Process gaseous effluents

In typical processes, the gaseous effluent from the second-stage oxidation is cooled and fed to an absorber to isolate the MAA as a 20—40% aqueous solution. The MAA may then be concentrated by extraction into a suitable organic solvent such as butyl acetate, toluene, or dibutyl ketone. Azeotropic dehydration and solvent recovery, followed by fractional distillation, is used to obtain the pure product. Water, solvent, and low boiling by-products are removed in a first-stage column. The column bottoms are then fed to a second column where MAA is taken overhead. Esterification to MMA or other esters is readily achieved using acid catalysis. 

W. V. Bush, K. R. Loos, and P. F. Russell, "Environmental Characteri2ation of the Shell Coal Gasification Process. I. Gaseous Effluent Streams," Fifteenth BiennialEow-Rank Fuels Symposium, St. Paul, Minn., May 22—25,1989. 

If an ESP is 90% efficient for particulate removal, what overall efficiency would you expect for two of the ESPs in series Would the cost of the two in series be double the cost of the single ESP List two specific cases in which you might use two ESPs in series The gaseous effluent from a process is 30 m min at 65°C. How much natural gas at 8900 kg cal m would have to be burned per hour to raise the effluent temperature to 820 "C Natural gas requires 10 m of air for every cubic meter of gas at a theoretical air fuel ratio. Assume the air temperature is 20°C and the radiation and convection Iosm s are 10%. 

The quantity of gaseous effluent leaving a process is usually calculated from the continuity equation, which for this use is written as... 

Many of the above processes may potentially be applicable to desulfurization of gaseous effluent streams produced from refining operations. The economics of the processes will have to be compared with existing processes to evaluate their commercialization potential. 

A stoichiometric amount of promoter, at least, is required for the reaction to proceed, leading to an environmentally hostile process with gaseous effluents and mineral wastes. With some metal salts, however, an increase in reaction temperature sets them free from their complex with the ketone, and a true catalytic reaction becomes possible [73] this is observed for iron(III) chloride [74] and some metal tri-flates [72, 75], including their use under the action of MW heating [76]. 

DeNOx (1) A Denox process for removing nitrogen oxides from the gaseous effluents from nitric acid plants. The oxides are reduced with ammonia, over a catalyst containing potassium chromate and ferric oxide. Developed by Didier Werke in the 1980s. 

PuraSiv Hg An adsorptive process for removing mercury vapor from gaseous effluents from the Castner-Kellner process by TSA. The adsorbent is a zeolite molecular sieve containing silver. Developed by UOP... 

REGENOX A catalytic process for oxidizing organic compounds in gaseous effluents. A modified version oxidizes chlorinated and brominated hydrocarbons at 350 to 450°C without forming dioxins. Developed by Haldor Topsoe and first operated by Broomchemie in The Netherlands in 1995. See CATOX. 

SCR [Selective Catalytic Reduction] A general term for processes which destroy nitrogen oxides in gaseous effluents by reacting them with ammonia in the presence of a catalyst ... 

For clean gaseous effluents, such as those from nitric acid plants, the preferred catalyst is mordenite. For flue-gases containing fly ash, the preferred catalyst is titania-vanadia. The process was developed in Japan in the mid-1970s by a consortium of Hitachi, Babcock-Hitachi, and the Mitsubishi Chemical Company, and by the Sakai Chemical Industry Company. It is widely used in power stations in Japan and Germany. See also SNCR. 

Sulfosorbon A process for removing hydrogen sulfide and carbon disulfide from the gaseous effluent from the Viscose process. Offered by Luigi. 

WSA [Wet gas sulphuric acid] A process for recovering sulfur from flue-gases and other gaseous effluents in the form of concentrated sulfuric acid. It can be used in conjunction with the SCR process if oxides of nitrogen are present too. The sulfur dioxide is catalytically oxidized to sulfur trioxide, and any ammonia, carbon monoxide, and carbonaceous combustibles are also oxidized. The sulfur trioxide is then hydrolyzed to sulfuric acid under conditions which produce commercial quality 95 percent acid. Developed by Haldor Topsoe 15 units were commissioned between 1980 and 1995. See also SNOX. 

Processing and Treatment of Gaseous Effluent Streams, 43 Effluent Management, 44... 

Metal parts and dunnage are decontaminated to a 5X level, and gaseous effluents from the hydrolysis processes are treated in the gas-phase chemical reduction (GPCR ) system. 

Cyclone. The first element in the system for DTS gaseous effluent is the cyclone provided to separate large particulate matter that could rapidly plug the downstream candle filters. This element is not required in the system for MPT gaseous effluent. Separated particulate matter is discharged into a steel container through a rotary air lock. The particulates are processed in the MPT to ensure 5X decontamination. 

In its Demo II report, the committee noted that the following gaseous effluents from the SILVER II process were analyzed (NRC, 2000a) ... 

Multiple parallel SCWO reactors are used to process the accumulated hydrolysate held in the SCWO feed tank. Liquid effluent from the SCWO system containing inorganic salts is processed in an evaporator/crystallizer, where salts are concentrated into salt cakes for disposal and clean water is recycled. The gaseous effluent from the SCWO, containing primarily carbon dioxide and oxygen, is scrubbed, monitored, and filtered through activated carbon before being released to the atmosphere. 

The most significant issue, the occurrence of periodic spikes in hydrocarbon and CO measurements in the gaseous effluent, will require further testing to identify the cause and provide a remedy for the problem (see Figure 4-3). The committee considers this problem to be very serious. Resolution must be obtained before the transpiring-wall SCWO process can be seriously considered... 

Wastewaters are generated in the process of scrubbing contaminants from gaseous effluent streams. This water requirement is of significant volume and process conditions normally permit the use of recirculated contaminated water for this service, thereby effectively reducing the discharged wastewater volume. Leaks and spills are routinely collected as part of process efficiency and housekeeping and, in any case, their quantity is minor and normally periodic. 

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