Chemistry: fischer-tropsch processes; or purification or recover – Liquid phase fischer-tropsch reaction
Reexamination Certificate
2001-10-18
2003-05-27
Parsa, J. (Department: 1621)
Chemistry: fischer-tropsch processes; or purification or recover
Liquid phase fischer-tropsch reaction
C044S301000, C210S764000, C435S249000
Reexamination Certificate
active
06569909
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to methods of inhibiting growth and reproduction of microorganisms in rapidly biodegradable hydrocarbonaceous products, containing minor amounts of aqueous liquids. The present invention also relates to rapidly biodegradable hydrocarbonaceous products containing an effective amount of a petroleum-derived hydrocarbonaceous product such that the rapidly biodegradable hydrocarbonaceous product resists visible growth of microorganisms.
BACKGROUND OF THE INVENTION
Certain microbiological problems may arise with respect to the storage and transportation of hydrocarbonaceous products. Hydrocarbons can act as a nutrient for microorganisms; therefore, hydrocarbonaceous products (i.e., fuels such as jet fuel, diesel fuel, naphtha; lubes, and solvents) can be attacked by microorganisms. Microorganisms can slowly grow at the boundary layers of the hydrocarbonaceous product and air, and can grow more rapidly if the hydrocarbonaceous product is also exposed to a layer of water.
Hydrocarbonaceous products are frequently exposed to a layer of water when stored in large storage vessels, such as storage tanks, fuel tanks of aircraft and holds of tankers. In these large storage vessels, water invariably forms due to condensation or it is initially present in the stored hydrocarbonaceous product and slowly separates therefrom. This water gradually forms a layer in the bottom of the storage vessels. The water layer forms an interface with the hydrocarbonaceous product, and becomes a breeding ground for a wide variety of microorganisms. These microorganisms utilize the hydrocarbonaceous product as a nutrient and can multiply.
Eventually the microorganisms can consume a large portion of the hydrocarbonaceous product. The extent to which the microorganisms consume the product is known as the extent of biodegradation, or the biodegradability of the product.
The microorganisms or microbes will grow mostly in the water phase, but when the hydrocarbonaceous product is disturbed during pumping or mixing, the microbes can be dispersed into the hydrocarbonaceous product and cause contamination. When present in the hydrocarbonaceous product, microbial growth can present a problem for several reasons. For example, hydrocarbonaceous products may become contaminated with microbes during storage or shipment and as a result of the microbes, become hazy or cloudy. The growing microorganisms may form sludge in the contaminated hydrocarbonaceous product. When contaminated hydrocarbonaceous products are used in an engine or equipment, the microbes and/or the sludge may decrease the efficiency of the engine or equipment or prevent it from functioning altogether, for example, by plugging filters. In addition, growth of microorganisms, in particular anaerobic sulfate reducing bacteria, in hydrocarbonaceous products during storage or transport may create corrosive sulfur-containing acids and damage the vessels in which the products are contained. This corrosion damage may lead to the need for eventual replacement of these large, expensive vessels.
Further, transport of hydrocarbonaceous products and/or a water layer contaminated with microbes creates a dispersal mechanism for human pathogens, waterborne diseases of plants and animals, and foreign organisms into the environment. For example, infectious bacteria such as cholera have been found in ballast water from marine tankers (“Global Spread of Microorganisms By Ships,”
Brief Communications
Nov. 2, 2000 issue of Nature). These infectious organisms can create both a human health problem, and a health problem to native species in the receiving country. Water can also be the vehicle for the introduction of foreign higher life forms into the receiving countries' environment. By this route, Zebra clams are believed to have been introduced into the San Francisco Bay region.
There is a need for hydrocarbonaceous products comprising rapidly biodegradable hydrocarbonaceous products that are capable of resisting visible growth of microorganisms and methods of inhibiting the growth and reproduction of microorganisms in rapidly biodegradable hydrocarbonaceous products, containing minor amounts of aqueous liquids.
SUMMARY OF THE INVENTION
The invention relates to hydrocarbonaceous products comprising rapidly biodegradable hydrocarbonaceous products that are capable of resisting visible growth of microorganisms. One aspect of the present invention is a hydrocarbonaceous product comprising: a) a rapidly biodegradable hydrocarbonaceous product; and b) an effective amount of a petroleum-derived hydrocarbonaceous product such that the resulting hydrocarbonaceous product resists visible growth of microorganisms for at least 10 days under ambient conditions when exposed to a certified inoculant. The rapidly biodegradable hydrocarbon product may include, for example, a Fischer-Tropsch derived liquid product or a low aromatics diesel fuel. When the rapidly biodegradable product is a Fischer-Tropsch derived liquid product, the Fischer-Tropsch product preferably may be one that has a branching index of less than five.
An additional aspect of the present invention is a method of inhibiting growth and reproduction of microorganisms in rapidly biodegradable hydrocarbonaceous products, containing minor amounts of aqueous liquids. The method comprises:
a) providing a rapidly biodegradable hydrocarbonaceous product;
b) adding an effective amount of a petroleum-derived hydrocarbonaceous product to resist visible growth of microorganisms for at least 10 days under ambient conditions when exposed to a certified inoculant; and
c) mixing the petroleum-derived hydrocarbonaceous product into the rapidly biodegradable hydrocarbonaceous product.
The method may also comprise the step of processing the mixture with hydrogen (i.e., hydrotreating, hydrocracking, and hydroisomerization) to remove sulfur and other impurities that originate from the conventional fuel component after the period in which growth is expected.
Definitions
Unless otherwise stated, the following terms used in the specification and claims have the meanings given below:
“Biocides” mean chemical compounds that kill or inhibit the growth of microorganisms, such as for example, bacteria, molds, slimes, fungi, and the like.
“Branching index” means a numerical index for measuring the average number of side chains attached to a main chain of a compound. For example, a compound that has a branching index of two means a compound having a straight chain main chain with an average of approximately two side chains attached thereto. The branching index of a product of the present invention may be determined as follows. The total number of carbon atoms per molecule is determined. A preferred method for making this determination is to estimate the total number of carbon atoms from the molecular weight. A preferred method for determining the molecular weight is Vapor Pressure Osmometry following ASTM D-2503, provided that the vapor pressure of the sample inside the Osmometer at 45° C. is less than the vapor pressure of toluene. For samples with vapor pressures greater than toluene, the molecular weight is preferably measured by benzene freezing point depression. Commercial instruments to measure molecular weight by freezing point depression are manufactured by Knauer. ASTM D-2889 may be used to determine vapor pressure. Alternatively, molecular weight may be determined from an ASTM D-2887 or ASTM D-86 distillation by correlations which compare the boiling points of known n-paraffin standards.
“Fischer-Tropsch derived liquid products mean hydrocarbonaceous, liquid products derived from a Fischer-Tropsch process. Fischer-Tropsch derived liquid products include, for example, Fischer-Tropsch naphtha, Fischer-Tropsch jet fuel, Fischer-Tropsch diesel fuel, Fischer-Tropsch solvent, Fischer-Tropsch lube base stock, Fischer-Tropsch lube base oil, Fischer-Tropsch lube base oil feedstock and mixtures thereof.
“Hydrocarbonaceous” means containing hydrogen and carbon atoms and potentially also containing he
Moir Michael E.
O'Rear Dennis J.
O'Reilly Kirk T.
Burns Doane Swecker & Mathis L.L.P.
Chervon U.S.A. Inc.
Parsa J.
LandOfFree
Inhibition of biological degradation in fischer-tropsch... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Inhibition of biological degradation in fischer-tropsch..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Inhibition of biological degradation in fischer-tropsch... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3071216