Taking pyroprocessing to the next level

Cemtech hosted its March webinar on advanced pyroprocessing and kiln control technologies this week, which provided a glimpse into the future of the carbon-neutral kiln, alongside presentations on high-temperature kiln monitoring and refractory solutions for sustainable goals.

The full Advanced pyroprocessing and kiln control technologies March webinar can be watched on this link.

The sun sets on cement production
Davide Zampini, head of R&D at Cemex, and Dr Gianluca Ambrosetti, CEO of Synhelion, spoke about the future of pyroprocessing with the solar kiln and the need to reduce CO₂ emissions in kiln operations. "Cement is a CO₂ intensive with 40 per cent of CO₂ coming from the combustion of fossil fuels and 60 per cent due to the calcination process" said Mr Zampini.

This project aims to reduce, concentrate and capture CO₂ emissions and reutilise it. Innovative technologies like this will account for 48 per cent of the cement sector’s pathway to lower CO₂ emissions by 2050. Concentrated solar thermal heat can offer costs as low as one euro cent/KWh_th. Absorbed greenhouse gases are heated by the thermal radiation of the Synhelion solar receiver walls and act as a heat transfer fluid heating up to above 1500˚C. The receiver also fills up the thermal energy storage (TES) unit so that during the night the kiln can run off the TES.

The 2021 target is to have a calcination lab pilot 250kWt_h unit, followed by a calcination pilot plant producing 1MW_th in 2023, and full integration by 2026 with a 10MWth plant. Hopefully, this will lead to an industrial-scale plant of 100MW_th producing 600tpd of cement by 2028. Captured CO₂ will be used to make syngas (H₂ +CO) and gasoline, diesel, jet fuel and methanol. 

Temperature checking
John Window, Mirion Technologies' business development and strategy director, highlighted its M555^® High temperature Spyrometer™ camera technology that targets reliable and consistent process control, and provides real-time data as part of a fully-automated process control system. Process control benefits include optimisation of the burning zone for the highest clinker quality, reduction of CO₂ and NO_x as well as reduction in operating costs through the use of alternative fuels, pre-warning for uneven product flow and burner and refractory management.

The Spyrometer™ provides consistent and highly-accurate temperature measurement in modern dry-process kilns, claimed John Window. Linked to a DCS (expert system) the camera can provide a return on investment in six months through fuel and energy savings and improved kiln stability. Accurate monitoring can also be achieved with alternative fuels with a potential for a further five per cent savings. The Spyrometer uses patented dual-wavelength technology to maintain temperature accuracy in dusty kiln conditions, two detectors can be used and each of the 32 temperature measurement zones (TMZ) can be independently adjusted.

The Slimline M215 S Spyrometer™ dual processor allows connection of two pyrometers for the cooler and kiln monitoring, remote diagnosis, on-screen and stored trending capabilities and video zoom. In addition, the Spyrometer™ cooler camera avoids snowman formation, maximises heat recovery and has a large range of oblique-angle lenses.

Current developments include upgrading Spyrometer™ to HD, improving the graphical user interface to include automatic storage temperature for the 32 TMZs, TMZs shown on trending display, user selection of the range of the trending displayed and multiple spot selection of any point on a trending graph.

Jérôme Duez and Catherine Barrat of HGH Systems talked about complete kiln shell temperature monitoring using the company's Pyroscan and Kilnscan 23 technology. Pyroscan monitors the burner process, while Kilnscan is equipped with a 23-line scanner with real-time surveillance and alarms for hot spots on the kiln shell and kiln tyre slippage. It uses a two-scanner configuration for long wet kilns. Shadows are eliminated thanks to multiple scanner configuration and multiple images. At Tasek Cement in Malaysia, for example, three scanners were used, but up to eight ‘shadow pyrometers’ can be employed for the elimination of small shadow areas. Kilnscan also has a unique 140˚ extended scan angle to analyse the full kiln shell even inside a building.

Refractory technology for sustainability
Michael Louen, technical director of Cement and Lime Europe at Calderys Deutshchland, and Claude Lefévre, technical support at Calderys France, spoke on the UniverCEM^® refractory for improved sustainability. Cement plant challenges include production in the most cost-effective way, mitigating health and safety risks and risks to the environment. Calderys' UniverCEM^® refractory has high-alkali resistance and combines the mechanical and chemical properties of lower content of cement (LCC) and low cement castable refractory products. It can be applied by dry-gunning or by casting. It is suitable for areas with high abrasion, thermal shock and high-alkali loads. UniverCEM^® has five product lines and is a durable refractory with low-porosity and low-calcium aluminate cement. UniverCEM^® offers less downtime due to more installation speed, fewer different materials on site, longer lining lifetime and one material for both casting or dry-gunning installation methods.