Fugitive Emissions Research Articles

Estimating Greenhouse Gas Emissions from Hydrogen-Blended Natural Gas Networks

Methane is a significant contributor to anthropogenic greenhouse gas emissions. Blending hydrogen with natural gas in existing networks presents a promising strategy to reduce these emissions and support the transition to a carbon-neutral energy system. However, hydrogen’s potential for atmospheric release raises safety and environmental concerns, necessitating an assessment of its impact on methane emissions and leakage behavior. This study introduces a methodology for estimating how fugitive emissions change when a natural gas network is shifted to a 10% hydrogen blend by combining analytical flowrate models with data from sampled leaks across a natural gas network. The methodology involves developing conversion factors based on existing methane emission rates to predict corresponding hydrogen emissions across different sections of the network, including mainlines, service lines, and facilities. Our findings reveal that while the overall volumetric emission rates increase by 5.67% on the mainlines and 3.04% on the service lines, primarily due to hydrogen’s lower density, methane emissions decrease by 5.95% on the mainlines and 8.28% on the service lines. However, when considering the impact of a 10% hydrogen blend on the Global Warming Potential, the net reduction in greenhouse gas emissions is 5.37% for the mainlines and 7.72% for the service lines. This work bridges the gap between research on hydrogen leakage and network readiness, which traditionally focuses on safety, and environmental sustainability studies on methane emission.

Anesthetic Gases: Environmental Impacts and Mitigation Strategies for Fluranes and Nitrous Oxide

Anesthetic gases represent a small but significant portion of the environmental impact of health care in many countries. These compounds include several fluorocarbons commonly referred to as “fluranes”. The fluranes are greenhouse gases (GHG) with global warming potentials in the hundreds to thousands and are also PFAS compounds (per- and polyfluorinated alkyl substances) according to at least one definition. Nitrous oxide (N2O) is sometimes used as an adjunct in anesthesia, or for sedation, but has a significant stratospheric ozone depletion potential as well as GHG effects. Reducing emissions of these compounds into the environment is, therefore, a growing priority in the health care sector. Elimination or substitution of the highest impact fluranes with alternatives has been pursued with some success but limitations remain. Several emission control strategies have been developed for fluranes including adsorption onto solids, which has shown commercial promise. Catalytic decomposition methods have been pursued for N2O emission control, although mixtures of fluranes and N2O are potentially problematic for this technology. All such emission control technologies require the effective scavenging and containment of the anesthetics during use, but the limited available information suggests that fugitive emissions into the operating room may be a significant route for unmitigated losses of approximately 50% of the used fluranes into the environment. A better understanding and quantification of such fugitive emissions is needed to help minimize these releases. Further cost–benefit and techno-economic analyses are also needed to identify strategies and best practices for the future.

Adsorption of Methane–Nitrogen mixtures with flexible Zeolitic Imidazolate Framework-7 (ZIF-7)

ZIF–7 is a pressure–regulated flexible metal–organic framework with a notably lower admission pressure for CH4 relative to N2, making it highly-prospective for curbing fugitive emissions of methane. Here, the separation of CH4 from N2 by an improved variant of ZIF–7 was studied over a range of pressures, temperatures, and compositions using multiple complementary techniques. Pure gas adsorption isotherms measured from (283 to 323) K at up to 16 MPa reveal this variant of ZIF-7 exhibits 50–60 % higher adsorption capacities for both CH4 and N2 in the large–pore phase than previous ZIF–7 samples. Binary mixture adsorption isotherms from dynamic column breakthrough experiments were consistent with those predicted from pure–gas isotherms using Ideal Adsorbed Solution Theory. Methane uptake increased significantly when the pore phase transition pressure for the mixture was reached, while the uptake of nitrogen remained small. Consequently, the equilibrium CH4-over–N2 selectivity of ZIF-7 is always larger than 5.5 and can increase to around 9, significantly above that of conventional adsorbents. Further characterisation showed the rate of the adsorption on ZIF–7 initially decreases as the pore phase transition begins before it increases significantly. Raman spectra acquired at various pressures along the adsorption isotherms revealed changes in certain vibrational modes associated with the structural change. Collectively, these observations indicate that the conceptually simple gating mechanism often used to describe the pore phase transitions in ZIF-7 in fact depends on interactions between the guest molecules and the adsorbent framework that continue to operate once the material is in the large–pore state.

First Investigation of Long-Term Methane Emissions from Wastewater Treatment Using Satellite Remote Sensing

Wastewater treatment (WWT) contributes 2–9% of global greenhouse gas (GHG) emissions. The noticeable uncertainty in emissions estimation is due in large part to the lack of measurement data. Several methods have recently been developed for monitoring fugitive GHG emissions from WWT. However, limited by the short duration of the monitoring, only “snapshot” data can be obtained, necessitating extrapolation of the limited data for estimating annual emissions. Extrapolation introduces substantial errors, as it fails to account for the spatial and temporal variations of fugitive emissions. This research evaluated the feasibility of studying the long-term CH4 emissions from WWT by analyzing high spatial resolution Sentinel-2 data. Satellite images of a WWT plant in Calgary, Canada, taken between 2019 and 2023, were processed to retrieve CH4 column concentration distributions. Digital image processing techniques were developed and used for extracting the time- and space-varying features of CH4 emissions, which revealed daily, monthly, seasonal, and annual variations. Emission hotspots were also identified and corroborated with ground-based measurements. Despite limitations due to atmospheric scattering, cloud cover, and sensor resolution, which affect precise ground-level concentration assessments, the findings reveal the dynamic nature of fugitive GHG emissions from WWT, indicating the need for continuous monitoring. The results also show the potential of utilizing satellite images for cost-effectively evaluating fugitive CH4 emissions.

Putting biomonitors to work: native moss as a screening tool for solid waste incineration

Solid waste incineration (SWI) can release numerous air pollutants although the geographic reach of emissions is not routinely monitored. While many studies use moss and lichens for biomonitoring trace elements, including around SWIs, few investigate the complex, multi-element footprint expected from SWI emissions. This study develops using native moss as a screening tool for SWI while also informing community concerns about an aging incinerator in rural Oregon, USA. Trained community volunteers helped collect 36 composite samples of epiphytic moss (Orthotrichum s.l.) along a 32-km transect from the SWI. We used ICP-MS to measure 40 elements in moss, including 14 rare earth elements (REEs) previously unexplored for SWI. We compared the elemental signatures of samples with an emissions profile for SWI and modeled relationships between element concentrations and distance from the facility using nonparametric regression. The chemical signatures in moss pointed to SWI as a source, potentially through both stack and fugitive dust emissions. The strongest models described farther-dispersing elements, including mercury and cadmium (xR2 = 0.65 and 0.62, respectively), and suggested most deposition occurs within 5 to 10 km of the facility. Elements often associated with soil and dust, like arsenic and chromium, exhibited localized peaks within 0.2 km of the incinerator (xR2 = 0.14–0.3). Three novel elements—cesium and REEs europium and gadolinium—also showed promise as atmospheric tracers for SWI. Gadolinium, a contrast reagent for MRIs, could reflect medical waste incineration by the facility. We include additional analysis and discussion to help stakeholders use results effectively.

Optimizing Methane Recovery for Fuels: A Comparative Study of Fugitive Emissions in Biogas Plants, WWTPs, and Landfills

How accurate are current estimation methods for fugitive methane emissions in methane-producing facilities, and how do they vary across biogas plants, wastewater treatment plants (WWTPs), and landfills? Based on this, the hypothesis posited in this study is that current methods significantly underestimate methane emissions, particularly in WWTPs and biogas plants, due to limitations in accounting for recovered methane and the reliance on general parameters such as the oxidation factor. To test this, a comparative analysis was carried out involving 33 biogas plants, 87 WWTPs, and 119 landfills in the Iberian Peninsula, comparing officially recorded data with estimates derived from our own calculations. Our findings confirm the lack of precision in current emission estimation methods, particularly for WWTPs and biogas plants, where factors like the omission of recovered methane lead to underreporting. This study highlights that WWTPs emit the largest amount of methane due to their organic material processing, exceeding emissions from landfills and biogas plants. In contrast, methods for estimating emissions in landfills are found to be more reliable. The results suggest that improving calculation methodologies, especially for WWTPs and biogas plants, as well as enhancing leak monitoring and methane recovery systems, is crucial to reducing the environmental impact of methane-producing facilities.

From Waste to Strength: A Comprehensive Review on Using Fly Ash in Composites with Enhanced Mechanical Properties

This article explores the diverse applications of fly ash (FA), a by-product generated during the combustion of coal. The introductory segment thoroughly comprehends the origins, composition, and widespread occurrence of FA. FA, which comprises an estimated 38% of worldwide power generation, frequently encounters disposal and storage obstacles on account of its classification as non-hazardous waste in the majority of countries. The environmental issues linked to the dispersal of FA are underscored in the problem statement, which further emphasizes the urgency for sustainable alternatives. Due to the fugitive emissions and potential health hazards associated with metal melting in FA, it is critical to investigate novel applications and disposal techniques immediately. Environmental sustainability is a primary focus of research, with the development of synthetic FA composites being one such alternative. The analysis presents significant findings that underscore the wide-ranging applications of FA. These applications include its utilization as a filler in composites, as well as its incorporation into cement and geo-polymerization processes. Notably, (10-20) wt. % Nano-FA enhances epoxy-based composites, showcasing remarkable improvements in tensile strength, flexural strength, and impact resistance. In thermoplastic composites, substantial enhancements occur within the (5–10) wt. % FA range, but exceeding optimal ranges weakens matrix-fiber interaction, leading to diminishing returns. The article emphasizes the criticality of FA in improving the mechanical and thermodynamic characteristics of substances, specifically within the domain of composites. The investigation into FA nanoparticles, including their processing techniques and surface treatments, unveils encouraging prospects for enhancing material characteristics.

Addressing Low-Cost Methane Sensor Calibration Shortcomings with Machine Learning

Quantifying methane emissions is essential for meeting near-term climate goals and is typically carried out using methane concentrations measured downwind of the source. One major source of methane that is important to observe and promptly remediate is fugitive emissions from oil and gas production sites but installing methane sensors at the thousands of sites within a production basin is expensive. In recent years, relatively inexpensive metal oxide sensors have been used to measure methane concentrations at production sites. Current methods used to calibrate metal oxide sensors have been shown to have significant shortcomings, resulting in limited confidence in methane concentrations generated by these sensors. To address this, we investigate using machine learning (ML) to generate a model that converts metal oxide sensor output to methane mixing ratios. To generate test data, two metal oxide sensors, TGS2600 and TGS2611, were collocated with a trace methane analyzer downwind of controlled methane releases. Over the duration of the measurements, the trace gas analyzer’s average methane mixing ratio was 2.40 ppm with a maximum of 147.6 ppm. The average calculated methane mixing ratios for the TGS2600 and TGS2611 using the ML algorithm were 2.42 ppm and 2.40 ppm, with maximum values of 117.5 ppm and 106.3 ppm, respectively. A comparison of histograms generated using the analyzer and metal oxide sensors mixing ratios shows overlap coefficients of 0.95 and 0.94 for the TGS2600 and TGS2611, respectively. Overall, our results showed there was a good agreement between the ML-derived metal oxide sensors’ mixing ratios and those generated using the more accurate trace gas analyzer. This suggests that the response of lower-cost sensors calibrated using ML could be used to generate mixing ratios with precision and accuracy comparable to higher priced trace methane analyzers. This would improve confidence in low-cost sensors’ response, reduce the cost of sensor deployment, and allow for timely and accurate tracking of methane emissions.

Diagnosis of GHG Emissions in an Offshore Oil and Gas Production Facility

This work presents a diagnosis of greenhouse gas (GHG) emissions for floating production storage and offloading (FPSO) platforms for oil and gas production offshore, using calculation methodologies from the American Petroleum Institute (API) and U.S. Environmental Protection Agency (EPA). To carry out this analysis, design data of an FPSO platform is used for the GHG emissions estimation, considering operations under steady conditions and oil and gas processing system simulations in the Aspen HYSYS® software. The main direct emission sources of GHG are identified, including the main combustion processes (gas turbines for electric generation and gas turbine-driven CO2 compressors), flaring and venting, as well as fugitive emissions. The study assesses a high CO2 content in molar composition of the associated gas, an important factor that is considered in estimating fugitive emissions during the processes of primary separation and main gas compression. The resulting information indicates that, on average, 95% of total emissions are produced by combustion sources. In the latest production stages of the oil and gas field, it consumes 2 times more energy and emits 2.3 times CO2 in terms of produced hydrocarbons. This diagnosis provides a baseline and starting point for the implementation of energy efficiency measures and/or carbon capture and storage (CCS) technologies on the FPSO in order to reduce CO2 and CH4 emissions, as well as identify the major sources of emissions in the production process.

CH4 and CO2 Reductions from Methanol Production Using Municipal Solid Waste Gasification with Hydrogen Enhancement

This study evaluates the greenhouse gas (GHG) impacts of converting municipal solid waste (MSW) into methanol, focusing on both landfill methane (CH4) emission avoidance and the provision of cleaner liquid fuels with lower carbon intensity. We conduct a life cycle assessment (LCA) to assess potential GHG reductions from MSW gasification to methanol, enhanced with hydrogen produced via natural gas pyrolysis or water electrolysis. Hydrogen enhancement effectively doubles the methanol yield from a given amount of MSW. Special attention is given to hydrogen production through natural gas pyrolysis due to its potential for lower-cost hydrogen and reduced reliance on renewable electricity compared to electrolytic hydrogen. Our analysis uses a case study of methanol production from an oxygen-fired entrained flow gasifier fed with refuse-derived fuel (RDF) simulated in Aspen HYSYS. The LCA incorporates the significant impact of landfill methane avoidance, particularly when considering the 20-year global warming potential (GWP). Based on the LCA, the process has illustrative net GHG emissions of 183 and 709 kgCO2e/t MeOH using renewable electricity for electrolytic hydrogen and pyrolytic hydrogen, respectively, for the 100-year GWP. The net GHG emissions using 20-year GWP are −1222 and −434 kgCO2e/t MeOH, respectively. Additionally, we analyze the sensitivity of net GHG emissions to varying levels of fugitive methane emissions.

A systematic comparison of the energy and emissions intensity of hydrogen production pathways in the United Kingdom

Meeting climate targets requires profound transformations in the energy system. Most energy uses should be electrified, but where this is not feasible, hydrogen can be part of the solution. However, 98% of global hydrogen production involves greenhouse gas emissions, with an average of 12 kg CO2e/kg H2. Therefore, new hydrogen production pathways are needed in order to make hydrogen production compatible with climate targets. In this work, we fill this gap by systematically comparing the energy and emissions intensity of 173 hydrogen production pathways suitable for the UK. Scenarios include onshore and offshore pathways and the use of repurposed infrastructure. Unlike fossil-fuel based pathways, the results show that electrolytic hydrogen powered by fixed offshore wind could align with proposed emissions standards, either onshore or offshore. However, the embodied and fugitive emissions are important to consider for electrolytic pathways as they result in 10–50% of the total emissions intensity.

Identification of atmospheric emerging contaminants from industrial emissions: A case study of halogenated hydrocarbons emitted by the pharmaceutical industry

With the development of the pharmaceutical industry, halogenated hydrocarbons, which are the main raw materials and emissions of the pharmaceutical industry, may be defined as atmospheric emerging contaminants due to toxicity and low oxidation of the atmosphere. This study analyzed the volatile organic compounds (VOCs) emissions from four pharmaceutical companies located in the Yangtze River Delta. Samples were taken three times at each of the selected fixed and fugitive sampling sites in each company. Through testing, 141 VOCs were identified. The mean concentration and proportion of halogenated hydrocarbons from the four pharmaceutical companies were the highest of all the industries in the industrial park. They reached 18.9 ppm and 28.8 %, respectively. Fixed emissions of the companies exhibited the mean maximum concentration of dichloromethane and chlorobenzene, which are 11.4 ppm and 250.67 ppb. The mean concentration of fugitive emission of dichloromethane from the four companies in this study is lower than that of pharmaceutical companies in other studies. Newly detected halogenated hydrocarbons, such as 1,1-dichloropropanone and dichloronitromethane, present potential non-cancer and cancer risks to workers. Chlorobenzene was identified as a key potential cancer risk halogenated hydrocarbon the value of which reaches 0.00965. 2,6-dichloropyridine could be a potential emerging contaminant due to its lower MIR value and higher potential cancer risk. The study suggests that relevant pharmaceutical companies focus on the emissions of chlorobenzene and dichloromethane, which may be the atmospheric emerging contaminants for the pharmaceutical industry and focus on improve the treatment of waste gases in workshops and sewage stations.

Coal Ash Triggers an Elevated Temperature Landfill Development: Lessons from the Bristol Virginia Solid Waste Landfill Neighboring Community

Landfills for disposing of solid waste are designed, located, managed, and monitored facilities expected to comply with government regulations to prevent contamination of the surrounding environment. After the average life expectancy of a typical landfill (30 to 50 years), a large investment in the construction, operation, final closure, and 30-year monitoring of a new site is needed. In this case study, we provide a holistic explanation of the unexpected development of elevated temperature landfills (ETLFs), such as that in the city of Bristol (United States) on the border of the states of Virginia and Tennessee, including the initial role played by coal ash. Despite the increasing frequency of ETLF occurrence, there is limited knowledge available about their associated environmental problems. The study uses mixed (qualitative, quantitative, and mapping) methods to analyze (1) the levels of odoriferous reduced sulfur compounds, ammonia, and volatile organic compounds (VOCs) emitted, (2) the ratio of methane to carbon dioxide concentrations in five locations, which dropped from unity (normal landfill) to 0.565, (3) the location of gas well heads with gradients of elevated temperatures, and (4) the correlation of the filling rate (upward of ~12 m y−1) with depth for registered events depositing coal ash waste. The work identifies spatial patterns that support the conclusion that coal ash served as the initiator for an ETLF creation. The case of the city of Bristol constitutes an example of ETLFs with elevated temperatures above the regulatory United States Environmental Protection Agency (EPA) upper threshold (65 °C), having alongside low methane emissions, large production of leachate, land subsidence, and a large production of organic compounds. Such landfills suffer abnormal chemical reactions within the waste mass that reduce the life expectancy of the site. Residents in such communities suffer intolerable odors from fugitive emissions and poor air quality becomes prominent, affecting the well-being and economy of surrounding populations. Conclusive information available indicates that the Bristol landfill has been producing large amounts of leachate and hazardous gases under the high pressures and temperatures developed within the landfill. A lesson learned, which should be used to prevent this problem in the future, is that the early addition of coal ash into the landfill would have catalyzed the process of ETLF creation. The work considers the public health risks and socioeconomic problems of residents exposed to emissions from an ETLF and discusses the efforts needed to prevent further incidents in other locations.

Evaluation of greenhouse gas emission and reduction potential of high-food-waste-content municipal solid waste landfills: A case study of a landfill in the east of China

This study proposes a comprehensive evaluation method based on a two-stage model to assess greenhouse gas (GHG) emissions and reductions in high-food-waste-content (HFWC) municipal solid waste (MSW) landfills. The proposed method considers typical processes such as fugitive landfill gas (LFG), LFG collection, flaring, power generation, and leachate treatment. A case study of an HFWC MSW landfill in eastern China is considered to illustrate the evaluation. The findings revealed that the GHG emissions equivalent of the case landfill amounted to 21.23 million tons from 2007 to 2022, averaging 1.03 tons CO2-eq per ton of MSW. There was a potential underestimation of LFG generation at the landfill site during the initial stages, which led to delayed LFG collection and substantial fugitive LFG emissions. Additionally, the time distribution of GHG emissions from HFWC MSW was significantly different from that of low-food-waste-content (LFWC) MSW landfills, with peak emissions occurring much earlier. Owing to the rapid degradation characteristics of HFWC MSW, the cumulative LFG production of the landfill by 2022 (2 years after the final cover) was projected to reach 77 % of the total LFG potential. In contrast, it would take until 2030 for LFWC MSW landfills to reach this level. Furthermore, various scenarios were analyzed, in which if the rapid LFG generation characteristics of HFWC MSW are known in advance, and relevant facilities are constructed ahead of time, the collection efficiency can be improved from 31 % to over 78 %, resulting in less GHG emissions.

Technological and policy directions for scaling-up blue hydrogen in India

The Government of India has indicated that hydrogen as an energy carrier will be a key part of its decarbonization solutions. Greater policy focus has been noticed on green hydrogen produced from electrolysis using renewable-powered electricity. That said, some other missions, such as the National Coal Gasification Mission, could directly tie into blue hydrogen production (from fossil fuels with CO2 storage). In this paper, we suggest two major policy initiatives for effective deployment of blue hydrogen. These include a comprehensive measurement programme for fugitive emissions and a level-playing field to ensure parity among sources. Moreover, we also provide insights as to why coalbed methane and underground coal gasification could provide somewhat overlooked feedstock of blue hydrogen. In doing so, the paper outlines the current state-of-the-art on blue hydrogen production in India, and recommendations for its scale-up.

Estimating Total Methane Emissions from the Denver-Julesburg Basin Using Bottom-Up Approaches

Methane is a powerful greenhouse gas with a 25 times higher 100-year warming potential than carbon dioxide and is a target for mitigation to achieve climate goals. To control and curb methane emissions, estimates are required from the sources and sectors which are typically generated using bottom-up methods. However, recent studies have shown that national and international bottom-up approaches can significantly underestimate emissions. In this study, we present three bottom-up approaches used to estimate methane emissions from all emission sectors in the Denver-Julesburg basin, CO, USA. Our data show emissions generated from all three methods are lower than historic measurements. A Tier 1/2 approach using IPCC emission factors estimated 2022 methane emissions of 358 Gg (0.8% of produced methane lost by the energy sector), while a Tier 3 EPA-based approach estimated emissions of 269 Gg (0.2%). Using emission factors informed by contemporary and region-specific measurement studies, emissions of 212 Gg (0.2%) were calculated. The largest difference in emissions estimates were a result of using the Mechanistic Air Emissions Simulator (MAES) for the production and transport of oil and gas in the DJ basin. The MAES accounts for changes to regulatory practice in the DJ basin, which include comprehensive requirements for compressors, pneumatics, equipment leaks, and fugitive emissions, which were implemented to reduce emissions starting in 2014. The measurement revealed that normalized gas loss is predicted to have been reduced by a factor of 20 when compared to 10-year-old normalization loss measurements and a factor of 10 less than a nearby oil and production area (Delaware basin, TX); however, we suggest that more measurements should be made to ensure that the long-tail emission distribution has been captured by the modeling. This study suggests that regulations implemented by the Colorado Department of Public Health and Environment could have reduced emissions by a factor of 20, but contemporary regional measurements should be made to ensure these bottom-up calculations are realistic.

A holistic approach for assessing occupational health risk due to fugitive emissions in petrochemical processes: Inherent health hazard level index (IHHLI)

AbstractFugitive emissions from petrochemical facilities have become a major concern due to their impact on plant productivity, the environment, and health. In regard to health, petrochemical workers are at higher occupational health (OH) risk due to their continuous exposure to these harmful emissions. Inherent OH and safety indexes are the most common methods used for assessing OH risk due to fugitive emissions. These methods usually focus on the sources of health hazards, such as chemical substances, process conditions, and process equipment. Therefore, these methods are considered good for measuring the severity of the OH risk. However, based on the source, pathway, receptor (SPR) model, the OH risk due to fugitive emissions is also dependent on the pathway and receptor, where leak and exposure hazards may take place, respectively. For a holistic OH risk assessment, these hazards need to be considered. This was achieved by developing an OH risk assessment methodology that provides an effective assessment that takes into consideration hazards at the source, pathway, and receptor. This paper focuses on the source part of the SPR model, while the pathway and receptor parts will be covered in future publications. This paper presents an index‐based method named the inherent health hazard level index (IHHLI) developed for evaluating the severity of the fugitive emission‐induced OH risk. The IHHLI is developed by an expert‐based selection of the most common and relevant health hazard indicators published in the literature. Based on industry testing, the IHHLI can provide a reliable OH hazard evaluation.

Reducing Helium Consumption in Valve Manufacturing: Alternative Test Fluid for Fugitive Emissions Production Testing

Abstract Helium gas is used for fugitive emissions testing of industrial components such as valves. Purpose of these tests is to prevent unintentional and undesirable releases of process gas, from industrial sites, into the environment. These fugitive emissions are direct negative contributors to greenhouse gas emissions and local air quality, and therefore linked to environmental and health and safety rules. The valve industry has standards in place to qualify valves for fugitive emissions performance. For instance, ISO 15848-1 (2015, “Industrial Valves – Measurement, Test and Qualification Procedures for Fugitive Emissions Part 1: Classification System and Qualification Procedures for Type Testing of Valves”) classifies valve designs based on emissions, temperature, endurance, and describe the methods for prototype testing. ISO 15848-2 (2015, “Industrial Valves – Measurement, Test and Qualification Procedures for Fugitive Emissions Part 2: Production Acceptance of Test Valves”) defines the criteria for production testing. Test methods in these standards are currently based on Helium gas or Methane gas as the test fluid. With the perspective that governments and the energy industry are setting distinct and increasingly challenging goals to reduce emissions and decarbonize, it is expected that the volume of tests performed will increase in the near future, which, based on a finite resource of helium, may not be sustainable in the future.

Generation and emission mechanism of polycyclic aromatic hydrocarbon (PAHs) during the coking process in Shanxi, China

Although coking process is the important source of polycyclic aromatic hydrocarbons (PAHs) in the environment, the generation and emission of PAHs during this process is unclear. It is crucial to clarify the formation mechanism of PAHs in coal pyrolysis during the coking process for effectively identifying and controlling the emission of these organic pollutants. In this study, the combination of laboratory simulation and field sampling was used to analyze the mechanism of PAHs formation and emission in coking process. The release of PAHs from the pyrolysis process of coal blends used in coking plants was 1778.20 ± 111.95 μg · g−1, which was much higher than the content of free PAHs in raw coal (76.50 ± 12.46 μg · g−1). 3-ring PAHs were the most abundant components of free PAHs and pyrolysis-generated PAHs. PAH formation during pyrolysis of coal blends was primarily attributed to the cracking of the macromolecular structure of coal, with minimal influence of free PAHs in blended coal. The emission of PAHs from coal-charging was higher (62.93 ± 17.75 μg · m−3) than that from pushing of coke (11.79 ± 1.91 μg · m−3·, PC) and combustion of coke oven gas (5.53 ± 1.20 μg · m−3, CG), and was mainly related to free PAHs in coal. In contrast, the characteristics of PAHs in the flue gas of PC and CG were similar to those from blended coal pyrolysis. PAHs in fugitive emission from coke oven were primarily affected by flue gas leakage and were mainly related to coal pyrolysis and free PAHs in blended coal.

Low-carbon development path based on carbon emission accounting and carbon emission performance evaluation: a case study of Chinese coal production enterprises.

Carbon emission accounting is the basic premise of effective carbon emission reduction and management. This study aimed to establish the carbon emission model and performance evaluation framework of coal mine production enterprises and clarify the low-carbon development path of enterprises. In this study, we took a typical coal production enterprise (K enterprise) in the Shanxi province of China as the research object. We also estimated the carbon emissions of the enterprise mainly according to the Chinese Carbon Emission Accounting Standard (GB/T 32151.11-2018). The triangular model was used to construct the carbon performance evaluation framework. On this basis, we suggested the enterprise's low-carbon development path. The results showed that (1) the carbon emission of K enterprise in 2021 was 36,875.38 tCO2eq; the carbon emission intensity of each ton of coal produced was 0.089 tCO2eq. The critical carbon emissions were electricity consumption and methane fugitive emissions during production. (2) The evaluation indicators for carbon emission performance revealed an imbalance in K enterprise's economic, energy, and environmental development in 2021. The work on energy saving and consumption reduction was relatively weak. (3) Countermeasures for low-carbon development, including a carbon emission ledger, were proposed based on carbon emission accounting and performance evaluation results. This study can help typical underground coal production enterprises in Shanxi province obtain more accurate carbon emission data, providing practical guidance and reference for the same underground coal production enterprises to improve the carbon emission control effect.