Fuel gas drives the boilers, fired heaters, generators, compressors and more in many process manufacturing and production operations. Accurately controlling fuel gas pressure is important for optimum combustion and overall energy efficiency.I received a draft of an Emerson Exchange Denver conference presentation by Dow’s Tony Dafft, Ryan Baker with Emerson local business partner, Puffer-Sweiven, and Emerson’s Michael Calaway.
The presentation, Fuel Gas Pressure Control: Why a Working Monitor Regulator System?, reviews:
…a natural gas letdown application to multiple process units and discuss why Dow chose a working monitor regulator setup as the new best practice to replace existing split ranged control valves. This workshop will cover the specific application requirements including noise limitations, turndown requirements, speed of response and leakage concerns. In addition, we will review the different types of monitor setups and benefits of each.
They will open sharing some typical fuel gas pressure control applications including fuel gas header, burner gas, pilot gas and minimum fire. The fuel gas header pressure controller is used to maintain a constant fuel gas header pressure throughout the plant or process unit.
Pressure regulators are typically used and typically, pilot operated (pp 596-600) in order to provide a high degree of reliability, speed of response and noise attenuation.A monitor system is any two regulators in series both sensing the same downstream pressure. Upon the failure of one regulator, the other regulator will continue to maintain the downstream pressure. The presenters will describe two types of arrangements:
- Wide-open monitor system
- Working monitor system
The advantages of a wide-open monitor are increased system reliability, simplified testing and overpressure protection by containment. For working monitor systems, the advantages include increased system reliability, both regulators operate, more confidence in monitor takeover, less wear on each regulator, less noise produced due to multiple pressure cuts, and overpressure protection by containment.
The presenters go on to provide a case study of the challenges with controlling fuel gas header pressure at a Dow plant.
If you’ll be joining us October 12-16 in Denver for the Emerson Exchange conference and face similar challenges, you’ll want to catch this presentation and bring your questions. Register by August 15 to receive the Early Bird discounted rates.
If you can’t make it (or even if you can), make sure to connect and interact with pressure regulator experts in the Regulators group in the Emerson Exchange 365 community.