It’s 4 a.m. and the crane operator is a little overzealous, which is starting to show inside the boiler. The bad news is that by the way he’s feeding the chute, it’s only a matter of time until the control room operator loses control of the combustion process, the temperature drops and they’ll face the consequences. The good news, this is a drill. It’s only a drill. And the situation they’re facing is only a simulation. As part of its core training program for plant operating personnel, Wheelabrator Technologies relies on a special computer simulator, licensed from Von Roll Inova, that’s as close to real life as flight simulators are to flying. Just as there’s no airplane to damage as the pilot trains, there’s no boiler. The simulator runs a sophisticated computer program that is identical to the control rooms of the waste-to-energy facilities Wheelabrator operates. It provides users with real-life operating challenges—the good, the bad, and the ugly. Operating scenarios are simulated to exacting standards to provide plant personnel—the plant managers, control room operators, and crane operators—with the ability to respond appropriately to any situation. The simulator allows users to adjust any aspect of operation, from over- or under-fire air to moisture in the virtual trash being fed into the boilers. The process encourages teamwork and allows users to experience situations that could damage property, injure employees or harm the environment. The benefits of the ability to replicate upset and emergency, situations are clear: employees are ready for anything and the instruction helps prevent what would otherwise be downtime or expensive mistakes. The simulator process only works, however, because it’s part of Wheelabrator’s overall training process. The simulator enhances “textbook” instruction in theory and handson qualification checks that all operators receive on a regular basis. It allows them to apply the knowledge they gain from the instruction in the controlled atmosphere of the simulator. Roger Boisse, Senior Manager, Operations Projects with Wheelabrator Technologies, will explain the core operations training program and demonstrate the combustion simulator developed by Von Roll Inova, showing how it can be effective in providing operators with hands-on, and risk-free, experience.

Energy recovery from waste is an efficient way to reduce emissions of greenhouse gas and other gaseous, liquid and solid pollutants and thereby to contribute to a sustainable development. Waste fired power plants are an important part of the European waste management system, and the demands made to modern waste fired power plant are very focused on high electrical output. Lately, Babcock & Wilcox Vo̸lund (BWV) and the CHEC research centre at the Technical University of Demnark has developed a new technology and received a world patent. The basic idea is to improve the electrical efficiency by increasing the steam data. Especially, increasing the steam temperature without the risk of superheater corrosion. The new concept is fully integrated in the boiler and from the outside the waste fired power plant has the same layout as the classic waste fired power plant. The goal is to achieve an increase between 50 °C to 100 °C in the superheated steam temperature and a total increase of electrical efficiency up to 30% without any influence on the normal operation. This paper presents the basic ideas that provide a basis for the patent. The core of the technology is a combination of a new furnace design and a new control system. At the moment, test results from an operating plant support the principal idea. Furthermore, the concept will be studied in the numerical laboratory where CFD simulation will be used to evaluate the technology and to determine the potential process improvements. The final improvement of electricity production has to be determined in the coming test period on a full scale installation, which is currently being planned.

The TURBOSORP ® -process is a dry flue gas cleaning process to remove certain pollutants like SO 2 , HCl, Hg, heavy metals, dioxins and furans. The main principle of this process is to bring flue gas in an intensive contact with Ca(OH) 2 , open hearth furnace coke, water and recirculated material in the Turboreactor. The Turboreactor operates as circulating fluidized bed in the manner of fast fluidisation. The gas/solid mixture leaves the Turboreactor at the top and the solids are separated in a fabric filter from the flue gas. More than 99% of the separated solids are recirculated to the Turboreactor and the rest leaves the process as product. Due to the high sorbent recirculation percentage a high sorbent utilization and low stoechiometric rates are reached in the TURBOSORP ® -process. Due to the fact to have plants in operation for the spray absorption and for the TURBOSORP ® process, a comparison definitely showed advantages for the TURBOSORP ® process. Experiences of the plant start up of a TURBOSORP ® plant in Poland concerning optimisation in pressure loss and hydrodynamics of the Turboreactor using CFD-Simulation are presented. Results concerning mercury and dioxin separation in our Turbosorp ® pilot plant after the refuse incinerator MV Spittelau, Vienna, are discussed.

American Ref-Fuel Company (ARC) spends millions of dollars each year on corrosion related costs in the boilers. The corrosion is caused by chloride salts in the slag that deposit on the boiler tubes, coupled with the high temperatures of flue gas going through the boiler. Corrosion rates are known to be very sensitive to the flue gas temperature and velocity, surface temperature and heat flux through the slag, oxygen in flue gas distribution, etc. These parameters are primarily determined by the firing rate of the boiler, and they are also affected by combustion control and air distribution in the boiler. Some design parameters, such as surface area of refractory, tile, and inconel overlay, also affect the flue gas temperature throughout the boiler, and thereby impact corrosion.

Essex County Resource Recovery Facility (one of American Ref-Fuel Company’s six operating plants) has processing MSW capacity of approximately 2700 TPD and about 60% of this waste comes from NY City. Therefore, availability of the Essex plant boilers is very important not only for the company’s financial performance, it is also critical for the overall garbage disposal situation in the NYC Metropolitan area. One of the main factors affecting plant availability is boiler unscheduled downtime. The most recent data show that approximately 85% of Essex boilers unscheduled downtime is caused by tube failures, the majority of which occur in the superheater tubes. These tube failures are almost exclusively caused by fireside tube metal wastage driven by complicated mechanisms of corrosion in combination with local erosion. The corrosion is caused by chloride salts in the slag that deposits on the boiler tubes, coupled with high temperatures of flue gas going through the boiler. Corrosion rates are known to be very sensitive to flue gas temperature, tube metal temperature, heat flux, flow distribution. Erosion is typically caused by high velocities and flyash particle loading and trajectories. Extensive research revealed that in addition to this typical to WTE boiler corrosion/erosion mechanism, Essex boiler superheater tubes experienced a unique problem, resulting in tube overheating, accelerated wastage, and ultimate failure. In order to address this problem a modification plan was developed, which comprised several redesign options. A specially developed Three-dimensional Computational Fluid Dynamics (3-D CFD) model was utilized for comprehensive technical evaluation of the considered design options and for predicted performance simulations of the selected design at different operating conditions. The economical analysis, conducted in conjunction with the superheater redesign, provided financial justification for this project. The project has been recently executed, and field data collection is still in progress. Some preliminary data analyses have been performed. They have shown that the boiler performance after superheater modification is very close to the predicted target simulated by the CFD model. The plant and the company are already measuring financial benefits as a result of this project, the initial phase of which is presented in this paper.