Continuous flow method and apparatus for making biodiesel fuel

Abstract

In an economical and efficient process and apparatus for producing biofuel from waste oil, such as vegetable oils and animal fats, waste oil is esterified with alcohols to produce alcohol esters and the by-products of the transesterification reaction are recovered. Static pressure may be used as well as continuous flow-through reaction vessels and separation tanks without the need for additional pumps. There may also be specialized reaction tanks that have vertical rotating feed tubes having separators and inlet and outlet openings. The method and device achieves efficient production of biofuel while employing reaction and mixing tanks having a limited size, which in turn permits a smaller plant layout or “footprint”. For example, the largest tank may be in a size of about 36/100,000 times the desired plant output in gallons per year. The benefits of the process and apparatus include minimal space for a plant; minimal on-site feedstock needed therefore minimal on-site storage is needed; minimal capital costs to build a plant e.g., reduction by about fifty to sixty five percent (50 to 65%); reduction in construction time from typically over one year to under three months in many plants; minimal energy usage, e.g., reduction by about sixty percent (60%); minimal labor costs due to the automatic continuous flow; minimal pumps needed thereby reducing pump operation and maintenance costs; environmentally friendlier and safer plant design; and due to smaller plant footprint, lower capital cost and minimal construction time enables site selection much nearer to the raw material supplies, thereby minimizing or even eliminating transportation costs for yellow grease or vegetable oil.

1 . A process of obtaining biofuel oil from oil byproducts, wherein the process uses a continuous flow of the oil byproducts through a series of mixing tanks and separation tanks.  
     
     
         2 . The process of  claim 1  wherein the process mixes sulfuric acid and methanol with the oil byproducts at a temperature of about 180° F.  
     
     
         3 . The process of  claim 1  wherein the flow rate through each of the mixing tanks is about two gpm and the flow rate to each of the separation tanks is about the same.  
     
     
         4 . The process of  claim 1  wherein the mixing tank is heated.  
     
     
         5 . The process if  claim 1  wherein the separation tank is heated.  
     
     
         6 . A process of continuously flowing liquid from one tank to a successive tank by pumping liquid into the first tank and using static pressure to propel liquid to the next tank.  
     
     
         7 . The process of  claim 6  wherein the tanks are open.  
     
     
         8 . A mixing tank comprising: 
 a housing;    multiple vertical chambers defined by separators;    a mixing blade in each chamber;    an input pipe passing through all of the chambers;    wherein each mixing blade is attached to the input pipe and the input pipe is rotated.    
     
     
         9 . The tank of  claim 8  wherein the separators are attached to the input pipe, and slant upward and outward.  
     
     
         10 . The tank of  claim 8 , wherein the pipe has an inlet opening in each chamber above the mixing blade, and an outlet opening below the blade, and being plugged between the inlet and outlet.  
     
     
         11 . A plant for production of biofuel, wherein a first and second reaction vessel and a first and second separation tank are located in a two by two layout.  
     
     
         12 . A plant for production of biofuel, wherein the plant can produce about one million or more gallons per year from four tanks, and largest tank having a capacity of about 360 gallons, for the fatty acid reduction and esterification reactions.  
     
     
         13 . The plant of  claim 12 , wherein each tank is supported on a stand of about four feet by four feet.  
     
     
         14 . The plant of  claim 12 , wherein the four tanks have a footprint of less than or equal to sixty four square feet.  
     
     
         15 . The plant of  claim 12  wherein feedstock is supplied to the reaction vessel at about two gallons per minute.  
     
     
         16 . The process of  claim 1  further comprising a step of heating at least one of the separation tanks.  
     
     
         17 . The process of  claim 16  further comprising a step of heating using a water jacket on each tank.  
     
     
         18 . The process of  claim 17  wherein there is a step of maintaining constant pressure from the water jacket on at least one tank.  
     
     
         19 . The process of  claim 1  further comprising the steps of mixing sulfuric acid with methanol in a first tank, flowing the sulfuric acid and methanol into a second tank and allowing them to settle out, and oil to settle on top thereof, allowing the oil to flow to a third tank and mixing it with potassium hydroxide and methanol, and allowing them to settle out in a fourth tank.