1. A method for producing a fatty acid alkyl ester comprising subjecting a starting oil to an ester exchange reaction with a lower alkyl alcohol in the presence of a catalyst to generate a fatty acid alkyl ester, wherein said ester exchange reaction step is carried out in a homogeneous phase system by adding an organic solvent selected from acetone, isopropanol and a mixture thereof to a reaction system.
2. The method for producing a fatty acid alkyl ester according to claim 1, wherein said starting oil is a vegetable oil.
3. The method for producing a fatty acid alkyl ester according to claim 1, wherein said catalyst is any one of an alkaline catalyst, an acid catalyst, an enzyme or a solid catalyst comprising an ion exchange resin.
4. The method for producing a fatty acid alkyl ester according to claim 1, wherein said ester exchange reaction step is a step for mixing a solution comprising the starting oil and the organic solvent with a solution comprising the lower alkyl alcohol and the catalyst.
5. The method for producing a fatty acid alkyl ester according to claim 4, wherein said mixing of the solutions is carried out by adding the solution comprising the lower alkyl alcohol and the catalyst in multiple stages.
6. The method for producing a fatty acid alkyl ester according to claim 1, comprising, after completion of said ester exchange reaction step, a leaving and separating step for leaving a reaction solution containing the fatty acid alkyl ester and obtained by the ester exchange reaction step to separate the solution into a fatty acid alkyl ester phase comprising the fatty acid alkyl ester, the lower alkyl alcohol and the organic solvent and a glycerin phase.
7. The method for producing a fatty acid alkyl ester according to claim 1, comprising a step for recovering the lower alkyl alcohol and the organic solvent from the fatty acid alkyl ester phase.
8. The method for producing a fatty acid alkyl ester according to claim 7, wherein the recovered lower alkyl alcohol and organic solvent are added to the solution comprising the starting oil and the organic solvent.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A process for incinerating a solid particulate material comprising the steps of:
introducing a feed mixture into a first combustion zone of a furnace, said furnace having a lower end and an upper end defining a primary combustion chamber, said feed comprising said solid particulate material and a first source of combustion air in an amount less than a stoichiometric amount needed to completely incinerate said particulate material; and
incinerating said solid particulate material in a first incinerating stage in said primary combustion zone in an atmosphere containing less than a stoichiometric amount of air to inhibit the formation of sintered ash.
2. The process of claim 1, wherein said furnace includes a burner and said process comprises directing hot combustion gases into said combustion zone to incinerate said solid particulate material.
3. The process of claim 1, wherein said solid particulate material is dried biological waste or sludge particles.
4. The process of claim 1, further comprising feeding a second source of air into a second combustion zone of said primary combustion chamber to cool said secondary combustion zone, said second source of air being fed into said secondary combustion zone at a location above said feed of said first source of combustion air.
5. The process of claim 4, wherein said second source of air is moist air having a lower oxygen content than said first source of air to maintain said second combustion zone at about 850 C.
6. The process of claim 5, wherein said second source of air is recycled air from a sludge drying assembly.
7. The process of claim 4, wherein said furnace is a cyclone furnace and said process comprises feeding a third source of air into a center portion of said first combustion chamber of said furnace to cool said first combustion zone, wherein said third source of air is fresh air at ambient temperature.
8. The process of claim 7, wherein said furnace includes a feed pipe extending through said primary combustion chamber in an axial direction with respect to said furnace and having a plurality of outlet openings, said process comprising feeding said third source of air through said feed pipe into said primary combustion chamber.
9. The process of claim 8, wherein said outlet openings of said feed pipe are spaced along a length of said feed pipe for directing said third source of air radially outward.
10. The process of claim 7, wherein the amount of said second source of air fed to said furnace is different from said third source of air.
11. The process of claim 4, wherein said furnace has an exhaust gas outlet positioned in an upper end of said primary combustion chamber, a first annular wall surrounding said exhaust gas outlet and extending axially into said first combustion zone, and a second annular wall concentric to said first annular wall and forming an annular air passage between said first and second annular walls, said process further comprising feeding a third source of fresh air through said annular air passage downwardly into said first combustion chamber.
12. The process of claim 1, comprising feeding said first source of air into said furnace in an amount to incinerate said solid particulate material at a predetermined rate.
13. The process of claim 4, comprising feeding said second source of air into said furnace in an amount based on a capacity of said furnace.
14. The process of claim 1, wherein said furnace is a cyclone furnace, said process comprising feeding said feed mixture tangentially into said furnace.
15. The process of claim 1, comprising feeding a further source of air into said furnace at a location below said feed mixture.
16. The process of claim 1, comprising maintaining said combustion zone at a temperature of about 850 C.
17. The process of claim 4, wherein said primary combustion chamber of said furnace includes an exhaust gas outlet, said first combustion zone being spaced from said exhaust gas outlet, said process comprising feeding said second source of air into said second combustion zone, wherein said second combustion zone is positioned between said first combustion zone and said exhaust gas outlet, and said second source of combustion air is provided to supply a stoichiometric excess of oxygen to said second combustion zone to provide complete combustion of said solid particulates.
18. An apparatus for incinerating a solid particulate material comprising:
a furnace wall defining a primary combustion chamber and having a lower end and an upper end;
a burner coupled to said furnace wall for introducing hot combustion gases into said primary combustion chamber;
a first feed inlet for feeding a feed mixture into a first combustion zone in said primary combustion chamber, said feed mixture including a solid particulate material and a first source of combustion air in less than a stoichiometric amount needed for complete combustion of said solid particulate material; and
a second feed inlet for feeding a second source of air into said primary combustion chamber.
19. The apparatus of claim 18, further comprising a feed pipe extending axially through said primary combustion chamber for supplying a tertiary source of air into said primary combustion chamber in an amount to maintain said primary combustion chamber at a temperature of about 850 C.
20. The apparatus of claim 19, wherein said feed pipe extends through a center of said primary combustion chamber, said feed pipe including a plurality of air outlet openings spaced along a length of said combustion chamber for feeding said tertiary source of air radially outward into said primary combustion chamber.
21. The apparatus of claim 18, wherein said second feed inlet is spaced upward from said first feed inlet with respect to said upper end of said furnace.
22. The apparatus of claim 18, further comprising an annular air inlet positioned in said primary combustion chamber for directing an annular column of fresh air downwardly into said primary combustion chamber.
23. The apparatus of claim 22, said primary combustion chamber having a central opening in said upper end communicating with a secondary combustion chamber, and said annular air inlet surrounding said central opening.
24. The apparatus of claim 23, wherein said annular inlet comprises an inner annular wall and an outer annular wall, said inner and outer annular walls having a length to extend toward said lower end beyond said first feed inlet.
25. The apparatus of claim 18, wherein said furnace is a cyclone furnace and said first inlet feeds said feed mixture tangentially into said furnace.
26. A furnace for incinerating a solid particulate material comprising:
at least one side wall, a bottom wall, a top wall, and an intermediate wall extending substantially perpendicular to said side wall in an inward direction toward an axial center of said furnace, said intermediate wall having a throat opening concentric with a center axis of said furnace and defining a primary combustion chamber in a lower portion of said furnace and a secondary combustion chamber in an upper portion of said furnace;
a feed inlet device in said side wall for feeding a feed mixture tangentially into said primary combustion chamber, said feed mixture including a solid particulate material and combustion air in less than a stoichiometric amount needed for complete combustion of said particulate material; and
at least one feed pipe for feeding a supply of fresh air into said center of said primary combustion chamber in an amount to cool said primary combustion chamber at a temperature of about 850 C.
27. The furnace of claim 26, wherein said feed pipe comprises an annular pipe having an annular outlet surrounding said opening in said intermediate wall for feeding fresh combustion air into said primary combustion chamber a substantially downward direction toward said bottom wall.
28. The furnace of claim 27, wherein said annular pipe has a length extending axially into said primary combustion chamber beyond said feed inlet device and for directing said combustion air in a downward direction.
29. The furnace of claim 27, wherein said annular pipe comprises an inner wall forming an axial passage between said primary combustion chamber and said secondary combustion chamber.
30. The furnace of claim 29, wherein said annular pipe further comprises an outer wall forming said annular outlet between said inner and outer walls for directing a substantially annular stream of air into said primary combustion chamber.
31. The furnace of claim 27, further comprising a cylindrical pipe concentric with said annular pipe and extending through said first feed pipe for feeding air into said primary combustion chamber.
32. The furnace of claim 31, wherein said cylindrical pipe includes a cylindrical side wall having a plurality of outlet openings for feeding said air in an outward direction with respect to said cylindrical side wall into said primary combustion chamber.