Processing Lipids
A method for converting lipids to alkyl esters may include receiving a reactant comprising one or more lipids. In some cases, the reactant may include substantial amounts of polar lipids and/or free fatty acids. Some reactants may be derived from photosynthetic organisms, such as algae and/or diatoms. The reactant may be mixed with an alcohol and a catalyst to form a mixture. The mixture may be heated, for example, to a temperature between 50 and 350 degrees Celsius, including between 80 and 220 degrees Celsius. Pressure may be controlled to be between 1 and 200 bar, including between 10 and 100 bar. At least a portion of the reactant may be converted to one or more alkyl esters. A biofuel may include alkyl esters made from lipids according to various methods.
1 . A method for converting lipids to alkyl esters, the method comprising:
receiving a reactant comprising one or more lipids;
mixing the reactant with an alcohol to form a mixture;
adding an acidic catalyst to the mixture;
heating the mixture to a temperature between 50 and 350 Celsius;
controlling a pressure above the heated mixture to be between 1 and 200 bar; and
converting at least a portion of the reactant to one or more alkyl esters.
2 . The method of claim 1 , wherein the reactant includes more than 2% of one or more free fatty acids or polar lipids.
3 . The method of claim 2 , wherein the reactant includes more than 10% of one or more free fatty acids or polar lipids.
4 . The method of claim 1 , wherein the reactant includes less than 30% of one or more triglycerides.
5 . The method of claim 1 , wherein the reactant includes between 10% and 90% of one or more triglycerides.
6 . The method of claim 1 , wherein the lipids have been synthesized by one or more algae.
7 . The method of claim 6 , wherein the algae include a member of the genus Nannochloropsis.
8 . The method of claim 1 , wherein the alcohol includes methanol, and the alkyl esters include a methyl ester.
9 . The method of claim 1 , wherein the alcohol includes any of ethanol, a butanol, and a propanol.
10 . The method of claim 1 , wherein a ratio of the alcohol to the reactant is less than 1000:1.
11 . The method of claim 10 , wherein the ratio is less than 10:1.
12 . The method of claim 10 , wherein the ratio is less than 3:1.
13 . The method of claim 10 , wherein the ratio is greater than 1:1.
14 . The method of claim 1 , wherein the acidic catalyst includes a heterogeneous catalyst.
15 . The method of claim 1 , wherein the acidic catalyst includes a homogeneous catalyst.
16 . The method of claim 1 , wherein the acidic catalyst includes a sulfonated catalyst.
17 . The method of claim 1 , wherein the acidic catalyst includes sulfuric acid.
18 . The method of claim 1 , wherein the acidic catalyst includes aqueous carbonic acid.
19 . The method of claim 18 , wherein the carbonic acid results from a dissolution of carbon dioxide in a liquid.
20 . The method of claim 19 , wherein the carbon dioxide results from combustion of fuel.
21 . The method of claim 1 , wherein a ratio of the acidic catalyst to the alcohol is between 0.1 and 100%.
22 . The method of claim 21 , wherein the ratio is between 1 and 5%.
23 . The method of claim 1 , wherein the temperature is between 80 and 220 Celsius.
24 . The method of claim 1 , wherein the pressure is between 10 and 100 bar.
25 . A method for converting lipids to alkyl esters, the method comprising:
receiving a reactant comprising:
between 2 and 96% triglycerides,
between 2 and 96% free fatty acids, and
between 2 and 80% polar lipids;
mixing the reactant with an alcohol to form a mixture;
adding an acidic catalyst to the mixture;
heating the mixture to a temperature between 100 and 200 Celsius;
controlling a pressure above the heated mixture to be between 10 and 100 bar; and
converting at least a portion of the reactant to one or more alkyl esters.
26 . The method of claim 25 , further comprising extracting at least a portion of the alkyl esters with a nonpolar solvent.
27 . A biofuel comprising esters made according to a method comprising:
receiving a reactant comprising free fatty acids and triglycerides;
mixing the reactant with an alcohol to form a mixture;
adding an acidic catalyst to the mixture;
heating the mixture to a temperature between 50 and 350 Celsius;
controlling a pressure above the heated mixture to be between 1 and 200 bar; and
converting at least a portion of the reactant to alkyl esters;
the biofuel having an ester profile indicative of the free fatty acids and the triglycerides.
28 . The biofuel of claim 27 , wherein at least a portion of the ester profile is indicative of a reactant comprising free fatty acids associated with any of a grease, tallow, lard, used vegetable oil, and rendered poultry fat.
29 . A biofuel comprising a plurality of esters made according to a method comprising:
receiving a reactant comprising lipids from one or more algae;
mixing the reactant with an alcohol to form a mixture;
adding an acidic catalyst to the mixture;
heating the mixture to a temperature between 50 and 350 Celsius;
controlling a pressure above the heated mixture to be between 1 and 200 bar; and
converting at least a portion of the reactant to one or more alkyl esters;
the biofuel including an ester profile indicative a lipid profile associated with the lipids from the one or more algae.
30 . The biofuel of claim 29 , wherein the algae include any of the genus Nannochloropsis.
31 . The biofuel of claim 29 , wherein at least a portion of the ester profile is indicative one or more polar lipids.
32 . A reactor for converting lipids to esters, the reactor comprising:
one or more inlets to receive any of a reactant, and alcohol, and an acidic catalyst into a sealed volume;
mixing means to mix the reactant, alcohol, and catalyst; and
a heater to heat the mixture.
33 . The reactor of claim 32 , further comprising a pressure control apparatus configured to monitor a pressure inside the volume.
34 . The reactor of claim 33 , wherein the pressure control apparatus adjusts the pressure in response to the monitored pressure.