We were able to achieve interesting savings in a cement production facility. Rotary kilns operate in this type of plants, while the burners are often a central tube introduced into the furnace. Optimization of the operation of such burners can bring significant reductions in energy consumption.
n the audited company, solid fuels (alternative and coal dust) were introduced into the furnace by means of wires. Light fuel oil is used to burn the burner - it is injected separately into the combustion chamber in the form of a mist. The burner also contained annular wires for introducing fresh air. Directional air ducts are used to form a suitable flame shape in the chamber.
For each furnace, there are several blowers supplying primary air of the temperature of approximately 20-25 Celsius degrees. Air supply pipelines are not insulated.
Based on own experience with other installations of this type, the Auditor proposed to modernize this system by increasing the temperature of the air supplied to the burner, with hot waste air used at the same time.
A number of investments were required for this optimization. They were mainly related to the adaptability of existing equipment, i.e. blowers or fans.
Considering the use of high temperatures, it was reasonable to provide thermal insulation to all components of the pipeline which transport hot air to the burners.
With reference to this modernization, the reduction in energy consumption of about 139.7 GWh was achieved, which in consequence resulted in savings of USD 1 million, with investment expenditures of USD 1.9 million.