Gasification method

The Lurgi process has been the most commercially accepted gasification method since its commercialization in 1936, and is used in the large plants in South Africa, in modified designs in Germany, and in the United States for the Great Plains faciUty (25,49,50). 

Pyrolysis is a type of gasification that breaks down the biomass in oxygen deficient environments, at temperatures of up to 400°F. This process is used to produce charcoal. Since the temperature is lower than other gasification methods, the end products are different. The slow heating produces almost equal proportions of gas, liquid and charcoal, but the output mix can be adjusted by changing the input, the temperature, and the time in the reactor. The main gases produced are hydrogen and carbon... 

Sewage in vast quantities of billions of gallons per day could be recycled to produce a renewable source of hydrogen. This can be accomplished either by utilizing the non-photosynthetic bacteria that live in the digestive tracts and wastes of humans and other animals, or by pyrolysis-gasification methods. 

Commercial gasifiers are available in a range of sizes and types, and run on a variety of fuels, including wood, charcoal, coconut shells and rice husks. Power output is determined by the economic supply of biomass, which is limited to 80 MW in most regions. The producer gas is affected by various gasification processes from various biomass feedstocks. Table 6.7 shows composition of gaseous products from various biomass fuels by different gasification methods. 

Table 6.7 Composition of gaseous products from various biomass fuels by different gasification methods (% by volume)...

The gasification method consists of mixing coal with a mixture of two parts of the Eschka mixture (i.e., 67% w/w light calcined magnesium oxide and 33% w/w anhydrous sodium carbonate), six parts of soda lime, and one part of molybdenum oxide. The sample is then placed in a porcelain boat, covered with platinum gauze, and heated (in a quartz tube) to 200 to 250°C (392 to 482°F). The sample is then heated in steam at 850 to 950°C (1562 to 1742°F). The gases pass into 0.1 N sulfuric acid, where ammonia is chemically absorbed as ammonium sulfate and then determined by one of the usual techniques. 

V. Commercial and Near-Commercial Biomass Gasification Methods... 

V. COMMERCIAL AND NEAR-COMMERCIAL BIOMASS GASIFICATION METHODS... 

The composition of the syngas generated through different gasification methods can be totally different. Also, the gas products depend on the coal used, the oxygen purity, and the gasification conditions (e.g., temperature, pressure, reactants, and coal/oxygen ratio). Compositions of some typical coal gas products from different processes are listed in Tables 4.1 and 4.2. 

The incineration process can be subdivided into the partial processes drying, outgassing, gasification, and complete oxidation G ig. 4) [17]. These idealized processes may overlap both spatially and in time and influence each other. Pyrolytic and gasification methods involve adjustment of the framework conditions so as to favor selected processes. 

Gasification method Total energy consumption / (CJ/tNHs) Investment cost/million U.S. dollar Comparative ratio for investment... 

The varied recycling technologies of PSW have contributed greatly to the eco-image of waste management and particularly to PSW recycling, treatment and recovery. Tertiary treatment of waste plastic is by far a more sustainable solution. Advanced thermochemical treatment (pyrolysis and gasification) methods have also proven... 

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