Innovation

Cement production is a very energy-intensive process. It takes 100-115 kg of standard coal to produce one ton of cement clinker, which is a semi-finished cement product after the raw materials (mainly limestone, clay and iron), in proper proportions, are burned to partial or complete melting and cooled. Producing cement also consumes a lot of electricity (about 90 ~ 115kWh per ton of cement) and produces a great amount of heat. A cement rotary kiln is the primary piece of equipment in the production line of cement clinker. In the forging and firing process of cement clinker, the waste heat of the low-temperature exhaust gas (below 400 C) discharged by the kiln end preheater and the clinker cooler at the kiln head accounts for more than 30% of the total heat consumption of cement clinker and is a serious waste of energy. By applying the waste heat power generation technology, the waste heat of the low-temperature exhaust gas can be converted into electricity and can be reused in the production process, yielding a 60% reduction in total electricity consumption. Moreover, this innovation has been sold to other cement companies, which has supported the carbon neutrality efforts of the whole cement industry. Other companies only need to pay for the equipment and the installation services offered by the joint venture, and there is no requirement for worker training.

Carbon capture, utilization and storage (CCUS) is the process of separating carbon dioxide (CO₂) from industrial or other emission sources and transporting it to a specific location for use or storage in order to achieve long-term isolation of captured CO₂ from the atmosphere. The CO₂ storage and utilization technology mainly uses chemical materials to collect and store CO₂ at the end of gas emission, which can further purify the collected CO₂ and make industrial or edible products, generating commercial value.

In 2018, through the cooperation with Dalian University of Technology, Conch successfully implemented a 50,000-ton CO₂ capture, collection and purification project in its Baima Mountain Cement Plant. And this project became the first carbon capture application project of the cement industry around the world. The capture process of the project can be briefly described as follows: flue gas from the cement kiln is captured, then transported to a desulfurization washing tower, absorption tower, stripping tower, and refining sulfur bed. Transporting to these locations achieves various objectives, such as the removal of impurities and purification. Finally the gas is stored in tanks as liquid. The project can simultaneously produce 30,000 tons of 99.9% pure industrial-grade CO₂ and 20,000 tons of 99.9% pure food-grade CO₂. The products can be widely used in beverage production, vegetable preservation, dry ice production and other fields. This project has obtained 23 independent patents. Furthermore, the China Science and Technology Enterprise Development Evaluation Center and China Building Materials Federation have recognized this technology to be of a world-leading level.

The CO₂ Capture and Purification Equipments

Inspiration

"Energy conservation and emission reduction is the only way for our country to achieve sustainable development. As one of the top cement manufacturers in China, our company must set a good example in the industry and develop sustainable development technology that is not only suitable for itself but also can be promoted in the industry," said Mr. Chen, who is the head of safety operation of Conch.

"A large amount of heat is produced during the production of cement. It is inevitable," said Mr. Chen. But the company's engineers realized that if the waste heat could be used effectively, it could improve the efficiency of energy use and reduce production costs. "Then we tried to use the waste heat from the tail of the cement kiln to generate electricity by referring to the process of thermal power generation," explained Mr. Chen.

Company leaders also realized that they had to make an effort to find ways to reduce the company's carbon footprint. "In recent years, our country has been emphasizing the concept of "carbon neutrality", and our technology is also based on this concept, which is in response to the call of our government. Since our cement production process will produce a large amount of CO₂, how to deal with and use this carbon is a key point for us when considering the sustainable development of Conch." This led to the launch of Conch's carbon capture, collection and purification project.

Overall impact

The world-leading cogeneration technology developed by Conch can reduce the electricity consumption of cement production by 60% and save nearly CNY 1 billion yuan of electricity cost every year. Furthermore, the cogeneration technology used in Conch can save about 1.4 million tons of raw coal and reduce the emission of CO₂ by approximately 3 million tons per year. Besides, the products of its carbon capture and utilization technologies can be widely used in many fields, such as industrial and food production. Additionally, the research and innovation behind these projects have produced 23 independent patents in total and have been recognized as world-class by leading Chinese science organization.

Business benefit

Thanks to promotion efforts by Conch, a cogeneration system has been included in the construction standards of cement plants in China. Conch plays a leading role in cogeneration, driving the whole industry to save energy and reduce consumption. After the purification process, the CO₂ can be used in industrial process, such as industrial welding and fire extinguishers, and food production, for instance, as raw material in the making of beer and carbonated beverages, and in food preservation (e.g., dry ice). Through these products, Conch’s innovation has produced additional downstream benefits.

Social and environmental benefit

All these efforts play an important role in reducing Conch’s carbon footprint and making it a reliable and responsible company. From the perspective of cogeneration, it avoids the waste of energy, and it also reduces the emission of greenhouse gases which are contained in the waste heat. The cogeneration technology can greatly reduce the purchase of electricity from power plants, or power generation through its own power plants, which greatly reduce energy consumption and the emission of combustion wastes such as CO₂ from fuel consumption. This technology is contributing to SDG 7 (Affordable and Clean Energy) and 12 (Sustainable Consumption and Production).

From the perspective of carbon capture and carbon utilization, Conch has become a leader in cogeneration. Its innovations could lead to breakthroughs in overcoming two current bottlenecks in carbon capture and carbon utilization. The first is the extremely high cost of current technologies, which has made commercialization difficult. The second is the heretofore limited market for carbon products. As Conch is a leader in its industry, it can expand the carbon products market by achieving economies of scale, which will attract other companies. This aligns with SDG 12 (Sustainable Consumption and Production). Since CO₂ is a major contributor to global warming, which in turn contributes to climate change, Conch’s innovations in carbon capturing and carbon utilizing can help achieve SDG 13 (Climate Action). One of the advantages of the technological innovations developed by Conch is that they are designed to be sold to other companies, making them highly scalable. Given the size of the cement industry, and the intensity of large-scale construction, in China, the potential for impact is considerable. If it were to sell or license these technologies to companies in other countries, Conch could make a real difference in humanity’s quest to become carbon neutral.

Interview

Mingxiu CHEN, Head of safety operation