Issue introduction

The burning zone of a rotary lime kiln has the highest process and shell temperatures of anywhere in the kiln. Increasing production by increasing burning temperatures necessitates the selection of higher quality basic wear lining brick (improved thermochemical resistance) to optimise the refractory campaign life. Such bricks also have higher conductivity and, with minimal coating formation, shell temperatures are further increased. The resulting high shell temperature can cause shell deformation, increased energy consumption, loosening of the refractory lining and rotational and migration issues. Until now, dedicated insulation linings have not been used in such intensely thermomechanically stressful applications due to their inherent softness and fragility. Rotary kiln lime producers have to tolerate unacceptably high shell temperatures and energy consumption in order to achieve increased production targets. To correct this, a 13mm thick structural insulation board manufactured by Pyrotek, with world’s best thermomechanical properties, was trialed in order to reduce the shell temperatures. Its performance was assessed over a three year campaign.

Environmental legislation is becoming more stringent and requires industrial mills to refer to best available technologies (BAT) and practices in order to achieve enhanced performance from existing equipment. Cost-conscious end users will also look for efficiency improvements without major capital expenditure, looking for ways to revamp the existing plant in order to achieve the desired level of particulate matter (PM) emissions in a reliable and cost-effective way. This can involve improving the performance of existing electrostatic precipitators (ESP).

Avanti Environmental Group is one of the latest resource specialists to transform waste into fuel for the cement industry. Global Cement found out more about the manufacturing process at this new, state-of-the-art facility in Merseyside, UK.

US-based SpecFuel Partners LLC has been recognised by the US Environmental Protection Agency for the creation of a high-specification engineered ‘non-waste’ alternative fuel, called SpecFuel, for the cement industry. The company now has bold plans to build a number of SpecFuel preparation plants around the US to serve the cement industry.