Declare war on haze

　　The urgent need for "permanent cure"

　　Since the winter of 2012, the word "haze" has appeared in China's public vision. Haze has increasingly become an important topic in Chinese daily life, a shadow that seriously affects the quality of life and health of Chinese people, and a negative factor affecting China's economic development. Therefore, the government attaches great importance to haze and other air pollution control, and has invested a lot of money and energy, determined to bring the blue sky back. According to the 2016 government work report, it is necessary to crack down on air pollution, haze and water pollution. Subsequently, local governments have issued a large number of supporting policies and carried out a series of targeted projects. In the same year, the chemical oxygen demand and ammonia nitrogen emissions decreased by 2%, sulfur dioxide and nitrogen oxide emissions decreased by 3% respectively, and the concentration of fine particulate matter (PM2.5) in key areas continued to decline. Under the simultaneous development of a number of measures, the concentration of pollutants in China's key regions has been improved to some extent, but the results are not optimistic, and the haze has not been solved from the root.

　　How to control the haze and how to carry out the prevention and control of air pollution? Tracing back to the source, controlling the emission of pollutants from the source and comprehensive treatment at the end are the fundamental measures for the prevention and control of air pollution.

　　The way to cure haze begins with one step

　　This has to start with the source of the haze. Haze mainly comes from the emission of industrial flue gas by burning fossil fuels such as coal, petroleum as well as natural gas in thermal power, steel, smelting, cement, ceramics, glass, chemical industry and waste incineration industries. These flue gases or exhaust gases contain a large amount of dust (including PM particles, such as PM100, PM10, PM2.5, etc.), sulfur dioxide, sulfur trioxygenate, nitrogen oxide, hydrogen chloride, hydrogen fluoride and other highly toxic acid gases, and also contain organic substances of ammonia, dioxin, polycyclic aromatic hydrocarbons, VOCs and heavy metals. Therefore, from the perspective of the feasibility of pollution source control and industrial treatment, dust removal, desulfurization, denitrification, ammonia removal (amine) and organic matter removal (including VOCs) are the main means of haze control. At present, the requirements to pollution enterprises in China are mainly dust removal, desulfurization and denitrification treatment.

　　It is estimated that in 2016, the new investment in dust removal is about 50 billion yuan, desulfurization investment is 21 billion yuan, and denitrification investment is 84 billion yuan, totaling about 155 billion yuan. According to 43958 billion kwh of thermal power generation in 2016 and 0.027 yuan per kilowatt hour of electricity environmental protection subsidy (enforced by the power industry), the expenditure reached about 118.6 billion yuan. If you add in subsidies and investments from other industries and localities, the numbers are even more amazing.

    In these industries, most enterprises have taken dust removal, desulfurization and denitrification treatment for their flue gas or waste gas. However, most of them adopt electrostatic precipitator and bag filter for dust removal, limestone or ammonia desulfurization, SCR and SNCR denitrification. These traditional methods do not have the ability to remove organic materials of dioxins, polycyclic aromatic hydrocarbons and VOCs, etc. When the content of sulfur dioxide, nitrogen oxide, ammonia, dioxin, polycyclic aromatic hydrocarbons and VOCs in the air reach a certain concentration, atmospheric photochemical reaction will occur under the action of ultraviolet light. A large number of aerosols will be produced, and serious secondary haze will appear rapidly. The primary haze caused by the emission of micro particles is relatively serious. Due to the secondary haze, the haze will increase largely in a short time. In Beijing, this happens all the time.

　　The traditional technology of dust removal, desulfurization and denitration is not complete, and in some aspects, it can aggravate the formation of haze, which is why the haze control frequently encounters a wall under the condition of large continuous yearly investment. In addition, due to the high operating costs of traditional dust removal, desulfurization and denitrification processes, some enterprises only need to cope with the inspection of environmental protection equipment, and do not do it if they can. Of course, in addition to the factors of inadequate investment, more is due to the constraints of technical bottlenecks.

　　Facing the increasingly serious haze, is it a temporary cure or a permanent cure? The shutdown of enterprises seriously affects economic development and enterprise survival. Factory relocation does not reduce haze emissions. Coal to oil increases environmental consumption and increases energy costs. Strengthening monitoring, policy guidance and severe punishment can not fundamentally reduce haze. The key to solve the problem is to make a substantial breakthrough in flue gas treatment technology, overcome the defects of existing flue gas purification technology, and eliminate the emission of haze from the source.

　　DDS dedusting, desulfurization and denitrification technology for flue gas subverts the tradition

　　In April 2016, at the International Invention Exhibition in Geneva, the DDS dedusting, desulfurization and denitrification technology for flue gas invented by Dr. Xionghui Wei, doctoral supervisor of Peking University, won a special gold award. This technology is also unique in the world, and has applied for an international patent (PCT), and has obtained the invention patent authorization of the United States, Japan, Eurasia, Canada, Mexico and other countries. What kind of technology is this?

　　DDS dedusting, desulfurization and denitrification technology for flue gas adopts the method of full circulation of solution: after absorbing harmful components in flue gas, DDS dedusting agent, DDS desulfurization solution, or denitrification solution, is regenerated to release harmful components (which can be enriched as chemical raw materials). After regeneration, DDS dedusting agent, DDS desulfurization, or denitrification solution, is recycled to absorption. So absorption and regeneration is in a continuous recycling way.

　　In this process, limestone or lime is not used as desulfurizer, and the equipment site is clean and tidy; neither ammonia nor urea is used as denitrifier, so serious secondary pollution caused by ammonia escape is avoided.

　　What's more surprising is that DDS dedusting agent, DDS desulfurizer and DDS denitrifier are non-toxic and harmless, and will not cause secondary pollution to the environment. This technology can make SO₂ and NOx removed from the waste gas being converted into pure liquid SO₂ and nitrate products, realizing the transformation of waste into treasure. As the technology can "eat sulfur and drink nitrate", enterprises can remove the previous restrictions on high sulfur raw coal, heavy oil, coal tar and petroleum coke and other inferior fuels. The inferior fuel that could not be used effectively can produce more by-products with higher added value for enterprises, which is helpful for enterprises to change their energy structure and further reduce their operating costs.

　　Continuous development of technological innovation

　　Demonstrating trend of haze control

　　At present, DDS dedusting, desulfurization and denitrification technology for flue gas has been out of the laboratory, and has been successfully applied in pilot test at the end of 2013 and actual industrial test in the beginning of 2015, and has officially entered the stage of industrial application.

　　In 2015, a one-year small-scale industrial test was carried out in Baogang Group, and Baogang Group carried out tracking and monitoring on small-scale industrial devices. According to the monitoring results, the content of dust (including PM100, PM10, PM2.5, etc.) in flue gas treated by this technology can be reduced to less than 5mg/nm³, and can not be detected in most cases. The content of SO₂ can be reduced to less than 30mg/nm³, and can not be detected in most cases. The content of NOx can be reduced to below 35mg/nm³, and can not be detected in most cases. The results are far lower than the current national standard. At the same time, HCl, HF, dioxin, PAHs and other organic compounds (including some VOCs) and heavy metals can also be effectively removed.

　　Baotou municipal government, Baogang Group and technology owner decided to jointly build the demonstration project of this technology. At present, the demonstration project has been completed in the thermal power plant of Baogang Group, and is being put into use. The demonstration project has also been highly concerned by relevant departments and many units.

　　It is reported that the world's leading technology has been widely concerned and applied. If the technology is rapidly promoted and applied, the flue gas pollution problems of thermal power, steel, smelting, cement, ceramics, glass, chemical industry and waste incineration industries will be effectively controlled, and the "APEC blue" will remain forever. In this way, the green cycle and low-carbon development mode of low-cost, zero cost environmental protection investment and even profit-making in environmental protection, which has been vigorously advocated by the state for a long time, will become possible. It will greatly promote the enthusiasm and initiative of enterprises in the treatment of waste gas, and the haze problem is expected to be reduced or even eliminated in a relatively short period of time.