Recausticizing plants operate with a vacuum lime mud drum filter and lime Kiln. The reliable, low cost
operation of this equipment is essential to the success of today’s modern Recaust plants. Moreover, as mills
and equipment are pushed to increase production so is the desire to reduce operating cost. In the Recaust
Kiln area the largest operating costs is the makeup purchased lime required and the fuel required for the
calcining reaction. The major driver of fuel consumption is the water content in the lime mud entering the
Kiln. Reducing the water content in the lime mud is essential to lower operating costs and the requirement
of purchased lime.
By reducing the amount of water fed to the lime kiln by 200 kilograms per tonne of lime per day, approximately $848.00 can be saved. The calculations assume a carbon price of $50 per tonne. Yearly savings in typical 100, 200, 250, 300 tonne per day lime kilns are shown in the following table.
Table 1: Yearly Carbon Tax and Energy Savings for Typical Lime Kilns
| Tonnes Lime | Carbon Price | Natural Gas Price per GJ | Water Reduction | Total Carbon tax and Natural Gas Savings (CND) |
| 200 | $50.00 | $2.50 | 40 | $169,709.00 |
| 250 | $50.00 | $2.50 | 50 | $212,137.00 |
| 300 | $50.00 | $2.50 | 60 | $254,564.00 |
| 350 | $50.00 | $2.50 | 70 | $296,992.00 |
| 400 | $50.00 | $2.50 | 80 | $339,419.00 |