Cement is a highly energy intensive industry, with production on the increase to meet demand and over 4.3 gt of cement produced globally in 2020. As governments focus on reducing emissions, cement plant owners are seeking alternative fuels (AFR), new processes and additives as a means of reducing their environmental impact. This approach brings new industry challenges. The increased use of AFR can lead to dangerous pockets of incomplete combustion within a kiln and an increase of vaporized volatile gases leading to an increased risk of explosion and costly kiln stoppage.
Image Credit: ABB Cement Solutions
ABB has developed ProKiln, a gas sampling system, to meet these challenges head on, offering permanent and uninterrupted process control in cement rotary kilns. The new cement kiln inlet gas system features powerful probe cleaning with increased mechanical strength, which includes a dual probe retraction system unique to the market to ensure no sampling interruption.
One of the main issues facing kiln operators when gathering data is the scaling of material both on a probe’s surface and in the sample intake area, as well as material falling in through the riser duct. The ProKiln gets round the problem with an extractive filter in the tip of the probe which separates sample gas from the dust load. In addition, the ProKiln’s patented technology uses two air blasters to clean the tip of the probe maintaining a sample path for critical analysis even under extreme conditions.
A 3D printed stainless steel nozzle ensures that no blockages at the tip of the probe occur and the system is mounted on a buggy running on a retractor which carries the probe safely in and out of the kiln allowing it to be cleaned automatically. Measuring three meters long, the gas probe is water cooled with an extractive filter placed at the sample and flow is maintained by the blasters. A cooling system provides recirculating water for temperature control, essential in operating conditions where process gases can reach 1200 °C (2200 °F).
ProKiln has been put through its paces during a trial at Holcim, the world’s largest cement producer. The test ran for 6 months at their Lägerdorf plant that uses more than 80 percent alternative fuels. The reduced maintenance efforts and the increased availability convinced the customer to replace the current installation with ProKiln.