1. Field of the Invention
The present invention relates to more efficient use of petroleum. More particularly, the present invention relates to a chemical composition of matter for the liquefaction and dissolution of paraffin waxes and asphaltenes into petroleum crude oil and distillate products at ambient temperatures.
The present invention relates generally to converting crystalline wax, as for example, exists in slop oil, crude oil and refined distillate products, into an amorphous form of wax, causing it to be dissolvable in for example, crude oil at ambient temperature and maintained in a dissolved state for a prolonged period of time at ambient temperature, and more particularly, in its preferred, exemplary embodiment, to the use preferably of a chemical composition of surfactants, leveling or plasticizing agents (plasticizers) and blends of fatty acids that can, for example, recover waste hydrocarbon products (paraffin waxes and asphaltenes) from both naturally occurring and synthetic sources, and more particularly to recover these waste hydrocarbon products for use as energy sources and to reduce environmental pollution. A number of other applications are also disclosed and claimed.
2. General Background of the Invention
Waxy materials present in crude oils and in the high boiling fractions of distillates are considered to be crystalline throughout but under certain conditions may behave like a colloid. Certain wax solutions of refined products such as petrolatum, when agitated or mixed for long periods near or at the crystallizing temperature, will form a completely transparent jelly. But the same solution, when chilled rapidly with moderate agitation will precipitate a wax that can be centrifuged.
It was observed many years ago in the sweating of solid paraffins at the petroleum refinery that three crystalline forms (manifestations) of wax are involved. These are known as “plate”, “malcrystal”, and “needle” (note, for example, The Chemistry and Technology of Waxes by Albin H. Warth, published by Reinhold Publishing Corp. (New York, 1947) p. 239). It was recognized that the relative proportion of these types of crystals not only has a relationship to the source of the crude but also to the process of handling the wax.
The members of each series crystallize similarly as either plates, malcrystals, or needles. If one type is present (plate, mal, or needle), the crystal form remains the same regardless of such factors as the amount and kind of solvent.
When crude oil is pumped from the ground and transported through pipelines, transported by ocean tankers, or stored in storage tanks on land or offshore, a large amount of heavy material separates and comes out of solution. The main component of this residue is high molecular weight (high melting point) paraffin waxes. In some cases the wax represents as much as 90 percent of the deposited residues.
The amounts of wax present in crude oil are to a large extent an indicator of its origin, whether the crude originated in Venezuela, Mexico, or Malaysia.
The mixture of wax, oil, sand, and water is referred to as “slop oil”, or “slop” (sludge), in the petroleum industry. The percentage of slop oil varies according to the type of crude and the conditions under which it has been transported. Usually the amount of slop oil ranges from a low of 0.5% to a high of 10%; normally, it is in the range of 2% to 5%.
For the last century and until today the only way to keep slop oil from separating from crude oil is to heat the slop oil while it is being transferred into mixing tanks with crude oil. The cost of keeping slop oil from separating from crude oil is a function of many variables such as temperature, solvent diluents (cutter stocks), and residence time of the crude in a tank or pipeline.
The petroleum industry is plagued with the problem of having to deliver crude oil to refineries in a timely and economic manner with a minimum amount of slop oil separation. If a pipeline becomes plugged up or clogged because of paraffin wax precipitating out during the pumping operation, a crisis can arise. Numerous pipelines worldwide are clogged daily or monthly due to wax precipitating out of the crude oil. Daily, 80,000,000 barrels of crude oil are pumped from the ground worldwide (as of May, 2004). If 5% of the heavy residues separated out of the crude oil being transported, whether by pipeline or tanker, the amount of slop oil or crude residue formed would be 4,000,000 barrels per day. This amounts to 1.5 billion barrels per year. If 70% of this slop oil is useable crude which can be processed to refine production, then the amount of recoverable hydrocarbon equals over 1.0 billion barrels per year. At a cost of $10.00/barrel for crude oil this amounts to the recovery of $10 billion per year of useable hydrocarbon as either energy or petrochemical feedstock.
In storage tanks the problems associated with wax settling out are tremendous and present an extremely challenging task for petroleum production companies, refiners and terminal operators.
When crude oil remains idle and cold in a storage tank, a heavy residue forms that, over time, accumulates at the bottom of the tank and reduces the tank's useable volume. This residue, known as slop oil (or slop, or sludge) consists of heavy paraffinic waxes and asphaltenes which solidify in crystalline form. Slop oil is extremely difficult to remove from tanks and presents a very costly disposal problem for the refinery and terminal operator.
Traditional tank cleaning methods use a combination of heat (e.g., 60 to 70 degrees C. or greater) and mechanical agitation to force the slop oil back into solution with crude oil, so the mixture can be pumped out of the tank. In order to keep the waxes and asphaltenes in solution in the crude oil, the mixture must be kept at high temperature, for example, 75 degrees C. or greater and, in most cases, continuously circulated. The tremendous amounts of energy required to heat and circulate large volumes of dense crude oil at these elevated temperatures over long periods of time increases handling costs dramatically.
After pumping out the slop oil containing paraffin waxes and asphaltenes, the slop oil mixture must be kept hot or the wax will separate from solution, and the problems associated with slop oil will recur. This need to use heat results in high energy costs and large losses.
For general background, “prior art” information pertinent to the invention, reference is made to (all incorporated herein by reference):
The Chemistry and Technology of Waxes by Albin H. Warth, published by Reinhold Publishing Corp. (New York, 1947), p. 239 et al;
Petroleum Refinery Engineering by W. L. Nelson, published by McGraw-Hill Book Co. (New York, 4th Ed. 1958), particularly Chapter 12 “DeWaxing” (pp 374-75 et seq.);
Physical Chemistry by Walter J. Moore, published by Prentice-Hall, Inc. (New York, 1955), particularly Chapter 16 “Surface Chemistry” (p. 498 et seq.); and chemical and process technology encyclopedia edited by Douglas M. Considine, published by McGraw-Hill Co. (New York, 1974), particularly its sub-section on “Waxes” (p. 1167 et seq.);
Composition and crystal form of the petroleum waxes, S. W. Ferris, H. C. Cowles, Jr., and L. M. Henderson (The Atlantic Refining Company) Industrial and Engineering Chemistry, June 1931, (pp 681 to 688); all references included in this article;
Crystal behavior of paraffin wax, S. W. Ferris and H. C. Cowles (The Atlantic Refining Company), Industrial and Engineering Chemistry, Nov., 1945 (pp 1054 to 1062); all references included in this article.
The following US Patent Documents are incorporated herein by reference: U.S. Pat. Nos. 6,783,582; 6,322,621; 3,554,913; Published US Patent Application Pub. No. US 2002/0066391 A1; and all references cited in these patent documents.