Waste-gas purification

The raw material, R, which is not pure, is transformed into A by reaction / —> A + 5. The content of A in crude A is 90.7 %. The laboratory recipe is as follows (1) Dissolve raw material 50 g of / is dissolved in 250 cm (197 g) ethanol at room temperature, while stirring. The required time is approximately 1 h. (2) Reaction In a 1 dm flask, put 250 cm (197 g) of ethanol, and heat to boiling. Over a period of 3 h, let the solution of R drop into the flask, while keeping the ethanol boiling. During the reaction, S is lost as a gas through a cooled trap. There is so much froth that the flask is completely filled. Information about the heat of reaction is not available. At the end of the reaction, cool down the solution of crude A to 40 "C. 25 g of crude A in solution is obtained. Usual precautions must be taken when working with ethanol. Waste-gas purification is required for ethanol. 

Halfmeier, H, Schafer-Treffenfeldt, W., andReuss, M., Potential ofThiobacillus ferrooxidans for Waste Gas Purification. Part 2. Increase in Continuous Ferrous Iron Oxidation Kinetics Using Immobilized Cells, / / / /. Microbiol. 

The exhaust gas must have a temperature of > 300 °C at the exit of the kiln to prevent condensation of sulfuric acid in the ducting. Energy can be saved by recirculating some of the gas to the combustion chamber of the kiln and mixing it with the fuel gases as a partial replacement for air. Alternatively, it can be used for concentrating the dilute acid (see Section 2.1.3.5). The gas then goes to the waste-gas purification system. 

A. Salden, Adsorption/Incineration Process for Waste Gas Purification. 

The plate-and-frame cell design is usually applied to divided cells. Anode and cathode chambers are separated by, for example, a cation-exchange membrane. Anolyte and catholyte have separate circulation systems with separate feeds and outlets and separate waste-gas purification (Fig. 4). 

Waste-Gas Purification by Scrubbing with Glycol Ethers [35]. In the pharmaceutical industry, certain waste-gas streams are purified by scrubbing with glycol ethers. The solvent mixture produced on desorption contains ca. 16 components that are impossible to separate. 

By careful enclosure of the spinning machines and the apparatus in the acid station and by using novel exhaustion systems, the total waste-air stream of 180 000 m /h (STP) has been reduced to 10 000 m /h (STP). The entire spinning machine waste air can therefore be routed via the waste-gas purification plant (CS2, H2S). Lean gas from the acid station is used as combustion air in the sulfuric acid plant. 

Pressure gasification A mixture of CO, CO2, and hydrogen halides is formed at ca. 1600 °C. The hydrogen halides must be separated by waste-gas purification to recover the halogens. The formation of elementary bromine in the gasification process is problematic and would lead to considerable difficulties in waste-gas purification. 

In the biocatalytic process, waste gas purification is not necessary, and no disposal problems involving environmentally harmful chlorine-containing solvents or by-products from the synthesis process occur. 

It can be of practical importance to modify the electronic properties of cheap semiconductor catalysts by doping such that their activity corresponds to that of expensive noble metal catalysts. Two industrial examples of such substitutions are the SCR process (waste-gas purification) and the selective oxidation of methanol to formaldehyde. 

Recycling and Waste-Gas Purification. Solvent recycling is becoming increasingly important for environmental reasons. The following methods may be employed to recover a solvent from a solvent vapor-air mixture but are still uneconomical due to their high costs [14.147]-[14.158] ... 

Varnishing plants are exempt if they employ waste gas purification facilities corresponding to the EU VOC Guideline. ... 

Bubble column reactor 2 Gas separator 3 Cumene column 4 Cleavage reactor 5 Catalyst separation vessel 6 Acetone column 7 Cumene/methylstyrene colunrn 8 Phenol column 9 Hydrogenation reactor 10 Waste gas purification 11 Cracker... 

I Toluene oxidation reactor 2 Waste-gas purification 3 Toluene stripping column 4 Benzoic acid column 5 Benzoic acid oxidation reactor 6 Water-HC stripping column 7 Waste-gas purification 8 Crude phenol column 9 Phenol column 10 Residue extraction ... 

Groenestijn J W and Kraakman N J R, Review Recent developments in biological waste gas purification in Europe , Chemical Engineering Journal, 2005,113, 85-91. 

Wastes from petroleum refining, natural gas purification and pyrolitic treatment of coal Wastes from inorganic chemical processes Wastes from organic chemical processes... 

Adsorbents for water and gas purification and for low level radioactive waste decontamination... 

In 1996, the vendor estimated the cost of treating incinerator fly ash and gas purification filter dust at 150 to 300 per ton. In a confidential 1996 vendor-supplied report, the cost of treating wastes containing toxic heavy metals and wet wastes was estimated at 300 to 1500 per ton. 

Environmental Protection. During the reduction of barite and the calcination of Sachtolith and lithopone, sulfur dioxide is liberated. This is removed from the waste gas in a purification stage which is based on the reversible, temperature-dependent solubility of sulfur dioxide in poly glycol. The absorbed sulfur dioxide can be recovered as a liquid product or as a raw material for sulfuric acid. Any soluble barium in the residue from the dissolution of the fused BaS is removed by treatment with... 

Shell-side effluent from the reforming exchanger is cooled in a waste-heat boiler, where HP steam is generated, and then flows to the CO shift converters containing two catalyst types one (4) is a high-temperature catalyst and the other (5) is a low-temperature catalyst. Shift reactor effluent is cooled, condensed water separated (6) and then routed to the gas purification section. C02 is removed from synthesis gas using a wet-C02 scrubbing system such as hot potassium carbonate or MDEA (methyl diethanolamine) (7). 

Fig. 2.3 Flow diagram ofTi02 production by the k) Evaporator I) TiCU superheater m) O2 su-chloride process, a) Mill b) Silo c) Fluidized- perheater n) Burner o) Cooling coil p) Filter bed reactor d) Cooling tower e) Separation of q) Ti02 purification r) Silo s) Gas purification metal chlorides f) TiCU condensation g) Tank t) Waste-gas cleaning u) CI2 liquefaction, h) Cooler i) Vanadium reduction j) Distillation ...

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