reforming catalyst layer 13. The second reformed gas is fed into the shell side section of the first reforming reactor through a passage 14 from the bottom of the second reactor, subjected to a heat exchange and discharged from a passage 15 as a synthetic gas.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a device for producing reformed gas, which is used in a large-scale hydrogen production device, methanol production device, or ammonia production device.

(Prior Art) The development of large-scale equipment is required in order to use large quantities of hydrogen as future clean energy and methanol as a low-pollution, easy-to-transport, inexpensive fuel.

The biggest problem in the development of such large-scale hydrogen equipment and methanol production equipment is the increase in the size of the gas reformer that produces reformed gas from natural gas. Since the reaction tube is heated externally,
For example, in methanol production equipment, 1500 to 200
0T/D is the limit for large equipment.

Recently, a system that combines steam reforming and partial oxidation has been attracting attention as a gas reformer in large-scale equipment. This involves mixing natural gas and steam to perform a primary reforming reaction, then adding oxygen to perform partial oxidation and secondary reforming reactions, and using the resulting high-temperature gas as the heating source for the primary reforming reaction. It is something. As described in Japanese Patent Publication No. 50-20959, this method uses a single reactor and can obtain high-pressure reformed gas without supplying heat from other sources, making it easier to produce higher-pressure hydrogen. can be manufactured. Furthermore, when producing methanol or ammonia, the synthesis reaction can be carried out immediately without using a reformed gas compressor to increase the pressure. Furthermore, there is no need to use a reforming furnace that externally heats the reaction tube, and since the reforming reaction is carried out under high pressure, it is easy to increase the size of the apparatus.

Regarding the self-heat exchange type reactor (hereinafter referred to as an adiabatic reformer apparatus) that performs the -order qualitative reaction and the secondary reformer reaction in this way, JP-A-60-186401 and JP-A-1-2
Specific structures are shown in JP-A No. 61201, JP-A-2-18303, etc., and JP-A-2-3614 shows a methanol production process using an adiabatic reformer device.

(Problem to be solved by the invention) The old Japanese Patent Application Publication No. 1864/1986 has a heat exchange chamber for performing the primary reforming reaction in the upper part of the reactor, a secondary reforming catalyst layer in the middle part, and a combustion chamber in the lower part. The -order quality gas passes through the pipe in the center of the secondary reforming catalyst layer, enters the combustion chamber, mixes with the oxygen-containing gas supplied from the bottom of the reactor, undergoes partial oxidation, and then undergoes secondary reforming. The resulting high-temperature secondary reformed gas that comes into contact with the secondary reforming catalyst heats the reaction tube in the heat exchange chamber. This reactor has a structure that supports the weight of the secondary reforming catalyst layer with a refractory arch in the combustion chamber, but the temperature of the combustion chamber is 1.
Since the temperature exceeds 300℃, it is difficult to maintain consistency between the strength of the refractory material and the design of the arch structure; ■The gas flow in the secondary reforming catalyst layer is upward, so if the gas flow rate is increased, the catalyst There are issues such as concerns about the phenomenon of fluidization.

Further, in JP-A-1-261201, the reforming reaction tube is a double tube, and oxygen-containing gas is passed through the inner tube to perform partial oxidation and secondary reforming reaction in the lower part of the reaction tube. This reactor is difficult to employ in large-scale equipment because it is necessary to uniformly pass the reformed gas and oxygen-containing gas through a large number of reaction tubes.

Further, JP-A-2-18303 discloses a reactor in which a combustion chamber and a container for a secondary reforming catalyst layer are suspended below a group of primary reforming reaction tubes. In this reactor, the combustion chamber reaches a high temperature, so it needs to be lined with fire-resistant castable, and it is difficult to increase the size of the reactor because it is quite heavy.

JP-A-2-3614 discloses a flow in which the primary reforming reaction tube is a double tube, and the -order material gas passes through the inner tube and is introduced into the secondary reforming reactor. In this method, a primary reforming reactor and a secondary reforming reactor are provided separately, and the temperature introduced into the secondary reforming reactor is lowered by passing through the inner tube of the -second reforming reactor. Therefore, the amount of oxygen-containing gas used increases, and the temperature at the upper part of the primary reforming reaction tube increases, resulting in a decrease in the amount of heat recovery, which is a problem. Furthermore, since a tube sheet with double tubes is used and it is necessary to seal off the high temperature gas at that portion, the device becomes complicated and it is difficult to increase the size of the device.

(Means for Solving the Problems) As a result of intensive study of the adiabatic reformer equipment, which has the above-mentioned problems and is difficult to scale up, the inventor divided it into a secondary reforming reactor and a secondary reforming reactor. -We discovered that if a floating heat exchanger structure was used in the secondary reforming reactor and a bellows was used to absorb the thermal expansion of the primary reforming reaction tube, an excellent reactor that could be used in large-scale equipment could be obtained. This led to the invention.

That is, the present invention performs a primary reforming reaction using a mixed gas of hydrocarbons and steam, then adds an oxygen-containing gas to perform partial oxidation, and then performs a secondary reforming reaction, and the resulting high-temperature gas is subjected to the primary reforming reaction. In the reactor used as a heat source for Reactor designed to absorb thermal expansion (b) The secondary reforming reactor is a separate reactor with a combustion chamber in the upper part and an adiabatic catalyst layer in the lower part. - After the heat of the secondary reforming reaction is introduced from the top into a reaction tube filled with a reforming catalyst to perform a primary reforming reaction, it passes through a floating section and is led to a secondary reforming reactor, where it is introduced into a combustion chamber containing oxygen. Partial oxidation is performed by mixing with gas, and then a secondary reforming reaction is performed in the adiabatic catalyst layer, and the resulting high-temperature gas is heated countercurrently to the primary reformed gas from the lower part of the shell side of the primary reforming reactor. This is a heat insulating reformer device that is characterized by being able to be replaced.

In the apparatus of the present invention, there are cases where the outlet nozzle for the primary reformed gas of the primary reforming reactor is installed at the bottom, and cases where this nozzle is installed at the top of the primary reforming reactor using a central pipe. Next, each case will be explained using the drawings.

FIG. 1 is a drawing showing the structure of the adiabatic reformer apparatus of the present invention in which the outlet nozzle for the primary reformed gas of the primary reforming reactor is installed at the bottom. In the primary reforming reactor 1, raw material hydrocarbons and steam are introduced through a flow path 2 and enter a reaction tube 3. This reaction tube is filled with a reforming catalyst, and the gas inside the tube contacts the high temperature secondary reformed gas outside the tube in a countercurrent manner, thereby carrying out a primary reforming reaction of hydrocarbons. Note that this heat exchange chamber is preferably provided with a baffle 4 in order to increase its efficiency. The primary reformed gas leaving the reaction tube is collected in the lower floating part 5, reaches the outlet nozzle 6, and enters the combustion chamber 9 of the secondary reforming reactor 8 through the flow path 7. In order to avoid thermal stress caused by the difference in thermal expansion of the reaction tube, Hero-11 is installed between the floating head IO and the outlet nozzle.
It is sealed with a

In the combustion chamber, the gas is mixed with oxygen-containing gas introduced from the flow path 12, and a partial oxidation reaction is performed. Next, the partially oxidized gas passes through the secondary reforming catalyst layer 3 to undergo a secondary reforming reaction, and then passes through the flow path 14 from the bottom of the secondary reactor to the shell of the primary reforming reactor. The gas enters the lower part of the side, heats the inside of the reaction tube, and is discharged from the flow path 15 to become synthesis gas.

Note that the primary reforming reactor and the secondary reforming reactor are provided with a manway 16 for filling the catalyst and an inspection hole 17, so that catalyst replacement and reactor inspection can be easily performed.

FIG. 2 is a diagram of the reaction apparatus of the present invention in which a central tube is used in the primary reforming reactor and an outlet nozzle is installed in the upper part of the reactor. In this figure, gas from the floating section 5 passes through the central tube 18 to the outlet nozzle 6 at the top of the reactor. Further, a hero 20 is installed between the lower tube plate 19 and the tip of the central tube.

In Figures 1 and 2, a heat insulating material with a thickness of about 150 to 25001111 mm is installed on the inner surfaces of the primary reforming reactor and secondary reforming reactor, and on the inside of each manway and each gas nozzle. Further, the bellows is fixed by welding to the end plate and the outlet nozzle, or to the tube plate and the center tube.

In the above reactor, natural gas containing methane as a main component is usually used as the raw material hydrocarbon, but LPG, naphtha, etc. may also be used depending on the location conditions.

Also, in order to improve the raw material consumption rate, bar 7 gas from the synthesis system is mixed with hydrocarbons.

A nickel-based catalyst is usually used as a reforming catalyst, but the raw material hydrocarbon must be desulfurized in advance to avoid a decrease in the activity of the reforming catalyst. Steam is used so that the steam/carphone ratio of the hydrocarbon and steam mixture is usually 2.5 to 3.5, and is preheated to 400 to 600°C before being fed to the reactor.

The primary reforming reaction in the adiabatic reformer apparatus of the present invention is
Pressure 50-120 kg/cm2G, temperature 500-8
The reaction was carried out at 00°C, and the temperature was 700°C at the outlet of the reaction tube.
~800°C. In an adiabatic reformer, the pressure difference between the inside and outside of the reaction tube is small, so the reforming reaction pressure can be increased, and as mentioned above, high-pressure hydrogen can be obtained, and methanol and ammonia can be produced without using a reformed gas compressor. It can be used for synthetic reactions. Moreover, it is easy to increase the size.

The gas exiting the -order reaction tube is then mixed with oxygen-containing gas in a combustion chamber, where a partial oxidation reaction takes place. As the oxygen-containing gas, high-purity oxygen gas is usually used in the case of hydrogen production or methanol production, and air is used in the case of ammonia production. The amount of oxygen-containing gas used varies depending on the composition of the hydrocarbon feedstock, the supply temperature, etc., and is determined by the heat balance of the adiabatic reformer equipment.

If necessary, a portion of the raw material hydrocarbons may be introduced into the combustion chamber together with the oxygen-containing gas, or a portion of water vapor may be introduced into the combustion chamber to control the temperature of the combustion chamber. The -order gas and oxygen-containing gas can be mixed together or supplied separately using a double pipe or the like. Gas introduced into these combustion chambers 1: It is preferable to preheat the gas before supplying it as much as possible in view of the heat balance of the adiabatic reformer apparatus, and the gas is normally supplied at a temperature of 300 to 500°C.

The temperature of the combustion chamber varies depending on the supply temperature, the oxygen content, the supply amount, etc., but is usually 1300-1600°C. A secondary reforming catalyst is packed below this combustion chamber.
A secondary reforming reaction takes place. For the secondary reforming catalyst (= usually a nickel-based or platinum-based catalyst is used,
The reaction takes place at 'c.

(Effects of the Invention) The adiabatic reformer device of the present invention has two advantages: (1) By using a floaty two-flat structure, a C seal is not required in the primary reforming reactor, and the structure of the reactor is simple; (2) a bellows structure is used; By using it, it has the characteristics that thermal expansion of reaction tubes etc. can be easily absorbed, and conventional! It can be easily manufactured using exchanger technology, and it is also easy to increase its size.

This facilitates the enlargement of reformed gas generators in large-scale hydrogen production equipment, methanol equipment, etc., and has great industrial significance.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the structure of the adiabatic reformer device of the present invention in which the primary reformed gas outlet nozzle is installed at the bottom, and Fig. 2 is a diagram showing the structure in which the primary reformed gas outlet nozzle is installed at the bottom. . In FIG. 1 and FIG. 2, 1. primary reforming reactor, 3. primary reforming reaction tube, 5: floating section, 8. Secondary reforming reactor, 9: Combustion chamber lI: Bellow ■3: Shows the secondary reforming catalyst layer. Patent applicant Mitsubishi Gas Chemical Co., Ltd. Agent Patent attorney Sadafumi Kobori? Figure Figure

Claims (1)

[Claims] Performing a primary reforming reaction from a mixed gas of hydrocarbons and steam,
Next, in an adiabatic reformer device in which an oxygen-containing gas is added to perform partial oxidation and then a secondary reforming reaction, and the resulting high-temperature gas is used as a heating source for the primary reforming reaction, (a) the primary reforming reactor is A reactor in which a vertical floating heat exchanger is used, the heat transfer tube is a reaction tube filled with a reforming catalyst, and the thermal expansion of the reaction tube is absorbed by a bellows. (b) Secondary reforming reactor The reactor is a separate reactor with a combustion chamber in the upper part and an adiabatic catalyst layer in the lower part, and a mixed gas of raw material hydrocarbon and steam is introduced from the upper part of the primary reforming reactor into a reaction tube filled with a reforming catalyst. After performing the primary reforming reaction, it passes through a floating section and is guided to the secondary reforming reactor, where it is mixed with oxygen-containing gas in the combustion chamber to perform partial oxidation, and then secondary reforming occurs in the adiabatic catalyst layer. An adiabatic reformer device characterized by carrying out a reaction and exchanging heat of the obtained high-temperature gas with the primary reformed gas in a countercurrent flow from the lower part of the body side of the primary reforming reactor.