REXA recently conducted a successful installation on a crude unit heater at a refinery in California. Furnaces help refineries and petrochemical plants break down and convert hydrocarbon fluids into fuels or chemicals such as gasoline, diesel, ethylene and propylene. When making process improvements, these facilities tend to overlook improving furnace draft control. There are many different instruments to choose from when optimizing the draft in a process heater. The challenge, though, is safely elevating process fluid temperature to a target level, maximizing thermal efficiency and throughput and reducing O2, CO and NOx emissions.
This refinery suffered from many damper-related issues. Having 3 furnaces on a single Selective Catalyst Reduction (SCR) unit with all air supplied by one forced draft fan and all flue gas extracted by one induced fan, it’s imperative all dampers operate reliably. This complicated furnace/SCR arrangement includes 3 stack dampers, 3 combustion dampers, a forced draft (FD) fan suction damper and two split induced draft (I/D) fan suction dampers.