Incineration aqueous effluents

After quenching (5) and energy recovery in a specialized system, products are separated (6) into HC1, which is recycled to oxychlorination, high-purity VCM (7) and unreacted EDC, which is recycled for chlorination (8) and purification (3). Light and heavy ends from the process are converted to HC1 and incinerator. The aqueous effluent from the VCM plant is steam stripped and can be treated offsite to reduce BOD. 

In the case of sewage sludge incineration, chemical wastes have been preconcentrated in the sludge to reduce the aqueous effluents. Current low... 

EXPOSURE ROUTES air emissions aqueous effluent and solid waste products from manufacturing and processing plants incineration of DEP containing plastics ingestion of food inhalation and dermal exposure occupational exposure... 

The hot reactor effluent is sent to a water absorber where it is quenched counter-currently, while unreacted ammonia is neutralized with sutfuric acid. The resulting ammonium sulfate can be recovered and used as a fertilizer. The off-gases containing N2, carbon oxides and unreacted hydrocarbon are sent to incineration. The solution of acetonitrile/acrylonitrile is a heteroazeotrope. After settling, an aqueous and an organic phase are obtained. The first is refluxed, while the latter, rich in acrylonitrile and HCN, is sent to the purification step. The aqueous aceto-... 

Caution is necessary to avoid condensation of an aqueous phase in the system because of the extreme corrosive nature of the liquid phase. Another operating issue concerns mist formation, a phenomenon which occurs very readily when condensing sulfur, and a series of demisters are necessary to prevent this. Residual sulfur is converted to sulfur dioxide by incineration of the tail gas from the process to prevent emission of other sulfur compounds and to dilute the effluent to reduce ground level sulfur dioxide concentrations. 

Firstly, the synthetic processes were assessed to investigate possible reduction in the use of raw materials, solvents and catalysts. Any wastes produced were then studied with respect to solvent recovery by distillation and reuse in the original process. Parts of the waste not reusable were assessed for separation and sale to third parties for recovery and reuse. Finally, any non-recoverable wastes were assessed for incineration with consequent heat recovery potential. Safe physico-chemical aqueous treatment processes for the final effluent then became minor and relatively cheap. An important factor in the total approach was to determine the cost-effectiveness of each recycling possibility. If internal use was not viable, then the marketing department attempted to find alternative outlets or, as a last resort, the energy value for steam co-generation by incineration was extracted. 

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