Formation Process of Toxic Substances from Biomass Fuel

生物质燃料是石油的一种很好的替代燃料，因为它是可再生的，而且在整个生态系统循环中二氧化碳的排放很少。从植物油中提取的甲基酯化燃料对柴油发动机特别有益，因为它几乎可以达到与使用汽油所达到的发动机性能，但废气要少得多。然而，由于酯化燃料中的氧分子含有氧气，因此使用酯化燃料的柴油发动机比使用汽油作为燃料的柴油发动机排放出更多含氧有毒物质的风险。根据实验结果，可以肯定地说，用酯化燃料制备汽车用柴油是可行的。植物油的组成成分和酯化率的差异将在甲酯燃料中反映为其成分的差异。然而，这不会对发动机性能和排放特性产生任何大的影响。对于甲醇、甲醛、乙醛、丙烯醛等特定有害物质的排放，发现与脂肪酸中构成甲酯的双键数有关。与汽油相比，无论燃烧室类型如何，甲酯燃料的废气中甲醇、甲醛、丙烯醛、苯等特定有害物质的含量都是汽油的1、2 ~ 3倍。在中低负荷范围内，直喷式发动机排放了大量的颗粒物。有问题的颗粒中有很大一部分由软质成分组成。然而，使用IDI发动机，甲酯燃料和轻质油之间的颗粒排放没有显着差异。我们需要对丙醛引起的天妇罗小虫采取对策。

Biomass fuel is a good substitute fuel for petroleum because it is reproducible and because there is very little emission of CO_2 throughout the ecosystem cycle. Methyl-esterificated fuel produced from vegetable oil is particularly beneficial for diesel engines because almost the same engine performance as that achieved by the use of gas oil is possible but there is much less exhaust smoke. However, since oxygen molecules in esterified fuel contain oxygen, there is a risk that more toxic substance containing oxygen will be emitted from a diesel engine in which esterified fuel is used than from an engine in which gas oil is used as fuel.As the experiment result, it is safe to say that a diesel fuel for the automobile van be made from esterified fuel. The differences in the constituent component and esterification ratio of the vegetable oil will be reflected in the methyl eater fuel as the difference in its component. However, this will not make an impact upon engine performance and emission characteristics in any great way. As for the emission of such specified harmful substances as methanol, formaldehyde, acetaldehyde and acrolein etc, the number of dublebonds in the fatty acid that constitute methyl eater was found to be responsible.In comparison with gas oil, regardless of the combustion chamber types, the methyl ester fuel had 1,2 to 3times more of specified harmful substance such as methanol, formaldehyde, acrolein and benzene in the exhaust gas. The DI engine was found to emit a large quantity of particulates in the low to middle load range. A large portion of the particulates in question consist of SOF components. However, with the IDI engine, there was no significant difference in the emission of particulates between methyl ester fuel and light oil. We need to take countermeasures against the tempura small which is caused by propionaldehyde.