The domestic coke oven denitration market urgently needs technological breakthroughs – technological innovation must generate economic benefits for enterprises

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This post was last edited by angryant on 2016-8-2 at 19:30. According to Zheng Wenhua, a leading expert from the China Coking Industry Association, there are currently over 600 coking plants across the country, and last year the output of coke was 447.8 million tons. In recent years, the average concentration of NOx in the flue gas from coke ovens in domestic coking plants has been around 650 mg/Nm3. If these flue gases meet the **NOx emission standards for the coking industry (500 mg/Nm3 in ordinary areas and 150 mg/Nm3 in special areas), and assuming an average concentration of 450 mg/Nm3, approximately 265,000 tons of NOx can be reduced each year. This amounts to 1.9% of the total industrial NOx emissions in the country (according to the National Environmental Statistics Bulletin 2014, industrial NOx emissions totaled 14.048 million tons). 　　Based on this, some experts estimate that if all coke ovens in the coking industry were equipped with denitration devices at the current production capacity, the total market value would be around 20 billion yuan. 　　However, there are still weaknesses in governance technologies within the industry at present. It is understood that, with current technology, the processes for dust removal and desulfurization separately are relatively mature, enabling emissions to meet regulatory standards. The vast majority of coke ovens find it difficult to meet the new standards regarding nitrogen oxide (NOx) removal, and traditional denitration technologies can no longer satisfy market demands. 　　“At present, there is a large denitration market in China’s coking industry that remains to be developed. For domestic environmental protection companies, this represents both an opportunity and a challenge; they need to increase their investment in research and development and acquire advanced technologies in order to expand their market presence. ”Industry insiders say. 　　Traditional technologies are not suitable; technologies that meet the requirements need to be developed urgently. Traditional denitration technologies cannot satisfy the market demands for denitration in coke ovens. The temperature of coke oven flue gas before denitrification is generally between 180°C and 300°C, which is lower than the temperature requirements for denitrification under traditional technologies; the pollutant composition of coke oven flue gas differs from that in the coal power industry. Reporters have learned that flue gas denitrification technologies in the coal power industry are relatively mature at present, and the main processes can be roughly divided into three categories: dry method, semi-dry method, and wet method. Among them, dry processes include selective catalytic reduction (SCR) and non-selective catalytic reduction (SNCR), semi-dry processes include the activated carbon-based desulfurization and denitrification method, while wet processes include the ozone oxidation absorption method. 　　However, research and practical experience in the industry show that the aforementioned denitration technologies used in the coal-fired power sector are insufficient to meet the market demands for denitration in coke ovens, and cannot achieve efficient denitration in such ovens. There are mainly 3 reasons. Firstly, before denitrification, the temperature of coke oven flue gas is generally between 180°C and 300°C, while the temperature of coal-fired power plant flue gas before denitrification ranges from 300°C to 450°C. The temperature in coke oven flues does not meet the temperature requirements of traditional processes, which hinders the application of certain technical methods for denitrifying coke oven flue gas. 　　Secondly, the pollutant composition of coke oven flue gas differs from that of the coal power industry. In the flue gas from coal power plants, the SO2 level is high while the NOx level is low; whereas in coke oven flue gas, the NOx level is high and the SO2 level is low. It also contains components such as tar, hydrogen sulfide (H2S), carbon monoxide, methane, and free carbon. As a result, processes suitable for flue gas with high sulfur levels and low nitrogen levels, such as the activated carbon-based desulfurization and denitrification method, are difficult to apply in the coking industry. 　　Thirdly, the temperature inside the coke oven chimney must be maintained above 130°C (this is referred to in the coking industry as chimney thermal standby). In the event of a failure in the exhaust fan, this ensures that the coke oven chimney can still provide stable pressure conditions for the coking process, without affecting the overall production of the coke oven. As a result, the use of wet processes with excessively low exhaust temperatures is limited in the coking industry. 　　“Currently, more than 20 companies in China are developing technologies for desulfurization and denitrification of coke oven flue gas. They are conducting research to address the challenges faced by traditional denitrification techniques in the coke oven industry, in order to meet market demands and secure as large a share as possible of the market for coke oven denitrification solutions. ”Industry insiders explain that some of these companies are management firms established by coking enterprises, while others are third-party firms specialized in treating flue gases from coking ovens; each of them has its own advantages. 　　Led by enterprises, breaking through the limitations of traditional denitration technologies: These enterprises have jointly developed catalysts (additives) that, in combination with conventional vanadium-titanium-based catalysts, enable low-temperature denitration in coke ovens, while also facilitating the simultaneous treatment of flue gases. They are actively seeking to expand into larger market segments. \"At present, several domestic enterprises are working on overcoming the limitations of traditional denitration technologies in the coke oven industry, and have achieved varying degrees of progress in this regard.\" ”Zheng Wenhua explained that some companies are attempting to develop low-temperature denitration technologies suitable for flue gas temperatures in coke ovens ranging from 180°C to 300°C. For example, MCC Coking & Refractory (Dalian) Engineering Technology Company has developed the \"integrated technology and process for dry/semi-dry desulfurization + low-temperature denitrification and dust removal through thermal desorption,\" Beijing Shougang International Engineering Technology Company has developed the \"integrated technology for low-temperature catalytic denitrification + waste heat recovery + wet desulfurization and dust removal,\" and Chengdu Guohua Environmental Protection Technology Company has developed \"new catalytic desulfurization methods and low-temperature SCR denitrification technologies.\" 　　“Some of the aforementioned technical processes have been industrialized, enabling efficient and stable denitration in coke ovens, and the companies responsible for their development are actively seeking to enter the market. Some have entered the pilot production stage. ”Zheng Wenhua further explained that the technology developed by MCC Coking & Refractory has been put into industrial use, the technology of Beijing Shougang International Engineering Company has passed the pilot-scale testing phase, and the technology developed by Chengdu Guohua Environmental Protection Technology Company has also completed pilot-scale testing and is now awaiting industrialization. 　　It is reported that the coke oven desulfurization and denitrification technology developed by MCC Coking & Refractory was named one of the \"Top 10 Technical Highlights in the World Steel Industry\" for 2015 by World Metal Review, and it is regarded as a significant breakthrough in denitrification within the coking industry. In fact, the desulfurization and denitrification technologies developed by MCC Coking & Refractory can be applied not only to the treatment of coke ovens in the steel industry but also to meet the needs of independent coking plants. 　　Zheng Wenhua explained that MCC Jiaonai, in collaboration with relevant research institutions, has developed a catalyst formula containing special catalyst promoters (additives). This formula enables conventional vanadium-titanium-based catalysts to maintain their activity, selectivity, and stability even at flue gas temperatures of 180°C to 300°C in coke ovens; such catalysts are less prone to poisoning and can achieve efficient nitrogen oxide removal. 　　“The device we developed achieves simultaneous desulfurization, dust removal, and denitration of coke oven flue gas. At present, coke oven flue gas purification has been implemented in various projects such as Baosteel Zhanjiang Iron and Steel Coke Plant and Shandong TieXiong Xinsha Coke Plant, achieving industrialization. ” Yin Hua, a professor-level senior engineer from MCC Coking & Refractory, explained. 　　“However, the aforementioned management enterprises still need to make greater efforts in areas such as technology commercialization and the dissemination of achievements, in order to promote the development of the coke oven denitration industry. ”Industry insiders say. Background information: The “ice age” in the market requires policy incentives to foster its healthy development. It is recommended to implement environmental protection subsidies and adopt various approaches to promote new technologies. “Some companies, under economic pressure, do not consider quality during bidding processes but instead seek the lowest price to win bids, which results in many inferior technologies and equipment entering the environmental protection sector.” ” Yin Hua, a professor-level senior engineer from MCC Coking & Refractory, has encountered many such cases while working to expand the market. The desulfurization and denitrification projects carried out by some small companies not only feature unreliable processes but also use shoddy equipment; these systems have to be dismantled after a short period of operation due to severe equipment corrosion, resulting in significant waste. 　　“In the past two years, affected by the downturn in upstream and downstream industries such as the steel industry, the profit margins of coking enterprises have declined significantly compared to before. Many property owners are willing to respond to the call and install environmental protection facilities, but they face excessive financial pressures; it is difficult for them to raise the funds needed for pollution control, and constructing desulfurization and denitration systems poses challenges. ”Industry experts believe. 　　To this end, Yin Hua stated that given the low amount of by-products generated in the desulfurization and denitrification processes of coke ovens, coking enterprises incur high economic costs when installing and operating environmental protection facilities with little return. He suggested that **it would be advisable to adopt measures similar to those used in the power industry, namely implementing environmental protection subsidy policies: rewarding positive behavior rather than punishing negative one, or ensuring clear distinctions between rewards and punishments. Help companies that are truly committed to reducing emissions get through the \"ice age\" in the coking industry, enable more enterprises to adopt mature and efficient technologies, and at the same time stimulate market vitality to foster healthy market development. 　　“Engineering companies should also offer a variety of cooperation models for owners to choose from, helping them acquire mature technologies while reducing investment costs. ”Yin Hua explained that, taking the desulfurization and denitrification project in Guizhou’s Qiangui Tianeng as an example, the local authorities **place great emphasis on and provide strong support for enterprises’ clean production practices. After thorough evaluations, CMCC Coking & Refractory was selected as the service provider for this project through a bidding process. The project adopts the EPC (Engineering, Procurement, and Construction) model, which not only allows for greater discounts on the total cost but also enables coking enterprises to focus on daily operations without having to devote too much effort to the construction process. At present, this project is under intense construction. “Apart from the EPC model, the EP model is undoubtedly a more cost-effective choice for owners with construction capabilities. ”Yin Hua further explained that in addition to the aforementioned traditional cooperation models, the BOT (Build-Operate-Transfer) model, which has emerged in recent years, is also a good approach for addressing urgent needs and reducing the financial pressure on owners and contractors.