Mass Balance Determination of Emission Factors for the Production of Sheet Molding Compound

摘要

Sheet molding compound (SMC) is made by dispensing a mixture of resins, fillers, maturation agents, catalysts, mold release, and other additives onto two sheets of carrier film. The lower film, containing a thin layer of paste covered by chopped roving, is joined by the top film sandwiching the fibers between the two layers of paste. SMC manufacturing facilities in Ohio and Indiana are required to conduct volatile organic compound (VOC) emission tests to determine compliance with Title V permit conditions of the United States Environmental Protection Agency (USEPA) Clean Air Act. The purpose of this research is to determine if the styrene emission rates obtained by method 204D, "Volatile Organic Compounds Emissions in Uncaptured Stream from Temporary Total Enclosure," can be predicted by laboratory mass balance models. Data on how emission rates are influenced by airflow, paste temperature, styrene and glass content led to a model that accurately predicted the styrene emission rate of one SMC machine. More data on operating variables and SMC machine setups will need to be collected to determine if the model holds true across the industry.