| 摘要 |
A process for reducing the rate of increase in pressure drop across a furnace convection section, the furnace convection section having a temperature profile. The process includes the steps of establishing a ratio of total dilution H2O to feedstock for the system, injecting a first portion of the total dilution H2O in the form of water into the convection section of the furnace, injecting a second portion of the dilution H2O in the form of steam into the convection section of the furnace, wherein a ratio of dilution H2O in the form of water to dilution H2O in the form of steam is established and varying the temperature profile across the convection section of the furnace by adjusting periodically the ratio of dilution H2O in the form of water to dilution H2O in the form of steam. A similar technique is conducted during decoking to remove asphaltene coke starting from the lower convection section upward. This upward decoking is accomplished by initially using more H2O in the form of water, then as the decoke proceeds reducing H2O in the form of water while increasing H2O in the form of steam.
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