These torrefied briquettes were more durable (94% DU) than raw briquettes (85% DU) directly following production, but were less durable after undergoing temperature and humidity fluctuations associated with long distance transportation (74% DU for torrefied and 84% DU for raw biomass briquettes). Their specific grinding energy was an average 37% of the energy required to grind a raw biomass briquette. Torrefied briquettes produced at these conditions had a neatly stacked packing density of 990 kg m -3and a volumetric energy density of 21,800 MJ m -3. These conditions were able to process 510 to 680 kg h -1(wet basis) feedstock with a dry mass yield of 79% to 84% to produce torrefied biomass with a higher heating value of 21.2 to 23.0 MJ kg -1(dry basis) compared to 19.6 MJ kg -1for the original biomass. Optimal operating conditions, evaluated based on throughput rate, specific electricity demand, torrefied briquette grindability, briquette volumetric energy density, and briquette durability, were identified to occur with a short residence time (10 min), low feedstock moisture content more » (<11% wet basis), and high final product temperature between 267☌ and 275☌. Experiments were conducted at various conditions with feedstock moisture content ranging from 4% to 25% (wet basis), reactor residence times of 10 and 20 min, and final product temperatures between 214☌ and 324☌. A semi-mobile torrefaction and densification pilot plant was constructed in order to determine ideal operating conditions and evaluate briquette quality and throughput rate using forest residuals as the input feedstock. Some scaling and corrosion does occur on the downhole heat exchangers (black iron pipe) and on heating systems where the geo-fluid is used directly. Well water chemistry indicates approximately 800 ppM dissolved solids, with sodium sulfate having the highest concentration. Larger facilities and district heating systems use lineshaft vertical turbine pumps and plate heat exchangers. = C) and the most common practice more » is to use downhole heat exchangers with city water as the circulating fluid.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |