Vol. 8, No 1, 2011 pp. 51 - 62
UDC 662.2.03:69.002.35:504.06
AN ENVIRONMENTAL AUDIT OF METHYLENE CHLORIDE-BLOWN BATCH AND CONTINUOUS POLYURETHANE
FOAM PRODUCTION PROCESSES: EMISSION QUALITATIVE DISTRIBUTION, AUXILIARY BLOWING AGENT TUNNEL CONCENTRATION AND DIFFUSION COEFFICIENT ESTIMATIONS
L.A. Jimoda
Department of Chemical Engineering, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
lukumanjimoda@yahoo.com
Abstract.
In recent times, foam manufacturers have shifted from using dichloromethane (F-11/CFC-11/CCl3F) as an auxiliary blowing agent (ABA) to methylene chloride (CH2Cl2) since CCl3F was linked to global warming and depletion of stratospheric ozone. Hence, a proper environmental investigation of the behaviour of CH2Cl2 and its associated emissions during polyurethane foam production is necessary since CH2Cl2 is a known animal carcinogen and a suspected human carcinogen. Ambient air sampling of a batch and continuous system was done using activated charcoal as the absorbing medium. Extraction of the collected samples was done in Carbon disulphide (CS2) and its analysis was carried out with an infrared spectrophotometer. A model was used in predicting the tunnel concentrations of CH2Cl2 as a function of formulation, tunnel length, conveyor speed and air flow. The diffusion coefficient of CH2Cl2 within the foaming tunnel was also estimated. An infrared analysis confirmed that the emissions from batch and continuous production processes are made up of CH2Cl2, amine and toluene diisocyanate (TDI) fumes. Also, with decreasing foam density and hardness, the CH2Cl2 feed rate, tunnel air flow and calculated CH2Cl2 concentration (ppm) increase. The diffusion coefficient of CH2Cl2 increases as its temperature within the foaming tunnel increases.
Key Words:
the production process, polyurethane foam, environmental protection
ANALIZA PROIZVODNIH PROCESA STIROPORA IZ UGLA ZAŠTITE ZIVOTNE SREDINE
U novije vreme, proizvodnja stiropora je prešla sa upotrebe dichloromethane (F-11/CFC-11/CCl3F) i agenta (ABA) na metilen hlorid (CH2Cl2). Dakle, pravilna istraga o ponašanju CH2Cl2 i njegovim emisijama tokom proizvodnju poliuretanske pene je neophodna jer CH2Cl2 je poznati karcinogen u životinjskom svetu a postoji sumnja da ima kancerogeno dejstvo na ljude. Uzroci ambijentalnog vazduha uzeti su pomoću aktivnog uglja koji apsorbuje. Prikupljane uzoraka je urađeno uz pomoć Karbon disulfida (CS2) i analiza je sprovedena sa infracrvenim spektrofotometrom. Model je korišćen u predviđanju tunelskih koncentracije CH2Cl2 u funkciji formulisanja dužine tunela, transportne brzine i protoka vazduha. Koeficijent difuzije od CH2Cl2 u tunelu takođe je procenjen. Infracrvena analiza potvrdila je da su emisije CH2Cl2 isparenja amino i toluen diizocijanata (TDI). Takođe, sa opadanjem gustine pene i njene tvrdoće, izračunava se povećanje CH2Cl2 koncentracije (ppm). Koeficijent difuzije CH2Cl2 raste u skladu sa porastom temperature unutar tunela.
Ključne reči: proizvodni proces, stiropor, zaštita životne sredina
