Evaluating the use of green wood chips processed from small-diameter trees as an alternate fuel for making cement.

To evaluate the possibility of utilizing green wood chips processed from small-diameter trees as an alternative fuel to produce cement, an extended test burn was conducted at the Holcim (formerly Holnam) cement plant north of Fort Collins, Colorado. Over 98 tons of green ponderosa pine wood chips were introduced into plant processes. Approximately 28 tons of green wood was mixed at a rate of 4.7 tons per hour with rock that was fed into the raw mill system at the plant, pulverized, and used to produce cement clinker. Wood replaced an estimated 21 tons of coal. The remaining 70 tons of green wood chips were mixed with coke at a ratio of 1:1 by volume. The wood and coke were then added to coal at a ratio of 15 percent wood and coke to 85 percent coal, pulverized in a coal mill, and used as fuel to fire burners in the calciner and rotary kiln at the plant. The wood in the mix replaced an estimated 54 tons of coal. The wood worked well in existing systems at the plant and no serious handling problems were encountered.