Abstract. A paper presents mathematical modelling and experimental results of grain drying in a dryer with pseudofluidized bed with intermittent drying media supply, working on producer gas. A system of four differential equations that interconnects the grain moisture content and temperature and drying media temperature humidity are presented. Straw and producer gas consumption for grain drying is presented. A multifactor experiment is done, where the drying media temperature, number of sections and sections blowing time are variable factors. Response surfaces are built on these data. Experimental results let us define the optimal calm period to the blow period ratio and drying media temperature that provide the highest grain moisture evaporation tempo. The obtained measurement results are in high correlation with the calculations. It illustrates that using gasifier technologies to supply grain dryers is expedient and provides high indexes of economical, energetic and ecological effectiveness, when using straw with the moisture content range of 10-30 %. Using this dryer lowers specific expenses on after harvesting post processing up to 30 %.Keywords: fluidized bed, grain drying, gasifier technologies. IntroductionIn Ukraine existing drying modes in installations with periodical and continuous action do not provide substantial during quality and correspondent energy expenditures. The existing dryers have a low coefficient of productivity (CoP) and high specific material consumption [1].As an alternative for convectional type dryers there are dryers with pseudofluidized bed [2]. Moist product is dried in the pseudofluidized layer that is created by heated drying media provided through the distribution system maintaining a "boiling" layer in the drying chamber [3][4][5]. Herewith created mode mixes the product effectively that raises the heat transfer coefficient, raising the whole product volume drying effectiveness [4]. While grain is moving in the "boiling" layer through the dryer sections, the used drying media is evacuated through the system of filters and cyclones [2; 6; 7]. For companies that have a surplus of straw, to provide production self-sufficiency and high indexes of ecological and energy efficiency it is expedient to equip dryers with gasifiers [8; 9].Besides pros such dryers have some disadvantages. Separate grains, because of mixing, spend unequal time in the layer. As a result the grain mass can be processed unequally, that is not good especially for sowing grain. Using the gasifier as an energy supply for the dryer makes the situation even more complicated. Thus, there are sufficient achievements in the area of gasifying, especially agricultural raw material and its mixtures [10], however, there is still a problem of coordination between the thermo-technical modes of the gasifier and the dryer operation [9; 11].There are quite enough scientific investigations describing the drying process in the pseudofluidized layer [3; 5; 12], although not all of them represent modelling of drying grain materi...

To gasify low quality biofuels it is proposed to use a downdraft gasifier with productivity by gas 60-68 m 3 •h-1. The research was made for fuel mixtures of chopped straw and hydrolyzed lignin with variable acidity. A multifactor experiment was made to estimate the influence of acidity and the moisture content of fuel mixture as well as temperature in an active zone of the gasification chamber on corrosion rate of an experimental specimen made of 15Cr21N5T. Similar experiments were made for specimens made of S32109, A57036 and Ni70Cr27Al. It was found that the moisture content influences corrosion more than acidity. Minimal corrosion rate was observed for fuel mixture with the moisture content 25 % and pH6. When raising temperature in the gasification chamber active zone from 600 to 1000 ºС, the corrosion rate rises by 8 % for the mixture with the moisture content 25 % and pH6 and by 17 % for the mixture with the moisture content 45 % and pH5. Within the interval 900-1000 ºС the highest quality producer gas was received having the calorific value of 9.6 MJ•Nm-3 with output of 2.7 m 3 •kg-1. It is confirmed that between 900-1000 ºС chloride and sulphide corrosion is significant for all types of materials. Raising the nickel content in alloy is lowering its corrosion resistance, which is confirmed with the specimen made of Ni70Cr27Al. Adding superheated steam to blowing gases is intensifying all corrosion processes. The received results of the corrosion processes could form a base of studying and computing other types of thermo-chemical conversion of low quality biofuels with similar chemical composition.