Title

RESEARCH ON THERMAL PROCESS TECHNOLOGY OF NON / HEAT RECOVERY COKE OVENS

RESEARCH ON THERMAL PROCESS TECHNOLOGY OF NON / HEAT RECOVERY COKE OVENS

Authorship

Kim, Ronald; Schulte, Helmut; Worberg, Rainer

Kim, Ronald

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Schulte, Helmut

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Worberg, Rainer

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DOI

10.5151/2594-357X-17174

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Abstract

UHDE has decided to validate and broaden the design criteria for heat recovery technology with an in-depth theoretical investigation of the process using various mathematical models. A two-dimensional, transient coking model was developed for industrial application to allow key influencing quantities of the heat recovery coking process to be recorded and the main process parameters, such as “end of coking process”, to be predicted. The thermo-physical properties which characterise the coal/coke cake and ash - i.e. thermal conductivity, specific heat capacity cp and density – were determined on a temperature-dependent, effective basis by means of heat flow balance calorimeter measurements and LFA analysis. The model also enabled the limits of application for this coking technology to be worked out with respect to the process parameters, and characteristic temperature profiles in the upper and lower parts of the oven to be illustrated dependent on the primary and secondary air adjustment as well as the total excess air amount specified, taking into account full process and geometric coupling between the upper and lower parts of the oven. Two ovens based on the UHDE design at ICC’s non-recovery plant were used for practical validation of the computed temperature profiles in the coal/coke cake by means of tar joint measurements. In order to achieve an optimized design for the air inlets and downcomers with respect to an even surface heating of the cake, a complex mathematical flow and staged combustion model based on a finite volume analysis was designed. This enabled the mixing and combustion process inside the oven chamber to be observed through graphical animation and led to an evolutionary improvement in understanding of mixing and combustion laws within the oven.

UHDE has decided to validate and broaden the design criteria for heat recovery technology with an in-depth theoretical investigation of the process using various mathematical models. A two-dimensional, transient coking model was developed for industrial application to allow key influencing quantities of the heat recovery coking process to be recorded and the main process parameters, such as “end of coking process”, to be predicted. The thermo-physical properties which characterise the coal/coke cake and ash - i.e. thermal conductivity, specific heat capacity cp and density – were determined on a temperature-dependent, effective basis by means of heat flow balance calorimeter measurements and LFA analysis. The model also enabled the limits of application for this coking technology to be worked out with respect to the process parameters, and characteristic temperature profiles in the upper and lower parts of the oven to be illustrated dependent on the primary and secondary air adjustment as well as the total excess air amount specified, taking into account full process and geometric coupling between the upper and lower parts of the oven. Two ovens based on the UHDE design at ICC’s non-recovery plant were used for practical validation of the computed temperature profiles in the coal/coke cake by means of tar joint measurements. In order to achieve an optimized design for the air inlets and downcomers with respect to an even surface heating of the cake, a complex mathematical flow and staged combustion model based on a finite volume analysis was designed. This enabled the mixing and combustion process inside the oven chamber to be observed through graphical animation and led to an evolutionary improvement in understanding of mixing and combustion laws within the oven.

Keywords

Transient process model; Combustion and flow simulation; Measurement of the thermo-physical properties of coal and coke; Measurement of temperature distribution; Design of primary air supply.

Transient process model; Combustion and flow simulation; Measurement of the thermo-physical properties of coal and coke; Measurement of temperature distribution; Design of primary air supply.