Gas Cleaning Research Articles

Integration and optimization of the after-treatments systems to reduce the acoustic footprint of the ships

Exhaust Gas Cleaning Systems (EGCS) such as scrubbers are mandatory and extensively used to abate SOx in exhaust gases when high sulphur content fuel oil is employed in the marine engine in order to comply with international ship emission regulations, both in new and existing ships. Currently, about 13% of bulker, container, and tanker ships have a scrubber installed, despite the fact that their installation on board is challenging due to their large dimensions to be fitted into the funnel and the complexity of the system, since the exhaust line must control both the chemical and acoustic emissions. In the presented work a combined FEM, CFD simulations and GA optimization methodology aimed at the integration of the abatement system, while optimizing the acoustic properties, is developed. The methodology is first assessed on an industrially-relevant scenario that involves the use of a Genset mock-up equipped with a reference Diesel Oxidation Catalyst (DOC) and a scrubber for the abatement of both NOx and SOx, showing that acoustic performances of the DOC are reliably modelled by the FEM-CFD methodology, which has a significantly reduced computational cost as compared to conventional CFD modelling of acoustic properties. The GA optimization is carried out to improve the DOC acoustic properties showing that it is possible to confer the silencing effect to the after-treatment systems, thus eliminating the traditional silencers from the exhaust line. This leads to a compact exhaust line that integrates the EGCS while maintaining efficient both the chemical pollution abatement capability, and silencing effects to guarantee full compliance (i.e., acoustic and chemical) with the international regulations.

Investigation on interaction effects of multiple factors on clean gas extraction: implementation of response surface methodology

AbstractGas-related disasters have become a major threat to mining safety of coal resources. Investigation into the optimization approach for inseam borehole gas extraction is important for improving extraction efficiency. By establishing control equations for coal seam deformation, porosity-permeability properties, and gas flow, effects of extraction time, initial gas pressure, initial coal permeability, and borehole diameter on gas flow pattern and effective extraction radius are analyzed. Based on response surface methodology and orthogonal experimental design, a regression analysis model of effective extraction radius and multiple influencing factors is established. Meanwhile, the interaction mechanism between effects of multiple factors is analyzed, thus identifying optimal parameters for gas extraction. Results show that effective extraction radius is positively correlated with initial permeability, extraction time, and borehole diameter, and negatively associated with original gas pressure. In terms of effect on effective extraction radius, those parameters could be ranked as follows: initial gas pressure, extraction time, initial coal permeability, then borehole diameter. Interaction between multiple factors could inhibit the impact of individual factors on extraction radius. An increase in initial gas pressure reduces the positive effect of permeability on extraction radius. Growing initial gas pressure inhibits the contribution of extraction time to effective drainage radius. Prolonged duration of extraction suppresses the positive effect of permeability on extraction radius. Interaction between initial gas pressure and initial permeability has the most significant influence on extraction radius. Results from orthogonal experimental design correspond to those of response surface methodology. These findings could provide guidance for dynamically adjusting drilling extraction parameters and improving gas-extraction outcomes.

Alveolar gradients in breath analysis. A pilot study with comparison of room air and inhaled air by simultaneous measurements using ion mobility spectrometry

Analyzing exhaled breath samples, especially using a highly sensitive method such as MCC/IMS (multi-capillary column/ion mobility spectrometry), may also detect analytes that are derived from exogenous production. In this regard, there is a discussion about the optimal interpretation of exhaled breath, either by considering volatile organic compounds (VOCs) only in exhaled breath or by additionally considering the composition of room air and calculating the alveolar gradients. However, there are no data on whether the composition and concentration of VOCs in room air are identical to those in truly inhaled air directly before analyzing the exhaled breath. The current study aimed to determine whether the VOCs in room air, which are usually used for the calculation of alveolar gradients, are identical to the VOCs in truly inhaled air. For the measurement of inhaled air and room air, two IMS, each coupled with an MCC that provided a pre-separation of the VOCs, were used in parallel. One device was used for sampling room air and the other for sampling inhaled air. Each device was coupled with a newly invented system that cleaned room air and provided a clean carrier gas, whereas formerly synthetic air had to be used as a carrier gas. In this pilot study, a healthy volunteer underwent three subsequent runs of sampling of inhaled air and simultaneous sampling and analysis of room air. Three of the selected 11 peaks (P4—unknown, P5—1-Butanol, and P9—Furan, 2-methyl-) had significantly higher intensities during inspiration than in room air, and four peaks (P1—1-Propanamine, N-(phenylmethylene), P2—2-Nonanone, P3—Benzene, 1,2,4-trimethyl-, and P11—Acetyl valeryl) had higher intensities in room air. Furthermore, four peaks (P6—Benzaldehyde, P7—Pentane, 2-methyl-, P8—Acetone, and P10—2-Propanamine) showed inconsistent differences in peak intensities between inhaled air and room air. To the best of our knowledge, this is the first study to compare simultaneous sampling of room air and inhaled air using MCC/IMS. The simultaneous measurement of inhaled air and room air showed that using room air for the calculation of alveolar gradients in breath analysis resulted in different alveolar gradient values than those obtained by measuring truly inhaled air.

SO3 removal rate and emission test of the limestone-gypsum wet desulfurization system for coal-fired power plants

This paper studies the SO3 removal ability of dual tower wet desulfurization (in series) and adopts a combination of on-site flue gas sampling and laboratory condensation control. A dual tower (series) supported boiler is used. The SO3 content in the original and clean flue gas of the dual cycle wet desulfurization device was measured, and the removal rate of SO3 of the device was measured. Desulfurization is calculated on the basis of the influence of unit electrical load, coal sulfur content, and desulfurization (raw material flue gas) inlet particle concentration on removal rate. This paper discusses and analyzes the SO3 and SO3 emission concentrations for SO3 removal rules in desulfurization systems. The results indicate that the total sulfur content of coal is relatively high, and the concentration of SO3 is relatively high. The traditional flue gas and net flue gas content in the dual tower wet desulfurization system (series) is relatively high. When burning sulfur-containing coal, there may be “blue smoke” in the flue gas. When the unit load changes between 182 MW and 350 MW, the SO3 removal rate of dual tower wet desulfurization (in series) is between 46.7% and 65.3%, with a net flue gas SO3 concentration of 16.0 mg/m3∼20.5 mg/m3. Due to equipment layout and other reasons, the SO3 removal rate of the primary tower is lower than that of the secondary tower. The removal rate of SO3 is also affected by the concentration of original smoke particles. Due to the condensation of SO3 on the particles and the dust removal of the adsorption tower, the higher the concentration of raw flue gas particles is, the higher the removal rate is. SO3 will be higher. The study also suggests the SO3 removal ability of double tower (series) and double ring wet desulfurization, which is better adapted to changes in load and coal. The next step is to explore the SO3 removal capacity of the dual tower system by optimizing its operating parameters. In addition, due to the arrangement of a desulfurization system after dust removal, it is impossible to control the SO3 source. Subsequent research can control the production of existing SO3 through coal distribution and combustion control.

Corrosion study of the clean fire extinguishing gas 2-BTP on typical magnesium alloy AZ80A in different temperature environments

2-bromo-3,3,3 trifluoropropene (2-BTP), as a substitute for halon fire extinguishing agent, is clean, environmentally friendly and low-toxicity. However, the potential corrosiveness increases the insecurity in 2-BTP applications. Therefore, the corrosion behavior of the agent to typical magnesium alloy material AZ80A was studied at different temperatures. On this basis, corrosion products and gaseous products were analyzed, and the corrosion mechanism of 2-BTP on AZ80A at 400 °C was explained. The result shows that the pyrolysis of 2-BTP produces C3∼C5 products and HF, which corrode AZ80A to produce MgF2, increasing the coupon mass and reducing the ultimate tensile strength. However, the corrosion product layer adheres tightly to the alloy surface and increases the corrosion resistance. Meanwhile, the substance increases the efficiency of the agent pyrolysis. The performance assessment of the 2-BTP was refined by this work.

Modeling and Cleaning Performance Optimization of Conical Filter Cartridge of Gas Turbine Intake Filter

Intake quality is crucial to gas turbines’ operation. The cartridge filter in the gas turbine intake system filters the gas and outputs a highly clean gas into the gas turbine, while pulse cleaning technology ensures the continuous and efficient operation of cartridge filters. While the current cylindrical pleated filter cartridge used in pulse cleaning usually suffers from insufficient upper cleaning, the conical pleated filter cartridge can effectively solve this issue by providing a greater upper cleaning area with significant application prospects. Despite the existing potential, research on conical filter cartridge cleaning performance is limited; thus, this paper aims to investigate the advantages of pulse cleaning using a conical filter cartridge via numerical simulation. Results demonstrate that while the conical filter cartridge enhances the cleaning strength, cleaning uniformity decreases slightly. To address this shortcoming, this paper innovatively proposes a combination of scattering nozzles and conical filter cartridges to explore the impact of the installation position of scattering nozzles on the cleaning. The modeling and cleaning performance analysis in our research illustrates that the optimal cleaning effect can be achieved under specific conditions when the scattering nozzle is installed parallel to the conical filter cartridge’s inlet. The research work in this paper provides a solution for optimizing the pulse cleaning performance of conical filter cartridges.

Membrane Electrolyzers for Hydrogen Production: From Catalyst Fundamentals to Devices

Water electrolysis powered by renewable sources such as wind or solar produces clean hydrogen gas, which is used for many industrial processes and will be essential in a future clean energy economy. Commercialized membrane electrolyzers use acidic proton exchange membranes (PEMs), which offer high performance but require the use of expensive precious-metal catalysts such as IrO2 and Pt that are nominally stable under the locally acidic conditions. Anion exchange membrane (AEM) electrolyzers in principle offer the performance of PEM electrolyzers with the ability to use earth-abundant catalysts and inexpensive bipolar plate materials. I will present our fundamental work in understanding the chemical and electrochemical processes in earth-abundant water-oxidation catalysts, including the use of integrated reference-electrode device architectures and cross-sectional materials analysis, as well as progress in building high-performance AEM electrolyzers. Baseline systems operate at 1 A·cm-2 in pure water feed at < 2 V at a moderate temperature of ~70 °C using either IrO2 or Co3O4 anode catalyst layers, Versogen TP-85 alkaline ionomers, and stainless-steel porous transport layers. These devices, however, degrade rapidly compared to PEM electrolyzers. The voltage profile corresponding to degradation has initial fast (~10 mV/h) and steady-state slow components (~1 mV/h), which we link to chemical and structural changes in the ionomer catalyst reactive zone. We further discover that dynamic Fe-based OER catalysts – that have world record performance in traditional liquid alkaline electrolyzer systems – perform poorly with enhanced degradation rates in alkaline membrane electrolysis, illustrating fundamentally different chemical design principles for OER catalysts. Lastly, I will discuss these processes in electrolyzer devices and in model systems, as well as present promising new chemical strategies we have developed to mitigate degradation and enhance performance using novel ionomers and electrode catalyst compositions and architectures.

Analysis of methods of managing the environmental safety of the navigation passage of ships of maritime transport

The requirements of the MARPOL international convention on ensuring the environmental performance of marine diesel engines in relation to the emission of sulfur oxides, as well as marine fuels during navigation passages of sea transport vessels in special ecological areas, are given. The use of scrubber cleaning of exhaust gases and the use of fuel mixtures, which include biodiesel fuel, are considered as methods that meet these requirements. The research was carried out on ships of the Bulker Carrier class with deadweight of 63,246 tons during the navigation transition between the ports of Northern Europe. One of the vessels used scrubber cleaning of exhaust gases as a method of environmental safety management. The other is the use of fuel mixtures, which include biodiesel fuel. Both vessels are equipped with a 5S60ME-C8.2 MAN-Diesel&amp;Turbo marine diesel engine as the main engine, and three 6EY18ALW Yanmar diesel engines as auxiliary engines. The ratio of sulfur oxides to carbon oxides – SO2/CO2 – was chosen as an indicator for evaluating the effectiveness of environmental safety management methods. This value was monitored and regulated by an automatic monitoring system. It was found that both methods meet the requirements of the MARPOL convention, namely, they will support the SO2/CO2 ratio in the range of 2.29–4.17 (when in special environmental control zones) and in the range of 6.46–20.83 (when in outside the zone of special environmental control). The use of environmental safety management methods increases energy costs for ensuring this process. When using exhaust gas scrubbing, additional power losses reach 237–278 kW. In the case of using a fuel mixture that includes biodiesel fuel, power losses amount to 18–20 kW. It has been experimentally confirmed that the use of a fuel mixture that includes biodiesel fuel is characterized by a lower level of environmental sustainability. At the same time, compared to the use of scrubber cleaning of exhaust gases, this method requires less energy consumption and is also characterized by simpler additional equipment. In this regard (and also taking into account that all the requirements of Annex VI MARPOL are provided), it is recommended as the main one to ensure the environmental safety of navigation passages of sea transport vessels.

Design, construction and validation of a simple, low-cost phi meter

The best correlation between the yields of the major toxicants in fire smoke and the fire condition is obtained by expressing the ventilation in terms of the equivalence ratio, phi. Phi meters allow this fuel-air equivalence ratio to be determined during a large-scale fire test. The original design used a platinum catalyst, a large furnace, and required pure oxygen. This work aimed to make a simple, low-cost device which could monitor the equivalence ratio during a large-scale fire test. The current design produces the same quality of measurement with a much smaller footprint and throughput. Benefits include enhanced portability, reduction in sample gas cleaning and drying requirements and lower cost. The work showed that normal furnace components (alumina and silica) provide suitably catalytic surfaces at 900 °C eliminating the requirement for platinum catalysts and the use of pure oxygen. The ISO/TS 19700 steady state tube furnace (SSTF) was used to validate the phi meter measurements as it can both pre-set and independently quantify the equivalence ratio during a test. Long sample collection times were overcome with a larger sampling pump and effluent being split between the phi meter furnace and the exhaust. It is hoped that this simpler, optimized apparatus will encourage more widespread use and lead to better prediction of smoke toxicity.

Research and Application Progress of Inverse Opal Photonic Crystals in Photocatalysis

In order to solve the problem of low photocatalytic efficiency in photocatalytic products, researchers proposed a method to use inverse opal photonic crystal structure in photocatalytic materials. This is due to a large specific surface area and a variety of optical properties of the inverse opal photonic crystal, which are great advantages in photocatalytic performance. In this paper, the photocatalytic principle and preparation methods of three-dimensional inverse opal photonic crystals are introduced, including the preparation of basic inverse opal photonic crystals and the photocatalytic modification of inverse opal photonic crystals, and then the application progresses of inverse opal photonic crystal photocatalyst in sewage purification, production of clean energy and waste gas treatment are introduced.

Ag-doped Monolayer and Bilayer Graphene for the Gas Sensor and Purifier of Industrial Oils

Graphene sensors have high sensitivity and selectivity and are commonly used to detect and clean oilbreakdownresulting gas contaminants. Silver impurities on Graphene sheet vacancywere simulated for Methane interaction with vacant Graphene layers, with and without silver impurities, based on density functional theory with Quantum ESPRESSO.PBEexchange–correlation function withGGAfunction and vdW-DF corrections were used. Analyzing adsorption energies revealed theeffects of the additives on Graphene, andshowedGraphene with silver impuritieswasa good option. Analyzes of methane(CH4/MVG,CH4/BVG,CH4/MVG_Ag,andCH4/BVG_Ag)show that adsorption strengths of the structures were the relationship MVG_Ag > BVG > MVG > BVG_Ag. AddingAgimpurity to the foil greatly increases the CH4 adsorption strength of MVG_Ag and decreases the adsorption strength of BVG_Ag. Due to CH4′s symmetry, orientation relative to Graphene makes no difference as it interacts with carbon atoms from any side.

Integration of adsorption based post-combustion carbon dioxide capture for a natural gas-fired combined heat and power plant

This paper proposes a continuous CO2 capture system for natural gas combined heat and power (CHP) facility and explores the potential of low-temperature vacuum-swing adsorption (VSA) process for post-combustion CO2 capture (PCC) in the context of carbon capture and storage (CCS). Although VSA has strong potential for efficient CO2 capture in district-scale energy systems, previous case studies have largely focused on high-emission coal combustion sources, making VSA application challenging for these conditions. We address this issue by theoretically designing a ready-to-operate flue gas cleaning process with CCS for a medium-sized 4.3 MW natural gas CHP operating in the local industry. Our in-depth analysis examines the most critical parts such as dehydration, involving condenser and temperature-swing adsorption (TSA), and CO2 capture via VSA. The conceptual design and performance of VSA are approached by developing a mathematical model to estimate the technology size and performance. This work shows that utilising a small fraction of heat recovered from CHP-generated flue gas is sufficient to supply the necessary heat for auxiliary units, and that using natural cooling water for dehydration effectively reduces moisture (87 vol%) and energy demand for final dehydration via TSA. Furthermore, it demonstrates that 4-step VSA consisting of 15 columns using zeolite 13X can separate CO2 with a desired purity of 90.4%, meeting the requirements for CO2 storage and transportation onshore, at a 15.6% recovery rate. The cost of achieving high CO2 purity without pre-pressurising the CO2-rich flue gas, while maintaining cycle simplicity, is discussed. Overall, our paper provides a comprehensive approach to retrofitting distract-scale power plants with CO2-lean emissions, presenting a ready-to-operate flue gas cleaning technology based on real operating conditions and technical restrictions, which can contribute towards decarbonisation.

Expanded Clay Production Waste as Supplementary Cementitious Material

Global warming stands as one of the most significant challenges facing our planet, primarily due to the substantial emissions of greenhouse gases into the atmosphere. Among the major contributors to these emissions is the cement industry, which ranks as one of the largest sources of CO2 pollutants. To address this issue, a potential solution involves partially substituting cement with alternative materials, particularly waste generated by other industries. The aim of this study was to investigate the opportunity of using an industrial waste which originates from the cleaning of flue gas in the production of expanded clay as a supplementary cementitious material. The influence of expanded clay kiln dust on the properties of Portland cement was estimated by XRD, thermal, calorimetry and compressive strength analysis. The expanded clay kiln dust was used as received and it was additionally thermally activated at 600 °C. It was determined that the original dust can be distinguished by average pozzolanic activity; meanwhile, the pozzolanic activity of additionally activated waste increased by one third. Portland cement was replaced with both types of waste in various proportions. It was found that the additive of the investigated waste accelerates the primary hydration of Portland cement, generates the pozzolanic reaction, and incites the formation of calcium silicate hydrates and hydrates containing aluminum compounds. The addition of up to 25 wt.% of activated expanded clay kiln dust leads to a higher compressive strength of samples of Portland cement.

DISTRIBUTION OF NATURAL RADIONUCLIDES IN ASHES, COLLECTED BY THERMAL POWER PLANTS ELECTROSTATIC PRECIPITATOR

Link for citation: Nazirov R.A., Vede P.Yu., Tarasov I.V., Zhuikov A.V., Sergunicheva E.M., Tolochko O.R. Distribution of natural radionuclides in ashes, collected by thermal power plants electrostatic precipitator. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 7, рр. 177-186. In Rus. Relevance. In the context of the global trend towards sustainable development, there is a problem of utilization of ash and slag waste from thermal power plants. The use of these wastes in the construction industry is of particular importance, due to the resource intensity of the production of building materials. Fly ash in the building materials composition can influence to a large extent the natural radioactivity of structures and increase the background radiation in the buildings. This is due to the fact that when coal combusting, fly ash is enriched with natural radionuclides. Purpose: to study the radioactivity of fly ash deposited on various fields of the electrostatic precipitator. Object: fly ash deposited on the fields of electrostatic precipitators from the combustion of Kansk-Achinsk brown coal in power boilers BKZ-420-140 PT-2. Methods. Content of Ra-226, Th-232 and K-40 was determined by gamma-spectrometric method, the value of the normalized indicator of specific effective activity for fly ash was calculated. The granulometric composition of the studied samples was determined by the method of laser diffraction analysis. Cluster analysis was used for statistical processing of test results. Results. The presence of two clusters in the content of natural radionuclides was established. In the first cluster, which has high radioactivity, the first and second fields of UGZ-4 electrostatic precipitators are combined, and in the second – the third and fourth fields. A correlation dependence was established between the numbers of fields of electrostatic precipitators, the size of ash particles, the content of Ra-226 and specific effective activity was established. No such dependence was found for Th-232. Conclusions. Particle distribution in the fields of electrostatic precipitators is multimodal. The nature of the distribution of each mode approaches the lognormal law. The content of radium and the value of the specific effective activity depend on the size of ash particles and are described by an exponential function. The highest content of Ra-226 is observed in the ashes deposited on the third and fourth fields of electrostatic precipitators, which indicates the enrichment of finer ash particles with this radionuclide. The conclusions obtained correspond to the well-known thesis about the increased radioactivity of ash particles that are not deposited by ash collection systems and enter the atmosphere together with flue gases. The proposed method for studying the distribution of natural radionuclides over the fields of electrostatic precipitators can be used to predict the radioactivity of particles that are not captured by the flue gas cleaning system and released into the environment.

Performance analysis of the cyclone separator with a novel clean air inlet installed on the roof surface

The study investigated the impact of implementing a new method of injecting clean air axially through the roof of the cylindrical section on the performance of cyclone separators. This secondary inlet was confined to a region common to both the vortex finder tube and the cylindrical section. The Stairmand high-efficiency cyclone was used as a reference model for comparison against the proposed design. For analysis, we made the potential use of CFD methods (based on LES and DPM models), along with the experimental and stereo-PIV research. Comparative analysis was carried out based on performance parameters (viz. the collection efficiency and pressure losses) and exploring flow physics inside the separator. Furthermore, six different values of clean gas inlet velocities were also considered to measure the relative performance. Conclusive results indicate that the new model increased the separation efficiency for all inlet velocities of the clean gas.

Biological Hydrogen Production from Urban and Industrial Wastewater

Biological hydrogen production is a process in which microorganisms convert organic matter into hydrogen gas. This renewable energy production method is of great interest as an environmentally friendly and sustainable energy source. Biological hydrogen production can be accomplished using different methods. The dark fermentation method is a process in which organic substances are converted into hydrogen gas by microorganisms in anaerobic (oxygen-free) environments. In this method, organic materials are subjected to the fermentation process and hydrogen gas is released. This process also offers a solution for waste management. Photo fermentation is a process in which photosynthetic organisms convert organic materials into hydrogen gas using light energy. The light is absorbed by the photosynthetic pigments and provides the necessary energy for hydrogen gas production. In this method, clean hydrogen gas can be produced using solar energy. Biological hydrogen production methods have several advantages. These include the use of renewable resources, low greenhouse gas emissions, waste management and low energy consumption. However, there are also some disadvantages depending on the methods, for example limited light access or the difficulty of obtaining the purity of hydrogen gas. Biological hydrogen production is a promising method to meet clean and sustainable energy needs. Continuous research and development studies continue to increase the efficiency of these methods and eliminate their disadvantages. In the future, with the more widespread use of biological hydrogen production methods, the diversity of clean energy sources will increase and environmental sustainability will be ensured.

Comprehensive Review on Thermal Performance Enhancement of Domestic Gas Stoves.

Cooking is a daily activity in every household, which consumes energy and produces pollution. Using clean gas fuels instead of traditional solid fuels will significantly reduce household air pollution. Although the use of clean-burning burners can reduce emissions, early domestic gas cookers had poor thermal performance. Currently, even small improvements in efficiency can result in significant energy savings due to the large number of domestic gas stoves in use. There has been a long history of research into the development of domestic gas stoves to improve performance and reduce energy consumption. Meanwhile, research into the use of hydrogen-enriched natural gas as a promising environmentally friendly fuel is increasing. In this paper, we perform a descriptive statistics and graphical visualization of network analysis by combining common databases with Bibliometrix. We also analyze the energy balance of domestic gas stoves and the influence of a single factor and multiple factors on stove performance. Then we provide a detailed overview of some research technologies in enhancing the thermal performance of gas stoves. We also discuss the research progress and application prospects for the use of hydrogen-enriched natural gas as a fuel in domestic gas stoves and identify areas for future research and issues that need attention.

Flue gas cleaning approach based on jet reactor prototype research

The motivations for developing innovative jet ejector scrubbers, which meet the contemporary requirements for reducing sulfur oxide emissions in marine engineering, are presented in this paper. The proposed jet ejector scrubber was equipped with a cylindrical mixing section. The selected operating conditions enabled the development of a mixing shock process that afforded favourable conditions for sulfur oxide absorption. The first series of experimental investigations were carried out on a laboratory scale for a 40-kW diesel engine equipped with jet ejector scrubbers at a sulfur mass content of 0.35% in the fuel. The tests were conducted for various applied motive nozzles, as well as a nominal mixing section length-to-diameter ratio (L/D) of 25. These tests confirmed the complete reduction of SO2 using the jet reactor, as well as the reduction of other chemical compounds in the exhaust gas without using additional filters, e.g., reduction of heavy metals and transition metals by 85–98% and 71–74%, respectively, and the removal of total organic carbon (TOC) from exhaust gas at a level greater than 46%. The second series of experiments investigated a diesel engine with a maximum power of 250 kW under marine operating conditions. In this case, the effect of the mixing section length was tested. For fuels with 1.0% and 1.5% sulfur mass contents, full reduction of sulfur oxides was obtained for various loads of the engine. A maximum SO2/CO2 ratio of 0.18 was obtained for the ejector with an L/D of 25 and an engine load of 200 kW. However, this is significantly lower than the required limit of 4.3 according to the IMO.

The Solent Strait: Water quality trends within a heavily trafficked marine environment, 2000 to 2020

This study presents an important long-term historical analysis of water quality in an internationally crucial waterway (the Solent, Hampshire, UK), in the context of increasing adoption of open-loop Exhaust Gas Cleaning Systems by shipping. The pollutants studied were acidification (pH), zinc, and benzo [a] pyrene, alongside temperature. We compared baseline sites to locations likely to be impacted by pollution. The Solent's average water temperature is slightly increasing, with temperatures at wastewater sites significantly higher. Acidification suggests a complex story, with a highly significant small overall increase in pH during the study period but significantly different values at wastewater and port sites. Zn concentrations have significantly reduced but increased in enclosed waters such as marinas. BaP showed no long-term trend with values at marinas significantly and consistently higher. The findings provide valuable long-term background data and insights that can feed into the upcoming review of the European Union's Marine Strategy Framework Directive and ongoing discussions about the regulation of, and future monitoring and management strategies for coastal/marine waterways.

Minimizing indoor infection risks with automotive nanofiltration and with laminar vertical flow

The knowledge about nanoaerosols, their potential health effects, their measurement, limitation and administrative-legal treatment has been developed in the last 3 decades in connection with the exhaust gas cleaning of the combustion engines. Nanofiltration, which has thus become known, almost completely eliminates nanoparticles with filters of high durability, high specific filtration areas, and reasonable costs. On the occasion of the Covid pandemic, NanoCleanAir experimentally proved that the viruses in an automotive filter substrate are separated as well as the combustion particles and are also deactivated. To minimize cross exchange of infectious aerosol, new attention must be paid to flow management in ventilated spaces. Digitized flow analysis has also received significant inspiration from engine technology in the past. This paper provides information on some basic investigations and gives valuable advice based on the experimental and numerical results of a retrofitted classroom.