Waste includes domestic waste, hazardous waste and medical waste. my country produces more than 1 million tons of domestic waste per day, and it is growing at a rate of 7%-8% per year. Domestic waste incineration is the most effective way to achieve waste reduction, harmlessness, and resource utilization. Hazardous waste includes medical waste. Although the total amount is small, there are many types and more harmful. The flue gas composition of the incinerator is complex, the parameters are changeable, and the pollutants are various. After more than 20 years of research, the dry and semi-dry multi-component treatment process with bag filter as the main body has become the most practical treatment process for waste incineration flue gas.
Composition characteristics of domestic waste incineration flue gas:
• (1) Smoke and dust are very harmful and require strict pollution control: four categories, particulate matter (dust), acid gas (HCl, HF, SOX, NOX), heavy metals (Hg, Pb, Cr), organic highly toxic pollutants (II oxins, furans);
• (2) The flue gas has high moisture content and high dew point temperature: due to the existence of moisture and acid gas, the dew point is about 140°C, which is easy to condense;
• (3) Flue gas high and low temperature alternately exist: the flue gas temperature fluctuates greatly, normally around 200°C, the highest can reach 300°C, and the lowest is below 140°C;
• (4) The dust has strong hygroscopicity: it will cause the dust to be sticky, difficult to clean, and easy to block;
• (5) The dust particles are fine and the density is small: there are many fine dusts, and the dust less than 30μm accounts for 50-60%, the dust density is small, and it is difficult to clean the dust;
• (6) Strong corrosion: higher requirements are put forward for the corrosion protection of equipment and filter materials.
Requirements for filter media in waste incineration
• (1) Temperature resistance: long-term exposure to high temperature will not reduce its strength and cause damage to the bag.
• (2) Corrosion resistance: Oxidation resistance, acid resistance, hydrolysis resistance, high temperature non-hygroscopicity, resistance to water vapor and acidic substances in flue gas - chemical stability is the basis for guaranteeing the strength of the filter material.
• (3) Folding resistance: Long-term expansion and contraction movement must have sufficient mechanical strength as a guarantee, and the dimensional stability must be good to ensure that the filter bag remains unchanged for long-term use.
• (4) Ease of ash cleaning: Due to the complex composition of garbage, the toxic and harmful components in the smoke generated after combustion are also complex, and the generated smoke has a fine particle size and high viscosity.
• (5) Low-resistance and high-efficiency: Good air permeability, while the filtration accuracy must meet the requirements of emission standards, and the running resistance increases slowly, which is the basis for ensuring the service life of the filter material.
Selection of waste incineration filter media
• 1) The filter materials currently used in waste incineration conditions include PPS+PTFE composite needle-punched felt, PTFE needle felt, etc.;
• 2) Our company recommends MA301 glass fiber membrane laminated filter material and PTFE needle felt membrane laminated filter material.
