Lessons in wood burning
Cemex is well known as an innovator in cement manufacture and its expertise in alternative fuel burning is particularly highly regarded. However, substituting some primary fuel with woody biomass in two relatively old kilns is no easy task, although determined staff at Cemex’s Balcones plant are keen to succeed in such challenges. Cemex tells us the story.
A successful conversion was accomplished in 2002 to burn 80 per cent petcoke and 20 per cent whole tyres at the Cemex Balcones plant in New Braunfels, Texas. It was the first step in a long journey to become one of only a handful of cement plants in the USA that today relies 100 per cent on non-coal feedstock. The switch generated the largest cost reduction from a single project that the company had experienced up to that time, due to the 50 per cent cost savings that petcoke provided compared to coal.
In 2009, plant and corporate managers began discussing the viability of adding woody biomass to the fuel mix. Two years later after a challenging road to success, full of unexpected twists and turns, they proved it could be done.
The Cemex Balcones cement plant operates two kilns, a 32 years vintage air-through system burning petcoke as primary fuel, natural gas as secondary fuel and whole tyres in the preheater tower, which contrasts with Kiln No 2, a modern 3600tpd kiln commissioned in 2008 using the identical fuel mix. Nowadays, biomass presents further enticing opportunities to offset the rising cost of energy and to reduce the carbon footprint, while preserving fossil fuels and saving valuable land for future generations.