Electrolysis and Biomass conversion as options to produce renewable alternatives for fossil lime kiln fuels

Biomass conversion and power-to-gas technologies can be utilized to produce renewable fuels in a pulp mill. These processes can use mill by-products, and can be integrated in an existing pulp production process. This study analyses the effects of integrating the production of gasified biomass, pulverized wood, or hydrogen from water electrolysis in an existing pulp mill process, and compares the possibilities of these renewable fuels to replace fossil lime kiln fuels. As the lime kiln is the only fossil fuel user in a modern pulp mill during normal operation, renewable fuel use would make the mill fossil fuel free. The feasibility of the integration of the processes is analyzed by calculating detailed mass and energy balances for each case using a large South American pulp mill as a reference mill. Economic analysis is performed to estimate the profitability of each integration. The studied technologies are technically feasible to be used for this purpose; the profitability of the options depends significantly on local conditions and fossil fuel prices.