Joachim Seeber

Advancement in CFB Technology: A Combination of Excellent Environmental Performance and High Efficiency

The CFB technology achieved its commercial breakthrough in the field of power generation in the late eighties as a result of: • very low emissions levels, without secondary measures, that allows the fulfillment of the more stringent environmental legislation; • and the capability to burn a wide range of fuels, that allows the utilization of opportunity fuels.Copyright

Operational Experience With High Efficiency Cyclones: Comparison Between Boiler A and B in the Zeran Power Plant — Warsaw, Poland

The two 450t/h CFB units of the Zeran heat and power plant in Warsaw, Poland, are nearly identical in design, except for the cyclones. While the first CFB unit Zeran A which was commissioned in 1995 had cyclones of a prior design, the second unit Zeran B, which went into operation in late 2001, was equipped with high efficiency cyclones with the latest technological developments. The impact of the cyclone design is clearly visible in the operational data. Due to the high cyclone efficiency, the internal circulation became much higher and the fineness of the circulating particles was shifted to finer particles. As a result, the heat transfer in the furnace was boosted and the temperature profile became more even. This had a significant positive effect on the emissions, especially NOx and on the limestone consumption, which was considerably reduced.Copyright

Pilot Plant Combustion Tests of Low-Volatile and High-Sulphur Coal for the 55 MWel CFBC Cao Ngan Power Plant, Vietnam

Circulating Fluid Bed technology has made a rapid and successful entry into power and steam generation marketplace in many countries. As one of the first CFB based power plants in Vietnam the 2 × 55 MWe Cao Ngan project will follow this trend towards clean coal technology. The Cao Ngan CFB boiler is designed to burn a blend of low-volatile, high-sulphur coals from two local mines complying with strict environmental regulations, 500 mg/Nm3 for SO2 and 300 mg/NM3 for NOx . Combustion tests were carried out at the University of Bochum, Institute of Energy Plant Technology, Germany, in a pilot-CFB combustor (100 kWth ) in order to check the combustion behaviour and the emission characteristics. In these tests a blend of the two different coals was burned at different temperature levels (830 °C, 860 °C, 890 °C) and at each temperature level the desulphurisation efficiency was tested with two different kind of limestone and different Ca/S-ratios: Furthermore the experimental analysis comprised the determination of the conventional emissions (NOx , CO), ignition characteristics for start-up and part load behaviour. During all tests samples of bed and filter ash were taken for further analysis, e.g. burnout, particle size distribution etc.. Earlier comparable combustions tests carried out in the pilot-CFB combustor and large scale CFB boilers has proven, that the results are transferable to large scale commercial plants: This is valid especially for the major emissions e.g. SO2 and NOx . The current paper will explain the design principles and the basic lay-out of the Cao Ngan CFB boiler. In addition, details of the results of combustion tests carried out in a pilot- CFBC at the University of Bochum, Institute of Energy Plant Technology, Germany, will be presented.Copyright