Fossil free tissue drying Lars Nilsson Karlstad University One possible industrial application of biomass gasification for the pulp and paper industry

Source: www.skogsindustrierna.org

Tissue products - Toilet paper - Kitchen towels - Napkins - Facials - ……….

Tissue drying process Condensing steam inside the cylinder Impinging hot gases

Research questions Is gasification technology commercially available? Will the need for energy gas increase? Effects of process integration?

Scale of the gasification plant Machine speed 1500 m/min Machine width 3 m Grammage 17 g/m2 Press dryness 45 % Creping dryness 95 % Specific drying energy 3,0 MJ/kg H2O Impingement drying contribution 50 % Gas production roughly 2 MW GoBiGas 20 MW (demo) and 100 MW (full scale)

Proposed gasification technologies Updraft fixed bed Downdraft fixed bed Not OK! OK!

Proposed gasification technologies (continued) Suspension gasifier OK!

Proposed gasification technologies (continued) Dual bed gasifier OK!

Proposed gasification technologies (continued) Two stage gasifier OK!

Results from tissue drying model Syngas has a lower heating value than LPG. A higher gas flow is needed. This means that more energy is used for heating the energy gas to the working temperature of the hood. A detailed simulation model has revealed that the increased need for energy gas is lower than 3 % for all cases investigated.

Integrated or stand-alone gasification? Today, steam is produced in a bioboiler. Tissue drying is the main steam consumer. Today´s biomass consumption is 2830 kg/h. Today, LPG for tissue drying is bought. When producing the energy gas on-site, excess heat can be used for steam generation.

Base case energy system

Integrated gasification process

Stand-alone gasification process

Increased biomass consumption for replacing the bought LPG

Benefits of process integration Could the bought LPG be replaced with bought ”green” energy gas?

Research questions revisited Gasification technology is commercially available! - What about burners? Need for energy gas only increases marginally. Benefits of process integration are obvious! - Will ”green energy gas” be available?

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