Located in southern India, the 2X1,000 GW Kudankulam power plant has set a rather poor precedent for policy makers trying to sell the importance of putting up new commercial nuclear plants to the people of a power-starved country.
(Richard Thomas dealt with shaft rubs in two blog posts: Back to Basics - Rubbing or not and Differentiating between fluid induced instability (oil whirl and oil whip) and a rub. In today's post, he answers a reader's question on how rubs can sometimes lead to reduced vibration amplitude)
Use pressurized dual seals whenever possible in applications that can potentially be hazardous to personnel safety and/or the environment. The use of pressurized dual seals, which require a safe, non-toxic barrier fluid at a higher pressure than the process fluid at the seal face, will positively ensure that the process fluid will be contained, since a positive barrier fluid to process fluid differential pressure will be maintained by the flush system.
Use clean, sweet buffer gas whenever process gas is sour and/or can contain debris to optimize oil seal MTBF (in excess of 120 months).
The entrance of sour gas and/or gas with debris into the oil seal system will expose the seal oil system to the following issues that can reduce seal MTBF, cause unscheduled shutdowns and pose a safety hazard (gas release to the plant environment):
Below are excerpts from a case study presented by Bladimir Gomez, supervisor for rotating equipment engineering at PDVSA CRP Refinery and Barry Snider, president of Small Hammer Incorporated at the 2013 Turbomachinery Symposium at Houston.
In the first part, the author highlighted how VFD technology has become a common feature in compressors. In this article, he explains why the VFD can be advantageous despite being an expensive addition to the compressor system.
This article applies to centrifugal and axial compressors. Reciprocating, screw, and scroll compressors and ejectors have different considerations. For “dynamic” radial or axial gas compressors the predominant noise source is rotating blade passing frequency. There is also noise due to flow turbulence and vortex shedding from stationary vanes and rotating blades. The blade passing frequency is due to interaction of non-uniform flow. Noise levels increase as power increases, but especially as equivalent tip speed goes higher.
Monitor control valve position in all oil systems to determine component wear (rotary pumps, bearings and seals) to ensure corrective action is taken during a turnaround.
Marking the position of control valves (marking the stem and valve yoke with a straight edge) at the beginning of a run will give an instant indication of component wear for the following items:
Ending a manned mission to Mars would represent an engineering feat for the ages. But not far behind in terms of technological innovation is the subject of subsea compression. As the quest for raw materials drives oil and gas companies farther offshore into deeper and deeper waters, at some point it becomes nearly impossible to push hydrocarbons to the surface with the existing degree of natural pressure.
Siemens AG and Dresser-Rand Group Inc. (Dresser-Rand) have entered into a definitive merger agreement under which Siemens will acquire all of the outstanding shares of Dresser-Rand common stock for $83.00 per share in cash.
Axial compressors are modern and compact turbo-compressors for applications with very large flows. They are used in air applications (in air compression units or as an air compressor in a gas turbine), natural gas services and mixed refrigerant applications (in some large LNG plants).
When a fluid, either liquid or gas, is constrained within the space between two concentric cylinders, one rotating and one stationary, the fluid in the clearance between the two cylinders will be set into circumferential motion.
The root cause analysis of vibration problems related to critical turbomachinery is an engineering science based on what is often referred to as the "First Law of Machinery Diagnostics". The 1st Law states that displacement (vibration) is equal to the summation of the dynamic forces acting on the rotor divided by the complex dynamic support stiffness of the rotor bearing system.
A paper by Klaus Brun and Terence Grimley of SWRI, Rainer Kurz of Solar Turbines, and William Folles at ASME/IGTI, 2014 dealt with ‘Experimental evaluation of the effectiveness of online water washing in gas turbine compressors.’ Below are excerpts from the paper.