Detailed Explanation of Basic Knowledge of Garbage Incineration Power Plant (Part 3)
May. 26, 2020
04 Requirements for discharge and treatment of pollutants from waste incineration power generation
1. Engineering Technical Requirements
The annual operating time of each incineration production line should be more than 8000 hours, and the design service period of theincineration system should not be less than 20 years.
The effective volume of the garbage pond shall be determined according to the rated garbage incineration volume for 5 to 7 days. Garbage ponds should be equipped with garbage leachate collection facilities. Domestic garbage storage facilities and leachate collection facilities should adopt closed negative pressure measures and ensure that they are under negative pressure during the operation period and furnace shutdown period. The gas in these facilities should be preferentially passed into incinerators for high-temperature treatment or collected and discharged after meeting the requirements of the "Standard Pollutant Discharge Standard" through deodorization treatment.
The waste to energy system should ensure that the garbage is fully burned in the incinerator. The flue gas in the secondary combustion chamber should be kept at a temperature of not less than 850 ℃ for not less than 2 seconds. The incinerator slag heat reduction The rate should be controlled within 5%.
The waste incineration line must be equipped with a flue gas purification system, and it should be arranged in a unit system. The choice of the flue gas purification process should fully consider the changes in the characteristics of garbage and the number of incineration pollutants produced, as well as the impact of their physical and chemical properties, and pay attention to the matching between the combined processes.
Removal of acidic pollutants: acidic pollutants include hydrogen chloride, hydrogen fluoride, sulfur oxides, nitrogen oxides, etc., and appropriate treatment processes should be used to remove them.
Measures should be taken to strictly control the emission of dioxins in the flue gas, including controlling the temperature, residence time and airflow disturbance conditions of the incineration flue gas in the combustion chamber; reducing the residence time of flue gas in the temperature range of 200 ℃ ~ 500 ℃; setting activated carbon Powder and other adsorbents are sprayed into the device.
2. Operational regulatory requirements
The amount of garbage stored in the garbage storage pond should be regularly monitored, and effective measures should be taken to discharge the leachate in the garbage storage pond. The leachate should be discharged after treatment.
On-line monitoring of the operating status of the incinerator should be achieved. The monitoring items should include at least the combustion temperature of the incinerator, the furnace pressure, the oxygen content of the flue gas outlet, and the carbon monoxide content. A sign should be set up in a prominent position to automatically display the main parameters and smoke of the operating conditions of the incinerator. Online monitoring data of major pollutants in the gas.
Automatic and continuous online monitoring of flue gas should be achieved. The monitoring items should include at least hydrogen chloride, carbon monoxide, soot, sulfur dioxide, nitrogen oxides, etc., and be connected to the local environmental sanitation and environmental protection authorities to achieve real-time data transmission.
Slag and fly ash generated by garbage incineration shall be properly handled or disposed of in accordance with regulations.
Effective odor control measures should be taken in each process, and the plant area should be free of obvious odors; deodorization systems should be used as required at relevant locations and maintained in a timely manner as required.
In garbage storage tanks, sewage and leachate collection tanks, underground buildings, production control rooms, and other places where biogas is easily collected, daily monitoring and supervision should be strengthened to ensure safe production.
3. Waste gas treatment requirements
The waste gas emitted by the waste incineration plant mainly comes from the flue gas generated by the incineration process. The main pollutants are dust, hydrogen chloride (HCl), sulfur dioxide (SO2), nitrogen oxides (NOX), carbon monoxide (CO), organic pollutants, Dioxins, and heavy metals.
The computer control system can achieve a high degree of automation of waste incineration, heat energy utilization, flue gas treatment, and other processes, control the set combustion conditions (such as furnace temperature is higher than 850 ℃, flue gas residence time is greater than 2 seconds, to maintain flue gas turbulent flow and Moderate peroxygen), so that the incineration system operates under rated conditions, the original emission concentration is reduced to a minimum, and to ensure the complete decomposition of organic substances such as dioxins.
Install a variety of effective flue gas treatment equipment, such as bag dust removal, activated carbon adsorption of harmful substances, etc., and use a flue gas online monitor-to continuously monitor the flue gas emission indicators of each incineration line to ensure the emission of flue gas pollutants from waste incineration plants Meet the required standards.
4. Odor control requirements
The compressed transport truck with good airtightness and automatic loading and unloading structure should be used to transport garbage to minimize odor overflow.
An air curtain should be installed at the entrance and exit of the garbage discharge hall, and the electric discharge door should be closed before and after the discharge of the garbage truck to prevent the odor from escaping.
The garbage pond should adopt a closed design, with an air suction port above the garbage pond to guide the malodorous gas as combustion air into the incinerator for high-temperature decomposition, and make the garbage pond and the discharge hall under negative pressure.
Spare activated carbon exhaust gas purification facilities should be set up. During the maintenance shutdown of the whole plant, the odor in the garbage pond must be purified by the activated carbon exhaust gas purification facilities before it can be discharged.
5. Dioxin emission control requirements
The so-called dioxin is actually an abbreviation for dioxin. It refers to the two major categories that contain many similar species or isomers with similar structure and properties. There are a total of 210 organic compounds, but only a few of them are Species are considered toxic.
Dioxin is not a unique public hazard in waste incineration plants. It is a compound produced by heating organic matter together with chlorine and is a relatively common chemical phenomenon. Dioxins can be found in the air, soil, water, food, and garbage. Studies have shown that food is its main source. About 90% of the dioxins in human contact come from the diet.
The waste incineration plant controls the emission of dioxin, mainly adopting the mature "3T" and high-efficiency purification technology. One is to maintain the temperature in the incinerator chamber above 850 degrees, and control the flue gas to stay in the furnace for more than 2 seconds so that It is completely decomposed; the second is that the flue gas passes through the most advanced purification treatment system to control the unit dioxin concentration within 0.1 (ng TEQ / m3), reaching the most stringent international emission standards.
6. Slag and fly ash control requirements
The slag is mainly the residue of household garbage after incineration, and its production depends on the composition of the garbage. Its main components are manganese oxide (MnO), silicon dioxide (SiO2), calcium oxide (CaO), and aluminum oxide (Al2O3), Iron oxide (Fe2O3), scrap metal, and a small amount of unburned organic matter.
After the slag generated by garbage incineration is treated at a high temperature and harmless, and then separated by magnetic separation, etc., the slag can be comprehensively used, and the part that cannot be comprehensively used can be sent to the sanitary landfill for landfill.
Each device of the fly ash collection, storage, and processing system should be kept in a closed state. When the flue gas purification system uses dry or semi-dry methods to remove acid gases, the fly ash treatment system should adopt mechanical or pneumatic ash removal methods; when using the wet method, the fly ash should be effectively separated from the sewage.
Fly ash is a hazardous waste and must be collected separately. It must not be mixed with domestic waste, incineration residues, etc., or mixed with other hazardous waste. Fly ash from incineration of garbage shall not be stored in the factory area for a long period of time, shall not be subjected to simple disposal, and shall not be transported out and discharged at will.