FEATURE: RESIDUES TO RESOURCES Bioenergy International No 82, 6-2015 13 sludge, Toulan said. The Tuen Mun facility will have a capacity of 2 000 tonnes per day when fully completed. It will also be capable of generating 14 MW of electricity. According to Gottfried Mittendrein, ANDRITZ’s General Site Manager for the project, the power plant is based on AE&E’s EcoFluid BFB boiler technology to incinerate the incoming sludge. AE&E has supplied four boilers that are arranged in two sets. Each has a 14 MW steam turbine. Some of the sludge is delivered to the facility by truck, but most comes by barge to reduce local pollution. The incoming sludge is dewatered and then fed to the Eco- Fluid boiler plant. The EcoFluid boiler incinerates the organic substances in the sludge, creating ash, flue gas, and heat. Each EcoFluid boiler can generate 27.5 MW from a maximum throughput of 23 tonnes per hour of sludge. The maximum steam output is 31.3 tonnes per hour for each boiler, at a temperature of 383 °C and 42 bar pressure. This means, at maximum capacity, each of the four boilers can accommodate 550 tonnes per day of sludge. At this throughput, the EcoFluid boilers will lower greenhouse gas (GHG) emissions and also reduce the volume of sludge going to landfill by 90 percent. – The EcoFluid boiler is very flexible in its ability to utilise alternative fuels. On average, the dewatered sludge entering the boiler is only about 31.4 percent dry solids. This is sufficient for sustaining incineration in the fluidised bed without having to add fossil fuels or thermally drying the sludge beforehand, said Mittendrein. The flue gas treatment system was designed to meet the strict environmental requirements and emissions standards of Hong Kong. The flue gas goes through a series of treatments before discharge, including a Selective Non- Catalytic Reduction System for nitrogen oxide (NOx) control, a dry reactor for acidic gases reduction, and a multi-cyclone and bag filter system for fine particulates removal. A monitoring station is being installed in the centre of Tuen Mun to continuously analyse the air quality, ensuring that operation of the plant will not have an adverse effect on the environment. Reaching performance The boilers are being commissioned on a staggered schedule and there are two separate performance test periods. – This has been a difficult project. We have had to do a lot of training. Also, we have invested a lot of time working with local authorities to get the necessary permits and authorisations, explained Toulan. Mittendrein said, “I have spent many years in Asia, but this is my first project in Hong Kong. This project confirms my experience that each country is different and that we cannot calculate project costs and schedules using European measures, for example. Everything – construction techniques, available skills, government oversight, and subcontractor quality – is different in each country. We have to do a professional job of managing those resources and delivering a quality power generation system to our customer, said Mittendrein. Toulan has positive things to say about the collaboration. – I am familiar with the ANDRITZ name because my company has purchased their equipment such as decanters, filters, and centrifuges for wastewater projects in the past. The on-site team is a good one. They know what they are talking about. Their equipment is proven and they have been very professional during the design, installation, and commissioning of » “What makes this plant unique in addition to its large size is the building design, degree of self-sufficiency, and educational purposes.” EMMANUEL TOULAN Project Director Veolia Water Solutions Emmanuel Toulan, Project Director for Veolia Water Solutions (left), with Gottfried Mittendrein, ANDRITZ’s General Site Manager for the project, on the public observation deck overlooking the plant and the boilers. Bioenergy International No 82, 6-2015 13
Bioenergy no 6 October 2015
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