Hydrochloric acid processing plant

HCl, which is for a small part neutralised or processed in a hydrochloric acid production plant ... 

A National Emission Standard for Hazardous Air Pollutants (NESHAP) for new and existing hydrochloric acid process steel pickling lines and HC1 regeneration plants pursuant to Section 112 of the Clean Air Act as amended in November 1990 has been proposed (62 FR 49051, September 18,1997). The purpose of this rulemaking is to reduce emissions of HC1 by about 8360 megagrams per year. 

National Emission Standards for Hazardous Air Pollutants for Source Categories Generic Maximum Achievable Control Technology Standards National Emission Standards for Hazardous Air Pollutants for Steel Pickling—HCI Process Facilities and Hydrochloric Acid Regeneration Plants National Emission Standards for Hazardous Air Pollutants for Mineral Wool Production National Emission Standards for Hazardous Air Pollutants From Hazardous Waste Combustors National Emission Standards for Pharmaceuticals Production... 

Pollutants for Steel Pickling—HCI Process Facilities and Hydrochloric Acid Regeneration Plants Subpart DDD National Emission Standards for Hazardous Air... 

The first hydrochloric acid recovery plant in the world in a refuse incineration plant started operation in the Hamburg BorsigstraBe incineration plant in 1993 [7]. This plant produces high-quality hydrochloric acid from the washed out raw hydrochloric acid. The process is described by M. Schaub from SULZER CHEMTECH AG [8]. Hydrochloric acid which meets the appropriate standards commands considerable prices. 

Historically, soda ash was produced by extracting the ashes of certain plants, such as Spanish barilla, and evaporating the resultant Hquor. The first large scale, commercial synthetic plant employed the LeBlanc (Nicolas LeBlanc (1742—1806)) process (5). In this process, salt (NaCl) reacts with sulfuric acid to produce sodium sulfate and hydrochloric acid. The sodium sulfate is then roasted with limestone and coal and the resulting sodium carbonate—calcium sulfide mixture (black ash) is leached with water to extract the sodium carbonate. The LeBlanc process was last used in 1916—1917 it was expensive and caused significant pollution. 

Hydrochloric acid [7647-01-0], which is formed as by-product from unreacted chloroacetic acid, is fed into an absorption column. After the addition of acid and alcohol is complete, the mixture is heated at reflux for 6—8 h, whereby the intermediate malonic acid ester monoamide is hydroly2ed to a dialkyl malonate. The pure ester is obtained from the mixture of cmde esters by extraction with ben2ene [71-43-2], toluene [108-88-3], or xylene [1330-20-7]. The organic phase is washed with dilute sodium hydroxide [1310-73-2] to remove small amounts of the monoester. The diester is then separated from solvent by distillation at atmospheric pressure, and the malonic ester obtained by redistillation under vacuum as a colorless Hquid with a minimum assay of 99%. The aqueous phase contains considerable amounts of mineral acid and salts and must be treated before being fed to the waste treatment plant. The process is suitable for both the dimethyl and diethyl esters. The yield based on sodium chloroacetate is 75—85%. Various low molecular mass hydrocarbons, some of them partially chlorinated, are formed as by-products. Although a relatively simple plant is sufficient for the reaction itself, a si2eable investment is required for treatment of the wastewater and exhaust gas. 

Benzene Chlorination. In this process, benzene is chlorinated at 38—60°C in the presence of ferric chloride catalyst. The chlorobenzene is hydrolyzed with caustic soda at 400°C and 2.56 kPa (260 atm) to form sodium phenate. The impure sodium phenate reacts with hydrochloric acid to release the phenol from the sodium salt. The yield of phenol is about 82 mol % to that of the theoretical value based on benzene. Plants employing this technology have been shut down for environmental and economic reasons. 

The old Bechamp batch process for reduction of nitroben2ene (iron-hydrochloric acid) is obsolete however, Mobay Chemical Corporation is operating a plant using this process for production of pigment grade iron oxide as weU as aniline. 

Most of the byproduct HCl is used captively, primarily in oxyhydrochlorination processes for making vinyl chloride and chlorinated solvents or for Mg processing (p, 110), The scale of the industry is enormous for example, 5,2 million tonnes of HCl per annum in the US alone (1993), HCl gas for industrial use can be transmitted without difficult over moderate distances in mild-steel piping or in tank cars or trailers. It is also available in cylinders of varying size down to laboratory scale lecture bottles containing 225 g. Aqueous hydrochloric acid consumption (1993) was 1,57 Mt (100% basis). Price for anhydrous HCl is 330/tonne and for 31,4% aqueous acid 73/tonne (1993) depending on plant location and amount required. 

Hydrochloric acid Production, purification, recovery, processing Bayonet heaters, heat exchangers, coils, condensers, HCl absorbers, synthetic HCl plants, acid coolers, gas coolers, chlorine burners, strippers, thermometer wells... 

An account is given of the chemical recycling activities of BASF in a pilot plant at Ludwigshafen in Germany, where mixed plastics waste is processed to obtain hydrochloric acid, oil, gas, naphtha, aromatics and alpha-olefins. 

This paper focuses on feedstock recycling of PVC, which involves degradation in a full-scale incineration plant. Liberated hydrochloric acid is recovered and used in subsequent stages for the generation of new PVC. Full details are given on the basic concept, plant configuration, the process itself, and the economic aspects involved. 

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