Combined Heat and Power in Chemical Recovery

By installing a combined heat and power (CHP) system, using an extraction back pressure and/or extraction condensing turbine, the heat content of the black liquor can be converted both to electricity and heat. This will significantly increase the amount of useful energy extracted from black liquor, thereby helping reduce the need for electricity or fuel purchase.

See also Combined Heat and Power Generation, for more information on the applications of this option in the pulp and paper industry. 

Development Status Products
Chemical Pulp

Combined Heat and Power in Chemical RecoveryCosts & Benefits

Parent Process: Chemical Recovery
Energy Savings Potential

While in conventional power plants only less than 40% of the energy input is converted into electricity – and the rest of the energy is wasted –in cogeneration facilities 80-93% of the energy input is converted into 40-70% heat and 20-45% electricity.

CO2 Emission Reduction Potential

The CHP can reduce CO2 release rate by 50% compared to conventional power generation systems (BREF, 2010. p. 542).


The specific investment cost for transforming existing steam back-pressure units into combined cycle cogeneration plants is estimated to be EUR 1000/kW. The achievable savings and the payback time depend mainly on the price of electricity and fuels within the country.