Q & A > Question Details
How the Load on Furnace in Crude distillation unit on CIT of Furnace?
In our Furnace the design conditions of CIT/COT are 260/360 C and actual conditions are 250/350.
Is Furnace fired duty depends on Delta T only or is it depends on CIT of Crude?
 
Answers
13/10/2018 A: J ROUT, IPESS, jrout86@gmail.com
The quantum of heat energy required for CIT/COT 250/350 should be less than the heat energy required for CIT/COT are 260/360 C for the same crude oil. Accordingly the fired duty should also change.
12/10/2018 A: Ralph Ragsdale, Ragsdale Refining Courses, ralph.ragsdale@att.net
The fired duty equals the absorbed duty divided by the overall efficiency. The absorbed duty equals the outlet enthalpy of the crude minus the inlet enthalpy. Each of the enthalpies depends on the physical properties of the crude, temperature and pressure. The calculation at each of the two points is called a flash calculation. Today, these calculations are performed by computer programs. Before that, the calculations were made “by hand.” It is probably the first calculation a process engineer learns how to do.
12/10/2018 A: rupali sahu, KBR, rupali.sahu22@gmail.com
Fired Duty depends on Delta H, Delta H depends on CIT and COT; so if CIT and COT are different from design, delta H will change and hence the absorbed and the fired duty.