The pulp and paper industry produces large volumes of effluent treatment sludge. The sludge holds water, which makes it expensive to transport and dispose of. Furthermore, there are no energy-efficient methods of incinerating sludge, and the option of sending sludge to landfill will be limited in the future. Valmet’s HTC concept is a solution to these problems.
Reducing sludge management costs
The sludge is transformed into a solid biofuel
Valmet is offering industrial scale HTC (hydrothermal carbonization) plants for sludge treatment. Sludge management costs are reduced while also cutting CO2 emissions. The end result is a sludge press cake ready for burning. It is a solid biofuel, which can serve as a substitute for fossil fuels.
Sludge reduction of 70%
Valmet’s HTC concept is based on a continuous HTC process developed by the German company SunCoal. SunCoal is a technology partner of Valmet and has developed several applications based on HTC.
In the HTC process, the structure of the sludge is transformed, removing chemically bound oxygen and hydrogen as well as intracellular water. Total sludge mass at the start of the HTC process can be reduced by up to 70%, using only 25% of the energy compared to thermal drying. The remaining sludge press cake is explosion-safe and has good handling and transportation characteristics. As a customer, you get an effective solution for sludge management with a reasonable payback time, while simultaneously acquiring a new income stream.
Upgrading of biomass to technical carbons
In addition to sludge management, HTC is also a solution for upgrading biomass to bio-based technical carbons. Biomass or sludge enters a reactor at high pressure and high temperature. Water is removed separately. The drained precursor is then activated to produce activated carbons. One of the advantages of Valmet’s HTC concept is that the quantity of impurities as ash is reduced resulting in a higher yield and higher quality end products or precursor for technical carbons.