By Anke Henrich
Florian Festge feels fortunate to be working a stone's throw away from a stunning natural environment. Whichever way the business economist, who manages with his brother the machinery affairs of Haver & Boecker in Oelde, looks of out his office window: The meadows, fields and forests of the Münsterland region are less than 2,000 meters away. Festge as well his uncle and cousin, who are responsible for the company's wire weaving divisions, feel not only this habitat is well worth protecting. That is why, as a supplier to the cement industry, Haver & Boecker is designing new processes to reduce CO2 emissions during the packing and palletizing process.
Concret: Most used substance in industry
It is urgently needed. If cement production were a country, it would have the third highest CO2 emissions after China and the USA. Cement is needed to produce concrete - the world's most used substance in industry, after water. Because concrete is so cheap, hard and flexible, annual global production of cement has risen from 1 billion to more than 4 billion metric tons over the last 30 years - which means around 2.8 billion metric tons of carbon dioxide.
This is largely due to the calcium oxide required. It is extracted from limestone, which mainly consists of calcium carbonate (CaCO3). Burning it releases CO2 and leaves the calcium oxide (CaO) behind. Around 45 percent of cement emissions are due to the fact that production requires temperatures of up to 1,400 °C, while 55 percent are process emissions. Founded in 1887, the family company Haver & Boecker has always been designing innovative solutions for packaging, storage, logistics and mineral processing technology.
"Our technologies can reduce CO2 emissions by reducing the energy input in production and by decreasing the losses that occur during production, filling, storage, transport and processing," says Festge. "It is not only good for the climate but also for the humans working in the cement production process. Significantly cutting dust emissions in the packing house, is a huge step toward the health and safety of all operators."
Production uses a huge amount of energy in raw meal milling, the firing process and clinker milling. Packing also requires energy. Dust removal systems required to return cement lost during filling to the cycle, lead to relatively high-energy consumption by running at full power regardless of output, even during brief shutdown times on the packing system. Haver & Boecker - employing 2,950 people - is trying a different approach: "A combination of automated bag placement, filling and sealing increases the throughput compared to manual, unsealed output.", says Festge and adds: "This allows us to increase the efficiency significantly, especially in Asia and Africa." The secret lies in the optimum coordination of product, bags and filling technology during the packaging process. The performance, cleanliness and weight accuracy of existing systems can be controlled more precisely with a plant optimization plan and retrofitting measures.
Many packaging machines, for example, which are designed for 2,400 bags per hour in nominal capacity, are usually only performing at rates of 1,900 bags or 95 metric tons per hour. "By optimizing the process together with our customers, we can increase the performance to 2,200 sacks or 110 metric tons per hour. This is a production rate increase of more than 15 percent".
Product losses are also a major issue. Up to ten percent of bagged cement can be lost during filling and on the way to the customer. Central cone silos for bulk goods, new, clean filling, dust-free dosing and tear-resistant packaging that is protected against humidity can all reduce waste. Haver & Boecker has designed a new, tight packaging system, which fills cement into recyclable PE bags and can reduce that rate down to one percent.
Process optimization is one way to save CO2 - chemistry is another. Clinker substitutes such as fly ash are increasingly popular. But experts warn "Because they often come from coal-fired power stations, their potential for the future may have its limitations. Also, changing the composition of the cement results in different product behavior." Cement with a higher clinker substitute content usually has to be milled more finely to give it the same quality characteristics as cement made from 100 percent fired limestone. It is also a bigger challenge to fill.
But there are other ideas - replacing limestone with carbon-free magnesium silicate, for example. This actually extracts CO2 from the atmosphere during the production of cement. Another suggestion comes from the Massachusetts Institute of Technology (MIT), where researchers have placed calcium carbonate in an electrolysis cell instead of heating it. There, water is split into oxygen and hydrogen, while added calcium carbonate is converted into calcium hydroxide, which is used in cement production. Practical application is still a long way off, however.
How realistic is it to replace fossil fuels with alternatives?
In Europe, some manufacturers have already succeeded in replacing almost 100 percent of their fuel. But the lowest share is where most of global production takes place - in Asia and Africa. Festge knows why: "When the recycling loop is not complete, there is no waste to act as a replacement fuel. We need to look at how waste can be collected and treated there, so that it can serve as a replacement fuel." He believes that plastic is not only harmless, but is a true value-add material, which provides additional benefits when recycled, reused or utilized as an source of energy. That is why Haver & Boecker is working on payback systems for PE and other bags.
The mechanical engineering industry cannot solve the problem alone. "We need an optimized waste and valuable materials concept," advocates Festge. It could pay off twice over. Countries with sustainable economies also invest in jobs and higher social standards. But cement producers have also benefited from the search for alternatives in production, he says. "If you treat waste materials and convert them into new, valuable resources, you can diversify your product range and find totally new fields of use."