Steam injection in gas turbines has been used for many years to increase the power output as well as the efficiency of the system and, more recently, to reduce the formation of NOx during the combustion. The major drawback in steam-injection technology is the need of large amounts of fresh water that is eventually lost into the atmosphere along with the exhaust gas. This loss not only increases the operating costs of the system, but also creates other “external” costs in terms of environmental impacts. In order to take advantage of the steam-injection technology and reduce both operating costs and potential environmental impacts, water recovery systems to recuperate the injected steam from the exhaust gas can be implemented. This paper briefly describes the computer models developed at the University of Massachusetts Amherst to optimize water recovery systems. As an example, the optimum size, power requirement and capital cost for two different systems applied to the GE LM2500 gas turbine are shown. Finally, a comparative economic analysis between the costs of installing and operating a water recovery system and the costs of buying and treating water on a regular basis during the lifetime of the project is presented. The results support the economic feasibility of water recovery for mid-size steam-injected gas turbines before having introduced the external costs associated with the use of water resources.
CJ njection mold ing is a commo n method of pla stic processing in which thermopl astic material s can be mold ed int o arbitra ry complex sha pes . Mos t injection molding machines use comp licated hydrauli c sys tems to pe rform the necessar y wo rk of the process. H ydraul ic sys tem flow and pr essure requirem ents va ry th rough out the cycle and in man y cases, excess fluid that is not required by the process is th rottl ed back to the reser voir, was ting motor ene rgy and producing ad di tional thermal load on the cooling sys tem. Variable speed drives can be used to allow injection molding machine hydraul ic sys tems to vary the amo un t of fluid bein g pumped and thu s reduce the amo un t of fluid that is throttled reducing the amount of was ted ene rgy . Th is article discusses injection mold ing machine pro cesses and de velops a protocol for assessing the efficacy of variable speed drive retrofits for hydraul ic injection molding machines.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.