An industrial heat exchanger is a device that is specially designed for heat transfer between different media. One medium is process fluid and the other is a heat-absorbing coolant comprised of chilled liquid or gas.
The heat exchangers used in various steps in the processing of oil and natural gas are subject to severe environmental constraints and high pressures. Heat exchangers must satisfy demanding reliability requirements because of the types of fluids in them (flammable, explosive, harmful to the environment, etc.).
Oil & gas upstream and downstream processing places special demands on heat exchangers. Such equipment must not only withstand corrosive media, two-phase mixtures, extreme pressures and temperatures, but also be extremely compact.
Typically, heat exchanger removes the heat generated by an industrial process helping to cool it off and prevent an unchecked rise in production temperature.
Alternately, a heat exchanger may also be used to heat a production reaction where higher process temperatures are required. This function of a heat exchanger is less commonly employed than its application in industrial cooling.
Heat exchangers function by bringing a cooled fluid into close contact with a hot industrial process or piece of equipment. This allows for an exchange of the heat between the two mediums by using the principles of thermal heat conduction.
In some cases, the media (coolant and heated process) are in direct contact but for the majority of heat exchanger types, there is usually a separating barrier between them.
Industrial heat exchangers can be classified into three broad groups based on:
The manner of heat exchange
The physical states of the interacting fluids
The design/ flow pattern of the heat exchanger
Types of Heat Exchangers
Shell and tube heat exchangers.
Double pipe heat exchangers.
Plate heat exchangers.
Condensers, evaporators, and boilers.
Shell and Tube Exchangers
A shell and tube heat exchanger is essentially a collection of tubes enclosed within a pressurized outer shell. This device works by channeling one fluid (typically from the hot process) through the smaller tubes and the other through the outer shell to achieve heat exchange.
Evaporators and Boilers
These heat exchangers undergo a biphasic heat transfer process which changes the physical state of one or more of the fluids involved.
Double Pipe Thermal Exchangers
The double pipe heat exchanger set up consists of two concentric pipes; a smaller diameter pipe running within a larger one, which brings two fluids into proximity. For maximum efficiency, the heated and cooled fluids circulating within both pipes are driven in opposite “counter-current” directions.
Plate Heat Exchangers
Plate heat exchange devices are composed of several thin plates arranged together in stacks. These plates create channels through which the interacting fluids can flow.
While typical plate exchangers allow for heat exchange between just two fluid media, variation such as the plate-fin exchanger permits multiple fluid streams through its parts. The pillow-plate exchanger variant raises the pressure within the exchange system to improve efficiency.
Heat Exchanger Applications in Oil and Gas
Hot oil/heat transfer systems
Fuel gas conditioning skids
Cold ammonia flow control
Lube oil systems
SCR units
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