Transcript 幻灯片 1
“Low Carbon” in the Iron and Steel Industry Low-carbon production: a production mode featuring low energy consumption, low waste and low emission and aiming at minimum GHG emission during production. Low-carbon consumption: minimum impact upon the environment (CO2 emission reduction) and maximum efficiency of resources utilization in the product lifecycle from placement to scrap processing to optimize both the economic and social benefits of a business. The iron & steel industry is typically resource and energy-intensive Resources: consume a lot of iron ores and ferroalloys to produce key raw materials (steel products), but discharge a lot of wastes at the same time. Energy: the “high-carbon” coals still remain the main primary energy for a long period in the future. Energy consumption can be reduced through more efficient use of energy by way of collecting various residue heat and pressure, which is also the main approach to reduce CO2 emission. In essence, low-carbon in the iron & steel industry means to achieve energy saving and emission reduction during production, reduce CO2 and other GHG emission remarkably and provide “green” iron & steel products so as to realize energy efficiency during the production and application processes. Therefore, energy-saving, emission reduction and production of long-life heavy-performing iron & steel goods will be the most efficient and effective measures for a low-carbon development of the iron & steel industry. Contents Ⅰ. Status quo of energy efficiency of the iron & steel industry Ⅱ. Measures taken by the industry to promote low-carbon development Ⅲ. Potentials and direction for low-carbon development of the industry Ⅰ. Status quo of energy efficiency of the iron & steel industry Ⅰ. Status quo of energy efficiency of the iron & steel industry 吨钢综合能耗 烧结 炼铁 焦化 调整工艺结构 ［淘汰落后］ 800 700 600 普及 推广 节能 环保 技术 500 400 300 200 100 0 2005年 2006年 2007年 2008年 2009年 2010年 2011年 加强节能环保 高效科学管理 The comprehensive energy consumption per ton steel has reduced significantly. The average energy consumption of the surveyed key enterprises dropped from 694.72 kg in 2005 to 601.72 kg standard coal in 2011. (equivalent coefficient is 0.1229) Less energy is consumed in some key procedures of iron and steel processing, if comparing the two figured between 2005 and 2011: a drop of energy consumption per ton from 440.6 kg to 404.22 kg standard coal for iron making, from 65.09 kg to 54.36 kg standard coal for sintering, and from 135.78 kg to 106.65 kg standard coal for coking. Ⅰ. Status quo of energy efficiency of the iron & steel industry 34% of energy produced by metallurgical coals will convert into byproduct gas, so good coal gas means higher energy efficiency. Therefore, the first thing to do is to produce none or less byproduct gas. During the 11th Five-Year Plan period, the utilization of coke oven gas, blast furnace gas and LDG is illustrated in the above chart. If comparing the two figures between 2005 and 2010, we could see an increase of the three gases collection respectively by 42.71%, 78.3% and 177%, or respectively 0.24, 2.98 and 2.04 percentage points higher than 2005 (LDG utilization per ton steel increased by 49 percentage points) . Ⅱ. Measures taken by the industry to promote low-carbon development 1. Promote the application of some sophisticated energy-saving technologies Since the 11th Five-Year Plan period, iron & steel businesses have applied some energy-saving technologies and facilities, achieving a great success. According to incomplete statistics, the coke dry quenching facilities installed in large and medium-sized businesses increased from 20 sets in 2005 to 154 sets in 2011, topping the world in terms of quantity and capacity, and the blast dry TRT also increased from 49 to 600 sets. In 2008 there were only 4 sets of power generation facilities with sintering residual heat, but now 87 sets of such equipment are placed for 150 sintering machines. And also, the CCPP unit increased from 6 to 36 sets in number from 2005 to 2011, generating a total of 3700MW power and annually consuming 50 billion m3 blast furnace gases with low heating value. In one word, recently the sophisticated energy-saving technologies have been used increasingly. As for the recovery of residue heat produced in production, some large enterprises have conducted research in sensible heat of coke-oven raw gas, sintering sensible heat, sensible heat recovery of blast furnace slag, and high added value of excess coal gas. some of the technologies, like metallurgical liquid slag sensible heat recovery for residential heating, LDG for methanol and blast furnace gas reuse, have been piloted on site and the preliminary results have been achieved. The sophisticated energy-efficient technologies applied during the 11th Five-Year Plan period No. Technology Performance CDQ 1t coke quenching can recover about 0.50 tons of 4.5 Mpa 450 ℃ (or 9.8Mpa 540 ℃) steam and reduce 95kgCO2/t coke. 2 Coal Moisture Control Coal charge moisture drops from 11% to 6%, i.e., 14 kgce saved per ton coke, 44 kg ammonia reduced per ton coal, less residue water containing phenol and cyanogen discharged, and 48kgCO2/t coking reduced. 3 Sintering Residue Heat 90 kg heat steam /t sinter ores recovered and 10kgCO2/t ores reduced. 4 TRT 30kWh/t generated, 54kWh recovered, and 19~38kgCO2/t iron reduced 5 LDG Recovery 80Nm3 coal gas /t recovered and 23kgce energy /t steel saved 6 LDG Sensible Heat Recovery 15kWh/t steel recovered and 14kgCO2/t steel reduced 7 Heating for Regenerative Rolling 18 kgce /t energy saved 1 Ⅱ. Measures taken by the industry to promote low-carbon development 2. The major processing equipment has improved significantly Generally speaking, a blast furnaces smaller than 300 m3 consumes more than 50kgce energy /t, higher than the average of 20kgce/t and much higher than the domestic advanced level of 200kgce/t; while a convert smaller than 20t may consume energy 10kgce/t higher than the average and 90kgce/t higher than the domestic advanced level. Comparing with the heavyperforming facilities, they consume 7%~10% more material, one time more water and 3 times more emissions. The outdated small sintering machine consumes 10~15% more energy and 7~10% more material per unit than the larger one, because the current sophisticated technologies like sintering residue heat for power generation and HRSG can hardly be applied in the outdated sintering machines (less than 90 m2 ). Recently, the key equipment in China has been greatly improved. The sintering machines larger than 130m2 in key large and medium-sized iron & steel enterprises totaled 232,an increase from 21.4% in 2005 to 48.9% in 2011; the blast furnaces larger than 1000m3 in the key enterprises totaled 241, increasing from 20.6% in 2005 to 40.6% in 2011; and the 100t+ converters totaled 262, rising from 26% in 2005 to 47.5% in 2011. Ⅱ. Measures taken by the industry to promote low-carbon development 3. The management is intensified to achieve energy efficiency In recent years, automation and control technology has been widely introduced to the iron & steel industry, particularly in the newly-built facilities; as a result, 80% of metal-smelting processes have been computerized. A non-stop, compact and efficient production mode has been established where the middle products engage in an on-going process during production and a single tank of molten iron instead of a metal mixer is used for steel making in order to keep the temperature and avoid iron loss, which may generate both energy efficiency and productivity. This production mode is being practiced at some newly-built steel bases including Shougang’s Jingtang Steel (Caofeidian), Ansteel’s Bayuquan and Chonggang’s New Area. By setting a EMS, the iron & steel businesses have the primary and secondary energies in each process centralized and automatized to ensure sustainable energy supply and energy efficiency. With EMS, the businesses not only can better use the secondary energy but the energy-producing facilities, resulting in significant increase of productivity and energy use as well as a stable 2% energy-saving rate. In the recent 2 years, with the government’s financial support, 55 businesses have established or are setting up EMSs, which are estimated to contribute 3.6 million tce energy-saving, an equivalent of 10.9 million tons CO2 reduced. Ⅲ. Potentials and direction for lowcarbon development of the industry 1. Outdate the non-efficient metallurgical processes and facilities 2. Improve energy efficiency and employ more non-carbon resources by leveraging on S&T progress 3. Focus on scraps reuse and gradually develop EAF 4. Extend steel mill’s functions to promote circular economy 5. Encourage use of high-performance steel and increase its operational efficiency 1. Outdate the non-efficient metallurgical processes and facilities Outdated and inefficient equipment is not suitable either for intensive production or for application of energy-saving measures to recover the secondary energy, resulting in much higher energy consumption than the large facilities. For instance, the outdated small sintering machine consumes 10~15% more energy and 7~10% more material per unit than the larger one, because the current sophisticated technologies like sintering residue heat for power generation and HRSG can hardly be applied in the outdated sintering machines (less than 90 m2 ). It is estimated that as the output reaches 750 million tons in 2015, an equivalent of 38 million ton standard coal energy will be saved comparing to 2010 and the comprehensive energy consumption per ton steel of the whole industry will drop by 18.8% from 2005 by way of replacing the obsolete with better production capacity and on condition of no more scrap consumption. This is a remarkable achievement for the energy efficiency of the iron & steel industry. 2. Improve energy efficiency and employ more non-carbon resources by leveraging on S&T progress Studies show that technological progress can contribute as much as 40~60% to energy-saving. Therefore, higher efficiency and narrower gap with the global level still rely on advanced technology and better innovative capability. The key to low-carbon economy is the application of energy-saving technologies. All the initiatives like improving the penetration rate of various sophisticated technologies, researching and disseminating new energy-saving measures and developing alternative energy resources will play an important role in energy efficiency, cost effectiveness and low-carbon emissions during the iron & steel production. By analyzing and estimating the outreaching potentials and outcomes of 22 energy-saving technologies used in the iron & steel industry, the ISA believes that as much as 33.8 million tce energy will be saved and 94.8 million ton CO2 will be reduced by 2015. Technology-for-efficiency can be achieved at three levels Tap into the potentials of sophisticated technologies Promote industrialization of new technologies Coal Moisture Control Develop and reserve leadingedge technologies Coke oven processing city Sintering Residue Heat for Sensible heat recovery of plastic or rubber power generation raw coke oven gas in Non-coking iron-making LDG Sensible Heat Recovery ascension pipe Ore alloying CCPP Slag sensible heat Strip casting CCPP frequency conversion recovery New energy use (wind potentials blast furnace gas reuse power, solar power, etc.) during 12th Five Year Electric furnace residue Converter blowing CO2 heat recovery Clean energy from heat recovery and metallurgical by-product gas condensed water CO2 separation and storage Large Plan period reutilization 3. Focus on scraps reuse and gradually develop EAF Since EAF mainly uses renewable resources—scraps—as material and electricity as energy source, it consumes less raw materials and produces less gases and wastes than the blast-converter furnace. As a result, it is more conducive to energy saving, pollution reduction and limited damage to the environment, and also can produce special steel products with high added value which cannot be made by converters. Currently, China’s crude steel produced by EAF remains a lower proportion compared to developed countries (in 2011 cast iron/crude steel was 92.1％ in China, 75.3％ in Japan, 61.7％ in South Korea and 62.8％ in Germany). Besides the market’s large demand for ordinary steel, another reason for that is the limited storage of scrap steel and short and expensive power supply result in higher cost of EAF production than the converter. In future, with increments of scrap steel, it is imperative for China to promote shortened process and provide supportive policies, making it an approach to addressing CO2 emissions in the iron & steel industry. 4. Extend steel mill’s functions to promote circular economy Cooperate with heat supply companies Collectively supply heat for the urban residents to make more use of the excess residue heat. Cooperate with the construction sector to promote comprehensive use of solid wastes like steel slag Cement can contain as much as 40% blast furnace slags, equivalent to 40% energy saved, which is a common practice in the industry. Steel slags, activated through grinding, can replace cement as building material to reduce the cracks caused by concrete hydrant heat and improve its long-term strength and abrasive resistance. Currently, the output of steel slag powder only accounts for 19% of the total slags produced. Therefore, during the 12th Five-Year Plan period, it’s necessary to promote use of steel slags in the cement industry and proprietary research in the application of slags in glass ceramics, mineral wool and other relevant areas, encourage utilization of steel slags as resources, and reduce consumption of raw resources in the downstream industries, so as to cause less CO2 emissions.。 Cooperate with the chemical industry to encourage the use of byproduct gases as resources Use of byproduct gases as resource may increase its added value and generate hydrogen, natural gas, methanol, dimethyl ether, etc. The approach to make hydrogen gas for the medium scale is mature, while the focus should be on how to better use blast and converter furnace gases that contain more carbon. Establish “collective fire” hybrid mode to achieve the goal of “zero emission” ”Collective firing” combines strengths of both the steel plant and power plant by leveraging on the former’s residue resources (byproduct gases) and the latter’s facilities (boilers and heavy generator set). Only by placing the gas transmission pipes and transforming the boilers, can the power be generated, which means that less investment generates more benefits. Therefore, the government should provide some incentives. Display the social functionalities of the iron & steel businesses As blast furnace or coke oven is used to digest the waste plastics, tires and medical plastics, the treated urban sewage water is reused in iron & steel businesses, and wastes produced by the alkaline and calcium carbide businesses are used instead of industrial lime to treat the non-ferrous chemical products containing Cr residue and red mud, all these initiatives are being made to reduce the use of raw fuels and to reuse the wastes as resources at the same time so as to display the social roles of the iron & steel industry. 5. Encourage use of high-performance steel and increase its operational efficiency Considering steel’s whole life cycle, the use of high-performing steel can increase its utility efficiency and the overall CO2 emission will be reduced although the production process may involve more CO2 production. Therefore, from a low-carbon-economy perspective, the iron & steel industry should adopt the key technologies featuring high efficiency, less consumption and low emission to provide the high-performing, long-life and environmentally-friendly products, such as high-performance silicon steel, automotive steel, construction steel, withering steel, etc., to minimize the use of raw resources and reduce steel consumption during the economic development, as a way to support energy-saving efforts of the other industries and promote low-carbon development cross the whole country. During the 12th Five-Year Plan period, the iron & steel industry will try to develop the new materials with higher performance, longer life and more environmental protection. Scientific steel-saving is the trend in future Constru Witherin Automo Stainles s Steel ction Steel g Steel tive Steel In 2009, the output of China’s hot rolled ribbed bars at 400MPa and more accounts for 31.8% of the total bars; if plus 30%-50% consumption of steel bars of Grade Ⅲ or higher, there will be 20%30%PC more consumed. These two categories can save as much as 15.3-24.5 million tons steel. Every year about 1/10 steel is corroded in the world, which means that the lost metal value accounts for 4% of the global total output value. So steel’s higher wear and corrosion resistance can mitigate the physical losses, elongate steel’s life cycle, and reduce its consumption within the lifecycle. If an automobile is 10% lighter, fuel efficiency can improve 6%-8%. The automotive body accounts for 30% of the total weight, which generally consumes 70% of fuel energy when a vehicle is unloaded. The use of high-performing auto sheet can lighten a vehicle and play a significant role in reducing oil consumption and tail gas emission. The energy-saving stainless steel developed through technological optimization not only can reduce consumption of over 40% nickel, 1-4% chromium and 1-2% molybdenum, but also can lessen the ferroalloy production scale and lower the dependence on the precious alloys of other countries. Electrica l Steel The performance of the silicon steel elements in the electromechanical equipment plays an important part in the use and conversion of electricity. Every year the power loss in the form of core heat accounts for 5% of total power generated. The iron loss of different varieties of electrical steel ranges 1-10W/kg; if conservatively estimated at an average of 4W/kg, more than 117 million kwh power has been lost every year. Adoption of the new electrical steel technology, even only 0.1 W/kg less iron loss is achieved, can save as much as tens of million kwh power every ten thousand ton non-oriented electrical steel each year. Thank you Department of Science and Environment Protection, China Iron & Steel Association September 2012