Results from the comparative analysis of the energy and economic efficiencies of the torrefaction reactors (or low-temperature pyrolysis reactors) with the heat of the heating gas supplied directly to the processed biomass are presented. Upright reactors of two types are considered, viz., reactors with a bed of dense biomass moving by gravity towards the heating gas flow and fluidized-bed reactors. Advantages and drawbacks of the different types of torrefaction reactors are discussed. Criteria for the evaluation of the torrefaction reactors' energy efficiency have been defined based on the data of experimental research conducted on a pilot power-engineering plant at the Joint Institute for High Temperatures, Russian Academy of Sciences, equipped with a moving-bed reactor and the results of numerical modeling of a fluidized-bed reactor. The conditions for creating the thermal effect of the hemicellulose decomposition reaction and the mechanism that restricts the increase in the biomass temperature during the self-heating by the exothermic reaction heat are considered. The analysis performed has shown that a moving-bed reactor with a controlled exothermic biomass destruction reaction has the highest energy efficiency and the best criteria for estimating the financial and commercial efficiency of the investments. Conclusions have been made that moving-bed reactors are preferable for small-scale production for which granulated biomass (biomass pellets) is the optimal feedstock, while fluidized-bed reactors and fine-dispersed feedstock materials are more suitable for large-scale production.

The current state of the market of conventional and torrefied wood pellets and the trends of its development have been analyzed. The advantages and disadvantages of pellets of both types have been compared with other alternative fuels. The consumer segment in which wood pellets are the most competitive has been determined. The original torrefaction technology using exhaust gas heat from a standard gas engine that was developed at the Joint Institute for High Technologies and the scheme of an experimental unit for the elaboration of the technology have been presented. The scheme of the combined operation of a torrefaction unit and a standard hot water boiler, which makes it possible to utilize the heat of exhaust steam-and-gas products of torrefaction with the simultaneous prevention of emissions of harmful substances into the environment, has been proposed. The required correlation between the capacity of the torrefaction unit and the heating boiler house has been estimated for optimal operation under the conditions of the isolated urban village in a region that is distant from the areas of extraction of traditional fuels and, at the same time, has quite sufficient resources of raw materials for the production of wood pellets.

The production of synthesis gas by the two-stage thermal conversion of agricultural waste of plant origin (straw and sugarcane bagasse) was studied. It was

The transformations of hemicelluloses, cellulose, and lignin isolated from peat and sawdust were studied under conditions of hydrothermal carbonization and

The power industry, primarily its branch based on fossil fuel resources, is the major source of anthropogenic carbon dioxide emissions into the atmosphere of the planet. Based on direct...

The pyrolysis of coffee husks and coffee parchment at 350 and 500°C was considered as the first stage of gasification by the two-stage thermal convers