process for conversion of low cost and high ffa oils to biodiesel

Abstract

The present invention describes a process for converting high free fatty acid containing feed stocks (FFA 20-85%) like palm fatty acid distillate (PFAD), restaurant grease, waste cooking oil, Soya deodistillate, acid oil, jatropha curcas oil, mohua oil etc. to biodiesel, which involves esterification of FFA containing oil with lower alcohols like methanol, ethanol, propanol etc. in presence of macro reticular and gel type acidic heterogenous resin as catalyst to bring down acid value in the range of 1-2 mgKOH/g followed by transesterification in presence of homogeneous basic catalyst metal oxides, hydroxides and alkoxides like sodium hydroxide, potassium hydroxide, sodium methoxide, potassium methoxide etc. and separation of biodiesel and glycerine.

1 . A process for converting high free fatty acid containing feed stocks (FFA 20-85%) into biodiesel which comprises:
 a. providing feed stocks containing 20-85% FFA without pretreatment or purification;   b. esterifying the feed stocks with lower alcohols in the presence of macroreticular and gel type acidic heterogeneous resin as catalyst;   c. heating the reactants of step (b) at a temperature in the range of 55-65° C. followed by mechanical stirring for a period of 8 to 10 hours to obtain esterified oil;   d. subjecting the esterified oil as obtained from step (c) to transesterification in the presence of homogeneous basic catalyst and methanol;   e. separating product as obtained from step (d) into upper layer biodiesel and lower layer glycerol followed by recovering of methanol;   f. washing the biodiesel layer as obtained from step (e) with hot water followed by drying to obtain biodiesel.   
     
     
         2 . A process according to  claim 1 , wherein the feedstocks containing 20-85% FFA are selected from the group consisting of palm fatty acid distillate (PFAD), restaurant grease, waste cooking oil, Soya deo distillate, acid oil, jatropha curcas oil and mohua oil. 
     
     
         3 . A process according to  claim 1 , wherein the lower alcohols used is methanol, ethanol or propanol in the ratio of 3:1 to 35:1 depending upon feedstock. 
     
     
         4 . A process according to  claim 1 , wherein the acidic heterogeneous resin catalyst is provided either in a jacketed glass reactor with stainless steel basket or used directly with stirring for esterification process without neutralization or pretreatment. 
     
     
         5 . A process according to  claim 1 , wherein the acidic heterogeneous resin catalyst is used repeatedly for 4-5 cycles of the reaction. 
     
     
         6 . A process according to  claim 1 , wherein the acidic heterogeneous resin catalyst used for esterification is selected from the group consisting of Tulsion-42 and Indion-130. 
     
     
         7 . A process according to  claim 1 , wherein the catalyst Tulsion-42 is used in the range of 5-20% by weight of the feed stocks and Indion-130 is used in the range of 5-25% by weight of the feed stocks. 
     
     
         8 . A process according to  claim 1 , wherein homogeneous basic catalyst used for transesterification is selected from the group consisting of sodium hydroxide, potassium hydroxide, sodium methoxide and potassium methoxide. 
     
     
         9 . A process according to  claim 1 , wherein the transesterification is carried out at a temperature in the range of 55-70° C. for a period of 1 to 2 hrs.