Effect of Cooling Fluid Flow Rate on the Estimation of Conversion by Calorimetry in a Lab‐Scale Reactor

Abstract

Significant information about polymerization reactions carried out in lab‐scale reactors is lost because sampling is not always possible due to the high viscosity, heterogeneity of the reaction medium or pressurization of the reactor. Thus, monitoring these reactions through calorimetry technique could be very valuable. Nevertheless, standard lab‐scale reactors can present a relatively high residence time of the cooling fluid in the jacket and significant heat loss of the jacket to the surroundings. In the present work, the effect of the cooling fluid flow rate on the estimation of conversion through isothermal and isoperibolic calorimetry during a batch emulsion polymerization was investigated. Results show that the estimation of conversion through isothermal and isoperibolic calorimetry was not significantly affected by the cooling fluid flow rate using heat flow calorimetry. Nevertheless, when employing the energy balance of the jacket and the estimation of the global heat exchange coefficient between the jacket and the surroundings to estimate conversion (heat balance calorimetry) better results were obtained for lower cooling fluid flow rates.

On-Line Calorimetry in the Ethylene Coordination Polymerization

“…This method (calorimetric) has been employed successfully in a variety of polymerization reactions [4][5][6][7][8][9]. In a recent report [9], the calorimetric method has been used for the monitoring of ethylene polymerization via metallocenes in a laboratory reactor.…”

Ethylene Polymerization via Metallocenes: An Experimental Study

“…This method (calorimetric) has been employed successfully in a variety of polymerization reactions. [4][5][6][7][8][9] Rincón et. Al.…”

“…al. [5] studied the batch and semi-batch emulsion polymerization of vinylacetate in a 5 liters calorimetric type reactor. They used a Kalman type filter to estimate the heat transfer coefficient as well as the conversion evolution.…”

Avaliação de técnicas calorimétricas aplicadas ao monitoramento de processos químicos.

“…Ao longo dos anos, numerosas revisões e publicações abordando as principais aplicações, classificações, comparação entre os diversos calorímetros comerciais disponíveis, princípios teóricos, modelagem, e a utilização de dados calorimétricos para o diagnóstico e controle de reatores têm sido reportados na literatura incluindo Marti (1977), Regenass (1985Regenass ( , 1997, Rouquerol e Zielenkiewicz (1986), Karlsen e Villadsen (1987a, 1987b, Jacobsen (1990), Schuler e Schmidt (1992), Landau (1996), Zaldívar; Hernández e Barcons (1996), Stoessel (1997), Lebedev (1997), Ferguson et al (2000), Hansen (2001), Stoessel e Ubrich (2001), Randzio (1998Randzio ( , 2002, Zogg et al (2004), Hansen e Hart (2004), Gesthuisen et al (2005), Westerterp e Molga (2006) e Zielenkiewicz (2008).…”

“…Baseado neste modelo, um observador de estado de alto ganho foi utilizado para estimar, simultaneamente, a PSD e o número médio de radicais por partícula polimérica. De acordo com os autores, a metodologia proposta foi capaz de detectar a etapa de nucleação e reconstruir a PSD, mesmo na presença de erros nas taxas de entrada e saída de radicais.Othman e Othman(2006) utilizaram um método de controle geométrico nãolinear multivariado para maximizar a velocidade de reação (R p ) de um processo semicontínuo de polimerização em emulsão. As estimativas da velocidade de reação foram obtidas a partir de um sistema dinâmico composto pelo balanço de energia e pela dinâmica desconhecida de R p e sobre o qual é aplicado os conceitos de observadores de alto ganho.…”