1. Overview of China's economic development in 2022
In 2022, in the face of multiple unexpected factors, China effectively coordinated epidemic prevention and control and economic and social development, and maintained overall economic and social stability; Over the past three years, China's gross domestic product (GDP) has grown at a compound annual rate of 4.5%, one of the highest among major economies in the world. In 2022, China's economy will face the triple pressure of shrinking demand, supply shock and weakening expectations, and industrial economic growth will fall to a lower level than before the epidemic.
2. The development of lime related industries
(1) Steel, alumina, calcium carbide three major lime demand industry output has increased ①steel: In the past ten years, the wave of cross-regional and cross-ownership mergers and acquisitions in the iron and steel industry has swept the country, especially the strategic restructuring that continues to accelerate on the basis of specialization, aiming at reducing homogenized competition and characterized by asset transfer, and has built a new industrial pattern dominated by "Nanbaowu and North Angang Steel". After the reorganization of Qingdao Iron and Steel, Valin Tin Steel, Zhejiang Steel Pipe and Tianjin Steel Pipe, CITIC Pacific Special Steel Group has an annual steel production capacity of more than 14 million tons, becoming the largest and most comprehensive specialized special steel production enterprise in the world, and becoming a truly global special steel leading enterprise.
China Iron and Steel Industry Association data show that the proportion of crude steel production of China's top 10 steel enterprises in the country increased from 35.9% in 2016 to 41.5% in 2021, but the overall level is still at a low level, lower than the United States, Japan, South Korea and so on. In the first three quarters of 2022, the steel industry is in trouble again, and the price is deeply lowered. From January to September, the national crude steel consumption fell by 4%, but there are differences between various varieties, the demand for threads fell by 15.8%, the demand for hot rolling fell by 4.3%, the demand for cold rolling fell by 2.4%, the demand for medium and thick plates increased by 1.6%, the demand for long materials declined, and the demand for plates increased or decreased, reflecting that the economic structure is actively adjusting.
The statistics of crude steel production from 2017 to 2022 are shown in Table 2. It is expected that the cost of steel raw materials in 2023 will show a downward trend compared with the previous year, the average price of iron ore index will remain at about $85, down 26%, and the average price of coal coke index will remain at about 1600 yuan/ton, down 30%. Overall steel prices fell first and then rose, with an average annual price decline of 15%. According to the statistical data in 2021: China's pig iron production is 868.568 million tons, calculated by the consumption of 85kg lime per ton of iron, the annual amount of sintered lime is 73.82828 million tons. In 2021, the output of crude steel will be 1.03105 billion tons, and the annual consumption of lime for steel making will be 39.18 million tons based on the consumption of lime (including refining) by 38kg per ton of steel. Metallurgical lime market capacity in 2021 is 113 million tons. Steel demand in 2023 is expected to be flat compared with 2022, with crude steel production of about 1.02 billion tons, and total lime demand is expected to be about 111.9 million tons.
②Alumina: In the first half of 2022, domestic alumina supply is generally abundant, and new production can concentrate on a large number of releases. As of the end of May, the domestic alumina built capacity of 94.17 million tons, an increase of 5.2% from the end of December last year, the operating capacity of 82.4 million tons, an increase of 12.3% from the end of December last year, the alumina operating rate of 87.5%. Affected by a substantial increase in production capacity, alumina prices fell sharply in the first half of the year after the Winter Olympics limited production and the summer epidemic.
③Calcium carbide: The downstream of the domestic calcium carbide industry is mainly concentrated in PVC production, and the apparent consumption of calcium carbide in the past five years is about 27 million tons/year. PVC demand is growing steadily, and it is conservatively expected that PVC demand for calcium carbide will maintain a compound growth of 3% in the next five years. BDO is driven by degradable plastic PBAT, is expected to maintain rapid growth, currently operating, under construction and planning and has carried out preliminary work of the BDO project as many as 220, by the end of 2029 is expected to produce more than 17.5 million tons. It is predicted that the calcium carbide route BDO will consume 4.2 million tons of calcium carbide per year by 2025. Assuming that other demand for calcium carbide remains unchanged, the domestic demand for calcium carbide in the next few years is estimated to be about 27 million tons in 2022, about 31.5 million tons in 2023, and domestic calcium carbide consumption is about 33.85 million tons in 2025. The lime demand of the above three industries in 2022 is about 155.12 million tons, which is basically the same as the previous year. Affected by the macro economy, these industries are in a state of low profit or loss, plus coal and other fuel prices are high, the lime industry as a whole is in a state of low profit, no supporting limestone mining enterprises are in a difficult situation, many enterprises limit production, or even stop production.
二、Construction of rotary kiln
Up to now, there are about 580 lime and dolomite rotary kilns that have been built and put into operation in China. According to the preliminary statistics of the backbone enterprises of the Lime Association, about 25 lime rotary kilns are expected to start construction in 2022, with a production capacity of about 8 million tons after being put into operation, and the new production capacity accounts for a relatively high proportion of all kiln types.
三、Development trend of rotary kiln technology
1.Promote the large-scale of rotary kiln, reduce energy consumption lime kiln large-scale is an effective means to reduce fuel and power consumption. According to incomplete domestic statistics, the rotary kiln above 800t/d saves about 10% energy compared with the rotary kiln below 600t/d. Therefore, it is recommended to promote the rotary kiln production line above 800t/d according to the market situation.
2.The application of biomass energy and other alternative fuels many large lime multinational companies in the world are actively developing alternative fuels, such as waste fuel, hydrogen energy, biomass fuel, etc., the current proportion of alternative fuel use more than 20%, in order to significantly reduce the carbon emissions of energy combustion process. Lime rotary kiln production line fuel adaptability, such as the production line near the waste fuel, biomass fuel is rich, according to the characteristics of resources, choose the appropriate alternative fuel utilization, partial or full replacement of conventional fuel, reduce the use of conventional fuel, reduce carbon emissions.
3. After the application of oxygen-enriched combustion technology, the fuel is burned more fully, the smoke volume is reduced, and the heat generated by the unit fuel is greatly increased, which is conducive to saving fuel resources. However, it is necessary to solve the problem of how to control the increase of nitrogen oxides in the exhaust gas and the air volume for lime cooling. The solution is: oxygen enrichment, reduce the amount of air, reasonable introduction of kiln tail gas, increase the concentration of CO2 in the exhaust gas, CO2 resource utilization. However, its process route equipment investment is huge, and it needs to be implemented until the industrial chain is economically reasonable, such as carbon trading prices rise to a reasonable price, or application in the plateau hypoxic area.
4.The development of energy-saving technology, energy-saving host and the use of energy-saving equipment, improve the energy-saving level of the production line continuous optimization of the production line process route, the host such as preheater, rotary kiln, cooler energy saving and efficiency improvement, fan, motor using high-efficiency products, can further reduce the energy consumption level of the production line.
5The use of intelligent control to stabilize the overall energy consumption level of the same equipment, different operators and management levels, energy consumption indicators vary. Improving the intelligent level of the production line, especially the use of intelligent combustion control system, can reduce the influence of human factors and stabilize the energy consumption level of the production line.
6.Research and development and promotion of low-temperature waste heat efficient utilization technology due to differences in calcining methods, rotary kiln and advanced kiln heat consumption is high, such as the rational use of kiln tail gas and kiln skin waste heat, will overcome the disadvantage of high energy consumption of rotary kiln, and reduce the overall energy consumption of the industrial chain, ultra-low emissions and denitrification is an example of the disadvantage of rotary kiln change advantages.
7.Promote the industrial application of carbon dioxide capture, utilization and storage technology without considering fuel and electricity, each ton of lime calcination can produce 0.78 tons of CO2. The lime industry is a large CO2 emission, reasonable design process, kiln tail gas can produce high concentration of CO2, according to the different regions, should choose a reasonable use of CO2 resources, such as industrial and food CO2, production of baking soda, salicylic acid, etc., to reduce greenhouse gas emissions.
