2014 June12 June 1 1:48 source: China environment news.
China is one of the contracting parties to the Minamata Convention. According to the Convention, the parties will ban the production, import and export of mercury-added products by 2020. Mercury chloride is used as a catalyst in the production of PVC by calcium carbide method, which is the industry with the largest amount of mercury in China.
How to adjust the production structure of PVC in China under the pressure of fulfilling international conventions? What are the difficulties in clean production of PVC? To this end, the reporter interviewed Jianying, a senior technician of Qilu Branch of Sinopec.
◆ Our trainee reporter Li Xianyi
What are the performance difficulties?
The Convention will force the transformation and upgrading of the industry, and it is imperative to guide qualified calcium carbide enterprises to turn to ethylene method. When the production and sales of calcium carbide PVC decrease, the total mercury consumption will decrease.
Reporter: China has signed the Minamata Convention. What impact will this have on the PVC industry in China?
Fu Jianying: China is the largest producer, user and emitter of mercury in the world. 20 12 data shows that the national mercury output reaches 1347 tons, and the amount of mercury discharged into the atmosphere every year is 500 ~ 700 tons, which poses a serious threat to the environment and health. Therefore, even if there is no international convention on mercury restrictions, it is necessary to increase mercury restrictions from the perspective of protecting our own environment.
The production of PVC in China is mainly based on calcium carbide method, which uses mercury chloride as catalyst, and is the industry with the largest mercury consumption, accounting for 60% of the total consumption in China. Up to now, the production capacity and sales volume of PVC by calcium carbide method in China account for more than 80% of the whole industry, and there is a further upward trend.
The signing of the international mercury convention will greatly restrict the development of PVC by calcium carbide method, force the transformation and upgrading of PVC industry, and take the road of clean production, which is conducive to the long-term healthy development of the industry, while PVC by ethylene method will win development opportunities.
Reporter: What are the difficulties in limiting mercury in China at present? How to adjust the development of PVC industry?
Fu Jianying: The mainstream view in PVC industry is that China is limited by resources rich in coal, poor in oil and poor in gas, so calcium carbide method should be the main method. This has led to serious deviation in the development direction of PVC industry in China in recent years. Although ethylene PVC is internationally recognized as clean production, it has absolute advantages in environmental protection and product quality compared with calcium carbide PVC with high energy consumption and high pollution. However, in the face of low cost and high benefit of calcium carbide PVC, this advantage has been ignored by the industry.
According to the actual output of the current calcium carbide process, even if all low-mercury catalysts are used before 2020, the annual mercury consumption will reach 500 ~ 600 tons. Moreover, at present, the domestic production of PVC by calcium carbide method continues to increase, and it is expected that the consumption of mercury will also increase.
In 20 14, the national new PVC production capacity was 3.23 million tons, and calcium carbide method accounted for the vast majority. According to this development, even if the low mercury catalyst technology is fully adopted by 2020, the total amount of mercury used in PVC by calcium carbide method in China will not decrease much, and the harm to the environment is still huge.
At present, the government of China has put forward "three noes" requirements for the prevention and control of mercury pollution: First, the replacement cycle of high-mercury catalysts is not relaxed, and relevant enterprises should quickly formulate replacement plans to ensure that all low-mercury catalysts must be used to replace high-mercury catalysts in 20 15 years; Second, the requirements for prevention and control of mercury pollution are not relaxed, and the industry should strengthen self-discipline and take various measures to strengthen prevention and control; Third, the supervision of the Ministry of Environmental Protection on the prevention and control of mercury pollution is not soft, and enterprises that fail to meet the standards must be resolutely ordered to rectify.
Therefore, I personally think that there will be some poor performance or unexecutable PVC production capacity of calcium carbide method in the future. In terms of policy, it is also necessary to appropriately limit the calcium carbide method and speed up the market withdrawal, such as raising electricity prices and increasing carbon emission charges.
At the same time, we should support the development of ethylene process, improve the competitiveness of PVC through ethylene process, and then increase its market share. The urgent task is to guide and encourage some qualified calcium carbide enterprises to turn to ethylene route, and gradually increase the proportion of production and sales of PVC by ethylene method. When the production and sales of PVC by calcium carbide method decrease, the total mercury consumption will decrease, which will greatly alleviate the pressure of mercury restriction and pave the way for a total ban on mercury.
The proportion of calcium carbide PVC is serious, which has caused great harm to the environment. Even if the mercury-free PVC technology is realized by calcium carbide method, it still cannot get rid of the problems of high energy consumption and high pollution. Therefore, reducing the production and sales of PVC by calcium carbide method is not only beneficial to the limitation of mercury, but also the need of energy saving and emission reduction.
The promotion of low mercury catalyst is slow.
China requires the popularization rate of low-mercury catalysts to reach 50%, but the current ratio is only about 20%.
Reporter: How about the promotion of low mercury catalyst in China? What are the problems and difficulties?
Fu Jianying: The promotion of low mercury catalyst in China is relatively slow. On the one hand, there are still many problems in low-mercury catalyst itself and enterprise application technology, and it will take time to solve them thoroughly. On the other hand, the application of low-mercury catalyst needs all-round support from technology, capital and production equipment.
The Convention clearly requires that by 2020, the mercury consumption per unit of PVC production will be reduced by 50% compared with 20 10. For calcium carbide PVC, the application ratio of low mercury catalyst technology is not high, and high mercury catalyst is still dominant, which is also the difficulty of China's performance.
In recent years, relevant departments in China have also introduced a series of measures and methods to promote the clean production of PVC industry.
In 2009, China Petroleum and Chemical Industry Association, China Chlor-alkali Industry Association and China Chemical Environmental Protection Association drafted the Guiding Opinions on Strengthening the Prevention and Control of Mercury Pollution in PVC Industry.
On June 4th, 20 10, the Ministry of Industry and Information Technology issued the Notice on Printing and Distributing the Comprehensive Prevention and Control Plan for Mercury Pollution in PVC Industry by Calcium Carbide Method, which required that by 20 12, the popularization rate of low-mercury catalyst in PVC industry by calcium carbide method in China would reach 50%, the average mercury chloride consumption per ton of PVC would decrease by 25%, and the waste mercury catalyst in the whole industry would be reasonably recovered. The penetration rate of hydrochloric acid deep desorption technology reached more than 90% to 20 15 years, and all low-mercury catalysts were used in the whole industry. The consumption of mercury chloride per ton of PVC was reduced by 50%, and the recovery rate of waste low-mercury catalysts reached 100%.
However, although most PVC enterprises with calcium carbide process have made substitution plans for low-mercury catalysts, and the proportion of their use has gradually increased, up to now, the overall application proportion of low-mercury catalysts is only about 20%, which is still far from the above goals. At present, there are no official statistics on the recovery rate of waste low-mercury catalyst and the penetration rate of hydrochloric acid deep desorption technology.
Reporter: How do enterprises know about low-mercury catalysts? What are the actual cases?
Fu Jianying: The understanding and practice of applying low mercury catalyst in PVC industry by calcium carbide method are also deepening. Especially since last year, key chlor-alkali enterprises such as Xinjiang Tianye, Shandong Xinlong, Yibin Tianyuan, Zhongtai Chemical and Hebei Shenghua have actively participated in the research and development and production of low-mercury catalysts, greatly improving the market supply capacity of low-mercury catalysts.
Among them, Xinjiang Tianye million tons of PVC devices have all achieved low mercury, reducing mercury consumption by 70 tons every year, and actively providing other enterprises with comprehensive solutions for mercury pollution prevention and control; A large number of enterprises, such as Zhongtai Chemical, are accelerating the replacement application of low mercury catalyst 100%; Shandong Xinlong set up a technical service team for vinyl chloride synthesis and the use of low-mercury catalysts ... which effectively promoted the wide application of low-mercury catalysts.
However, most enterprises with different scales and poor strength are unable to promote low-mercury catalysts. It is almost impossible for these enterprises to achieve the goal of comprehensive prevention and control of mercury pollution in 20 15 years, and even it is not easy to achieve the goal of 2020 proposed by the Minamata Convention.
Mercury-free technology is still in the research and development stage.
Reducing the consumption of mercury is fundamental, and the production and sales of PVC by calcium carbide method must be controlled.
Reporter: Is the mercury-free technology of domestic PVC production mature at present?
Fu Jianying: The Minamata Convention also proposes to phase out chlor-alkali production using mercury in 2025. This means that by 2025, even low-mercury catalysts can no longer be used, and PVC enterprises with calcium carbide method must realize mercury-free production technology if they want to survive.
At present, it is very difficult to implement this provision. Although China has begun to develop mercury-free technology, it is only in the research and development stage, and there is still a long way to go before industrialization and comprehensive popularization and application. I think there is great uncertainty whether the mercury-free technology can be fully popularized and applied in 10.
In terms of mercury pollution control, China's technology and management are relatively backward, and the safeguard measures and supervision mechanisms such as laws, regulations and standard systems are still not perfect. In this case, reducing the total amount of mercury used is the most direct and effective way to reduce mercury pollution. Therefore, it is necessary to control the production and sales of PVC by calcium carbide method while reducing the mercury consumption per unit PVC output.
Reporter: Will the production of PVC by ethylene method have an impact on China's ethylene supply and demand market?
Fu Jianying: Because of its advantages in production mode, vinyl PVC will play an irreplaceable positive role in fulfilling the mercury convention and protecting the environment. At present, the annual production and sales of PVC in China is about130,000 tons. If all PVC is produced by ethylene method, 6.2 million tons of ethylene will be consumed. If 50% is produced by ethylene method, only 365,438+million tons of ethylene is needed. After deducting the original ethylene production capacity, the new ethylene demand is less than 2 million tons, which will not have much impact on China's ethylene supply and demand market with an annual demand of 47 million tons.
At the same time, the diversified pattern of ethylene production is gradually formed, which will support the production of PVC by ethylene method. Ethylene production no longer depends solely on oil. In recent years, great progress has been made in the production of ethylene from coal and natural gas. In 20 13, the production scale of olefin from coal in China was 2.73 million tons. The research results of Yahua Consulting, a professional research institution of coal-based energy and chemical industry, show that the production capacity of olefins from coal (methanol) will reach 23.65 million tons/year in 20 18.
The development of shale gas in North America will affect the global investment pattern of ethylene and its downstream derivatives in the future, and the production of PVC has more price advantages. With the increase of ethylene production in the United States, the international ethylene price will be greatly impacted.
■ Related links
The Minamata Convention was opened for signature in Minamata, Japan on June 65, 1965. This is a legally binding multilateral environmental treaty. The final content was agreed by governments in June 438+03, 1965. With the approval of 50 governments, according to the provisions of the Convention, the parties will ban the production, import and export of mercury-added products by 2020.
In the mid-20th century, many Japanese residents were poisoned after eating mercury-contaminated seafood in Minamata Bay. After the incident, in order to arouse people's attention to mercury pollution, the nervous system syndrome caused by severe mercury poisoning was called "Minamata disease".