Fuel and related compositions – Liquid fuels
Reexamination Certificate
2001-10-18
2004-10-05
Toomer, Cephia D. (Department: 1714)
Fuel and related compositions
Liquid fuels
C044S412000, C044S434000, C044S437000, C044S451000, C585S014000, C518S700000, C518S711000
Reexamination Certificate
active
06800101
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the use of deactivatable biocides for hydrocarbonaceous products, in particular, rapidly biodegradable hydrocarbonaceous products. The present invention also relates to methods of inhibiting growth and reproduction of microorganisms in hydrocarbonaceous products, in particular, in rapidly biodegradable hydrocarbonaceous products, containing minor amounts of aqueous liquids.
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 appropriate biocides for rapidly biodegradable hydrocarbonaceous products and methods of inhibiting the growth and reproduction of microorganisms in rapidly biodegradable hydrocarbonaceous products containing minor amounts of aqueous liquids. There is also a need for biocides for all hydrocarbonaceous products and methods of inhibiting growth and reproduction of microorganisms in hydrocarbonaceous products in which the biocide can be deactivated or neutralized after the period in which biological growth is expected to minimize potential environmental damage.
SUMMARY OF THE INVENTION
The invention relates to the use of deactivatable biocides for hydrocarbonaceous products, in particular, rapidly biodegradable hydrocarbonaceous products. These deactivatable biocides can be deactivated or neutralized after the period in which biological growth is expected to minimize potential environmental damage.
One aspect of the present invention is a biologically inhibited hydrocarbonaceous product comprising: a) a hydrocarbonaceous product subject to biological growth; and b) an effective amount of a deactivatable biocide to resist visible growth of microorganisms for at least 10 days under ambient conditions when exposed to a certified inoculant. The deactivatable biocide is deactivated or neutralized after the period in which biological growth is expected. Deactivation of the biocide minimizes environmental damage when the product, or streams that come in contact with the product, are introduced into the environment. The deactivatable biocide is irreversibly deactivated, i.e. the deactivable biocide does not re-generate to become active upon release to the environment.
The hydrocarbonaceous product may be a rapidly biodegradable hydrocarbonaceous product. The rapidly biodegradable hydrocarbonaceous product may be, for example, a Fischer-Tropsch-derived liquid product; a product derived from petroleum, diesel fuel, solvent, jet fuel, naphtha, lube base stock, lube base stock feedstock, or synthetic crude; or mixtures thereof. Preferably the product is a Fischer-Tropsch-derived liquid product. When the product is a Fischer-Tropsch-derived liquid product, the Fischer-Tropsch product preferably has a branching index of less than five.
An additional aspect of the present invention is a method of inhibiting the growth and reproduction of microorganisms in hydrocarbonaceous products containing minor amounts of aqueous liquids. In this method a hydrocarbonaceous product is provided. To the hydrocarbonaceous product is added an effective amount of a deactivatable biocide to resist visible growth of microorganisms for at least 10 days under ambient conditions when exposed to a certified inoculant. After the period in which growth and reproduction of microorganisms is expected, an effective amount of a neutralizing agent is added to deactivate the biocide. Deactivation of the biocide minimizes environmental damage when the product, or streams that come in contact with the product, are introduced into the environment. The biocide may be deactivated before the hydrocarbonaceous product and aqueous phase have been separated or after the hydrocarbonaceous product and aqueous layer have been separated. The deactivatable biocide is irreversibly deactivated, i.e. the deactivable biocide does not re-generate to become active upon release to the environment.
The hydrocarbonaceous product may be a rapidly biodegradable hydrocarbonaceous product. The rapidly biodegradable hydrocarbonaceous product may be, for example, a Fischer-Tropsch-derived liquid product; a product derived from petroleum, diesel fuel, solvent, jet fuel, naphtha, lube base stock, lube base stock feedstock, or synthetic crude; or mixtures thereof. Preferably the product is a Fischer-Tropsch-derived liquid product. When the product is a Fischer-Tropsch-derived liquid product, the Fischer-Tropsch product preferably has a branching index of less than five. When the product is a Fischer-Tropsch-derived liquid product, the deactivatable biocide is preferably a Fischer-Tropsch-derived deactivatable biocide.
A further aspect of the present invention is a method of inhibiting the growth and reproduction of microorganisms in Fischer-Tropsch-derived liqui
Moir Michael E.
O'Rear Dennis J.
O'Reilly Kirk T.
Burns Doane Swecker & Mathis L.L.P.
Chevron U.S.A. Inc.
Toomer Cephia D.
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