Low-cost Methods to Improve FCCU Energy Efficiency
SUMMARY
The first step to finding low-cost ways of improving FCC unit efficiency under new environmental regulations is to determine the true limits of the existing process equipment and flow scheme, say the authors. They describe ways of influencing heat source temperatures and modifying the flow.
TEXT
Improving FCC unit energy efficiency is becoming more important as refiners try to comply with new government environmental regulations. European and US government mandates are dramatically reducing FCC gasoline sulphur, refinery total NOX and CO2 emissions. Without improved energy utilisation within the FCC, reducing gasoline sulphur will actually increase energy use in the refinery. This will increase CO2 and NOX emissions by increasing the consumption of boiler or new fired heater fuel gas.
Most FCC units were built before the 1970s, when energy costs were considerably lower than today. Low capital cost was the primary investment objective, not efficient energy utilisation. With few exceptions, the capital cost of rejecting heat to air or water is lower than recovering it.
While refinery enregy consumption is a significant operating cost and is closely monitored, investment in improved energy utilisation often cannot be justified by economic factors alone. In today's competitive market, many refiners require revamp payouts of one year or less and the cost of energy does not often meet investment hurdle rates. Increasingly, environmental issues are driving energy efficiency improvments...