Equipment corrosion

Because HCl is constandy present in most parts of the equipment, corrosion is always a potential problem. Chlorine and benzene, or any recycled material, must be free of water to trace amounts to prevent corrosion and deactivation of the catalyst. The reactor product contains HCl and iron. In some plants, the product is neutralized with aqueous NaOH before distillation. In others, it is handled in a suitably-designed distillation train, which includes a final residue from which FeCl can be removed with the high boiling tars. 

Only trace amounts of side-chain chlorinated products are formed with suitably active catalysts. It is usually desirable to remove reactive chlorides prior to fractionation in order to niinimi2e the risk of equipment corrosion. The separation of o- and -chlorotoluenes by fractionation requires a high efficiency, isomer-separation column. The small amount of y -chlorotoluene formed in the chlorination cannot be separated by fractionation and remains in the -isomer fraction. The toluene feed should be essentially free of paraffinic impurities that may produce high boiling residues that foul heat-transfer surfaces. Trace water contamination has no effect on product composition. Steel can be used as constmction material for catalyst systems containing iron. However, glass-lined equipment is usually preferred and must be used with other catalyst systems. 

In the late 1980s, however, the discovery of a noble metal catalyst that could tolerate and destroy halogenated hydrocarbons such as methyl bromide in a fixed-bed system was reported (52,53). The products of the reaction were water, carbon dioxide, hydrogen bromide, and bromine. Generally, a scmbber would be needed to prevent downstream equipment corrosion. However, if the focus of the control is the VOCs and the CO rather than the methyl bromide, a modified catalyst formulation can be used that is able to tolerate the methyl bromide, but not destroy it. In this case the methyl bromide passes through the bed unaffected, and designing the system to avoid downstream effects is not necessary. Destmction efficiencies of hydrocarbons and CO of better than 95% have been reported, and methyl bromide destmctions between 0 and 85% (52). 

Actual lifetime of the plant equipment. Corrosion monitoring provides data, which must then be analyzed with additional input and interpretation. However, only estimates can be made of the lifetime of the equipment of concern. Lifetime predictions are, at best, carefully crafted guesses based on the best available data. 

The glycol pH should be controlled to avoid equipment corrosion. Some possible causes for a low, acidic pH are ... 

In summation, MEA systems can efficiently sweeten sour gas to pipeline specifications however, great care in designing the system is required to limit equipment corrosion and MEA losses. 

For facilities that include large numbers of motors and other electrical equipment, it normally is both more economical and more convenient to furnish a building to enclose the required motor starters and distribution panels. This building is normally referred to as a motor control center (MCC). In addition to typically allowing less expensive non-explosion-proof equipment, these buildings are frequently environmentally controlled (air conditioned, and possibly heated in colder climates) to reduce equipment corrosion and enhance reliability. Maintenance is more easily performed indoors than if the equipment were installed outside and maintenance personnel were subject to extreme cold, rain, snow, or other adverse weather conditions. 

Consideration must be given to possible equipment corrosion from such external sources as a corrosive atmosphere, spills, insulation, or gland leakage. For example, insulation containing trace quantities of chlorides can cause stress corrosion failure of 18-8 stainless steel vessels and piping. ... 

Part 1 of Report of Council of British Manufacturers of Petroleum Equipment, Corrosion 1. Cttee, Brit. Petrol. Equipm. News, 1, 54 (1959)... 

Acid Manufacture. Relatively small mostly leakage plus drainings from air pollution abatement scrubbers. Also included are a) acid waters, neutralized with lime or soda ash b) sometimes azeotroping agents such as n-propyl acetate c) sometimes heavy metals from equipment corrosion and d) nitrobodies from acid recovery... 

The chemical events described above are the basis for the removal of arsines (R3 As) in crude oil or in raw gas condensates, which are known to cause major environmental pollution, equipment corrosion and reduction of catalyst life time (including automotive converters). It was recently demonstrated that these compounds can be completely removed by feedstock hydrotreatment on nickel-based catalysts under FI2 at 160-200 °C [140]. 

Sediment usually consists of finely divided solids that may be dispersed in the oil or carried in water droplets. The solids may be drilling mud or sand or scale picked up during the transport of the oil, or may consist of chlorides derived from evaporation of brine droplets in the oil. In any event, the sediment can lead to serious plugging of the equipment, corrosion due to chloride decomposition, and a lowering of residual fuel quality. 

Standard Material Requirements Sulfide Stress Cracking Resistant Metallic Materials for Oilfield Equipment Corrosion Engineers Reference Handbook... 

The reachon of benzene with ethylene or propylene to form ethylbenzene or isopropylbenzene (cumene) is an industrially important transformahon, with ethylbenzene as the key building block for polystyrene and cumene as the feedstock for phenol produchon [55]. Fthylbenzene was originally produced with a Lewis acid catalyst consishng of AlCfi or a Bronsted acidic solid phosphoric acid (SPA) catalyst [56]. Both catalyst systems suffered from equipment corrosion so, in the 1980s the Mobil-Badger vapor phase alkylation process was introduced, which... 

Water and salts can lead to major problems such as equipment corrosion, uneven heating, and equipment fouling. 

Despite the fact that the proposed Lewis-acid IL systems show a very good extraction of DBT, fheir use on indusfrial scale is nof desirable since AICI3 is hydrolyfically unsfable and can cause equipment corrosion. Many attempts have been made to find beffer IL systems for the desulfurization of oil. 

Zinc chloride 97-100% efficiency (higher production rates) (lower energy costs) bright finish accept most chromaters low cost chemistry Reduced ductility over. 5 mil thickness reduced plate distribution high capital cost for equipment (corrosion resistance) tighter chemical control required... 

The slime is additionally a source of production process contamination and production equipment corrosion. Dead organisms in the air stream land on bright steel, aluminum, or other metals, and being hygroscopic, attract moisture, leading to under-deposit and pitting corrosion. 

The main reaction has a lower activation energy, compared to the secondary reactions (Table 9.3). Therefore, low temperature favors the desired reaction. Moreover, equipment corrosion increases at high temperatures. On the other hand, low temperature slows the settling of the acid from the alkylate. In industrial processes, the temperature is around 10 °C. The process designed in this chapter works at -5 °C. This lower temperature could be explained by the inaccuracies of the kinetic data. 

Since operation of TRU began, numerous process changes have been made to counteract problems caused by equipment corrosion, to satisfy new processing requirements, and to utilize improved processes. In initial operations at TRU, unexpected corrosion of the Zircaloy-2 equipment occurred in high specific-activity chloride solutions, and the dissolved zirconium caused operating problems that made some of the flowsheets for the processing steps either difficult to operate or totally unusable. Because of these and other problems, several new flowsheets were devised or adopted, tested, and scaled to pi ant-size equipment. 

However, the introduction of canola left unmet needs for erucic acid in industrial markets. High-erucic acid rapeseed then was imported from Northern Europe for extraction, followed by efforts to increase erucic acid contents in domestic industrial rapeseed as well as development of crambe (Crambe abyssinica) specifically for its erucic acid content. At the current state of development, equipment corrosion and poisoning of hydro-... 

Feedstocks use low Fe, Na and Ca feeds and reduce its acid content to lower equipment corrosion... 

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