Upgrading Of Vegatable Pitch For Fuel Oil

Energy crisis and environmental pollution have brought great instability to human society.As a renewable resource,vegatable pitch has good characteristics including green and environmental protection,wealth of sources.So vegetable pitch used as fuel oil is an effective method for alleviating the problems above.In this paper,two problems were discussed.First,potassium content is high;Second,calorific value is low,viscosity is high,oxygen content is high and so on.Main contents and conclusions were as follows:(1)Determination content of potassium ion.The pretreatment of vegatable pitch materials was carried out by dry digestion and microwave digestion respectively.ion chromatography was used as determining the content of potassium.The ion chromatographic separation was suitably carried out when column temperature was30?,using 1.7mmol/L HNO3 as mobile phase at flow rate of 0.9ml/min.Over this detection conditions,the recovery rate of dry and microwave were 0.64% and 0.84%,respectively.And the RSD had a range from 97%~101%.The result shows that these two pretreated methods haven't lost potassium,and they are both accurate.(2)Removal of potassium ions.Firstly,removal of potassium was carried out by glycerol extraction.When the stirring rate was constant,the suitable conditions were as follows: the ratio of vegatable pitch and glycerin was 5:1,stirring time was 10 min,temperature was 100 ? and standing settling time was 300 min.The removal of potassium was 76.0% after first cross-flow extraction.And depotassium rate was 92.3%after tertiary cross-flow extraction.Secondly,removal of potassium ions was tested by dilute acid extraction.Potassium could be almost completely removed by using0.1mol/L dilute sulfuric acid according to the stoichiometric ratio of acid-base reaction.(3)Pyrolysis vegatable pitch by molten salts.The experimental research of vegatable pitch pyrolysis was carried out in a pyrolytic reactor with mixed molten saltsLi2CO3-Na2CO3-K2CO3?Through comparing the yield and composition distribution of bio-oil and pyrolytic gas,the appropriate pyrolysis temperature was 540? and feed rate was 1.4g/min under no carrier gas.Bio-oil yield was 69.9wt.%.Main compositions of bio-oil were alkanes(14.44%),alkenes(48.32%)and aromatics(9.14%).Oxygenated chemicals like ketones and esters accounted for 28.11%.Compared with vegatable pitch,bio-oil had lower viscosity,higher calorific value,lower metal content,gasoline components and diesel components were produced together,so the quality was greatly improved.Gas yield was 16.74 wt.%.According to gas products,H2,CO,CH4,C2-4hydrocarbon could be used as a gas fuel except CO2.Pyrolysis without melting salts had higher content of esters in bio-oil,lower content of CO2 in gas products.It means molten salts have the ability of decarboxylation and degreaese.