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Title: Substitute Liquid Fuels Used In Cement Kilns - Life Cycle Analysis
Author: Agency; Bristol Environment
Author: Environment Agency
Document Type: Monograph
Annotation: Environment Agency Project ID:EAPRJOUT_465, Representation ID: 147, Object ID: 1804
Organic wastes are currently blended to form Substitute Liquid Fuel (SLF) for use in cement kilns. Although subject to strict regulation by the Environment Agency, there are concerns relating to the use of SLF. Chem Systems was commissioned to review the position of the SLF aroute in the environmental hierarchy using Life Cycle Assessment methodology. ..A further aspect of the study was whether SLF draws material from recycling or hazardous waste incinerators for economicreasons. Waste Arising! Wastes suitable for -blending. into SLF arise from several sources. Solvent wastes are produced by,fine chemical producers and by industries using solvent-based products, such as coatings. Process wastes .occur ,in the chemical and other process industries. One potential contributor toaSLF is waste lubricating oil, which is used-in cement.kilns in Germany but ,not the UK;:~.. Material currently being blended into SLF includes a wide range of compositions from which the SLF blend specification is compiled. Some .wastes are largely aqueous. and some have high halogen or metal contents. Life Cycle Assessment -(I,CA) In the LCA, the environmental burdens of sending one kilogram of organic .waste to different disposal routes are considered.. The SLF. option is preferable to ,hazardous waste incineration for most parameters.- This is because the SLF reptaces conventional cement kiln fuels, coal and petroleum- coke. From data available, the SLF route can result -in somewhat higher emissions of..inorganic halogen compounds ,and semi-volatile and volatile metal compounds. than :incineration, though this might depend on the total, quantity and retention is in any case high in .both disposal options. Recycling of solvents is environmentally preferable to incineration on. almost. every count. Recovery of solvent to leave a dry residue is preferable, to recovery at 60-70 .percent with incineration ..of residues. However, recycling does not necessarily show a consistent environmental advantage over sending SLF ato cement kilns. This depends on the solvent. Incinerators are designed for very-high retention of certain contaminants, such as sulphur or halogens. The retention in cement kilns, although high, amay not be as good. If the concentration- of. such .contaminants in a .unit of SLF is particularly.high, then the other advantages of the SLF route-may be outweighed.. Tentative suggestions are therefore made in the. report for contaminant. levels at which wastes should be excluded from SLF. Administration of such an. exclusion scheme would be difficult, however. R and D Technical Report P274 iv Economics The analysis of economics suggests that it is more attractive to recover solvents than to blend the total waste into SLF. However, the use of SLF as a disposal route for solvent recovery residues can confer a competitive advantage over other recyclers. This route could compete in some cases with recovery to dryness. SLF blenders are able to charge very much lower gate fees than the usual fee targets of incinerators. Chem Systems has been unable to identify evidence to demonstrate that SLF has taken feedstock from solvent recycling or, to a damaging extent, from incinerators. Quantities Estimates have been made of the quantity of organic wastes in the UK that would be candidates for SLF, and the maximum possible demand for SLF cement kilns. The potential demand for SLF is a very significant part of total arisings, and substantial in comparison with current incinerator capacity. Current indications are, however, that cement producers would not choose to use SLF to this maximum extent. Substitute Liquid Fuels, SLF, cement kilns, combustion, waste, co-incineration, hazardous waste, Life Cycle Analysis, recovery, solvent, recycling R and D Technical Report P274 V 1.
Publisher: Environment Agency
Subject Keywords: Waste; Solvent; Recycling; Combustion; Hazardous waste; Substitute liquid fuels; Slf; Cement kilns; Co-incineration; Life cycle analysis; Recovery
Extent: 109
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