A New Treatment Plant for China
The mechanical biological treatment (MBT) plant for municipal solid waste (MSW) in Lianyungang is under construction. The completion is scheduled for the end of 2017.
More than 200 waste-to-energy (WtE) plants are operating in China nowadays. One of them in the City of Lianyungang, Shandong Province north of Shanghai, will be complemented by a pre-treatment plant for municipal solid waste (MSW). The Austrian-German technology firm Redwave designed the process of the entire plant. In China household waste has a different composition in comparison to Europe. It has a relatively high content of organics and moisture, so when incinerated a lower energy efficiency is achieved. Depending on regional conditions the calorific value of MSW in China is in the range of 3 to 6.7 mega joules/kilogram, which is far less than the 9 to 11 mega joules/kilogram in Europe. According to Redwave, the client China Jinjiang Environment Holding Company Limited placed the order for the supply, installation and commissioning of the Lianyungang MBT plant (mechanical biological treatment). It is designed for an annual throughput capacity of 273,750 tons based on a daily input of 750 tons. “The client’s request was to increase the calorific value by drying the waste from an incoming moisture of 50 percent to a maximum moisture content of 30 percent,” the provider gave account.
The process
Starting from a deep bunker a fully automated delivery crane conveys the waste into the hopper of the pre-shedder. Via an overbelt magnet for ferrous separation the pre-shredded material is fed to an intermediate bunker. From there a fully automated overhead gantry crane conveys the waste to one of the 18 bio-drying units. When ambient or re-circulated air ventilates the material in the box it heats up by an aerobic microbiological process. The water is discharged of the drying box in the form of water vapor and the dry material remains in the box. Due to the individual control of each box it is possible to guarantee even and efficient drying. The relevant data like the flow rate of circulated and fresh air, heat output capacity and the temperature curves are analyzed in the process control. Each bio-drying unit has a removable lid on top designed as self-supporting insulated steel structure. The drying process inside the unit proceeds independently from the outside climatic conditions.
After the bio-drying, the dried waste is processed in various steps including screening, airstream sorting, shredding, overbelt magnets, eddy current separators (ECS) and Redwave sensor based sorting systems and is turned into a high quality homogenous solid recovered fuel (SRF) with a calorific value of approximately 12 to 14 mega joules/kilogram.
Photo: Redwave
GR 22017
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