Feature Waste management & recycling
Superior handling is key to energy-from-waste plants
In recent years, many energy-from-waste plants have been built in the UK, but the scale of these facilities is often dwarfed by those being established in the most heavily populated regions of the world. The success of these plants depends largely on efficient materials handling systems such as Demag’s automated crane system serving a waste plant in China
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he Luodai Town energy-from- waste plant serves the Chinese city of Chengdu, the capital of Sichuan. Chengdu has over 10.5 million inhabitants, generating 3,600 tons of household refuse every day. The Luodai Town facility processes some 400,000 tons of household waste per year, with the heat produced from the incineration operation used to gen- erate electricity for 50,000 homes in Chengdu. The plant has an output capacity of 120 million kWh and it is estimated that over one million tons of
CO2 emissions will be saved by 2015. In an operation of this scale, contin- uous and uninterrupted incineration of waste material is of paramount importance to the efficiency of the energy-from-waste plant. To meet the special needs of the application and the volume of throughput, the operator specified an intermediate buffer store system, with two overhead travelling cranes, supplied by Demag Cranes and
radeteam ended 2010 on a recycling high after rolling out a waste manage- ment programme to all of its operating sites. As a result, the UK’s leading drinks logistics supplier has more than doubled the proportion of waste recycled last year in comparison to 2009 totals. Marcus Holden Tradeteam finance business partner and environmental cham- pion, who has overseen the ‘go green’ waste improvement project says the achievement has been thanks to a series of specialised identification surveys by parent company DHL’s Environmental Compliance and Solutions (ECS) service. “Following a series of independent waste management surveys we have been able to significantly improve Tradeteam’s ability to identify recyclable materials, implement new solutions and crucially better utilise the resources it currently already employs,” he adds. “Waste segregation programmes and colour-coded recycling stations are up and running at every site and we are recycling
Drinks logistics supplier wins war on waste T
A Tradeteam employee examines baled waste
more glass, shrinkwrap and drink packaging than before. Smaller sites are joining in by utilising our existing transport network, sending waste to balers at larger depots via vehicles bound with customer deliveries for these destinations. “Our Stretton operation now acts as a consolidation ‘centre of excellence for recycling’ and is leading the way by
recycling a massive 95 per cent of all its own waste.” The drinks distributor has also been getting creative with its waste initiatives, supplying Twycross Zoo with shredded waste paper for use as primate bedding, trialling a tiger worm composter for food and organic waste and harvesting rain water from depot roofs to fill-up floor and vehicle cleaning equipment. Tradeteam is also looking to extend initiatives even further this year and is currently researching ways it can support its customers with recycling their own waste at pub level. Tradeteam
T: 01675 468 500 12
www.tradeteam.com Enter 304
Components, for the materials han- dling operations. Both of the fully automatic cranes have a 28.5m span, 16 tons SWL and are equipped with a 10m3 grabbing bucket. Trucks from Chengdu deliver refuse from the plant and deposit the waste into the 19.6 x 84m2 sunken interme- diate buffer store from one of the 12 tipping points. Once the trucks have left the operational area, the automatic grabbing cranes lift newly-deposited
Demag’s automated crane system is being used at a waste-to-energy plant in China
Demag Cranes & Components T: 01295 676177
demagcranes.com Enter 303
material on to existing refuse within the store. By blending different types of waste, optimum calorific values are achieved for efficient incineration and maximum heat output.
The intelligent control system oper- ates on a grid system, dividing the buffer store in to 156 zones, with the position and height of waste in each zone determined automatically. The grid system also provides reference points for the automated crane system, ensuring precise positioning accuracy. The cranes are programmed to dis- tribute refuse evenly above the 45m2 chutes, which feed the three furnaces, ensuring constant and uninterrupted incineration. In addition to feeding the furnaces with up to 50 tons of waste per hour, the grabbing cranes are also required to perform a number of func- tions to blend and clear refuse. To meet the required high cycle rate, the cranes have long travel speeds of 80 m/min, with cross travel and hoisting speeds of 60m/min. The cranes also feature a fully automatic load sway damping system, which not only pro- vides accurate positioning of the grab, but also eliminates the potential of damage caused by the grab colliding with the walls of the bunker walls. The Demag automated crane system provides a low maintenance solution for the particular materials handling requirements of the Chengdu opera- tion, ensuring uninterrupted feeding of the furnaces for constant 24-hour operation. There are also positive health & safety implications of the automated system as there is no need for operators to access the potentially hazardous materials handling area. The success of any energy from waste facility depends largely on the efficiency of its materials handling system. Whilst it is unlikely there will be many plants in the UK as large as the Chengu facility, the principle is the same – it’s just a question of scale.
MARCH 2011 Factory Equipment
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