Performance Of Scrubber Research Articles

A lithium-air battery and gas handling system demonstrator.

The lithium-air (Li-air) battery offers one of the highest practical specific energy densities of any battery system at >400 W h kgsystem-1. The practical cell is expected to operate in air, which is flowed into the positive porous electrode where it forms Li2O2 on discharge and is released as O2 on charge. The presence of CO2 and H2O in the gas stream leads to the formation of oxidatively robust side products, Li2CO3 and LiOH, respectively. Thus, a gas handling system is needed to control the flow and remove CO2 and H2O from the gas supply. Here we present the first example of an integrated Li-air battery with in-line gas handling, that allows control over the flow and composition of the gas supplied to a Li-air cell and simultaneous evaluation of the cell and scrubber performance. Our findings reveal that O2 flow can drastically impact the capacity of cells and confirm the need for redox mediators. However, we show that current air-electrode designs translated from fuel cell technology are not suitable for Li-air cells as they result in the need for higher gas flow rates than required theoretically. This puts the scrubber under a high load and increases the requirements for solvent saturation and recapture. Our results clarify the challenges that must be addressed to realise a practical Li-air system and will provide vital insight for future modelling and cell development.

Cobalt/nickel purification by solvent extraction with ionic liquids in millifluidic reactors: From single-channel to numbered-up configuration with solvent recycle

This work describes the continuous separation of cobalt and nickel by solvent extraction in a numbered-up millifluidic system (1 mm ID) using Cyphos IL 101 (C101) as extractant, which is recycled. A dilution of 50 vol% C101 in p-cymene was chosen as the optimal trade-off between extraction performance and hydrodynamic properties of the solvent. The effects of channel length (20–100 cm), flow rate (1–2.5 mL min−1) and temperature (20–70 °C) were investigated on the extraction, scrubbing and stripping performance in a single-channel system. Subsequently, the developed manifold structure (five parallel reactors) was benchmarked against the single-channel system, which displayed a maldistribution of only 1% and performed equally well as the single-channel system. Then, a continuous separation process of one extraction and two countercurrent stripping stages was executed for 6 h with the proven manifold. A cobalt and nickel purity of, respectively, 99.7 and 97.7 % were achieved at a rate of 5 mL min−1. Stable slug flow was observed in the entire system throughout the operating period.

Analysis of a marine scrubber operation with a combined analytical/AI-based method

This paper describes the performances of a marine SO2 absorption scrubber installed onboard a large Ro-Ro cargo ship. The study is based on the reconstruction of an extensive dataset from one-year continuous monitoring of the scrubber’s performances and operating conditions. The dataset has been interpreted with a conventional analytical, physical-mathematical, model for absorbers' rating and its combination with an Artificial Intelligence (AI) one. First, the analytical model has been used to provide a deterministic mathematical framework for the interpretation and the prediction of the scrubber’s performances in terms of absorbed SO2 molar flow and SO2 concentration at the scrubber exit. Then, data mining and AI techniques have been applied to develop an Artificial Neural Network able to predict the error between the actual SO2 concentration at the scrubber exit and the corresponding analytical model predictions. The final result is a combined model providing superior robustness and accuracy in the prediction of the scrubber performance while preserving a rationale for process design and operation. This interesting outcome suggests that the development of combined, or hybrid, Analytical/AI models can be a reliable and cost-effective way to improve chemical engineers' ability to design and control marine scrubbers, as well as other chemical equipment.

Assessment of a Multi-Stage Wet Scrubber Performance Based on Characteristics of Scrubbing Solution

This paper presents the wet scrubber performance on acid gas absorption based on pH and conductivity measurements. The waste combustion system comprised of a CFB combustor in which mainly plastics waste was loaded into the riser (15 cm ID x 1.5 m long). The scrubbing experiments were conducted using a two-stage wet scrubber used as air pollution control device. The performance of the wet scrubber system was assessed by studying the changes in the pH and conductivity. The scrubbing solution was prepared using lime. The optimum lime concentration was obtained from bench experiments, giving an initial pH of up to 13. The scrubbing solution samples were collected from the solution tanks after every 2 minutes for 40 minutes. The scrubbing solution flow rate ranged from 0.53 to 0.95 L/s while the gas flow rate from the blower was kept constant at 16 m/s. It was observed that the pH of the scrubbing solution for both stages decreased to neutral range with increasing operation time. The decrease in pH and conductivity was initially faster before increasing slightly due to deposition of fly ash. It was concluded that the multi- stage wet scrubber is capable of removing toxic acid gas and particulate matter

Comparison of open- and closed-loop operating strategies for exhaust gas scrubbing in marine applications: Modeling and sea-trial data

A model of a hybrid marine engine exhaust gas scrubber is constructed using sea-trial data and a chemical process simulator. The model can describe the performance of the scrubber under both open-loop and closed-loop operation. Predictions for solubility and reaction equilibria are validated using published data. The model results are consistent with the sea-trial data. Sensitivity analyses are conducted to determine the effect of various operating parameters on the scrubbing performance for both open-loop and closed-loop operation.

Structured packing improves wet scrubbing of airborne molecular contaminants in cleanroom make-up air units

The use of wet scrubbing to remove airborne molecular contaminants in cleanroom make-up air units has economic benefits and good application prospects. Still, problems with this method include low removal efficiency and large water consumption. To improve scrubbing performance, we built a full-scale scrubbing experiment platform using SO2 as the removal object. In addition, we applied structured packing in the scrubbing process to enhance the mass transfer between gas and liquid, and we tested the wet scrubbing removal efficiency and pressure drop under a variety of operating conditions. Results showed that under the condition of double-row spraying only, the SO2 removal efficiency increased with increasing liquid-gas ratio. The efficiency ranged from 57% to 83.9% and the pressure drop ranged from 6 to 15 Pa. After adding structured packing, the removal efficiency under different liquid-gas ratios improved significantly. Improvement was more apparent, ranging from 72.2% to 86.2%, when the liquid-gas ratio was low. The pressure drop also increased, ranging between 59 Pa and 100 Pa. In addition, we changed the packing thickness and the number of stages, and found that when the packing thickness was 0.2 m and the two-stage spacing was 0.15 m, removal efficiency improved up to 89.7%. The research results are significant for optimizing wet scrubbing performance and, at the same time, have practical engineering value for controlling the concentration of airborne molecular contaminants in the cleanrooms.

Possibility of military service-regeneration of LiOH for submarines and improvement in CO2 scrubbing performance of LiOH canisters

Possibility of military service-regeneration of LiOH for submarines and improvement in CO2 scrubbing performance of LiOH canisters

An Effect of Zeolite Size on Performance of Dry Scrubber in Tar Removal of Biomass Derived Syngas

Increasing attention on the use of biomass derived syngas as internal combustion engine fuel, impacts on rising the demand of the scrubber for tar removal of the syngas. Wet scrubber is been used widely for this purpose. However, the liquid adsorbent containing tar may harmful when exposes to the environment. Thus to encounter the problem, the present work proposes the use of dry scrubber with zeolite as an adsorbent. The work aims to develop a simple and low cost zeolite scrubber and investigate and effect of zeolite size on performance of the scrubber for tar removal of syngas from biomass gasification. The result shows that zeolite size is proportional to specific area, heat transfer rate, and scrubber’s effectiveness. The highest scrubber’s effectiveness of 0.25 is obtained for the smallest zeolite size, i.e. 30 mm.

Studies on Venturi Scrubber Performance and Efficiency- A Review

Studies on Venturi Scrubber Performance and Efficiency- A Review

Studies on Venturi Scrubber Performance and Efficiency- A Review

Studies on Venturi Scrubber Performance and Efficiency- A Review

Studies on Venturi Scrubber Performance and Efficiency- A Review

Studies on Venturi Scrubber Performance and Efficiency- A Review

Performance of wet scrubbers to remove VOCs from rubber emissions

Poor performance of wet scrubbers in rubber processing plants due to breakthrough of specific volatile organic compounds (VOCs) causes odour impact events. The performance of wet scrubbers in the rubber drying process to remove VOCs was investigated in order to determine the responsible odorants. VOC emissions originating at the inlet and outlet of wet scrubbers were quantified using gas chromatography-mass spectrometry/olfactometry (GC-MS/O). Critical VOCs were identified alongside seasonal and daily variations of those VOCs. Altogether, 80 VOCs were detected in rubber emissions with 16 classified as critical VOCs based on their chemical concentration, high odour activity value (OAV) and unpleasant odour. Volatile fatty acids (VFAs) were the dominant VOCs with seasonal variations affecting emission composition. Results demonstrated the ineffectiveness of the wet scrubbers to mitigate odorous VOCs whereas the removal of some VOCs could be improved based on their polarity and solubility. It was found that there is a correlation between the wet scrubber performance and VFAs concentration in the emissions. The findings demonstrated that combining quantitative and sensory analyses improved accuracy in identifying odorous VOCs, which can cause odour annoyance from rubber processing. A VOC identification framework was proposed using both analyses approaches.

AN EFFECT OF SPRAY CONFIGURATION AND ADSORBENT MATERIAL ON PERFORMANCE OF THE SPRAY SCRUBBER IN THE DOWNDRAFT GASIFIER-ENGINE SYSTEM

The work aims to investigate an effect of spray configuration and adsorbent material on performance of wet scrubber in removing tar gravimetric in producer gas. The scrubber is installed at small scale downdraft gasifier-engine system and the tests are conducted in two sections. Firstly, the scrubber is tested using water adsorbent at various spray flow configurations to the producer gas flow (cross flow, counter flow, mixed flow). Secondly, the scrubber is tested using adsorbent of cooking oil and waste of engine lubricant at cross flow spray configuration. The performance of the scrubber investigated are temperature profile, log mean temperature difference, heat transfer rate, and tar removal effectiveness. For spray configuration test, the result shows that cross spray configuration (CrS) has the optimum performance. The CsS scrubber has the highest LMTD, heat transfer rate, and tar removal efficiency among others. The values are 29.8°C, 7.84 kW, and 0.43, accordingly. Meanwhile, the test using different adsorbent indicates adsorption property of the adsorbent plays an important rules in tar removal effectiveness of the scrubber. The removal effectiveness of the scrubber for using adsorbent of water, cooking oil, and engine lubricant are 0.43, 0.12, and 0.60, respectively.

Environmental and economic issues concerning the use of wet scrubbers coupled to bagasse-fired boilers: a case study in the Brazilian sugarcane industry

For decades, wet scrubbers have been used to control particulate matter (PM) emitted by bagasse-fired boilers in the sugarcane industry. This choice was justified by their acceptable performance in meeting environmental standards, the abundance of water resources, and the fact that their operation was simpler and less expensive than other dry cleaning operations. However, the progressive tightening of PM emission limits, as well as the need for more rational water and wastewater management in these applications, has changed this aspect of the industry. Despite the extensive technical literature on wet scrubbers, the lack of up-to-date indicators of their performance in sugarcane industries has prevented the optimization of wet scrubbing processes. This paper clearly shows that the use of wet scrubbers can result in significant water and heat losses, as well as high operating costs for wastewater treatment stations (WTSs). Mass and energy balances were determined for a typical ethanol-sugar plant operating in Brazil, which is the world's largest sugarcane producer. The key boiler and scrubber performance indicators were evaluated experimentally over the course of a crop season and were compared to the legal particulate emission and water quality requirements in Brazil. The boiler processed an average of 114.8 t/h of bagasse containing 46.8% moisture and generated 4.75 t of gas and 28.2 kg of PM for each ton of dry burned bagasse. Of the total PM (ash and soot), 68% was collected as dry material in the grate, heat exchangers, and multicyclone; 25% was collected in the wet scrubber; and 7% was emitted to the atmosphere, in compliance with the Brazilian standards. The operation of the WTS linked to the gas cleaning system was inefficient, using 70% of the water to convey the dry PM retained in the boiler, heat exchangers, and multicyclone and only 30% to operate the wet scrubber. Evaporation caused the loss of 10.5% of the scrubbing water to the atmosphere. The transportation of moist cake (7.9 t/h, 78% wb) for disposal in fields resulted in significant fuel costs and water losses. The operation of the WTS accounted for 62% of the total capital expenditure of the cleaning system, while the wet scrubber accounted for only 38%. This work provides updated performance indicators and alternatives for optimizing a gas cleaning system to promote more rational water and wastewater management and savings for the sugarcane sector.Graphic abstractRequired collection efficiency for bagasse boilers based on the inlet PM concentration and emission limits imposed in Brazil, China, and most countries

Dry scrubbing of gaseous HCl and SO2 with hydrated lime in entrained mixing reactor

The simultaneous dry scrubbing of gaseous HCl and SO2 by hydrated lime in the entrained mixing reactor has been studied at condition of simulating waste incineration flue gas. The entrained mixing reactor combining a numerical optimized entrained mixing up flow reactor with a rectifier for homogeneous flue gas mixing flow distribution were developed as reaction chambers for the dry scrubbing of gaseous HCl and SO2 with hydrated lime powders. The dry scrubbing performance of this technology was experimented at the pilot scale entrained mixing reactor with 0.3 m in diameter of lower part chamber, 1.29 m in diameter of upper part chamber and 6.0 m in total height. Three kind of hydrated lime powders with different surface area and pore volume were injected with carrier compressed air into the reaction chamber for absorption of acid gaseous. The experimental conditions were the following: reaction temperature 180 °C, gas flow rate 1800Nm3/h and HCl and SO2 concentration in inlet gas 250 ppm, respectively, giving different values for the ratio the amount of fresh hydrated lime and acid gaseous concentration at the inlet of reaction chamber and that corresponding to the stoichiometric molar ratio (SR). The gaseous HCl and SO2 removal efficiencies ranged from 89 to 99% and 87 to 99% respectively. The best performance of dry scrubbing was obtained for high surface area and pore volume of the hydrated lime. Increased the surface area and pore volume of hydrated lime improved the removal performance of the gaseous HCl and SO2 as well as the solid reactant conversion. The concentration of HCl and SO2 at the downstream of bag filter was measured to predict the absorption of gaseous HCl and SO2 on the surface of bag filter.

Venturi Scrubber Development and Implementation to Industry Scale

Emission limits are tightening globally. This affects also smelting industry and more efficient gas cleaning solutions are needed for ferroalloys production in submerged arc furnaces (SAF). In SAF’s, gas cleaning is commonly conducted with wet scrubbers, such as Venturi Scrubber. Advantages of venturi scrubbers are safety and robustness. However, meeting current emission limits with conventional wet scrubbers is challenging. Therefore, a development program was launched for improving the performance and gas cleaning efficiency of Venturi Scrubbers. In the development program, the effect of an additional cleaning stage (auxiliary venturi) and droplet separation on the scrubber performance was studied with Computational Fluid Dynamics (CFD) studies and pilot-scale test scrubbers. Test results indicated that the auxiliary venturi increased dust removal efficiency and enhanced pressure generation. Furthermore, the effective droplet separation turned out to be a key factor to the effective gas cleaning. Results and findings from the development work and the pilot-scale tests were implemented and validated in the industry scale. Operational experiences and emission measurements, from industry, indicated that enhanced performance and lower emissions were achieved with the improved scrubber design. Future challenges like decreasing gas handling water consumption, energy recovery and handling SOx, NOx and other harmful emissions will be discussed also.

A Hierarchical Scrubbing Technique for SEU Mitigation on SRAM-Based FPGAs

The SRAM-based field-programmable gate array (FPGA) is extremely susceptible to single event upsets (SEUs) on configuration memory which can lead to soft error and malfunction of the circuit. Facing the ever-growing number of configuration bits in modern FPGAs, traditional scrubbing is getting harder to find errors in time, resulting in mismatching between the SEU sensitivity and scrubbing performance. This article proposes a hierarchical scrubbing technique that makes full use of the SEU sensitivity based on the adaptive mean time to detect (MTTD) for each frame. It distinguishes the configuration frames with multipriority and uses different scrubbing methods for different priorities. Also, a model has been built for solving the MTTD allocating problem and enabling an effective scrubbing when SEU occurrence. Moreover, the corresponding hardware architecture is supported and the fault injection-based evaluation on a Xilinx Kintex-7 FPGA is done. The result shows that it can improve mean upsets to failure from 1.56 × to 146.93 × , which is proportional to the mean time to failure (MTTF) improvement.

Optimization of SO2 and NOx sequential wet absorption in a two-stage bioscrubber for elemental sulphur valorisation.

Flue gases contain SO2 and NOx that can be treated together for elemental sulphur recovery in bioscrubbers, a technology that couples physical-chemical and biological processes for gaseous emissions treatment in a more economic manner than classical absorption. Sequential wet absorption of SO2 and NOx from flue gas is thoroughly studied in this work in a two-stage bioscrubber towards elemental sulphur valorisation pursuing reuse of biological process effluents as absorbents. The optimal operating conditions required for SO2 and NOx absorption in two consecutive spray absorbers were defined using NaOH-based absorbents. Overall, removal efficiencies of 98.9% and 55.9% for SO2 and NOx abatement were obtained in two in-series scrubbers operated under a gas contact time of 1 and 100 s, and a liquid-to-gas ratio of 7.5 and 15 L m-3, respectively. Higher NOx removal efficiency to clean gas emission was obtained by oxidants dosing in the absorber for NOx absorption. High NaHCO3 concentration in a two-stage bioscrubber effluent was exploited as alkaline absorbent for flue gas treatment. The performance of scrubbers using an absorbent mimicking a reused effluent exhibited the same removal efficiencies than those observed using NaOH solutions. In addition, the reuse of bioprocess effluent reduced reagents' consumption by a 63.7%. Thus, the two-stage bioscrubber proposed herein offers an environmentally friendly and economic alternative for flue gas treatment.

Numerical Modeling of a Flooded-Bed Dust Scrubber Integrated into a Longwall Shearer

Dust generation and its dispersion in a longwall mine pose significant health and safety issues. The concern is prominent at both the working face, where coal excavation exposes workers to high dust concentrations, and also in the return, where float dust accumulates. To address this issue, researchers at the University of Kentucky designed and fabricated a flooded-bed dust scrubber integrated into a full-scale physical model of a longwall shearer. This mock-up was installed in the longwall test gallery at the Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health (NIOSH). A full-factorial experiment was designed to measure the effectiveness of the scrubber on dust capture. Test results indicated dust reduction of up to 57% in the return airways. This paper presents the development of a computational fluid dynamics (CFD) model and its validation by comparing the simulation results against the experimental results. The CFD simulations show good agreement with experimental results with differences between + 6.9 and − 9.7%. The validated CFD model was used further to predict the scrubber performance under additional operating conditions, resulting in a dust reduction of up to 66.5%. With this level of success, the scrubber concept can be a game changer for the mining industry, and it can be utilized to improve health and safety in longwall mines.

Wet Scrubber for Coal Combustion with The Use of Textile Wastewater Feeding

Coal combustion emission contains the acidic gas SO2. Meanwhile, textile wastewater contains high alkaline. This study inspects the performance of scrubber from boiler using coal fuel with textile wastewater as feeding. The wastewater was collected from an equalization tank. We adopted SNI standard for emission measurements at the outlet. The reduction of acidic gas pollutants concentration was 31–78%, while the operating temperature was observed at 83–190 °C. This study ascertains that using textile wastewater as scrubber feeding has mutual benefits i.e. at wastewater treatment and air pollution control devices in situ.