Conceptual design of radiant chamber and preliminary optimization of process tubular furnaces

conference paper

English

Design procedure of process tubular furnace (or fired heater) can be generally divided to three design stages: (a) preliminary design of furnace, (b) detail thermal and hydraulic simulation of furnace and final design solution, (c) mechanical solution of furnace (stress analysis, drawings preparation etc.) First design stage (i.e. stage (a) preliminary design of furnace and cost prediction) is usually connected with proposal for customer when only basic process and furnace design data are usually known. In this design stage it is for the furnace designer very suitable to have at one’s disposal not too detail, however, reliable design method for preliminary furnace design and it’s cost evaluation. Procedure for preliminary design of radiant chamber is usually main part of such design method, because radiant chamber represents basic and dominant part of the today modern process tubular furnace. Conceptual (or preliminary) design of the radiant chamber creates main part of this contribution. Presented method is based on standard long time used design methods (Lobo-Evans method, Belokon’s method). It is shown, how these standard global design methods can be (for common-operating conditions) suitable generalised and simplified. It allows (for purpose of conceptual radiant chamber design) to arrange the basic heat transfer equation for radiant chamber. Derived form of heat transfer equation then allows obtaining basic process and geometrical radiant chamber characteristics of given furnace type (cylindrical, box, etc.) by iterative way. Developed radiant chamber calculating procedure connected with standard procedures for design of furnace convection part and stack (together with cost predictions) is used and the method for quick preliminary evaluation of influence of main design and process furnace parameters (dimensions of radiant chamber and convection part, average heat flux to radiant tubes, absorbed heat in radiant chamber and convection part of furnace, stack size, fuel consumption) on total costs was developed. It allows to optimise the furnace from investment, operating or total cost point of view still in the first (preliminary) design stage of furnace. Developed method can be also used for effective solution of furnace integration into process. Application of the developed method is demonstrated through a case study – optimum design of furnace for crude atmospheric distillation unit.

Process tubular furnace, radiant chamber, optimization

JEGLA, Z.

2004

1. 1. 2004

CSCHI

Prague, Czech Republic

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