Pressure regulators play an important role in process operations. Wikipedia describes their operation:
I received an advanced copy of a whitepaper, Finding Industrial Pressure Regulators in Your Refinery or Chemical Plant, by Emerson’s Michael Calaway. Michael provides an overview of typical refinery and chemical plant pressure regulator applications and key advantages to the use of regulators.
A pressure regulator’s primary function is to match the flow of gas through the regulator to the demand for gas placed upon the system. If the load flow decreases, then the regulator flow must decrease also. If the load flow increases, then the regulator flow must increase in order to keep the controlled pressure from decreasing due to a shortage of gas in the pressure system.
Industrial regulators are most commonly found in plant utility systems, fired heaters, compressors, and storage tanks. The first area, plant utility systems, include nitrogen, steam, plant air, instrument air, and water systems. Due to their very nature plant utility systems require low cost, low complexity and highly reliable pressure control devices. These requirements make the industrial pressure regulator the primary choice.
For fired heaters including boilers and furnaces, the most common regulator applications are associated with the heater fuel gas system. Regulators are well suited for pressure control of the fuel gas header, burner, and pilot. Michael notes that the need for high turndown, quick speed of response, and reliability make industrial regulators an ideal choice for fired heater fuel gas pressure control. Regulator turndown in some cases can be considered almost infinite allowing for a single regulator to control at minimum fire and maximum fire conditions.
For compressors or other turbo-machinery, regulators are typically used within the compressor auxiliary systems such as lube oil, seal oil, control oil, sealing gas, and buffer gas. Speed of response is critical in these applications to avoid potentially serious issues during process upsets or even normal transient operations such as pump swaps and filter changes.
For storage tanks, regulators are typically used in tank blanketing and vapor recovery applications. Tank blanketing is process of applying an inert gas layer, typically nitrogen, to the top of storage tanks for several reasons including safety, product quality, and tank protection. Vapor recovery is the process of recovering the blanketing gas instead of venting it to atmosphere. A de-pad regulator is a back pressure regulator that keeps the tank from over pressuring by relieving the excess blanketing gas when the tank vapor space become compressed due to tank filling, heating, etc.
Michael closes by reiterating that these critical applications within refineries and chemical plants are where you’ll find that industrial pressure regulators are often the optimal pressure control solution. You can connect and interact with other pressure regulator experts in the Regulators track of the Emerson Exchange 365 community.