Process for removing color bodies from hydrocarbon-based fuels using activated carbon
A process for removing color bodies from hydrocarbon-based fuels, particularly gasoline, using an activated carbon is disclosed. Color bodies are removed from the fuel by contacting the fuel with such activated carbon having within this pore structure a fuel decolorizing amount of polymerized phosphoric acid or reduced transition metals. Phosphoric acid may be added to a non-phosphoric acid-activated carbon (such as steam activated coal-based) prior to the subsequent heat treatment or one can take advantage of residual phosphoric acid present in, for example, a phosphoric acid-activated wood-based carbon. Similarly, transition metals such as copper may be added to an activated carbon in a salt form in addition to whatever is already present therein as impurities.
1 . A process for removing color bodies from hydrocarbon-based fuel comprising the steps of:
a. contacting hydrocarbon-based fuel with a decolorizing carbon having within this pore structure a fuel decolorizing amount of polymerized phosphate; and
b. adsorbing at least a portion of color bodies within the hydrocarbon-based fuel onto the decolorizing carbon to produce a decolorized hydrocarbon-based fuel.
2 . The process of claim 1 wherein the decolorized hydrocarbon-based fuel of step (b) has a Saybolt gain of at least 15 compared to the hydrocarbon-based fuel of step (a).
3 . The process of claim 2 wherein the hydrocarbon-based fuel of step (a) has a Saybolt value less than or equal to −10 and the decolorized hydrocarbon-based fuel of step (b) has a Saybolt value of a least 12.
4 . The process of claim 1 wherein the decolorizing carbon comprises carbon produced by steam, phosphoric acid, or zinc chloride activation.
5 . The process of claim 1 wherein the fuel decolorizing amount of polymerized phosphate is in the range from about 1% to about 10%.
6 . The process of claim 5 wherein the fuel decolorizing amount of polymerized phosphate is in the range from about 2% to about 7.5%.