Basic Research On The Biodiesel Production From Fatty Wastes

Research on Biodiesel has received much attention as a clean renewable energy source,but the high cost of raw materials has severely constrained its development.In this study,oleaginous yeast and primary sludge were studied.On the one hand,the lipid accumulation ability of Yarrowia lipolytica?YL?was improved by UV mutagenesis and domestication,and the selected high-yield yeast was used to treat the simulated restaurant wastewater.The mutagenized YL could utilize and reduce the oil effectively from the restaurant wastewater,which provide the possibility for producing biodiesel from the accumulated lipid of the yeast.On the other hand,the solid acid catalyst from pomelo peel as raw material was prepared to catalyze the lipid from primary sludge for biodieselproduction and the esterification conditions to reduce the cost of biodiesel production was optimized.The main conclusions are as follows:?1?Gradient acclimation of YL with a single oil-carbon source can improve the lipid accumulation ability.When the concentration of oil in the culture medium increased from 20.0g/L to 40.0g/L,the biomass concentration of YL was increased from8.34g/L to 10.34/L,the lipid yield was increased from 1.91g/L to 2.97g/L and biodiesel yield was increased from 1.35g/L to 2.08g/L.?2?The lipid accumulation ability of the YL didnot improve when glucose was added into the oil substrate,whereas the lipid accumulation in YL was increased from37.35%to 41.50%when 5%sodium acetate was added into the oil substrate.?3?The lipid accumulation ability of YL could be enhanced by ultraviolet mutagenesis.The result showed that YL13 was selected as high-yield yeast,compared with original yeast.The biomass concentration of YL13 was increased from 8.34g/L to11.90/L,the lipid yield was increased from 1.91g/L to 3.18g/L and the biodiesel yield was increased from 1.35g/L to 2.42g/L when YL13 was cultured in medium of 20.0g/Loil concentration.?4?The oil utilization rate reached 71.0%and the biodiesel yield was 2.01 g/L when YL13 was used for treating simulated restaurant wastewater with an oil concentration of 20.0 g/L.This showed that the YL mutagenized by ultraviolet radiation could utilize and reduce the oil effectively from the restaurant wastewater,which provide the possibility for producing biodiesel from the accumulated lipid of the yeast.?5?The solid acid catalyst from pomelo peel as raw material to catalyze the lipid from primary sludge was prepared to produce biodiesel.The preparation condition of optimal catalyst(HBC₄₀₀-SO₃H)was:carbonization 2h at 400?,modification 1h by10%H₂SO₄ solution at 65?,sulfonation 12h at 150?.?6?The optimum reaction conditions of the optimal catalyst were as follows:reaction temperature of 55?,reaction time of 24h,the dosage of catalyst for 10.0%and40:1 methanol/oil?V/W?ratio,the highest yield of biodiesel was 5.17%.After reusing for 4 cycles,the catalyst exhibited a rather high biodiesel yield?above 80%?.?7?The cost of solid acid catalyst is only 1/2 of that of concentrated sulfuric acid as catalyst in producing biodiesel from primary sludge,and the energy consumption cost is only 1/3 of that of concentrated sulfuric acid as catalyst.The catalytic efficiency of solid catalyst is 17 times that of concentrated sulfuric acid as catalyst.?8?Primary sludge is the better raw material for biodiesel production.The raw material cost of biodiesel from yeast is slightly higher than that from sludge,whichwould consume more energy?6.9kWh?to produce 1g biodiesel from yeast than from sludge.Moreover,the time spent in producing biodiesel from yeast is three folds of that from sludge.