Gas Composition Analysis Research Articles

Revising curricular on medical ethics: a way forward

This study aimed to derive an index quantifying the state of alteration of cadavers by quantifying the presence of gas in the body using postmortem multidetector computed tomography (MDCT) imaging, and to validate the index by defining its sensitivity and specificity. The RA (radiological alteration)-index was derived from postmortem MDCT data from 118 nontraumatically deceased people. To validate the index, 100 additional scanned bodies (50% traumatically deceased) were retrospectively examined by two independent observers. Presence of gas at 82 sites was assessed by a radiologist, whereas a forensic pathologist only investigated the seven sites used for the RA-index. The RA-index was highly correlated to the overall presence of gas in all 82 sites (R2 = 0.98 in the derivation set and 0.85 in the validation set). Semiquantitative evaluation of gas presence in each site showed moderate reliability (Cohen's kappa range, 0.41–0.78); nevertheless, the overall RA-index was very reliable (ICC2,1 = 0.95; 95% CI 0.92–0.96). Examiner using the RA-index detected heart cavities full of gas with a sensitivity of 100% (95% CI 51.7–100) and a specificity of 98.8% (92.6– 99.9). We conclude that determining the presence of gas at seven sites is a valid means to measure the distribution of gas due to cadaveric alteration in the entire body. The RA-index is rapid, easy-to-use, and reliable for nonexperienced users, and it is a valid method to suspect the normal presence of gas from cadaveric alteration. MDCT can be used to screen for gas embolism and to give indications for gas composition analysis (gas chromatography).

Design of a Method for Test Diagnostics of an Internal Combustion Engine Based on the Analysis of the Exhaust Gas Composition

The introduction of methods for timely diagnostics of internal combustion engines allows maintaining the environmental indicators of the car fleet at the highest level. (Research purpose) The research purpose is in increasing the reliability of diagnostics of internal combustion engines by using data obtained by selective sampling of exhaust gases. (Materials and methods) Informational, mathematical and experimental research methods, including methods for statistical processing of results and analysis of data obtained during experiments were used during the study. (Results and discussion) The main systems that affect the environmental performance of internal combustion engines has been identified: the fuel supply system, the ignition system and the exhaust gas neutralization system. The article describes a generalized mathematical model for calculating the characteristics of exhaust gases. Authors conducted operational tests on 35 internal combustion engines with justification of their number according to standard methods. The actual value of diagnostic parameters was processed into relative percentages for drawing a nomogram. A zero value has been set for the reference state of the elements specified by the manufacturer. (Conclusions) It was found that the dominant number of failures accounted for internal combustion engines, in detail: the ignition system produces 15-25 percent of failures, the power system produces 30-44 percent, the exhaust system produces 10-15 percent. It was found that for unambiguous identification of any combination of factors, it is necessary to have output values of at least three evaluation criteria. It was found that the most sensitive parameters for evaluating the technical condition of the three systems are: changes in the engine crankshaft speed, the parameters of exhaust gas toxicity, CO, CO2, CH, O2 when providing test modes (operation of the internal combustion engine on 1 cylinder at 20 and 40 percent of the throttle opening). The article describes designed a gasoline engine loader for the implementation of diagnostic modes and control of diagnostic parameters, that allows to create operating loads with an accuracy of 0.1 percent.

Analysis of Gas Composition and Nitrogen Sources of Shale Gas Reservoir under Strong Tectonic Events: Evidence from the Complex Tectonic Area in the Yangtze Plate

Strong tectonic movement brings great risk to exploration of shale gas in southern China, especially in Lower Cambrian shale with complex tectonic backgrounds, which has good hydrocarbon-generation matter but low or no gas content. In this paper, the Lower Cambrian shale from the southeast Chongqing region, located in the Upper Yangtze Platform, and the Xiuwu Basin, located in the Lower Yangtze Platform, were selected as the research objects. First, the gas components in shale gas samples were measured, then analysis of nitrogen isotopic was used to reveal the nitrogen sources. Using regional geological backgrounds, core description, and seismic interpretation, combined with the perpendicular and parallel permeability test and focused ion beam–helium ion microscopy (FIB–HIM) observation, the reasons for high content of nitrogen in the Lower Cambrian shale from the Xiuwu Basin and the Southeast Chongqing region were clarified. The results indicate that the main sources of nitrogen in the Lower Cambrian shale gas at the Southeast Chongqing region is the thermal evolution of organic matter and atmosphere. Nitrogen in the atmosphere is filled into the shale reservoir through migration channels formed by detachment layers at the bottom of the Lower Cambrian, shale stratification planes, and widespread thrust faults. Nitrogen was also produced during the thermal evolution of organic matter. Both are responsible for the low content of hydrocarbon and high content of nitrogen of shale gas in the Southeast Chongqing region. Further, the main sources of nitrogen in the Lower Cambrian shale gas at the Xiuwu Basin is the upper mantle, superdeep crust, and atmosphere. Nitrogen in the atmosphere is also filled into the shale reservoir through migration channels formed by detachment layers at the bottom of the Lower Cambrian, shale stratification planes, and widespread thrust faults. Nitrogen was also produced by volcanism during the Jurassic. Both are the causes of the low content of hydrocarbon and high content of nitrogen in shale gas in the Xiuwu Basin. Finally, destruction models for shale gas reservoirs with complex tectonic backgrounds were summarized. This research aimed to provide a theoretical guidance for shale gas exploration and development in areas with complex tectonic backgrounds.

Design of a Compact Time-of-Flight Mass Spectrometer for Space Application.

A miniature reflectron time-of-flight mass spectrometer (TOF MS) with orthogonal extraction coupled with electron impact (EI) ionization source can be used to perform in situ gas composition analysis in a planetary environment. However, performances such as the mass resolution, sensitivity, limit of detection, mass range, and mass accuracy are often decreased because of miniaturization. Herein, a compact instrument for space applications has been developed, and its performance has been evaluated. The mass of the TOF MS is 13.4 kg, with dimensions of 300 mm × 200 mm × 200 mm, and the power consumption is 25 W. In this paper, the design of the ion source, mass analyzer, and detector is discussed in detail. The upper limit of the mass range is greater than 500 amu, and the best resolving power obtained so far on the miniature TOF MS is around 405 at full width half maximum (FWHM); other performance indexes of the instrument are also determined, where the worst case for mass stability is 0.49%, together with a mass accuracy of 0.12% and a sensitivity of 0.6 mV/ppm.

Analysis of Lower Cambrian shale gas composition, source and accumulation pattern in different tectonic backgrounds: A case study of Weiyuan Block in the Upper Yangtze region and Xiuwu Basin in the Lower Yangtze region

Marine shale gas exploration in southern China has successes and failures. Under the condition of great hydrocarbon generation material basis, shale gas wells drilled from some shale gas blocks are rich in methane, while the wells in other shale gas blocks with high nitrogen and low hydrocarbon gas, which indicates that they have different accumulation mechanisms. Therefore, the study of gas composition in shale will help us to figure out the mechanism of shale gas accumulation and loss. In this paper, the Lower Cambrian shale from Wei-201 well in Upper Yangtze Weiyuan Block and Jiangye-1 well from Lower Yangtze Xiuwu Basin are selected as research object, and shale samples are used for tests and experiments including analysis of gas composition and nitrogen isotope, test of porosity and TOC content, overburden permeability test, permeability test before and after methane adsorption under different osmotic pressure, permeability test parallel and vertical to the bedding surface, FIB-SEM (Focus Ion Beam Scanning Electron Microscope) and FIB-HIM (Focused Ion Beam Helium Ion Microscope). Finally, the reasons for the difference in the gas components of the Lower Cambrian shale gas in Weiyuan Block and Xiuwu Basin are studied by means of seismic interpretation, core description and outcrop observation besides the tests and experiments. The results show that the gas components of the Lower Cambrian shale in Weiyuan Block, the Upper Yangtze, mainly consist of methane, derived from liquid hydrocarbon cracking. The sealing capacity of roof and floor, the great self-sealing of shale and the flat anticline structure contribute to the high methane content in shale gas. The Lower Cambrian shale gas in Xiuwu Basin, the Lower Yangtze, is mostly nitrogen, which is derived both from atmosphere and deep crust-upper mantle. The detachment layer at the bottom of the Lower Cambrian, the widely developed deep faults and the Jurassic volcanic activity are the reasons for the high nitrogen and low hydrocarbon of shale gas. Based on the above analysis, the patterns are summarized for shale gas accumulation in the simple anticline background and reservoir destruction in the complex syncline background.

CO2 gasification of char from spent mushroom substrate in TG-MS system

Gasification of the char obtained from the spent substrate after mushroom cultivation was carried out in a thermobalance connected to a mass spectrometer in the temperature range from 200 to 950 °C and CO2 concentration from 5 to 100 vol%. Under non-isothermal conditions, in addition to the char gasification process, both carbonation and calcination reactions occurred. The investigation of gasification kinetics in CO2 was carried out under isothermal conditions. The rate of gasification reaction was determined from the shrinking core model, and kinetic constant has been calculated from Langmuir–Hinshelwood kinetics. On the basis of the conducted research, it was observed that the saturation of active sites on the char particles occurred above 50 vol% CO2, regardless of temperature. The analysis of gas composition indicates CO as the main product of gasification.

Calculation of combustion air required for burning solid fuels (coal / biomass / solid waste) and analysis of flue gas composition

In power plants or any combustion systems, for a maximum efficiency of combustion, an operational safety procedure (reduction of CO emissions) and environmental pollution reduction, it is highly important to determine and monitor the flue gas composition resulting from burning of solid fuels in combustion chambers. The paper presents the development of a web application, which can prove extremely useful for thermo-energetic engineers and researchers who wish to perform combustion calculations of the solid fuels (coal / biomass / solid waste materials). The application allows users to enter the data on the elemental composition of the analyzed fuel, excess air and fuel flow rate to determine volume of oxygen and air necessary for fuel combustion and flue gas volume. This web application can be also successfully used both in designing stage of the combustion equipment and in the operating stage since the chemical composition of solid fuels is extremely variable (particularly in the case of waste materials) consequently it is highly important to know the optimum quantity of air required for a maximum efficiency of combustion. Proper control of the combustion process will lead both to the optimum functioning of the equipment and to less polluting combustion gasses and will also reduce thermal losses.

Study of synthesis gas composition, exergy assessment, and multi-criteria decision-making analysis of fluidized bed gasifier

A system based a fluidized bed gasifier with steam as a gasifying agent is investigated in details. Comparing the synthesis of gas compositions with experimental data available in the literature is used to validate the model. The synthesis of gas composition and efficiencies of the system is investigated respect to different biomasses considered as gasification fuels. The results indicate that the molar fractions of hydrogen and carbon dioxide are increased and the molar fraction of carbon monoxide is reduced with steam to biomass ratio (STBR). The hydrogen and cold gas efficiencies are improved with decreasing STBR. Hydrogen, cold gas, and exergy efficiencies are enhanced with temperature. The results illuminate that pine sawdust and straw have the highest hydrogen production and legume straw produces the lowest CO molar fraction. Straw has the highest hydrogen efficiency, eucalyptus and straw have the highest cold gas efficiency, and eucalyptus has the highest exergy efficiency. A systematical analytical hierarchy process (AHP)/technique for order preferences by similarity to ideal solution (TOPSIS) couple method are utilized to select the best alternative. The results illuminate that eucalyptus, straw, and pine sawdust are the best candidates, respectively as gasification fuel based on the considered criteria.

Influence of igneous intrusions on the thermal maturity of organic matter in the Sverdrup Basin, Arctic Canada

The influence of igneous intrusions on the trend of thermal maturity with depth in two drillholes, one on Ellesmere Island and the other on Ellef Ringnes Island, Arctic Canada, was assessed using vitrinite and solid bitumen reflectance, Rock-Eval pyrolysis/TOC, and gas composition analysis in order to assess the impact of igneous intrusions on the hydrocarbon system in the area. Thick sequences of Permo-Pennsylvanian strata in Sabine Peninsula, Melville Island, were intruded by two igneous intrusions in the Panarctic Chads Creek B-64 (influenced by one intrusion) and the Panarctic Drake Point D-68 (influenced by two intrusions). Sedimentary strata in Chads Creek B-64 were intruded by a 120 m-thick diabase sill (with temperature of ~1100 °C) of unknown age. This resulted in increased reflectance of vitrinite from 0.90% to 1.65% and of pyrobitumen from 2.90% to almost 5.80% near the sill contact at depth of 3600 m. Solid bitumen outside of the thermal aureole zones and having reflectance values <1.50% followed the extrapolated trend for solid bitumen present in the country rocks. In Panarctic Drake Point D-68, the intrusives are granodiorite sills of 45 m and 75 m thickness and were emplaced during the Upper Jurassic (152 Ma) and Lower Cretaceous (131 Ma). The intrusion temperature was 800 °C. The Vitrinite Rr prior to sill emplacement was <1.0% outside the aureole and increased to approximately 2.0% near the intrusive zone. The rocks were well-lithified prior to sill emplacement. Solid bitumen underwent carbonization after being exposed to a temperature of at least 800 °C. Solid bitumen reflectance also showed a sudden increase from a minimum of 1.50% outside the aureole to approximately 7.0% near the sill contact, a 5× increase as compared to an increase of 2× for vitrinite. This indicates that solid bitumen is a very sensitive indicator of temperature variation, more sensitive than vitrinite. Solid bitumen reflectance prior to the sill emplacement can only be inferred from the solid bitumen below the lower, younger sill because of poor control on solid bitumen in the interval just above the upper, older sill. Reflectance trends above and below the sills appear to be symmetrical despite the superimposition of the effects of one sill on the other. The metamorphic effects of the sill, as determined vertically by the reflectance trend, can be observed for a distance of up to seven times its thickness. The upper, older sill is approximately 45 m thick and the thermal aureole zone above it has a width of 330 m. The thickness of the aureole below the sill is difficult to establish because it has been obliterated by the effect of the lower, younger sill. The thickness of the lower sill is 75 m. An additional factor that influenced solid bitumen reflectance in this case may have been the thickness of the sill, which, in turn, affects the cooling time of the intrusive body. The granodiorite sills are approximately 45–75 m thick and the diabase sill is almost 120 m.

Characterization of the products obtained by pyrolysis of oil sludge with steel slag in a continuous pyrolysis-magnetic separation reactor

In this study, a strategy of combining oil sludge with steel slag to improve the quality of tar resulting from oil sludge pyrolysis and steel slag recycling is proposed. Oil sludge pyrolysis with the addition of different amounts of steel slag at different temperatures was conducted by employing a continuous pyrolysis-magnetic separation (CPM) process. The characteristics of oil pyrolysis were characterized by thermogravimetric analysis (TG), the compositions of the non-condensable gas and tar were characterized by gas chromatography (GC) and gas chromatography-mass spectrometry (GC–MS). The effect of steel slag on the tar composition and char surface morphology was analysed. The recovered steel slag concentrate was measured by a magnetic separation method. The results indicated that steel slag addition caused the weight loss rate of oil sludge to increase. The yield of tar reached a maximum of 10.63% at 550 °C, and the increase in temperature intensified the secondary thermal cracking of the volatile fraction and decreased the tar yield. The gas composition analysis indicated that steel slag could act as a catalyst in improving the H2 content during the pyrolysis process of oil sludge. The addition of steel slag significantly increased the content of short alkanes and increased the C5 ∼ C10 fraction by improving the decomposition of the C15 ∼ C20 fraction. The recovery of steel slag from the solid pyrolysis products of oil sludge containing steel slag was conducted in a magnetic separator, and the maximum recovery rate could reach 55.03%. It was concluded that the integration of oil sludge pyrolysis with steel slag and the recovery of steel slag from the solid pyrolysis products of oil sludge containing steel slag could be feasible.

A sustainable bioenergy conversion strategy for textile waste with self-catalysts using mini-pyrolysis plant

Based on the current economic and environmental analysis of the textile waste streams, textile waste alone can be a promising source of renewable energy. To realize that, catalyst-supported pyrolysis was used in the present research to treat textile waste and convert it into value-added energy carriers while attempting to minimize consumption of consumable chemicals (catalysts) and pyrolysis time and maximize the yield of valuable bio-oil and gases (Methane and Hydrogen). Pyrolysis was conducted on waste jeans (a major fraction of textile waste, rich in cellulose/cotton) with different dye colors (black and blue) and dye-originating heavy metals (used as a self-catalysts). Waste jeans of both colors were pyrolyzed in original condition and after acid leaching to remove the heavy metals for comparison. Also, the pyrolysis experiments were performed according to Technology Readiness Levels (TRL) concept, particularly in laboratory and pilot scale phases. At the first phase, Differential thermal analysis/Thermogravimetric analysis/3D-Fourier-Transform Infrared spectroscopy was employed to simulate the pyrolysis on a lab scale (fundamental level of TRL) and study the thermal and chemical decomposition of the selected samples up to 800 °C. At the second stage, a pilot pyrolysis plant was built (based on the fundamental results received from lab scale) to simulate the industrial energy conversion conditions and obtain the data needed to apply the developed approach at industrial scale. The developed plant consisted of four units: pyrolysis reactor (capacity 300 g, Nitrogen ambient, and max. temp. 800 °C), gas purification unit, instantaneous gas composition analysis unit (to study the effect of pyrolysis temperature on the generated Oxygen, Nitrogen, Carbon Monoxide, Carbon dioxide, Methane, and Hydrogen gases), and gas products collection unit. The pyrolysis products were analyzed using Gas Chromatography–Mass Spectrometry, Fourier-Transform Infrared Spectroscopy, elemental analysis, and Scanning Electron Microscope- Energy-dispersive X-ray Spectroscopy. The results showed that the developed technology successfully converted more than 82% of the feedstock into liquid-gas products and that the untreated feedstock had effective bio-oil yield 36–37.6% (depending on the composition of self-catalysts), which was ∼20% higher compared to the treated batches; 18% reduction in pyrolysis time of untreated feedstock was achieved as well.

In vitro validation of indirect calorimetry device developed for the ICALIC project against mass spectrometry

Accurate evaluation of the energy needs is required to optimize nutrition support of critically ill patients. Recent evaluations of indirect calorimeters revealed significant differences among the devices available on the market. A new indirect calorimeter (Q-NRG®, Cosmed, Roma, Italy) has been developed by a group of investigators supporting the international calorimetry study initiative (ICALIC) to achieve ultimate accuracy for measuring energy expenditure while being easy to use, and affordable. This study aims to validate the precision and the accuracy of the Q-NRG® in the in-vitro setting, within the clinically relevant range for adults on mechanical ventilation in the ICU. Mass spectrometry is the reference method for the gas composition analysis to evaluate the analytic performances of the Q-NRG®. The accuracy and precision of the O2 and CO2 measurements by the Q-NRG were evaluated by comparing the measurements of known O2 and CO2 gas mixtures with the measurements by the mass spectrometer (Extrel, USA). The accuracy and precision of the Q-NRG® for measurements of VO2 (oxygen consumption) and VCO2 (CO2 production) at clinically relevant ranges (150, 250 and 400ml/min STPD) were evaluated by measuring simulated gas exchange under mechanically ventilated setting at different FiO2 settings (21-80%), in comparison to the reference measurements by the mass spectrometer-based mixing chamber system. The measurements of gas mixtures of predefined O2 and CO2 concentrations by the Q-NRG® were within 2% accuracy versus the mass spectrometer measurements in Passing Bablok regression analysis. In a mechanically ventilated setting of FiO2 from 21 up to 70%, the Q-NRG® measurements of simulated VO2 and VCO2 were within 5% difference of the reference mass spectrometer measurements. Invitro evaluation confirms that the accuracy of the Q-NRG® indirect calorimeter is within 5% at oxygen enrichment to 70%; i.e. maximum expected for clinical use. Further recommendations for the clinical use of the Q-NRG® by will be released once the ongoing multi-center study is completed.

Analysis of gas composition in oil-filled faulty equipment with acetylene as the key gas

The article presents results of oil-dissolved gas analysis for 239 units of high-voltage equipment with faults under which acetylene is the key gas. The analysis revealed 13 types of fault with acetylene as the key gas that are differentiated by values of the dissolved gas ratios, their concentrations, and fault nomographs. For each type of fault, graphic domains are plotted that, unlike the nomographs, allow taking into account a possible coordinate drift. A graphic domain based fault identification technique is introduced. The types of fault are briefly described, examples of their identification by different investigators given. Duval Triangle based comparative analysis of the equipment diagnosis data is performed. It is revealed that diagnoses made by different methods may differ significantly both from each other and from actual diagnoses. The results presented allow increasing fault identification accuracy via dissolved gas analysis data.

단입자 바이오매스 펠릿의 연소특성에 관한 연구

As a pretreatment for energy conversion, biomass is often pelletized for efficient transport, storage, and handling with an increased bulk density and size uniformity. In this study, the combustion behaviors of a single biomass pellet were investigated for pine wood and bean husk in comparison to sub-bituminous coal. The pellets were immediately exposed to an updraft flow of nitrogen and air for pyrolysis and combustion analysis. The hot gas flow were at approximately 1080 K and the pellets were burned in a range of 21-40% oxygen for the combustion behaviors. The sequential progress of combustion was monitored by video recording, optical pyrometry, and gas composition analysis for their ignition, flame characteristics, and burnout time. According to the results, the biomass pellets had fast ignition, which was attributed to the release of oxidizing gases at an early stage. TGA and pyrolysis analysis also indicated that biomass had the fast volatile release due to their primary components. The flame size of pine wood were the largest among three pellets while the coal had the highest flame temperature with the smallest flame size.

The Impact of Fuel Type on the Output Parameters of a New Biofuel Burner

Intensified action aimed at reducing CO2 emissions and striving for energy self-sufficiency of both business entities and individual consumers are forcing the sustainable development of environmentally friendly and renewable energy sources. The development of an appropriate class of equipment and production technology is not without significance in this process. On the basis of a proven design for a combustion burner for ecological fuels, a new biofuel burner, also dedicated to prosumers’ energetics, was built. The aim of the study was to determine the effect of the type of biofuel on a burner’s output parameters, especially gaseous emissions, during the combustion of four types of fuels, including three types of biomass. The combustion temperature was measured for lignite, wood pellets, straw pellets, and sunflower pellets. An analysis of exhaust gas composition was performed for lignite and wood pellets. The results of exhaust emissions and combustion temperatures were compared with the burners currently in use. The use of a new burner might contribute to cleaner combustion and reducing the emissions of some gaseous components.

Complex gas hydrate system in a gas chimney, South China Sea

Abstract Gas hydrates and deep-sea cold seeps are of interest to industry and academia for several reasons, including their implications for offshore geohazards and unconventional resources, and for global climate change and carbon cycling. Guangzhou Marine Geological Survey (GMGS) implemented its fifth gas hydrate drilling expedition in the QiongDongNan Sea Area (QDN-SA) of the northern South China Sea (SCS) from June to September 2018. Multidisciplinary investigations, including Logging While Drilling (LWD), pressure and non-pressure coring, gas composition analyses, in situ temperature and permeability measurements, pore water geochemical analyses, and a regional seismic survey, reveal a complex distribution of gas hydrate within a vertical chimney structure. LWD profiles record high resistivity anomalies and high P-wave velocity variations at 9–174 mbsf, suggesting the coexistence of free gas and gas hydrate in the sediment column throughout the investigated gas chimney. Hydrate-bound and void gas is an admixture of methane (70.1%–98.3%) and heavier hydrocarbons (C2H6: 0.16%–17.59%, C3H8: 0.05%–9.88%, i-C4H10:

Rich biomass combustion: Gaseous and particle number emissions

The cone calorimeter is a standard test method for material behaviour in fires. The principle of the cone calorimeter is to use an electric radiant heater to raise the temperature of the combustion zone and ignite the fuel. 35 kW/m2 was used in the present work, as this has been previously shown to be sufficient to establish fully developed combustion of biomass materials such as wood. As one of the main fire loads is wood and wood is the dominant biomass for energy generation, it is reasonable to use the cone calorimeter to characterize the combustion of biomass on a small scale and pine was used in the present work. The cone calorimeter was used in the controlled atmosphere mode with an enclosure around the test biomass that enabled the air flow for biomass combustion to be controlled at 19.2 g/m2s, which corresponds to a combustion heat release rate HRR of 57 kW/m2, assuming all the oxygen in the air is consumed. This air flow will be shown to generate rich combustion at a metered equivalence ratio, Ø, of about 2, which is comparable with the first gasification stage of biomass two stage burning in log burners and pellet burners, where air is added downstream of the gasification stage of biomass combustion. Soot emissions are generated in this rich gasification stage burning and potentially oxidized in the oxidation second stage burning. The rich burning gasification zone particulate emissions were analysed for number size distribution using the Cambustion DMS 500 particle size analyser. The exit from the controlled combustion zone was extended in a 75 mm diameter chimney where a mean gas sample was taken. A heated Gasmet FTIR was used for gas composition analysis, using a heated sample line, filter and pump from the sample point to the analyser. The particles emitted were sampled after the second stage combustion from entrained air into the chimney discharge gases into a dilution tunnel with a fixed gas flow rate of 24 l/s, which gave a dilution ratio of the primary combustion gases of 150/1 which is required for nano-particle size analysis. A Cambustion DMS500 electrical mobility particle number and size instrument was used with size resolution from 5 to 1000 nm. The present results show that in the rich burning first stage chimney sample there were very high levels of 20 nm nanoparticles, 1 × 1010/cc, and an accumulation mode peak at 200 nm. The presence of the 20 nm particles makes the particulate emissions extremely toxic.

Geochemical characteristics of tight sandstone gas and hydrocarbon charging history of Linxing area in Ordos Basin, China

Abstract Genetic type, source, charging history and reasons for secondary biogenic transformation of tight sandstone gas in the Linxing area in China's Ordos Basin have been studied through a combined analysis of gas compositions, isotopes of alkane and carbon dioxide, fluid inclusions and basin simulation. Tight sandstone gas in this area is predominated by methane, and the dryness coefficient is between 0.864 and 0.997 (average = 0.969). The δ13C1 values of methane and ethane in this area range from −44.5‰ to −33.2‰ (average = −39.4‰) and from −27.5‰ to −24.4‰ (average = −25.9‰), respectively. The non-hydrocarbon gases are nitrogen, followed by carbon dioxide and argon, and δ13C of carbon dioxide ranges from −14.6‰ to 8.6‰. The homogenization temperatures of gas and gas-liquid inclusions in P2s and C3t in Linxing range from 80 °C to 170 °C, which are concentrated at 120–130 °C. The identification of gas origin indicates that tight sandstone gas is coal-type gas, which is mainly due to thermal evolution, followed by the mixing of secondary biogenic gas. Geological conditions and gas geochemical characteristics suggest that tight sandstone gas was produced by coal seam and carbonaceous shale in Upper Paleozoic in the Linxing area. The homogenization temperature of inclusion reflects the continuous accumulation process of tight sandstone gas, and the Cretaceous was the main period for gas charging. The monoclinal structure, maturity of source rocks and activity of underground water in this area are the important factors for secondary biogenic gas formation.

Biomass gasification of hybrid seed Miscanthus in Glasgow’s downdraft gasifier testbed system

Global energy problems, rise in CO2 emissions and their implications on climate change are well documented. Renewable energy provides a crucial role in reducing these emissions whilst providing sustainable energy; energy conversion of biomass forms a valuable part of a renewable energy portfolio, with capability for baseload provision, and gas and electricity production. Gasification is the thermochemical conversion of biomass (carbonaceous material) into producer gases. A small-scale throated downdraft gasifier was designed and manufactured at the University of Glasgow and built to easily assess the gasification performance under different conditions e.g. feedstock variety and with different instrumentation and control strategies. Various feedstock varieties of Miscanthus (OPM12, MxG, and OPM53) were gasified under the same equivalence ratio (ER 0.30). The elemental compositions of each Miscanthus varied with their genetic properties. A Gasifier Control Unit (G.C.U) was installed on the experimental gasifier to measure parameters: temperature, pressure, liquid flow and mass flow. The gasifier was operated in batch mode; to improve repeatability the throat, grate and assembly were cleaned after each experiment. The experimental work reported in this research is mainly focused on the comparative study and analysis of the producer gas compositions, carbon conversion efficiency, higher heating value (HHV), lower heating value (LHV), cold gas efficiency and gas yield with the different biomass feedstocks. The ultimate and proximate analysis was done for all Miscanthus varieties along with ash analysis. The major outcome of this research was to investigate the impact of feedstock variety on gasification performance and identify preferred Miscanthus varieties to grow at scale with optimised gasification.

Femtosecond-laser-induced plasma spectroscopy for high-pressure gas sensing: Enhanced stability of spectroscopic signal

Gas composition detection and analysis in high-pressure environments, such as those encountered in combustors, power plants, and planetary bodies, are important for scientific and engineering research. Conventional laser-based sensing using nanosecond (ns)-laser-induced breakdown spectroscopy (ns-LIBS) remains unreliable at elevated pressures because of the relatively high measurement uncertainty. To circumvent this problem, we propose to employ femtosecond-laser-induced plasma spectroscopy (FLIPS) to achieve a stable and reliable gas sensing at elevated pressures. A comprehensive study on the differences in the measurement quality of FLIPS and ns-LIBS for high-pressure nitrogen gas is conducted. The results show that the signal level and stability of ns-LIBS significantly decrease with the increase in pressure. In contrast, the signal level of FLIPS increases with the increase in pressure while maintaining the stability in the pressure range of 1–40 bar. In addition to the superior measurement stability, the FLIPS measurement provides a longer probe length (∼3 times compared to ns-LIBS) with a higher data acquisition speed (100 times compared to 10-Hz ns-LIBS).