Research of Wheat Drying in a Microwave and Combined Filter-microwave Dryer

The aim of the conducted study is to determine kinetics of the complex effect of microwave energy supply and filter drying of the process of water release from the wheat layer. There is offered a combination of MW and filter drying. A special feature of this combination must be its more effectiveness and high speed of water elimination from surface layers of wet seeds and, as a result, the productivity increase of the drying way, decrease of specific energy consumption.There was determined the influence of the specific load of the material, radiator power on processes of microwave and filter-microwave drying of wheat seeds. There were compared microwave, filter-microwave and convective drying of seeds by parameters of specific energy consumption, drying speed.The specific energy consumption at microwave drying of seeds was 4 MJ/kg, at filter-microwave drying 3.8 MJ/kg that is lower than existent convective dryers. The speed of microwave drying changes from 0,5 to 3 %/min, filter-microwave – from 0.3 to 0.7 %/min. The speed is at the level of standard convective dryers.The conducted studies allow to recommend a new combined way of FMW drying of seeds with low energy consumption.Revealed features of heating and drying are possible to be used at developing industrial dryers.The base of experimental data is possible to be used for optimizing and determining effective conditions of MW and FMW drying

Experimental Studies of the Kinetics of Infrared Drying of Spent Coffee Grounds

The object of research is drying of spent coffee grounds. In modern production, the issues of rational use of energy in all processes of food technology, including drying, are urgently raised. In many food technologies, 2–3 times more energy is used than is physically necessary for the process. This determines the energy intensity of production and the quality of products. Drying processes are among the most energy-intensive, and in many cases the proportion of energy in the cost of production is up to 30 %. When drying of spent coffee grounds, convective dryers are mainly used, the energy consumption of which is 5 MJ/kg of removed moisture and above. Convective drying uses 40 % of the supplied energy to evaporate moisture. Also, a significant drawback of convective dryers is the discharge of waste coolant into the atmosphere, which has a heat content of only 10–15 % less than the hot air supplied to the drying chamber. The paper proposes the use of infrared radiation for drying of spent coffee grounds in periodic and continuous units. This will allow in the future to reduce specific energy consumption. During the study, the influence of the energy supply intensity, temperature, air flow rate, product layer thickness and specific load on the kinetics of periodic infrared drying of spent coffee grounds is determined. The influence of the energy supply intensity, specific load, tape speed, and the number of infrared modules on the kinetics of continuous infrared drying of spent coffee grounds is determined. The results are compared with convective drying in terms of specific energy consumption. A feature of the use of infrared radiation is its high efficiency and high rate of moisture removal from the surface layers of spent coffee grounds, and as a result, an increase in the productivity of the drying method and a decrease in specific energy consumption. The specific energy consumption obtained during operation of infrared drying of spent coffee grounds is 3.2 MJ/kg. This is below existing convection dryers