Abstract

EARTH (Canada) Corporation is proud to launch its latest revolutionary developments in oil/water separation at the Global Petroleum Show. TORR ™ (Total Oil Remediation and Recovery) removes free-floating and emulsified oils in water without the need for heat or chemicals. No waste is created from this technology. Treated water can reach non-detectable hydrocarbon concentrations. The introduction of TORR ™ is a significant breakthrough for water treatment solutions with SAGD, production water treatment, environmental remediation and any other applications where oily water is a concern.

Introduction

Oil and grease are present at numerous commercial, industrial and government sites. The presence of oil poses a severe challenge for oily water remediation technologies. Oil and grease must generally be removed from wastewater since those materials can foul instruments and equipment, interfere with other processes and may accumulate in unwanted areas causing a hazard or performance problem. Furthermore, oil and grease are very damaging to the environment and could cause a significant pollution problem.

Oily wastewaters are produced in petroleum production, refining and storage petrochemical complexes, steel and metal industries, textile and food industries. Oil spills and contaminated groundwaters are also big generators of oily waters. The resulting effluents vary widely in volume and in oil content and thus, the treatment requirements must be based on the oily water's unique characteristics and its ultimate end use.

BASIC SEPARATION THEORY

The removal of oil and grease from wastewaters can be accomplished by the use of several well-known and widely accepted techniques. However, the performance of any given separation technique will depend entirely on the condition of the oil-water mixture. Present techniques for the separation of oil from water are based on their difference of density. Stoke's Law states that rising velocity (Vr) is a function of the square of the oil droplets' diameter.

Vr = g d2 (ρw - ρo) / 18 η Where: Vr = rise velocity of oil droplet g = acceleration due to gravity ρw = density of water ρo = density of oil d = oil particle diameterη ?= viscosity of water From Stoke's Law, it can be seen that droplet size has the largest impact on rising velocity rate. Consequently, the bigger the droplet size, the less time it takes for the droplet to rise to a collection surface and thus the easier it is to treat the water. The oil in the wastewater can be present as free-oil, and/or emulsified, and/or dissolved states in different proportions. This oil droplet size distribution is one of the most important factors affecting the design of oil-water separators.

Free-oil is defined as an oil droplet of 150 microns, which will float immediately to the surface due to its large size and high rise velocity. Emulsion is oil which is dispersed in the water in a stable fashion due to its small diameter and thus to its low rise velocity.

Emulsions can be found on two types: mechanical emulsions and chemical emulsions. Mechanical emulsions are created through the process of pumping, large pressure drops through chokes, control valves, and otherwise mixing the oil-water solution.

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