| Abstract [eng] |
In 2011 only 1.1 % of straw fuel potential was used. In Lithuania the total and heretofore the largest amount of straws collected in 2012 was 4 mln. t. One third of this amount is recommended to be exploited for energy needs, i.e. from approximately 1.32 mln. t. of straw fuel, 441 ktoe energy can be obtained. The aim of this research is to evaluate the maximisation of energy recovery from the straw for the decreasing environmental impact. To evaluate the efficiency of straw regeneration the comparative straw fuel analysis is used. To fulfil the aim of this research the comparative analysis is used, i.e. the input of energy (MWh) required to produce 100 MWh heat energy from the incineration of straw pellets and straw rolls is evaluated. In this research three alternatives at farmer level are suggested: by natural gas, coal and diesel fuel operating boilers are replaced into straw boilers. The fourth alternative is suggested at industrial level: by natural gas operating boiler in PLLC “Pakruojo šiluma” is suggested to be replaced with straw pellet boiler. For the implementation of these alternatives the feasibility studies (technical, environmental and economic) are chosen. In order to carry out the feasibility studies the balance of energy and material was made, the concepts of cleaner production and industrial symbiosis were applied, the indicators of environmental protection were evaluated. It is identified that the pelleting of straws collected 50 km circumference from boiler plant is inefficient. In order to produce 100 MWh heat energy from straw pellets the total amount of energy needed is double in comparison to heat energy production from straw rolls. It is identified that straw fuel, according to energy regeneration ratio, corresponds the sawdust biofuel. According to the analysis, if all alternatives were applied, the environmental and economic benefit would be obtained. In case of first alternative the impact for atmosphere would decrease by 97.9 %. Electricity input required for the production of heat energy would decrease by 27.3 %. It was evaluated that suggested alternatives at the farmer level would buy off in 2 years. In case of second cleaner production alternative fuel input would decrease by 7.94 %, the impact for atmosphere would decrease by 98.9 %, the alternative would buy off in 4.6 years. In case of the third alternative the impact for atmosphere would decrease by 98.3 %. Electricity input would decrease by 42.9 % and the alternative would buy off in 1.6 years. In case of fourth alternative it was identified that due to the increase of boiler’s efficiency ratio, fuel input would decrease by 15.2 %. The impact for atmosphere would decrease by 97.9 % and the electricity input required for the production of heat energy would decrease by 38.82 %. This alternative for the company would buy off in 2.4 years. |
