By Les W. Davis, Jr.
Most processes operated by the Petrochemical Industry are driven through the consumption of high-level energy known as HEAT. Heat is produced in enclosed structures through controlled exothermic reactions during the combustion process. The enclosed structures are known as Fired Heaters, Furnaces, Process Heaters, or Pyrolysis Heaters. No matter the name, they all provide the same function: to expose hydrocarbon streams to HEAT which drives a distillation tower, a reactor or, in some cases, change the stream's molecular structure through cracking.
The combustion process consumes large amounts of fuel to satisfy the demand for heat by processes such as Crude Distillation, Reforming, Hydrofining, Coking, Cracking, and Lubes Production. When managers track unit operating costs, they invariably find that fuel cost is among the highest factors. Typical fuel cost was about $2.00/MBtu in the 1Q00 and doubled during the 2Q00 to about $4.00/MBtu. Fuel cost will continue to fluctuate significantly depending on world demand for natural gas and crude oil. Some can remember when the price of fuel was more than $8.00/MBtu in the '70s. It is therefore prudent to effectively manage Fired Heater fuel consumption to insure that fuel waste is minimized.
Consider, for example, a typical 100k Bbl/d crude unit will consume energy of about 75 KBtu/Bbl of feed. If the Fired Heater used to preheat the crude were to have a decrease in thermal efficiency of one percentage point (say 86% to 85%), the fuel cost will increase by about $75k/yr. Fired Heater Energy Management can be stewarded by monitoring the following Key Performance Indicators (KPIs):
During a recent Energy Audit performed at a major refinery, energy losses totaling more than $5M/yr were identified. Carmagen Engineering, Inc. has been asked to assist the refinery in capturing the energy losses. A plan has been implemented to improve overall Fired Heater Energy Management.
It makes sense to reduce fuel consumption from both profitability and atmospheric emissions standpoints. Future articles will discuss the 6 KPIs in more detail.