WTA technology for drying of lignite coal Jul27

WTA technology for drying of lignite coal...

WTA technology for drying of lignite coal WTA (Wirbelschicht Trocknung Anlage) technology for drying of lignite coal has been developed by German company RWE Power AG. WTA is the German abbreviation which stands for fluidized-bed drying with internal waste heat utilization. RWE Power AG holds a good number of patents on this technology. The first steam-fluidized bed dryer was developed by RWE as the WTA-1 demonstration plant at Frechen near Cologne, Germany,  with a throughput capacity of 53 tons per hour of raw lignite coal having a grain size of 0 mm to 6 mm and an evaporative capacity of 25 tons per hour. During the 20,000 hours of test operation from 1993 to 1999, the WTA-1 demonstration plant along with the vapour compression system for drier heating (employed for the first time worldwide in lignite coal applications) has proved to work extremely well and reliably. Further theoretical work and an evaluation of the test operation of the WTA-1 plant revealed further potential for the technical and economic process optimization. Several alternatives of development were considered and it was revealed that a reduction of the grain size held most potential for further improvement. In 1999, RWE built a test plant called WTA-2 for the fine grained WTA process directly next to the WTA-1 plant in Frechen. This new plant had a design capacity which was increased in several optimization steps from originally 16.4 tons per hour of raw lignite coal throughput and 8 tons per hour evaporation capacity to a raw coal throughput of 28.7 tons per hour and a water evaporation capacity of 13.1 tons per hour during the total of 8,200 hours of operation of the plant by 2011. Based on the extensive experience from the operation of the WTA-2 plant with...