Gas reforming process

Recently, the exhaust gas reforming process has been investigated extensively at the University of Birmingham, UK. Initial studies of exhaust gas reforming were conducted to power gasoline engines,however, the catalyst was not identified presumably it was a Ni-based SR catalyst, since very low space... 

Interaction of methane with steam on a nickel surface is the basis of the natural gas reforming process. The process is used as a source of hydrogen for ammonia production and methanol synthesis and, therefore, finds a large-scale industrial application. 

Established Methods Electrolysis. Apart from the natural gas reforming processes, electrolysis of water is the most widely used method for hydrogen production. To electrolyse water, the minimum electrical energy required is determined by the free energy change of the underlying reaction ... 

Fig. 13.1 Hydrogen in the energy system of the futine [1]. Pie-c

Wu, Jeremy. R, Brown, Ian W.M., Bowden, Mark E. Kemmitt, Timothy (2010b). Palladium coated porous anodic alumina membranes for gas reforming processes. Solid State Sciences Vol 12 ppl912-1916. 

Dalle Nogare D., Baggio R, Thomas C., Mutri L. and Canu R, (2007), A thermodynamic analysis of natural gas reforming processes for fuel cell application , Chem. Eng. Set, 62,5418-5424. 

Natural gas is by far the preferred source of hydrogen. It has been cheap, and its use is more energy efficient than that of other hydrocarbons. The reforming process that is used to produce hydrogen from natural gas is highly developed, environmental controls are simple, and the capital investment is lower than that for any other method. Comparisons of the total energy consumption (fuel and synthesis gas), based on advanced technologies, have been discussed elsewhere (102). 

Mixtures of CO—H2 produced from hydrocarbons, as shown in the first two of these reactions, ate called synthesis gas. Synthesis gas is a commercial intermediate from which a wide variety of chemicals are produced. A principal, and frequendy the only source of hydrogen used in refineries is a by-product of the catalytic reforming process for making octane-contributing components for gasoline (see Gasoline and OTHER MOTOR fuels), eg. 

Na.tura.1 Ga.s Reforma.tion. In the United States, most hydrogen is presently produced by natural gas reformation or methane—steam reforming. In this process, methane mixed with steam is typically passed over a nickel oxide catalyst at an elevated temperature. The reforming reaction is... 

These gases are then fed to the water gas converter as in the steam-reforming process, after which they are compressed to ca 20.3 MPa (ca 200 atm) for processing in the catalytic ammonia converter. 

Steam Reforming Processes. In the steam reforming process, light hydrocarbon feedstocks (qv), such as natural gas, Hquefied petroleum gas, and naphtha, or in some cases heavier distillate oils are purified of sulfur compounds (see Sulfurremoval and recovery). These then react with steam in the presence of a nickel-containing catalyst to produce a mixture of hydrogen, methane, and carbon oxides. Essentially total decomposition of compounds containing more than one carbon atom per molecule is obtained (see Ammonia Hydrogen Petroleum). 

The catalyst is then transferred back to the first process reactor and is reheated to the reforming process temperature at the reactor inlet using a flow of hydrogen-rich process recycle gas, thereby achieving reduction of the platinum to a catalyticaUy active state. 

Natural gas and crude oils are the main sources for hydrocarbon intermediates or secondary raw materials for the production of petrochemicals. From natural gas, ethane and LPG are recovered for use as intermediates in the production of olefins and diolefms. Important chemicals such as methanol and ammonia are also based on methane via synthesis gas. On the other hand, refinery gases from different crude oil processing schemes are important sources for olefins and LPG. Crude oil distillates and residues are precursors for olefins and aromatics via cracking and reforming processes. This chapter reviews the properties of the different hydrocarbon intermediates—paraffins, olefins, diolefms, and aromatics. Petroleum fractions and residues as mixtures of different hydrocarbon classes and hydrocarbon derivatives are discussed separately at the end of the chapter. 

In gas reforming plants, e.g. the hot potassium carbonate process for CO removal, sodium metavanadate is used to prevent mild-steel corrosion". Banks reports" that this treatment does not reduce the rather high corrosion rate of Cu-30Ni in these plants. 

Raw materials for obtaining benzene, which is needed for the production of alkylbenzenes, are pyrolysis gasoline, a byproduct of the ethylene production in the steam cracking process, and coke oven gas. Reforming gasoline contains only small amounts of benzene. Large amounts of benzene are further produced by hydrodealkylation of toluene, a surplus product in industry. 

Natural gas consists mainly of methane together with some higher hydrocarbons (Tab. 8.1). Sulfur, if present, must be removed to a level of about 0.2 ppm prior to the steam reforming process as it poisons the catalyst. This is typically done by cata-lytically converting the sulfur present as thiols, thiophenes or COS into H2S, which is then adsorbed stochiometrically by ZnO, at 400 °C, upstream of the reactor. 

Discuss the importance of the steam-reforming process for the production of hydrogen and synthesis gas. Is this process endothermic or exothermic What is the rate-limiting step for the steam reforming of methane ... 

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