Coal power enters a new era of emission reduction

Coal burning can also be as clean as burning natural gas.

With the end of the boiler flushing of No. 1 generating unit of the Zhanneng Liuheng Power Plant, the first ultra-low emission desulphurization unit of the coal-fired power plant in China entered the whole start-up phase. It is the first low-emission, million kilowatts of domestic “three simultaneous” construction at the end of June. The unit was put into operation on time to lay a solid foundation.

Reduce the burden on the atmosphere

Dust, sulfur dioxide, nitrogen oxides and other harmful substances generated by coal combustion have always been an important source of atmospheric pollution. Among them, dust and nitrogen oxides are one of the main sources of smog formation. Sulfur dioxide is the source of acid rain.

In view of this, in recent years, China has increased the requirements for dust removal, desulfurization, and denitrification (removal of nitrogen oxides) of coal-fired power plants. Electrostatic precipitator has always been a standard for power plants, and desulphurization and denitrification devices have also been required to be completed in recent years. As the main force of Zhejiang's power generation industry, Zhe Neng Group, all of its coal-fired generating units have taken the lead in completing desulphurization reforms. Denitrification devices are also expected to be popularized this year and are at the forefront of major power generation groups in the country.

Increase environmental protection devices

Although domestic desulphurization, dust removal, and denitrification devices can generally achieve 90% or more of the results, relatively large amounts of coal (in Zhejiang, the annual consumption exceeds 100 million tons) still emit a staggering amount of emissions. According to data released by the Coal Industry Association, the total coal consumption in 2013 was about 3.7 billion tons, of which the coal consumption in the power industry was about 1.9 billion tons.

Therefore, the state has increased the control over the total emissions from the region, and has severely restricted the construction of new coal-fired generating units in the southeast coastal areas.

Under this background, the clean burning and clean discharge technology of coal has become a new space for the development of coal-fired power plants in the future, and the new blue ocean. Whoever can break through this technology will inevitably bring new development to the coal-fired power generation industry. opportunity. Zhejiang Energy, on the basis of basically fulfilling the national requirements for desulphurization and denitrification, once again led the Advanced Army coal ultra-low emission power generation field, and took the lead in presenting and implementing the “ultra-low emission of coal-fired unit flue gas” in the country, in accordance with the level of natural gas generating unit emissions. The new standard for ultra-low emission of coal-fired units has been formulated and it has been implemented in Jiaxing and Liuheng power plants. The application of this technology will make the emission levels of coal-fired power plants comparable to those of natural gas generators, and has been highly concerned by the relevant national ministries and commissions.

According to the national standards issued by the Ministry of Environmental Protection and the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China in July 2011, the specific emission limits of atmospheric pollutants are in the “coal boiler” column, with sulfur dioxide being 50 mg/cubic. Meters, nitrogen oxides are 100 mg/m3, and soot is 20 mg/m3; in the column of “gas-fired boilers or gas turbines”, sulfur dioxide is 35 mg/m3, and nitrogen oxide gas boilers are 100 mg/m3 gas turbine unit is 50 mg/m3 and soot is 5 mg/m3.

After the implementation of the ultra-low emission project, the flue gas emission standard for coal-fired power plants meets the natural gas unit standard. This project will also significantly reduce the emission levels of PM2.5, sulfur trioxide and mercury in the flue gas under the existing key regional emission standards.

In order to meet this standard, Zengeng added the latest and most advanced environmental protection technologies and devices in the industry, such as high-efficiency desulfurization and denitrification devices, and wet electrostatic dust removal, on the basis of existing environmental protection devices such as desulphurization, denitrification, and electrostatic dust removal from coal-fired power plants. Simply put, it is to do addition to increase the overall reduction effect of environmental protection devices and achieve ultra-low emission requirements. Of course, doing so will increase the power consumption of the power plant itself, but these efforts are worthwhile compared to the social benefits of clean emissions and the new space for power plant development.

Production started at the end of June

Through a continuous pipe-drainage test for a period of 7 days, a number of indicators such as the flue gas temperature and PH value in the absorption tower of No. 1 unit of Liuheng Power Plant met the design requirements. Sulfur dioxide, nitrogen oxides, and soot emissions are the three key indicators of ultra-low emission projects. The desulfurization absorber tower (see figure) is the core device that determines the desulfurization efficiency, and it is also the key to determine whether the wet electrostatic precipitator can achieve effective dust removal. Link.

The ultra-low emission project of Zhejiang Hengneng Liuheng Power Plant started construction on December 30th, 2012. It is different from the transformation of the old low-emission project of Jiaxing Power Plant under simultaneous construction. The ultra-low emission project of Liuheng Power Plant is the first and main project in the country. Simultaneous design, simultaneous construction, and simultaneous operation of the “three simultaneous” million-unit ultra-low-emission new construction project were undertaken by Zhejiang Tiandi Environmental Protection Company. After the project is implemented, the power plant will remove more than 70% of PM2.5. The emission concentrations of sulfur dioxide, nitrogen oxides, and dust from the flue gas will meet the emission standards of natural gas turbine units and become a high-standard clean power plant. According to the annual power generation of 5,500 hours, a single unit can reduce more than 270 tons of sulfur dioxide each year, reduce more than 820 tons of nitrogen oxides, and reduce 540 tons of dust.

If the existing 862 million kilowatts of coal-fired generating units in the country are all implemented with ultra-low emissions, the annual power generation will be calculated at 5,500 hours, and the use of coal in the six horizontal power plants will be the benchmark. Compared with the current national standards, the amount of sulfur dioxide can be reduced by 232,200 tons, and nitrogen oxides can be reduced. 706,800 tons of material and 465,500 tons of dust. Taking into account that Zhejiang Province is using the national key area emission limits, the actual data is likely to be higher than this value.

It is reported that the Ultra Low Emission Unit No. 1 unit of the Zhanneng Liuheng Power Plant is expected to enter the 168-hour test run in parallel with the main project in late June this year.