Caustic treatment

The mixture is cooled and noncondensable gases are scmbbed with water. Some of the resultant gas stream, mainly hydrogen, may be recycled to control catalyst fouhng. The Hquids are fractionally distilled, taking acetone overhead and a mixture of isopropyl alcohol and water as bottoms. A caustic treatment maybe used to remove minor aldehyde contaminants prior to this distillation (29). In another fractionating column, the aqueous isopropyl alcohol is concentrated to about 88% for recycle to the reactor. 

Caustic Treatment. Amine treatment may be followed by a caustic treatment step in which the LPG is brought into contact with 10—20 wt % caustic solution to remove any residual H2S and to remove mercaptans. The mercaptans may be stream-stripped from the caustic solution, after which the stripped caustic is recycled to the LPG caustic contactor. Caustics that contain H2S must be discarded. Various promoters maybe added to the caustic to improve the efficiency of the mercaptan removal. 

Solid-Bed Caustic Treatment. SoHd-bed caustic units utilizing methanol [67-56-1] injection into the LPG feed stream can be used for carbonyl sulfide removal. The methanol—caustic solution must be drained periodically from the beds and discarded. When the soHd bed is exhausted, the spent caustic must be discarded and replaced. The LPG from the treater has a low enough water content to meet the propane specification. 

Nonregenerative caustic treatment is generally economically appHed when the contaminating materials are low in concentration and waste disposal is not a problem. However, the use of nonregenerative systems is on the decline because of the frequentiy occurring waste disposal problems that arise from environmental considerations and because of the availabiHty of numerous other processes that can effect more complete removal of contaminating materials. 

Steam and calcium hydroxide is formed. If the cooling water tends to form acid ia the boiler, either caustic or phosphate may be added to counteract the effect. When the cooling water tends to form base, only phosphate treatment is appropriate. Many dmm boilers that are operated on AVT have provision for phosphate or caustic treatment duriag condenser leaks because the amines used ia AVT have neither significant bufferiag capacity nor precipitate conditioning properties ia the boiler. 

Figure 7-5. The European Vinyls Corporation process for producing vinyl chlo-rlde " (1) chlorination section, (2) oxychlorination reactor, (3) steam stripping and caustic treatment of water effluent, (4) EDC distillation, (5) pyrolysis furnace, (6,7,8) VCM and EDC separation, (10) by-product reactor.

Mercaptans are the main sulfur compounds in LCN, thiophenes and substituted-thiophenes are present in MCN and benzothiophene (BT) and substituted-BT in the heavy naphthas. A caustic treatment would work for the removal of mercaptans from LCN, and take the total sulfur content below 20 ppm. However, MCN and HCN have to be treated in a more severe way. 

Nonregenerative caustic treatment, 18 661 Nonregenerative processing, of adsorbents, 1 649-650... 

The first step in good pretreatment practice is the segregation of major wastewater streams. This frequently simplifies waste treating problems as well as reducing treatment facility costs. Treatment at the source is also helpful in recovering byproducts that otherwise would not be economically recovered from combined wastes downstream [35]. Four major pretreatment processes that are applicable to individual process effluents or groups of effluents within a refinery are sour water stripping, spent caustics treatment, ballast water separation, and slop oil recovery. These are discussed below. 

Thus -alkanes (C10-C14) separated from the kerosene fraction of petroleum (by urea complexation or absorption with molecular sieves) are now used as one source of the alkyl group. Chlorination takes place anywhere along the chain at any secondary carbon. Friedel-Crafts alkylation followed by sulfonation and caustic treatment gives a more linear alkylbenzenesulfonate (LAS) which is soft or biodegradable. The chlorination process is now the source of about 40% of the alkyl group used for the manufacture of LAS detergent. 

Thermal and catalytically cracked gasoline fractions can contain significant concentrations of phenols, low-molecular-weight organic acids, and alkyl and aryl mercaptans. All of these compounds can initiate gum formation in gasoline. Caustic treatment readily removes these compounds. 

Naphthenic acids occur primarily in distillate and some heavy fuel fractions. Topically, caustic treatment effectively removes these compounds. However, even after caustic treatment, alkali salts of heavier naphthenic acids may still remain oil soluble. In fuel, these compounds can act as very effective emulsifying agents. Fuel haze and particulate contamination can be due to these acid salts. Caustic solutions of various strengths can be used to wash fuel. Usually 10 to 20 vol% of a 5% to 10% caustic wash solution is effective for most applications. 

The mixture leaving the reaction zone is in the form of a hydrocarbon-acid emulsion and passes to an acid settler for separation of acid and hydrocarbon phases. This acid settler is usually a separate vessel from the reactor itself, although it is an integral part of one type of system. The hydrocarbon-free acid from the acid settler recirculates to the reactor. The hydrocarbon layer, which consists of alkylate, excess isobutane, and the inert diluents introduced with the feed, receives a caustic treatment and goes to the fractionating section of the plant. Caustic treatment is necessary at this stage of the process to neutralize acidic components, such as sulfur dioxide, which are formed in small quantities by catalyst degeneration. 

Caustic treatment -mercury m production [MERCURY] (Vol 16) -use m dimethylacetamide purification [ACETIC ACID AND DERIVATIVES - DIMETHYLACETAMIDE] (Vol 1) -in petroleum refining [PETROLEUM - REFINERY PROCESSES, SURVEY] (Vol 18)... 

Natural fiber color is gold. Dyeable to dark shades with basic dyes following caustic treatment. 

The acid gases, usually CO2 and H2S, are removed by scrubbing with diethanolamine or monoethanolamine solutions and possibly an additional caustic treatment. Older processes used caustic solutions of 5-15 wt% NaOH followed by a water wash. Of course, the spent caustic creates a disposal problem it must be neutralized with acid and then properly disposed of according to prevailing pollution and hazard waste standards. Different column configurations have been proposed, but usually large scrubber towers with well over 30 valve-type trays are used. 

Selectivity is close to most effective affinity ligands without issues associated with leachables and instability caused by strong caustic treatments. The cost of this material is significantly lower than any protein A resins. 

Unsaponifiable Matter in Fats and Oils, Including Marine Oils (Ca bb-5, 3) determines substances dissolved in fats and oils that cannot be saponified (turned into sodium salts) by the usual caustic treatment, including higher aliphatic alcohols, sterols, pigments, and hydrocarbons. This method is not suitable for marine oils or feed grade fats. 

It has been suggested that the great depth of color or dye yield found with mercerized cotton is due to the caustic treatment inducing an abundance of large pores in the fiber. In contrast, the high level of resilience associated with liquid ammonia treatment has been ascribed to a low level of large pores in the fiber [292]. 

RELATE GH-50 is useful in caustic bottle washing, alkaline cleaning descaling and derusting of metals, as a cement additive and in the caustic treatment of textiles. 

Scouring agent for use in caustic treatments with high levels of caustic soda. Caustic stability to 18%. Anionic/ Non-ionic. 

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