The gasification rate of fuel, biomass gasification in particular, is an important parameter which is worth considering in the process of creating a gasifier with a continuous operation process. The gasification of biomass is a complex thermochemical process. The theoretical and practical studies of the gasification rate of biomass are complicated because of a high thermochemical rate of reactions in the functioning zones of a gasifier. The complexity of the study prevents the achievement of the required accuracy of the analytical model of the gasification rate of biomass. The known theoretical models of the gasification rate only partially describe the dynamics of the gasification rate of biomass. Moreover, most scientific studies are focused on establishing the effects of gasifier parameters and the gasification process on the quality indicators of the received gas but not on the gasification rate of fuel. To build an accurate model of the gasification rate the authors propose a series of experimental studies in a well-defined range of the parameters of a gasifier. The paper suggests a simple mathematical model of the gasification rate of biomass, which is proportional to the amount of plant biomass that remained non-gasified. The coefficients of the gasification rate for straw pellets, wood pellets and wood in pieces have been determined. Under a minimal air supply into an active zone of a gasifier (0.00088 m3/s) a coefficient of gasification rate is nearly the same for the test fuel materials and it differs by 4.7% between wood pellets and straw pellets. When the air supply increases, the gap between the coefficients increases as well and it reaches 9.44 × 10−5 c−1 for wood pellets, 1.05 × 10−4 c−1 for straw pellets and 8.64 × 10−5 c−1 for wood in pieces under air supply into an active zone of a gas generator of 0.01169 m3/s. Straw pellets have the highest gasification rate and wood in pieces has the lowest gasification rate.

This paper offers an algorithm to account for potential actions on the efficient production of renewable energy. The algorithm consists of a substantiated choice of a certain type of renewable energy, the evaluation of its potential, and the regulation of the processes of obtaining that renewable energy. Also, potential resources for agricultural biofuel production have been analyzed and it has been determined that there is real biomass potential in Lithuania. It will thus be beneficial to make appropriate managerial decisions on the methods of biofuel processing and consumption, as well as on means of receiving the economic, energy and environmental effects. The total potential of by-product biomass of crop production was determined, and the thermal and electric potential of the crop by-products were calculated. Additionally, the potential for production of gas-like types of fuel (biomethane, biohydrogen, and syngas) from crop by-products was determined. The potential for the production of diesel biofuel from oil crop waste (bran) was also found, and the potential for livestock by-products for receiving gas-like types of fuel (biomethane, biohydrogen) was established. The corresponding thermal and electric equivalents of the potential were found and the potential volumes of the biomethane and biohydrogen production were calculated. The total energy equivalent equals, on average, 30.017 × 106 GJ of the thermal energy and 9.224 × 106 GJ of the electric energy in Lithuania. The total potential of biomethane production (taking into account crop production and animal husbandry wastes) on average equals 285.6 × 106 m3. The total potential of biohydrogen production on average equals 251.9 × 106 m3. The cost equivalents of the energy potential of agrarian biomass have been calculated. The average cost equivalent of the thermal energy could equal EUR 8.9 billion, electric energy—EUR 15.9 billion, biomethane—EUR 3.3 billion and biohydrogen—EUR 14.1 billion. The evaluation of the agricultural biomass potential as a source of renewable energy confirmed that Lithuania has a large biomass potential and satisfies the needs for the production of renewable energy. Thus, it is possible to move to the second step, that of making a decision concerning biomass conversion.

Biohydrogen production in agricultural enterprises is an urgent matter. It is appropriate to utilize two methods of biohydrogen production: a thermochemical method – from crop-based biomass and anaerobic digestion (fermentation) method – from animal-based biomass.. It is appropriate to use gasifiers for the thermochemical method and biore-actors for fermentation method. The theoretical potential of biohydrogen was established with due regard to the amount of biomass which is necessary for utilization in livestock agriculture, for fields fertilization as well as with the consideration of the coefficients of concordance with hydrogen equivalent and loss factor under biohydrogen production. The theoretical potential of biohydrogen from crop-based biomass in Ukraine amounts to 77 billion m3, during the period of three years (on average 25.6 billion m3 per year).

In this work, a study was performed on the influence of the ratio of height to the diameter of the reduction zone of a small-size downdraft gasifier as well as of the fuel fraction sizes on the gas quality (the quality was evaluated for CO content). The ratio of a full side area to the volume of a fuel fraction (SVR) was used as a fuel parameter. The maximum CO concentration was observed when using a small fuel fraction with SVR—0.7–0.72 mm−1 and when adhering to the ratio of height to the diameter of the reduction zone H/D—0.5–0.6. The maximum electric power for gasoline generators (nominal power equaled 4 kW) when using the gas received from the fast-growing hybrid willow biomass equaled 2.4 kW. This power is 37.5% lower than when using gasoline and 7.0% lower than when using the gas received from the hardwood biomass. The emissions of harmful gases into the atmosphere by the gasoline generator engine equaled 0.12–0.14% CO and 24–27 mln−1 CxHy. The emissions were 64.8 times less for CO and 8.5 times less for CxHy when compared with using gasoline.

The analysis of scientific investigations makes it possible to make a conclusion about the usefulness of the generator gas as a fuel for internal combustion engines of mobile power generators. Under the conditions of agricultural production and in rural areas, the generator gas can be generated from biomass (wood, straw, corn stalks and other plant refuse). The paper recommends to use a gasifier of the reverse process for gas generation. The side of the recovery zone of the gasifier is 200 mm long, and the recovery zone is -70 mm high. The number of tuyere holes is 20, the diameter of the tuyere holes is 10 mm. The research was conducted in order to determine the effects of the produced generating capacity on generator gas and air consumption, as well as on emissions of greenhouse gases (CxHу and CО). The paper shows the nature of the effects of the produced generating capacity on generator gas and air consumption by the engine of a mobile power generator. As follows from the investigation, under the generating capacity, which corresponds to nominal electric generator charge, under the use of generator gas generated from wood CO emission is up to 25 times less, and CxHу emission is up to 9 times less as compared to gasoline fuel. While using the generator gas generated from straw, CO emission is up to 25 times less, and CxHу emission is up to 4 times less as compared to gasoline fuel. The paper also shows the results of the investigation as to the impact of the engine exhaust supply of a power generator engine into the combustion area of a gas generator on the power generator schedule, as well as on the dynamic pattern of the generated effective power.