Bag House Research Articles

Design and Analysis of Fugitive Dust Emission Collector

This creative project explores the design and analysis of a novel fugitive dust emission collector, with a focus on its application in stone crusher units and crematorium facilities. Recognizing the detrimental health and environmental impacts of dust emissions, this project proposes a multifaceted approach. The core solution involves a combined system, this captures and removes larger dust particles through established methods like cyclones or bag houses. Dry fog dust suppression system, this technology utilizes atomized water droplets to suppress smaller fugitive dust particles, preventing their airborne spread. This project delves into the specific needs of stone crusher units and crematorium facilities. Utilizing CAD software, 3D models of the emission collector will be created, incorporating considerations like material selection, efficiency and airflow optimization, integration with existing infrastructure. Computational fluid dynamics (CFD) analysis by Simulating airflow patterns and dust capture efficiency within the collector. Assessing the collector's ability to withstand operational loads and environmental factors. This project aims to achieve, reduced fugitive dust emissions, enhanced environmental compliance, improved operational efficiency. Overall, this creative project showcases an innovative approach to fugitive dust control, potentially leading to improved environmental and public health outcomes in diverse industrial settings

A Study on Failure Rate, Reliability, and Collection Efficiency Trend of Bag Filters in a Cement Plant

This thesis presents a comprehensive study on the failure rate, reliability, and collection efficiency trends of bag filters in a cement plant over 15 years. Bag filters are vital pollution control equipment used in various industries, including cement plants, to maintain environmental compliance. Understanding their performance and failure patterns is crucial to ensure efficient and reliable operation while adhering to stringent pollution control standards. The research findings reveal that the failure rate trend of bag filters closely follows the bathtub curve, with an initial high failure rate, a period of lower failures, and a subsequent increase in failures as the equipment nears the end of its life cycle. Reliability trends align with Madhab's Hat curve, exhibiting higher reliability during the first 10 to 12 years of operation, followed by a decline in reliability. The collection efficiency of bag filters declines as the equipment ages, with the efficiency decreasing from 99.998% in the early years to 95.05% in the 15th year. This emphasizes the importance of maintenance and retrofitting for older dust collection equipment to maintain high collection efficiency. The study concludes that the typical life span of bag filters ranges from 10 to 15 years, after which major maintenance interventions are necessary to minimize failure rates. The research provides valuable insights for maintenance engineers, design engineers, and reliability engineers, enabling them to improve the performance of pollution control equipment, such as bag filters, reverse air bag houses (RABH), and electrostatic precipitators (ESP), to meet the pollution control standards set by regulatory authorities.

Comparison of sorbents based on Ca(OH)2 for removing HCl from flue gas

Due to EU climate change policy are coal-fired heating and power plant switching their fuel to biomass one. Emissions of flue gas from biomass are more environmentally friendly in general, but emissions of HCl and HF are increasing, and BAT limits are quite low for them. The possible solution is installation of technology DSI (Dry sorbent injection), especially with connection with bag house filter flue gas treatment. Powder of calcium hydroxide is one of suitable solution. Although the chemical composition is same, there are a huge differences in consumption between another types of Ca(OH)2. This article describes two most selling types of Ca(OH)2 in the Czech republic from the lime works in Štramberk (vz.1) and Čertovy schody (vz.2). This article is divided into laboratory part, where characterized both examples, and experimental part – operational test in the heating plant technology. The results of laboratory part were same for both examples in their thermal characteristic (thermogravimetry and DTA) and real density. Elementary and matter composition were quite similar, only sample 1 was a little bit contaminated by CaCO3 from original material. There was big difference in BET specific area – 14.8 m2·g-1 by sample 1 example and 41.273 m2·g-1 by sample 2. Sample 1 had the most of pore volume in pores with diameter 20-80 nm, the second one on had a more developed pore structure through the whole particle, Operational tests in same constructed CFB boilers were realized during two months in the same conditions. Control system of the heating plant mange cleaning technologies by emission limits, input fuel mixture was for both boilers same. Most of focused parameters were same, only data from DSI system were for each sorbent different. Efficiency of removing HF were for both sorbents same around 99%, for HCl around 85%. Consumption sample 1 was 80.63 m3 and 37.74 m3 of sample 2. When comparing the laboratory and operational parts, higher consumption of sample 2 can be caused by more developed porous structure and a larger specific BET surface. This may be due to the purity of the original material (CaCO3), which was also higher in sample 2, as well as the production technology of the sorbents.

A Real-World Industrial Application of Particle Swarm Optimization: Baghouse Designing

Due to the high ability and flexibility of meta-heuristic algorithms (MAs), they can widely be used in many applications to solve different problems. Recently, real-world engineering applications of these optimization algorithms have attracted researchers’ attention. This paper applies particle swarm optimization (PSO) as an effective population-based MAs to design the baghouse (BH). BH filters are among the most commonly used devices in air pollution control systems in mining and food manufacturers and power plants. Designing the BH depends on several parameters such as its capacity or airflow (Nm3/h), air-to-cloth ratio ([Formula: see text]), cam velocity, and installation limitations. Generally, industrial designers select the number and length of bags and their arrangement based on the experimental observations to meet the parameters mentioned above. The minimum cost or total weight of equipment is utilized for proposing a competitive price for suppliers. In this paper, a PSO algorithm is used to minimize the total cost by finding the best possible design (the number, length, and arrangement of bags). In addition, a real example of installed BH in a pelletizing plant is given and compared with PSO results to investigate the efficiency of the proposed algorithm. The results suggest that PSO can find a better design with minimum total cost than an installed BH filter, and therefore, PSO is applicable to industrial designers.

Characteristics and health effects of particulate matter emitted from a waste sorting plant

Solid waste components can be recycled in waste paper and cardboard sorting plants (WPCSP) through a multistep process. This work collected 15 samples every six days from each of the 9 points selected to study the processes taking place in a WPCSP (135 particulate matter samples total). Examining the concentration and size fraction of particulate matter (i.e., PM1, PM2.5 and PM10) in WPCSP is an essential issue to notify policy makers about the health impacts on exposed workers. The major activities for increasing of the concentration of PM in various processing units in the WPCSP, especially in hand-picking routes I and II were related to manual dismantling, mechanical grinding, mechanical agitation, and separation and movement of waste. The results of this work showed that a negative correlation between temperature and particulate matter size followed the order PM10 > PM2.5 > PM1. Exposure to PM2.5 and PM10 in the WPCSP lead to possible risk (HI = 5.561 and LTCRs = 3.41 × 10−6 to 9.43 × 10−5 for PM2.5 and HI = 7.454 for PM10). The exposure duration and the previous concentrations had the most effect on the ILCRs and HQs for PM2.5 and PM10 in all sampling sites. Hence, because WPCSP are infected indoor environments (I/O ratio > 1), the use of control methods such as isolation of units, misting systems, blower systems equipped with bag houses, protective equipment, a mechanical ventilation system, and additional natural ventilation can reduce the amount of suspended PM, enhance worker safety, and increase the recycling rate.

Selenium ligands doped ZnS for highly efficient immobilization of elemental mercury from coal combustion flue gas

At the upstream of electrostatic precipitator (ESP) or bag house (BH), using sorbents with excellent adsorption capacity is a common method for capturing mercury (Hg) from coal-fired power plant flue gas. ZnS, an inexpensively and conveniently prepared metal sulfide, can even be collected from nature, and is a promising candidate for its sulfur resistance. In this work, selenium ligands (Se 2− and Se 0 ) were introduced into ZnS for enhancing Hg 0 capture capability. The experimental results showed that the Hg 0 removal efficiency can reach 100% in a wide temperature range from 40 ℃ to 300 ℃ when the Se ratio was 30 wt% (30SZ). Compared with pure ZnS and Se powder, Se/ZnS were all exhibited an excellent absorbent capability. A long term experiment was imposed on 30SZ, and the sample adsorption capacity remained unchanged. Moreover, O 2 and SO 2 had insignificant effects on Hg 0 adsorption, NO showed a slight competition for Hg 0 adsorption. It was found that Se ligands (Se 2− and Se 0 ) and surface active S (S 2- and S) sites immobilized Hg 0 over the Se/ZnS surface, and in turn the adsorbed Hg 0 was basically converted to HgSe and HgS, and the adsorption mechanism was also proposed. With these advantageous performances, 30SZ is expected to be an economically feasible and scientifically sound sorbent. This work also provides a promising way for Hg 0 capture from coal combustion flue gas. • Inactive synthesized ZnS were functionalized to be highly efficient mercury sorbents. • The removal efficiencies can reach 100% in a wide temperature range from 40 to 300 ℃. • Se/ZnS had higher binding energy of Hg-Se to improve the adsorption capability. • The captured mercury is mainly converted into HgSe by chemisorption. • The components in the SFG have no obvious poison effects to synthesized 30SZ.

Power Consumption Analysis of Pulse Jet Filtration System Assisted with Pre-charger using Polyester Conductive Media

Energy consumption is a vital aspect for any industry considering the cost-effective aspect. The current study embodies the power consumption during filtration of conductive filters at different dust pre-charging levels on laboratory-based pulse jet tubular set up assisted with pre-charger. Three types of polyester conductive non-woven filter materials, viz. PTFE-coated media, stainless steel fibre blended with PET media and stainless steel scrim media, have been characterized at three different charge levels, viz. 4 kV, 8 kV, 12 kV, and without charge. The outcome revealed that there has been a significant drop in power consumption with the rise in pre-charge level. Energy utilization results have further been compared with full-scale bag house condition by calculating the energy consumed for 50 bags. The results showed that among all the materials taken for investigation the performance of PTFE-coated media is the best and role of material is most significant towards the energy consumption by the filtration system. Overall energy consumption decreases with rise in pre-charging level. It is observed that percentage contribution of energy utilized for fan has been much higher for full-scale bag house as compared to tubular-based set-up. However, in case of energy consumed by the compressor, the difference in percentage contribution is relatively less and for energy utilized due to charge, not much variation in contribution can be noted.

Emission characteristics of dl-PCNs, PCDD/Fs, and dl-PCBs from secondary copper metallurgical plants: Control technology and policy

This study investigated the characteristics of dl-PCNs, PCDD/Fs and dl-PCBs emitted from two typical secondary copper metallurgical plants processing copper sludge equipped with different sets of air pollution control devices (APCDs). Results indicated that the emission factors of dl-PCNs and PCDD/Fs of plant A are 0.00775 and 1.09 μg TEQ/ton, respectively, which are remarkably lower than those of plant B (3.12, 181 and 25.5 μg TEQ/ton for dl-PCNs, PCDD/Fs and dl-PCBs, respectively). Dl-PCNs contributed 0.7–2.7% of total TEQ for flue gases and up to 2.6% of TEQ for ash samples. The TEQ concentration of dl-PCNs in fly ash individually exceeds the regulated level of 1 ng TEQ/g regulated by Taiwan EPA, indicating that emission and discharge of dl-PCNs should be regulated. The combination of semidry scrubber and activated carbon injection (ACI) + baghouse (BH) is effective for simultaneous removals of dl-PCNs and PCDD/Fs in plant A; while the combination of cyclone, secondary combustion chamber, ACI + BH and wet scrubber (WS) is not optimal for removing dl-PCNs, PCDD/Fs and dl-PCBs. Memory effect occurring within BH and WS is responsible for low removal efficiencies of these POPs in plant B. This study suggests appropriate APCDs for simultaneous removal of three POP groups and recommends the inclusion of dl-PCNs in emission standard.

Reduction of polychlorinated naphthalenes (PCNs) emission from municipal waste incinerators in Taiwan: Recommendation on control technology

Emission factor and removal efficacy of PCNs are evaluated via the flue gas sampling of two MWIs equipped with different air pollution control devices (APCDs) in Taiwan. MWI-A is equipped with ESP, wet scrubber (WS) and selective catalytic reduction (SCR), while cyclone (CY), semi-dry absorber (SDA), activated carbon injection (ACI) and baghouse (BH) are employed in MWI-B. The average concentrations of PCNs measured at stacks of MWI-A and MWI-B are 2.1 ng Nm−3 (0.218 pg TEQ Nm−3) and 23.2 ng Nm−3 (0.425 pg TEQ Nm−3), respectively. The emission factors of PCNs calculated from feeding rates of waste and stack sampling results range from 6.7 to 6.95 μg t−1 (0.790–1.45 ng TEQ t−1). PCNs are formed in ESP via chlorination, while SCR and SDA + ACI + BH are effective in removing PCNs with the overall efficacies of 97.6% and 94.3%, respectively. PCN removal efficiencies achieved with SCR and SDA + ACI + BH increase as chlorination level increases. Specifically, around 72% and 82% of Mono-CN are removed by SCR and SDA + ACI + BH, respectively. The removal efficacies of other homologues achieved with SCR are consistently high (96–100%). Dominances of Mono-to Tri-CNs in scrubbing liquid collected from WS and higher removal efficacies of these homologues achieved with WS + ESP compared with ESP alone indicate that WS can capture low chlorinated PCNs to some extent. The results suggest that CY + SDA + ACI + BH should be equipped in MWI for effective removal of PCNs, while ESP, WS and SCR should be utilized with precaution to eliminate PCNs formation and enhance the PCNs removal efficiency.

Appraisal of SOx Emission from Flue Gas in Thermal Power Station and Dry Sorbent Injection (DSI) Method to Reduce SOx

Electrical vitality created in any nation is one of the advancement estimates happens in that nation. The vitality delivered is principally founded on the accessible assets, for example, streaming water, coal, oil, gas, atomic fills, wind, sunlight based and so forth. The accessibility of wealth coal in India had incited the influence plant organizers to introduce coal based warm influence stations. During the pre-autonomy and post-freedom period in mid fifties, the need was to produce control and consequently much consideration was not paid to the contamination perspective and this proceeded up to late seventies. Most of intensity plants in India extending from not many MW to 500 MW or more are of pummeled fuel terminated boilers using low calorific, low coal sulfur, high debris content sub-bituminous coal. Because of consuming of the coal, discharges, for example, Particulate Matter (PM), Oxides of Sulfur (SOx) and Oxides of Nitrogen (NOx) aside from CO2, CO are diverted to the climate through the vent gas. The mindfulness made by contamination impact on the general public and the tremendous measure of disintegration exposed to the gear constrained the specialists to make contamination standards increasingly stringent. In this paper, the methodology to reduce SOx from flue gas in an old lower capacity power station is discussed and the optimum and cost effective methodology adopted is Dry Sorbent Injection (DSI) by injecting sodium bicarbonate or sodium carbonate or trona in the flue gas path after furnace and before/after Air-preheater to remove SO2/SO3 from the flue gas. The removed sulphate will be collected along with ash in ESP or Fabric Filter in a Bag house

Feasibility Analysis of Drying Sludge Using Flue Gas Waste Heat

Using sewage sludge as fuel has been considered an effective way to handle the sludge. However, due to the high water content, sludge is required to be dried before it can be burnt. In this paper, a paddle sewage sludge dryer was proposed to add after bag house gas filter (BHF) and before flue gas quench (FGQ), which can use the waste heat of the flue gas (FG) and therefore, improve the overall efficiency of the biomass-based plant and sludge handling. A mathematical model was developed to simulate the heat transfer in the paddle dryer, which was validated through the comparison with measured data. Based on this model, the impacts of flow rate of sludge and stirrer speed on the moisture content of exit sludge, temperature of exit sludge were studied. The results show that the increase of stirrer speed or the decrease of sludge mass flow rate all can reduce the moisture content of exit sludge.

Emission and Heavy Metal Content Characteristic of Densified Refused Derived Fuels of Oil Sludge and Biomass Combination as an Alternative Fuel for Cement Plant

Hazardous Waste such Oil Sludge combined with biomass (coconut shell and rice husk) was utilized as an alternative fuel in cement plant in form of Densified-Refused Derived Fuel (D-RDF). D-RDF were Co-Processed with primary fuel into Rotary Kiln in order to reduce usage of fossil fuel and eliminate the hazardous waste by thermal treatment, meanwhile to recover the energy contained in the D-RDF, the utilization of these waste are expected without causing adverse effect into the environment. Co-Processing of D-RDF as alternative fuels into cement plant kiln must follow the regulation applied in Indonesian Environment and Forestry Minister regulation 19/2017 and European Union for Responsible Incineration and Treatment of Special Waste (EURITS). Based on previous research, D-RDF composition of oil sludge and biomass at 1:1 ratio with 5% starch addition was choose as they give best calorific value at 6000 kcal/kg. The objective of these research are to observe the emission caused by the utilization of these D-RDF and potential effect into cement or clinker product. The result show NOx and CO value are meet the standard requirement by government regulation meanwhile SO2 value which are 1251 mg/Nm3 and 1500 mg/Nm3, over the regulation standard which is 650 mg/Nm3. This issue could be overcome in the plant with pre treatment of D-RDF and utilization of Bag House Filter or Electostatic Precipitator before release the emission to the stack. Trace element analysis of D-RDF ashes (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Se, Sn dan Zn) show the result are meet the EURITS regulation, which mean utilization of D-RDF will not give quality deffect to cement or clinker product.

A Study of Mechanical Properties of High Strength Concrete

High strength concrete is widely used for construction of high rise structures like bridges and dams so on. But using high strength concrete cost us more. Alternatively we can use some admixtures which can increase strength indirectly. In this project we have used GGBS, MICROSILICA AND ALCCOFINE and CRYSO is 1% in chemical admixture. On conducting different trail mixes we have come to know that by using 0%, 5%,10%,15%,20% and 25% is tested in normal water for 3, 7, 28 days. The results showed the suitability of concrete improvement in strength in normal water. In this paper reports from few researchers have been studied on strength and durability performance of alccofine as a partial replacement of cement in concrete. The efforts made by the researchers for enhancing the performance of concrete over the last few years proved that supplementary cementitious materials with mineral and chemical admixtures can improve the strength and durability of concrete. Alccofine is one among the supplementary cementious materials. Alccofine is new pozzolanic material which is bringing technical revolution in the construction industry. From the survey it is found the alccofine can achieve high strength when is replaced by cement at 0% - 20% compared to the traditional concrete. Micro silica is an amorphous type of silica dust mostly collected in bag house filters as by-product of the silicon and ferro-silicon production. The paper summarizes important physical and chemical properties of micro silica and uses those results for an evaluation of micro silica from a Health Safety and Environment (HSE) standpoint. Micro silica consists of spherical particles with an average particle size of 150 nm and a specific surface area of typically 20 m3/g. The chemical and physical properties of this inorganic product are different as compared to other amorphous and crystalline silica poly morphs. More than 500.000 MT of micro silica are sold to the building industry world-wide and are used in fibre cement, concrete, oil-well drilling, refractories, and even in polymers.

Effect of Particle Size on Collection Efficiency of ESP and RABH: A Case Study

Electro Static Precipitator (ESP) is a conventional dust collecting equipment used in various process industries. Nowadays bag houses and Reverse Air Bag Houses (RABH) are also widely used in place of ESP. RABH is comparatively new technology which is used in cement plants and also other industrial facilities for dust collection. The dust collection efficiency of the ESP and RABH depend on many factors and particle size is one of those factors. Many researchers have done research on the collection efficiency of ESP with respect to the particle size distribution in dust-laden inlet gas, however, there is merely any study done on RABH collection efficiency with respect to the dust particle size distribution. A case study has been conducted in this research to find out the relationship between particle size distribution and collection efficiency of RABH in a cement plant. In addition to this, the collection efficiency of ESP is also studied with respect to the dust particle size distribution in inlet gas. The study has been conducted by taking the samples at inlet and outlet of ESP and RABH for calculation of efficiency and different particle size percentage at inlet side. It is found that the collection efficiency of both ESP and RABH is dependent on the size of the incoming dust load. In ESP the collection efficiency is higher when the particle size is smaller than 0.2 μm (PM0.2) and larger than 1 μm i.e., PM2.5 and PM10. The collection efficiency is lower when the particle size lies between 0.2 and 1 μm. In RABH it is observed that the collection efficiency increases with increase in the size of dust particles. Also a comparative study has been conducted to find out the better system between ESP and RABH by the help of sampling analysis (t test), field survey and performance parameter study. It is found that RABH is better than ESP in terms of collection efficiency and other performance parameters.

Heat recovery from spray dryer exhaust air: An example from an infant formula factory installation

This article describes a successful installation of a heat recovery system at the exhaust air stream on a commercial spray dryer for infant formulae. The entrained product particles prohibit a straightforward heat exchanger setup. Therefore, special provisions have to be made to avoid fouling: a bag house filter prior to cooling of the exhaust air stream, and an exceptional heat exchanger design with a low on-flow gas velocity, thick fins, and wide gaps, which facilitate wet cleaning. The optimization of the heat integration of the recovered heat into the production line used the pinch point method as a structured approach. It recommended three temperature levels; namely for the supply of the tanks for the cleaning fluids (lye and acid) for the cleaning-in-place (CIP) procedure, the fluid bed inlet air heaters, and the main inlet air pre-heaters. After 1 year of operation, the control software has been adjusted to better consider the buffering characteristics of the CIP tanks, and to operate the preheaters with a seasonally floating setpoint to recover more heat in spring and in autumn.

DESIGN OF LCU FOR REVERSE AIR BAG HOUSE IN CEMENT INDUSTRY

The term LCU refers to the Local Control Unit. Cement industry may contribute significantly to the air pollution level in the vicinity of the industry. Large quantities of pulverized material are handled and the main air pollution is emission of dust. Dust is generated at all stages in cement manufacturing process from quarrying through crushing, homogenizing, burning, handling and storing to the final distribution. Reverse Air Bag House (RABH) is used to control industrial particulate pollutants. The term bag house refers to a filtration technology that uses cloth or synthetic filters for the dust collection. It consists of several bags inside it above the hopper. Dust particles from the raw mill, pre-heater are fed to this reverse air bag house section. The bag filter filters the dust outside of the bag. On cleaning the fine dust particles, it falls into the hopper and stores on the silo. Hence 99% of the fresh air is exhausted outside. The proposed system will automate the Reverse Air Bag House unit separately using PLC and SCADA.

Measurement of effective filtration area of pleated bag filter for pulse-jet cleaning

A pleated filter cartridge is a potential component to reduce the installation space required for a bag house dust collection system. However, the optimal pleating method has not been suggested yet, and it has been dependent upon the manufacturer's know-how and experience. In this study, dimensionless parameter, α, which is the ratio of pleat height to pleat width, was introduced to determine the optimal pleat geometry of a pleated filter cartridge. Eight different pleated filters were prepared to determine the effect of α and pleat length, PL, on the filter cleaning efficiency. A lab-scale pulse-jet bag house system which could install four filter bags and to be capable of on-line filter cleaning, was used to perform the filtration tests. Based on experimental data, a pleated cartridge filter with α = 2.21 had the maximum effective filtration area, and filter cleaning efficiency. However, we observed a drastic decrease in filter cleaning efficiency for a filter with an α value higher than 2.21. Therefore, we found that the tested cartridge filter had the optimal filter pleating geometry at α = 2.21, which folds a filter medium as a ratio of pleat height to pleat width, 2.21. In addition, the effective filtration area of a pleated filter cartridge was measured by the relationship between the increase in pressure drop during each filtration cycle, and multiplication of dust concentration and elapsed time. The ratio of the effective filtration area and theoretical filtration area, β, depends on the filtration cycle and the α value at the initial stage; however, it only depends on the α value at a later stage.

Non-uniform filtration velocity of process gas passing through a long bag filter.

Filtration velocity is one of the dominant parameters that determine the pressure drop through a bag filter. Experimental investigation of the air flow pattern around a bag filter inside a bag house is very difficult because of the complexity of the 3-D air flow. For this reason, we numerically investigated flow characteristics along a bag filter in detail. We newly found that the filtration velocity is non-uniform along the axial direction of a long bag filter when the height of the filter is greater than 10 m. The filtration velocity is very small at the bottom of the bag filter but very large at the top. For bag filter lengths of over 10 m, 70% of total inlet flow is filtered in just the top 30% of the long bag filter. This indicates that the top section of the long bag filter could deteriorate faster than the bottom section, making it necessary to develop a new method to avoid the problem. We developed an equation that can help predict the initial pressure drop across long bag filters with different heights, but identical filtration characteristics.

Emission Control Technologies for Thermal Power Plants

Coal thermal power plants are one of the primary sources of artificial air emissions, particularly in a country like India. Ministry of Environment and Forests has proposed draft regulation for emission standards in coal-fired power plants. This includes significant reduction in sulphur-dioxide, oxides of nitrogen, particulate matter and mercury emissions. The first step is to evaluate the technologies which represent the best selection for each power plant based on its configuration, fuel properties, performance requirements, and other site-specific factors. This paper will describe various technology options including: Flue Gas Desulfurization System, Spray Dryer Absorber (SDA), Circulating Dry Scrubber (CDS), Limestone-based Wet FGD, Low NOX burners, Selective Non Catalytic Reduction, Electrostatic Precipitator, Bag House Dust Collector, all of which have been evaluated and installed extensively to reduce SO2, NOx, PM and other emissions. Each control technology has its advantages and disadvantages. For each of the technologies considered, major features, potential operating and maintenance cost impacts, as well as key factors that contribute to the selection of one technology over another are discussed here.

Chemical speciation of lead in secondary fly ash using X-ray absorption spectroscopy

In this study, fly ash samples were collected from bag houses in a Chinese municipal solid waste incinerator (MSWI) and secondary fly ash (SFA) samples were collected from a high-temperature tubular electric furnace by thermal treatment of MSWI fly ash at 1050, 1100, 1150, 1200, and 1250 °C.We determined the speciation and atomic coordinates of lead in SFA using X-ray absorption spectroscopy (XAS) techniques. The results obtained by X-ray absorption near edge structure (XANES) spectra revealed that the mass fraction of PbO in MSWI fly ash was 57.9% (wt %) while PbCl2 and PbS were the dominant species in SFA. Extended X-ray absorption fine structure (EXAFS) data analysis indicated the atomic coordinates of Pb were proportional to the weights of PbCl2 and PbS, in good agreement with the XANES spectra. These findings highlight lead evaporation processes in the MSWI fly ash during heat treatment and provide a method for consistent speciation analysis of environmental samples using XAS.