Top Ten Ways to Increase Site Energy Efficiency

By Albert Galgut

Assuming operational efficiency improvements have been realized to a large extent, further increases in site energy efficiency are accomplished via implementation of modest, incremental capital investment opportunities. An energy loss analysis is conducted to quantify energy lost to air / water cooling followed by Process Flow Diagram brainstorming reviews to identify potential capital projects that will reduce fired heater and boiler fuel consumption. Top 10 opportunities include:

  1. Install additional heat exchangers in various feed preheat circuit configurations (e.g., crude, hydrotreater, reformer, light ends, amine rich / lean preheat circuits).
  2. Replace existing bare tube heat exchanger bundles with finned tubes to allow utilizing lower pressure steam in reboilers / preheaters.
  3. Replace existing bare tube heat exchanger bundles with twisted tube bundles to take advantage of higher surface area available in same shell.
  4. Recover energy in various steam utility system streams (e.g., steam vents / letdowns, boiler blowdown, condensate, etc.).
  5. Maximize deaerator feed temperature to reduce deaerator steam demand.
  6. Maximize boiler feedwater temperature to reduce boiler firing.
  7. Install waste heat boiler to generate steam and reduce boiler firing.
  8. Reduce / replace steam utilized in reboilers / feed preheaters with waste heat.
  9. Install mid-reboilers in light ends towers to utilize lower level / waste heat.
  10. Install additional surface in fired heater convection sections to reduce stack temperature / furnace firing.