Experiment Study On Production Process And Emission Performance Of Pepper Seed Biodiesel

As a kind of green and renewable energy, it is of great strategic meanings for our country to develop biodiesel to alleviate energy crisis,mitigate environmental pollution and promote sustainable growth of economy. The subject mainly does experimental study on the production process of pepper oil biodiesel,best fuels blend-ratio of 0# petroleum diesel with pepper biodiesel,and NOX emissions reduction of diesel engine when it uses pepper seed biodiesel and blended fuels composed of petroleum diesels with pepper seed biodiesel.In this paper,the biodiesel was produced via esterification or transesterification by using pepper oil and methanol in the presence of sulfuric acid or potassium hydroxide as catalyst respectively,and its process technological conditions were investigated in detail.When the concentrated sulfuric acid was used as the catalyst , the optimum technological conditions were as following:the molar ratio of alcohol to pepper oil was 18:1, 0.6% of catalyst concentration,reaction temperature was 90℃and reaction time was 3 hours. The yield of transesterfication reached to 84.5% under the optimum technological conditions.However, when the potassium hydroxide was used as the catalyst to make biodiesel, the first step was to drop the acidity of the pepper oil. And in this study, we used two methods: pre-esterification and physical extraction.For the pre-esterification to reduce the acidity of the pepper oil, the optimum conditions were as following: the molar ratio of alcohol to pepper oil was 24:1, 7% of catalyst concentration,reaction temperature was 110℃and reaction time was 4 hours. Under the reaction, the value of the pepper oil was reduced from 63.5 mg(KOH)/g to 8.2 mg(KOH)/g.By the physical extraction method: at 20℃, the volume ratio of alcohol to pepper oil was 3:1. And by 3 extractions, the acidity was dropped to 1.5 mg(KOH)/g. Compared to the pre-esterification treatment, the physical extraction result is better, and it meets the requirement of catalyst acidity condition: lower than 2 mg(KOH)/g. At the same time, this method is easier to operate.And then, by changing the molar ratio of methanol to oil, catalyst amount, reaction time and reaction temperature, we carried out the comparative experiments. The best reaction conditions was got as following: the molar ratio of alcohol to pepper oil was 12:1, 1.2% of catalyst concentration,reaction time 45 min and temperature 60~65℃, and the output reached to 92.1%.By the study above, we developed a set of optimum process of making biodiesel, and it was mainly divided into four stages. Acidity-reduction phase: by physical extraction with methanol; Drying phase: by using silica gel desiccant to dry the pepper oil and methanol; Transesterification phase: under the optimum conditions; Post-processing phase: by esterification of the free fatty-acids to generate pepper biodiesel.By the engine test, the best blend-ratio of the pepper biodiesel with 0# diesel was studied, and then we operated the experiment of reducing NOx emissions when diesel engine consumed pepper biodiesel and its blended fuels.The blend- ratio test results indicated that: the power reduced 1.8 by burning the B30 compared to the B0 oil; the fuel consumption rate was lower than B0 at 1000-1400 r/min, but when the rotary speed exceeded 1400 r/min, the consumption was higher than the B0 oil.Two ways were adopted in the experiment to reduce NOX emission when diesel engine used biodiesel and blended fuels: blending ethanol with pepper biodiesel and changing fuel supply advance angle of diesel engine, and following conclusions could be got: compared with B100, E5B95 reduced both smoke and NOX emissions of diesel engine. NOX emission concentration drop of 6.39% in the speed of 1400 r/min,and 2.42% in the speed of 2000 r/min. Decreasing fuel supply advance angle was a good way for diesel engine to reduce NOX emission,when fuel supply advance angle was delayed 3°CA and 6°CA, the biggest drop of NOX emission were 26% and 40%. Based on overall consideration on emissions,dynamics and economy factors ,it could be known that the best fuel supply advance angle ranged between 14°CA and 17°CA when diesel engine consumed E5B95.