FEATURE: RESIDUES TO RESOURCES THE ECOFLUID STEAM BOILER SYSTEMS AT TUEN MUN Bioenergy International No 82, 6-2015 15 their plant. They have consistently met their schedules and commitments, said Emmanuel Toulan. The Tuen Mun facility is currently operating with three boilers and a throughput of about 900 tonnes of sludge per day. This will be increased over the next few months to 1200 tonnes. One thing that has been a bit different than what was expected by Mittendrein is the huge variations in sludge. – We have noticed that the heat value of the incoming sludge changes on a daily basis. One day it will be 3.2 MJ per kg and the next day 4.5 MJ per kg. This demonstrates the flexibility of the EcoFluid technology to handle these large swings, ended Gottfried Mittendrein. Editor’s note: This is an edited version of a client feature commissioned by ANDRITZ and originally published in Spectrum 2/2015. It is used with kind permission. Photos courtesy ANDRITZ. BI82/5000/AS Technology Bubbling fluidised bed (BFB) Ecofluid AC Number of units 4 Fuel Sewage sludge Heating value range 3.0-5.8 MJ/kg Max. fuel heating capacity 27.5 MW each unit Max. sludge throughput 23 t/h each unit Max. steam output 31.3 t/h each unit Steam temperature 383 °C Steam pressure 42 bar The EcoFluid boilers are being commissioned and started up on a staggered schedule. The Tuen Mun facility is currently operating with two boilers and a throughput of about 660 tonnes per day of sludge. Shown here is Johannes Geiger, ANDRITZ Commissioning Manager, checking the instrumentation at one of the boilers. The power plant uses four EcoFluid boilers (bubbling fluidised bed technology), arranged in two sets, to incinerate the incoming sludge. Each has a 14 MW steam turbine. HTC biocoal and phosphorus recovery from sewage sludge The German hydrothermal carbonisation (HTC) developer, AVA-CO2 has announced it will receive support from the German Federal Environmental Foundation (DBU) to set up a phosphorus extraction pilot plant in Karlsruhe. The company is developing hydrothermal processes to produce materials and energy from biomass and its “AVA cleanphos” process has already been successfully tested in AVA-CO2’s laboratories. It will now be tested at pilot scale for the next 12 months, in cooperation with the project partners – the University of Hohenheim and the project group for material cycles and resource strategy at the Fraunhofer Institute for Silicate Research. The project aims to demonstrate that with phosphorus recovery technology, recycling fertiliser with a high, plant-available nutrient content can be produced efficiently and cost-effectively from sewage sludge. According to the company, its recovery technology could prove a breakthrough for the wastewater treatment industry for compliance with the amended German Sewage Sludge Ordinance. The process has the potential to be more efficient and cost-effective than existing methods, as municipal sewage sludge is converted first into HTC-coal before the phosphate is isolated, creating two products of commercial interest – a valuable fertiliser, and phosphorus-free HTC-coal that could be used as a substitute for brown or black coal. – The HTC process, in combination with the AVA cleanphos solution, paves the way for a useful, long-term application for sewage sludge, commented Thomas Kläusli, Chief Marketing Officer at AVA-CO2. For the agricultural sector, the method also offers new possibilities. – Although sewage sludge contains a lot of valuable phosphate, there is a lot to be said against its use in agriculture. It can carry pathogenic substances and contains many heavy metals. Many existing phosphorus recovery technologies incinerate sewage sludge to extract the phosphorous from the ash. However, these methods are more expensive and complicated than the HTC route, said Prof. Dr. Andrea Kruse, agricultural technologist at the University of Hohenheim. BI82/5070/AS ute ean- Cont. from page 13
Bioenergy no 6 October 2015
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