High Electrical Efficiency by Dividing the Combustion Products

Abstract

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.

Integrated assessment of a new Waste-to-Energy facility in Central Greece in the context of regional perspectives

“…In cases 4, 5 and 6 the WtE plant is assumed to be a CHP installation and that there is constant annual demand for heat from the (Madsen et al, 2008) were considered. The study found that the increase of steam temperature and pressure could increase the electrical efficiency and more specifically if the temperature increased from 400°C to 500°C and the pressure from 50 bar to 80 bar the electrical efficiency could be increased by 3%.…”

Release of Corrosive Species above the Grate in a Waste Boiler and the Implication for Improved Electrical Efficiency

“…Because of corrosive deposits forming on the superheater surfaces, the superheater steam temperature in WtE boilers is usually kept below approximately 420 °C to minimize corrosion, which would otherwise require frequent replacement of superheaters . At a superheated steam temperature of approximately 380−420 °C and 50 bar, an electrical efficiency of 20−25% is obtained …”

“…In 2005, a few concentration measurements of Cl, Na, K, Ca, S, Pb, and Zn were carried out above the grate at the Vestforbrænding unit 5. ,, Some limitations of the measurement equipment were experienced during those experiments. It was not possible to reuse the probes during the experiments, and therefore, only a limited number of experiments was conducted with no reproduction of the obtained results.…”