Optimal Design and Modernization of Small Incineration Unit for VOC Abatement

Abstract

In premises of company Momentive Specialty Chemicals, Leuna GmbH & Co. KG an operational thermal incinerator of gaseous waste from the manufacture of products on the base of butadiene-styrene and acrylic-styrene is situated. While producing such mixtures, gaseous vapours are discharged to the waste incineration plant. Gas containing organic substances arises (evaporates from the reactor) especially after transportation of the mixture to the reactor and subsequently at each process steps in the strippers (addition of chemicals, stripping, etc.). The operation of the present unit for processing of waste gas is energetically costly because, for its operation a considerable amount of natural gas is consumed. Therefore, new technologies were sought that could lower the consumption of natural gas and meet the current emission limits. In present time, the existing incinerator has difficulties in complying with the emission limit for NOx. In this case, it seems suitable to replace existing combustion chamber either with the catalytic reactor technology or with a new unit for VOC thermal abatement, or to modify the existing thermal incineration unit in order to meet emission limits (particularly for VOC and NOx), while achieving some savings in terms of operating costs. Currently, the combustion chamber processes two kinds of waste gases - process off- gas 90100 and 90200, which were subjected to technical measurement. These streams differs radically in terms of flow rates and also in terms of composition and pollutants contents trends during production of different kind of products. Technical measurements of waste streams provided the basis for creation of designs that try to deal with the given situation. On the basis of the measured and processed data, data from the operator and simulation of the process in Hysys environment, utmost conditions have been designed, i.e. input values of composition, temperature, pressure and flow rates of waste gases streams 90100 and 90200, for the design of the technology. Possibilities of catalytic oxidation usage for this application or modernization of the incinerator were explored, to achieve reasonable operating costs and meet locally applicable emission limits for VOC and NOx.