| Bio-diesel is a kind of environmental friendly renewable energy from biomass, whose use can relieve human-beings from the dependence of fossil fuels and greatly eliminate environmental pollution.The methods of direct blending, micro-emulsion, thermo splitting, transesterification, micro-algae and etc., are the recent world-wide bio-diesel manufactured methods, among which the method of transesterification is the most applied.The thesis analyzed the advantages and disadvantages of these methods and alkali catalysis was used on the present situation of the laboratory. Sodium hydroxide catalyzes palm oil and ethanol to produce bio-diesel. The indexes of the molecular ratio between oil and ethanol, weight percentage of catalysis, reaction period, temperature and blending speed were considered to stir the output ratio of bio-diesel.The result indicated that the best reaction conditions were bellow: the molecular ratio between oil and ethanol (6:1), weight percentage of catalysis (0.5%), reaction period (3h), temperature (40℃) and blending speed (1000r/min), on the condition of which the output ratio of bio-diesel reached 96.5%. GC and GC-MS were used to analyze the product, and the results indicated the main element was ethyl esters, ethanol can not be checked out. The carbon chain was from C18-C20, similar with that of fossil diesel. Parts of physic chemical indexes were also analyzed, apart from freezing point, the other indexes were confessed to "ESTABLISHMENT OF NATIONAL STANDARD OF BIODIESEL BLEND STOCK FOR DIESEL ENGINE FUELS" (GB/T20828-2007).D.I. diesel engine with two cylinders was used to test the bio-diesel and its mixtures with diesel, among which dynamic performance, economic properties and emission properties were tested and compared. The results indicated that the general agreement among bio-diesel, diesel and their mixtures in all tested properties was proved and little difference still existed. The relevant references reported the same results. Such indicated that the manufacture indexes optimized were rational.The engine test-bench achieves bellow results:(1) Full load speed characteristics:the most output torque and power in varies rotational speed of any blending rate of bio-diesel are lower with higher fuel consumption than NO.0 diesel. Respectively, the average power of the blended bio-diesel B20, B50 and B100 dropped by 2.4%,3.8% and 9.0%; the specific diesel consumption of that mounted up by 3.2%,5.4%, and 13.2%. The smoke of B50 and B100 decreased. Especially B100 decreased about 57.5%, comparing with NO.0 diesel. The emission temperature of B50 and B100 obviously got down. The result indicated that whilst the engine used bio-diesel, its properties of power and economy slightly decreased and that of emission was improved.(2) Load Characteristics:The specific diesel consumption increased with more blending rate of bio-diesel. On rotational speed of 1600r/min, the each specific diesel consumption of B20, B50 and B100 is averagely higher than NO.0 diesel by about 1.8%,6.3% and13.3%. Results and the value difference of specific diesel consumption on 2400 r/min were similar with on 1600r/min.The data of engine test-bench indicated that the power and economical properties of the blending bio-diesel were worse than NO.0 diesel and the smoke data of that was not obviously lower than that of NO.0 diesel during the load characteristics experiments. In order to solve these problem, the thesis preliminarily developed the bio-diesel emulsion. The below was the exploring results of bio-diesel emulsion. Emulsified oil from bio-diesel & NO.0 diesel was more stable than that from palm oil & NO.0 diesel. The best HLB value of bio-diesel & NO.0 diesel mixture was from 6.44 to 8.58. Duration before phase splitting was 120h. The thesis found that the optimized water adding content was 5% when researching on the impacts of the stability of bio-diesel & NO.0 diesel emulsified oil. |
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