JPH03199103A - Reforming device for methanol - Google Patents

Abstract

PURPOSE:To facilitate operation and the maintenance and inspection of device and equipment at the time of reforming a methanol-water mixed vapor in the presence of a catalyst with a combustion gas by controlling and changing the distribution ratio of the raw gas liq. mixture. CONSTITUTION:The raw methanol-water liq. mixture separated into a passage 13 is introduced into a raw material evaporator 9 through a mixing header 10, heated by the low-temp. combustion gas after giving off its heat to a reforming tube bank, vaporized and sent to a raw gas header 4 through a raw gas header 11, and a part of the gas is introduced into a superheated gas from a raw material superheater 5 through a flow control valve B. The raw gas mixed by the raw gas header 4 is introduced into the raw gas superheater 5, heated by the high-temp. combustion gas and superheated. The superheated gas is adjusted to an optimum temp. for the reforming reaction and passed through a raw gaseous mixture inlet header 8 and a reforming tube to form a gaseous product.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an improvement in a methanol reforming reaction apparatus for producing a reformed gas containing hydrogen as a main component by a steam reforming reaction of methanol.

(Prior art) The method for producing reformed gas whose main component is hydrogen using methanol as a raw material is easy to transport and store the raw methanol, and the reforming reaction can be easily carried out at a relatively low temperature. As hydrogen gas of the desired quality can be produced extremely easily, it has come to be used not only in the chemical industry, but also in the electronics industry, food industry, and new industrial fields such as fuel cell power generation. It's here.

The mixed vapor of methanol and water undergoes a methanol decomposition reaction and a co-modification reaction by a catalyst in a reforming reactor, and becomes a reformed gas containing hydrogen as a main component.

CH30H+H20# CO2+3H214,8kca
The reforming (decomposition) reaction of l/mole methanol is an endothermic reaction, and the amount of heat required for the reforming reaction must be supplied by heating the reaction tube filled with the catalyst from the outside. Generally speaking, the supply of reaction heat, that is, the heating of the reaction tube, is
This is done by heat transfer oil flowing outside the catalyst tube. The heating method using heat transfer oil has a large overall heat transfer coefficient, allows for a compact reactor design, and is extremely easy to control the reaction temperature, so it has already been used as an industrial device. It has been put into practical use. However, in addition to the reactor/reactor, it requires incidental equipment such as a heat medium oil boiler and a heat medium circulation pump, and has the disadvantage that the reforming reaction apparatus is quite complicated and expensive.

If the combustion gas generator is integrated into the reforming reactor (tube) and designed to heat the catalyst tube directly with the combustion gas without using heat transfer oil, it will become a heat transfer oil boiler. Because it is an extremely simple reforming reaction device that does not require any incidental equipment such as 54-236
No. 83, JP-A-62-70202, JP-A-62-26
No. 0701, JP-A-63-138301, JP-A-63
-138306 etc.). However, when heating the catalyst tubes with combustion gas, the overall heat transfer coefficient is extremely small, less than 1/1O, compared to when heating oil is used. Is required. Increasing the temperature of combustion gas, which is a heating medium, requires a catalyst with better heat resistance. Proposals have already been made regarding heat-resistant catalysts containing noble metals such as platinum as an active ingredient, but these have drawbacks such as being extremely expensive and producing many side reaction products (CO gas).

On the other hand, copper-based catalysts, which have already been praised as methanonyl reforming catalysts, are highly active at low temperatures and produce few side reaction products.
It has a long catalyst life and is inexpensive, making it ideal as an industrial catalyst, but it has the characteristic of low heat resistance. As a countermeasure against this, for example, there is a method (Japanese Patent Publication No. 57-42678) of arranging reactors filled with catalysts with different heat resistance (300°C, 520°C) in series;
A method using low-temperature combustion gas (380°C) obtained by mixing a large amount of secondary air with high-temperature combustion gas as a heating medium (Japanese Unexamined Patent Publication No. 6
No. 0-246201> etc. have been proposed.

[Problem that the invention seeks to solve]

Method (2) above extends the catalyst life and improves operability, but the reformer is complicated because it requires two reactors, making it difficult to make it compact. Although it is expected that the followability will be considerably improved, since a large amount of secondary air is required, the required power will be large, and it is presumed that it will be extremely difficult to obtain inexpensive hydrogen gas.

In addition, from the viewpoint of pollution prevention and energy saving, kerosene and/or methanol are generally used as fuel for combustion gas generators, and hydrogen purifiers (PS) are used as fuel for combustion gas generators.
A) purge gas is used. However, in general,
Normally, at startup, purge gas is not available, so the composition of the combustion gas changes, and the heat transfer coefficient on the outside of the tube changes.

In addition, when the load fluctuates, the heat transfer coefficient inside and outside the tube changes, making it difficult to control the temperature distribution of the catalyst layer within the optimum operating temperature range of the reforming catalyst. It has a drawback in that it can only be used to its fullest potential.

[Means for solving problems]

The inventor conducted intensive studies on the structure and arrangement of the components of a methanol reformer that uses combustion gas as a heat medium, and the relationship between them and the overall heat transfer coefficient. Furthermore, the raw material evaporator and the reforming reactor are configured as a plurality of vertical tube groups, and the raw material evaporator (1), The raw material superheater, reforming reactor, and raw material evaporator (2) are installed, and the high temperature combustion gas is first used as a heat source for the raw material evaporator (1) and the raw material superheater, and then the temperature is lowered. Each device is arranged so that the medium-temperature combustion gas is used as a heat source for the reforming reactor, and finally, the low-temperature combustion gas whose temperature has further decreased is used as a heat source for the raw material evaporator (2), and further, temperature of the catalyst layer of the reforming reactor,
In other words, the reaction temperature can be adjusted very easily and precisely by changing the distribution and supply ratio of the raw methanol-water mixture to the raw material evaporator (1) and the raw material evaporator (2). It has been found that the temperature distribution of the layer can be controlled within a predetermined temperature range. Based on this knowledge, the present inventor conducted intensive improvement research and completed the present invention.

Hereinafter, the present invention will be explained in more detail based on a basic configuration diagram. 1 and 2 are basic configuration diagrams of a methanol reforming reactor according to the present invention, and are specific examples of preferred embodiments.

The raw material methanol-water mixture supplied from the raw material storage tank (not shown in FIG. 1) through the metering pump (not shown in FIG. 1) and the flow path 12 is transferred to the flow path 13 and
It is branched and divided into a flow path 14. The raw material methanol-water mixture branched and divided into the flow path 14 passes through the flow rate control valve A1 and the mixed liquid header (1) 3 to the raw material evaporator (1) 2.
The raw material gas is heated by high-temperature combustion gas to evaporate and vaporize, and then is guided to the raw material mixed gas inlet header 8 via the raw material gas header (1) 4 and the raw material gas superheater 5. On the other hand, the raw material methanol-water mixture branched and divided into the flow path 13 passes through the mixed liquid header (2) 10 to the raw material evaporator (2) 9
It is heated by the low-temperature combustion gas that has finished supplying heat to the reforming reaction tube group, evaporates and vaporizes, and is led to the raw material gas header (1) 4 via the raw material gas header (2) 11. At the same time, a part of it is introduced into the superheated gas from the raw material superheater 5 via the flow rate control valve B.

The raw material gases mixed in the raw material gas header (1) 4 are guided to the raw material superheater 5 and heated by high-temperature combustion gas to become superheated gas. The superheated gas is regulated and controlled to the optimum temperature range for the reforming reaction, either by merging and mixing with the raw material gas from flow control valve B, or without merging or mixing, and then passing through the raw material mixed gas inlet header 8. The gas is introduced into the reforming reaction tube 6, undergoes a reforming reaction, and becomes a reaction product gas.

The reaction product gas generated by the reforming reaction is taken out as a reaction product gas through the reaction gas outlet header 7 and the flow path 18, and sent to the next step for purification, or used as it is as appropriate.

As already described, the high-temperature combustion gas generated in the combustion gas generator 1 is first evaporated and vaporized in the raw material evaporator (1>2) and then passed through the raw material superheater 5.
The raw material gas is superheated to become medium-temperature combustion gas and guided to the reforming reaction tube group 6. The medium-temperature combustion gas heats the reforming reaction tube group to provide reaction heat and becomes low-temperature combustion gas.

The low-temperature combustion gas passes through the flow path 15 to the raw material evaporator (2) 9
The remaining heat is given as the latent heat of vaporization of the raw material methanol-water mixture, and then discharged into the atmosphere through the flow path 16.

When carrying out the present invention, as illustrated in FIGS. 1 and 2, a raw material evaporator (1), a raw material superheater, and
In the reforming reaction tube, a raw material evaporator (1) and a raw material superheater are arranged inside the same concentric cylindrical container, and a reforming reaction tube is arranged outside of the same. A partition wall 17 is provided between the reaction tube and the reforming reaction tube to prevent direct contact of high-temperature combustion gas to the reforming reaction tube. It is preferable to provide a clear temperature gradient. Further, the raw material evaporator (2) may be installed in the same cylindrical container as the reforming reaction tube, etc., but it is easier and simpler to manufacture it if it is installed in a separate cylindrical container.

When carrying out the present invention, the combustion gas generator 1 is generally placed in the upper part of a concentric cylindrical container from the viewpoint of ease of maintenance, as illustrated in FIG. Therefore,
Normally, the flow direction of combustion gas is that it first flows through the inner cylinder from the bottom to the top, gives heat to the raw material evaporator (1) and the raw material superheater to reach a medium temperature, and then flows through the reforming reaction tube group from the top. Although it is designed to flow downward, it is not necessarily limited thereto, and if desired, the combustion gas generation device may be placed at the bottom to reverse the flow direction of the combustion gases. In addition, the flow direction of the combustion gas and the reaction gas in the reforming reaction tube group is generally preferably parallel flow from the viewpoint of the reforming reaction rate, that is, the heat absorption rate, but countercurrent flow may be preferable depending on the heat resistance performance of the catalyst. may be used, and is optional.

The raw material evaporator (1) and the reforming reaction tube are located at predetermined positions on the concentric circumference within the concentric cylindrical container, and the raw material superheater is located at the upper part of the raw material evaporator (1) of the combustion gas generator. It is preferable to arrange the raw material evaporator (2) in a spiral shape in the surrounding combustion gas flow path.In addition, it is easier to manufacture the raw material evaporator (2) and install it in a cylindrical container separate from the reforming reaction tube. It is preferable.

Hereinafter, a preferred embodiment of the present invention will be described in which the reforming reaction apparatus shown in FIG. 1 is used. In addition,
The examples illustrated below are merely for concretely explaining the effects of the present invention, and are not intended to limit the technical scope of the present invention.

Example 1 The present invention will be explained in more detail with reference to an example carried out using the reformer shown in FIG. 1. In the following examples, alumina sol was added to a coprecipitate prepared by a coprecipitation method using copper nitrate and zinc nitrate as raw materials, and the mixture was calcined.
φX3. Copper-zinc-aluminum catalyst formed into a cylindrical shape of Qmm [catalyst composition atomic ratio Cu:2n:A1=1. o
o:o, 75:0.25, JP-A-59-189937
No. 21 of Example 1] was filled into each reforming reaction tube (48 tubes) with a nominal diameter of 81 1/4 inches and a length of 2.4 m.
An activated methanol reforming catalyst was used, which was activated by reducing the catalyst with hydrogen gas according to a conventional method.

Example 1 is a case in which only kerosene is used as the fuel for the combustion gas generating device 1, and assumes that the device is cold-started. First, after replacing the inside of the device with hydrogen gas,
The combustion gas generator 1 was ignited according to a conventional method. After about 30 minutes after the apparatus was gradually warmed up, the temperature of the reforming catalyst layer reached 230 to 250°C, and the temperature of the reformed gas outlet header 8 reached 250°C.

Here, the fuel flow rate is set to 0.9 kg/h, the raw material methanol-water mixture supply pump (omitted in Fig. 1) is started, and the raw material methanol-water mixture (mixture molar ratio CI1) is started. .OH:H20=1.0:1.5) is divided into flow path 13 and flow path 14 via a preheater (omitted in Figure 1, preheating temperature 100°C) and flow path 12. The flow path 13 passes through the mixed liquid header (2) 10 to the raw material evaporator (2) 9, and the flow path 14, the flow rate control valve A1, and the mixed liquid header (1) 3 to the raw material evaporator (1).
2 (flow rate: IO 30 kg/h), the reforming reaction was started.

Next, while maintaining the gas pressure (reforming reaction pressure) in the reforming reaction system at IQ ata according to a conventional method, the fuel flow rate and the flow rate of the raw material methanol-water mixture are gradually increased to reduce the raw material methanol-water mixture. The flow rate was set at 23.6 kg/h. During this time, the temperature distribution of the catalyst layer is controlled so that the tube wall temperature of the reforming reaction tube does not exceed 360°C, and the temperature of the raw methanol-water mixed gas in the mixed gas header 8 becomes 230°C. The flow control valve A1, the flow control valve B1, and the fuel flow rate were adjusted and controlled so that the width of the flow rate was the minimum value.

In this way, approximately 55 minutes after starting the supply of the raw material methanol-water mixture, the operating condition of the apparatus reached a steady state, and 41 Nm3/h of reformed gas was produced.

Subsequently, the reforming reaction experiment was continued for 36 hours while maintaining a steady state, and the results (average values) shown in Tables 1 and 2 were obtained. Raw material evaporator (1) in this experiment, and
The evaporation rate (average value) of the raw material evaporator (2) is 12:
1, and the methanol conversion rate (average value) was 99%. The fuel consumption (average value) is 1.9 kg/h, and the temperature distribution of the reforming reactor catalyst layer is 2 in the length direction of the catalyst layer.
The temperature range was 30 to 259°C, and the fluctuation range was substantially constant at 10 to 20°C. The heat loss from the cylindrical wall of the reforming reactor was 670 kcal/h.

Table 2 Reformed gas composition (mole fraction) Example 2 Example 2 is a case in which purge gas from a hydrogen gas purification device (pressure swing adsorption purification method) and kerosene are used together as the fuel for the combustion gas generator 1. , assuming normal steady operation of the device.

In Example 1, the purge gas from the hydrogen gas purification device and kerosene were used together instead of only kerosene as the fuel for the combustion gas generator 1, and the raw material methanol-water mixture flow rate was 59.
．． The continuous reforming reaction was continued for 72 hours in the same manner as in Example 1 except that the rate was changed to 1010 kg/h.
0 N/h of the reformed gas and the results (average values) shown in Tables 3 and 4 were obtained. The raw material evaporator (1
), and the evaporation rate (average value) of the raw material evaporator (2)
is 4.3:1, and the methanol conversion rate (average value) is 9.
It was 8%. In addition, the fuel consumption (average value) is 34 Nm3/h of purge gas and 1.3 kg/h of kerosene, and the temperature distribution of the reforming reactor catalyst layer is 2 in the length direction of the catalyst layer.
The temperature range was 30-266°C, and the variation range was substantially constant at 10-20°C.

Note that the heat loss from the cylindrical wall surface of the reforming reactor was 1.680 kcal/h at the fire source.

Table 4 Reformed Gas Composition (Mole Fraction) Comparative Example 1 In Example 2, the shutoff valve C of the flow path 13 was closed to prevent the vaporization and evaporation of the raw material methanol-water mixture from the raw material evaporator (1
)2 except that the reforming reaction was carried out in the same manner as in Example 2. As a result, the combustion gas temperature in the reforming reaction tube 6 population decreased to 680°C, and the methanol conversion rate (average value ) was an extremely low value of 81.2%.

〔effect〕

According to the present invention, the reforming reaction temperature is controlled by changing the distribution and supply ratio of the methanol-water mixture, which is the raw material, to the raw material evaporator (1) and the raw material evaporator (2). As a result, the structure of the reforming reactor is extremely simple, and as a result, it is easy to operate and
This is an on-site hydrogen gas generator that allows for easy maintenance, inspection, and maintenance of equipment and equipment.

[Brief explanation of drawings]

1 and 2 show an embodiment of the methanol reforming reactor according to the present invention, FIG. 1 is a sectional view of the methanol reforming reactor, and FIG. 2 is a-a in FIG. 1. FIG. 1: Combustion gas generator, 2: Raw material evaporator (1), 3: Mixed liquid header (1) 4: Raw material gas header (1), 5: Raw material gas superheater, 6: Reforming reaction tube, 7: Reaction Gas outlet header 8: Raw material gas population header 9: Raw material evaporator (2), mixed liquid header (2), raw material gas header (2), bulkhead, flow control valve, flow control valve shutoff valve

Claims (1)

[Claims] In a methanol reforming reactor that reacts a mixed vapor of methanol and water with combustion gas in the presence of a catalyst, a raw material evaporator (1), a raw material superheater, a reforming reactor, and a raw material are arranged in the flow direction of the combustion gas. The reforming reaction temperature is controlled by sequentially arranging the evaporators (2) and controlling and changing the distribution and supply ratio of the raw material methanol-water mixture to the raw material evaporator (1) and the raw material evaporator (2). A methanol reforming reaction device characterized by: