| Energy crisis and environment problem always come out together, so it is impossible to resolve them separately. Rush development of society economy results in a great challenge to our environment and environment problem has become a global one. China is a large oil-imported country and rush economy rising needs more and more oil to support. As we know, in order to get energy resource, army conflicts never stop all over the word, which results in international oil price rising up and up. Energy safety threatens national strategic safety seriously. It is favorable to develop ethanol as one of alternative fuels. (1) As one of alternative fuels, ethanol can resolve domestic oil shortage partly and reduce the dependence on oil importing effectively. (2) Ethanol is an oxygenic fuel, which has positive effects on engine emissions. Ethanol can improve engine emissions and reduce pollutants. (3)Ethanol can be made by biomaterial such as sugarcane , corn and crop cane etc. So we can view ethanol as a regenerated fuel, which can reduce greenhouse gases. Otherwise, ethanol also is a chemosynthesis product made by coal or natural gas. There is a remarkable coal storage and corn production in China. So ethanol as vehicle alternative fuel has a great potential in China. Ethanol has already applied to gasoline engine in USA. and Brazil, which has got great achievement . We also find some cars using gasohol in China now. However, only applying ethanol to gasoline engines is not enough. It can not reduce the dependence on oil importing. Because of the limit of oil refine technology, the production of diesel and gasoline from the petrol oil is proportioned. So it will be useful, only when ethanol substitutes for gasoline and diesel in a certain proportion. So ethanol applying to diesel engines is much meaningful and necessary. As a prospecting fuel, ethanol plays an important role in future alternative fuels. But some researches show that ethanol increases ethanol and acetaldehyde emissions in engine exhaust. One of the goals in the work is to set up one efficient test system to analyse the ethanol and the acetaldehyde in the exhaust. On one hand it can give help to the basis theory study on ethanol combustion in engines, on the other hand it can supply the data base and technology help for the future laws. So the work is necessary and positive for ethanol fuels application in future. Gas chromatography (GC) technology is a very important analysis way, which is used to analyse ethanol and acetaldehyde in the experiment. Different matters have different sorption in two phases . when the two phases move convectively , the matters will separate from each other one by one as time goes. As one of important analysis ways, GC method has been applied to broad and different fields. Its most important advantage is that it can separate the different fractions from each other .so it is usually applied to analyse the complex mixture. In engine exhaust testing, usually we can get the total hydrocarbon(THC). But, we do not know the Ethanol and the Acetaldehyde content. The Chromatograph technology can resolve the problem, which is very suitable to test the Ethanol and the Acetaldehyde emissions in the engine exhaust. The work is helpful to study the theory of ethanol combustion in engines. On the basis of the research materials, we have set up a complete ethanol and Acetaldehyde test system including sampling system and GC analysis system. Both of acetaldehyde and ethanol are soluble in the water. Using the deionized water as solution, the author set up a two-stage sampling system , witch is simple and steady. Deionized water is in a impinger bathed in ice water. The samples obtained by the way are easy to store. The sampling absorptivity is more than 96%.The study also completed the calibration of shimadzu GC2010 including making standard samples and making quantitative curves.The capillary column is PEG-20M 15m(length) ×0.25mm(id) ×0.53μm(film), which is polar one. The fixed phase is PEG-20M . When the exhaust sampling volume is 6 liter and GC signal/noise ratio is 3:1, the detect limit is 0.1 ppm in the exhaust. If we increase the sampling exhaust volume ,we can get the lower detect limit. Finally, the author analysed the exhaust samples by Shimadzu GC2010 and achieved a great success. To make sure the accuracy, the author introduced a few coefficients to modify the parameters in the sampling system, such as dilution coefficient k1 and sampling volume modified coefficient k 2. The author completed these... |
PDF Full Text Request