Gas Quality Research Articles

The Bacharach Method: A Low-Cost Tool for Small-Scale Combustion Units’ Flue Gas Quality Control

Although current EU regulations, such as EU Directive 2015/1189 on the eco-design of solid fuel boilers and Directive 2015/1188, in accordance with the Machinery Directive 2006/42/EC, require manufacturers to meet specific emission requirements for CE marking, the routine and regular onsite testing of household heating appliances is still not mandatory in many EU countries. This research endeavour addressed this gap by evaluating the effectiveness of the Bacharach method as a rapid and cost-effective tool for assessing flue gas quality, particularly in terms of particulate matter mass concentration. This study also compared the results of the Bacharach method with those obtained from two commercially available portable analysers. The research outcomes demonstrate that the Bacharach method, in combination with an innovative evaluation approach, offers a viable solution, enabling the swift and economical assessment of flue gas quality with the primary objective of determining the boiler class according to the limits specified by standard EN 303-5 under operating conditions. The modified Bacharach method for measuring TSP in solid fuel-fired boilers provides qualitatively similar results to the commercially used SM500 and STM225 instruments. The modified Bacharach methodology was primarily developed for comparison to the boiler class 3 limit (i.e., 125 and 150 mg/m3). The study revealed that the modified Bacharach method, when applied to biomass-based boilers, exhibited higher accuracies in the case of classification into classes 3 and 4, whereas fossil fuel-based boilers demonstrated higher accuracy in the case of class 5 limits.

STUDY OF THE EFFECT OF THE COMBINATION OF HALOTHERAPY AND BREATHING GYMNASTICS IN CHILDREN WITH BRONCHIAL ASTHMA

Purpose. To date, there is no developed program and in-depth analysis of the complex impact of the effect of the combination of halotherapy and respiratory gymnastics in children with bronchial asthma, and the effect of its application on the disease has not been tracked. For this reason, referring to the successful results of the combined application of physiotherapeutic techniques, natural and reshaped physical factors in the recovery process in bronchial asthma in childhood, the following research goal was set: to implement the combined application of respiratory gymnastics and halotherapy for more effective rehabilitation program and optimal functional recovery in children with bronchial asthma and to track the effect of its impact. Material/Methods. The study was conducted from October 2018 to March 2020 in the city of Razgrad, Bulgaria, in the Resonance after-school training center. Results. The results show that properly conducted respiratory rehabilitation, combining the application of respiratory gymnastics and aerosol therapy, can contribute to the improvement of clinical indicators, reducing the frequency and severity of paroxysmal conditions, improving ventilation indicators, some gas parameters, physical capacity and quality of life. Conclusions. There are objective grounds for asserting that the tested physiotherapy program with an emphasis on respiratory gymnastics and halotherapy has a positive effect on the functional status of children with bronchial asthma and contributes to achieving independence in daily activities and improving their quality of life.

Characteristics and kinetics of in-situ catalytic cracking of biomass tar in a micro dual bed reactor

This research introduces a novel micro dual bed reactor, combining rapid pyrolysis in a top-down with a fluidized bed for biomass tar catalytic cracking assessment. The study initially examines the impact of reactor zones on biomass pyrolysis, followed by an exploration of thermal and catalytic cracking behaviors of in-situ biomass tars using three fluidizing media. It delves into the generation of cracking gas and tar cracking reaction kinetics, based on the evolutionary trends of the gas. The process involves two distinct stages (S1 and S2). In S1, olivine shows the highest tar conversion rates at 650 °C and 750 °C, while char peaks at 850 °C. In S2, char leads in conversion rate and reaction time, with a preference for CO and H2. Tar conversion rates at high temperatures follow the order char > olivine > sand, and reaction times vary as olivine > sand > char. Temperature affects tar cracking rates due to thermal and catalytic effects interplay. This study applies an integral method to solve the kinetics under varying conditions, providing insights into tar behaviors during both thermal and catalytic cracking. These findings support designing and optimizing tar removal units in biomass gasification, potentially reducing tar production and enhancing gas quality.

Interconnected pyrolysis and activation with in-situ H3PO4 activation of biochar from pear wood chips in a pilot scale dual fluidized bed

Interconnected pyrolysis and activation is a novel technology for combustible gas and biochar production in dual fluidized bed (DFB). The study proposed one-step and two-step methods for pyrolysis and activation of biomass in a pilot scale DFB with capacity of 100 kg/h. Physical and chemical activation occurred simultaneously in DFB system by phosphoric acid (H3PO4) impregnation pretreatment of pear wood chips, and flowing hot flue gas and steam. Stable operating parameters were observed for both methods. The one-step method was superior to the two-step method in terms of the pyrolysis gas quality, biochar pore distribution, micro- and meso-pores structures of biochar, while one-step method reduced the biochar yields. As an activation agent, H3PO4 increased the yields of biochar and pyrolysis gas, promoted formation of micropores and enriched the surface functional groups of biochar with increasing ratio of H3PO4. H3PO4 to biomass ratio of 1:5 reached the maximum biochar yield of 42.3 wt% and highest iodine adsorption value of 648.5 mg/g, increasing by 70.6 % and 90.3 % compared to the biochar without H3PO4 pretreatment, respectively. This DFB system facilitated the diversified use of fluidized beds and the co-production of biochar and product gas with energy saving and CO2 emission reduction.

Catalytic upgrading of Naomaohu coal pyrolysis volatiles over CaO catalyst

Catalytic upgrading of coal pyrolysis volatiles is one the promising way to achieve high quality tar and gas. In this study, catalytic upgrading of volatiles from Naomaohu (NMH) coal pyrolysis has been conducted in a two-stage fixed bed reactor using CaO as catalyst. The aim of this work was to investigate the catalytic effect of CaO on the gas and liquid product distribution, as well as the variations in gas and coal tar components. Simulated distillation and GC-MS analysis has been used to understand the distribution of tar component. On the one hand, CaO exhibits selective cleavage of large molecules, such as long-chain esters, leading to the production of aromatics through the processes of dehydrocyclization and aromatization. CaO has the ability to stabilize free radicals that are generated during the cleavage of large molecules, thereby promoting the formation of light aromatic hydrocarbons. Consequently, the light tar fraction (boiling point <360 °C) increased from 64.4 % to 74.6 %, while the heavy tar fraction (boiling point＞360 °C) decreased from 35.6 % to 25.4 % in the pyrolysis tar. The compounds with long ester chains in the tar composition decreased by 24.4 %. The content of light components, such as benzenes, naphthalene, and phenols, increased significantly with the increasing catalytic temperature. Specifically, the content of benzenes, naphthalene, and phenols increased by 11.83 %, 17.73 %, and 4.41 % respectively at the coal to CaO ratio of 1/0.5 and the catalytic temperature of 600 °C. On the other hand, the CaO absorbs the CO2 pyrolysis gas leading to an elevation in the concentration of CH4 and H2 in the pyrolysis gas. The concentration of CO2 decreased from 37.9 % to 16.58 % compared to without the catalyst while the concentrations of H2 and CH4 increased to 26.24 % and 31.15 % at the catalytic temperature of 450 °C. The CO2 absorption ratio reached a maximum value of 97.16 % at a coal to CaO ratio of 1/2. These findings suggest that the CaO catalyst beneficial both for improving the tar and gas quality.

Brackish Water, Phosphate Fertilization and Trichoderma in the Agronomic Performance of Beet Crops

The study hypothesis proposes that the use of Trichoderma, associated with fertilization with 100% of the recommended phosphorus, may mitigate saline stress and maximize the productivity and quality of the tuberous root. This study aims to evaluate the mitigating effects of phosphate fertilization and Trichoderma harzianum in beet plants under salt stress, by measuring the initial growth, leaf gas exchange, productivity and quality of the beet. The experimental design used was entirely randomized, in a 3 × 2 × 2 factorial scheme, referring to three doses of phosphate fertilization (25%, 50% and 100%), with and without the use of Trichoderma-based inoculation, and two levels of electrical conductivity of the irrigation water (0.5 and 6.2 dS m−1). Salt stress negatively affected the leaf area of the beet. The shoots’ dry mass was reduced as the electrical conductivity of the irrigation water increased, especially in the treatment with the 25% P2O5 dose. Salt stress reduced photosynthesis to a greater extent at the 25% P2O5 dose and in the absence of Trichoderma harzianum. Increasing the electrical conductivity of the irrigation water reduced transpiration and increased leaf temperature at the 25% P2O5 dose and in the presence of Trichoderma harzianum. The 25% P2O5 dose increased the stomatal conductance of the beet. The higher electrical conductivity of the irrigation water negatively affected water use efficiency, most significantly at the 25% P2O5 dose. Our data showed that the doses of 50% and 100% P2O5 were more efficient at increasing the productivity and quality of the beet, with the tuberous root diameter being higher under the lower electrical conductivity of the water and the absence of Trichoderma harzianum. The pH was high under the lowest electrical conductivity of the water, with a dose of 25% P2O5 and the absence of Trichoderma harzianum.

Study on pollutants detection in natural gas pipeline based on circular probe microwave resonance sensor (CPMRS)

Pollutants, such as black powder, are commonly found in natural gas pipelines and are considered undesirable. These pollutants not only degrade the quality of natural gas, but also contaminate compressor components and can even corrode and damage the pipeline, leading to serious safety hazards such as pipeline blockages. This paper proposes and investigates a novel circular probe microwave resonance sensor (CPMRS) to dynamically measure pollutants in natural gas pipelines at an early stage. The influence of the circular probe structure on the CPMRS performance and the optimal structural parameters of the CPMRS are studied using finite element simulation software. An experimental platform is then set up to evaluate the resonance of the CPMRS in different working conditions. The results show that the resonance frequency shift can reach up to 4.27 MHz for the mass flow rate of 12.54–78.69 mg/s. Additionally, the results demonstrate that the magnitude of the phase change of CPMRS is considerably greater than the magnitude of the amplitude change. The results also indicate that CPMRS is more sensitive to pollutants and more resistant to flow velocity perturbation than ordinary transmission probe microwave sensors.

Geochemical impact of biomethane and natural gas blend injection in deep aquifer storage

Biomethane is one of the main renewable gases available today to offset fossil gas and decarbonize the energy system. The EU is seeking to rapidly replace part of the natural gas usually stored in deep saline aquifers by biomethane which contains up to 10000 ppm of O2. This study presents for the first-time assessment of deep aquifers’ resilience to biomethane and natural gas blend injection into two sandstone reservoirs with different mineral paragenesis from the Paris Basin (France). Multiphase reactive transport modeling allowed to evaluate changes in gas and water quality, mineralogy and moreover, to identify major resilience properties of storage facilities necessary to buffer the oxygen reactivity and induced acidification coming from gas–water–rock interactions. In the presence of pyrite, the injected oxygen is consumed during pyrite oxidation and contributes to the acidification of the formation water close to the injection point. However, the injection of 1% mole fraction of CO2(g) contained in the gas blend is found to be the main acidification factor. The analysis of reservoir resilience showed three protection levels of pH buffering capacity, which can effectively mitigate an increase in oxygen content up to 1000 ppm: (i) calcite dissolution, (ii) plagioclase and clay dissolution and (iii) clay sorption capacity. Models predict that the gas blend injection could induce minimal but long-term change in the mineralogy without significantly impacting the global porosity. Overall, both sandstones can preserve the quality of the gas plume despite partial CO2(g) exsolution induced by the geochemical perturbation of the formations. The developed models will be used as a basis for assessment of renewable natural gas storage facilities in the long-term.

Diagnostyka stanu technologicznego gazociągów na podstawie składu transportowanych mieszanin gazowych

The efficiency of natural gas transportation hinges largely on the quality of technological processes involved. Imperfect separation process can lead to the liquid particles remaining in the gas and entering the transport systems, causing various technological issues with gas pipelines (clogging, hydrate formation, corrosion wear, etc.). The presence of mechanical particles in gas mixtures accelerates the degradation of metallic components of the transport system due to erosion. Additionally, the multiphase nature of gases contributes to complications during transportation, altering the quality indicators when different gas qualities are mixed. Consequently, the composition of gas mixtures, their mechanical particles, moisture, and other indicators, deviate non-linearly from their initial values. The technological condition of the main gas pipelines significantly impacts their discharge capacity and hydraulic characteristics. Failure to clean natural gas to current standards and requirements at production stations can result in condensation of water and hydrocarbon vapours in pipelines, leading to the accumulation of the liquid phase in the cavities of the pipeline and the formation of blockages due to hydrate compounds formation, the reduction of the cross-section of the gas pipeline or its complete blockage. Sediment accumulation on the inner surfaces of gas pipelines installed in complex geographical conditions adversely affects transportation system, increasing maintenance, energy, and transportation costs. Utilizing gas composition as an auxiliary tool (indicator) for diagnosing various technological processes and predicting transport parameters has been investigated in numerous research works in the oil and gas production industry.

In-situ electrochemical impedance analysis of a commercial SOFC stack fueled by real wood gas

The combination of solid oxide fuel cells (SOFCs) and wood gasification has the potential to significantly increase renewable electricity production and decrease emissions. Depending on the quality of the wood gas, degradation processes have a significant impact on the reliability and lifetime of the SOFC. Using electrochemical impedance spectroscopy (EIS) and subsequent distribution of relaxation times (DRT) analysis, the impact on the degradation of coupling wood gasification with a commercial SOFC stack is determined in this study. The thermal behavior of the SOFC stack under various operating conditions, as well as various synthetic wood gas mixtures classified by their hydrogen-to-carbon (H/C) ratio, was assessed. The decrease in the H/C ratio from 8 to 1, observed during syngas and real wood gas operation, leads to a rightward shift in the Nyquist plots, suggesting an increase in the SOFC stack's impedance. Correlations between variations in the H/C ratio and their effects on anodic electrooxidation, ionic conduction, gas transport, and diffusion were identified using DRT analysis to interpret the EIS results. By incorporating an upstream desulfurization system and ensuring an H/C ratio greater than 2, the coupling of biomass gasification with the SOFC stack was stable to degradation issues.

Pyrolysis of biomass to produce H-rich gas facilitated by simultaneously occurring magnesite decomposition

This study investigated how biomass pyrolysis varies with the different fractions of magnesite mixing into biomass. The pyrolysis occurred with simultaneous decomposition of magnesite without use of any gasification reagent, and was analyzed in terms of producer gas yield and quality. As magnesite fraction increased from 0 to 30 %, the yield of producer gas and its calorific value increased from 48.6 % to 66.3 % and 8.29 to 8.93 MJ/Nm3, respectively. The carbon and hydrogen conversion increased from 44.1 % to 60.7 % and 43.1 % to 66.2 %, respectively. The characterization results revealed that magnesite particles facilitated the conversion of fixed carbon and the thermal/catalytic cracking of tar to produce H-rich gas. The in-situ generated CO2 from magnesite decomposition could be reduced to CO/CH4 in the reductive atmosphere of the pyrolysis products. This study proposes the concept of converting low-energy–density biomass into gas without oxygen and provides a novel approach for producing H-rich gas from biomass.

Analysis of Gas Characteristics Produced in an Updraft Type Gasification Reactor with Various Gas Agent Flow Rates

Gasification is a process of converting compounds containing carbon to change both liquid and solid materials into combustible gaseous fuel (CO, H2, CO2, CH4 and H2O) through a combustion process with a limited air supply, namely 20-40% of the air stoichiometry. The aim of this research is to obtain syngas that is renewable natural gas quality. The gasification reactor used in this research has a reactor diameter of 600 mm and a reactor height of 1500 mm. Research on the characterization of the gasification process in updraft gasifiers made from horse manure using the thermal decomposition method where the gas agent used is air. Variations in the flow rate of the gas agent used are 10, 15, 20 and 30 lt/minute. The results of the research that has been carried out show that the greater the flow rate of the gas agent, the CO gas levels will increase with an average increase of 15%, however the increase in CO gas is followed by a decrease in CH4 gas levels, namely an average of 13%. Likewise, CO2 gas levels decreased by an average of 14%.

Utilizing pulverized waste polyvinyl chloride film as an alternative reducing agent for iron ore reduction

The research into using waste plastics as a substitute for coal powder and coke as a reducing agent has garnered significant attention, driven by various factors such as increased environmental concerns and growing interest in sustainable materials. This study investigates the process of carbothermal reduction using a mixture of waste polyvinyl chloride (PVC) and iron concentrate. Thermogravimetric analysis demonstrated that the heat-treated polyvinyl chloride products (PVC370) exhibited superior reaction properties compared to anthracite. Reduction tests indicated that PVC370-bearing pellets were less sensitive to temperature changes than anthracite-bearing pellets, highlighting a potential advantage of PVC370 in industrial applications. Moreover, the metallization ratio of PVC370-bearing pellets exceeded that of anthracite-bearing pellets before reaching 1150 °C. At a temperature of 1100 °C and a C/O of 0.8, the metallization ratio of PVC370-bearing pellets peaked at 83.17 %. During the reduction process of PVC370-bearing pellets, hydrogen (H2), carbon monoxide (CO), and hydrogen chloride (HCl) were efficiently released at relatively low temperatures. The efficiency of gas release in the reduction process could be attributed to certain factors, such as the composition or structure of the PVC370-bearing pellets. Notably, the quality of gasses generated during the reduction process of PVC370-bearing pellets is superior to that of anthracite-bearing pellets, even when considering chlorine content.

Compilations and updates on residual feed intake in sheep.

The increasing global demand for food and the strong effect of climate change have forced animal science to advance regarding new methods of selection in search of more efficient animals in production systems. Feed consumption represents more than 70% of the costs of sheep farms, and more efficient animals can increase the farmers' profitability. One of the main measures of feed efficiency is estimated residual feed intake (RFI), created in 1963 by Robert Koch for estimation in cattle and later adapted for sheep. Animals with negative RFI values (RFI-) are more efficient than animals with positive values (RFI+), with influence on the variables of performance, carcass quality and production of enteric gases. The RFI is the most common and accepted metric of the feed efficiency trait for genetic selection, since it is independent of growth traits, unlike the feed conversion ratio. The purpose of this review article was to present updated literature information on the relationship of RFI estimates with performance measures, molecular markers, greenhouse gas production and feed efficiency, the technical aspects and physiological basis of metabolic in sheep.

Effect of reaction conditions on pyrolysis performance of waste plastics loaded with Ni/ZSM-5 catalyst

Ni/ZSM-5 catalysts were prepared by uniformly loading the active metal Ni to ZSM-5 zeolite using excessive wet impregnation method, and the characterization tests of XRD, SEM, H2-TPR, and NH3-TPD were carried out. For the prepared Ni/ZSM-5 catalyst, the pyrolysis–catalytic reforming of waste plastics for gas production performance was explored under different reaction temperatures, steam-carbon (S/C) ratio, catalyst addition amount, and plastic type. The results showed that the gas production volume and gas quality of pure pyrolysis of HDPE and catalytic pyrolysis of Ni/ZSM-5 were improved with the increase of temperature. Given the thermal economy, the optimal pyrolysis temperature was 700 °C, the catalytic gas production was 900 mL, and the hydrogen concentration was 64.4 %. S/C ratio of 1.5 and plastic: catalyst of 1 was the best reaction condition, under which the gas production was 1020 mL and the hydrogen concentration was 65.1 %, respectively. In addition, an appropriate increase in the amount of steam and the addition of catalysts would greatly optimize the final gas production performance. However, excess steam and catalysts was unfavorable to the gas production of plastic pyrolysis, resulting in a waste of resources. Finally, as for the gas production of four plastics, LDPE had the best pyrolysis gasification effect with gas yield of 1040 mL and hydrogen concentration of 65.7 %. The order of catalytic pyrolysis effect of different plastics was LDPE > HDPE > PP > PS.

Research on the minimum detection limit for measuring high-purity gases by gas chromatography

Abstract At present, the application fields of high-purity gases (purity reached 99.999% and above) include the semiconductor manufacturing industry, chemical analysis, fuel cells, aerospace, medicine, etc., and the quality and purity requirements of high-purity gases are also getting higher and higher. As the only detector that can detect ppb-level trace impurities, the pulsed discharge helium ionization detector (PDHID) is the most used detector in the field of high-purity gases. The minimum detection limit of existing PDHID-related analysis methods is usually calculated theoretically. In order to verify the actual minimum detection limit of PDHID, a multi-group gas distribution system was used in this paper to dilute the permanent gas components in the high-purity gas, and the gas chromatograph with pulsed discharge helium ionization detector (GC-PDHID) was used to detect the obtained different concentrations of standard gases. The experimental results showed that PDHID possessed high sensitivity, good linearity, and a wide linear range. The actual minimum detection limit for the permanent gas components in the high-purity gas could reach the ng/g (ppb) level, which could realize the detection of ultra-low concentration samples, and further verify the actual minimum detection limit of PDHID. This experiment provides a reference basis for the analysis of trace gases in the gas industry, especially in industries such as high-purity and ultra-high-purity gases and gas for the electronics industry, and is of great significance in actual production work.

Combination of waste processing between MASARO plastic refinery unit and maggots technology

The evaluation of MASARO plastic refinery unit and maggots waste processing strategies’ efficacy, environmental impact, and economic analysis is at the center of the issue formulation in this study. Waste processing through MASARO plastic refinery unit requires incinerators, pyrolysis, and wet scrubber units. On the other side, maggots are used in waste processing because of their capacity to swiftly degrade the waste without negative impacts on the environment. Waste reduction is a parameter that can be used to measure the performance of waste processing. The percentages of waste reduction achieved by using MASARO plastic refinery unit can surpass 90% whereas maggots can range from 65.5% to 78.9%. The environmental impacts of MASARO plastic refinery unit and maggots technology are low. The flue gas qualities from MASARO plastic refinery unit are almost below threshold limits so it does not harm the environment. Likewise, waste processing using maggots has almost no negative impacts due to low emissions of CO2, CH4, SO2, and N-element. From an economic point of view, the MASARO process can provide an annual revenue of $3,840,000. Meanwhile, the anticipated annual revenue from waste processing using maggots is $55,000 if they are sold for $1000 per ton.

Experimental and feasibility study of bio-waste valorization through pyrolysis for energy and materials production in the concept of circular economy

The pyrolysis and co-pyrolysis characteristics of large abundant bio-wastes, namely date pits (DP), peanut shells (PS), coffee grounds (CG), and tea waste (TW) were investigated in detail. The TG/DTG and pyrolysis procedures were used to examine the thermal pyrolysis behavior of these agro-wastes and their blends (50%CG/50%DP, 50%CG/50%PS, 50%DP/50%PS, 50%TW/50% DP,50%TW/50%PS and 50%CG/50% TW by weight). The characterization of these feedstock has shown their suitability for energy and material valorization. Experiments were carried out in a batch pyrolysis at a medium heating rate of 10 °C/min. The goal was to identify the best combination aiming to produce either char or hydrogen-rich gas, which can contribute to the development of the circular bio-economy. It was demonstrated that pyrolysis favored the liquid product, fluctuating from 34.31% (TW) to 50.92% (DP), while the co-pyrolysis greatly increased the gaseous product, which ranged between 42.02% (TW-DP) and 55.17% (PS-TW). The blending of CG and PS resulted in heightened reactivity, leading to an enhanced generation of H2 (34.44%). The optimal mixture was found to be CG-TW, showcasing superior performance in terms of gas quality (38.39% H2) and yield (53.74%). This outcome underscores the potential of CG and TW as a synergistic blend for efficient hydrogen-rich gas production. The FTIR findings revealed that the recovered biochars have the potential to serve as solid fuels, biofertilizers, or carbon materials. Additionally, they could be used as eco-friendly precursors for chemical and related industries. By analyzing various waste mixtures and their respective pyrolysis properties, this research aims to contribute to the development of sustainable waste management practices as well as efficient energy and material production methods.

Cepair: an AI-powered and fog-based predictive CEP system for air quality monitoring

Air pollution is one of the influential problems threatening the environment and human health today. Therefore, it is critical to develop predictive systems for proactive decisions in solving this problem. Since the prediction of air pollution depends on several complicated factors such as the accuracy of meteorology reports, air pollution accumulation, traffic flow, and industrial emissions, the contribution of historical or real-time predictions to the solution of the problem is limited. To address the existing limitations, we propose a novel AI-powered and Fog-based predictive complex event processing system (CepAIr) for the prediction of future air pollution rates. CepAIr predicts the future air quality of pollutant gases using RNN, LSTM, CNN, and SVR models. Then, it sends the prediction results to decision-makers in an understandable format, enabling them to take proactive actions. Finally, we evaluate the performance of the CepAIr with SVR and DL models. Additionally, we examine CepAIr in terms of end-to-end network delay and measure its impact on the network. The extensive simulation results demonstrate that the CepAIr predicts future pollutant gas concentrations with DL models (especially with CNN) with a high success rate while guaranteeing minimum end-to-end network delay.

الخصائص الفيزيائية والكيميائية الكاذبة والديناميكية الحرارية للغازات الطبيعية

Physiochemical, pseudocritical, pseudoreduced and thermodynamic properties play an important role for determination natural gas quality and specifications. Nowadays natural gas regard as one of the importance natural source of energy supply due to its high heating value, clean source, no emissions and environmental friendly. In addition, it began to replace the oil as a fuel in various purposes and as essential feed for petrochemical industries. Consequently, the different properties of natural gas mixtures must be investigated to determine their specifications. This study was aiming to distinguish these properties using correlations and mathematical models for assessment. These properties include the physical such as molecular weight (M_w), density(ρ), specific gravity(γ), compressibility factor (z), gas viscosity (μ_g), gas formation volume factor (B_g), gas thermal compressibility (C_g) and water content as well as pseudocritical pressure (p_pc), pseudocritical temperature (T_pc), pseudoreduced pressure (p_pr), pseudoreduced temperature (T_pr). Also, the thermodynamic properties e. g. Gross heating value, thermal conductivity, and specific heat of natural gas mixtures were determined. The study has been conducted on the natural gases of Zelten, Al Ragoba, Al Hotaiba gasfields and Al Braiga terminal to predict and estimate the physical, pseudocritical and thermodynamic properties by using correlation and mathematical models methods. The obtained results revealed that there is a variance between these properties of the natural gas mixtures, which may be attributed to the chemical compositions of components and their behaviors. On the other hand, these characterizations can be used as guide to understand the gases behavior during the different operations and natural gases treatment processes. Keywords: Natural gas, physiochemical, pseudocritical, pseudoreduced thermodynamic properties, and correlations