Evaluation of heat transfer in a catalytic fixed bed reactor at high temperatures

Abstract

Experimental results of fixed-bed heat-transfer experiments with no chemical reaction are presented and discussed. The runs were carried out in a tubular integral reactor heated by an electrical furnace at temperatures in the range of 100 to 500°C. Experimental temperature profiles were determined for the electrical furnace, for the reactor wall, and for the fixed bed center. Industrial catalyst for the prereforming of hydrocarbons was employed as the packing material. The effects of process conditions (furnace temperature, gas flow rate) on the heat-transfer coefficients were evaluated. The experimental results were analyzed in terms of the external, wall, and internal thermal resistances, associated in series, and compared with model predictions. Under the conditions studied, the overall coefficient was mostly a function of the external effective heat-transfer coefficient. An alternative data treatment was proposed to determine the internal heat-transfer coefficient in fixed beds when wall temperature is not constant

CFD Modeling of a Thermally Efficient Modular Reactor for Fischer–Tropsch Synthesis: Determination of the Optimal Size for Each Module

“…In the case of catalytic fixed-bed reactors, the overall heat transfer coefficients range between 100 and 300 W/(m 2 ·K). − In the case of heat transfer coefficients for the catalytic bed, the correlation of h cat = 38 + (0.0255 + 0.055 G ) T w (where G is flow rate/area in kg/(m 2 ·s) and T w is the wall temperature in °C) can be used and the calculated values was ca. 44 W/(m 2 ·K), under the experimental conditions in the present study.…”

Avaliação experimental do coeficiente global de transferência de calor em leito fixo percolado com água

“…, tem-se a solução analítica na forma da Equação 2, conforme apresentado por Jorge et al (1999). Esse modelo contém um único parâmetro ajustável: o coeficiente global de transferência de calor (U), que foi estimado a partir do ajuste do modelo às medidas experimentais de temperatura pelo método dos mínimos quadrados.…”

“…Apesar de a transferência de calor em leito fixo com escoamento de, gases ter sido extensivamente estudada nas ultimas décadas, poucos trabalhos específicos para escoamento monofásico de líquidos são disponíveis na literatura (Lamine et al, 1992).…”

“…1, p. 39-43, 2004 líquidos destacam-se os trabalhos de Lamine et al (1992) e Ferreira et al (2002. Lamine et al (1992) analisaram o comportamento de diferentes correlações para a condutividade térmica efetiva em leito fixo, comparando-as com os seus resultados obtidos em um leito de esferas de vidro, e demonstraram que as correlações obtidas com escoamento de líquidos, quando usadas para gases, são adequadas. Entretanto, as correlações obtidas com o escoamento de gases não apresentaram previsões satisfatórias para líquidos.…”