Waste to Energy plants

J. Barton, Evaluation of Trommels for Waste to Energy Plants, Phase I, National Center for Resource Recovery, Washington, D.C., 1982. 

Refuse-Derived Fuel. Many processing faciUties divert a portion of the material that is not recovered for recycling to waste-to-energy plants, also referred to as resource recovery faciUties, where the material is employed as fuel. The processes involved in the production of refuse-derived fuel (RDF) are outlined in Figure 4 (23). Nine different RDFs have been defined, as Hsted in Table 3 (24). There are several ways to prepare RDF-3, which is perhaps the most popular form and is the feed used in the preparation of densified refuse-derived fuel (d-RDF). AH forms of RDF are part of the broader set of waste-derived fuels (WDF), which includes various waste biomass, eg, from silvaculture or agriculture (see Fuels frombiomass Fuels fromwaste). 

The types of incinerators used are listed in Table 3. Municipal solid-waste furnace designs have evolved over the years, with the newer waste incinerators being waste-to-energy plants that produce steam for electric power generation. 

Camera approach Observe material, such as trash in waste-to-energy plants, as it moves through burn zone on traveling grates or stoker. Camera can detect overheat situations close to boiler tube walls. 

The composition of the exhaust depends on the type and composition of the fuel and on combustion conditions. The main components are O2 (0-15%), CO2 (3-12%), H2O (6-18%) and N2. Typical ranges of air pollutants from the combustion of natural gas, oil and coal are shown in Table I. In addition to NOx, commonly encountered pollutants include carbon monoxide (CO), hydrocarbons or Volatile Organic Compounds (VOCs), sulfur oxides (SOx) and particulates. Municipal Solid Waste (MSW) incinerator or waste-to-energy plant exhausts may also contain acid gases (e.g., HCl, HF), dioxins, furans and trace amounts of toxic metals such as mercury, cadmium and lead. 

A waste-to-energy plant, operating at over 400,000 t/year, is often capable of generating over 500 kW/h of electrical power for every tonne of municipal solid waste. If all Europe s waste were handled this way, it is estimated that 3-i% of domestic electric power could be generated from waste (Table 3.29). 

Harrop, D.O., Pollard, S.J.T. 1998. Risk assessment and waste-to-energy plants (incineration). Quantitative risk assessment for incineration is it appropriate for the UK JCIWEM 12(1) 48 53. 

Additional studies have examined the co-combustion of automotive shredder residue [47, 48, 111], electrical and electronic plastics [141-144], and building insulation foam [144] with municipal solid waste. Co-combustion of these plastics for energy production can also be carried out in compliance with U.S. and German waste-to-energy plant regulations in modem municipal solid waste combustors. 

Mayer-Schwinning G, Herden H. Use of CFB technology for cleaning off-gases from waste-to-energy plants. In Werther J, ed. Circulating Fluidized Bed Technology VI. Frankfurt DECHEMA, 1999, pp 633 37. 

In addition, cases were studied to examine the relative economic attractiveness of (i) waste-to-energy plants, (ii) conventional recycling of thermoplastics and thermosets, polypropylene in one case and nylon in another, and (iii) recycling of a thermoset plastic. 

With Flue Gas Recirculation (FGR), flue gas is introduced with the combustion air and acts as a thermal diluent to reduce the combustion temperature. Usually, the amount of flue gas recirculated corresponds to 10-20% of the combustion air. FGR reduces only thermal NO (. It is suitable only for oil- and gas-fired boilers. Results with coal have been generally disappointing. In coal-fired stoker units, FGR provides better grate cooling. FGR has been successfully applied on industrial solid fuel-flred units and is considered appropriate for waste-to-energy plants. Retrofit modifications include new ductwork, gas recirculation fan(s), flue gas/air mixing devices and controls (Makansi, 1988 Wood, 1994). Gas recirculation fans can be troublesome. 

A very high level of potassium vapor in a waste to energy plant caused the brick lining to expand and fracture due to the formation of kaliophilite from the reaction of the glassy matrix with the vapor. The kaliophilite/matrix reaction resulted in a large volumetric expansion and distortion of the brick. The problem was solved when the mullite-bonded brick was replaced with a phosphate-bonded brick. 

Air pollution control equipment in modem waste-to-energy plants accounts for around 15 to 20% of the total capital cost. Total cleaning and recycling is a process where the flue gas passes from the incineration grate to the heat recovery boiler and... 

This chapter describes the major developments in corrosion-resistant materials and coating technologies and their application in the last 30 years in waste-to-energy plants, the corrosion mechanisms of alloys, the deterioration mechanisms of spray coating layers, and future prospects for the development of corrosion-resistant materials and coatings. 

Recent trends in waste-to-energy plants and materials... 

Y. Kawahara, Recent Trends and Future Subjects on High-Temperature Corrosion-Prevention Technologies in High-Efficiency Waste-to-Energy Plants, Corros. Eng., 2005, 54, pp 213-235... 

Y. Kawahara, M. Nakamura, H. Tsuboi, and K. Yukawa, Evaluation of New Corrosion Resistant Superheater Tubings in High Efficiency Waste-to-Energy Plants, Corrosion, 1998, 54(7), p 576... 

Y. Kawahara, Y. Nakagawa, T. Hosoda, and T. Mizuko, Demonstration Test of New Corrosion-Resistance Superheater Tubing in a High-Efficiency Waste-to-Energy Plant, Corrosion/2000, Paper No. 265, Houston, TX, NACE, 2000... 

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