Mannok Cement embarks on its project to reduce its carbon footprint
During the final commissioning of the FUELFLEX® Pyrolyzer at the Mannok Cement plant in Ireland in 2022, the ambitious cement manufacturer was keen to embark on the next steps of its Vision 2030 project to reduce its carbon footprint.
”The FUELFLEX enables us to burn up to 100% alternative fuels in the calciner while also bringing NOx emissions right down. It’s been a game-changer for our plant,” explains Damian Reilly, Mannok Cement. “The next obvious step for us was to upgrade our coal dosing system so that we can reduce the amount of coal going into the preheater to an absolute minimum without sacrificing flexibility. We were happy to continue working with FLSmidth on these projects, knowing we share similar goals.”
Traditionally, coal feeders have operated with a minimum quantity of 1 tph of coal. This is low relative to the quantity of alternative fuels being fired, but still higher than many plants would like at a time where every carbon saving counts. However, eliminating coal from cement production entirely is not on the cards right now.
“The ambition to remove coal from the pyroprocess was what drove us to develop a more flexible coal feeder,” says Peter Norek, Global Product Manager Feeding and Dosing Technologies, FLSmidth. “Even with the ability to fire 100% alternative fuels, most plants still require the ‘fallback’ of coal for when SRF supplies are low, or at start-up. The Pfister® FEEDflex is basically an upgrade to the proven and widely used Pfister® DRW Rotor Weighfeeder, with the advantage of a much lower minimum feed rate – down to as little as 60 kg/h – with no change to the maximum feed rate. The achievable feed range of 1:100 means that plants can significantly reduce their coal usage, without hamstringing their operation if greater quantities of fuel are required.”
The FEEDflex has been available for 5 years and was part of Mannok Cement’s plans for the plant since the early stages of the FUELFLEX development in 2019. The plant was already operating two SRF lines to the calciner using Pfister TRW-S feeders, but the minimum coal feed quantity was not yet a limitation, as it became when the FUELFLEX came into operation. Now one SRF line feeds via the FUELFLEX and one directly into the calciner. Before the FEEDflex upgrade, their existing coal feeders were fixed at a minimum feed rate of 1 tph. However, with the new SRF capacity in the calciner, the plant wanted to reduce this to 0.16 tph.
“This has been a multi-way project,” explains Damian. “On the one hand, we’re bringing in a new feeder upgrade to reduce the quantity of coal. On the other, we’ve optimised our TRW-S feeders to increase their SRF capacity and make the most of the FUELFLEX. And then the third part of the project is the ECS/ProcessExpert® advanced process control software, which has been remarkable.”
Reducing coal feed
The FEEDflex technology consists of newly designed air distribution in the DRW Rotor Weighfeeder by replacing and adding parts, which allows significantly lower rotor rpm without leading in pulsations. The upgrade can be easily carried out in just one day during regular maintenance shutdown.
