Papers by Veli Gökhan DEMİR
Biomass has a significant proportion among all of the renewable energy sources. Bio-pellets produ... more Biomass has a significant proportion among all of the renewable energy sources. Bio-pellets produced by pelletization of bulky biomass materials are widely favoured for combustion applications because of the improvements over biomass (sawdust, agricultural residues etc.) resulting in enable to utilize and store the biofuels. In recent researches it is stated that using crude glycerol (by-product of biodiesel production) can increase the calorific value of pellets and minimize the disposal problem of crude glycerol in biodiesel industry. In this study, the crude glycerol produced from the transesterification of sunflower oil was blended in different ratios (wt %) with the sawdust of Scots pine which is commonly used in Eurasian region. Moreover, maize starch was used to examine its additive effect in drop tests. According to the optimization study, 150 MPa pelletizing pressure with 7.5% glycerol- 92.5% sawdust ratios gave the optimum results and maize starch almost didn't improve the strength of pellets. It was measured that 7.5% glycerol pellets had 89.94% drop test resistance, 89.55% volatility, 10.06% moisture content and 0.75% ash content while pure sawdust pellet had 95.54% drop test resistance, 89.63% volatility, 10.03% moisture content and 0.43% ash content. Also, 7.5% glycerol addition to the sawdust as a raw material did not affect the net calorific value of the bio-pellets (≈0.97%). As a result, it is expected that using crude glycerol directly in bio-pellet production contributes solving the disposal problem of biodiesel by-product and decreases the cost of biodiesel production.
In recent years, the concerns about fossil fuel reserves and global warming by greenhouse gases i... more In recent years, the concerns about fossil fuel reserves and global warming by greenhouse gases increase the interests on renewable energy and alternative fuels. Pellets and briquettes, one of the most used biomass form as biofuel, are generally obtained from compressed biological wastes such as saw dust, municipal solid waste, agricultural wastes in lower costs compared to charcoal, firewood, gas, coal etc. conventional fuels to be used in domestic and industrial fields. In an average olive oil production, 35wt% of olive is formed to olive cake as a waste product in continuous-process oil mills (two or three phases). In this work, the studies about production methods, fuel properties and characteristics, and utilization areas of olive cake pellets and briquettes are reviewed. Besides, in respect to the data obtained from Turkish Statistical Institute (2005-15), the annual production of olive, olive oil and olive cake for Turkey was examined. It is observed that in Turkey, a major olive producer in Mediterranean region, annually an average of 378962.5 tons of olive cake can be extracted from 1082750 tons of olive; therefore, a huge energy source exists to able to produce olive cake pellets and briquettes as a biofuel that can result in reduction of dependency on imported energy.
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Papers by Veli Gökhan DEMİR