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.

Description

CROSS-REFERENCE [0001] This application claims the priority of previously filed U.S. provisional patent application Ser. No. 60 / 317,090 filed Sep. 4, 2001, incorporated by reference herein.BACKGROUND OF THE INVENTION [0002] 1 . Field of the Invention [0003] The present invention is directed to a process and apparatus for producing “biofuel” from oil or waste oil such as “yellow grease” (also known as tallow or used oil from food). [0004] 2. Description of the Related Art [0005] A number of approaches have been taken to produce “biofuels” from waste oils or “yellow grease” (also known as tallow or used oil from food). These greases include fat grease, chicken fat, and vegetable oils. Generally, the method involves obtaining a fatty acid alkyl ester by transesterification of monoglycerides, diglycerides and triglycerides with alkyl alcohol. For example, the yellow grease may be heated and then mixed with sulfuric acid and methanol in a large tank or reaction vessel. The acid and metha...

AI Technical Summary

Benefits of technology

[0012] In one embodiment, the present invention achieves continuous flow through all the reaction vessels and separation tanks without the need for additional pumps. The invention preferably employs preferably closed tanks (though preferably not sealed) to provide for methanol recovery, and may include vertical rotating feed tubes having separators and inlet and outlet openings. These features permit production of a larger quantity of biodiesel fuel while employing reaction and mixing tanks having a limited size, which in turn permits a dramatically smaller plant layout or “footprint”. Further, the process preferably pre-mixes the catalyst and methanol, but does not require pre-mixing prior to adding the catalyst to the oil or a means for actively removing heat from the system.

Problems solved by technology

This is very difficult to do in large tanks without incorporating very expensive heating and cooling units.

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