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Next generation of waste-to-energy plants increase energy recovery by 20 %
Does it make sense to burn an apple core?
Due to the technology behind flue gas condensation it is now possible to answer “yes” to the question: does it make sense to burn an apple core or any organic waste?
It makes sense because heat and electricity can be generated from the energy content of the core, while also recovering the moisture content. In fact, it makes as much sense to process domestic waste as it does to process other types of biomass, for example wood chips. The moisture content is the same, roughly 35 %.
In the waste combustion process, the moisture content is evaporated, and a considerable amount of energy from the fuel is used. Later on, this energy is recovered in the flue gas condensation system of the plant. It is not only energy that is recovered but also water.
Flue gas condensation increases energy recovery by 20-25 %
The condensation of flue gas in both heat exchangers and absorption heating pumps carries huge gains in energy recovery.
The system condenses the flue gas in the washing tower by cooling the gas, extracting the heat, and sending it to the district heating grid. This process consists of two steps. First, the flue gas is led into a heat exchanger, which cools it down to approximately 50 °C. Then an absorption pump further cools the flue gas to approximately 30 °C. The extra heat extraction provided by the added absorption heating pumps provides a 20-25 % improvement in energy recovery from the waste. For this reason, the investment is quickly paid off. The system can be applied in new as well as existing waste-to-energy plants.
Before 2013, the household waste from the citizens of Helsingborg in Sweden was transported to other waste-to-energy plants in Sweden. But now they can enjoy electricity and heat generated from their own waste.
The main fuel for Filbornaverket is combustible fractions of waste from households, industry and businesses, and the plant makes it possible to use the large quantities of combustible waste from the region to produce electricity and hating for the local grid. Filbornaverket is able to burn approx. 200,000 tonnes of waste per year – with an overall thermal efficiency of close to 100 %. This is possible because of the very advanced flue gas condensation system.