Waste-to-Energy Keppel Seghers BOILER PRISM Process Overview Waste incineration plants have evolved from pure incineration plants to state-of-the-art installations with minimal environmental impact. The interest is no longer exclusively on the thermal treatment of solid waste, but also the recovery of energy available in the waste. In the energy recovery process, the steam boiler transfers heat present in the flue gas to the water/steam circuit. When leaving the furnace the flue gas flows through the empty passages of the boiler, releasing heat so that the temperature at the inlet of the convection section (final superheater) is less than 650°C. In the convection section, the flue gas further releases its heat such that its temperature at the outlet of the boiler is 200°C or less. Meanwhile, the water inside the boiler pipes is converted into superheated steam. Principle Flue gas from waste incineration contains very aggressive components. The combination of these pollutants and the temperature result in a high risk for corrosion. Therefore, one of the major problems with boilers of waste-to-energy plants is high-temperature corrosion. Since its first installation in 1997, the Keppel Seghers Boiler Prism has proved to be an excellent primary measure against high-temperature corrosion in the empty boiler passages. The Boiler Prism is located at the transition of the combustion chamber to the first boiler passage and acts as a dynamic mixer due to the injection of secondary air. The device is water-cooled, refractorylined and integrated with the natural circulation system o

feeding chute first boiler gass Just above the outlet of the two gas flow sections “A” and “B”, in the shape of a venturi, a flue gas temperature measurement gadget is installed to measure the actual temperature for each flow section. The purpose of this temperature measurement gadget is to maintain, through the combustion control system, almost the same flue gas temperature (ca. 1.000°C) in both sections by means of the variable secondary air flow. ← Boiler Prism Combustion chamber combustion grate Application The Keppel Seghers Boiler Prism is applied in medium to large waste-to-energy plants. The...