Figure 3
Effect of gas flow rate on pressure drop in the turbulent wet scrubber (color figure available online).
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A turbulent wet scrubber was designed and developed to scrub particulate matter (PM) at micrometer and submicrometer levels from the effluent gas stream of an industrial coal furnace. Experiments were conducted to estimate the particle removal efficiency of the turbulent scrubber with different gas flow rates and liquid heads above the...
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Context 1
... medium — passes through the zone in front of the gas and liquid separator, which collects liquids and particles and reduces the pressure loss at the following demister. After liquids and particles are collected in the separation zone, the remaining air stream passes through the demister to eliminate water mist and particles. Figure 2 represents a schematic sketch for a performance test of the TWS. The turbulent scrubber consists of a vertical inlet pipe at the center, through which the air and fly ash (as dust particles) enter the scrubber. The solid aerosol particle generator is connected to the inlet pipe to feed fly ash brought from a nearby thermal power plant at different concentrations. A portable aerosol spectrometer (portable dust monitor with 15 particle size channels, model 1.108, Grim, Germany) is connected to the inlet and outlet pipes of the scrubber to measure the particle concentrations and size distribution. A Testo 350 – S/XL (Germany) is used to measure the pressure loss across the scrubbing section of the turbulent scrubber. The three selected parameters that affect particle collection efficiency are the input concentration of particulate matter, the water level in the water reservoir of the TWS, and the flow rate of the air stream. The particulate scrubbing process in the turbulent wet scrubber was carried out for three different water levels filled through the opening of the nozzle from the water reservoir. The air stream at different flow rates (5.13 m /min and 7.62 m /min) and containing different input concentrations of particulate matter (230.84 mg/min, 110.89 mg/min, and 48.78 mg/min) was prepared with the aerosol feeder by adjusting feed rates to 10, 5, and 2, respectively. The air stream was then fed into the turbulent scrubber system. Fly ash was used to adjust concentrations of particulate matter in the air stream. The fly ash obtained from a coal power plant is a powder type with a spherical shape, and its major components are alumina (Al 2 O 3 ) and silica (SiO 2 ). The fly ash has an average diameter of 20 – 30 m m, an apparent density of 800 – 1000 kg/m 3 , and a true specific weight of 1.9 – 2.3. The dust-laden gas enters the scrubbing chamber by displacing the water in the vertical inlet pipe, and passes through a small rectangular nozzle of dimensions 760 mm  25 mm to a horizontal exit parallel to the liquid surface in the inner compart- ment of the scrubber. The water level of the scrubber is varied between 0 cm, 32 cm, 34 cm, and 36 cm from the bottom of the water reservoir. The lateral movement of the gas stream at the surface of the water for the first level (0 cm) scours the water surface and throws the particulate matter onto the deflectors, thereby creating agitation in the water column. At higher gas flow rates, the gas passing through the nozzle exits at high velocities, leading to vigorous agitation of the liquid and throw- ing of particular matter onto the curved deflector. The liquid climbs upward in the curved deflector and falls back to the bulk liquid, enclosing the gas in the form of bubbles. Thus, heavy turbulence is created by the gas stream in the stagnant water within the curved deflectors. For liquid levels of 32, 34, and 36 cm, the exit of gas from the nozzle leads to very high turbulence and results in a homogeneous gas and liquid mixture in the scrubber. This homogeneous gas and liquid mixture rises quickly and overflows above the deflectors to the rest of the chamber through the upper part of the deflector, as shown in Figure 2. Significant turbulence is created by gas bubbles formed in the rest of the chamber due to falling of the homogeneous medium. Thus, the entire scrubbing chamber is kept under turbulence and performs the particulate scrubbing process effectively. The downward-curved deflector prevents the entrainment of fine liquid droplets that arise due to bursting of the bubbles at the surface of the liquid. Turbulent wet scrubbers are high-energy scrubbers. High energy is utilized at the expense of gas- or liquid-phase energy to create turbulence in the scrubbing section for more efficient scrubbing. The turbulent scrubber used in the present study utilizes gas-phase energy in the form of high-velocity gas to displace the liquid in the inlet pipe and create turbulence in the scrubbing chamber. The pressure drop in the turbulent scrubber depends on the gas flow rates, the nozzle dimensions, and the liquid heads above the nozzle. The initial water level in the water reservoir was kept just below the nozzle (0 cm) and the pressure drop was measured for different gas flow rates. This pressure drop indicates the energy spent by the gas medium in scouring the liquid from the surface into films and droplets, and thereby creating turbulence for scrubbing. The pressure drop is due to the liquid head above the nozzle, and is measured at different gas flow rates for liquid levels of 32 cm, 34 cm, and 36 cm from the bottom of the reservoir. Figure 3 shows the effect of the gas flow rate on the pressure drop in the turbulent scrubber. As the gas flow rate increases, the pressure drop also increases. The pressure drop of fluid flowing across a system is directly proportional to the square of its velocity. Figure 3 also shows that there is a significant difference between the pressure drops across the turbulent scrubber with and without the liquid level above the nozzle. The pressure drop without the liquid is less than 20 mm H 2 O for the given gas flow rates, and it increases gradually along with the gas flow rate. The pressure drop across the nozzle is dominant compared to the liquid volume that is scoured upward in the deflector in the homogeneous form. Hence, the pressure drop is minimal compared to the pressure across the nozzle with the liquid head. The pressure drop for the system with a water head above the nozzle shows a different trend than the system with a pressure drop without a liquid head. The pressure drop increases steeply for gas flow rates up to 5 m 3 /min. Above 5 m 3 /min, the pressure drop increases gradually to reach a saturation level. The ratio of energy spent in creating turbulence is greater than at lower gas flow rates than at high flow rates, even though more liquid is kept under turbulence. Figure 4 shows the effect of the liquid level on the pressure drop. As the liquid head increases, the energy spent in homogenizing the liquid increases. Hence, there is a steep increase in the pressure drop with respect to the liquid level in the system. Figure 4 also reveals that the pressure drop increases along with the gas flow rate due to the hydrostatic head above the nozzle and frictional losses. In wet scrubbing, fine particles are scrubbed mainly under the influence of flux forces. In turbulent scrubbers, these flux forces aid in scrubbing the particulate matter. As the particle size (fly ash) increases from 0.65 μm, the efficiency of the turbulent scrubber increases and reaches almost 100% for particles around 5 μm (Figure 5). For a water level of 32 cm in the scrubber, the efficiency is around 43%. For water heads of 34 cm and 36 cm above the nozzle, the scrubbers reach efficiencies above 52% and 53%, respectively. There is a significant difference in particle scrubbing efficiency (ranging from 5% to 9%) for liquid heads between 32 cm and 34 cm in the scrubber for particles in the range between 0.65 μm and 1.0 μm, whereas for particles larger than 1.0 μm, the efficiency is almost the same for all liquid levels. The difference in percentage may be small, but it counts as the sizes of the particles are around the submicrometer level. Thus, liquid levels of 34 cm and 36 cm above the nozzle have a scrubbing efficiency more than 50% better for the smaller particles, even those ranging from 0.65 μm to 0.8 μm. Higher gas velocities lead to more turbulence in the scrubber, resulting in higher scrubbing efficiencies. Higher gas velocities also result in greater pressure drops in turbulent scrubbers. Figure 6 shows the particle removal efficiency of the turbulent scrubber at two different gas flow rates. For the higher gas flow rate, the efficiency of the turbulent scrubber is found to be predominant for submicrometer particles. Thus, there is a marked difference in the particle removal efficiency of the turbulent scrubber for particles smaller than 1 μm. The efficiency curves for the two gas flow rates merge with each other for larger particles, indicating that turbulence effects due to different gas flow rates do not affect the efficiency substantially in the case of particles larger than 2 μm. Thus, the contact between the gas and liquid for particle removal is established well for larger particles even at low gas flow rates, and the efficiency almost reaches 100%. A plot relating the pressure drop to the scrubbing efficiency gives insight into the energy spent in achieving the range of efficiencies for the given size distribution of particles. A correlation analysis for predicting particulate removal efficiency in the turbulent scrubber with respect to the energy spent was carried out by utilizing the contacting power theory approach. This approach predicts the size distribution of droplets or bubbles for different gas flow rates in the case of a turbulent scrubber in which the gas – liquid mixture is a homogeneous medium. Since the turbulent wet scrubber developed in this study falls between the droplet and bubble scrubber categories, the scrubbing efficiency can be directly associated with the energy spent in creating the turbulence in the system. Lapple and Kamack (1995) show that in wet scrubbing design, efficiency can be related to the energy expended in producing the actual gas – liquid contact. Thus, the contact power is the energy dissipated per unit volume of gas treated, which can be estimated from the total pressure drop in the turbulent scrubbing system. In the present turbulent scrubber, the energy spent in ...
Context 2
... through the demister to eliminate water mist and particles. Figure 2 represents a schematic sketch for a performance test of the TWS. The turbulent scrubber consists of a vertical inlet pipe at the center, through which the air and fly ash (as dust particles) enter the scrubber. The solid aerosol particle generator is connected to the inlet pipe to feed fly ash brought from a nearby thermal power plant at different concentrations. A portable aerosol spectrometer (portable dust monitor with 15 particle size channels, model 1.108, Grim, Germany) is connected to the inlet and outlet pipes of the scrubber to measure the particle concentrations and size distribution. A Testo 350 – S/XL (Germany) is used to measure the pressure loss across the scrubbing section of the turbulent scrubber. The three selected parameters that affect particle collection efficiency are the input concentration of particulate matter, the water level in the water reservoir of the TWS, and the flow rate of the air stream. The particulate scrubbing process in the turbulent wet scrubber was carried out for three different water levels filled through the opening of the nozzle from the water reservoir. The air stream at different flow rates (5.13 m /min and 7.62 m /min) and containing different input concentrations of particulate matter (230.84 mg/min, 110.89 mg/min, and 48.78 mg/min) was prepared with the aerosol feeder by adjusting feed rates to 10, 5, and 2, respectively. The air stream was then fed into the turbulent scrubber system. Fly ash was used to adjust concentrations of particulate matter in the air stream. The fly ash obtained from a coal power plant is a powder type with a spherical shape, and its major components are alumina (Al 2 O 3 ) and silica (SiO 2 ). The fly ash has an average diameter of 20 – 30 m m, an apparent density of 800 – 1000 kg/m 3 , and a true specific weight of 1.9 – 2.3. The dust-laden gas enters the scrubbing chamber by displacing the water in the vertical inlet pipe, and passes through a small rectangular nozzle of dimensions 760 mm  25 mm to a horizontal exit parallel to the liquid surface in the inner compart- ment of the scrubber. The water level of the scrubber is varied between 0 cm, 32 cm, 34 cm, and 36 cm from the bottom of the water reservoir. The lateral movement of the gas stream at the surface of the water for the first level (0 cm) scours the water surface and throws the particulate matter onto the deflectors, thereby creating agitation in the water column. At higher gas flow rates, the gas passing through the nozzle exits at high velocities, leading to vigorous agitation of the liquid and throw- ing of particular matter onto the curved deflector. The liquid climbs upward in the curved deflector and falls back to the bulk liquid, enclosing the gas in the form of bubbles. Thus, heavy turbulence is created by the gas stream in the stagnant water within the curved deflectors. For liquid levels of 32, 34, and 36 cm, the exit of gas from the nozzle leads to very high turbulence and results in a homogeneous gas and liquid mixture in the scrubber. This homogeneous gas and liquid mixture rises quickly and overflows above the deflectors to the rest of the chamber through the upper part of the deflector, as shown in Figure 2. Significant turbulence is created by gas bubbles formed in the rest of the chamber due to falling of the homogeneous medium. Thus, the entire scrubbing chamber is kept under turbulence and performs the particulate scrubbing process effectively. The downward-curved deflector prevents the entrainment of fine liquid droplets that arise due to bursting of the bubbles at the surface of the liquid. Turbulent wet scrubbers are high-energy scrubbers. High energy is utilized at the expense of gas- or liquid-phase energy to create turbulence in the scrubbing section for more efficient scrubbing. The turbulent scrubber used in the present study utilizes gas-phase energy in the form of high-velocity gas to displace the liquid in the inlet pipe and create turbulence in the scrubbing chamber. The pressure drop in the turbulent scrubber depends on the gas flow rates, the nozzle dimensions, and the liquid heads above the nozzle. The initial water level in the water reservoir was kept just below the nozzle (0 cm) and the pressure drop was measured for different gas flow rates. This pressure drop indicates the energy spent by the gas medium in scouring the liquid from the surface into films and droplets, and thereby creating turbulence for scrubbing. The pressure drop is due to the liquid head above the nozzle, and is measured at different gas flow rates for liquid levels of 32 cm, 34 cm, and 36 cm from the bottom of the reservoir. Figure 3 shows the effect of the gas flow rate on the pressure drop in the turbulent scrubber. As the gas flow rate increases, the pressure drop also increases. The pressure drop of fluid flowing across a system is directly proportional to the square of its velocity. Figure 3 also shows that there is a significant difference between the pressure drops across the turbulent scrubber with and without the liquid level above the nozzle. The pressure drop without the liquid is less than 20 mm H 2 O for the given gas flow rates, and it increases gradually along with the gas flow rate. The pressure drop across the nozzle is dominant compared to the liquid volume that is scoured upward in the deflector in the homogeneous form. Hence, the pressure drop is minimal compared to the pressure across the nozzle with the liquid head. The pressure drop for the system with a water head above the nozzle shows a different trend than the system with a pressure drop without a liquid head. The pressure drop increases steeply for gas flow rates up to 5 m 3 /min. Above 5 m 3 /min, the pressure drop increases gradually to reach a saturation level. The ratio of energy spent in creating turbulence is greater than at lower gas flow rates than at high flow rates, even though more liquid is kept under turbulence. Figure 4 shows the effect of the liquid level on the pressure drop. As the liquid head increases, the energy spent in homogenizing the liquid increases. Hence, there is a steep increase in the pressure drop with respect to the liquid level in the system. Figure 4 also reveals that the pressure drop increases along with the gas flow rate due to the hydrostatic head above the nozzle and frictional losses. In wet scrubbing, fine particles are scrubbed mainly under the influence of flux forces. In turbulent scrubbers, these flux forces aid in scrubbing the particulate matter. As the particle size (fly ash) increases from 0.65 μm, the efficiency of the turbulent scrubber increases and reaches almost 100% for particles around 5 μm (Figure 5). For a water level of 32 cm in the scrubber, the efficiency is around 43%. For water heads of 34 cm and 36 cm above the nozzle, the scrubbers reach efficiencies above 52% and 53%, respectively. There is a significant difference in particle scrubbing efficiency (ranging from 5% to 9%) for liquid heads between 32 cm and 34 cm in the scrubber for particles in the range between 0.65 μm and 1.0 μm, whereas for particles larger than 1.0 μm, the efficiency is almost the same for all liquid levels. The difference in percentage may be small, but it counts as the sizes of the particles are around the submicrometer level. Thus, liquid levels of 34 cm and 36 cm above the nozzle have a scrubbing efficiency more than 50% better for the smaller particles, even those ranging from 0.65 μm to 0.8 μm. Higher gas velocities lead to more turbulence in the scrubber, resulting in higher scrubbing efficiencies. Higher gas velocities also result in greater pressure drops in turbulent scrubbers. Figure 6 shows the particle removal efficiency of the turbulent scrubber at two different gas flow rates. For the higher gas flow rate, the efficiency of the turbulent scrubber is found to be predominant for submicrometer particles. Thus, there is a marked difference in the particle removal efficiency of the turbulent scrubber for particles smaller than 1 μm. The efficiency curves for the two gas flow rates merge with each other for larger particles, indicating that turbulence effects due to different gas flow rates do not affect the efficiency substantially in the case of particles larger than 2 μm. Thus, the contact between the gas and liquid for particle removal is established well for larger particles even at low gas flow rates, and the efficiency almost reaches 100%. A plot relating the pressure drop to the scrubbing efficiency gives insight into the energy spent in achieving the range of efficiencies for the given size distribution of particles. A correlation analysis for predicting particulate removal efficiency in the turbulent scrubber with respect to the energy spent was carried out by utilizing the contacting power theory approach. This approach predicts the size distribution of droplets or bubbles for different gas flow rates in the case of a turbulent scrubber in which the gas – liquid mixture is a homogeneous medium. Since the turbulent wet scrubber developed in this study falls between the droplet and bubble scrubber categories, the scrubbing efficiency can be directly associated with the energy spent in creating the turbulence in the system. Lapple and Kamack (1995) show that in wet scrubbing design, efficiency can be related to the energy expended in producing the actual gas – liquid contact. Thus, the contact power is the energy dissipated per unit volume of gas treated, which can be estimated from the total pressure drop in the turbulent scrubbing system. In the present turbulent scrubber, the energy spent in scrubbing is totally from the gas side. According to Semaru (1963), the efficiency ( ) of a wet scrubber is related to the number of transfer units, as shown in the ...
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Particulate matter in indoor environments has caused public concerns in recent years. The objective of this research is to explore the influence of radiators on particle size distributions and concentrations. The particle size distributions as well as concentrations above radiators and in the adjacent indoor air are monitored in forty-two indoor en...
Citations
... Furthermore, the water scrubber also meets the industrial level requirements for ammonia absorption, with a removal efficiency of up to 99.9% [20]. The water scrubber can even remove 100% of the small amount of solid particles [21]. With respect to the purification of sulfides, ammonia, and solid particles from crude syngas, the water scrubber can be compared to the Selexol process. ...
Biomass frequently constrains its widespread application due to its low economic efficiency. In this project, a new approach of biomass application was explored to reduce bio-syngas production cost. A model for the bio-syngas production from biomass gasification and bio-syngas purification (Selexol and water scrubbing) were studied. Based on the simulation results, we assessed the feasibility and viability of the project. Preliminary results showed that the bio-syngas production cost with Selexol (2.15 $/Nm3) is even higher than biomass used in power generation systems (equal to 1.58–2.21 $/Nm3). However, water scrubber was used as bio-syngas purification, the capital investment cost and bio-syngas production cost (1.34 $/Nm3) was significantly reduced. A sensitivity analysis was conducted on the bio-syngas price, which could be further reduced by various factors: biomass price, carbon taxes, and carbon credits. We assumed that bio-syngas was applied to natural gas pipeline, our analysis showed that the application of bio-syngas (2 to 10% content) to natural gas had little impact on natural gas properties: combustion value and price. The technology of water scrubber makes the applications of biomass-based fuels competitive.
... Some particulate matter has properties that can make them more difficult to capture by the system than the other [19]. Lee et al. [20] reported the nearly 100% removal efficiency of particulate matter larger than 1 µm, but depending upon the flow rate, the concentration of the dust-laden air stream, and the water level in the reservoir. In case our study, the combination treatment of water spray that can trap particle size from biomass emission and the coconut shell activated carbon that can absorb them, is effective in reducing the concentration of pollutant. ...
Wet packed scrubber system is one of the considering air pollution control technology. Its high removal efficiency has been recognized by many studies. However, different type of biomass sources and different type of wet scrubber may produce different desirable result. Considering on the emission of biomass burning type in Cambodia, this study aims to investigate the performance removal efficiency of particulate matter from biomass burning using wet packed scrubber system. The laboratory scale of wet packed scrubber system was designed to meet the current requirement of Cambodia’s biomass emission. One kilogram of each type of biomasses (wood, rice straw, mango seed and mango skin) were burning for 15 minutes in an open burning combustion chamber, designed of 1m×1m steel sample tray, by which the exhaust smoke was treated in the wet packed scrubber system. To study the optimization removal efficiency of the system, three scenarios are proposed. T0 is the condition of biomass burning without treatment. T1 is the condition that exhaust smoke is treated with spray water in the system. T2 is the condition that exhaust smoke is treated with spray water combined with the activated carbon as a packing material in the system. The result show that the removal efficiency is great in T3 scenario in mango seed sample. For other samples, the result was not conclusive as the removal efficiency in each sample was not consistency. The high removal efficiency of particulate matter in mango seed was 70.12% for PM 10 , 69.79% for PM 2.5 , and 71.53% for PM 1 . To enhance the quality of research, some aspects require further improvement to achieve the optimal outcome. Since biomass burning remains the main source of boiler energy, there is a need to develop more-cost effective and simpler emission control technologies that can diminish air contaminant before release.
... A deflector and baffle create water turbulence, allowing polluted air to flow through fluctuating water. This method can simultaneously increase the wettability of particles, agglomerate, and remove dust [12]. Meikap et al. [13] achieved a removal efficiency of 95% to 99% for particulate matter sizes of 0.1-100 µm in a modified multi-stage bubble column scrubber. ...
... Park [15] investigated the performance of a water turbulence scrubber for the removal of particle matter and found that particles more prominent than 1 µm were drawn efficiently (nearly 100%), depending on the flow rate, dust-laden air stream concentration, and the reservoir water level. Hence, spray columns and bubble column scrubbers are efficient in scrubbing particulate matter from effluent [12]. The objectives of this research were to determine the effect of each parameter and combination of them on PM2.5 removal efficiency, design an actual size wet scrubber in the bus shelter for the protection of pedestrians from roadside traffic pollution, ...
... 100%), depending on the flow rate, dust-laden air stream concentration, and the reservoir water level. Hence, spray columns and bubble column scrubbers are efficient in scrubbing particulate matter from effluent [12]. The objectives of this research were to determine the effect of each parameter and combination of them on PM2.5 removal efficiency, design an actual size wet scrubber in the bus shelter for the protection of pedestrians from roadside traffic pollution, and monitor the real-time PM2.5 concentration with an IoT system to calculate the accurate removal quantity of PM 2.5. ...
The removal efficiency of particulate matter of less than 2.5 microns (PM2.5) using an innovative wet scrubber tower with an IoT system for PM2.5 real-time monitoring was investigated. The PM2.5 used in this experiment was obtained from vehicle exhaust, specifically from running the diesel engine of a pickup truck with a range of PM2.5 with a concentration ranging from 50 µg/m3 to 500 µg/m3. Focused parameters related to PM2.5 were analyzed, such as the liquid-to-air ratio (it uses air because this device purifies PM2.5 for the airflow from the polluted ambient air), turbulence techniques enabled by the installation of a deflector and a baffle at the airflow inlet, water level fluctuation above the nozzle, spray nozzle size, and the type of packing material. The average PM2.5 removal efficiency was determined for each parameter relevant to the experiment. The results showed that increasing the liquid-to-air ratio increased the average PM2.5 removal efficiency, while the smaller droplet spraying water resulted in higher efficiency. The spray section achieved its highest efficiency at 58.63%, with a liquid-to-air ratio of 13.21 L/m3 and droplet size of 270 µm. The turbulence technique showed a higher potential for the removal of PM2.5, with an efficiency level of 71.56% at a water level of 150 mm. Moreover, the operation incorporates water spraying and turbulence induction, promoting higher removal efficiency, from 71.56% to 87.59%, at a water level of 150 mm and a liquid-to-air ratio of 9.03 L/m3. This condition resulted in an output concentration of PM2.5 less than 15 µg/m3, which meets the WHO’s guidelines for PM2.5 intensity. This cleverly designed wet scrubber tower can clean up to 13,320 m3 of air daily or remove up to 2,464 g of PM2.5 per day. No enhancement of PM2.5 removal efficiency was observed when two types of packing materials were used due to the formation of bigger droplets as the packing materials were passed through.
... Beyond a gas flow rate of 4.2 × 10 −3 Nm 3 s −1 , the collection efficiency did not improve with an increase in the gas flowrate but was instead limited due to coalescence which led to reduced bubble reformation. Lee et al. [47] reported that higher gas flowrates do indeed favored the collection of sub-micrometer particles smaller than 1 µm. Lee et al. [47] argues that the gas-liquid contact for effective particle collection is well established for larger particles even at low gas flow rates. ...
... Lee et al. [47] reported that higher gas flowrates do indeed favored the collection of sub-micrometer particles smaller than 1 µm. Lee et al. [47] argues that the gas-liquid contact for effective particle collection is well established for larger particles even at low gas flow rates. ...
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The growing production and application of engineered nanomaterials (ENM) in everyday products make their environmental discharge increasingly likely. This risk is particularly elevated at the end of the useful life of ENM. Given the lack of regulations targeting the safe disposal of ENM at end-of-life, nanowaste (NW) currently follows conventional waste management pathways even though their potential adverse effects on humans and the natural environment are well documented in the literature. Presently, preference exists for treating NW via centralized waste-to-energy systems such as incineration, given the potentially hazardous nature of NW. In this work, a Design of experiment (DOE) methodology—Box Behnken design was employed to optimize three independent operating parameters of a pilot-scale scrubber concerning the collection of nanoparticles under waste incineration conditions. The pilot-scale scrubber was designed and operated to be representative of a full-scale spray scrubber found in a hazardous waste incineration plant. The independent parameters studied are; the gas flowrate, the liquid flowrate and the droplet diameter. Six responses were chosen corresponding to the nanoparticle collection efficiencies at particle sizes in the diffusion-dominant, intermediate and impaction-dominant regions. The experimental results were analyzed for statistical significance using Design Expert software (V13). The DOE model by the software was then used to predict optimum operating conditions with maximum nanoparticle collection. A maximum nanoparticle collection efficiency of 41–60% was predicted by the DOE model under optimal conditions of a gas flowrate of 46.1 Nm³ h⁻¹, a liquid flowrate of 4.8 L min⁻¹, and a droplet diameter of 60 µm. These optimal conditions were determined by the highest liquid flowrate, the smallest droplet diameter, and a gas flowrate near the middle of the range studied. The results of the confirmatory experiments (43–62%) at the optimum combination agreed with the predicted data. The experimental results were also found to be in good agreement when compared to a mechanistic model based on impaction, Brownian diffusion and interception collection mechanisms.
Graphical Abstract
... Spray in the interior of the cyclone can promote the agglomeration of particles, which has been regarded as an effective and inexpensive method to deal with FPM [11]. In this device, the strong cyclonic flow, also called swirling flow, is introduced to increase the relative velocity of the dust particles and droplets [12], enhance the gas-liquid turbulence, increase the contact probability between the fine particles and droplets, and accelerate the aggregation and growth of the fine particles [13]. Bo W et al. [14] innovated a new fine particle removal technology-Cloud-Air-Purifying-which aggregates FPM and increases the particle size and found that the collection efficiency of FPM was improved compared to traditional gas cyclone. ...
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... Scrubbers are the most promising technology for providing SOx and PM emission solutions that comply with IMO requirements [3,6,7]. Wet scrubbers are the most common technologies today [152]. There are also hybrid aqueous scrubber systems, which combine open-loop and closed-loop systems. ...
With stricter IMO regulations on CO2 taking effect in 2023 and ambitious goals to reduce carbon intensity by 2030, the maritime industry is scrambling to clean up its act. Conventional methods and equipment are now being reevaluated, upgraded or completely replaced. The difference between a short-term fix and a long-term sustainable option is how flexible vessels will be to use new energy sources or technology as they become viable. The review discusses the recent literature on renewable energy sources, technical and operational strategies for new and existing ships, technology maturity, and alternative fuels. It is found that the IMO's targets can be met by combining two or three technologies, or via a radical technology shift which can provide innovative, high-efficiency solutions from an environmental and economic standpoint. It has also been noted that policies and enforcement are essential management instruments for mitigating the unfavourable environmental effects of marine transportation and directing the maritime industry toward sustainability on a regional, national, and international scale.
... The flue gas cleaning system in the municipal waste incinerator temperature is subject to the absorption/desorption of the materials applied to the wet scrubbing systems. This gas can also be produced during industrial processes such as waste pyrolysis and incineration [20][21][22] . Even though a major fraction of pollutants such as aerosols are generated by human activities originating from various industrial processes and combustion units, which pose major exposure threats for human beings. ...
The fine particles generated by the foundry industry are present in the atmosphere; they have an impact on the climate because of their influence on atmospheric radioactive phenomena. As a result of this scenario, there is a rising amount of legislation restricting the emission of pollutants from foundry industries and related businesses. In response to this situation, many researchers have concentrated on end-of-pipe technologies, one of which is the wet scrubber, which is a device that is primarily used in foundries to control pollution and is one of the devices that has been incorporated. The disadvantage of using this wet scrubber, on the other hand, is that it contributes to secondary pollution when it is used. In order to combat secondary pollution, a model of an enhanced wet scrubber system that incorporates a multi-sand filtering technology was developed. The performance of this redesigned wet scrubber system was evaluated with the use of computational fluid dynamics (CFD) software. In CFD, the Reynolds stress model was applied for simulation. The pressure magnitudes and velocity magnitudes are obtained by this simulation. The volume fraction of the dust was evaluated through the DPM approach. Because of the introduction of the filtration tank's computation, it was discovered that successful filtration was accomplished using sand filters, meaning that environmental chemicals and particles were totally filtered from 0.17 kg at the entrance to zero kg of particles at the outflow.
... The flue gas cleaning system in the municipal waste incinerator temperature is subject to the absorption/desorption of the materials applied to the wet scrubbing systems. This gas can also be produced during industrial processes such as waste pyrolysis and incineration [20][21][22] . Even though a major fraction of pollutants such as aerosols are generated by human activities originating from various industrial processes and combustion units, which pose major exposure threats for human beings. ...
The fine particles generated by the foundry industry are present in the atmosphere; they have an impact on the climate because of their influence on atmospheric radioactive phenomena. As a result of this scenario, there is a rising amount of legislation restricting the emission of pollutants from foundry industries and related businesses. In response to this situation, many researchers have concentrated on end-of-pipe technologies, one of which is the wet scrubber, which is a device that is primarily used in foundries to control pollution and is one of the devices that has been incorporated. The disadvantage of using this wet scrubber, on the other hand, is that it contributes to secondary pollution when it is used. In order to combat secondary pollution, a model of an enhanced wet scrubber system that incorporates a multi-sand filtering technology was developed. The performance of this redesigned wet scrubber system was evaluated with the use of computational fluid dynamics (CFD) software. In CFD, the Reynolds stress model was applied for simulation. The pressure magnitudes and velocity magnitudes are obtained by this simulation. The volume fraction of the dust was evaluated through the DPM approach. Because of the introduction of the filtration tank's computation, it was discovered that successful filtration was accomplished using sand filters, meaning that environmental chemicals and particles were totally filtered from 0.17 kg at the entrance to zero kg of particles at the outflow.
... Technical indicators of the second generation battery emulsifiers can be found in [10,11]. A turbulent wet scrubber is described in [12]. ...
... The existing gas dedusting system not only does not allow the utilization of waste heat from the gases but leads to a further reduction in the efficiency of the steam generator by about 3 up to 4%. Figure 1 shows a schematic diagram of the gas path after the steam generator with a battery emulsifier. wet scrubber (turbulent) [12]. ...
... The technical parameters of the turbulent wet scrubber include [12]: ...
The usage of wet methods for flue gas dedusting from coal-fired boilers is associated with significant heat losses and water resources. Widespread emulsifiers of the first and second generation are satisfactory in terms of flue gas cleaning efficiency (up to 99.5%), but at the same time do not create conditions for deeper waste heat recovery, leading to lowering the temperature of gases. Therefore, in the paper, an innovative modernization , including installing an additional economizer in front of the scrubber (emulsifier) is proposed, as part of the flue gas passes through a parallel bag filter. At the outlet of the emulsifier and the bag filter, the gases are mixed in a suitable ratio, whereby the gas mixture entering the stack does not create conditions for condensation processes in the stack.
... The ue gas cleaning system in the municipal waste incinerator temperature be subject to the absorption/desorption of the materials applied to the wet scrubbing systems. This gas can also be produced during industrial processes such as waste pyrolysis and incineration [20][21][22] . Even though a major fraction of pollutants such as aerosols are generated by human activities originating from various industrial processes and combustion units, which pose major exposure threats for human beings. ...
When fine particles generated by the foundry industry are present in the atmosphere, they have an impact on the climate because of their influence on atmospheric radioactive phenomena. As a result of this scenario, there is a rising amount of legislation restricting the emission of pollutants from foundry industries and related businesses. In response to this situation, many researchers have concentrated on end-of-pipe technologies, one of which is the wet scrubber, which is a device that is primarily used in foundries to control pollution and is one of the devices that has been incorporated. The disadvantage of using this wet scrubber, on the other hand, is that it contributes to secondary pollution when it is used. In order to combat secondary pollution, a model of an enhanced wet scrubber system that incorporates a multi-sand filtering technology was developed. The performance of this redesigned wet scrubber system was evaluated with the use of computational fluid dynamics software. Because of the introduction of the filtration tank's computation, it was discovered that successful filtration was accomplished using sand filters, meaning that environmental chemicals and particles were totally filtered from 0.17 kg at the entrance to zero kg of particles at the outflow.
