A Fired Heater (furnace) is a device used to heat up chemicals or chemical mixtures. Fired heaters transfer heat generated by the combustion of fuels. It consists essentially of a battery of pipes or tubes that pass through a firebox. These tubes run along the inside walls and roof of a furnace. The heat released by the burners is transferred through the tubes and into the process fluid. The fluid remains in the furnace just long enough to reach operating conditions before exiting and being pumped to the processing unit. Furnaces are used in crude processing, cracking, olefins production, and many other processes. Furnaces heat up raw materials so that they can produce products such as gasoline, oil, kerosene, chemicals, plastic, and rubber.
A Boiler (steam generator) is a closed vessel in which water or other fluid is heated to generate steam. It has two principal parts: the furnace, which provides heat by burning fuels; and the boiler proper, in which the heat changes water (fluid) into steam. The steam or hot fluid is recirculated out of the boiler for use in various processes operations. Produced Steam is used to operate steam turbines, distillation systems, and reaction systems. They can be used for such processes as laminating, vulcanizing, extrusion, firefighting, and flare systems; and to provide cooling or heating to process equipment. Boilers has two main types:
• Fired Tube Boiler, which resembles a modified shell-and-tube heat exchanger. This type of boiler is composed of a shell and a series of tubes designed to transfer heat from the fire-tubes and into boiler feedwater. Combustion gases exit through a chamber similar to an exchanger head and pass safely out of the boiler.
• Water Tube Boiler, I this type steam is produced by feeding the water under pressure into a tube or tubes surrounded by the combustion gases. A water-tube boiler consists of an upper and lower drum connected by tubes which are surrounded by fire box.