Formaldehyde Emission Research Articles

Improving Indoor Air Quality: Using Polymate-777A as a Formaldehyde Scavenger to Decrease Formaldehyde Emission in Plywood Panels

Indoor air quality is significantly impacted by volatile organic compounds, with formaldehyde being a prominent concern due to its emission from wood composite products. Formaldehyde emissions from wood composite products is a big concern for the environment and people's health. This study focused at how effective a product called Polymate-777A, the additive used as a formaldehyde scavenger is in reducing the formaldehyde emissions from plywood. This study investigates the efficacy of Polymate-777A, a formaldehyde scavenger, in reducing formaldehyde emissions from plywood panels. Through a series of controlled experiments, it was evaluated the impact of varying concentrations of Polymate-777A on formaldehyde release, utilizing standardized testing methods to quantify emissions. Results indicate that the incorporation of Polymate-777A significantly reduces formaldehyde levels, enhancing the safety and environmental sustainability of plywood products. The Results revels that when 1.5% or more Polymate-777A was used as scavenger for plywood manufacturing, the plywood met the emission standards set by Japan and Europe for formaldehyde emissions. This study suggests that using Polymate-777A could be a good way to reduce formaldehyde emissions from wood products, which would be better for the environment and people's health.

Industrial boiler ash as an alternative for reducing formaldehyde emissions in medium-density fiberboards

ABSTRACT The study aimed to determine the feasibility of utilizing industrial boiler ash in the production of medium-density fiberboard, to reduce formaldehyde emissions without compromising physical and mechanical properties. Panels were manufactured with a density of 750 kg.m−³, employing 12% urea-formaldehyde resin and 1% paraffin emulsion, both with and without an ammonium sulfate-based catalyst. The production process involved cold pre-pressing followed by hot pressing at 180 °C and 40 kgf.cm−² for 10 min. The experimental plan varied in terms of the percentages of ash added to the adhesive (0%, 1%, 3%, and 5%) and the application of the catalyst. Both the properties of the adhesives and the panels were assessed. It became evident that both the catalyst and ash altered the adhesive properties. Regarding panel properties, the ash reduced formaldehyde emissions, but the catalyst had a more pronounced effect. The catalyst's impact on moisture content, bending strength (MOR), and modulus of elasticity (MOE) was observed, whereas ash positively influenced dimensional stability at 5% levels but adversely affected internal bond.

Facile and green preparation of carbonaceous material-based wood bio-adhesives using hydrochar from hydrothermal carbonization of glucose with or without acrylic acid/acrylamide

To address the issues of formaldehyde emission, mildew, and easy combustion of traditional wood adhesives, this paper, for the first time, reported formaldehyde-free plywood bio-adhesives using carbonaceous material (hydrochar) generated from hydrothermal carbonization (HTC) of glucose with or without acrylic acid (AA) and acrylamide (AM). The highest wet shear strength of bio-adhesives (BD-G/AA-180) was 1.32 MPa, which meets the Chinese national standard GB/T 9846-2015 (≥0.7 MPa). It was found that functional groups (–NH2 and –COOH) were abundant on the surface of hydrochar from co-HTC of glucose with AM or AA. The formation of covalent bonds (between components of bio-adhesives; between bio-adhesives and wood) via dehydration or esterification reaction was a key factor in improving wet shear strength during hot-press treatment. Unlike bio-adhesives developed from polysaccharides and proteins, these hydrochar carbonaceous material-derived bio-adhesives had excellent anti-mildew properties and flame resistance with help from ammonium polyphosphate. This work paves a new road to prepare green formaldehyde-free plywood bio-adhesives.

Study on Innovative Laminated Flooring with Resin-Impregnated Paper

A new type of laminated flooring decorated by resin impregnated paper (LWFWRIP) was designed, with the advantages of low formaldehyde emission, improved flame retardant, and high wear resistance. The structure of this new type of wood flooring is based on the ordinary laminated flooring, followed by a decorative layer of thin wood pieces, and then the transparent improved flame retardant, wear-resistant paper is added to the top. It is found that the hot-pressing temperature is the most significant factor affecting the adhesion of resin impregnated paper. The optimal hot-pressing parameters are selected as the hot-pressing pressure of 3.5 MPa, hot-pressing temperature of 180 °C, and hot-pressing time of 40 s. The new laminated flooring was improved with high flame retardant, high wear-resistant, combined with the conventional advantages of both solid wood composite flooring and reinforced wood flooring. The new laminated flooring decorated by resin impregnated paper has broad application prospects.

Enhanced formaldehyde oxidation of plywood using MnO2 nanoflowers supported on porous hydrothermal carbon at ambient temperature

MnO2 nanoflowers were supported on porous hydrothermal carbon via in situ loading and used for the catalytic oxidation of formaldehyde from plywood manufactured with UF adhesive. The prepared MnO2 had a δ-type structure. The use of hydrothermal carbon (Hcs) improved the dispersion of active components in the materials and provided space for the catalytic reactions. Hcs/MnO2 exhibited catalytic activity and stability during formaldehyde oxidation at room temperature. The formaldehyde removal efficiency reached 90.43 % in 30 min. The Hcs/MnO2 had more oxygen vacancies than the MnO2 catalyst, providing more abundant active substances such as -OH, O2-, O- and other active substances to promote the catalytic reaction. The effects of Hcs/MnO2 on the formaldehyde emission and the mechanical properties of plywood were investigated. The MOR, MOE and bonding strength of the Hcs/MnO2-loaded plywood with 9 % Hcs were 51.1 MPa, 2994 MPa, and 0.8 MPa, respectively. After 28 d of exposure, the formaldehyde emitted from the plywood treated with Hcs/MnO2 decreased to 0.023 mg/m3, which fulfilled the requirement for ENF grading. The controlled release of free formaldehyde from plywood by Hcs/MnO2 was reflected by changes in mass transfer and catalytic oxidation. The manganese oxides in the micropores of the wood reduced the diffusion coefficient of free formaldehyde and hindered migration through the substrate. Once the concentration of formaldehyde decreased to a certain level, it was degraded by Hcs/MnO2, thus removing formaldehyde from the source.

The Tula Industrial Area Field Experiment: Quantitative Measurements of Formaldehyde, Sulfur Dioxide, and Nitrogen Dioxide Emissions Using Mobile Differential Optical Absorption Spectroscopy Instruments

The Tula industrial area in Central Mexico comprises, among other industries, a refinery and a thermoelectric power plant. It is well known for its constant emissions of gases into the atmosphere and considered an important area where pollutants released into the atmosphere have an influence on local and regional air quality. During March and April 2017, a field campaign was conducted with the objective of quantifying formaldehyde (HCHO), sulfur dioxide (SO2), and nitrogen dioxide (NO2) emissions from this industrial area using mobile differential optical absorption spectroscopy (DOAS) instruments. Calculated average emissions of the Francisco Perez Rios Power Plant and the Miguel Hidalgo Refinery were 3.14 ± 2.13 tons per day of HCHO, 362.08 ± 300.14 tons per day of SO2, and 24.76 ± 12.82 tons per day of NO2. From the measurements conducted, the spatial distribution patterns of SO2, NO2, and HCHO were reconstructed, showing a dispersion pattern of SO2 and NO2 towards the southwest of the industrial complex, impacting agricultural and urban areas. Occasionally, and usually during the morning hours, SO2 and NO2 were dispersed towards the north or northeast of the industrial complex. In the case of HCHO, dispersion was observed towards the south and southeast of the industrial complex. The far-reaching implications of this study are that for the first time, formaldehyde emissions were quantified. In addition, a follow-up study was conducted regarding nitrogen dioxide and sulfur dioxide emissions from the Tula Industrial area.

A novel colorless flexible polymer aerogel with stable amine linkage enabled superior formaldehyde removal and multifunctional application

Massive formaldehyde emissions have seriously endangered environment and human health, while predictably polymer aerogel is a promising candidate for formaldehyde (FA) removal, whereas low FA adsorption capacity, high volume shrinkage, and mechanical brittleness restrict its further development. Herein, based on “rigid-soft combination” polycondensation strategy, trifunctional 1,3,5-benzenetricarboxaldehyde (BTC) and polyetheramine Jeffamine T403 are selected as building blocks to construct a novel amine-linked polymer aerogel (rBTA) with hierarchical micro-nano porous structure via mild sol-gel method and freeze-drying process. Stable amine linkages in rBTA are formed by NaBH4 reduction of imine bonds, improving acid/alkali resistance and chemical stability greatly, and creating numerous active amine sites for reaction with FA. Formation of robust 3D covalent network facilitates to simultaneously achieve ultra-low-shrinkage (5.4%), high specific compressive modulus (5.32 kN·m·kg-1), remarkable mechanical durability/fatigue-resistance, flexibility, and machinability. Benefiting from synergistic physical-chemical adsorption effect, FA adsorption capacity and removal ratio of rBTA reach as high as 459.84 mg·g-1 and 97.87%, respectively. Colorless rBTA is further ground into powders for preparing polyoxymethylene (POM)/rBTA composite without affecting its color and formaldehyde emission amount at 60/230°C effectively decreases by 66.87%/79.55%. Furthermore, rBTA exhibits hydrophobicity, low thermal conductivity, and high solar reflectance, being successfully applied in emulsion separation, thermal insulation, and energy-efficient buildings fields.

Study on the Thermal Condensation Mechanism of Dehydrogenated Polymer (DHP) and Glucuronic Acid.

The preparation of traditional wood-based panels mostly uses adhesives such as urea-formaldehyde resin and phenolic resin, which not only consumes petrochemical resources but also releases formaldehyde, posing potential health risks to the human body. Lignin, a natural adhesive in plant cells, is characterized by high reactivity, and it is expected to aid in the development of a new generation of green formaldehyde-free adhesives. However, current studies of lignin adhesives have revealed that while strides have been made in reducing formaldehyde emissions, its residual presence remains a concern, an issue which is compounded by inadequate water resistance. Dehydrogenated Polymer (DHP) has a lignin-like structure and good water resistance, offering a new option for the development of formaldehyde-free adhesives. In this paper, DHP and glucuronic acid were reacted with each other in a simulated hot-pressing environment to obtain DHP-glucuronic acid complex, and then the structure of the complex was characterized by infrared nuclear magnetic resonance to verify whether DHP can be efficiently connected with hemicellulose components under hot-pressing conditions. The results showed that the thermal condensation reaction of DHP and glucuronic acid can generate ester bonds at the Cα position in a simulated hot-pressing environment. This paper explores the thermal condensation mechanism of DHP and glucuronic acid, which is helpful for understanding the bonding process between adhesives and components of wood-based panels in the hot-pressing process, and provides key theoretical support for the design of more sustainable lignin adhesives.

Evaluation of Some Physico-Mechanical Properties and Formaldehyde Emission of Ecological Chipboards Produced from Annual Residue Plant Stems

Evaluation of Some Physico-Mechanical Properties and Formaldehyde Emission of Ecological Chipboards Produced from Annual Residue Plant Stems

VOC species emissions from gasoline direct injection (GDI) and port fuel injection (PFI) vehicles combusting different gasoline

Reducing VOCs can effectively reduce the concentration of PM2.5 and O3. Different gasoline compositions can impact the VOC species emitted by GDI and PFI vehicles. In this study, VOC species emitted from GDI and PFI vehicles combusting gasoline with different compositions (i.e., G1-market #92 gasoline, G2-high alkane gasoline, and G3-high heavy aromatic gasoline) were tested, and the influence of VOC species on O3 formation were investigated. The results indicated that the GDI vehicle consistently exhibited higher VOC emissions than the PFI vehicle in combusting three types of gasolines. The presence of short-chain alkanes and alkenes in the exhaust of combusting G2 and ethyne among the aromatics of combusting G3 resulted in higher VOC emissions from combusting G2 and G3 than from combusting G1 in the GDI vehicle. High alkane gasoline exhibited larger reductions of VOC emissions in the PFI vehicle but increased the proportions of propene, 1-butene, and ethyne emissions. High heavy aromatic gasoline increased the proportion of ethyne emissions in the GDI vehicle and increased the proportion of toluene, formaldehyde, and propane emissions in the PFI vehicle. The overall emission variation of ozone formation potential (OFP) was similar to those of VOC emissions. Alkene (C2-C6), monocyclic aromatic hydrocarbons (MAHs) and aldehydes had high contribution to O3 formation. Further research is needed to optimize fuel upgrading for GDI vehicles to ensure effective emission reduction. The results would help reduce vehicle emissions and provide support for achieving synergistic prevention and control of PM2.5 and O3 pollution.

Thermal stability and thermal degradation kinetics of urea-formaldehyde resin modified by sodium lignosulfonate

ABSTRACT In this paper, an environmentally friendly urea-formaldehyde resin (UF) was prepared by using sodium lignosulfonate (SL) as a modifier. According to the basic properties of the resin, the strength of the plywood and the formaldehyde emission, the optimum addition amount of SL was determined. At the same time, the thermal curing and thermal degradation behavior of the resin were studied. The results show that the addition of SL can significantly reduce the formaldehyde emission of plywood. When the addition amount of SL was 1%, the wet bonding strength and formaldehyde emission of SL-modified UF (SL-UF) resin were 1.28 MPa and 0.35 mg·L−1, respectively, which were 23% higher and 71% lower than those of UF resin. Moreover, the initial curing temperature of SL-UF resin is lower, but the thermal curing activation energy is higher. SL also has a significant effect on the thermal degradation performance of UF resin. SL is a modifier that can effectively improve the performance of UF.

A detailed methodology for estimating health-related hazards of workplace exposure to indoor formaldehyde vapours

A comprehensive risk assessment method was applied to examine the risks associated with airborne formaldehyde occupational exposure among hospital laboratory staff. The method assessed exposure levels and health impacts by integrating area and personal air sampling, biological monitoring, and self-reported health data. Samples were collected from 74 workplaces across various departments using NIOSH method 3500 and were analyzed via UV-vis spectrophotometry. The data showed significant differences in exposure levels between departments (p≤0.05) and confirmed the efficacy of the method in identifying risk differences. Despite average personal exposure levels being measured lower than occupational limits, individual assessments indicated that some participants surpassed these limits, emphasizing the necessity of personal monitoring for workers with higher risks. The high prevalence of respiratory symptoms, such as cough and wheezing among staff, indicated the need for further investigation and targeted interventions. Although estimated cancer and non-cancer risks were within safe thresholds, the study emphasized the importance of continuous exposure monitoring and the implementation of effective control measures in hospital laboratory departments with formaldehyde emission. This integrated method improved the reliability and generalizability of formaldehyde exposure risk assessments and aided in the development of safe occupational health practices.•The method integrated personal and area sampling with advanced calibration for precise occupational exposure evaluation in laboratories.•The method used of biomarkers to assess formaldehyde absorption in the body estimating both cancerous and non-cancerous health risks associated with occupational exposure.•Addressed traditional method limitations and integrated risk components to improve data reliability for workplace safety and health risk management.

A framework for natural resource management with geospatial machine learning: a case study of the 2021 Almora forest fires

BackgroundWildfires have a substantial impact on air quality and ecosystems by releasing greenhouse gases (GHGs), trace gases, and aerosols into the atmosphere. These wildfires produce both light-absorbing and merely scattering aerosols that can act as cloud condensation nuclei, altering cloud reflectivity, cloud lifetime, and precipitation frequency. Uttarakhand province in India experiences frequent wildfires that affect its protected ecosystems. Thus, a natural resource management system is needed in this region to assess the impact of wildfire hazards on land and atmosphere. We conducted an analysis of a severe fire event that occurred between January and April 2021 in the Kumaun region of Uttarakhand, by utilizing open-source geospatial data. Near-real-time satellite observations of pre- and post-fire conditions within the study area were used to detect changes in land and atmosphere. Supervised machine learning algorithm was also implemented to estimate burned above ground biomass (AGB) to monitor biomass stock.ResultsThe study found that 21.75% of the total burned area burned with moderate to high severity, resulting in a decreased Soil Adjusted Vegetation Index value (> 0.3), a reduced Normalized Differential Moisture Index value (> 0.4), and a lowered Normalized Differential Vegetation Index (> 0.5). The AGB estimate demonstrated a significant simple determination (r2 = 0.001702) and probability (P < 2.2 10−16), along with a positive correlation (r ≤ 0.24) with vegetation and soil indices. The algorithm predicted that 17.56 tonnes of biomass per hectare burned in the Kumaun forests. This fire incident resulted in increased emissions of carbon dioxide (CO2; ~ 0.8 10−4 kg carbon h−1), methane (CH4; ~ 200 10−9 mol fraction in dry air), carbon monoxide (CO; 2000 1015 molecules cm−2 total column), and formaldehyde (HCHO; 3500 1013 molecules cm−2 total column), along with increased aerosol optical thickness (varying from 0.2 to 0.5).ConclusionsWe believe that our proposed operational framework for managing natural resources and assessing the impact of natural hazards can be used to efficiently monitor near-real-time forest-fire-caused changes in land and atmosphere. This method makes use of openly accessible geospatial data that can be employed for several objectives, including monitoring carbon stocks, greenhouse gas emissions, criterion air pollution, and radiative forcing of the climate, among many others. Our proposed framework will assist policymakers and the scientific community in mitigating climate change problems and in developing adaptation policies.

Bioinspired ‘phenol-amine’ cross-linking and mineral reinforcement enable strong, tough, and formaldehyde-free tannic acid-based adhesives

Conventional tannin-based adhesives have limitations such as formaldehyde emission, inadequate strength and toughness, which restrict their practical applications. Herein, motivated by the natural mechanisms of ‘phenol-amine’ cross-linking and biomineralization, a strong, tough and formaldehyde-free tannic acid-based adhesive was prepared by using all-biomass feedstock. The adhesive was prepared by integrating tannic acid-Zn nanoparticles (TA-Zn NPs), hyperbranched polyamide-grafted dialdehyde chitosan (HPCS), and triglycidylamine (TGA), which formed the fundamental cross-linking network of the prepared adhesive through a Schiff base reaction. The dry and wet bonding strength of the adhesive achieved 1.91 MPa and 1.54 MPa, respectively. The presence of sacrificial bonds such as N…Zn complexation and hydrogen bonding in the adhesive significantly enhance its toughness with a debonding work of 0.595 J. Benefiting from the exceptional antimicrobial properties of TA, chitosan, and Zn2+, the prepared adhesive demonstrated excellent mechanical properties even after being stored in a humid environment for 2 days, with wet and dry bond strength of 1.42 MPa and 1.10 MPa, respectively. Moreover, this adhesive exhibited remarkable resistance to mildew for a duration of 30 days and emitted lower volatile organic compounds compared to other synthetic and biomass adhesives. This innovative bionic strategy holds great potential in enhancing the toughness and functionality of adhesives and composites.

A quantitative comparison of economic viability, volatile organic compounds, and particle-bound carbon emissions from a diesel engine fueled with biodiesel blends

Despite the environmental advantages of biofuel blends, detailed studies on emissions of polycyclic aromatic hydrocarbons (PAHs), n-alkanes, and particle-bound carbon from diesel engines, particularly when fueled with biodiesel, remain limited. This study addresses these gaps by analyzing biodiesel blends from neem, linseed, and jatropha oils produced via mechanical extraction and assessing their impact on volatile organic compounds and particle-bound carbon emissions in diesel engine. Economic evaluations of production costs, engine modifications, and payback periods are also conducted. The result shows that jatropha biodiesel exhibits a calorific value of 35.7 MJ/kg, while neem biodiesel shows superior oxidative stability due to its low iodine value. Additionally, linseed biodiesel displays favorable cold flow properties due to its high density and cetane value. Compared to D100, the N10 and N30 blend notably reduced high molecular weight PAH emissions by 10.7 % and 38.4 %, respectively, with the N30 blend achieving a remarkable 76 % reduction in formaldehyde emissions. Conversely, the J10 blend increased specific PAHs, while the J30 blend reduced PAHs by 21.3 %. Both L10 and L30 blends showed reduced naphthalene emissions, with the J30 blend notably reducing elemental carbon (EC) by 31.4 %, although organic carbon (OC) slightly increased. In contrast, the N30 blend decreased both EC and OC emissions, demonstrating a dose-dependent relationship between biodiesel concentration and emissions reduction. Overall, Jatropha biodiesel blends offer the best balance of economic efficiency and emission reductions, resulting in shorter payback periods and lower carcinogenic risks. Neem and linseed blends also provide environmental benefits but with varying economic implications, highlighting the trade-offs between production costs and long-term sustainability.

Supporting Circular Economy Principles by Recycling Window Frames into Particleboard.

The aim of the study was to identify limiting factors for reusing wood through the recycling of window frames by conducting research under fully controlled conditions. The research involved manufacturing new window frames, seasoning them, and then shredding them into wood particles to prepare a three-layer particleboard. The proportion of wood particles in recycling was 0, 5, 10, 25, 50, and 100 parts by weight of the manufactured particleboard. Mechanical property tests were conducted: modulus of elasticity (MOE) and modulus of rupture (MOR), internal bond (IB), screw withdrawal resistance (SWR), and physical properties: density profile (DP), thickness swelling (TS) after water immersion, water absorption (WA), as well as formaldehyde emission and total volatile organic compound (TVOCs) tests. The research indicates a significant potential for utilizing wood from this sector of the wood industry, particularly considering variants with a higher proportion of recycled wood. MOR and MOE results are most promising for variants above 50 parts by weight of recycled wood. Based on the results obtained, it is clear that the production process should be improved or the raw material modified to enhance the internal bonding of particleboard, as these results were the weakest. Thus, recycled wood from window joinery has the potential to be reincarnated as particleboard, which continues to be widely used in their production.

The Influence of Various Modifications of Hazelnut Shell Flour as Potential Filler in Plywood Technology.

This study investigates the potential of utilizing hazelnut shells (HS) as an innovative filler in three-layer plywood technology, addressing the growing need for sustainable, high-performance materials. Traditional plywood production relies on adhesives enhanced with various fillers to improve physical, mechanical, and operational characteristics. This research explores using native, chemically modified, and activated carbon derived from hazelnut shells as fillers in urea-formaldehyde (UF) resin. The produced plywood's mechanical properties, water absorption, and formaldehyde emissions were thoroughly analyzed. Key findings demonstrate that incorporating 10 part by weight (pbw) native hazelnut shell flour significantly enhances the modulus of rupture (MOR) to 138.6 N mm-2 and modulus of elasticity (MOE) to 13,311 N mm-2. Chemically modified hazelnut shell flour achieves optimal results at 5 pbw, while activated carbon from hazelnut shells, even at 1 pbw, markedly improves bonding strength (2.79 N mm-2 referred to 0.81 N mm-2 for reference sample without filler added). Notably, activated carbon effectively reduces formaldehyde emissions (2.72 mg 100 g-1 oven dry panel referred to 3.32 mg 100 g-1 oven dry panel for reference samples with 10 pbw filler) and improves water resistance, indicating better further dimensional stability and lower environmental impact. The study also shows that excessive filler content negatively affects strength parameters, confirming the importance of optimizing filler concentration. These results highlight the potential of hazelnut shells as an eco-friendly alternative filler in plywood production, contributing to waste valorization and environmental sustainability. This study supports the practical application of hazelnut shell fillers, promoting a circular economy and reducing reliance on traditional, less sustainable materials, thus providing a valuable solution for the wood composite industry.

Incorporation of Nano-Zinc Oxide as a Strategy to Improve the Barrier Properties of Biopolymer-Suberinic Acid Residues Films: A Preliminary Study.

Finishing coatings in the wood-based composites industry not only influence the final appearance of the product but also serve to protect against fungi and molds and reduce the release of harmful substances, particularly formaldehyde and volatile organic compounds (VOCs). Carbon-rich materials, such as those derived from birch bark extraction, specifically suberin acids, can fulfill this role. Previous research has demonstrated that adding suberin acid residues (SAR) at 20% and 50% by weight significantly enhances the gas barrier properties of surface-finishing materials based on poly(lactide) (PLA) and polycaprolactone (PCL), particularly in terms of total VOC (TVOC) and formaldehyde emissions. This study aims to explore whether these properties can be further improved through the incorporation of nano-zinc oxide (nano-ZnO). Previous research has shown that these nanoparticles possess strong resistance to biological factors and can positively affect the characteristics of nanofilms applied as surface protection. The study employed PLA and PCL finishing layers blended with SAR powder at 10% w/w and included 2% and 4% nano-zinc oxide nanoparticles. The resulting blends were milled to create a powder, which was subsequently pressed into 1 mm-thick films. These films were then applied to raw particleboard surfaces. TVOC and formaldehyde emission tests were conducted. Additionally, the fungal resistance of the coated surfaces was assessed. The results showed that PLA/SAR and PCL/SAR composites with the addition of nano-zinc oxide nanoparticles exhibited significantly improved barrier properties, offering a promising avenue for developing biodegradable, formaldehyde-free coatings with enhanced features in the furniture industry. Furthermore, by utilizing SAR as a post-extraction residue, this project aligns perfectly with the concept of upcycling.

Methane slip and other emissions from newbuild LNG engine under real-world operation of a state-of-the art cruise ship

Liquefied natural gas (LNG) use as shipping fuel has increased in recent years. While LNG results in lower carbon dioxide (CO2) emissions as well as benefits in terms of air pollutants, the slip of unburned methane, the main component of LNG, has remained a concern. In this study, methane together with other climate warming agents, CO2 and black carbon (BC), as well as other emission compounds were characterized from 4-stroke low-pressure dual fuel engine on-board a newly build cruise ship utilizing LNG as well as marine gas oil (MGO). The brake specific methane slip was found to vary according to engine load, being 2.3–3.0 g/kWh at 54–80% loads, but increasing to 10 g/kWh at 25% load and 21 g/kWh at 12% load. The LNG combustion also resulted in higher formaldehyde emissions compared to MGO, but reduction in formaldehyde levels was observed over the SCR catalyst present in the exhaust line of the dual-fuel engine, without urea injection, suggesting it may provide a pathway for formaldehyde mitigation. In terms of particle emissions, LNG use reduced particle mass (PM) by 87–93% and BC by 94–99% compared to MGO combustion. Non-volatile particle number above 23 nm (PNnv,>23nm) and 10 nm (PNnv,>10nm) were reduced by 88–97% and 97–99%, except at lowest engine load where PNnv,>10nm increased by 26% compared to MGO utilization. When total greenhouse gas (GHG) emissions including CO2 and BC were considered, LNG use resulted in 13–15% lower GHG at high loads, but the benefit was undermined by the escaping methane at low load conditions. Following the engine activity profile during 8-months of vessel operation on the Mediterranean suggested, however, that in a diesel-electric cruise ship, low load conditions are used mainly during arrivals and departures from harbors, as the engine was operated at loads above 40% for 90% of the operation time. Weighted emission factor, representing the actual engine operation, resulted in methane slip of 2.8 g/kWh or 1.7% of the fuel use, which is below the value considered in the FuelEU Maritime. The results suggest that load specific methane slip, together with engine load profile should be considered when evaluating methane slip on vessel or fleet level.

Effect of pre-injection strategy on the reduction of exhaust emissions from n-pentanol/biodiesel engine

N-pentanol can be used as an additive component of biodiesel to achieve NOx and soot emission reductions while improving the low-temperature fluidity of biodiesel. This paper investigates the mechanism of pre-injection strategies (pre-main injection interval and pre-injection ratio) on the emission characteristics of n-pentanol/biodiesel engines. It extends the study to investigate the effect pattern of pre-injection strategies on formaldehyde emissions. The results show that the emission characteristics of the n-pentanol/biodiesel engine can be effectively improved by using a pre-injection strategy compared to a single injection. With the pre-main injection interval increase, the in-cylinder combustion stability was improved, and the generation of NOx and soot was effectively suppressed. Compared to a single injection, a pre-main injection interval of 15 °CA resulted in a 15.38 % decrease in CA50 and an 18.32 % increase in IMEP. Meanwhile, the increase of the pre-main spray interval broke the trade-off relationship between NOx and soot, and when the main pre-spray interval was increased from 15 °CA to 30 °CA, Soot and NOx generation were reduced by 27.46 % and 21.30 %, respectively. As the proportion of pre-injection increases, the center of gravity of combustion is shifted forward, the combustion exotherm is more concentrated, and the soot emission is significantly reduced. When the percentage of pre-spray was increased from 0 % to 20 %, CA50 decreased by 19.23 %, IMEP increased by 1.32 %, and soot generation decreased by 61.02 %. When the proportion of pre-spray was increased from 15 % to 20 %, CH2O emissions were reduced by 14.81 %.