Sodium chloride brine pump

The impeller within a large sodium chloride brine pump in a closed loop system of a chlorine plant needed to be replaced. The job was not assigned to the regular maintenance crew, but... 

After listening intently, the operating foreman explained that mere traces of chrome salts in the brine system could create an explosive situation within the electrolytic chlorine cells. Traces of chrome salts in the feed brine to the chlorine cells liberate hydrogen gas in the chlorine cell gas. Hydrogen in the chlorine cell gas has a very wide explosive range. Installation of stainless steel equipment in sodium chloride brine systems has devastated chlorine processing equipment within other similar chlorine manufacturing plants. The maintenance foreman had the improper pump impeller removed immediately before any problems occurred. 

Production of KCl at the Wendover, Utah operation employs a large 7000 acre complex of solar ponds. Both shallow brine wells and deeper wells are used to pump brine into the pond complex. In the preconcentration ponds water is evaporated and sodium chloride is crystallized. Later the brine is transferred to production ponds where sylvinite is deposited. Brine is then transferred to other ponds where camaUite is crystallized. Sylvinite is removed from drained ponds with self-loading scrapers and taken to the plant were KCl is separated by flotation with an amine oil collector. The camaUite,... 

Fluid loss from the wellbore to the formation may be reduced using the less permeability damaging drilling fluid loss additives described above. In saturated brines, carefully sized sodium chloride particles have been used to temporarily plug the formation face (35). The particles may be dissolved by pumping a less saline fluid down the wellbore. 

Fig. 1. Multiple-effect vacuum pans used in production of sodium chloride from brine. The saturated brine is formed by pumping fresh water directly into the rock salt deposit, leaving insoluble materials in the deposit...

More commonly, salt is produced by the evaporation of natural brines which are formed by pumping water into salt wells and subsequently pumping the resulting brine to the surface. These brines usually contain sodium chloride as the main solute, together with relatively small quantities of other salts, such as sodium and calcium sulfates and potassium and magnesium chlorides. Upon evaporation of the water, the resulting solid therefore consists largely of sodium chloride, but if a purer product is desired, the brine must be suitably treated to remove at least the major portion of the impurities. 

To produce sodium chloride from brine, water is pumped into the salt deposit and the saturated salt solution containing 26% salt, 73.5% water, and 0.5% impurities, is removed. Hydrogen sulfide is removed by aeration and oxidation with chlorine. Calcium (Ca2+), magnesium (Mg2+), and iron (Fe3+) are precipitated as the carbonates using soda ash and are removed in a settling tank. The brine solution can be sold directly or it can be evaporated to give salt of 99.8% purity. 

After several years of operation, conditions warranted the replacement of a pump bowl. The plant warehouse did not stock spare ductile iron pump bowls and none were accessible. A resourceful maintenance supervisor realized that there were a few other large pumps within the plant and they located one. Unfortunately, they chose a cast iron pump bowl which is very desirable for certain sodium chloride (table salt) brine services, but it is totally unsuited for large volumes of highly flammable materials. 

Recommended inhibitor (sodium dichromate) concentrations are 2 kg/m of CaCla and 3.2 kg/m of NaCl brine. Sodium dichromate when dissolved in water or brine makes the solution acid. Steel, iron, copper, or red brass can be used with brine circulating systems. Calcium chloride systems are generally equipped with albiron-and-steel pumps and valves to prevent electrolysis in event of acidity. Copper and red brass tubing are used for calcium chloride evaporators. Sodium chloride systems are using all-iron or all-bronze pumps. 

Compounds of Sodium. The most important compound of sodium is sodium chloride common salt), NaCl. It crystallizes as colorless cubes, with melting point 801° C, and it has a characteristic salty taste. It occurs in sea water to the extent of 3%, and in solid deposits and concentrated brines (salt solutions) that are pumped from wells. Many million tons of the substance are obtained from these sources every year. It is used mainly for the preparation of other compounds of sodium and of chlorine, as well as of sodium metal and chlorine gas. 

A block diagram of the apparatus is shown in Figure 1. The system is constructed to use three sodium chloride anolyte and four sodium hydroxide catholyte concentrations. The starred anolyte compartments refer to separate solutions which have been doped with radiotracer. These solutions are used only for determinations of transport number the nonradioactive brine solutions are used for system flushing and membrane equilibrations. Solutions are selected and pumped into the cell, under computer control, through an all-Teflon pump-valve system. The solutions are heated during these transfers to ensure rapid attainment of experimental temperature in the cell. The brine system is designed to enable the return of radiotracer solutions to their storage vessels after each use. This serves to reduce consumption of radioactive solutions. 

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