Combustion of torrefined hazelnut shell with afşin elbistan lignite

The use of lignocellulosic biomass is closely related to renewable energy sources. However, natural properties such as high moisture content, low density, high volume and heterogeneous composition make lignocellulosic biomass unsuitable for bulk transportation, storage and conversion. The pretreatment applied to biomass increases the conversion efficiency of lignocellulosic biomass to biofuels, while also removing some of the natural properties of biomass that limit its use. Torrefaction is the thermal pretreatment applied to biomass for solid fuel production. Bu işlemle biyokütleden elde edilen katı ürün, birlikte yakma, gazlaştırma ve metalurjide kullanılabilir. In this study, it was aimed to convert hazelnut shell, which is an important agricultural waste in Turkey, into a usable fuel by torrefaction process and then burn it together with lignite. Therefore, hazelnut shells were subjected to torrefaction process in the fixed bed system at three different temperatures and different times as mild, moderate and severe. Torrefaction process was carried out at 200, 240, 280 °C and processing times of 0, 10, 20, 30, 40 minutes. The effects of temperature and processing time on product yield and solid product properties were investigated. To determine the properties of the solid product obtained at the end of the process and to compare it with the raw biomass; proximate, elemental, TGA and DTG analyzes were performed. The solid product obtained after the torrefaction process of the hazelnut shell at different temperatures and times was then subjected to the combustion process with Afşin Elbistan lignite. Blends containing 10%, 20%, 30%, 40% and 50% raw and torified hazelnut shells were work up into pellets with lignite. The combustion behavior of these pellets was investigated at 550-700 oC different furnace initial temperatures in the fixed combustion system. Combustion behavior of raw lignite, raw hazelnut shells and torified hazelnut shells and blends were determined by ignition time, volatile matter combustion time, carbon combustion time, volatile matter combustion rate and carbon combustion rate. It was observed that the torrefaction solid product yield decreased and the process temperature was more effective than the process time. It was observed that there was an increase in the carbon content and calorific value of the torrefied solids, and when the TGA and DTG curves were examined, the lignin content was high in the solid product obtained in severe torrefaction. It was determined that the fuel type, volatile component and moisture in the fuel were effective on the ignition time at combustion temperatures where the furnace initial temperature is low. It was concluded that there was no relationship between the volatile matter combustion time and the volatile matter combustion rate, but there was a relationship between the carbon combustion time and the carbon combustion rate. It was observed that the sample obtained from severe torrefaction during the volatile matter and carbon combustion period affected each other during combustion with lignite and behaved like a different fuel.