Skip to main content

Want to compete? Recover your heat.

Published by , Editor
World Cement,


Marco Rovetta, CTP Team, offers an analysis of how much heat can be recovered from a cement line and the impact that waste heat recovery (WHR) can have on the sustainability of the cement industry.

One of the primary environmental issues for the cement industry is the control of dust emissions, however every technology that is designed to control emissions is also a cause of secondary CO2 emissions through its energy consumption.

As a result, even if air pollution control (APC) systems do the important work of limiting industrial emissions according to environmental regulations, they still interfere to some extent with today’s commitment to prevent climate change. Since there are no suitable low-carbon, industrial emissions control technologies to replace the existing infrastructure today, all cement producers must play their part. The path to reducing these CO2 emissions starts with the optimisation of equipment and processes to improve their energy efficiency; this is not just reducing consumption by replacing old and obsolete pieces of equipment with new ones, but also extending such energy saving initiatives to the underlying process.

In this vein, cement producers can continue identifying the possible uses for waste heat, which can be reused in the process as it is or for producing electrical power through a suitable Rankine cycle technology.

The cement industry is already on the road to carbon neutrality with the adoption of carbon looping technologies in the production process or by using calcined clay. New technologies will be released in the future, but systems and procedures aimed at optimising emissions control equipment, as well as for equipment involved in the production process, are already available. Moreover, waste heat recovery (WHR) is now a reliable solution for reusing the heat no longer suitable for production.

Optimisation of energy consumption

Figure 1 shows the potential impact that the operation of emissions control equipment has on secondary CO2 emissions, as well as the possible savings that can be reached through optimising existing equipment.

The figure also shows the estimated energy consumption of a burning line of 4000 tpd (for study purposes only; real cases may differ). The energy spent on operating process bag filters at 15 mbar DP, can be estimated at about 10.4 million kWh/y, with a potential saving of 2.0 million kWh/y when reducing the DP from 30 mbar. The CO2 savings related to this change are in the range of 0.65 tpy.

Applying the same concept to nuisance bag filters, the total power consumption is estimated at about 1.6 million kWh/y and a potential saving of 0.3 million kWh/y, saving 0.96 tpy CO2.

If a high dust DeNOx system is installed, the impact is an estimated 1.5 million kWh/y increase in power consumption.


Enjoyed what you've read so far? Finish the article and access the entire December issue of World Cement by registering, free of charge, here.

Read the article online at: https://www.worldcement.com/special-reports/16122022/want-to-compete-recover-your-heat/

You might also like

 
 

Embed article link: (copy the HTML code below):