Salinity recovery

Including a surfactant in the caustic formulation (surfactant-enhanced alkaline flooding) can increase optimal salinity of a saline alkaline formulation. This can reduce iaterfacial tension and increase oil recovery (255,257,258). Encouraging field test results have been reported (259). Both nonionic and anionic surfactants have been evaluated in this appHcation (260,261). 

The generated water vapor rises through a screen (demister) placed to remove entrained saline water droplets. Rising further, it then condenses on the condenser tube bank, and internal heat recovery is achieved by transferring its heat of condensation to the seawater feed that is thus being preheated. This internal heat recovery is another of the primary advantages of the MSF process. The energy performance of distillation plants is often evaluated by the performance ratio, PR, typically defined as... 

The pressure to be used for reverse osmosis depends on the salinity of the feedwater, the type of membrane, and the desired product purity. It ranges from about 1.5 MPa for low feed concentrations or high flux membranes, through 2.5—4 MPa for brackish waters, and to 6—8.4 MPa for seawater desalination. In desalination of brackish or sea water, typical product water fluxes through spiral-wound membranes are about 600—800 kg/m /d at a recovery ratio RR of 15% and an average salt rejection of 99.5%, where... 

Acrylamide—polymer/Ct(III)catboxylate gel technology has been developed and field tested in Wyoming s Big Horn Basin (211,212). These gels economically enhance oil recovery from wells that suffer fracture conformance problems. The Cr(III) gel technology was successful in both sandstone and carbonate formations, and was insensitive to H2S, high saline, and hard waters (212). 

Electrodialysis is a particularly economic process for low-salinity waters when compared to RO because, although the initial capital cost may be 10 to 15% higher, it generally requires no pretreatment, it produces a higher recovery rate (around 80-85%), it has a lower operating and maintenance cost, and the membranes last twice as long (up to 10 years). 

Adsorption and retention studies of surfactants to sand in high-salinity reservoirs showed no differences between nonionics and ether carboxylates [185— 187] low retention and a positive behavior for good oil recovery has been found. 

A RO stage can be used to reduce salinity and related parameters for high standard industrial reuse using the former UF effluent as feed stream. A pilot plant with 0.4 m h constant permeate flux capacity has been used in this demonstration. Table 7 summarizes the main technical characteristics of this plant. In order to increase the overall system recovery ratio while maintaining an acceptable... 

G. Ma. Laboratory study on polymer flooding in oil reservoir with high salinity. Oil Gas Recovery Technol, 3(2) I,1, 33,1996. 

Enzyme-linked immunosorbent assay (ELISA). Li and Li developed an ELISA procedure for imidacloprid to determine its residues in coffee cherry and bean extracts. A 25-g amount of sample extracted with 300 mL of methanol and 1% sulfuric acid (3 1, v/v) for 3 min. An aliquot of the sample extract (0.5 mL) is mixed with 1 mL of water and a gentle stream of nitrogen is used to evaporate methanol. The solution is then extracted with 1 mL of ethyl acetate, the extract is reconstituted in 1 mL of PBST (phosphate-buffered saline containing 0.05% Tween 20) and competitive ELISA is performed to quantify imidacloprid in the extract. Eor methanol extracts of coffee cherries and beans fortified with imidacloprid at 0.5 mgL recoveries of imidacloprid by the ELISA method were 108 and 94, respectively. 

The usefulness of xanthan in polymer flooding for enhanced oil recovery is based on its ability to yield large increase in viscosity at low polymer concentrations under high-temperature and high salinity conditions. This important property of xanthan is determined both by its molecular weight and by the conformation adopted in solution (1). 

Increasing the water-wet surface area of a petroleum reservoir is one mechanism by which alkaline floods recover incremental oil(19). Under basic pH conditions, organic acids in acidic crudes produce natural surfactants which can alter the wettability of pore surfaces. Recovery of incremental oil by alkaline flooding is dependent on the pH and salinity of the brine (20), the acidity of the crude and the wettability of the porous medium(1,19,21,22). Thus, alkaline flooding is an oil and reservoir specific recovery process which can not be used in all reservoirs. The usefulness of alkaline flooding is also limited by the large volumes of caustic required to satisfy rock reactions(23). 

Kumar A., Noh M., et al. Reservoir simulation of C02 storage in deep saline aquifers. 2004 SPE/DOE Fourteenth Symposium on Improved Oil Recovery, Tulsa, USA(89343). 

A procedure for immobilization of a P. stutzeri UP-1 strain using sodium alginate was reported [133], This strain does not perform sulfur-specific desulfurization, but degrades DBT via the Kodama pathway. Nevertheless, the report discussed immobilization of the biocatalyst cells in alginate beads with successful biocatalyst recovery and regeneration for a period of 600 h. However, the immobilized biocatalyst did decrease in specific activity, although the extent of loss was not discussed. The biocatalyst was separated after every 100 h of treatment, washed with saline and a boric acid solution and reused in subsequent experiment. The non-immobilized cells were shown to loose activity gradually with complete loss of activity after four repeat runs of 20 hour each. The report does not mention any control runs, which leaves the question of DBT disappearance via adsorption on immobilized beads unanswered and likewise the claim of a better immobilized biocatalyst. 

The long-term goal of this investigation is an understanding of the effect of a particular mode of adsorption on montmorillonite which ensures that under pressure the clay platelets align parallel to a solid surface even under saline conditions. This is an important phenomenon in petroleum recovery processes. 

The recovery of selenium was satisfactory. The forms of selenium in waters are known to be selenite and selenate [7]. Selenium occurs in non-saline water at concentrations ranging from less than 0.0002 xg/l to greater than 50 xg/l. Therefore, a large sample size is necessary for analysis at lower concentration levels. 

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