Preface 2014
In the years since I assembled the first edition of this book, gas turbine hardware remains, in principle, as it was then. True, a few major manufacturers have developed and released their J-category technology and with this come the refinements in metallurgy and design that help the J machines achieve their rating. OEMs get cleverer with exploring waste fluids for fuel, substituting fluids in case of disasters like earthquakes (air instead of water for cooling), and a myriad of other adaptations. With aviation and marine applications, there are refinements and improvements as always, but the gas turbine itself stays the same in operating principles.
It’s the world in which the gas turbines operate that has changed, not always for the better. I made scant if any mention of the two wars that the United States waged in the 2008 first edition preface, the consequences on the world of that activity and the abysmal economy that started during the 43rd president of the United States’ tenure, thinking all that couldn’t last much longer. Clearly, I’m an optimist. Clearly, I was wrong.
Even the major original equipment manufacturers (OEMs) that were smart enough to survive years of a bad economy and emerge relatively unscathed, had to lose valuable people and expertise in the process. Some OEMs are still reorganizing and acquiring divisions of smaller competitors. Many smaller players and even related industries have gone under. For instance, about ten years ago, the turboexpander was a small but thriving turbomachinery category. Due to the specialized metallurgy it had to develop to handle corrosive or cryogenic fluids, it could have contributed much to gas turbine systems technology. Besides, a turboexpander often used what would have otherwise been a wasted stream of by-product fluid to develop power. Today the few remaining players in the turboexpander business have had to amalgamate and/or downsize to stay alive.
The wars in the Middle East breathed new life into the excess and used machinery business. When restructuring Iraq, for instance, the U.S. development teams would buy out-of-date gas turbine packages that may have had layers of dust on them to put them to use. This was more expedient than ordering new systems.
The wars also shifted attention and development funds to the development of weaponry, surveillance, and other defense electronic systems. World Wars I and II had seen the emergence of the jet engine because of necessity. This then led to the establishment of the peacetime gas turbine business. No similar steep development curve for gas turbine engines came with the Iraq (2003 to 2011) and the Afghanistan (2001 to -) wars.
Since money has been short, gas turbine owners are keener to keep what they already own. This is responsible for some of this second edition’s updates, but relatively little material has been removed from the first edition. The latter’s information is all still relevant. Even in cases where there has been development (like with the J size gas turbines), it is still useful to note the development work that preceded earlier developments. An engine fleet’s history is often a major clue in determining overhaul and fleet management strategy. Consider as well, that in the developing world, many countries still keep the archaic models that came with communism’s or colonialism’s original overlords.
Global evidence of climate change has increased dramatically in the last decade, causing the United States to step up its drive to promote renewables and increase efficiency in fossil-fueled power plants. It is clear that fossil fuels will be around for another half century at least. The “smart grid” that promotes the integration of renewables into the power mix is now being constructed in some locations and then the rest of the world will have to catch up. While still not bending a knee to emissions protocols that were accepted globally, the United States is clearly keen on reducing its emissions and is stepping up incentives and legislation in that vein. “Repowering” (replacing steam turbines with gas turbine combined cycles or even replacing steam turbine coal fuel with gas fuel) is on the increase. The increased availability of gas due to the fracking movement is in part responsible. Since fracking may sometimes be handled by small, ruthless contractors who cut corners and create environmental hazards, fracking has a bad name with the public. If properly regulated and using the technology as it was designed, fracking need not be a nuisance. Further mass increases in drilling will cause seismic unrest below ground that can have consequences of its own, outside of the fracking process.
As a result, gas turbine and gas turbine system developments that favor component life extension, repairability, increased efficiency, fuel flexibility, derating and uprating, working in a hybrid system, better grid distribution, and a host of other items that affect cost of ownership, feature prominently in this second edition. It is clearly a different world than that in which the first edition emerged less than a decade ago. We ought to consider adapting.
The good news is that the gas turbine itself, fuel variations (with different IGCC cycles and experiments with new fuels) notwithstanding, is now a well-developed and relatively predictable beast. When OEMs develop newer models (like the J machines and their CC packages), they do so around a reliable core, albeit with refinements in design, manufacturing, and sometimes performance testing. Some of my OEM friends chuckle at the reduced level of gas turbine expertise among end-users (although there are always exceptions), but quite apart from the growth of power-by-the-hour and similar contracts, the end-user engineer can often get by with knowing less than one had to, two or more decades ago. One friend who retired from a major OEM went back to teach young gas turbine design engineers there and commented that the new engineer workforce would never get to do work as challenging and interesting as those who started their careers anywhere between 1965 and 1985. When I teach courses in industry, I observe that he is frequently right. I also see a trend among engineers and their management wanting material presented in more visual, easier to assimilate teaching formats. My media hobby skills have grown into a set of media resources in case the client requests animations, and digital videos versus static displays, in courses they order.
Does the gas turbine still offer the potential for reduced costs per fired hour? Certainly. Fossil fuels are alive and well and will be in use (although the renewable mix will increase thanks to smart grids and other factors) past the life span of anyone alive today. Refinements with respect to fuel technologies, repair and overhaul, metallurgy, environmental strategy, and emissions economies shall all continue. Emissions taxation and credits will increasingly affect our lives. Coal as “syngas” will continue to be refined as a gas turbine fuel. Hence this second edition.