Real situation 

The hydrocarbon product, after exiting the reactor,  has a temperature of about 329oC. It is then subject to heat recovery together with the input materials at E-1201A-H and cooled by air at E-1202A/B (whose capacity is about 5 mmkcal/hour) to 48oC. Then it moves to D-1203 separator.

Consider installing hot separator after the hydrocarbon product exits from the reactor and is subject to heat recovery by E-1201A-H into liquid flow and gas flow. The gas flow is further cooled by the E1202A/B heat exchanger and then separated at a low temperature by D1203. The liquid flow will combine with the liquid flow from D1203 and continue to be heated before entering T1201 tower.

The hydrocarbon product from R-1301/2/3/4 reactor having the temperature of 495oC is subject to heat exchange with the input material flow at E-1301/1302. Its temperature drops to 114oC. Then it continues to be cooled by E-1303A-H (whose capacity is about 12.11 mmkcal / hour) to 43oC, before entering D-1301 separator.

Consider installing an additional heat exchangers taking advantage of the heat of the hydrocarbon product from R-1301/2/3/4 reactor after it is subject to heat exchange with E-1301/02 to heat the Debutanizer material, instead of the high temperature flow from the bottom of Debutanizer tower. The high temperature flow from the Debutanizer bottom will be used to heat the Ligh-Heavy Naphtha Slipter / T-1202 bottom, instead of using MPS medium pressure steam.

Currently, crude oil-fired heating furnace (H-1101) is insulated with refractory bricks, to minimize heat loss to the environment.

Consider applying the "High emissivity coating" to the CDU to increase its thermal radiation coefficient, ability to absorb heat and reduce heat loss to the outside, leading to increasing thermal efficiency from 1-3%. Each 1% increase in thermal efficiency will reduce fuel consumption by about 0.9 mmkcal/hour