Gasification solid waste

This paper discusses in depth advanced technologies for recycled materials from solid waste streams. Chemical depolymerisation, thermal depolymerisation, pyrolytic liquefaction, pyrolytic gasification, partial oxidation, and feedstock compatibility are all explained. The economic feasibility of the methods are considered. 

Rogers, R. Ill (1994). Hydrogen Production by Gasification of Municipal Solid Waste. Lawrence Livermore National Laboratory (UCRL-ID-117603). 

The Texaco gasification process (TGP) is a patented ex situ commercial technology for the treatment of hazardous and nonhazardous liquid or solid waste. The high-temperature, high-pressure. 

DEVELOPMENT OF ECOLOGICALLY FRIENDLY TECHNOLOGY FOR GASIFICATION OF MUNICIPAL SOLID WASTES... 

Municipal solid wastes (MSW) gasification unit which is under development in the project consists of two fluid bed reactors (Figure 2). The first reactor is a gasifier, the second reactor is a combustion chamber for charcoal. To obtain producer gas of middle calorific value water steam is applied as a blowing. Fluid bed is organized by supplying water steam to gasifier (inert material is sand) and air to combustion chamber. The installation is equipped with all necessary devices to measure rate, temperature, and pressure. 

Pyrolysis or gasification, as processes, are both much easier to control than direct firing of plastics. The latter is impossible on mechanical grates, eqnipping conventional incinerators for mnnicipal solid waste (MSW). On the other hand, thermal conversion is feasible by means of flnidized bed technology. The few percent of plastics, as in traditional MSW is nnproblematic and the calorific content is converted into heat and often into power, albeit at a disappointing level of conversion efficiency, of the order of 15-25%. 

For fuels with a high content of volatile matter, the gas combustion downstream of the bed is crucial for emission control. The fuel bed is the Drst stage in the combustion process and generates the conditions for the latter part. A review of available literature on the experimental simulation of solid fuels confirms that the knowledge of coal combustion is more detailed than that of biomass and municipal solid waste. The knowledge of biomass gasification devices today is extensive however, sec for example La... 

Although under certain experimental condition, step 2 or step 3 may be ignored due to its non-conspicuous influence to the flnal pyrolysis product distribution, however, a good mathematical model for biomass pyrolysis should be versatile applicable to other pyrolysis conditions, and thus it should be involved the above-mentioned three steps of process, of course heat and mass transfer equations should be included also. This paper presents this kind of mathematical model. Although the model is constructed based on sawdust pyrolysis, it is quite straightforward to apply the same approach to other cases such as straw and municipal solid waste pyrolysis even if to biomass or coal gasification or metal ore reduction. 

Waste materials are too varied to be discussed in any detail here. A variety of gasification processes have been applied successfully to municipal and other solids wastes. 

Although resource recovery and recycling are receiving considerable attention today, most solid waste is still disposed of in a sanitary landfill. Even though it is widely recognized that placing solid wastes in a landfill is a misuse of potentially valuable resources, this practice will continue until economic and environmentally acceptable alternatives are found. One such alternative, the gasification of the paper fraction of solid waste is considered in this report. 

Figure 1. Solid waste gasification system for small communities...

Gasification is an energy efficient technique for reducing the volume of solid waste and the recovery of energy. Essentially, the process involves partial combustion of a carbonaceous fuel to generate a combustible fuel gas rich in carbon monoxide and hydrogen. The reader is referred to reference (6) for an excellent review of gasification reactions. 

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