Pollutant emissions from modern incinerators (original) (raw)

Treatments of polluted emissions from incinerator gases: a succinct review

Reviews in Environmental Science and Bio/Technology, 2012

Due to the incomplete mineralisation of some organic compounds during the incineration of municipal solid waste, gaseous emissions are loaded with a large amount of particulate matter, undesirable elements and toxic molecules. Typically, an incinerator of urban solid waste produces large flows of hot gaseous emissions to be purified before being released into the atmosphere. In this paper, treatments of flue gas from a typical municipal waste incinerator are described. The first step is an energy recovery system through heat exchangers to make steam or hot water. Steam is used to produce electricity via a turbine. The economic balance of the total system is very often dependent on the heat recovery. The second step involves particle removal technologies. Different systems are available such as cyclones, scrubbers, electrostatic precipitators or baghouse filters. The third step is the removal of numerous molecule families such as acid compounds (SO x , HCl, HF), nitrogen oxides (NO x), metal species and many organic compounds. The latter include dioxins, furans and volatile organic compounds. Some treatment processes are described according to the pollutant family.

Flue Gas Composition and Treatment Potential of a Waste Incineration Plant

Applied Sciences

Waste-to-energy (WtE) incineration is an important technique in waste management systems and waste hierarchy. It is used to treat approximately 63% of the waste in European countries. The flue gas volumetric rate and its composition are essential to determine and monitor the emissions from waste incineration plants. This paper presents two methodologies used to evaluate the emissions from incinerators during the design phase. The first consists of a set of equations applicable in Excel (calculation model), while the second is the built-in components in Ebsilon 13.2 software which simulates the emissions from a furnace. This paper also proposes a comprehensive flue gas cleaning system for a simulated waste incineration plant in Jordan. According to Ebsilon, the results showed that for a 25 kg/s loading rate, there was 258,514 mg/Nm3, 749.90 mg/Nm3, 890.20 mg/Nm3, and 717 mg/Nm3 of CO2, NO2, SO2, and HCL, respectively. It was noted that these values relate to 1.5 of excess air ratio, ...

The benefits of flue gas recirculation in waste incineration

Waste Management, 2007

Flue gas recirculation in the incinerator combustion chamber is an operative technique that offers substantial benefits in managing waste incineration. The advantages that can be obtained are both economic and environmental and are determined by the low flow rate of fumes actually emitted if compared to the flue gas released when recirculation is not conducted. Simulations of two incineration processes, with and without flue gas recirculation, have been carried out by using a commercial flowsheeting simulator. The results of the simulations demonstrate that, from an economic point of view, the proposed technique permits a greater level of energy recovery (up to +3%) and, at the same time, lower investment costs as far as the equipment and machinery constituting the air pollution control section of the plant are concerned. At equal treatment system efficiencies, the environmental benefits stem from the decrease in the emission of atmospheric pollutants. Throughout the paper reference is made to the EC legislation in the field of environmental protection, thus ensuring the general validity in the EU of the foundations laid and conclusions drawn henceforth. A numerical example concerning mercury emission quantifies the reported considerations and illustrates that flue gas recirculation reduces emission of this pollutant by 50%.

Activated carbon treatment of municipal solid waste incineration flue gas

Waste Management & Research, 2013

Activated carbon injection is widely used to control dioxins and mercury emissions. Surprisingly little attention has been paid to its modelling. This paper proposes an expansion of the classical Everaerts-Baeyens model, introducing the expression of fraction of free adsorption sites, f s , and asserting the significant contribution of fly ash to dioxins removal. Moreover, the model monitors dioxins partitioning between vapour and particulate phase, as well as removal efficiency for each congener separately. The effects of the principal parameters affecting adsorption are analysed according to a semi-analytical, semi-empirical model. These parameters include temperature, contact time during entrained-flow, characteristics (grain-size, pore structure, specific surface area) and dosage of activated carbon, lignite cokes or mineral adsorbent, fly ash characteristics and concentration, and type of incinerator plant.

Dioxin and fly ash free incineration by ash pelletization and reburning

Environmental science & technology, 2001

Dioxins (DXNs) in municipal waste incinerator fly ash were effectively reduced by pelletizing the mixture of ash, cement, and sodium phosphate and reburning the pellets in a laboratory scale bubbling fluidized bed (BFB) furnace. Three types of pelletssA, B and C, of various sizes and compositions were used in the experiments. The efficiency of DXN reduction in the pellet matrix was proportional to the incineration time, temperature, and degree of pellet incineration. At 700°C and incineration time sufficient for a complete burnout, the efficiency of DXN reduction in the pellets of type A and C was found to be 99.9% and 99.7%, respectively. Correspondingly, the DXN concentration in the pellets decreased from 862 ng TEQ/kg to 0.9 ng TEQ/ kg for pellets A and 2.2 ng TEQ/kg for pellets C. The residual concentration of coplanar polychlorinated biphenyls (coplanar PCBs) was below 0.2 ng TEQ/kg and 0.4 ng TEQ/ kg, respectively. Assuming a tortuosity factor of τ ) 3 and the reaction rate constants of 0.013 m/s (at 700°C) and 0.025 m/s (at 800°C), the experimental pellet incineration times were reasonably predicted by using the shrinking core model. Possible DXN evaporation from the pellets was also studied. The amount of DXNs in the flue gas captured by an impinger trap was less than 3% when the reactor was operated at 700 and 800°C. The described method of fly ash pelletization and reburning seems to be a relatively easy and inexpensive way to reduce both the emission of DXNs and the amount of fly ash.

Municipal Waste Incineration 090830_GB

Throughout the past hundred years incineration plants for municipal waste have continuously been developed technologically. From the old days' incineration plants with a remarkable impact on the environment, today's state-of-the-art plants are pro-environmental and energygenerating units. Even small-sized plants are generating and supplying eco-friendly thermic energy to their respective communities. Several incineration plants furthermore generate electricity.