In recent years, under the target of "double carbon", the contraction of market demand and the pressure of cost, the pace of energy-saving and carbon-reducing technological transformation of cement enterprises has been accelerated. The implementation of energy-saving and carbon-reducing technological transformation in enterprises can not only reduce production costs, improve the competitiveness of enterprises, but also achieve the goal of energy-saving and consumption-reducing, which can be said to kill two birds with one stone. Oxygen-enriched combustion is one of the technologies that help enterprises save energy, reduce carbon, increase production and increase efficiency.
Oxygen-enriched combustion is not a new technology, which has been used for many years in foreign countries and other industries. However, considering the investment in technical transformation of oxygen generation system, the cost of oxygen generation and the energy-saving effect of oxygen-enriched combustion, this technology has not been widely used in the cement industry. Chen Changcheng, deputy general manager and chief engineer of
Hangzhou Haida Machinery Equipment Co., Ltd. (Hereinafter referred to as "Haida Company"), pointed out that the energy-saving effect of oxygen-enriched combustion is the key to investment efficiency and payback period. The key of oxygen-enriched combustion technology is oxygen production technology + combustion technology, and the embodiment of energy-saving benefits lies in combustion technology. There are many factors involved in how to play the role of oxygen-enriched combustion in cement kiln in cement calcination, such as the calorific value of coal and related components, the change of batching scheme, the adaptability and adjustment of burner, the operation adjustment of cooler, the flow and pressure adjustment of primary air, etc. Different cement kilns need in-depth exploration of kiln operation to find the best energy-saving point. Oxygen-enriched combustion can be widely used and promoted only when it achieves a certain energy-saving effect, so that the energy-saving benefit is more than production cost + financial cost + depreciation of fixed assets.
Chen Changcheng introduced that Haida Company adopted positive pressure membrane oxygen-enriched technology to carry out oxygen-enriched combustion-supporting technology transformation, which is mature and reliable in technology, moderate in investment, low in operation and maintenance cost, simpl e in operation and obvious in energy-saving effect, and can significantly reduce energy consumption and carbon emissions in cement production process. Improve the quality of clinker and reduce the production cost of enterprises. In addition to the use of oxygen-enriched products for combustion-supporting, the by-product of
positive pressure membrane oxygen-enriched combustion technology, nitrogen-rich gas, is still used in cement production as compressed air. In addition, by optimizing the combustion process, the energy utilization efficiency is improved and unnecessary energy waste is reduced. The application of this technology not only reduces the carbon emissions in the cement production process, but also brings significant economic benefits to enterprises, and further enhances the competitiveness of enterprises.
It is understood that Haida Company was founded in 2003 and has been deeply engaged in the field of compressed air purification, design, production and energy-saving renovation for more than 20 years. In 2021, it began to focus on the application of oxygen-enriched combustion technology in cement, glass, ceramics, refractories, boilers and other industries. The core of the positive pressure membrane oxygen production technology mastered by Haida Company is that different gases in compressed air have different permeability through the positive pressure membrane. Driven by pressure difference, oxygen is preferentially permeated and enriched, thus producing oxygen-enriched air with 35% -45% oxygen content. The oxygen enrichment technology of positive pressure membrane oxygen production is highly praised by industrial developed countries and is praised as "creative technology of resources" because of its advantages such as extremely low power consumption of oxygen production (only 0.07 Kwh per cubic meter, power consumption per ton of clinker is less than 1.5k wh/TCL), long life of membrane group, stable and reliable operation, simple operation and remarkable energy-saving effect.
Chen Changcheng introduced that the oxygen-enriched energy-saving project of Haida Company's cement enterprise has been applied to a base of Southern Cement , a central enterprise. During the implementation of the project, Haida Company adheres to the principle of "minimum intervention and maximum benefit". On the basis of not changing the original compressed air pipeline system and production process, an additional oxygen-enriched oxygen generation system is built.
This design strategy not only improves the flexibility and reliability of the system, but also ensures that when the oxygen-enriched system encounters any failure, the compressed air supply system can quickly switch back to the original gas transmission system and production process, and the kiln head combustion can also be switched back to the atmosphere at any time to support combustion, thus maintaining the stability and reliability of production.
The project only took more than three months from the signing of the contract to the commissioning of the system. During the subsequent commissioning of the oxygen-enriched combustion-supporting system, the energy-saving effect of the system, the product quality and the increase of power consumption of the system were gradually verified. After the oxygen-enriched combustion system is put into operation, the strength of clinker increases by ≥ 0.5 Mpa in 3 days and ≥ 2 Mpa in 28 days, the power consumption of the system per ton of clinker increases by ≤ 1.5 kwh/TCL, and the standard coal is saved by ≥ Above 4 kg/TCL, the output of clinker is increased. The positive pressure oxygen generation membrane selected by the oxygen enrichment technology equipment
of Haida Company is imported from South Korea. The service life of the membrane is 8-10 years, and the longest can even reach 15 years. The oxygen generation efficiency of the membrane will not be attenuated to 95% within half a year, and the oxygen generation efficiency of 95% will be maintained continuously. Chen Changcheng said that in the future, Haida will continue to deepen the research and development of membrane oxygen enrichment technology and system optimization, bring tangible energy saving and carbon reduction benefits to more cement enterprises, and help the green transformation of the industry.
