JPS61227902A - Reforming apparatus - Google Patents

Abstract

PURPOSE:To save energy consumption of a reforming process by heat exchanging previously gaseous mixture of feed gas and steam introduced into a reforming pipe with combustion waste gas at high temp. used for heating in the reforming reaction, heat-exchanging further with reformed gas discharged from the reforming pipe. CONSTITUTION:Plural numbers of reforming pipe 9 closed at one end and provided with reforming catalyst bed in the inside and having annular section are provided to the inside of a reforming vessel 1. Combustion gas is burnt with combustion air in a burner 4, generated hot combustion waste gas is let flow down between the plural reforming pipes 9 and discharged through a heat exchanger 24. At the same time, gaseous mixture of the feed gas and steam is introduced through a conducting pipe 13 into the heat exchanger 24 to exchange the heat with the hot combustion waste gas. The gas is further introduced into a heat exchanger 25 to exchange the heat with the reformed gas discharged from the reforming pipe 9. The gas is then introduced into the reforming pipe 9 to exchange the heat with the hot combustion waste gas. The gas is reformed by the heating and obtd. reformed gas is discharged to the outside through the heat exchanger 25.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a hydrocarbon system that is introduced into a reforming tube using reformed gas and combustion exhaust gas flowing out from the reforming tube in a reformer container. The present invention relates to a reformer device that can efficiently promote a reforming reaction by increasing the concentration of a mixed gas of raw material gas and water vapor to an appropriate temperature using a heat exchanger.

[Technical Background of the Invention] In recent years, there has been a lot of expectation and interest in research into the development and practical application of fuel cells. Fuel cells oxidize the chemical energy contained in fuel through an electrochemical process, resulting in the generation of oxidation reactions. It is a device that converts the emitted energy directly into electrical energy.

A power generation plant using this fuel cell has a thermal efficiency of 40 to 50% in power generation even on a relatively small scale, and is expected to far exceed new thermal power generation. Furthermore, emissions of sulfur oxides and nitrogen oxides, which are factors that have become a major social problem in recent years, are extremely low. Furthermore, since the power generator does not include a combustion cycle, it can be expected to have high energy conversion efficiency in principle, such as not requiring a large amount of cooling water and low vibration noise, as well as reducing environmental problems such as noise and exhaust gas. Furthermore, it has features such as good responsiveness to load fluctuations. In a power generation plant using such a fuel cell, hydrogen gas obtained by mixing water vapor with hydrocarbon-based raw material gas such as natural gas and heating it in a reformer is mixed with hydrogen gas from other systems. In many cases, air from a turbo compressor is supplied to a fuel cell for an oxidation reaction to generate electricity.

Figure 3 is a system diagram showing an example of a reformer installed in this type of fuel cell power generation plant, and Figure 4 is a longitudinal cross-sectional view of an example of the configuration of the reformer main body in Figure 3. thing, 5th
The figure shows a plan view taken along the line I-IF in FIG. 4.・In the figure, inside the reformer container 1, fuel from a conduit 2 connected to a fuel tank (not shown) and air from a conduit 3 connected to an air supply machine (not shown) are respectively introduced and mixed, and the main fuel is combusted. A burner 4 is provided, and an auxiliary burner 7 is provided, into which fuel is introduced through a conduit 5 and air is introduced through a conduit 6, respectively, and which has an electric ignition device at its tip for igniting the main burner 4. There is. The high-temperature combustion exhaust gas from the main burner 4 flows through the heating chamber 8, passes through the outer peripheral space of the reforming tube 9 having an annular cross section, passes through the conduit 10 holding the ceramic spheres 11 in the lower layer, and is roughly The reforming organ I is connected to the reforming organ I through the exhaust gas pipe 12 communicating with this.
11, and is led to a turbo compressor (not shown) to contribute to operation. On the other hand, a mixed gas of a hydrocarbon-based raw material gas such as natural gas and water vapor is introduced from a conduit 13 to a reformer in a reforming tube 9 .

It passes through a conduit that holds a soot layer (hereinafter simply referred to as a soot layer) 14. During this passage, a reforming reaction takes place due to heating and catalytic action, and the gas is reformed into hydrogen-rich gas. This reformed gas is guided to the outside of the reforming organ 11 via a conduit 15 in the reforming tube 9 and further via a conduit 16 communicating with this, and is reduced in concentration by a heat exchanger 21 and is thereby reformed. The gas is supplied to a fuel cell (not shown) through a high-temperature shift converter 23 that converts carbon monoxide contained in the gas into carbon dioxide, and a low-temperature shift converter (not shown), thereby contributing to power generation.

[Problems with background technology]

By the way, as this type of device, for example, Japanese Patent Laid-Open No. 53-79
In the above-mentioned reformer as disclosed in Japanese Patent No. 767, the temperature of the mixed gas of raw material gas and steam on the reformer tube 9 intake side needs to be controlled to 427° C. or higher and 510° C. or lower. The reason is that when the temperature falls below 427°C, polypropylene is deposited on the catalyst layer 14, deteriorating the performance of the catalyst.
Furthermore, when the temperature exceeds 510°C, the mixed gas decomposes and generates carbon, which enters the structure of the catalyst layer 14, destroys the catalyst, and pulverizes it, increasing the differential pressure inside the reforming tube 9. be. In fact, as the mixed gas of raw material gas and steam introduced from the lower part of the reforming tube 9 in the reformer container 1 rises through the catalyst layer 14 in the reforming tube 9,
The temperature rises to 760°C or above, causing a reaction to reform into hydrogen gas, and the seed burner 4 in the reformer vessel 1 is used to raise the temperature at the top of the reforming tube 9 to a maximum of 982°C. The tube 9 is heated and controlled. The hydrogen-rich gas thus reformed flows down through the conduit 15 on the inside of the reforming tube 9 and reaches the catalyst II! 14, and the temperature at the exit side of the reforming tube 9 is controlled at approximately 593°C.

The gas reacted and reformed in the reforming tube 9 contains -carbon oxide CO, which is harmful to the battery body, so in order to convert this into harmful carbon dioxide CO2, the temperature of the reformed gas is set at approximately The temperature is lowered from 593°C to a range of 387°C or more and 421°C or less using the cooling gas in the conduit 22 in the heat exchanger 21,
Carbon monoxide C is introduced into the high-temperature shift converter 23 and subjected to a catalytic reaction.
Converts O to carbon dioxide CO2. The basic reforming reaction equation for fuel and steam mixed gas is shown below.

Reaction inside the reforming tube CH4+2H2+heat → CO+H2
0+3H2 Reaction in high-temperature shift converter CO+820 → Heat+CO2+82 From the above explanation, in order to reform the mixed gas of raw material gas and steam into hydrogen-rich gas using the catalyst 1l 114 filled in the reforming tube 9, reforming is necessary. It can be seen that heating must be carried out efficiently so that the mixed gas of raw material gas and steam reaches an appropriate temperature in the range of 427 DEG C. to 510 DEG C. at the inlet of the tube 9. and the temperature of the gas reformed in the reforming tube 9 is about 5
The appropriate temperature for putting 93°C into the high-temperature transformer 23 is 387°C to 42°C.
It can be seen that the temperature must be lowered to within 1°C.

However, in conventional reformers, the temperature of the mixed gas of natural gas and steam is raised from about 200°C to the appropriate temperature range of 427°C to 510°C for introducing it into the reforming tube 9 using the heat exchanger 19. and the heat loss of giving a large amount of thermal energy to the
There was a drawback that temperature control was difficult because the temperature difference in the heat exchanger 19 was large.

and heat loss that releases a large amount of thermal energy to lower the temperature of the gas discharged from the reforming tube 9 from about 593°C to the appropriate temperature range of 387°C to 421°C for introducing it into the high-temperature shift converter 23 through the heat exchanger 21. However, there is a problem in that temperature control is difficult due to the large temperature difference during heat exchange.

[Purpose of the Invention] The present invention was made to solve the above-mentioned problems, and its purpose is to efficiently carry out the reforming reaction and save energy, and to An object of the present invention is to provide a reformer device that can easily control the temperature of a mixed gas of raw material gas and water vapor to an appropriate temperature and can save energy.

[Summary of the Invention] To achieve the above object, the present invention provides heat exchange between a mixed gas of raw material gas and steam introduced into the reforming tube and high temperature combustion exhaust gas after passing outside the reforming tube. a first heat exchanger that performs heat exchange, and a second heat exchanger that performs heat exchange between the mixed gas of raw material gas and steam heat exchanged by the first heat exchanger and the reformed gas discharged from the reforming tube. A first feature is that a heat exchanger is provided inside each of the reformer vessels, and in addition, a first heat exchanger is provided to directly guide the reformed gas discharged from the reformer tubes to the outside of the reformer vessel. and a second bypass pipe that guides the reformed gas from the reforming tube after passing through the second heat exchanger to the outside of the reformer container, and the reformed gas is introduced into the reforming tube. a temperature detector that detects the temperature of a mixed gas of raw material gas and water vapor;
A first control valve provided in the first bypass pipe to adjust the flow rate of reformed gas in the pipe; and a second control valve provided in the second bypass pipe to adjust the flow rate of reformed gas in the pipe. and a controller that compares the detected concentration from the concentration detector and a prescribed mixed gas concentration, and controls the opening degrees of the first control valve and the second control valve, respectively, according to the comparison result. The second feature is that it comprises the following.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be specifically described with reference to the drawings. Fig. 1 shows a system diagram of a reformer device according to the present invention, Fig. 2 shows a configuration example of the reformer device in a vertical sectional view, and Figs. Components that are the same as those of the conventional type shown in FIGS.

1 and 2, a main burner 4 is provided at the top of the reformer vessel 1, and its combustion port is connected to the reformer fs.
It is installed as shown in the inside part of 1. Further, an auxiliary burner 7 having an electric ignition device in its combustion nozzle is arranged to be able to ignite the main burner 4. Roughly speaking, below the main burner 4, a plurality of reforming pipes 9 each having an annular cross section are arranged in a uniform arrangement. The high-temperature combustion exhaust gas combusted in the main burner 4 flows down the intervals between the plurality of reforming tubes 9 while heating the reforming tubes 9, and the lower outer circumference of the reforming tubes 9 is filled with ceramic balls 11. It passes through conduit 10 and communicates therewith via a heat exchanger 24 which communicates therewith. The exhaust gas is discharged from the reformer container 1 through a conduit 12, contributing to the operation of a turbo compressor (not shown) that utilizes heat from the exhaust gas, and releasing the exhaust gas. On the other hand, a mixed gas of hydrocarbon-based raw material gas and steam is introduced from the conduit 13, and in the heat exchanger 24, heat is exchanged with the high temperature combustion exhaust gas combusted in the main burner 4 to increase the temperature of the mixed gas,
This heated mixed gas is introduced into a heat exchanger 25 disposed in the heat exchanger 24, and is introduced into the reforming tube 9 through this.

Then, this introduced mixed gas passes through the catalyst layer 14 filled inside the reforming tube 9, enters the conduit 15 inside the top of the reforming tube 9, and a part of it passes through the conduit 26 communicating with this. The hydrogen-rich reformed gas is guided out of the reformer vessel 1 from the conduit 16 through the heat exchanger 25. in this case,
An automatic control valve 27 is provided on the guide 1!16. The remaining part'' is directly led out of the reformer container 1 from one end of the conduit 26. In this case, an automatic control valve 28 is provided in the conduit 26, and the automatic control valve 27 is connected downstream of the automatic control valve 27. A bypass pipe 29 is provided which communicates with the conduit 16.Then, the heat exchanger 121 and the high temperature transformer 23 are passed through the conduit 16.
The fuel is supplied as fuel to the fuel cell via a low-temperature transformer (not shown).

In addition, the automatic control valves 27 and 28 are connected to a temperature detector 30 for a mixed gas of raw material gas and steam at a conduit portion introduced into the reforming pipe 9.
Accordingly, proportional control is performed in conjunction with the automatic controller 31. That is, by comparing the detected temperature from the temperature detector 30 and the specified mixed gas concentration (427 to 510°C),
As a result of the comparison, when the detected temperature is lower than the specified mixed gas temperature, the control valve 28 is controlled in the closing direction and the control valve 27 is controlled in the open direction, and conversely, when the detected temperature is higher than the specified mixed gas temperature, the control valve 28 is controlled in the open direction. The valve 27 is controlled in the closing direction, and the control valve 28 is controlled in the opening direction.

In the reformer device configured as described above, a mixed gas of raw material gas and steam is introduced through the conduit 13 into a heat exchanger 1124 provided in the reformer B1. On the other hand, the combustion gas is combusted by the main burner 4, and the high m combustion exhaust gas is reformed! 9 flows down while being heated, enters the heat exchanger 24 through the conduit 10, and exchanges heat with the above-mentioned mixed gas. Further, the mixed gas heated in the heat exchanger 24 is introduced into the communicating heat exchanger 25, and on the other hand, it is reformed! The high-temperature exhaust gas reformed in the heat exchanger 25 is introduced into the heat exchanger 25, where it exchanges heat with the mixed gas to efficiently raise the temperature to an appropriate temperature necessary for reforming because the heating temperature difference is appropriate. It becomes possible.

Furthermore, what about the mixed gas of raw material gas and steam introduced into the reforming tube 9? The temperature is detected by a temperature detector 30, and when the concentration is higher than the appropriate temperature, the automatic control valve 28 increases its opening degree under the control of an automatic controller 31 linked to the temperature detector 30, and controls inversely proportional to the temperature. As a result, the opening degree of the automatic control valve 27 becomes smaller.

Through this control, the amount of reformed gas from the reforming tube 9 is reduced to the heat exchanger 2.
5, the heating energy for the mixed gas is reduced and the temperature rise is reduced. Further, when the temperature detected by the temperature detector 30 is lower than the appropriate temperature, the opening degree of the automatic control valve 28 is similarly reduced, and the opening degree of the automatic control valve 27 is increased by controlling inversely proportional to it.
Through this control, the temperature of the mixed gas increases in the heat exchanger 25.

With the above control, the mixed gas of raw material gas and steam entering the reforming tube 9 can be efficiently maintained at an appropriate temperature necessary for reforming.

On the other hand, the gas reformed by the reforming pipe 9 is transferred to the heat exchanger 25.
Since the heat exchanger 21 is installed before introducing the high temperature transformer 23,
It becomes possible to reduce the energy of the cooling gas 22 in order to lower the temperature to an appropriate temperature to be introduced into the high-temperature shift converter 23.

As described above, according to the reformer device of this configuration, the 2 m heat exchangers 24 and 25 provided in the reformer container 1 provide
Since the temperature of the mixed gas of hydrocarbon-based raw material gas and steam introduced into the reforming tube 9 can be adjusted to the appropriate temperature required for reforming, the reforming reaction to produce a hydrogen-rich gas can be carried out extremely efficiently. At the same time, it is possible to save energy.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be similarly implemented in the following manner.

(a) In the above embodiment, the heat exchangers 24 and 25 may be arranged on the outer periphery of the reformer container 1.

(b) In the above embodiment, a partition plate is provided at the lower part of the reforming tube 9, and the heat exchangers 24 and 25 are placed in separate containers.
It may be possible to make it removable.

[Effects of the Invention] As explained above, according to the present invention, heat exchange is performed between the mixed gas of raw material gas and steam introduced into the reforming tube and the high-temperature combustion exhaust gas after passing through the reforming tube. A first heat exchanger, and a second heat exchanger for exchanging heat between the mixed gas of raw material gas and steam heat exchanged by the first heat exchanger and the reformed gas discharged from the reforming tube. a first bypass pipe for directly guiding the reformed gas discharged from the reforming pipe to the outside of the reformer container; 2
A second bypass pipe is provided to guide the reformed gas from the reforming pipe after passing through the heat exchanger to the outside of the reformer container, and the mixed gas of raw material gas and steam introduced into the reforming pipe is a temperature detector for detecting temperature; a first control valve provided in the first bypass pipe to adjust the amount of reformed gas in the pipe; and a first control valve provided in the second bypass pipe to adjust the amount of reformed gas in the pipe. * A second control valve that adjusts Since the structure is equipped with a controller that controls the opening degree of each tube, the reforming reaction can be carried out efficiently and energy can be saved. It is possible to provide an extremely reliable reformer device that can easily control the mixed gas temperature to an appropriate temperature and save energy.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an embodiment of the reformer device of the present invention;
Fig. 2 is a longitudinal sectional view showing the reformer device, Fig. 3 is a system diagram showing the conventional reformer device, Fig. 4 is a longitudinal sectional view showing the conventional reformer main body, and Fig. 5 is a longitudinal sectional view showing the conventional reformer device. FIG. 4 is a plan view taken along the line I-1 in FIG. 4; DESCRIPTION OF SYMBOLS 1... Reformer container, 4... Main burner, 7... Auxiliary burner, 9... Reforming tube, 11... Ceramic bulb, 14... Catalyst layer, 21... Heat exchanger, 23...
High temperature transformer, 24 and 25...Heat exchanger, 27 and 28...
... Automatic control valve, 30 ... Temperature detector, 31 ... Automatic controller. Applicant's agent Patent attorney Takehiko Suzue'In1 Figure 2 Condolence 3 Figure 14 Figure

Claims (2)

[Claims] (1) A plurality of reforming tubes each having an annular cross-section, one end of which is sealed and a reforming catalyst layer provided inside, are arranged inside the reformer container, and combustion gas and combustion air are supplied to the burner. The high-temperature combustion exhaust gas obtained by combustion is caused to flow from one end of the reforming tube through the outside to the outside from the other end, and a mixed gas of raw material gas and water vapor is allowed to flow in from the other end of the reforming tube. In a reformer configured to be reformed into reformed gas through a reforming catalyst bed and further flowed out from one end through an inner pipe and the other end, a mixed gas of raw material gas and water vapor introduced into the reforming pipe. and a first heat exchanger that exchanges heat with the high-temperature combustion exhaust gas that has passed through the outside of the reforming tube, and a mixed gas of the raw material gas and water vapor heat-exchanged by the first heat exchanger, and the A reformer device characterized in that a second heat exchanger for exchanging heat with the reformed gas discharged from the reformer tube is provided inside or outside the reformer container, respectively. (2) A plurality of reforming tubes each having an annular cross-section, one end of which is sealed and a reforming catalyst layer provided inside, are arranged inside the reformer container, and combustion gas and combustion air are supplied to the burner. The high-temperature combustion exhaust gas obtained by combustion is caused to flow from one end of the reforming tube through the outside to the outside from the other end, and a mixed gas of raw material gas and water vapor is allowed to flow in from the other end of the reforming tube. In a reformer configured to be reformed into reformed gas through a reforming catalyst bed and further flowed out from one end through an inner pipe and the other end, a mixed gas of raw material gas and water vapor introduced into the reforming pipe. and a first heat exchanger that exchanges heat with the high-temperature combustion exhaust gas that has passed through the outside of the reforming tube, and a mixed gas of the raw material gas and water vapor heat-exchanged by the first heat exchanger, and the A second heat exchanger that exchanges heat with the reformed gas discharged from the reforming tube is provided inside or outside the reformer container, and a second heat exchanger that exchanges heat with the reformed gas discharged from the reforming tube is provided. a first bypass pipe that leads to the outside of the reformer container, and a second bypass pipe that leads the reformed gas from the reformer pipe after passing through the second heat exchanger to the outside of the reformer container, respectively. A temperature detector configured to detect the temperature of a mixed gas of raw material gas and water vapor introduced into the reforming pipe, and a first bypass pipe provided in the first bypass pipe to adjust the reformed gas flow rate in the pipe. comparing the temperature detected by the temperature sensor and a specified mixed gas temperature with a second control valve provided in the second bypass pipe and regulating the flow rate of the reformed gas in the pipe; A reformer apparatus comprising: a controller that controls the opening degrees of the first control valve and the second control valve, respectively, according to the comparison result.