[click to enlarge] Lafarge's G2-based LUCIE applies expert judgement to cement kiln control.

Lafarge, the world leader in building materials, is also the number one cement producer in the world. The company operates in 75 countries and employs over 75,000 people.

In 1989, Lafarge started to research different means of improving the profitability of its cement-making business. Finding an answer would not be easy because of the complexity of the production process. Producing cement is much like baking a cake. In order to produce the optimum batch of cement at the lowest cost, certain ingredients are required in specific amounts. These ingredients must then be mixed in a specific manner in the plant's raw feed mill and heated at exact temperatures in the pre-heaters and rotary kiln. Gypsum and other ingredients are then added to the cement mixture. If the ingredients are mixed too little or too long, or if the temperature is too low or high in the rotary kiln, the resulting batch may have imperfections. It also may have been more expensive to produce than necessary. Lafarge engineers knew that if they could intelligently monitor cement production, they could use the perfect recipe for production each time by reducing the variability in the process and optimizing production. Lafarge turned to Gensym. Lucie, a G2-based solution, was the result.

Lucie is Lafarge's answer to automating kilns, grate coolers and mills. Its use has expanded to over 40 cement kilns worldwide throughout the last decade. Kiln automation is achieved by employing fuzzy logic, process modeling and statistical auto-adaptation of key parameters. Expert knowledge of the cement-making process is built into the system using rules. Gensym's neural network techniques and rule-based reasoning engine have judged the process conditions in the plant's raw feed mill, pre-heaters, rotary kiln and cement mill for over 12 years. If conditions are not optimum, Lucie applies short-term and long-term actions to make sure that the cement mixture is always produced in perfect fashion.

[click to enlarge] LUCIE operator screen graphically displays process conditions and assessments.

Lucie is a work in progress thanks to the flexibility and efficiency of the G2 platform. Lafarge engineers and experts at the kilns continue to expand upon its capabilities. Latest developments include more statistical and graphical ways to diagnose and optimize key parameters. A built-in fuel manager now improves stability and performance by managing the secondary fuels used in kilns.

Lucie's intelligent monitoring and reasoning capabilities help Lafarge produce uniform, quality products at an optimum production rate. Additionally, the solution helps to optimize energy consumption during the cement-making process and monitors the emission of NOx, a harmful by-product gas. The widespread application of G2-based Lucie has provided a common technical culture among the worldwide plants of Lafarge, and Lucie has established that a common operating philosophy can be successful at any Lafarge facility.