PM2.5 dissipates thermal power environmental protection cold reflection

Since January 12, 2013, many places in the country have seen PM2.5 “destroyed” and it has only been dissipated until today’s hazy weather. Scientific research shows that the main sources of PM2.5 pollutants are emissions from burning during daily power generation, industrial production, and vehicle exhaust emissions. Although the air quality has improved, but the PM2.5 "Burst Watch" incident has brought about the thinking of thermal power plants in the environmental protection field has just kicked off. Therefore, the reporter interviewed Zhang Rongchu, general manager of Nanjing Changrong Noise Control Environmental Protection Engineering Co., Ltd.

Reporter: Since January 12th, 2013, many PM2.5 “bursts” have been reported across the country. The pollutant emissions from thermal power plants cannot be relied upon. Please stand in the perspective of environmental protection in thermal power plants and talk about this PM2. 5 Views of the "Burst Watch" incident.

Zhang Rongchu: Since January 12, 2013, PM2.5 “bursts” have been observed in many parts of the country, mainly in northern China and eastern China. The haze has continued for many days, especially in the surrounding areas of the city where the concentration is higher and the people’s lives are better. Health has a serious impact. After PM2.5 fine particles are inhaled into the human body, they directly enter the bronchus, interfere with the gas exchange in the lungs, and cause diseases including asthma, bronchitis, and cardiovascular diseases. The physiological structure of the human body determines that PM2.5 does not have any filtering or blocking capabilities. However, the harm of PM2.5 to human health has gradually exposed its horrific side with the advancement of medical technology.

In recent years, the national phase promulgated the "Emission Standards for Air Pollutants from Thermal Power Plants" (GB 13223-2011) and the "Environmental Air Quality Standards" (GB3095-2012). Both standards have adopted PM2.5 as an important part of the assessment. PM2.5 refers to particles in the atmosphere that are less than or equal to 2.5 microns in diameter, and are also referred to as lung-infiltrating particles. Its diameter is less than 1/20 of the thickness of human hair.

It is well-known that PM2.5 is mainly derived from the daily industrial power generation, production enterprises, and automobile exhaust emissions. Raising the speed of city travel includes the construction of an urban public transport information system and a rapid transit system to reduce the exhaust emissions of automobiles. Since China’s urban population has exceeded the rural population, cities are places of concentrated life and production for people. Power generation and production companies are also built around the city, and the pollution they bring can be imagined.

The main reason for the PM2.5 numerical "burst" is that coal-fired combustion results in large quantities of sulfur dioxide, nitrogen oxides and dust. As one of the sources of PM2.5 pollution, the exhaust emissions of coal-fired boilers are very prominent. These enterprises are not only enterprises that serve the people, but also enterprises that pollute big people and bring health hazards to the people. In fact, the country can strictly implement the national standards for industrial power generation and production companies in accordance with the policy of stimulating domestic demand. In the end, there may only be two ways to go. One is to carry out environmental protection in accordance with the standards of the region; the other is to move to areas far away from the city and implement low-standard environmental standards.

Reporter: At present, what kind of status is the field of desulphurization in thermal power plants?

Zhang Rongchu: With the continuous progress and development of mankind, no new requirements are put forward on the quality of life, and new demands for power demand are constantly put forward. Due to the constraints of various technologies, China’s thermal power still accounts for more than 70% of the use. , And the power generated by thermal power to people at the same time a variety of sulfur dioxide, nitrogen oxides and other pollutants will also be discharged into the atmosphere.

How to maintain the normal operation of the desulfurization system of thermal power plants to a C repair time period is still a worldwide problem. At present, wet desulfurization is recognized as an efficient process in the industry. The wet desulfurization is the combination of flue gas and water in the flue of the power plant boiler, and quick lime in the desulfurization tower unit to generate wet smoke and calcium sulfate. Substances, through the heat exchange of air rotary flue gas-flue gas reheater (abbreviated as GGH), can increase the temperature of the flue gas desulphurization of wet flue gas desulfurization from 50 °C to 80 °C, thereby increasing the emission of smoke from the chimney The height of the lift, and if there is no GGH heat exchange can only be discharged within a dozen kilometers around the power plant.

From an environmental quality point of view, the main concern is the contribution of major pollutants (SO2, dust, and NOx) to ground concentrations when GGH is installed and not installed. As shown in the following table, in the same case, installing and canceling GGH has a great influence on air quality, especially dust and NOx concentration.

Installation and Cancellation of GGH Impact on Air Quality However, many desulfurization processes have so far failed to find a way to solve the problem of GGH blocking due to the production of calcium sulphate. Therefore, many domestic power plants have dismantled GGH for heat exchange and directly discharged to the atmosphere through the chimney. In the middle of the country, almost all GGHs in China's current six-generation power generation group, Datang Group, have been completely dismantled. The rest also have a large number of power plants that are being demolished and ready for demolition for safety production and economic benefits. At the same time, with the increasingly stringent environmental protection regulations and the increasingly prominent problems of PM2.5 in recent years, some power plants (especially those in the periphery of cities) are forced to start reusing the GGHs that have been dismantled.

Reporter: From the environmental protection point of view of the thermal power plant, what are the good appeals and suggestions for the government and the enterprises regarding the PM2.5 "Burst Watch" incident?

Zhang Rongchu: For the current PM2.5 (Bursting Table) situation, relevant national functional departments and agencies need to strictly enforce the law, seek to solve the current source of pollution control measures, and carry out a new technology for the whole society to seek the collection and treatment measures against the source of pollution. method.

At present, in the thermal power industry, the domestic traditional method of dust removal is the use of cyclones, electrostatic precipitators, etc., and in particular, electrostatic precipitators. The number of electrostatic precipitators accounts for 75% of the total domestic market. Due to the large range of dust particles produced in industrial processes, ranging from submicron molecular clusters to millimeter-sized particles that easily settle, the vast majority of existing new and old electrostatic precipitators are difficult to meet new emission standards. Electrostatic precipitators have high dust removal efficiency under normal operating conditions. However, for ultra-fine particles, up to 15% of the particles will leave the dust collector and be released into the atmosphere. Now many power plant desulfurization systems have eliminated the GGH (flue gas heat exchanger), resulting in the flue gas being discharged directly from the chimney into the atmosphere after passing through the dust collector. It can be imagined that this will cause much harm to the PM2.5 pollution in the atmosphere. The environmental protection department is expected to introduce mandatory regulations as soon as possible.

The main reason for the cancellation of GGH at many power plants is that they cannot solve the problem of headaches. It is recommended that the state solicit and solve the current ash removal and plug removal technologies in the process of desulfurization and introduce relevant promotion and support policies.

Related technology companies should also proactively promote themselves and serve well-sourced companies.