Desalter effluent

Reroute Desalter Effluent Hot desalter effluent water currently flows into the process water drainage system at Combination unit. This project would install a new line and route this stream directly to the API Separator. This reduces volatile losses from the sewer system by reducing process sewer temperature and oil content. Volatile losses at the API Separator increase slightly. 

Aqueous desalter effluent contains sediments, oil, dissolved salts, and sulfides. It is treated initially by using an American Petroleum Institute (API) separator for residual oil removal and recovery (Fig. 18.9). Any oil droplets larger than about 150 p.m (0.15 mm) in diameter are collected as an oil phase, which is routed to the refinery slop oil stream to join any other off-specification liquid oil streams for reprocessing. Inclined plastic plates inserted into an oil-water separator of this type substantially increase the speed and... 

Procedures for hydrogen sulfide (and ammonia) removal can be similar to those used for desalter effluent [69], and have been described in detail [73]. 

If HjS is continuously present in the flare gas or if the flare seal drum also functions as a sour water disengaging drum, then the effluent seal water must be routed to a sour water stripper, desalter, or other safe means of disposal. Withdrawal from the drum is by pump in place of the normal loop seal arrangement. Two pumps are provided one motor driven for normal use, and the other having a steam turbine drive with low pressure cut-in. The seal drum level is controlled by LIC with high and low alarm lights plus an independent high level alarm. 

Steven Carr (SmithKline Beecham) has used microbore columns to desalt proteins prior to ES-MS (32). The pore diameter of PolyHEA used (usually 200 A) was selected so that all proteins of interest would elute at Vo with 50 mM formic acid. Only the Vo peak was allowed to flow into the ES-MS nebularizer the rest of the SEC effluent (including the salts) was diverted to waste by opening a microdumper valve between the column and the nebularizer. The properties of the mobile phase were quite compatible with ES-MS analysis. 

A similar ion-exchange resin method was used by Ling in 1955 (LI) for the examination of combined amino acids in urine. According to this procedure urine was desalted and simultaneously freed from amino acids by using Amberlite IR-112, H+-form resin. The effluent collected from the column was then fractionated on Amberlite IRA, OH--form resin, by successive elution with 0.16 N acetic acid, 0.08 N formic acid, 0.25 N formic acid, 0.08 N hydrochloric acid, and finally with 0.16 N formic acid. The solutions of all acids contained 10% of acetone. The collected fractions were hydrolyzed with hydrochloric acid and the liberated amino acids identified by means of paper chromatography. 

Conventional chemical treatment of metal finishing wastes will usually produce clarified effluent acceptable for discharge however, in those applications where it is desirable or necessary to recover the clarified rinse water for re-use, the technologies are utilized to purify or "desalt" the effluent for re-use. 

Solutions to example cases A and B, when two stage desalting and recycle is applied, are 8.95 barrels and 49.6 barrels of dilution water required, respectively. For the 50,000 barrels of net oil in case A, this is 50 x 8.95 = 448 bwpd, and for case B, 50 x 49.6 = 2,480 bwpd dilution water. Note that the 0.2% BS W in case B requires more than 5 times the dilution water as does case A, with only 0.1% BS W effluent. 

For any mode of disposal, effluent water from the desalting plants In one area will be collected at a central place for treatment before disposal. Ir. the treatment process, the effluent will be filtered, treated for corrosion and scale Inhibition, bacterial fouling and dcoxygenated. Otner gases like H S and COg if ar.y will also be rcaoved to tbe desired... 

The emulsion enters the desalter vessel where a high-voltage electrostatic field is applied. The electrostatic field causes the dispersed water droplets to coalesce, agglomerate, and settle to the lower portion of the vessel. The various contaminants from the crude oil concentrate in the water phase. The salts, minerals, and other water-soluble impurities are discharged from the settler to the effluent system. Clean, desalted hydrocarbon product flows from the top of the settler and is ready for the next processing step. 

A typical flow diagram of a two-stage crude oil distillation system is shown in Fig. 18.14. The crude oil is preheated with hot products from the system and desalted before entering the fired heater. The typical feed to the crude-fired heater has an inlet temperature of 550°F, whereas the outlet temperature may reach 657-725°F. Heater effluent enters the crude distillation (CD) column, where light naphtha is drawn off the overhead tower. Heavy naphtha, kerosene, diesel, and cracking streams are sidestream drawoffs from the distillation column. External reflux for the tower is provided by several pumparound streams.12... 

Hie residue was redissolved in double-distilled water and desalted on Dowex 50W-X8 (100-200 mesh) resin that had been cleaned with NaOH and protonated with double-distilled HC1 (13). Amino acids were eluted from the colunn with 1.5 M NH4OH prepared by bubbling NHj through double distilled water. The effluent was again evaporated to dryness. 

Electrodialysis. In electrodialysis, separation of an aqueous stream is achieved through the use of synthetic membranes and an electric field. The membrane allows only one type of ions to pass through and may be chosen to remove other ions that move in the opposite direction. Therefore, it produces one stream rich in particular ions and another stream depleted of those ions. The two streams can be recycled or disposed off. This technique is commonly used in the desalination of brackish water. The other uses are in acid mine drainage treatment, the desalting of sewage-plant effluents, and in sulfite-liquor recovery. 

PLA2 was modified with PG according to the procedure described by Takahashi (1968). One micromole of PLA2 in 1 ml of 0.1 M sodium borate buffer (pH 9.0) was incubated with 100-fold molar excess of PG. The reaction was allowed to proceed for 2 hr at 37°C, then quenched by the addition of a few drops of acetic acid. The modified proteins were immediately desalted by passing through a Sephadex G-25 column equilibrated with 0.1 M acetic acid and the protein fraction was lyophilized. The modified proteins were separated by HPLC on a SynChropak RP-18 column (4.6 mm x 25 cm), equilibrated with 0.1% TFA and eluted with a linear gradient of 28-35% acetonitrile for 35 min. Flow rate was 0.8 ml/min and the effluent was monitored at 280 nm. 

Desalting can be achieved by precipitation with ethanolic atmnonium acetate [4], solid-phase extraction (SPE), microdialysis [13], Fe " -loaded immobilized metal affinity chromatography (IMAC) [14], cation-exchange coluttms (SCX) [15-16], or combinations thereof [17-18]. The SCX procedure can be applied on-hne with direct infusion of the effluent into ESl-MS [15-16]. The mobile phase applied is similar to the one applied in LC-MS, i.e., 50% acetonitrile in 10 mmol/1 aqueous TEA. 

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