Heat transfer coefficient of graphite falling film absorber

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This post was last edited by baier on 2022-9-29 at 16:42. Among the solutions provided by manufacturers of falling-film absorbers in the current market, the heat transfer coefficient specified is usually 400 W/m2·°C. In the heat transfer coefficient table for impermeable graphite heat exchangers in the \"Handbook of Physical and Chemical Constants for the Chlor-alkali Industry,\" the heat transfer coefficient for hydrogen chloride membrane absorbers is given as 1000–1500 kcal/m2·h·°C. As shown in the book \"Comprehensive Handbook of Chemical Equipment Design: Graphite-Based Chemical Equipment 2003\", the heat transfer coefficient for falling film cooling absorbers is given as 1046.7~1163 kcal/m2.h.°C. As shown in the figure: The question is: Why is the heat transfer coefficient provided by the manufacturer so low? Is it because the design of the falling film absorber is suboptimal, resulting in poor actual heat exchange efficiency? Or, could the heat transfer coefficient of a hydrochloric acid cooler be used instead (in the book \"Comprehensive Handbook of Chemical Equipment Design: Graphite-Based Chemical Equipment 2003\", the heat transfer coefficient for hydrochloric acid cooling at 31% concentration is between 348.9 and 465.2 W/m2·°C). In that case, isn’t this heater actually not a falling film absorber?