Steam reforming system with improved starting characteristics

Abstract

One embodiment of the present invention provides a steam reforming system including a heat exchange type water gas shift reactor into which raw water flows to generate a first stream, a steam generator into which the first stream flows from the heat exchange type water gas shift reactor to generate a second stream, a mixer into which the second stream flows from the steam generator and into which a raw material gas separately flows to generate a mixed raw material, a superheater into which the mixed raw material flows from the mixer to generate a third stream, and a steam reforming reactor into which the third stream flows from the superheater to generate a reformed gas, the steam reforming system further including an electric heater type evaporator upstream of the steam reforming reactor.

Description

Technical Field

[0001] The present invention relates to a steam reforming system with improved startup characteristics, and more particularly, to a steam reforming system capable of rapid startup through smooth evaporation of steam in the startup step.

Background Art

[0002] A steam reforming reactor is a reactor that produces hydrogen under steam using natural gas mainly composed of methane as a raw material gas. The raw material gas and steam are converted into a reformed gas in which hydrogen, carbon monoxide, and carbon dioxide are mixed on a catalyst. The process of converting to the reformed gas is usually carried out by supplying another reaction heat using a combustion device such as a burner or a catalytic combustor to heat the catalyst layer through a strong endothermic reaction.

[0003] The steam reforming system is configured by the cooperation of a steam generator for evaporating the raw water required for the reaction and a reaction raw material preheater containing the raw material gas and steam for the entire process. Here, the heat required for the steam generator and the preheater can be supplied by recovering the waste heat from the combustion exhaust gas discharged by heating the catalyst layer or the reformed gas produced.

[0004] Conventionally, when rapid startup, stop, and load fluctuation response characteristics are required in a steam reforming system, a once-through boiler method is applied, which is composed of only a single tube without a steam drum, and the raw water supplied by a feed water pump generates steam while passing through a preheating section, an evaporation section, and a superheating section in sequence.

[0005] The once-through boiler system allows for a free tube arrangement, facilitates the compactification of the entire device, and has a very small water inventory per unit heat transfer area, resulting in a short time required to generate the necessary steam. However, due to large fluctuations in pressure and water inventory with load variations, unevaporated raw water and steam are both introduced into the steam reforming reactor during startup and load change steps, leading to problems such as a decrease in process stability, catalyst damage, or a time delay for drying the catalyst layer wetted by moisture.

[0006] When continuously increasing the output of a combustion device such as a burner or a catalytic combustor for rapid startup, the steam reforming catalyst layer where direct heat exchange with the combustion device occurs may overheat above the appropriate temperature, potentially causing thermal damage to the catalyst. Therefore, there is a limit to the output of the combustion device during startup operation.

[0007] Therefore, there is a need for a steam reforming system that can achieve rapid startup through smooth evaporation of steam and solve the above problems during the startup step of the steam reforming reactor.

Summary of the Invention

Problems to be Solved by the Invention

[0008] An object of the present invention is to provide a steam reforming system capable of rapid startup through smooth evaporation of steam during the startup step.

[0009] Another object of the present invention is to provide a steam reforming system that can stably perform the steam reforming process by preventing the introduction of liquid raw water into the steam reforming reactor during the startup step and load change steps, thereby preventing side reactions or catalyst damage.

[0010] Still another object of the present invention is to provide an electric heater type evaporator that can significantly shorten the startup time by optimizing the heat contact area and maximizing the evaporation efficiency, and a steam reforming system including the same.

[0011] Moreover, the technical problems to be solved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by those with ordinary knowledge in the technical field to which the present invention belongs from the following description.

Means for Solving the Problems

[0012] The present invention is derived to solve the above problems. One embodiment of the present invention includes a heat exchange type water gas shift reactor into which raw water flows and a first stream is generated, a steam generator into which the first stream flows from the heat exchange type water gas shift reactor and a second stream is generated, a mixer into which the second stream flows from the steam generator and raw gas separately flows and a mixed raw material is generated, a superheater into which the mixed raw material flows from the mixer and a third stream is generated, and a steam reforming reactor into which the third stream flows from the superheater and reformed gas is generated. A steam reforming system is provided, which further includes an electric heater type evaporator in front of the steam reforming reactor.

[0013] In one embodiment, the electric heater type evaporator can be included between the steam generator and the mixer.

[0014] In one embodiment, the second stream flows from the steam generator into the electric heater type evaporator and a 2-1 stream is generated, and the 2-1 stream can flow from the electric heater type evaporator into the mixer.

[0015] In one embodiment, the reformed gas generated in the steam reforming reactor is cooled while passing through the steam generator and the water gas shift reactor in sequence, and the raw water can be configured to be vaporized by heat exchange with the reformed gas.

[0016] In one embodiment, the electric heater type evaporator includes a metal tube extending in the longitudinal direction, and the metal tube has a supply port formed at the upper or lower part and a discharge port formed at one side part, and at least one or more U-shaped heater pipes parallel to the longitudinal direction of the metal tube can be included inside the metal tube.

[0017] In one embodiment, the electric heater type evaporator includes a plurality of baffle plates extending in the thickness direction inside the metal tube, and each of the plurality of baffle plates can be arranged at intervals.

[0018] In one embodiment, each of the plurality of baffle plates can be alternately arranged at intervals in sequence on the upper and lower parts of the metal tube in the direction from the supply port to the discharge port of the metal tube.

[0019] In one embodiment, each of the plurality of baffle plates can be alternately arranged at intervals in sequence on the lower and upper parts of the metal tube in the direction from the supply port to the discharge port of the metal tube.

[0020] In one embodiment, the interval between each of the plurality of baffle plates being separated may be 1 / 9L to 4 / 9L of the length L of the metal tube.

[0021] In one embodiment, the electric heater type evaporator can include a porous heat transfer filler inside the metal tube.

[0022] In one embodiment, the porous heat transfer filler can be buffered inside the metal tube.

[0023] In one embodiment, the porous heat transfer filler can be located in a separated region in the direction from the supply port to the discharge port of the metal tube.

[0024] In one embodiment, the interval between the regions where the porous heat transfer filler is located being separated may be 1 / 9L to 3 / 9L of the length L of the metal tube.

[0025] In one embodiment, the electric heater type evaporator can include an injection nozzle at the end of the supply port.

Advantages of the Invention

[0026] The steam reforming system according to the present invention has the advantage that in the startup step, smooth evaporation of steam enables rapid startup.

[0027] The steam reforming system according to one embodiment of the present invention prevents liquid raw water from being introduced into the steam reforming reactor in the startup step and the load fluctuation step, and by preventing side reactions or damage to the catalyst, the steam reforming process can be stably carried out.

[0028] The steam reforming system according to the present invention has the advantage that by preventing liquid raw water from being introduced into the steam reforming reactor and preventing side reactions or damage to the catalyst, the steam reforming process can be stably carried out.

[0029] The electric heater type evaporator according to the present invention and the steam reforming system including the same can significantly shorten the startup time by optimizing the heat contact efficiency and maximizing the steam evaporation efficiency.

Brief Description of the Drawings

[0030]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0031] The singular forms of the terms used in this specification can be interpreted to include the plural forms as well, unless otherwise indicated.

[0032] The “including” mentioned in this specification is an open-ended description having the same meaning as expressions such as “comprising,” “containing,” “having,” “characterized by,” etc., and does not exclude elements, materials, or steps not further listed.

[0033] The numerical ranges used in this specification include the lower limit value and the upper limit value, all values within that range, all limited values among them, and all possible combinations of the upper and lower limits of the numerically limited ranges different from each other. Unless otherwise specifically defined in this specification, values outside the numerical ranges that may occur due to experimental errors or rounding of values are also included in the defined numerical ranges.

[0034] The stream mentioned in this specification means including unevaporated raw water and water vapor, unless otherwise specifically defined.

[0035] Unless otherwise defined, all technical terms and scientific terms have the same meaning as generally understood by one of ordinary skill in the technical field to which the present invention pertains. The terms used in the description of this application are merely for effectively describing specific examples and are not intended to limit the present invention.

[0036] Hereinafter, with reference to the drawings and embodiments, the steam reforming system according to the present invention will be described in more detail. However, the following embodiments or implementation forms are one reference for explaining the present invention in detail, and the present invention is not limited thereto and may be realized in various forms.

[0037] Conventionally, in a steam reforming system, when rapid startup, shutdown, and load change response characteristics are required, a once-through boiler system is applied, which consists of only a single tube without a steam drum, and the raw water supplied by a feed water pump generates steam while passing through a preheating section, an evaporation section, and a superheating section in sequence.

[0038] Since the once-through boiler system allows for a free tube arrangement, it is easy to compact the entire device. Also, because the water inventory per unit heat transfer area is very small, the time required to generate the required steam is short. However, due to large fluctuations in pressure and water inventory with load changes, during startup and load change steps, unevaporated raw water and steam are both introduced into the steam reforming reactor, which can cause fatal problems such as a decrease in process stability, catalyst damage, or a delay in startup time to redry the catalyst layer wetted by moisture.

[0039] When continuously increasing the output of a combustion device such as a burner or a catalytic combustor for rapid startup, the steam reforming catalyst layer that undergoes direct heat exchange with the combustion device may overheat above the appropriate temperature, resulting in thermal damage to the catalyst. Therefore, there is a limit to the output of the combustion device during startup.

[0040] Accordingly, an object of the present invention is to provide a steam reforming system that can significantly shorten the startup time and solve problems such as a decrease in stability, catalyst damage, or a delay in startup time.

[0041] One embodiment of the present invention provides a steam reforming system including a heat exchange type water gas shift reactor 3 into which raw water flows and a first stream is generated, a steam generator 4 into which the first stream flows from the heat exchange type water gas shift reactor 3 and a second stream is generated, a mixer 7 into which the second stream flows from the steam generator 4 and raw gas separately flows to generate a mixed raw material, a super heater 8 into which the mixed raw material flows from the mixer and a third stream is generated, and a steam reforming reactor 10 into which the third stream flows from the super heater and reformed gas is generated, and further includes an electric heater type evaporator 13 in the front stage of the steam reforming reactor 10. By further including the electric heater type evaporator 13 in the front stage of the steam reforming reactor 10, further evaporation can be induced even under a low heat input condition due to load fluctuation, preventing the inflow of unevaporated raw water into the steam reforming reactor 10 and solving problems such as catalyst damage or startup time delay. Also, as will be described later, by including the electric heater type evaporator 13 having a structure capable of maximizing the heat transfer area, the startup time can be significantly shortened.

[0042] FIG. 2 illustrates a conventional steam reforming system. Conventionally, the steam reforming system includes a raw water preheater 1, a heat exchange type water gas shift reactor 3, a steam generator 4, a mixer 7, a super heater 8, and a steam reforming reactor 10. The heating furnace 11 includes the steam reforming reactor 10 and a burner 12. Burner fuel and air flow into the burner 12, and the burner 12 can be gradually heated along with load fluctuation to supply heat to the steam reforming reactor 10. The means for supplying the heat can be used without limitation as long as it can supply heat other than the burner 12. Inside the steam reforming reactor 10, a steam reforming catalyst is included. By introducing raw gas and steam into the steam reforming reactor 10, reformed gas containing hydrogen can be generated by a reforming reaction.

[0043] Table 1 below shows the results when, in a conventional steam reforming system, the maximum heat amount at the burner 12 was supplied by supplying raw water and raw gas up to 100% of the maximum load. When specifically analyzing the stream (product) generated during the process of vaporizing the raw water, it is as shown in Table 1 below.

[0044]

Table 1

[0045] Referring to Table 1 above, the preheated raw water discharged from the raw water preheater 1 has not yet evaporated at a pressure of 16 bar.G and a temperature of 160°C, and only raw water exists. The preheated raw water begins to evaporate while passing through the heat exchange type water gas shift reactor 3. The ratio of water vapor in the first stream discharged from the heat exchange type water gas shift reactor 3 increases to 0.1, and the ratio of water vapor in the second stream discharged from the water vapor generator 4 increases to 0.6. The second stream discharged from the water vapor generator 4 is mixed with the raw gas separately flowing in from the mixer 7 to generate a mixed raw material. Due to phase equilibrium, the ratio of water vapor in the mixed raw material temporarily decreases to 0.5. The mixed raw material discharged from the mixer 7 is heated in the superheater 8, and the ratio of water vapor in the third stream discharged from the superheater can be completely vaporized to 1. The completely vaporized stream is heated at about 400 - 500°C and introduced into the steam reforming reactor 10 to carry out the reforming reaction.

[0046] However, during the startup operation of the conventional steam reforming system, in the evaporation processes in the heat exchange type water gas shift reactor 3 and the steam generator 4, since only the waste heat of the reformed gas is utilized, there may be intervals where the amount of heat required for the evaporation of the raw water is insufficient or not supplied smoothly. The specific reasons are as follows. During the startup operation of the steam reforming system, first, while supplying an inert gas such as nitrogen as a purge gas instead of the raw material gas, the burner 12 is gradually operated, and the steam reforming catalyst layer 9 in the steam reforming reactor 10 and the heat exchange type water gas shift reactor 3 are heated up to near the actual operating temperature. First, raw water with a flow rate corresponding to a load of 50% or less is supplied to the feed water pump, and steam is generated by heat exchange with the purge gas. After the generated steam sufficiently passes through the steam reforming catalyst layer 9 and the heat exchange type water gas shift reactor 3, raw material gas with a flow rate corresponding to a load of 50% or less is supplied and converted into reformed gas by the reaction. Thereafter, steam is generated by heat exchange between the generated reformed gas and the raw water. When smooth steam generation is achieved, the purge gas is stopped, and the supply amounts of the raw material gas and the raw water are gradually increased and supplied up to the maximum load of 100% to complete the startup. Here, in the heat exchange type water gas shift reactor 3 or the steam generator 4, the heat exchange efficiency varies depending on the load fluctuation and the amount of heat supplied from the burner 12. As described above, at a load of 50% or less, the heat exchange efficiency is extremely reduced, smooth evaporation of the raw water does not occur, unevaporated raw water remains, and various problems described above may occur.

[0047] Therefore, in one embodiment of the present invention, by providing an electric heater type evaporator 13 in the front stage of the steam reforming reactor 10, even under low heat input conditions due to load fluctuations, further evaporation of the raw water can be induced, so that the startup time can be shortened, and the inflow of unevaporated raw water into the steam reforming reactor 10 can be prevented. In addition, the startup time can be shortened without continuously increasing the output of a combustion device such as a burner or a catalytic combustor, and thermal damage to the catalyst can be prevented.

[0048] In one embodiment, the electric heater type evaporator 13 can be included between the steam generator 4 and the mixer. Referring to FIG. 1, by providing the electric heater type evaporator 13 upstream of the mixer 7 into which the raw material gas is mixed, side reactions or risks caused by the combustible raw material gas can be prevented. By installing it downstream of the steam generator 4 and immediately compensating for the insufficient supply heat quantity in the heat exchange type water gas shift reactor 3 and the steam generator 4 due to load fluctuations, the process efficiency and startup characteristics can be effectively improved.

[0049] In one embodiment, a second stream may flow from the steam generator 4 into the electric heater type evaporator 13 to generate a 2-1 stream, and the 2-1 stream may flow from the electric heater type evaporator 13 into the mixer. By providing the electric heater type evaporator 13 between the steam generator 4 and the mixer, the second stream flows from the steam generator 4 into the electric heater type evaporator 13, and further evaporation occurs.

[0050] The heat capacity of the electric heater type evaporator 13 may be at least 2% or more of the total input heat quantity supplied from at least the burner 12. This is the minimum capacity capable of substituting for the insufficient heat quantity in the heat exchange type water gas shift reactor 3 or the steam generator 4 at the initial startup of the steam reforming system according to one embodiment of the present invention. Specifically, the heat capacity of the electric heater type evaporator 13 may be at least 4% or more of the total input heat quantity supplied from at least the burner 12, more specifically, it may be 5% or more, and non-limitingly, it may be 20% or less.

[0051] In one embodiment, the reformed gas generated in the steam reformer 10 is cooled while passing through the steam generator 4 and the heat exchange type water gas shift reactor 3 in sequence. Here, the raw material water can be vaporized by heat exchange. As described above, the raw material water can be gradually vaporized by heat exchange between the waste heat of the reformed gas and the raw material water. The raw material water can flow into and be preheated in the raw material water preheater 1 before flowing into the heat exchange type water gas shift reactor 3. The preheated raw material water can flow into the heat exchange type water gas shift reactor 3 and the steam generator 4 in sequence, and the raw material water can be gradually vaporized by heat exchange between the waste heat of the reformed gas and the raw material water. Not only the heat exchange type water gas shift reactor 3 but also the raw material water preheater 1 and the steam generator 4 can have heat exchange performance.

[0052] A detailed description of the electric heater type evaporator 13 is as follows.

[0053] In one embodiment, the electric heater type evaporator 13 includes a metal tube extending in the longitudinal direction. The metal tube has a supply port formed at the upper or lower part and a discharge port formed at one side part. The inside of the metal tube can include at least one or more U-shaped heater pipes parallel to the longitudinal direction of the metal tube.

[0054] FIGS. 4 to 6 are diagrams showing cross-sectional views in the longitudinal direction of the electric heater type evaporator 13 according to an embodiment of the present invention. A supply port 20 is formed at the upper part 22 or the lower part 23 of the metal tube, and a discharge port 21 is formed at one side part. The inside of the metal tube can include at least one or more U-shaped heater pipes 25 parallel to the longitudinal direction of the metal tube. The metal tube can extend in the longitudinal direction. Here, the length L of the metal tube may be 3H to 10H of the height H of the metal tube. Specifically, it may be 3H to 8H. This is an example and is not necessarily limited thereto.

[0055] In one embodiment, the supply port 20 may be formed in the upper part 22 or the lower part 23 of the metal pipe. Referring to FIG. 4, an electric heater type evaporator 13 with the supply port 20 formed in the upper part 22 of the metal pipe is illustrated. A second stream containing unevaporated raw water and water vapor can flow into the interior of the metal pipe through the supply port 20, and further evaporation can be induced by at least one or more U-shaped heater pipes 25 parallel to the longitudinal direction of the metal pipe contained inside the metal pipe.

[0056] In one embodiment, the longitudinal end of the upper part 22 of the metal pipe can be inclined and bent toward the lower part 23. In this way, an outlet 21 is formed between the upper part 22 and the lower part 23 that are inclined and bent toward the lower part 23 of the metal pipe and opened at one side end of the metal pipe, so that the product (second - 1 stream) can be efficiently discharged. Here, the bent shape of the end of the upper part 22 of the metal pipe may be curved, but is not necessarily limited to this. On the other hand, since there is no other outlet 21 except the outlet 21, the product (second - 1 stream) subjected to the evaporation treatment by the heater pipe 25 is completely discharged from the outlet 21 and can flow into the total mixer 7.

[0057] In one embodiment, the electric heater type evaporator 13 includes a plurality of baffle plates extending in the thickness direction inside the metal pipe, and each of the plurality of baffle plates may be arranged at intervals. Referring to FIG. 4, when evaporating the second stream flowing into the supply port 20 of the electric heater type evaporator 13, by including a plurality of baffle plates 24 extending in the thickness direction inside the metal pipe, the heat contact area with the heater pipe 25 can be improved, and an excellent evaporation effect can be realized. When the baffle plates 24 are not included, the raw water flowing into the interior of the metal pipe only contacts a part of the heater pipe 25 located toward the lower part 23 of the metal pipe, so efficient evaporation cannot be induced.

[0058] In one embodiment, each of the plurality of baffle plates may be alternately and spaced apart in order on the upper and lower portions of the metal tube in the direction from the supply port to the discharge port of the metal tube.

[0059] In one embodiment, each of the plurality of baffle plates may be alternately and spaced apart in order on the lower and upper portions of the metal tube in the direction from the supply port to the discharge port of the metal tube.

[0060] When the plurality of baffle plates 24 are alternately and spaced apart, as described above, they may be arranged in the order of upper part 22 - lower part 23 - upper part 22 in the direction from the supply port to the discharge port of the metal tube, or, as shown in FIG. 4, in the order of lower part 23 - upper part 22 - lower part 23 in the direction from the supply port to the discharge port of the metal tube. In such a case, the second stream flowing into the supply port is guided by the plurality of baffle plates 24 as described above, contacts the entire heater pipe 25, and by improving the heat contact area and contact time, an excellent evaporation effect can be realized, and the startup time can be significantly shortened. Here, the angle at which each baffle plate 24 is located is preferably formed perpendicular to the longitudinal direction of the metal tube.

[0061] In one embodiment, the interval between each of the plurality of baffle plates being separated may be 1 / 9L to 4 / 9L of the length L of the metal tube. When separated at an interval of 1 / 9L to 4 / 9L of the length L of the metal tube, the heat contact area can be maximized, and preferably, it can be separated at an interval of 1 / 9L to 3 / 9L. By adjusting the interval, the number and arrangement structure of the baffle plates 24, etc. can be optimized. The interval between each of the plurality of baffle plates being separated may be 1 / 9L to 4 / 9L of the length L of the metal tube, but is not necessarily limited thereto.

[0062] In one embodiment, the plurality of baffle plates 24 can be positioned at intervals of 1 / 9L to 4 / 9L from the supply port. By being positioned at such intervals from the supply port, smooth movement of the second stream containing unevaporated raw material water and water vapor flowing into the supply port can be induced. The plurality of baffle plates 24 can be positioned at intervals of 1 / 9L to 4 / 9L from the supply port, but is not necessarily limited thereto.

[0063] In one embodiment, the height of the plurality of baffle plates 24 may be 1 / 6H to 4 / 6H of the height H of the metal tube. In this case, the heat contact area can be maximized. Specifically, it may be 1 / 6H to 3 / 6H, and is not necessarily limited thereto.

[0064] In one embodiment, the heights of the plurality of baffle plates 24 may all be the same. It is not necessarily limited thereto. In another embodiment, the heights of the plurality of baffle plates 24 can gradually decrease in the direction from the supply port 20 to the discharge port 21. In this case, smooth movement of the second stream containing unevaporated raw material water and water vapor can be further induced.

[0065] In one embodiment, the material of the baffle plate 24 is not limited as long as it does not deform due to thermal expansion or corrode due to oxidation at high temperatures, but it may be a metal or ceramic material.

[0066] In one embodiment, the electric heater type evaporator 13 can include a porous heat transfer filler 26 inside the metal tube. By including the porous heat transfer filler 26, smoother movement of the second stream flowing into the supply port can be further induced, and the heat contact area can be improved. That is, by including the porous heat transfer filler 26, the evaporation efficiency of the electric heater type evaporator 13 can be maximized. The porous heat transfer filler 26 can include a conventionally known porous heat transfer filler 26, and can include, for example, those selected from the group consisting of alumina, aluminum, iron, copper, graphene, carbon nanotubes, carbon black, graphite, carbon fibers, and combinations thereof. Preferably, the porous heat transfer filler 26 may be alumina.

[0067] In one embodiment, the porous heat transfer filler may be buffered inside the metal tube. As shown in FIG. 4, the porous heat transfer filler 26 is filled and buffered throughout the inside of the metal tube, and smooth movement of the second stream can be induced in all regions of the lower and upper parts of the metal tube, and the heat contact area can be improved.

[0068] In one embodiment, the porous heat transfer filler can be located in a region spaced in the direction from the supply port to the discharge port of the metal tube.

[0069] In one embodiment, the spaced interval of the region where the porous heat transfer filler is located may be 2 / 9L to 5 / 9L of the length L of the metal tube. As will be described later, the electric heater type evaporator 13 can include an injection nozzle at the end of the supply port. As shown in FIG. 6, it can be located in a predetermined region spaced from the supply port 20. When spaced from the supply port 20 by the interval, the initial contact area from the injection nozzle can be maximized, and a uniform evaporation effect can be induced.

[0070] In one embodiment, the electric heater type evaporator 13 can include an injection nozzle 29 at the end of the supply port 20. As shown in FIG. 6, by using the injection nozzle 29 formed at the end of the supply port 20 to inject raw water and steam toward the porous heat transfer filler 26, the initial contact area can be maximized, and a uniform evaporation effect can be induced.

[0071] That is, as described above, the present invention provides a steam reforming system including an electric heater type evaporator 13 having a structure with a maximized heat contact area, thereby significantly shortening the startup time and supplementing and supplying the insufficient heat amount required for the evaporation of raw water due to load fluctuations, so as to induce smooth evaporation and prevent unevaporated raw water from flowing into the steam reforming reactor 10.

[0072] Hereinafter, with reference to FIG. 1, a steam reforming system according to an embodiment of the present invention will be described in detail.

[0073] The steam reforming reactor 10 can include a catalyst layer 9 filled with a reforming catalyst. The type of the reforming catalyst is not particularly limited, and it can include any one or more selected from the group consisting of one or more metals selected from gold, silver, iron, cobalt, nickel, copper, manganese, aluminum, zinc, titanium, hafnium, platinum, rhodium, ruthenium, osmium, iridium, palladium, zirconium, and lanthanum group metals, or oxides and composites thereof.

[0074] In the steam reforming reactor 10, the reforming reaction can involve a reaction as shown in the following reaction formula 1.

[0075] [Reaction formula 1] CH4 + H2O → 3H2

[0076] Here, the reaction temperature is 500 to 900 °C, preferably 600 to 850 °C, and the reaction pressure may be in the range of 0.2 to 2.5 MPaG, preferably 1.2 to 2.0 MPaG. This is a non-limiting example and is not limited to the above numerical range. The reforming reaction can be carried out by supplying heat with the burner 12. Here, heat can be supplied while gradually increasing the temperature of the burner 12.

[0077] The combustion exhaust gas discharged from the steam reformer 10 can evaporate and superheat the unevaporated raw material water by heat exchange between the waste heat of the combustion exhaust gas and the mixed raw materials in the superheater 8 while passing through the superheater 8.

[0078] The reformed gas generated in the steam reformer 10 can be cooled while passing through the steam generator 4 and the heat exchange type water gas shift reactor 3 in sequence. In the heat exchange type water gas shift reactor 3 filled with the water gas shift reaction catalyst 2, the water gas shift reaction of the following reaction formula 2 occurs, and a reformed gas rich in hydrogen can be obtained.

[0079] [Reaction formula 2] CO + H2O → CO2 + H2

[0080] In one embodiment, the steam reforming system further includes a raw material water preheater 1, and the raw material water can flow into the raw material water preheater 1 before flowing into the heat exchange type water gas shift reactor 3.

[0081] In one embodiment, the steam reforming system further includes a desulfurizer 6, and the raw material gas can flow into the desulfurizer 6 before flowing into the mixer 7. In order to obtain a high-quality reformed gas with a high hydrogen yield from the raw material gas (such as natural gas, LPG), the desulfurization process can be carried out by flowing the raw material gas into the desulfurizer 6 filled with the adsorption type desulfurization agent 5 before flowing into the mixer 7.

[0082] The above has described one embodiment of the present invention including the drawings. However, the present invention is not limited to the above embodiment and may be implemented in various different forms. Those having ordinary knowledge in the technical field to which the present invention pertains can understand that it can be implemented in other specific forms without changing the technical idea and essential features of the present invention. Therefore, it should be understood that the above-described embodiments and implementations are illustrative in all aspects and not restrictive.

Explanation of Signs

[0083] 1 Raw water preheater 2 Water gas shift reaction catalyst 3 Heat exchange type water gas shift reactor 4 Steam generator 5 Adsorption type desulfurization unit 6 Desulfurizer 7 Mixer 8 Super heater 9 Steam reforming catalyst layer 10 Steam reforming reactor 11 Heating furnace 12 Burner 13 Electric heater type evaporator 20 Supply port 21 Discharge port 22 Upper part of metal tube 23 Lower part of metal tube 24 Baffle plate 25 Heater pipe 26 Porous heat transfer filler 27 Insulation part 28 Connection terminal 29 Injection nozzle L Length of metal tube H Height of metal tube

Claims

1. A steam reforming system including a heat exchange type water gas shift reactor into which raw material water flows to generate a first stream, a steam generator into which the first stream flows from the heat exchange type water gas shift reactor to generate a second stream, a mixer into which the second stream flows from the steam generator and into which a raw material gas separately flows to generate a mixed raw material, a superheater into which the mixed raw material flows from the mixer to generate a third stream, and a steam reforming reactor into which the third stream flows from the superheater to generate a reformed gas, The steam reforming system including an electric heater type evaporator in front of the steam reforming reactor.

2. The steam reforming system according to claim 1, wherein the electric heater type evaporator is included between the steam generator and the mixer.

3. The steam reforming system according to claim 2, wherein the second stream flows from the steam generator into the electric heater type evaporator to generate a second - 1 stream, and the second - 1 stream flows from the electric heater type evaporator into the mixer.

4. The steam reforming system according to claim 1, wherein the reformed gas generated in the steam reforming reactor is cooled while passing through the steam generator and the water gas shift reactor in sequence, and the raw material water is configured to be vaporized by heat exchange with the reformed gas.

5. The steam reforming system according to claim 1, wherein the electric heater type evaporator includes a metal tube extending in the longitudinal direction, the metal tube is formed with a supply port at the upper or lower part and a discharge port at one side part, and the inside of the metal tube includes at least one or more U - shaped heater pipes parallel to the longitudinal direction of the metal tube.

6. The steam reforming system according to claim 5, wherein the electric heater type evaporator includes a plurality of baffle plates extending in the thickness direction inside the metal tube, and each of the plurality of baffle plates is arranged separately.

7. For each of the plurality of baffle plates, they are alternately and spaced apart in sequence at the upper and lower parts of the metal tube in the direction from the supply port to the discharge port of the metal tube. The steam reforming system according to claim 6.

8. For each of the plurality of baffle plates, they are alternately and spaced apart in sequence at the lower and upper parts of the metal tube in the direction from the supply port to the discharge port of the metal tube. The steam reforming system according to claim 6.

9. The interval at which each of the plurality of baffle plates is spaced apart is 1 / 9L to 4 / 9L of the length L of the metal tube. The steam reforming system according to claim 6.

10. The electric heater type evaporator includes a porous heat transfer filler inside the metal tube. The steam reforming system according to claim 5.

11. The porous heat transfer filler is buffered inside the metal tube. The steam reforming system according to claim 10.

12. The porous heat transfer filler is located in a region spaced apart in the direction from the supply port to the discharge port of the metal tube. The steam reforming system according to claim 10.

13. The interval at which the region where the porous heat transfer filler is located is spaced apart is 2 / 9L to 5 / 9L of the length L of the metal tube. The steam reforming system according to claim 12.

14. The electric heater type evaporator includes an injection nozzle at the end of the supply port. The steam reforming system according to claim 5.

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