Electrostatic dust is still the mainstream of the future

What is the future development trend of electric dust removal?

Is still the mainstream technology, but the proportion will decline, not a kind of soot and dust control technology that the technology will require in the world? Guo Fahuahua, deputy director of the State Power Research Institute of Environmental Protection, said: "First, technology must be able to meet long-term and stable discharge standards. , And can adapt to coal quality fluctuations. Second, it is economic, but also want to run the horse but also want to not eat grass horses, in fact, is to conduct a comprehensive comparison."

Electrostatic dedusting has always been the dominant position in dust removal from coal-fired power plants in China. However, a few years ago, after the newly revised "Emission Standard for Air Pollutants from Thermal Power Plants" was published, the limit of 30 mg/m3 of soot emissions once allowed the electrostatic precipitator technology to be questioned.

For the future, Zhu Fahua believes that “the ratio of electrostatic precipitator will be reduced compared with the original, but it is still the mainstream technology.” The decline in the proportion is due to the difficulties of site reorganization in some old factories, and it is not possible to increase dust by increasing the electric field. Efficiency requires electric bag or bag dust removal. However, because the equipment is stable and reliable, electrostatic precipitator is still the mainstream technology.

Zhu Fahua jokingly stated that the electric iron dust girl like “Agriculture Learns Dazhai” was able to endure hardships and was very capable. Bag dusting was a bit like a delicate young lady, and it was tiring to go home to wait. “Because it is solid, it has determined that the requirements of the operation and management of the electrostatic precipitator are not very high and there are few equipment problems. However, serving the bag is a systematic project. For example, to control the temperature of the smoke, not only the people who care for the bag should pay attention to it, but never the coal or the boiler. Everyone in the entire process, such as air precipitators and economizers, must focus on control. This is a systematic project that requires everyone to work together to ensure their operation."

“There is still market space for electrostatic precipitators, and technology is constantly evolving. However, electric bags and bags are also developing. These three types of technologies are coexistence relations, not a technology package, all technologies have their own characteristics, advantages, etc. It is the relationship of mutual promotion and common development.” Huang Wei, general manager of Fujian Longjing Environmental Protection Co., Ltd. said that nowadays, all technologies are flourishing, and each technology is innovating and developing. We can't stand still and must advance with the times, according to the new Requires improvement. "Competition will promote technological advancement, cost reduction, and better meet user needs and environmental protection needs."

How to effectively promote new technologies?

Supported by advanced foreign technologies, the research and development work has been stable and stable. The electric dust removal industry has made remarkable achievements in technological innovation in recent years. A series of new technologies and new processes have achieved good results in practice. For example, wet-type electrostatic precipitators can meet higher emission requirements in certain areas, achieve comprehensive control of multiple pollutants, and are the last gated equipment for power plant dust control; low- and low-temperature electrostatic precipitators can serve multiple purposes at one and the same time. The four advantages of water and sulfur trioxide removal are not only beneficial to emission reduction, but also prevent the low-temperature corrosion of tail facilities.

Shu Yinggang said that the high initial investment cost has hindered the development of some new technologies to a certain extent. For example, the investment cost of a single electric field of a wet electrostatic precipitator is equivalent to the investment cost of 3~4 electric fields of a conventional electrostatic precipitator.

For power plants, is there any risk in adopting new technologies? In fact, many new technologies are only relative and new technologies for China. However, they have had many years of application history abroad and the technology is very mature. Domestic enterprises can use foreign mature technologies and experience to actively promote their application in China's coal-fired power plants.

For example, the wet electrostatic precipitator technology has been widely used in Europe, the United States, Japan, etc. and it has achieved good results. After the introduction of Japan's Mitsubishi Heavy Industries' horizontal smoke stream wet-type electrostatic precipitator technology, Fidelity Environmental Protection combined with the actual conditions of China's coal-fired power plants undertook an innovative development and developed a vertical wet gas flow and WFGD integrated wet-type electrostatic precipitator.

“The power plant has a high reliability requirement, especially for the coal quality that is facing complex changes in the country, and the promotion of new technologies must be more meticulous,” said senior expert Meng Dian of electric dust for the power industry. He believes that, first, companies are developing new technologies. The target requirements are high and must be consistent with the international advanced level; secondly, R&D should go through small tests, engineering pilots, small unit reliability tests, large unit tests, etc. It is not sufficient to have small test data, and the R&D road needs to be further Walk down solidly; again, theoretical research must be in place.

“The new technology must have theoretical support. For example, traditional theory holds that low temperature corrosion does not occur only when the smoke temperature is above the acid dew point, and low-temperature electric dust removal requires the facility to operate below the acid dew point. To allow the owner to believe that there must be new The theory to support interpretation, so that users believe that this process." According to Meng Hao introduced, in order to promote low-temperature electrostatic technology, Long Jing held a technical exchange meeting in Ningde Power Plant, allowing users to see the effect of emission reduction and operation .

How to use coal more cleanly?

Emissions from coal-fired units can be reduced to 5mg/m3. The development of such coal-electricity technologies at the national level should significantly reduce the impact of coal-fired pollution on the quality of the atmospheric environment. However, China's coal-based energy structure is difficult to change within a short period of time, and can it be cleaner? Land use coal? Huang Wei said that the cleaner use of coal can be done. The key is to be willing to invest in environmental protection. It is not whether there is pollution, but whether it can cure pollution.

With the development of new technologies and new technologies such as mobile electrode electrostatic dedusting, low-temperature electric dedusting, wet electrostatic dedusting, dust agglomeration, and new high-voltage power supply, more and more applications are being made in China. Now, the smoke from coal-fired power plants meets the emission standards of gas-fired power plants. The request is no longer a luxury.

In January of this year, the wet electrostatic precipitator of the 2×12MW unit of Shanghai Changxing Island No. 2 Power Plant was successfully put into operation. The on-site test results showed that the outlet dust concentration was 6.1 mg/m 3 . Shenhua Guohua Zhoushan Electric 1×350MW unit and Taizhou No. 2 power plant 2×1000MW unit will also adopt wet electrostatic precipitator technology. The project requires that the chimney outlet dust concentration is 5mg/m3. These values ​​have approached or met the emission requirements of natural gas turbine generator sets.

Zhu Fahua told reporters that the goal of the state-owned Taizhou Phase 2 project under construction is to meet the emission standards of gas-fired power plants. This project is supported by a series of advanced environmental protection measures, such as the installation of a cryogenic economizer, a six-field electrostatic precipitator and a high-frequency power supply, and a wet electrostatic precipitator after wet desulfurization to ensure final contamination. The emission concentration of the material can meet the requirements of the gas unit emission standards, and the unit energy consumption of the power plant will also drop to the lowest level in the world.

According to Zhu Fahua, this is a trend of development. "From the perspective of the characteristics of China's energy resources and energy security, we should encourage the development of such coal and electricity technologies at the national level." However, the environmental investment in this project accounts for 26% of the total project investment, which is also the highest in the country. The environmental protection investment of domestic power plants generally accounts for about 10%, and it rarely exceeds 15%. "There is investment in output, environmental protection investment, and output is the improvement of environmental quality." Zhu Fahua said.

In April 2012, the Shanghai Wujing Thermal Power Plant #9 furnace 300 MW unit dust aggregating device was put into operation. The PM2.5 concentration reduction rate of the electrostatic precipitator was 30.1%. After calculation, the PM2.5 emission reduction amounted to about 64 tons. "To achieve a cleaner use of coal, dust collector as a coal combustion dust control equipment, its role is very important." Shu Yinggang believes that in the flue gas treatment system, denitrification, dust removal, desulfurization system should perform their duties fully Play their roles and try not to negatively affect other systems. For example, NH3 overspray in the SCR denitrification device is liable to produce excessive ammonium bisulfate, so that the performance of the air precipitator and the precipitator is reduced. Excess fume entering the absorption tower will reduce the stability of the desulfurization equipment, and block the GGH and the demister; The cancellation of the GGH unit and the excessive flow rate of the flue gas in the absorption tower caused the chimney to produce a “gypsum rain” phenomenon.

To achieve cleaner coal use, source control is equally important. Huang Wei suggested that coal should be started from the source and scientific and rational use of coal should be done. For example, high-quality coal must be first used for civil use because the environmental protection facilities for small boilers are not complete, and the coal used in power plants must be as stable as possible, and coal cannot be burned. What coal. At the same time, we must improve the combustion technology, reduce the generation of pollutants and do a good job in terminal management.

One problem that should not be overlooked is that some of the built environmental protection facilities have reduced the effect of emission reduction because of the low level of operation and management. In this regard, Meng Hao told reporters that the effect of electrostatic precipitator dust and coal, boiler working conditions are closely related, the need for staff to adjust at any time according to the situation. However, many power plant personnel do not know enough about this, and it is easy to have problems if they do not change.

To do a good after-sales service and at the same time try to find ways to improve the level of management and maintenance of operational personnel has become one of the important tasks of FIDA Environmental Protection, Longjing Environmental Protection and other enterprises. “The annual operation and management training course held by Longjing has achieved certain results, but most of the staff attending the training are management personnel. The actual number of front-line operators is less. The direction of future training should be changed and on-site training should be done.” Meng Hao said that after the introduction of a subsidy policy of 0.2 cents/kWh, the feasibility of the dust removal BOT model can also be studied.