JPS60210503A - Reforming apparatus - Google Patents

Abstract

PURPOSE:To obtain a reformed gas with high efficiency by measuring the temp. of each reformer tube to control the amt. of combustion gas, and measuring the pressure of each reformer tube to regulate the amt. of reformed gas. CONSTITUTION:Combustion gas and air are supplied from each combustion gas line 22 and combustion air line 23 into a combustion chamber 3, and burned to heat each reformer tube 6. The tube temp. of each reformer tube 6 is measured by a temp. measuring element 15, and the mean temp. is determined. The opening degree of each combustion gas regulating valve 24 is respectively controlled to nullify the deviation between the measured temp. and the mean temp. The opening degree of a gas supply regulating valve 31 of a common line 32 is also controlled. Meanwhile, the pressure of each reformed gas line 26 is measured with a pressure measuring element 29, and the measured pressure difference and the allowable pressure difference are respectively compared to respectively regulate the opening degree of each reformed gas regulating valve 28 provided to the reformed gas line 26. The damage of the reformer tube 6 due to heat is prevented in this way, and the reforming efficiency at each reformer tube 6 is increased.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention is an improvement of a heated gas reformer in which reformed gas passes through a plurality of reforming tubes, and heating gas flows outside the tubes to heat them simultaneously. It is related to.

[Technical background of the invention]

The configuration of this type of gas reformer that is commonly used will be explained using the cross-sectional view shown in FIG. In the figure, a reformer 1 sends combustion gas and combustion air to a burner 2, combusts it in a combustion chamber 3, and directs the heated fluid generated by this combustion through a heating channel to an exhaust gas outlet 5. Discharge outside. This combustion heat heats a plurality of reforming tubes 6 having an annular cross section provided inside the reforming device 1.

Inside the reforming tube 6, a reformed gas flow path is provided completely separated from the combustion gas heating flow path 4. The reformed gas flowing in from the lower part of the reformed gas flows inside the catalyst layer 8 provided on the inner wall of the reforming tube 6 and supported by the lower perforated plate, rises, and reverses direction at the upper end. The reformed gas changes direction, flows through a return path 10 formed between the catalyst layer 8 and the center plug 9, and flows out from the reformed gas outlet 11.

During this time, reformed gas such as methane and water vapor is reformed into hydrogen and carbon dioxide gas.

In some cases, only one reforming pipe 6 is provided inside the reformer 1, but in general, a plurality of reforming pipes 6 are provided inside the reformer #i1 as shown in FIG.

[Problems with background technology]

By the way, in the above-mentioned reformer, when a plurality of reformer tubes 6 are provided in one reformer 1, there is a problem that the tube wall temperature of the reformer tubes 6 becomes non-uniform. This point will be described below using FIG. 2. FIG. 2 shows a cross-sectional tank bottom of the upper part of the reformer 6. In the figure, the reforming tube 6 is made by welding an end plate 12 and a weld line 13.

Since the upper portion of the reforming tube 6 near the combustion chamber 3 reaches a high temperature as already described in FIG. 1, a cap 14 made of a heat insulating material is placed over the end plate 12. Also,
Since defects are likely to occur in the weld line 13, a temperature measuring element 15 is provided at this portion to measure the temperature. The reformed gas rises in the catalyst JQ8, passes through the upper end 16 of the catalyst, reverses itself above the perforated plate 17, and descends through the return path 10 formed in the plug guide 19 to flow out. Note that 20 indicates a catalyst layer inner tube.

Now, as a result of actually manufacturing a single reformer with a plurality of reforming tubes 6, and conducting an experiment by installing a temperature measuring element 15 on the wall of each reforming tube 6, we found that It has become clear that the tube wall temperature is not uniform for each tube 6 and that a large temperature difference occurs. In other words, the operating temperature of the reforming tube 6 does not reach the failure life of the reforming tube 6, and the influence is large;
The 0°C increase in temperature will shorten the annual lifespan of SilO by about 3 years. Therefore, if there is non-uniformity in temperature among the reforming tubes 6, looking at the highest temperature among the non-uniform temperatures,
The reformer must be operated while adjusting the amount of combustion gas supplied to the burner 2 so that this maximum temperature becomes the limit temperature. However, in this case, the reforming efficiency deteriorates in the reforming tube 6 having the lowest temperature.

As mentioned above, the conventional reformer has the following problems.

If the tube wall temperature is uneven, the life of the high-temperature reforming tube 6 will be short, and the low-temperature reforming tube 6 will have poor reforming efficiency of the reformed gas, for example, converting methane and steam into hydrogen and carbonic acid. When reforming into gas, the amount of residual methane increases as the width of temperature non-uniformity increases. In other words, if operation is performed with the average tube wall temperature of a plurality of reforming tubes 6 adjusted to the limit temperature, the high temperature reforming tubes 6 will have a short lifespan and will not break quickly. Reforming tubes with low temperatures have poor reforming efficiency, and the more there are reforming tubes 6 with low temperatures, or the lower their temperatures are compared to the average temperature, the greater the amount of methane that is not reformed.
The overall reforming efficiency of the reformer will decrease.

[Purpose of the invention]

The present invention was made in order to solve the above-mentioned problems, and its purpose is to uniformize the tube wall temperature of each reforming tube in a structure with a plurality of reforming tubes, thereby increasing the lifespan. Another object of the present invention is to provide a reforming device that can carry out reforming with high efficiency.

[Summary of the invention]

In order to achieve the above object, the present invention includes a plurality of reforming tubes each having an annular cross section, one end of which is sealed, and a reforming catalyst layer is provided between an inner pipe line and an outer pipe line. The combustion gas and the heated fluid obtained by burning the combustion gas in the combustion chamber are discharged from one end of the reforming tube through the outside thereof to the outside from the other end, and the reformed gas is discharged from the other end of the reforming tube to the outside. In a reformer configured to allow inflow from one end through the reforming catalyst layer and outflow from the other end through the inner pipe from one end, the combustion chamber is provided independently for each reforming tube. a plurality of combustion gas control valves each provided on a plurality of combustion gas lines that allow the combustion gas to flow into each of the combustion chambers separately; and a plurality of combustion gas control valves that individually flow the reformed gas into each of the reforming pipes. Measure the reformed gas control valves installed on each of the reformed gas lines, the combustion gas supply control valve installed on the common line of each of the combustion gas lines, and the wall temperature of each of the reforming tubes. a pressure measuring element that measures the pressure difference between the inlet and outlet of the reformed gas of each of the reforming tubes;
The average temperature measured by each of the temperature measuring elements is compared with a predetermined limit temperature, and the combustion gas supply amount is adjusted to be zero based on the comparison result. a first valve controller for controlling the opening degree of the valve; and a second valve controller for separately comparing the average temperature with the temperature measured by each of the temperature measuring elements, and adjusting the inflow amount of the combustion gas based on the comparison result. 3. Comparing the measured pressure difference and the allowable pressure difference separately, and controlling the opening degree of the corresponding reformed gas control valve individually in order to adjust the inflow amount of the reformed gas based on the comparison result. and a pipe wall temperature control circuit comprising a valve controller.

[Embodiments of the invention]

First, in the present invention, the reason why the tube wall temperature of the reforming tube becomes uneven is that
One possible cause is that the combustion heating fluid becomes non-uniform around the reforming tube, but another reason is that the reformed gas flowing inside the reforming tube undergoes an endothermic reaction, resulting in an uneven flow of this gas. Uniformity is also considered as one of the factors, and we are particularly trying to deal with the latter cause.

An embodiment of the present invention shown in the drawings will be described below.

FIG. 3 is a cross-sectional view showing an example of the general configuration of the reformer according to the present invention, and the same parts as in FIGS. Now, I will only discuss the different parts. In this example, the number of 60 reforming tubes is three.

In Fig. 3, a heating burner 2 is provided for each of the three reforming tubes 6, and a heating burner 2 is provided for each of the three reforming tubes 6. A sleeve pipe 21 is disposed over the 2 parts of the burner. Also, in the figure,
Reference numeral 22 indicates three combustion gas lines for separately supplying combustion gas to each burner 2, 23 indicates a combustion air line for supplying combustion air to each burner 2, and 24 indicates each combustion gas line 22. Combustion gas control valves 25 are provided on the combustion air line 23, respectively. On the other hand, reference numeral 26 denotes three reformed gas pipes installed to separately supply the reformed gas flowing from the reformed gas lower into the reforming pipe 6 and into the reforming pipe lower chamber 27. The line 28 is a reformed gas control valve provided on each reformed gas line 26, 29 is provided corresponding to each reforming pipe 6, and the reformed gas pressure at the inlet and outlet of the pipe is With the pressure difference measuring element that measures the difference, the measured pressure difference is P□ #P! It is output as #Pl. Reference numeral 15 denotes a temperature measuring element which is provided on the upper end wall of each of the reforming tubes 6 and measures the temperature of the tube wall, and the measured temperatures are T1, T, respectively.

This is output as T3. Furthermore, 30 is a reformed gas discharge control valve provided at the reformed gas outlet section 11;
31 is a combustion gas supply amount control valve provided on the common line 32 of each combustion gas line 22; It is automatically adjusted accordingly.

FIG. 4 is a block diagram showing an example of a tube wall temperature control circuit applied to the present invention. In the figure, 33 indicates the temperature Te measured by each temperature measuring element 15. #'l"2t
An average temperature calculator 34 calculates the average temperature TA of T8, and 34 is the above-mentioned limit temperature Ts of the reforming tube, and the average temperature calculator 33
A first valve controller that receives as input the average temperature TA from
A valve opening control signal is given to the combustion gas supply amount regulating valve 31 in order to adjust the supply amount of the combustion gas so that the deviation between each temperature T8 and TA becomes zero. Also, 35
is a second valve controller provided corresponding to each of the reforming pipes 6, which controls the average temperature TA from the average temperature calculator 33 and the temperatures T1, T, measured by the temperature measuring elements 15, respectively.
.

T3 is individually compared, and a valve opening control signal is given to each corresponding combustion gas control valve 24 in order to adjust the inflow amount of the combustion gas so that the deviation becomes zero.

Furthermore, 36 is a third valve controller provided corresponding to each of the reforming pipes 6, which measures the allowable pressure difference Ps between the inlet and outlet of the reformed gas in the reforming pipe, and the pressure measuring elements of each of the above-mentioned pressure measuring elements. Compare the measured pressure differences P1, P, , P, respectively according to No. 29,
In order to adjust the inflow amount of the reformed gas so that this deviation becomes zero, a valve opening control signal is given to the corresponding reformed gas control valve 28, respectively.

Next, the operation of the reformer having such a configuration will be explained.

In the figure, the common line 32 and each combustion gas line 22
By sending the combustion gas and combustion air to the respective burners 2 of each reforming pipe 6 through the combustion air line 23, the combustion gas and combustion air are combusted in each combustion chamber 3 as described above. The heated fluid passes through the heating flow path 4 and is discharged to the outside through the exhaust gas outlet 5. On the other hand, the reformed gas flowing from the reformed gas population 2 flows into the lower chamber 27 of each reforming tube 6 through the reformed gas line 26 provided separately, and flows into the catalyst layer 8 of each reforming tube 6. The reformed gas flows through the interior of the reformed gas and rises, changes direction in the opposite direction at the upper end, flows through the return path 10 formed between the catalyst layer 8 and the centanolag 9, and flows out from the reformed gas outlet 11. During this time, reformed gas such as methane and steam is reformed into hydrogen and carbon dioxide in each reforming tube 6.

On the other hand, since the reforming reaction is an endothermic reaction as described above, heat is generated in each reforming tube 6 due to the reaction, and the temperature of the wall of the reforming tube 6 increases.

Then, the tube wall temperature Tl#TfilT3 of each reforming tube 6
is measured by the temperature measuring element 15 provided in each. Still, in the average temperature calculator 33, each of these measured temperatures KTz + T! The average temperature TA of t T* is determined. Next, the second valve control unit 35 compares each of the measured temperatures T14*rT3 with the average temperature TA, and determines whether the deviations between the respective temperatures T and TA, T, TAtT, and TA are zero. By individually controlling the valve opening degree of each combustion gas regulating valve 24 provided in each combustion gas line 22, the amount of combustion gas flowing into the reforming pipe 6 is adjusted so that The tube wall temperature of each reforming tube 6 is maintained at an average temperature TA.

Furthermore, in the first valve controller 34, each of the reforming pipes 6
The average temperature TA of 1 is compared with a preset limit temperature T8, and the combustion gas supply amount regulating valve 31 provided in the common combustion gas line 32 is adjusted so that the deviation between each temperature T8 and TA becomes zero. By controlling the valve opening of the reforming pipe 6,
The amount of combustion gas supplied to the reforming tubes 6 is adjusted to maintain the tube wall temperature of each reforming tube 6 at the limit temperature Ts. Further, in the third valve controller 36, each of the above-mentioned measured pressure differences PH#P2
* PB is compared with each of the above allowable pressure differences P8, and each pressure difference P□ and PB, P, and P8. By individually controlling the valve opening degree of each reformed gas control valve 28 provided in each reformed gas line 26, the reforming pipe 6 The inflow amount of the reformed gas into the reforming tubes 6 is adjusted so that the pressure difference between the inlet and the outlet of the reformed gas in each reforming tube 6 is an allowable pressure difference P.

is maintained.

Now, in the above, if the inflow of the reformed gas and combustion gas into each reforming tube 6 is uniform, gas reforming will be carried out by the above-mentioned reforming reaction without any problem. However, as the reforming reaction progresses, if the catalyst particles contained in the catalyst layer 8 in a particular reforming tube 6 are crushed or cracked due to sudden thermal changes caused by the reaction, the reforming The internal pressure loss of the catalyst layer 8 in the quality tube 6 changes, making it difficult for the reformed gas to flow into the tube, reducing the pressure at the tube inlet of the reformed gas and reducing its inflow amount. As a result, since the reforming tube 6 is cooled by the reformed gas inside, the wall temperature of the reforming tube 6 increases due to the decrease in the amount of reformed gas accompanying this pressure drop. Then, as the operating time of the apparatus passes, a difference in tube wall temperature appears between the reforming tube 6 and other reforming tubes 6 due to a decrease in the pressure of the reformed gas. In this case, as described above, in this reformer, the average temperature TA of each reformer tube 6 and its own tube wall temperature are compared, and the allowable pressure difference Ps between the inlet and outlet of the reformed gas and the own measurement Since the pressure difference is compared and the inflow amount of combustion gas and reformed gas into the tubes is adjusted separately based on this deviation, the tube wall temperature of each reforming tube 6 and the inlet of reformed gas are adjusted. The pressure difference between the outlet and the outlet will always be kept uniform. Furthermore, the average temperature TA of each of these reforming tubes 6 is the limit temperature T8 as described above.
Since the supply amount of combustion gas is adjusted based on this deviation, the tube wall temperature of each reforming tube 6, the reforming temperature, and the pressure difference between the inlet and outlet of the reformed gas are always kept constant. The limit temperature T8 and the allowable pressure difference P8 are maintained respectively.

Therefore, by using the reformer with this configuration, each reforming pipe 6
Since it is possible to always keep the tube wall temperature and the pressure difference between the inlet and outlet of the reformed gas uniform and within the limit temperature Ts and allowable pressure difference Psa, it is possible to
This makes it possible to improve the reforming efficiency of the entire apparatus by improving the reforming efficiency of the gas in each reforming tube 6 while preventing damage caused by heat. In addition, in this reformer, the reformed percentage
Since two sleeve tubes are provided concentrically with N 6 and have the same radial width in any direction from the reforming tube wall, the temperature difference in the circumferential direction of each reforming tube 60 is reduced and the above effects are further enhanced. can be encouraged.

In addition, in the above embodiment, the case of 6 or 3 reforming tubes was described, but
The present invention is similarly applicable to the case where there are two or more than four wires.

〔Effect of the invention〕

As explained above, according to the present invention, even in a configuration in which a plurality of reforming tubes are provided, the tube wall temperature of each reforming tube is made uniform, and reforming can be carried out with high efficiency while extending the service life. It is possible to provide a highly reliable reforming device that can perform the following steps.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the configuration of a conventional reforming device, FIG. 2 is a cross-sectional view showing the implantation of the upper end of the reforming tube in FIG. 1, and FIG. 3 is a cross-sectional view showing an embodiment of the present invention. The sectional view and FIG. 4 are block diagrams showing an example of a tube wall temperature control circuit applied to the present invention. 1... Reformer, 2... Burner, 3... Combustion device,
4... Heating channel, 5... Exhaust gas outlet, 6... Reforming pipe, 7... Reformed gas inlet, 8... Catalyst layer, 9...
Center tag 2, 10...Return path, 11...Reformed gas outlet, 15...Temperature measuring element, 21...Sleeve pipe, 22...Combustion gas line, 23...Combustion air line , 24... Combustion gas control valve, 26... Combustion air line, 26... Reformed gas line, 27... Reforming pipe lower section, 28... Reformed gas regulating valve, 29...・Pressure measuring gauge, 30...Reformed gas discharge control valve, 3...
・Combustion gas supply amount control valve, 32-...Common line, 3
3... Average temperature calculator, 34, 35.36... Valve controller. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] It has a plurality of reforming tubes each having an annular cross section, one end of which is sealed, and a reforming catalyst layer is provided between an inner pipe line and an outer pipe line, and the combustion gas is combusted in a combustion chamber. The heated fluid obtained by the heating is discharged from one end of the reforming tube through the outside thereof to the outside from the other end, and the reformed gas is introduced from the other end of the reforming tube through the reforming catalyst layer. Further, in the reformer configured to flow from one end of the reformer through the inner pipe line and from the other end, the combustion chamber is configured independently for each reforming tube, and the combustion gas is supplied to each of the combustion chambers. A combustion gas control valve is provided on each of the plurality of combustion gas lines to cause the reformed gas to flow into each of the reforming pipes, and a combustion gas control valve is provided on each of the plurality of reformed gas lines to cause the reformed gas to flow into each of the reforming pipes. a quality gas control valve, a combustion gas supply amount control valve, a temperature measuring element for measuring the tube wall temperature of each of the reforming tubes, and a pressure difference between the reformed gas inlet and outlet of each of the reforming tubes. Compare the average temperature measured by the pressure measuring element that measures the temperature with a predetermined limit temperature, and adjust the supply amount of the combustion gas so that the temperature becomes zero based on the comparison result. a first valve controller for controlling the opening degree of the combustion gas supply amount regulating valve; a second control valve that controls each of the corresponding combustion gas control valves once to adjust the inflow amount of the combustion gas;
The valve controller and the pressure difference measured by each pressure l measuring element are compared with the allowable pressure difference, and the corresponding reformed gas is adjusted to adjust the inflow amount of the reformed gas based on the comparison result. 1. A reforming device comprising: a pipe wall temperature control circuit comprising a third valve controller that separately controls the opening degree of each control valve.