GREENHOUSE GAS REDUCTION

摘要

The best and most economic method of reducing the pollution of the atmosphere by greenhouse gases is generally not to produce any such gases. This may not in most cases be a practical alternative, however, so therefore our aim has to be set to minimize the emission of those gases. The first option in the field of greenhouse gas reduction technology choices when producing e.g. energy and/or dry goods is generally to use methods requiring the lowest level of energy input in the overall process. Among production areas having high energy requirement there is one field that in particular is of importance -drying of wet materials - a unit process that is common in e.g. pulp and paper manufacturing, production of dry foods and energy production based on various kinds of biomass. The reason for the importance of finding low energy consumption in drying in various manufacturing and production processes is the very high heat of vaporisation of water. An enormous amount of energy is spent unnecessarily in drying processes around the world and a lot of this energy is wasted due to low process efficiency leading to unnecessary greenhouse gas emissions. This deficiency can be corrected in many drying applications by the use of a well balanced and efficient combination of present and new technology. By using a low amount of energy input in drying a considerable reduction in greenhouse gas emission will be obtained as well as more economic drying and less amounts of various harmful volatile compounds emitted to the atmosphere. When the dried material, e.g. biomass of even and well controlled moisture content, is then burned in steam boilers less energy is being used, less carbon dioxide emitted to the atmosphere as a result of the total energy production concept including biomasss preparation as well as the steam boiler operation. A new efficient drying process and equipment including required process control has been outlined according to the above criteria. This also fulfills the important requirement of maintaining an even and desired level of moisture content of the biomass fuel for steam boilers in order to obtain a high burning efficiency. Thereby the reduction of the carbon dioxide emissions is further enhanced.