Cost saving transition from oil to pulverised coal in cement making

Requirements for a pulverised fuels plant

A complex process like the transition from oil to pulverised fuels requires top project management skills and first-class equipment suppliers. A team of four highly qualified engineers led by Mr. Radwan Mouakat, the head of the project department at National Cement, ensured the project was completed on site over a period of four months. All suppliers delivered the equipment on time to the site and an experienced local company carried out the building and steel construction work. In May 2012, the new coal plant was commissioned and the flame, fed by pulverised fuels, was ignited. 

Installed equipment

The coal mill has a maximum capacity of 40 t/h and the fine coal storage silo has a design volume of 230 t. National Cement’s weighing and dosing equipment of choice was the patented Pfister® rotor weighfeeder designed and built by the German engineers from FLSmidth Pfister. The rotor weighfeeder type rotor weighfeeder Pfister® DRW feeds 17.8 pulverised fuels per hour into the main burner over a feed distance of 139 m, and 16.2 t/h to the calciner burner over a feed distance of 90 m. With its state-of-theart prospective control ProsCon®, Pfister rotor weighfeeders fulfil the high requirements for stable fuel dosing with high short and long-term accuracy and ensure outstanding flame stability. The metering system at National Cement is an ATEX execution.

A FLSmidth Douflex® burner fires the rotary kiln and calciner with the pulverized coal, which produces a narrow and radiant flame that provides good heat transfer from the flame to the material in the sintering zone of the kiln. The burner is able to maintain a constant high momentum with a strong flame, which ensures complete combustion and keeps the formation of carbon monoxide and nitrogen oxides to a minimum. The burner has a thermal capacity of 102 MW. 

Successful transition

 Precise fuel metering of the firing process is essential for stable kiln operation and cost-effective process control. With rotor weighfeeder Pfister® DRW, the FLSmidth Douflex® burner and FLSmidth’s engineering know-how, National Cement is now firing the kiln with pulverised coal as an alternative to oil. And with a high and immediate return on investment the transition has been a great success.