METHOD FOR UPGRADING LOW-VALUE AND WASTE FATS, OILS, AND GREASES
The present technology provides a method that includes contacting a composition with a caustic solution to produce a caustic-treated composition; combining the caustic-treated composition with silica particles to produce a slurry; and removing the silica particles from the slurry to produce a treated composition; wherein the composition includes one or more of animal fats, animal oils, plant fats, plant oils, vegetable fats, vegetable oils, greases, and used cooking oil and the composition includes: at least about 10 wppm of total metals, at least about 8 wppm of phosphorus, at least about 10 wppm of chlorine, at least about 10 wppm of sulfur, at least about 20 wppm of nitrogen, at least about 5 wt. % of free fatty acids; and has an acid number from about 10 mg KOH/g to about 150 mg KOH/g, and the silica particles has a particle size from about 10 microns to about 50 microns, a BET surface area from about 200 m 2 /g to about 1000 m 2 /g.
1 . A method comprising:
free fatty acid (FFA) stripping of a starting composition to provide a composition comprising about 5 wt. % to about 15 wt. % free fatty acids;
subsequent to FFA stripping, contacting the composition with a caustic solution to produce a first mixture;
separating from the first mixture a caustic-treated composition and producing an aqueous waste with a pH from about 2.0 to about 5.0;
combining the caustic-treated composition with silica particles to produce a slurry; and
removing the silica particles from the slurry to produce a treated composition;
wherein:
the composition comprises:
one or more of animal fats, animal oils, plant fats, plant oils, vegetable fats, vegetable oils, greases, and used cooking oil,
about 10 wppm or more of total metals;
about 8 wppm or more of phosphorus;
about 10 wppm or more of sulfur;
about 20 wppm or more of nitrogen; and
has an acid number from about 10 mg KOH/g to about 150 mg KOH/g;
the treated composition comprises:
a wt. % of free fatty acids about that of the composition; and
less total metals, phosphorus, sulfur, and nitrogen than the composition; and
the silica particles have an average particle size from about 10 microns to about 50 microns and a BET surface area from about 200 m 2 /g to about 1000 m 2 /g.
2 . The method of claim 1 , wherein the composition comprises about 5 wt. % to about 11 wt. % free fatty acids.
3 . The method of claim 1 , wherein the composition comprises about 5 wt. % to about 10 wt. % free fatty acids.
4 . The method of claim 1 , wherein the composition comprises 5 wt. % to about 10 wt. % free fatty acids; and the treated composition comprises:
less than 10 wppm of total metals;
less than 5 wppm of phosphorus;
less than 5 wppm of chlorine;
less than 5 wppm of sulfur;
less than 100 wppm of nitrogen; and
has an acid number from 10 mg KOH/g to about 20 mg KOH/g.
5 . The method of claim 1 , wherein the composition comprises yellow grease, brown grease, flotation grease, poultry fat, inedible corn oil, used cooking oil, inedible tallow, floatation tallow, palm sludge oil, or a mixture of any two or more thereof.
6 . The method of claim 1 , wherein the total metal comprise one or more members selected from the group consisting of As, Ca, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb, Sr, and Zn.
7 . The method of claim 1 , wherein the composition has an acid number from about 10 mg KOH/g to about 50 mg KOH/g.
8 . The method of claim 1 , wherein the method further comprises an alkalinity reduction step prior to contracting the composition with a caustic solution.
9 . The method of claim 1 , wherein the method further comprises an acid-degumming step prior to contracting the composition with a caustic solution.
10 . The method of claim 1 , wherein the method does not comprise contacting the composition with bleaching clays.
11 . The method of claim 1 , wherein the caustic solution may include an aqueous hydroxide solution, aqueous bicarbonate solution, aqueous bisulfide solution, aqueous alkoxide solution, a basic resin dissolved and/or suspended in an aqueous solution, methoxide solution, or combinations of two or more thereof.
12 . The method of claim 1 , wherein the silica particles are combined with the caustic-treated composition about 0.1% (w/w) to about 0.8% (w/w) based on weight of the silica particles to weight of the caustic-treated composition.
13 . The method of claim 1 , wherein the silica particles in aqueous dispersion at 15 wt. %. have a pH of about 2.0-6.0.
14 . The method of claim 1 , wherein the combining with silica particles is conducted at a temperature from about 150° F. to about 200° F., and the slurry is subjected to an absolute pressure from about 100 Torr to about 500 Torr.
15 . The method of claim 1 , wherein combining the silica particles may be conducted in a continuous flow operation tank.
16 . The method of claim 1 , wherein the method further comprises combining the slurry with diatomaceous earth (DE), wherein a weight ratio of DE to silica particles is about 0.1:1 to about 1.5:1.
17 . The method of claim 1 , wherein the slurry is filtered to remove the silica particles with one or more filters.
18 . The method of claim 17 , wherein the one or more filters may include pressure filtration, filter presses, cartridge filters, compression filters, membrane plate press, disc filters, drum filters, or a combination of any two or more thereof.
19 . The method of claim 18 , wherein the filters may be pre-coated with DE, cellulose, perlite, or any combination of any two or more thereof.
20 . The method of claim 1 , wherein the method further comprises hydroprocessing the treated composition.