Produced water treatment coalescers

Improved Disposal Water Treatment at Bahrain Oil Fields" by Mum el at. discusses solutions to environmental concerns at Awali field. As Awali field water cuts increased, the amount of produced water and oil carry-over increased. To avoid environmental damage, more efficient oil-removal equipment was necessary. A wide variety of equipment was evaluated and the vertical-tube coalescer was selected. A description of the unit is presented. Performance evaluations were conducted, and the units exhibited good oil-removal efficiencies... 

Raw lac is first treated to remove water-soluble carbohydrates and the dye that gives lac its red color. Also removed are woody materials, insect bodies, and trash. It is further refined by either hot filtration or a solvent process. In the heat process, the dried, refined lac is filtered molten through cloth or wine screens to produce the standard grades of orange shellac. In the solvent process, lac is dissolved and refluxed in alcohol solvents, filtered to remove dirt and impurities, and concentrated by evaporation. The lac can be further decolori2ed in this process to produce very pale grades. Bleached shellac is prepared by treatment with dilute sodium hypochlorite and coalesced into slabs. 

Some emulsions are undesirable when they occur. In process industries chemical demulsification is commonly used to separate water from oil in order to produce a fluid suitable for further processing. The specific kind of emulsion treatment required can be highly variable, even within the same industry. The first step in systematic emulsion breaking is to characterize the emulsion in terms of its nature (O/W, W/O, or multiple emulsion), the number and nature of immiscible phases, the presence of a protective interfacial film around the droplets, and the sensitivity of the emulsifiers [295,408,451], Demulsification then involves two steps. First, there must be agglomeration or coagulation of droplets. Then, the agglomerated droplets must coalesce. Only after these two steps can complete phase separation occur. It should be realized that either step can be rate determining for the demulsification process. 

Trucking is a more economic and expedient method of transporting produced emulsions to production treatment facilities, particularly for heavy crude oils that are difficult to pump. However, over extended distances (i.e., traveling time in excess of 1 h), free-water settling can be quite pronounced within a tanker truck. Agitation due to travel over rough roads may also promote some degree of coalescence. 

---