Fuel for diesel engines in microemulsion form and method for preparing the same

Abstract

A fuel in microemulsion form, particularly for Diesel engines, comprising a primary fuel constituted by mineral oils and/or vegetable oils, water, a lipophilic emulsifying agent (W/O) and a hydrophilic emulsifying/detergent agent (O/W), wherein the hydrophilic emulsifying/detergent agent (O/W) is a mixture of two or more polyol esters having different molecular weights.

1 . A fuel in microemulsion form, particularly for Diesel engines, comprising a primary fuel constituted by mineral oils and/or vegetable oils, water, a lipophilic emulsifying agent (W/O) and a hydrophilic emulsifying/detergent agent (O/W), wherein the hydrophilic emulsifying/detergent agent (O/W) is a mixture of two or more polyol esters having different molecular weights.  
     
     
         2 . The fuel according to  claim 1 , wherein said lipophilic emulsifying agent (W/O) has a HLB value between 4 and 6.  
     
     
         3 . The fuel according to  claim 1 , wherein said hydrophilic emulsifying/detergent agent (O/W) has a HLB value higher than 12.  
     
     
         4 . The fuel according to  claim 1 , wherein the microemulsion has an average microcell diameter of less than 0.15 μm.  
     
     
         5 . The fuel according to  claim 1 , comprising 10 to 15% by weight of water relative to said primary fuel.  
     
     
         6 . The fuel according to  claim 1 , comprising 50 to 95, preferably 55 to 75, parts by weight of lipophilic emulsifying agent relative to the total weight of the hydrophilic emulsifying/detergent agent and of the lipophilic emulsifying agent.  
     
     
         7 . The fuel according to  claim 1 , comprising 50 to 5, preferably 45 to 25, parts by weight of hydrophilic emulsifying/detergent agent relative to the total weight of the hydrophilic emulsifying/detergent agent and of the lipophilic emulsifying agent.  
     
     
         8 . The fuel according to  claim 1 , wherein said lipophilic emulsifying agent is a fatty ester of sorbitol.  
     
     
         9 . The fuel according to  claim 8 , wherein said lipophilic emulsifying agent is selected from the group consisting of sorbitan monooleate ethoxylate (20), sorbitan dioleate, sorbitan trioleate, sorbitan hexaoleate, sorbitan monolaurate, sorbitan monolaurate ethoxylate (20), sorbitan monopalmitate, sorbitan monostearate, sorbitan monostearate ethoxylate (20), sorbitan monostearate-palmitate and sorbitan tristearate.  
     
     
         10 . The fuel according to  claim 1 , wherein said hydrophilic emulsifying/detergent agent (O/W) is a mixture of glycol esters, particularly a mixture of glycol esters containing polyglycol oleate.  
     
     
         11 . The fuel according to  claim 1 , wherein said hydrophilic emulsifying/detergent agent (O/W) is a mixture of esters selected from the group consisting of PEG esters other than polyglycol oleate, such as for example complex esters and compound esters, glycerin esters, glycol esters, monoalcohol esters, sorbitol POE esters, polyalcohol esters, and trimethylpropane esters.  
     
     
         12 . The fuel according to  claim 11 , wherein said hydrophilic emulsifying/detergent agent (O/W) is a mixture of esters selected from the group consisting of diethylene glycol monococoate, PEG 200 cocoate, PEG 400 cocoate, diethylene glycol monooleate, PEG 200 monooleate, PEG 300 monooleate, PEG 400 monooleate, PEG 600 monooleate, PEG 1000 monooleate, PEG 40000 monooleate, PEG 6000 monooleate, PEG 400 oleate, dipropylene glycol monooleate, PEG dioleate, PEG 400 dioleate, PEG 600 dioleate, diethylene glycol monolaurate, PEG 300 monolaurate, PEG 400 monolaurate, PEG 400 dilaurate, diethylene glycol monostearate, PEG 200 monostearate, PEG 300 monostearate, PEG 400 monostearate, PEG 15000 monostearate, PEG 40000 monostearate, PEG POE 40 stearate, PEG 400 distearate, PEG 600 distearate, PEG 2000 distearate, and PEG 6000 distearate.  
     
     
         13 . The fuel according to  claim 1 , wherein the hydrophilic emulsifying/detergent agent is a mixture of esters of PEG 200 and PEG 6000.  
     
     
         14 . A method for preparing a fuel according to  claim 1 , comprising the steps of preparing a hydrophilic emulsifying/detergent agent (O/W) by mixing two or more esters of polyols, providing a lipophilic emulsifying agent (W/O), and introducing said hydrophilic emulsifying/detergent agent (O/W) and said lipophilic emulsifying agent (W/O) separately or premixed into a primary fuel constituted by mineral oils and/or vegetable oils and/or mixtures thereof.