Increasing availability and minimising fouling in waste-to-energy plants - Innovative boiler design options

摘要

Raising the efficiency of boiler systems with heterogeneous fuels, such as municipal solid waste (MSW), is on the agenda of almost all plant suppliers and operators. Several options exist to raise the efficiency including elevated steam parameter, steam reheating [1] and external superheating [2]. The reduction of operation and maintenance (O&M) costs, which are strongly affected by fouling, corrosion and erosion issues inside the boiler are also interesting. Reducing downtime and increasing availability have an immediate effect on the plant's economic viability. After having operated MSW-fired boilers for 25 years, the owners of the Bamberg waste-to-energy plant in Germany decided to replace their three units and chose a novel boiler design to improve plant performance. The project was executed from 2007 to 2009. The operational results verify the original expectations of significant improvements in regards fouling, corrosion and plant downtime. In addition to changes in the flue gas flow around the boiler tubes, the boiler tubes themselves can be modified to reduce dust build-ups. The ip tube technology is based on structuring the tube surface. The technology has been implemented in more than 150 reference plants, including thermal oxidisers, evaporators, shell and tube heat exchanger and air preheators. First tests have been carried out in waste-to-energy plant with encouraging preliminary results. New technologies will improve plant performance further but require testing in order to not jeopardise the profitability of valuable assets.