Welcome to the peer-reviewed section of this year’s last issue. It is hard to believe that the year is almost behind us, although for many in the industry, 2015 cannot come to an end soon enough. This year can easily be classified as a brutal year, and a year that has put our industry in a different light. I can only hope that the downsizing will end soon and be followed by a time when new approaches and new technologies will provide plentiful opportunities. And I think that these papers provide some very interesting examples of potential innovations.
The first paper deals with thermal enhanced oil recovery steam-generation projects, covering not only the traditional (heat recovery) steam generators, but also steam generators powered by solar energy, which is definitely a new approach and has been used at three locations around the world. The paper provides detailed performance and economic models that may be used for each option to determine the optimal solution for a given application. These models are then applied in a case study to provide a better understanding of the suggested approach.
The second paper illustrates a new and innovative design of a bypass pig. It is common knowledge that compared with conventional pigging, bypass pigging reduces the damaging effects of the pig-generated liquid slug by redistributing gas and liquid in the pipeline. A new convergent/divergent bypass pig geometry/profile has been developed, and with this innovative design, a critical and constant gas flow rate is achieved at a lower pressure ratio through the bypass hole. Adopting such a bypass-hole profile with suitable geometry can ensure the required bypass-gas quantity through the pig, avoid pig stalling, and minimize process upset, thus ensuring better pipeline cleaning.
The last two papers do not directly deal with innovations, but instead provide a better understanding of two topics that could potentially lead to future innovations. The first deals with bolting failures resulting from hydrogen stress cracking when the bolts are exposed to hydrogen-bearing environments, such as seawater with cathodic protection, or as a result of insufficient baking after plating operations. This paper describes the mistaken, but long-held, belief that because rolled threads are beneficial for fatigue resistance, they are, at best, not injurious to the performance of bolting when there are other causes of failure such as environmental cracking.
The final paper covers failures of dry-gas seals that are not caused by the seal design, but instead by factors peripheral to the seal. The need for pressurized seals necessitates the evaluation of possible sources of gas supply during normal operation and startup. Possible sources of supply evaluated in this study include high-pressure gas-export pipeline, multitrain arrangement to supply gas from the operating train to the standby train, and the use of gas boosters. The paper discusses the possible presence of various contaminants in the gas supply, and suggests treatment methods as well as other design considerations, such as reverse rotation, depressurization limitations, and reverse pressurization. Finally, it offers recommendations for interfacing with the compressor vendor from the process system design and operation perspectives.
I hope that you will not only enjoy these papers, but be encouraged to apply these innovations and insights on projects in the years to come.
Gerald Verbeek, Peer-Review Editor,
Verbeek Management Services
Williams Chirinos, Inexertus
Galen Dino, Audubon Engineering Solutions
Sudhakar Mahajanam, ConocoPhillips