Abstract:
The invention discloses residual gas heat exchange combustion-supporting system based on a methanol-water mixture reforming hydrogen production system and a method thereof, wherein the residual gas heat exchange combustion-supporting system comprises a reformer, a heat exchange tube and an air intake device: the reformer is provided with a reforming chamber, a separating device, a combustion chamber and an exhaust vent, the residual gas produced by the reformer is discharged from the exhaust vent to the first delivery passage of the heat exchange, tube; the heat exchange tube has coaxial double-layer first and second delivery passages. The invention enables to fully reclaim the heat from the residual gas discharged by the reformer, so that the outside air is warmed before entering the reformer, which in turn makes the warmed outside air attain a very good combustion-supporting effect.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of International Patent Application No. PCT/CN2016/083485 with a filing date of May 26, 2016, designating the United States, now pending, and further claims priority to Chinese Patent Application No. 201510300749.2 with a filing date of Jun. 05, 2015. The content of the aforementioned application, including any intervening amendments thereto, are incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to the technical field of hydrogen production from methanol-water mixture reforming, and particularly to residual gas heat exchange combustion-supporting system based on a methanol-water mixture reforming hydrogen production system and a method thereof. 
       BACKGROUND OF THE PRESENT INVENTION 
       [0003]    Hydrogen is one of the most desirable energies of the 21st century, which produces the most energy under the circumstances that a same amount of coal, gasoline, and hydrogen is being burned. The final product from combustion of the hydrogen is water without ash and exhaust gases causing environment pollution; while CO2 and SO2 are primary products from combustion of coal and petroleum which respectively lead to greenhouse effect and acid rain. Coal and petroleum reserves are limited, and the hydrogen primarily exists in water, the only product from combustion is water continuing to produce hydrogen which will never be used up. Hydrogen is widely distributed, and water is a large “warehouse” of the hydrogen, which contains 11% of hydrogen. There is about 1.5% of the hydrogen in the soil; petroleum, coal, natural gas, animal and plant body and the like all contain hydrogen. Hydrogen is mainly in form of compound water, and about 70% of the Earth&#39;s surface is covered by water, water storage capacity is large, it can be said therefore that hydrogen is an “inexhaustible” energy. If hydrogen can be produced in a suitable way, then hydrogen will also be a rather cheap energy source. 
         [0004]    At present, the world&#39;s annual output of the hydrogen is about 36 million tons, there are two primary hydrogen production methods: one of which is that the vast majority of the hydrogen is prepared from the petroleum, coal and natural, gas, and this method needs to consume originally scarce fossil fuels; the other of which is about 4% of the hydrogen is prepared by electrolysis of water, and this method consumes large power and is not economical. With the development of the technology, the technology of hydrogen production from methanol-water mixture reforming is gradually developed, which can reduce the energy consumption and reduce the cost of chemical production, and is expected to replace the water-electrolytic hydrogen production technology of which electricity consumption is particular high. Advanced methanol-steam reforming technology is used to produce a mixed gas of H2 and CO2, and is then separated by a palladium membrane separator to obtain H2 and CO2 respectively. 
         [0005]    With reference to a Chinese application for a patent for invention 201310340475.0 (with the applicant being Shanghai Hejide Dynamic Hydrogen Machine Co., Ltd.), the invention discloses a methanol-water mixture hydrogen production system, wherein the methanol and the steam are subjected to methanol cracking reaction and carbon monoxide conversion reaction in the reforming chamber of the reformer at a temperature of 350-570° C. and a pressure of 1-5 MPa in the presence and under the effect of a catalyst to generate hydrogen and carbon dioxide, and the system is a multi-component and multi-reaction gas-solid catalytic reaction system. The reaction equations are as follows: (1) CH3OH→CO+2H2; (2) H2O+CO→CO2+H2; (3) CH3OH+H2O→CO2+3H2 the H2 and CO2 produced from the reforming reaction then separates H2 and CO2 by the palladium membrane separator in the separation chamber to obtain high-purity hydrogen. 
         [0006]    During the process of hydrogen production from methanol-water mixture reforming, due to the fact that a temperature of 350-570° C. needs to be maintained in the reformer, after the reformer is started, part of the generated H2 needs to be in combustion with O2 to generate heat to maintain the operation of, the reformer. In the prior art, O2 is directly derived from the air fanned from the outside into the reformer, specifically referring to the Chinese invention application 201410311217.4 (Applicant: Guangdong Hejide Energy Technology Co., Ltd.), the reformer is equipped with an air inlet cover plate which is provided with an air duct through which the outside air can enter the reformer. The reformer is equipped with an exhaust device (air cylinder), the N2, CO2 and other unburned gases in the outside air, as well as the water vapor generated from combustion of O2 and H2 are all discharged from the exhaust device (air cylinder) at the same time, the H2 and CO2 produced from the methanol-water mixture reforming reaction are separated out the hydrogen by the palladium membrane separator in the separation chamber, and the remaining CO2 and the unreacted water vapor are also discharged from the exhaust device (air cylinder). These exhaust gases (including, water vapor, CO2, N2 and other gases) have the characteristics of being oxygen-deficient, water vapor-rich, and high-heat and the temperature thereof is usually between 300-600° C. 
         [0007]    In view of the above, based on the above technical conditions, the defects are: firstly, the discharged residual gases have wasted a lot of heat, making the utilization ratio of the methanol-water mixture feedstock for the methanol-water mixture reforming hydrogen production system being not high, which is not conducive to energy conservation and emission reduction; secondly, the discharged residual gases have high temperature (usually 300-600° C.), which has an, impact on the operation of each component of the methanol-water mixture reforming hydrogen production system, such, as when the control device is affected by the high temperature gas, its life and stability will be significantly reduced, or even there will be serious burnout problems; thirdly, the O2 required for combustion in the reformer is directly derived from the air fanned from the outside into the reformer, the air temperature is room temperature, and after the room temperature air directly enters the reformer, its combustion-supporting effect is not good. 
       SUMMARY OF PRESENT INVENTION 
       [0008]    A technical problem to be solved by the present invention is to provide residual gas heat exchange combustion-supporting system based on a methanol-water mixture reforming hydrogen production system for over the deficiencies in the prior art, and the residual gas heat exchange combustion-supporting system is capable of fully reclaiming the heat of the residual gas discharged by the reformer, so that the outside air with a raised temperature has an extremely good combustion-supporting effect. The present invention also provides a method of the residual gas heat exchange combustion-supporting system. 
         [0009]    In order to solve the above-mentioned, first technical problem, the technical solution of the invention is that: 
         [0010]    residual gas heat exchange combustion-supporting system based on a methanol-water mixture reforming hydrogen production system, comprising a reformer, a heat exchange tube and an air intake device, wherein: 
         [0011]    the reformer, which is provided with a reforming chamber used for producing a mixed gas of hydrogen and carbon dioxide from a reforming reaction for hydrogen production between methanol and steam, a separating device used for separating the produced hydrogen out, a combustion chamber used for combustion of part of the produced hydrogen with the oxygen in the outside air to provide heat for the operation of the reformer, and an exhaust vent; the carbon dioxide separated out by the separating device, the water vapor generated by combustion of the hydrogen and the oxygen in the combustion chamber and the unburned gas in the outside air are mixed into residual gas which will be discharged from the exhaust vent to the first delivery passage of the heat exchange tube; 
         [0012]    the heat exchange tube, having coaxial double-layer delivery passages, i.e., first and second delivery passages, at one end of the heat exchange tube, the first delivery passage is communicated with the exhaust vent, and the second delivery passage is communicated with the, air inlet of the combustion chamber of the reformer; at the other end of the heat exchange tube, the first delivery passage is provided with residual gas outlet, and the second delivery passage is connected with the air intake device; the outside air input by the air intake device in the second delivery passage exchanges heat with the residual gas in the first delivery passage, the outside air with a raised temperature enters the combustion chamber of the reformer for supporting combustion, and the residual gas with a lowered temperature is discharged from the residual gas outlet of the first delivery passage, 
         [0013]    The residual gas heat exchange combustion-supporting system based on a methanol-water mixture reforming hydrogen production system is further provided with a gas-water separator which comprises a gas-water separator body, and a gas-water inlet, an air outlet and a water outlet provided on the gas-water separator body, wherein the gas-water inlet is communicated with the residual gas outlet of the first delivery passage, and the air outlet is connected with an exhaust fan. 
         [0014]    The water outlet of the water-gas separator is connected with a water purifier in which an RO-membrane water purifying device is provided, and the water purified by the water purifier is output to the water purification tank. 
         [0015]    The residual gas heat exchange combustion-supporting system based on a methanol-water mixture reforming hydrogen production system further comprises a methanol-water mixture storage and delivery device including, methanol-water mixture storage vessel and a delivery pump, the methanol-water mixture storage vessel is stored with liquid methanol and water feedstock, and the delivery pump is used for delivering the methanol and mater feedstock stored in the methanol-water mixture storage vessel to the reformer; the water output by the gas-water separator or the water output by the water purification tank is supplied to the methanol-water mixture storage vessel as a water feedstock. 
         [0016]    A heat exchanger is provided on the delivery line between the methanol-water mixture storage and delivery device and the reformer, a low-temperature methanol and water feedstock exchanges heat with the high-temperature hydrogen output from the reforming chamber in the heat exchanger, and the methanol and water feedstock is warmed and vaporized; the hydrogen output from the gas producing end of the separating device is cooled by the heat exchanger. 
         [0017]    The heat exchange tube is wound helically around a shell of the reformer, the upper end of the heat exchange tube is one end communicating the exhaust vent of the reformer with the air inlet of the combustion chamber of the reformer, and the lower end of the heat exchange tube is one end connecting an air intake device with residual gas outlet. 
         [0018]    The heat exchange tube is any one of a coaxial double-layer titanium alloy corrugated pipe, a coaxial double-layer magnesium alloy corrugated pipe, a coaxial double-layer aluminum corrugated pipe, a coaxial double-layer copper corrugated pipe, and a coaxial double-layer stainless steel corrugated pipe. 
         [0019]    In order to solve the above-mentioned second technical problem, the technical solution of the invention is that: 
         [0020]    a method of the residual gas heat exchange combustion-supporting system based on a methanol-water mixture reforming hydrogen production system comprises the following steps; 
         [0021]    (1) during operation of the reformer, discharging an oxygen-deficient, water vapor-containing and high-heat residual gas from the exhaust vent, which enters the first delivery passage of the heat exchange tube from one end of the heat exchange tube; and at the same time, during operation of the air intake device, bringing the outside air introduced from the air intake device into the second delivery passage of the heat exchange tube from the other end of the heat exchange tube; 
         [0022]    (2) exchanging heat between the outside air in the second delivery passage exchanges heat and the residual gas in the first delivery passage, resulting in that the outside air is warmed to turn into a high-heat air, and enters the combustion chamber of the reformer for supporting combustion: and at the same time, the residual gas is cooled to turn into residual gas with low heat, and the water vapor in the residual gas is condensed into condensed water, both the residual gas and the condensed water being discharged from the residual gas outlet of the first delivery passage. 
         [0023]    Both of the residual gas and the condensed water discharged by the residual gas outlet of the first delivery passage enter the gas-water separator for separation, the separated residual gas is discharged to the outside world via an exhaust fan, and the separated condensed water is used as a water feedstock for operation of the reformer. 
         [0024]    The invention has the following advantages: 
         [0025]    first, the invention enables a large amount of heat energy in the residual gas discharged from the reformer to be reclaimed by providing coaxial double-layer heat exchange tubes, so that the utilization rate of the methanol-water mixture feedstock of the methanol-water mixture reforming hydrogen production system is greatly improved, which is conducive to energy conservation and emission reduction; 
         [0026]    second, the residual gas discharged from the exhaust vent of the reformer usually has a temperature of from 300 to 600° C., the residual gas exchanges heat through the heat exchange tube, and the temperature will usually be reduced below 50° C., such residual gas having a low temperature is difficult to have an impact on the operation of each component of the methanol-water mixture reforming hydrogen production system, thus, can avoid the high-temperature residual gas to reduce life and stability of the methanol-water mixture reforming hydrogen production system, as well as avoid serious equipment-burning problems; 
         [0027]    third, the temperature of the outside air is raised immediately after it exchanges heat with the high-temperature residual gas in, the heat exchange tube, the temperature of the outside air can usually reach as high as 200-500° C., when the high-temperature air enters the combustion chamber of the reformer, not only the high-temperature air can provide part of the heat for the reforming chamber to reduce the hydrogen combustion amount, but also, the oxygen and hydrogen in the high-temperature air can be better combusted, such that the oxygen combustion effect is extremely good; and 
         [0028]    furthermore, in a further preferred embodiment of the present invention, a gas-water separator is provided by the invention, the gas-water inlet of the gas-water separator is communicated with the residual gas outlet of the heat exchange tube, and when the oxygen-deficient, water vapor-containing and high-heat residual gas exchanges heat through the heat exchange tube, the majority of water vapor is condensed into condensed water upon cooling, after this part of the condensed water is separated by the gas-water separator and is outflowed through the gas-water separator, which makes the water feedstock needed by the reaction for hydrogen production from methanol-water mixture reforming or for other purposes; in some areas where the water resources are in shortage and the methanol-water mixture reforming hydrogen production system is needed, such as alpine communication base stations, hydrogen stations and the like where the preparation of water is particularly significant. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0029]      FIG. 1  is a block schematic diagram showing the overall structure of the present invention. 
           [0030]      FIG. 2  is a longitudinal cross-sectional view showing the structure sketch of principal design of a preferred embodiment of the present invention. 
           [0031]      FIG. 3  is a longitudinal cross-sectional view showing the structure sketch of principal design of another preferred embodiment of the present invention. 
           [0032]      FIG. 4  is a schematic cross-sectional structure view of a heat exchange tube. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0033]    The following are further descriptions of the invention with reference to figures and examples of their applications. 
         [0034]    As shown in  FIGS. 1, 2 and 3 , the present invention is residual gas heat exchange combustion-supporting system based on a methanol-water mixture reforming hydrogen production system. The system comprises a reformer  1 , a heat exchange tube  2  and &gt;an air intake device  3 . The reformer  1  is provided with a reforming chamber, a separating device, a combustion chamber and an exhaust vent  11 , the reforming chamber is used for producing a mixed gas of hydrogen and carbon dioxide from a reforming reaction for hydrogen production between methanol and steam, the temperature of the reforming chamber is 300-570° C., and the reforming chamber is provided with a catalyst, in the reforming chamber, the methanol and the steam are subjected to methanol cracking reaction and carbon monoxide conversion reaction in the reforming chamber at a temperature of 50-570° C. and pressure of 1-5 MPa in the presence of a catalyst to generate hydrogen and carbon dioxide, and the system is a multi-component and multi-reaction gas-solid catalytic reaction system, the reaction equations are as follows: (1) CH3OH→CO+2H2, (2) H2O+CO→CO2+H2, (3) CH3OH+H2O→CO2+3H2, the H2 and CO2 produced from the reforming reaction; the separating device is used for separating the produced hydrogen. The separating device is preferably a membrane separating device which is a membrane separating device prepared by vacuum-plating palladium-silver alloy on the surface of the porous ceramics, the coating layer is a palladium-silver alloy, palladium accounts for 75%-78% of the mass percent of the palladium-silver alloys, and silver accounts for 22%-25% of the palladium-silver alloys, and the temperature in the separating device is the same as or close to that in the reforming chamber; the combustion chamber is used for the combustion of the partially prepared hydrogen and the oxygen in the outside air to provide heat for the operation of the reformer; the carbon dioxide separated out by the separating device, the water vapor generated by combustion of the hydrogen and the oxygen in the combustion chamber and the unburned gas in the outside air are mixed into residual gas which is discharged from the exhaust vent  11  to the first delivery passage of the heat exchange tube  2 ; 
         [0035]    the heat exchange tube  2 , having coaxial double-layer first and second delivery passage, and the first delivery passage is communicated with the exhaust vent  11  at one end of the heat exchange tube  2 , while the second delivery passage is communicated with the air inlet  12  of the combustion chamber of the reformer; at the other end of the heat exchange tube  2 , the first delivery passage is provided with residual gas outlet, and the second delivery passage is connected with, the air intake device  3 ; the outside air input by the air intake device  3  in the second delivery passage exchanges heat with the residual gas in the first delivery passage, the outside air with a raised temperature enters the combustion chamber of the reformer for supporting combustion, and the residual gas with a lowered temperature is discharged from the residual gas outlet of the first delivery passage. 
         [0036]    One should also note that, with reference to  FIG. 4 , the present invention adopts the names of the first transport delivery passage and the second delivery passage, and does not use to restrict the name of the outer-layer passage  11  and the inner-layer passage  12  of the heat exchange tube, but is used for distinguishing the outer-layer passage  11  and the inner-layer passage  12  of the heat exchange tube. In  FIG. 2 , the first delivery passage refers to the outer-layer passage  11  of the heat exchange tube, while the second delivery passage refers to the inner-layer passage  12  of the heat exchange tube; in  FIG. 3 , the first delivery passage refers to the inner-layer passage  12  of the heat exchange tube, while the second delivery passage refers to the outer-layer passage  11  of the heat exchange tube. As can be seen from the introduction, when the residual gas is delivered by the outer-layer passage  11  of the heat exchange tube, while the outside air is delivered by the inner-layer passage  12  of the heat exchange tube; when the residual gas is delivered by the inner-layer passage  12  of the heat exchange tube, while the outside air is delivered by the outer-layer passage  11  of the heat exchange tube. 
         [0037]    As shown in  FIGS. 1, 2 and 3 , the residual gas heat exchange combustion-supporting system based on a methanol-water mixture reforming hydrogen production system is further provided with a gas-water separator  4  which comprises a gas-water separator body  41 , and a gas-water inlet  42 , an air outlet  43  and a water outlet  44  provided on the gas-water separator body, wherein the gas-water inlet  42  is communicated with the residual gas outlet of the first delivery passage, and the air outlet  43  is connected with the exhaust fan  5 . 
         [0038]    As shown in  FIGS. 1, 2 and 3 , the water outlet  44  of the water-gas separator  4  is connected with a water purifier  6  in which an RO-membrane water purifying device is provided, and the water purified by the water purifier  6  is output to the water purification tank  7 . 
         [0039]    As shown in  FIG. 1 , the residual gas heat exchange combustion-supporting system based on a methanol-water mixture reforming hydrogen production system further comprises a methanol-water mixture storage and delivery device  8  including a methanol-water mixture storage vessel and a delivery pump, the methanol-water mixture storage vessel is stored with liquid methanol and water feedstock, and the delivery pump is used for delivering the methanol and water feedstock stored in the methanol-water mixture storage vessel to the reformer  1 ; the water output by the gas-water separator  4  or the water output by the water purification tank  7  is supplied to the methanol-water mixture storage vessel as a water feedstock, and the remaining water can be used for other purposes. 
         [0040]    As shown in  FIG. 1 , a heat exchanger  9  is provided on the delivery line between the methanol-water mixture storage and delivery device  8  and the reformer  1 , a low-temperature methanol and water feedstock exchanges heat with the high-temperature hydrogen output from the reforming chamber in the heat exchanger  9 , and the methanol and water feedstock is warmed and vaporized; the hydrogen output from the gas producing end of the separating device is cooled by the heat exchanger  9 . As shown in  FIGS. 2 and 3 , the heat exchange tube  2  is wound helically around a shell of the reformer  1 , which can not only save the space volume occupied by the heat exchange tube  2 , but also can fully lengthen the heat exchange tube  2 . The upper end of the heat exchange tube  2  is one end communicating the exhaust vent  11  of the reformer with the air inlet  12  of the combustion chamber of the reformer, and the lower end of the heat exchange tube  2  is one end connecting an air intake device  3  with residual gas outlet, which is conducive to rapidly lowering temperature of the high-temperature residual gas upon cooling, and rapidly raising the temperature of the outside air upon heat. 
         [0041]    In the above-mentioned technical solution, the heat exchange tube is any one of a coaxial double-layer titanium alloy corrugated pipe, a coaxial double-layer magnesium alloy corrugated pipe, a coaxial double-layer aluminum corrugated pipe, a coaxial double-layer copper corrugated pipe, and a coaxial double-layer stainless steel corrugated pipe, which has an extremely good rigidity performance. 
         [0042]    The above method of the residual gas, heat exchange combustion-supporting system based on a methanol-water mixture reforming hydrogen production system comprises the following steps: 
         [0043]    (1) during the operation of the reformer, an oxygen-deficient, water vapor-containing and high-heat residual gas is discharged from the exhaust vent, and the residual gas enters the first delivery passage of the heat exchange tube from one end of the heat exchange tube; at the same time, the air intake device is operating and the outside air from the air intake device enters the second delivery passage of the heat exchange tube from the other end of the heat exchange tube; 
         [0044]    (2) the outside air in the second delivery passage exchanges heat with the residual gas in the first delivery passage, the outside air is warmed to turn into a high-heat air, and enters the combustion chamber of the reformer for supporting combustion; at the same time, the residual gas is cooled to turn into residual gas of low heat, and the water vapor in the residual gas is condensed into condensed water which is all discharged from the residual gas outlet of the first delivery passage. 
         [0045]    Further, the residual gas and the condensed water discharged by the residual gas outlet of the first delivery passage both enter the gas-water separator, the residual gas is discharged to the outside world via an exhaust fan, and the condensed water is used as a water feedstock for operation of the reformer. 
         [0046]    The above-described embodiments of, the invention are only the preferred embodiments of the present invention, which may be modified or varied within the scope of the claims and their equivalents, and the invention may be practiced otherwise than as specifically described.