- May 06, 2010
- GE Digital
Anti-Surge Protection and Capacity Control of Centrifugal and Axial Compressors May 6, 2010 - The Oil & Gas and Petrochemical industries are trending toward systems integration to lower O&M costs while improving performance and reliability. One example is in the area of centrifugal compressor operation, where hundreds of compressor units can be operating individually, as a machine train, or as a major subsystem in support of the overall hydrocarbon processing at a large industrial complex. Centrifugal compressors quite often are high energy-consuming, high-speed machines, where critical control and protection are required to operate safely and efficiently through their required operating scenarios. A specific phenomenon in turbocompressors is called “surge.” Surge can be described as large and self-sustaining pressure and flow oscillations in the compression system that occurs when the flow through the compressor decreases below a certain level. This level varies with the operating parameters of the compressor and with the gas properties. Unstable behavior of the compressor results from the interaction of the compressor characteristics and those of the surrounding system, as well as from the loss of aerodynamic stability in the compressor itself. The often-violent flow reversals due to surge can destroy bearings, seals, and other internal components, resulting in significant repair costs, and most importantly, the financial losses due to lost production. Finding the right balance between process performance and surge protection can be challenging. In the past, control strategies stressed “playing it safe” by keeping a compressor operating well above its surge flow. Today’s competitive realities demand more – maximizing the overall process efficiency by safely operating compressors closer to the surge limit, without the risk of crossing over the line. GE Energy has developed advanced control technology, which integrates the control functions such as turbine speed, sequencing, and compressor anti-surge protection into a single control system. This integration is now moving further with the convergence of machine condition monitoring and compressor control. This is enabling plants to operate their compressors and process closer to the “optimum” point, without surge and providing protection over the full range of operation, maximizing process efficiency. GE calls this latest technology, OptiComp BN - Integrated Compressor Control. The concept is patent pending and is in the final detailed design stage for full disclosure later this year.