Abstract: A blend of aliphatic hydrocarbons and polyglycol ether(s) is used in a process for cleaning railroad tank cars that have been gravity drained of hydrocarbon fluids but may be left with a residuum containing heavy hydrocarbons, paraffin and noxious gas. A simple recirculation system is established between the chemical source, the contaminated railcar, canister filters and back to the chemical source. Contaminates are removed from the cleaning chemical by the filters and there is no water or steam used which might otherwise damage the railcar.

Abstract: Disclosed is a method and system for the efficient recycling of components involved in removing water insoluble contaminants from the surface of articles. A physically emulsified terpene-containing composition is applied to the surface of articles to effectively remove water insoluble contaminants. Following application, the physically emulsified composition quickly separates, releasing the contaminants and terpene from the water. The water, terpene and contaminants are separated for reuse in accordance with the present process. The physically emulsified composition includes between about 2 weight percent and about 40 weight percent of a terpene in water.

Abstract: A method is provided for cleaning parts soiled with oil components and seating terpenes from oil compositions using filters having suitable pore sizes to allow terpene components to pass through the walls of the filter as a permeate while not allowing oil components to pass therethrough. A separate aspect of the present invention utilizes a ceramic filter capable of separating water components from a mixture of terpenes and oil, thus allowing filtered water to be reused in a cleaning procedure. Using both types of filters in one operation provides a substantially closed loop recycling system where terpene components can be reused to clean additional articles, water can be reused to rinse such articles and contaminants removed in the cleaning process can be either reused or disposed of.