Objective The aim of the project is to demonstrate the applicability and the technical and economical advantages of vertically installed internally rifled tubes. The demonstration will overcome the shortages of investigations on this area. By an industrial furnace testing with a tube-fin-tube construction, installed in the boiler of Unit 7 at Heilbronn power plant, a design basis concerning both heat-transfer and pressure drop for an evaporator with vertically installed internally rifled tubes will be achieved. Computer modelling for the dynamic behaviour will be performed to achieve an optimized design. Experience of manufacturing and operating boilers with rifled tubes will be collected.It is expected that the project provides a sufficient data base for design and construction for an evaporator with vertical tubing and rifled tubes. The boiler built based on the proposed technology will reach lower investment and operating costs. Due to a lower pressure loss, a higher net efficiency of the power plant with the effect of coal savings and emissions reduction can be achieved. Using the technology developed in this demonstration project the competitiveness of the EU manufactures will be increased.Boilers of coal fired power plants which are working with the once-through principle are normally equipped with an enclosure wall for the furnace which acts as evaporator and whose tubes are helically wound. This construction leads to a high mass-flow density (2500 kg/m²s) in the tubes needed for sufficient cooling of the plain tubes. For the technology demonstrated in this project the evaporator is arranged with vertically installed tubes in the high heat flux areas. To guarantee sufficient cooling, the tubes have to be internally rifled because the mass flow is lower (1000 kg/m²s). The smaller tube length for an evaporator with vertical tubing leads to a lower pressure loss and so to lower operating costs.To compensate asymmetric fireside temperatures, a so-called self control effect (also called natural-circulation characteristic) should be active which works if the mass flow density is not higher than 1200 kg/m²s. In such a case the mass flow of a higher heated tube is increased and of a lower heated one is decreased and the temperature differences will be reduced.Because the construction with vertically evaporator tubes is self-supporting there is no need of sling straps. This and the easier erection of such an evaporator leads to lower investments costs.The minimum mass flow density can be decreased to 20% (for helically coiled tubes it is around 35%) of the mass flow at full load. This leads to an easier and shorter strat-up process with reduced strat-up losses. Fields of science engineering and technologyenvironmental engineeringenergy and fuelsfossil energycoal Programme(s) FP4-NNE-THERMIE C - Specific programme for research and technological development, including demonstration in the field of non-nuclear energy, 1994-1998 Topic(s) 5 - SOLID FUELS Call for proposal Data not available Funding Scheme DEM - Demonstration contracts Coordinator EVT ENERGIE UND VERFAHRENSTECHNIK GMBH EU contribution No data Address AUSBURGER STRASSE 712 70329 Stuttgart Germany See on map Total cost No data
