Gas: heating and illuminating – Apparatus for converting or treating hydrocarbon gas
Reexamination Certificate
2000-03-13
2004-05-11
Johnson, Jerry D. (Department: 1764)
Gas: heating and illuminating
Apparatus for converting or treating hydrocarbon gas
C048S061000, C048S06200R, C048S063000, C048S089000, C048S094000, C048S095000, C048S119000, C048S198100, C048S198300, C048S198700, C048S211000, C048S212000, C048S21400A, C048S215000, C422S186220, C422S186220, C422S198000, C422S198000, C422S211000, C422S217000, C422S222000
Reexamination Certificate
active
06733552
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a hydrogen generating, apparatus which uses a fuel hydrocarbon or the like and water as raw materials and gives a hydrogen gas by steam reforming of the fuel.
For producing hydrogen, there are methods of steam reforming of fuels. In these methods, fuels such as natural gas, hydrocarbons like LPG, alcohols like methanol, naphtha and the like and water are used as raw materials and the fuels are subjected to a steam reforming reaction in a reforming part or reactor equipped with a reforming catalyst to generate hydrogen. There is also provided a shifting part conventionally for shifting water and carbon monoxide since carbon monoxide is produced as a by-product in the above-described steam reforming reaction.
Further, when a steam reforming method is used for supplying hydrogen to fuel cells, particularly to a solid polymer fuel cell, a purification part utilizing a carbon monoxide oxidizing method, methanization method or the like is provided for further removal of carbon monoxide in a shifted gas passed through a shifting part. The above-described reforming part, shifting part and purification part are equipped with catalysts corresponding to respective reactions and the reaction temperatures differ depending on the catalysts, therefore, there is a need to heat respective catalysts to respective reaction temperatures for stable generation of hydrogen.
In such hydrogen generating apparatuses, the temperature in the reforming part is most high and the temperature lowers gradually in the order of the reforming part, the shifting part into which a reformed gas flows in and the purification part into which a shifted gas flow in since a heating part is provided only in the reforming part situated at the upstream side. Therefore, there has been adopted a constitution in which the shifting part and the purification part are heated sequentially with heat from the reforming part, for example, heat kept in reformed gas or surplus heat in the heating part.
In such constitution, however, a long time is required before the catalyst temperatures of respective reaction parts (reforming part, shifting part and purification part) are stabilized. Surely, there is no specific problem in a hydrogen generating apparatus which is usually operated in continuous mode used in a plant and the like since the operation can be effected while estimating the starting-up time. However, such constitution is not preferable in a hydrogen generating apparatus which effects frequent starting up and stopping and needs stable generation of hydrogen in a short period of time.
On the other hand, there is also used a method in which special heating parts are provided to respective reforming part and purification part and the starting-up time is shortened by allowing the heating parts to actuate when catalysts are heated in starting up the apparatus. This method, however, has a problem that constitution becomes complicated or the cost of the apparatus increases due to integration of the heating parts into the apparatus.
The first object of the present invention is to provide a hydrogen generating apparatus assuming daily starting-up and stopping in which the temperatures of catalysts in respective reaction parts can be stabilized in a short period of time by a simple constitution, in view of the above-described facts.
In the above-described steam reforming, hydrocarbon-based fuels such as methane, propane, gasoline, kerosene and the like are reformed at temperatures from about 500 to 800° C., and alcohol and ether-based fuels are reformed at temperatures from about 200 to 400° C.
In this reforming, higher the reaction temperature, higher the concentration of carbon monoxide (CO) generated, therefore, particularly when hydrocarbon-based fuel is used, a CO shifting catalyst is used and CO and steam are reacted to reduce the CO concentration down to 0.1 to 1% for example.
Particularly in the case of a fuel cell which works at a lower temperature of about 100° C. like a solid polymer fuel cell, there is required decrease in the CO concentration down to several ppm level, hence causing use of a CO purification catalyst which selectively oxidizes CO by addition of a trace amount of air. This catalyst has been used as a catalyst body having a form of pellet such as cylindrical, spherical and the like.
However, when a catalyst body in the form of a pellet is used, there has been a problem that since the catalyst body collapses due to heat impact in each starting Lip of a fuel cell and vibration in being mounted on vehicles and the like, the catalyst can not be used until the life inherent to the catalyst component due to generated need of exchange with a novel catalyst body. There has been also a possibility that a catalyst powder produced by collapsing of the catalyst body obstructs the fuel flow route of a fuel cell.
Namely, conventional hydrogen generating apparatuses have no large problem in uses wherein only stationary operation is conducted in chemical plants and the like and frequent starting up operation is not required, however have problems in uses wherein stopping of operation and starting up are repeated and vigorous vibration occurs such as in fuel cells for domestic use or for vehicle use.
The second object of the present invention is to provide a hydrogen generating apparatus which can allow the ability of a catalyst body to be fully manifested and can provide utilization of the full life of the catalyst body, causing stable operation for a long period of time, even in uses wherein stopping of operation and starting up are repeated and vigorous vibration occurs, in view of the above-described facts.
Further, conventional hydrogen generating apparatuses which provide generation of hydrogen by the above-described steam reforming have no means provided between these reforming catalyst body, CO shifting catalyst body and CO purification catalyst body to prevent catalyst components from scattering.
When means to prevent scatter of a catalyst are not provided, there is a possibility that heat impact is applied to a catalyst body in starting up the hydrogen generating apparatus, a catalyst body collapses due to vibration when placed on vehicles, and when used for a long period of time, fallen catalyst components fly to the downstream side of a catalyst body.
In this case, the scattered reforming catalyst methanizes a reformed gas, the scattered CO shifting catalyst prevents selective oxidation of CO and increases the CO concentration by a reverse shift reaction, providing a factor causing reduction in efficiency of the whole apparatus.
Thus, conventional methods have no large problem in uses wherein only stationary operation is conducted in chemical plants and the like and frequent starting up operation is not required, however have a lot of problems in uses wherein stopping of operation and starting up are repeated and vigorous vibration occurs such as in fuel cells for domestic use or for vehicle use.
The third object of the present invention is to provide a hydrogen generating apparatus which eliminates influence by scatter of a catalyst body and operates in a stable manner for a long period of time, for solving the above-described problems of hydrogen generating apparatuses, in view of the above-described facts.
BRIEF SUMMARY OF THE INVENTION
The present invention provides, for first attaining the above-described first object, a hydrogen generating apparatus comprising a fuel feeding part, a water feeding part for fuel reforming, an oxidant gas feeding part, a reforming catalyst body, a heating part for the above-described reforming catalyst, a CO shifting catalyst body and a CO purification catalyst body and in which the reforming catalyst body, the CO shifting catalyst body, the CO purification catalyst body being placed sequentially in this order form the above-described fuel feeding part toward the downstream side, wherein a fuel and water are fed to the above-described reforming part which has been heated, an oxidant gas from the above-described oxid
Kitagawa Kouichiro
Shono Toshiyuki
Taguchi Kiyoshi
Tomizawa Takeshi
Ukai Kunihiro
Akin Gump Strauss Hauer & Feld & LLP
Johnson Jerry D.
Matsushita Electric - Industrial Co., Ltd.
Ridley Basia
LandOfFree
Hydrogen generating apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Hydrogen generating apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hydrogen generating apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3191904