Patent ID: 10041015

Abstract:
A methodology for the removal of the harmful components of the ash of biomass of agro/forest/urban origin and of low-quality coal fuels, as peat, lignite, sub-bituminous and bituminous coals, is invented. The harmful components are alkaline metals, chlorine and sulphur. They are removed before the thermochemical conversion in order to prevent or minimise the corrosion, scaling/deposition, ash agglomeration problems, as well as the alkaline metal, chlorine, sulphur emissions. Furthermore, it aims in the production of materials of low moisture content, low hygroscopicity, which can be easily ground, and mixed with various other materials, easily fed to commercial boilers for energy production, which can be easily pelletised with or without other materials at various proportions and with very low energy requirements. The removal is achieved with pre-pyrolysis/pre-gasification at 250-320° C. for 5 min to 2 h of biomass of agro/forest/urban origin, as well as, of low-quality coal fuels, as peat, lignite, sub-bituminous and bituminous coals. Then the pre-pyrolysed/pre-gasified sample is washed with a 0.5%-20% weight basis aqueous calcium acetate and/or magnesium acetate and/or aluminum acetate and/or ammonium acetate solution. These acetate salts can be mixed in a proportion of 0% to 100% to form an active salt which is used for the preparation of the aqueous solution. Any kind tap water from a public water supply system, spring, etc. can be used for the preparation of aqueous solution. The solid-to-liquid ratio is 33 g/L to 600 g/L, the temperature varies from 13° C. to 95° C., and the treatment duration between 5 min to 24 h.