Brine streams

Older methods of stripping used with concentrations below 1000 ppm utilize a stream of air flowing countercurrent to the brine stream. The bromine is then recovered from the air with wet scrap iron, ammonia, sodium carbonate, or sulfur dioxide (23—25). 

Process Flow The schematic in Fig. 22-56 may imply that the feed rates to the concentrate and diluate compartments are equal. If they are, and the diluate is essentially desalted, the concentrate would leave the process with twice the salt concentration of the feed. A higher ratio is usually desired, so the flow rates of feed for concentrate and feed for diluate can be independently controlled. Since sharply differing flow rates lead to pressure imbalances within the stack, the usual procedure is to recirculate the brine stream using a feed-and-bleed technique This is usually true for ED reversal plants. Some nonreversal plants use slow flow on the brine side avoiding the recirculating pumps.. Diluate production rates are often 10X brine-production rates. 

Some radioactive bromine (half-life 36 hours), in the form of ammonium bromide, was put into a brine stream as a radioactive tracer. At another plant 30 km away, the brine stream was electrolyzed to produce chlorine. Radioactive bromine entered the chlorine stream and subsequently concentrated in the base of a distillation column, which removed heavy ends. This column was fitted with a radioactive-level controller. The radioactive bromine affected the level controller, which registered a low level and closed the bottom valve on the column. The column became flooded. There was no injury, but production was interrupted. 

The plcint shown in Figure 1 consists of a water pretreatment plant and four sepairate blocks of "Permasep" units. All blocks cire fed by the Scime high pressure pump, cuid each block consists of 4-inch modules, reject-staged in a 2 to 1 ratio. The total conversion is about 70 percent — this means that cibout 70 percent of the feed water is converted to product, with 30 percent discarded as a brine stream. 

Biological fouling was monitored using the customary indicators of RO performance, including flux (productivity), salt passage, and bundle pressure drops (AP). In addition, the total bacteria count (TBC) of the RO feed water and the reject brine stream were also obtained using the membrane filtration method (Ref. 6). The increase in TBC between the feed and reject portions of the system had been found in the preliminary stages of... 

The osmotic pressure of brackish water is approximately 11 psi per 1000 ppm salt, so osmotic pressure effects do not generally limit water recovery significantly. Limitations are generally due to scaling. Typical water recoveries are in the 70-90 % range, which means the brine stream leaving the system is up to 10 times more concentrated in calcium, sulfate and silica ions present in the feed. If scaling occurs, the last modules in the system must be replaced first. 

An integrated membrane desalination system based on NF, RO, and MD has been proposed [11]. In this system a NF unit has been used as pretreatment, while the M D contributed to concentrate the two brine streams from both NFand RO (Figure 12.2). 

Electrolyzer mercury losses occur in the spent brine in the form of finely divided mercury droplets, as dissolved mercuric chloride, and as the stable tetrachloromercury complex (HgCl ). Droplet entrainment in the brine stream occurs both directly, from the use of a high-speed centrifugal pump to return mercury from the decomposer to the upper end of the electrolyzer. 

The components of most refinery liquid waste streams are recovered and reused, whenever feasible. Unfortunately, some of these, such as aqueous caustic phenolic or caustic sulfidic wastes, do not lend themselves readily to reuse. Deep well disposal, incineration, or precipitation in some manner and landfilling of the separated solids are the measures used in these instances. Raising the concentration of brine streams by reverse osmosis before discharge can help decrease final disposal costs by decreasing the waste volume [78]. 

I2 A 200L/min stream of freshwater is fed to and withdrawn from a well-mixed tank with a volume of 1000 L. Initially, the tank contains pure water. At time t = 0, the feed is switched to a brine stream with a concentration of 180 g/L that is also fed at a rate of 200 L/min. 

Many specialty chemicals are produced in semibatch reactors where a reactant is added gradually into a batch reactor. This problem concerns the governing equations of such operations without considering chemical reactions. A well-mixed batch reactor initially contains 200 L of pure water. At time t = 0, we start feeding a brine stream with a salt concentration of 180 g/L into the tank at a constant rate of 50 L/min. Calculate ... 

Pp(p x) = the brine stream elasticity depending upon the time of the year (x) and its density (p) or humidity. Pa. 

Radioactive bromine, used as a tracer in a brine stream which was electrolyzed to make chlorine, ended up in the column. It canoentrsited sit the base, and interfered with the sution of the nucleonic level controller, eventusiUy flooding the coltunn. 

The Parsons/HoneyweU technology package is designed to have no liquid discharges, with the possible exception of a concentrated brine stream from the bioreactor effluent evaporator. AU liquid streams are recycled to conserve water, avoid the need for a discharge permit, and mitigate a potential source of public concern. All water introduced into the facility, whether as process water, spent decontamination solution, or water used to wash down equipment, is treated... 

These operations were not tested in Demo II, so this finding remains valid. Experience at the Tooele facility has shown that there may be better alternatives than evaporating brine streams, such as shipping off-site. 

In a comparative study of an integrated hybrid membrane-based system with an earlier locally designed RO unit, such system comprises NF, RO, and membrane distillation (MD) subsystems [79]. The comparison is essentially based on using the NF technique in pretreatment section, while the MD was contributed to concentrate the two brine streams from both NF and RO. Thus, high recovery rate of product water is aimed for. The proposed system was economically evaluated and compared with the RO unit. It was concluded that 76.2% water recovery was possible with a water production cost of 0.92 m . ... 

In seawater desalination, FO offers several major benefits, including high quality of drinking water due to multibarrier protection, reduced RO fouling because of the pretreatment by FO, recovery of osmotic energy of RO brine, low energy input, and no need for chemical pretreatment. Also, high water recoveries (>98%) can be achieved in processes in which RO brine streams are further desalinated by FO [65]. 

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