A method is provided for reprocessing a petroleum-based waste oil feedstock into diesel fuel. The method includes forming a treated feedstock by (a) filtering the feedstock, thereby removing solids and metals from the feedstock, and (b) dehydrating the feedstock; vaporizing the treated feedstock to produce an oil vapor; passing the oil vapor through at least one catalyst bed and subsequently through a cooler, thereby converting the oil vapor to a hydrocarbon liquid product with a diesel product boiling point range; and removing contaminants from the hydrocarbon liquid product, wherein the contaminants are selected from the group consisting of particulates and color precursors.

Provided herein are systems and methods for removing halogens and sulfur from used oil. The used oil is heated and aerated, followed by rapid vaporization and cooling. The cooled oil is then subjected to an electrical field before being filtered.

A double-field coupling dehydrator and an optimization method for parameters. Parameters to be optimized is determined. Simulations to the double-field coupling dehydrator is carried out according to the parameters to be optimized, individually. Optimal ranges of the parameters to be optimized are determined according to simulation results. Optimized parameter combinations of the parameters to be optimized are determined separately. Separation efficiencies of the double-field coupling dehydrator under different optimized parameter combinations are obtained to determine an optimal parameter combination. The method considers both influences of single parameters and interactions between the parameters on the separation efficiency. Based on numerical simulation results of the double-field coupling dehydrator, these influences are analyzed by a software Design-Expert to obtain an optimal parameter combination.

A double-field coupling dehydrator and an optimization method for parameters. Parameters to be optimized is determined. Simulations to the double-field coupling dehydrator is carried out according to the parameters to be optimized, individually. Optimal ranges of the parameters to be optimized are determined according to simulation results. Optimized parameter combinations of the parameters to be optimized are determined separately. Separation efficiencies of the double-field coupling dehydrator under different optimized parameter combinations are obtained to determine an optimal parameter combination. The method considers both influences of single parameters and interactions between the parameters on the separation efficiency. Based on numerical simulation results of the double-field coupling dehydrator, these influences are analyzed by a software Design-Expert to obtain an optimal parameter combination.

A method is provided for reprocessing a petroleum-based waste oil feedstock into diesel fuel. The method includes forming a treated feedstock by (a) filtering the feedstock, thereby removing solids and metals from the feedstock, and (b) dehydrating the feedstock; vaporizing the treated feedstock to produce an oil vapor; passing the oil vapor through at least one catalyst bed and subsequently through a cooler, thereby converting the oil vapor to a hydrocarbon liquid product with a diesel product boiling point range; and removing contaminants from the hydrocarbon liquid product, wherein the contaminants are selected from the group consisting of particulates and color precursors.

A method of treating cooling circuit water of industrial plants (2) contaminated with organic substances and inorganic particles, comprises the following steps: a) separating the organic substances and inorganic particles from the cooling circuit water to obtain precleaned cooling circuit water; b) cooling the precleaned cooling circuit water by an open cooling tower (11) to obtain cooled precleaned cooling circuit water; c) desalinating at least a partial volume flow of the cooled precleaned cooling circuit water by an desalination plant (14) to obtain cleaned cooling circuit water; and d) adding bacteria capable of degrading organic substances present in the cooling circuit water. The bacteria are added to the cooling circuit water before the separation in accordance with step a), before the cooling in accordance with step b) and/or before the desalination in accordance with step c), to form a biological cleaning stage.

Methods are provided for in-situ detection of varnish and/or deposit precursors in a lubricant in a lubricating environment. An electrostatic accumulator can be used within a lubricating environment to enhance accumulation of varnish and/or deposit precursors on portions of the electrostatic accumulator. The deposits accumulated on the electrostatic accumulator can then be characterized in-situ. The potential difference across portions of the electrostatic accumulator can cause an enhanced rate of deposit accumulation on the electrostatic accumulator, which can facilitate characterization of the tendency of a lubricant to accumulate deposits in the lubricating environment.

The invention discloses a double-field coupling dehydrator and an optimization method for parameters thereof. The optimization method includes: determining parameters to be optimized; carrying out simulations to the double-field coupling dehydrator according to the parameters to be optimized, separately; determining optimal ranges of the parameters to be optimized according to simulation results; determining optimized parameter combinations of the parameters to be optimized, separately; carrying out simulations to the double-field coupling dehydrator according to the optimized parameter combinations, separately; obtaining separation efficiencies of the double-field coupling dehydrator under different optimized parameter combinations; and determining an optimal parameter combination according to the separation efficiencies of the double-field coupling dehydrator. The method considers both influences of single parameters and interactions between the parameters on the separation efficiency. Based on numerical simulation results of the double-field coupling dehydrator, these influences are analyzed by a software Design-Expert to obtain an optimal parameter combination.

A fuel and/or lubricant system for an engine can include an engine component configured to be in fluid communication with the fuel and/or lubricant, and an alternating current (AC) source electrically connected to the engine component to create an electric field of alternating polarity to subject particles within the fuel and/or lubricant to dielectrophoresis as the fuel and/or lubricant passes through the electric field to prevent deposits from forming on the engine component. In certain embodiments, the engine component can be a filter screen configured to filter the fuel and/or lubricant to subject particles within the fuel and/or lubricant to dielectrophoresis as the fuel and/or lubricant passes through the filter screen.

Methods are provided for in-situ detection of varnish and/or deposit precursors in a lubricant in a lubricating environment. An electrostatic accumulator can be used within a lubricating environment to enhance accumulation of varnish and/or deposit precursors on portions of the electrostatic accumulator. The deposits accumulated on the electrostatic accumulator can then be characterized in-situ. The potential difference across portions of the electrostatic accumulator can cause an enhanced rate of deposit accumulation on the electrostatic accumulator, which can facilitate characterization of the tendency of a lubricant to accumulate deposits in the lubricating environment.