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From: atc/nc cat
Category: Safety
Date: 07 Jan 2005
Happy New Year 2005 Mr. Squirrel! I thought the primary objective of what you suggested is to reduce the effect of externally deposit of the heater tube. Less firing rate less residue that could be deposited on the external heater tubes and less hi temp. stress corrosion. As an example, is it not that we still maintain the temp. of the heater outlet to say 920 deg. F? We tweak the outlet temperature depending on what you want to accomplish i.e., increasing temp. of heater outlet to reduce foaming and lowering the temp. of the heater outlet to attain less shot coke? Is it not the target heater outlet still be relatively the same considering the thermal cracking temp. of the feed? I thought fouling rate of the heater tube internal depends on flow rate and heater outlet temp. being maintained assuming heater heat transfer is normal.