21th Century Business Herald: How can Thermal Power Plant Reduce PM 2.5 Emission

 

Although PM 2.5-targted fire coal emission standard has not been issued, sooner or later, the thermal power plants will have to adapt to the new environmental protection policies. After rounds of environmental protection policies requiring dust removal, desulfurization and denitrification, facing PM 2.5, the thermal power plants have made preparation in advance, instead of sitting still waiting for the influence on profitability imposed by new standards.

Judging from existing researches, to curb PM 2.5 emissions is not easy. So, in the end, can thermal power plants reduce PM 2.5 emissions? SEP has started the exploration in this area as early as 2012. SEP, a listed company controlled by CPI took the lead in PM 2.5 treatment.

Given China's existing environmental standards, even the exhaust gas purification facilities in thermal power plant reach to the state standards, they still cannot filter out smaller PM 2.5 effectively. Therefore, one solution is how to transform these tiny PM2.5 particles into larger ones, which are easy to capture.

At present, Shanghai Electric Power Co., Ltd Wujing Thermal Power Plant has 4 coal-fired units of 300,000 kilowatts, making it an important electricity and heat supply base in south of Shanghai. Last year, SEP invested nearly RMB 5 million Yuan to install a particulate aggregator on one coal-fired unit. Briefly, this particulate aggregator can change the fine particles in waste gas into positively charged particles, or negatively charged particles, and then combine these fine particles into larger one. On this basis, the electrostatic precipitator device in the thermal power plants can play its due role better.

Monitoring report made by State Power Environmental Protection Research Institute shows that this system can effectively reduce the PM 2.5 emission concentration to 10.6mg/m3 from 15.6mg/m3, a decrease of 30%. At the same time, the toxic elements such as mercury and arsenic emissions are also reduced. Furthermore, thank to its small size and lower cost, the technology used in this system has a bright prospect for spread.

In addition to the commercial demonstration of ‘particle aggregator’, SEP also invested huger amount of capital in technological transformation in Changxing Island No.2 Power Plant.

Changxing Island No.2 Power Plant is the smallest power plant invested by CPI. It only has two coal-fired units of 12,000 kilowatts and is the only heat supply base in Changxing Island. It is because of its small capacity that it is selected as the pilot of comprehensive gas management technique transformation, involving nearly RMB 30 million Yuan transformation costs.

In all processes of integrated governance, wet electrostatic precipitator facility has more direct effect in reducing PM 2.5 emissions. It absorbs fine particles through charged mist and electric force, while controlling a variety of emissions of other pollutants. This device needs an investment of RMB 5 million Yuan, while the imported technique to use in coal-fired units of millions of kilowatts will need nearly RMB 60 million Yuan.

The operation of the comprehensive treatment equipments allows the two units to reduce the PM 2.5 emission concentration by 34.8% and 55.6%. According to Shanghai Environmental Monitoring Center, the concentration of dust emitted by Changxing Island No. 2 Power Plant is 7.2mg/m3, well below the 20mg/m3, a standard designed by the state in next year.

Although Changxing Island No.2 Power Plant can get desulfurization subsidy of 0.015 Yuan / KWh, the cost of the whole system operation is f 0.04 Yuan / KWh, which bring pressure to Changxing Island No.2 Power Plant. However, as the desulfurization and denitrification develops, the following costs will be greatly reduced if the relating technology continues to improve.

For the electricity generating unit with millions of kilowatt, the SEP ‘multi-pollutant integrated collaborative governance technology’ also can play a role. In 2012, Shangdian-Caojing Power Generation Co., Ltd made low economizer transformation on two units of 100 kilowatts. Judging from the existing from the Real-time emissions data, we conclude that the emission standard of this company reaches to that of the gas power plant and the dust emission concentration maintains at about 14mg/m3.

Due to the complexity of the causes of PM2.5, this pollutant is difficult to detect. There is no final conclusion how much social responsibility the coal-fired power plant should shoulder. However, the practical actions taken by thermal power enterprises tell us that they are getting down to ‘declare war’ to PM 2.5. (Reporter Duan Xinxin)

 (This article is from 21th Century Business Herald November 29)

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