| Due to high energy costs in recent years, there has been a growing interest in burning alternative fuels in lime kilns at kraft pulp mills. The impacts of alternative fuel use on lime kiln and chemical recovery operations were determined based on information gathered on seven alternative fuels that are currently being used or proposed for use, a lime kiln sulphur balance, and the current understanding of process chemistry. Alternative fuel use was found to affect lime kiln operations in three main areas: lime kiln capacity constraints, lime availability and make-up requirements, and air emissions. Alternative fuel use also affects chemical recovery operations through the introduction of combustion residuals to the cycle. Increasing sulphur and NPE (non-process element) loading in the cycle has specific operational impacts such as increasing sulphidity or causing fouling and corrosion. These impacts may lead to increased make-up chemical requirements or more frequent unscheduled maintenance shutdowns. |
