Maximising energy conversion efficiency while minimising environmental impact

How Kobelco handles a diverse range of feedstock, robust operation, and high energy conversion efficiency.
Maximising energy conversion efficiency while minimising environmental impact

Kobelco Eco-Solutions was established in 1946 as a member of the Kobe Steel Group.

Its gasification and melting technology generates renewable energy from waste while minimising environmental impact. This technology can handle a diverse range of waste feedstock with robust operation and high energy conversion efficiency.

Kobelco has 19 proven commercial scale reference plants which have been operating since 2000, and the Technical Research Centre has more than 100 professional engineers and scientists carrying out R&D to support their customers and develop next-generation technologies. 

The KES gasification process is robust and versatile, able to treat a wide range of waste. The waste is fed from the bunker into waste hoppers by the crane and then charged into the gasifier to ensure thermal decomposition. The gasifier has a separation function. Combustibles in the waste feedstock are gasified to generate syngas.

Large incombustibles in the waste feedstock are discharged from the bottom of the furnace by the incombustibles discharger, and then passed down to the sand classifier to separate the large incombustibles from the smaller sand particles. 

The fine sand is returned back to the fluidised bed whilst the incombustibles are transported to the stock yard. These thermally ‘cleaned’ and physically polished materials will then be recycled. Ferrous metal and aluminium can be segregated from incombustibles without being oxidised and melted. The syngas with fine particles leaves the gasifier then passes to the adjacent melting furnaces.

At the top of the melting furnace, air is injected to oxidise the syngas. Because this oxidisation is achieved by gas-gas reaction, little excess air is required, so the flue gas volume is relatively small and energy loss carried away by flue gas is minimised.

As a result, the flue gas temperature goes up to the melting point of ash. Aided by the cyclonic nature of the flows within the furnace, this leads to the molten ash flowing down the wall of the furnace to a ‘tapping hole’.

The molten ash then flows down the tapping hole into the water quench bath. This quenched slag is discharged via a granulator to produce a sand-like slag that is vitrified and therefore non-leachable.