Abstract: Control of temperature increase (delta-T) through a reaction zone, in which both exothermic and endothermic reactions are effected, is achieved by sensing the inlet temperature of the charge stock, an intermediate temperature within the reaction zone and the outlet temperature of the effluent from the reaction zone. The inlet temperature sensor co-acts with a temperature recorder controller (TRC) having an adjustable set point, to produce a representative signal which is transmitted to flow-regulating means which adjusts the quantity of charge stock bypassing the feed heater. The difference between the inlet and intermediate temperatures, and that between the intermediate and outlet temperatures are determined to produce two delta-T signals which are transmitted to a double differential temperature recorder controller (DdTRC) which develops a signal representing the difference between the two delta-T signals, compared to a preset difference.

Abstract: Control of temperature increases (delta-T) through a reaction zone, in which both exothermic and endothermic reactions are effected, is achieved by sensing the inlet temperature of the charge stock, a highest temperature from a plurality of intermediate loci within the reaction zone and the outlet temperature of the effluent from the reaction zone. The inlet temperature sensor co-acts with a Temperature Recorder Controller (TRC), having an adjustable set point (control point), to produce a representative signal which is transmitted to flow-regulating means which adjusts the quantity of charge stock bypassing the feed heater. The difference between the inlet and intermediate temperatures, and that between the intermediate and outlet temperatures are determined to produce two delta-T signals which are transmitted to a Double differential Temperature Recorder Controller (DdTRC) which develops a signal representing the difference between the two delta-T signals compared to a preset difference.