Assessment of energy consumption of pellets and briquettes production in compressing devices

Abstract

Article history: Received: September 2013 Received in the revised form: November 2013 Accepted: January 2014 Assessment of energy consumption of pellets and briquettes production from plant raw materials was presented. Wheat, rye, rape straw and meadow hay were used for their production. The investigated raw materials were ground before briquetting with the use of a station drum straw cutter and theoretical length of cutting of 20 mm, whereas before pelleting – with the use of a beater grinder equipped with sieves of 6 mm meshes diameter. Analysis of moisture of raw materials and their calorific value were carried out according to binding norms. Moisture of compacted raw materials was within 10.1-13.3%, whereas the calorific value was from 16.1 to 17.9 MJkg. Pellets were produced in a pelleting machine with an immobile flat matrix and driven compressing rolls, whereas briquettes were produced in a screw briquetting machine with a heated compressing chamber. The following values of temperature of the compressing chamber of a briquetting machine were assumed: 200, 225 and 250oC. For measurement of energy consumption of the raw materials compression process power, time and electric energy converter Lumel 3000 was used. Average values of energy consumption during production of pellets were from 0.145 kWhkg for rape straw to 0.176 kW⋅kg for meadow hay. In case of production of briquettes the lowest value of energy intake was reported for wheat straw compressed in temperature 250oC (0.128 kWh⋅kg), whereas the highest value of energy intake for meadow hay compressed in temperature 200oC (0.182 kWh⋅kg).