Gas Calorimeter Research Articles

Measuring the enthalpy of combustion of methane gas and establishing the model function to perform comprehensive uncertainty calculations

Natural gas is a plentiful and adaptable energy source among other gases that is used all over the world with an increasing demand nowadays. It is therefore of utmost importance to measure the energy content of the natural gas with high precision for both users and sellers. In this study, methane gas, the main component of natural gas, was combusted using the reference gas calorimeter developed at TUBITAK UME (The Scientific and Technological Research Council of Turkey) - (National Metrology Institute) to determine the enthalpy of combustion. The objective was to measure the enthalpy of combustion of the methane, perform a detailed uncertainty calculation and to compare the enthalpy of combustion of the methane specified in ISO 6976:2016 with the obtained experimental results. The reference gas calorimeter was designed using the temperature, mass, power, flow control, waste water absorption, and waste gas measurement systems with the highest precision and circulating water bath with temperature control insulated so as not to exchange heat from the external environment. All measurements were performed with the instruments having calibration certificates. Experiments were carried out at the temperature of 298.15 K and a constant pressure (101.325 kPa) using the methane with a purity of 99.995 % as a reference gas. The mass of the burnt methane in combustion process was approximately 10-3 kg. As a consequence of the measurements, mean experimental enthalpy of combustion was obtained as −55518.2 kJ kg−1 with the error of 0.2 % (k = 2). The evaluations indicated that the largest source of error in the enthalpy of combustion measurements originated from the temperature and mass measurements.

Design and fabrication of convergent exhaust gas calorimeter

The exhaust gas calorimeter is a heat exchanger to improve the heat transfer rate and limits the scattering of exhaust gases. In this study reduction in the amount of heat through emission is been identified and related to the existing model to get comparatively better results. Various Calorimeter design and testing has been done using analytical software. Compared between to get better results than existing one. After modification in design, the modified calorimeter has been fabricated. It demonstrates that the total heat transfer rate is higher and the heat transfer rate per unit area is greater than the current rate. Finally, we calculated and experimentally verified that the rate of heat transfer and the total rate of heat transfer was more efficient than the existing one and in this modified design of exhaust gas calorimeter it is observed that the density of materials increases hot gases is been reduced by elevating the temperature of these gases which leads to limiting scattering of gases like NOx, CO (Nitrogen oxides, Carbon Mono oxide), etc., scattering directly into the atmosphere.

Magnetization of bioethanol-gasoline fuel blends for development combustion energy and reducing exhaust gas emissions

The effect of the magnetization field on molecular interactions of the bioethanol-gasoline fuel blends was investigated. This technique was promoted to escalate both the increase in combustion energy and reduce emissions in the internal combustion engine. The bioethanol and gasoline fuel are used for the single-cylinder four-stroke engine with different mixtures, namely E0, E10, E20, and E30, serially. Distinguish of electromagnetic field strength with various intensity was given into the fuel by lower than 1,500 Gauss. The absorption intensity and the functional groups of the fuel molecules are characterized in detail by Fourier Transform Infra-Red (FTIR) spectroscopy. The exhaust gas emission and the fuel blends energy are performed using a gas analyzer and calorimeter bomb. By increasing the magnetic field, the de-clustering of the fuel molecules is demonstrated by growing the absorption intensity to be advanced. There is no change in the chemical composition of the fuel as the magnetic induction was enforced. Reduction of namely Carbon monoxide (CO), Nitrogen monoxide (NO), Nitrogen oxides (NOx), and Sulphur Dioxide (SO2) gas emissions was attained to be 29 %, 25 %, 26 %, and 31 % using a magnetic field of 1,419.57 Gauss, respectively, compared to gasoline fuel without magnetic condition. The greater reduction occurs by employing E30 fuel with the same magnetic intensity, achieved up to 38 %, 42 %, 70 %, and 63 %, regularly. The magnetization treatment leads to improved combustion quality with efficiency increases up to 11.32 %. It contributes to perfect combustion in a single-cylinder four-stroke engine system. Reducing gas emissions can also bring a good environmental impact in the life, although the heat energy gradually deteriorated as the fuel utilized more bioethanol blends

Improvement of reference gas calorimeter to measure the gross calorific value of the reference methane gas having high purity (99.995 %) and calculation of uncertainty

Improvement of reference gas calorimeter to measure the gross calorific value of the reference methane gas having high purity (99.995 %) and calculation of uncertainty

Modeling of the Construction for the Combustion Chamber of the Gas Calorimeter in the Aspect of Exhaust Gas Homogenization in the Measuring Space

The assessment of the physicochemical parameters of fuels is particularly important in energy generation processes implemented using combustion processes. The calorific value of the fuels used is important in these processes. The calorific value of fuel is the basic parameter from which the mass of fuel necessary to generate a certain amount of energy results. Calorimeters are used to determine the calorific value of fuels. The subject of analyzes is the conceptual design of the calorimeter for gaseous fuel testing. A special element in the construction of the calorimeter is the combustion chamber. In its initial part, the gaseous fuel oxidation process is carried out, and in the final part, the required parameters are measured. In order to obtain high accuracy in the measurement of selected thermodynamic parameters, it is necessary to ensure homogeneity of the exhaust gases flowing in the measurement space. For this purpose, the construction of the combustion chamber was developed and simulation tests aimed at homogenization of exhaust gases in the chamber measuring space were carried out. An example of the construction and the tests carried out are provided in this article.

Pilot-scale hydrogen generation from the hydrolysis of black aluminum dross without any catalyst

This study presents a sustainable method for the production of hydrogen gas without adding any catalyst from the hydrolysis of black Al dross. A pilot-scale experimental setup consisting of a reactor, a condenser, and control and measurement devices was constructed to perform chemical reactions and physical measurements. The dross used in experiments was not activated by any process and can be found in facilities (Al production plants or die casting factories) with a grain size lower than 400 μm. The chemical composition revealed by XRF showed that the black dross contained 41.96% Al. Major and minor crystalline phases present in the sample were detected by XRD. A set of experiments was performed to investigate the effects of gravimetric dross to water ratio, pH value, initial water temperature, the pressure of the reaction mixture in time for H2 synthesis. 120 L of gas were maximally produced after reacting 1 kg of Al dross with 2 kg of hot tap water at 100 °C. The H2 purity of the gas mixture and the calorific value of the mixture were respectively measured by gas chromatography and gas calorimeter as 93.24% and 2375 kcal/m3. After hydrolysis of the Al dross, XRD, SEM, and EDX analyses revealed the formation of hydrolysis products and their morphology. This showed that the resultant mixture tends to become harmless and can be used for various fields of the industry as a by-product.

A portable calorimeter for measuring the calorific value of natural gas

Abstract
 Natural gas quality assessment is a relevant issue. A critical analysis of calorimeter designs for measuring the calorific value of natural gas was carried out. The most common methods for determining the calorific value of natural gas are as follows: direct by gas calorimeters; indirect by gas chromatographs; indirect, based on correlations. The advantages of isoperibolic calorimeters of measuring calorific value of natural gas directly in the consumer’s conditions are substantiated. The design of a portable calorimeter containing a thermostated shell, calorimetric tank, Peltier element with tank, circulating pump, gas burner, thermostat systems, metered supply of natural gas and air, fuel ignition, sensors, combustion analyzer and control and measurement unit, was developed. The geometric dimensions of the calorimetric tank are optimized, materials and technologies of manufacturing parts are specified. The metrological analysis of the developed portable calorimeter was carried out. A method for measuring the calorific value of natural gas directly in the conditions of household consumers and transport enterprises was developed. The results of testing the prototype calorimeter in the laboratory confirmed its high performance and metrological characteristics, and the deviation of the measurement of the calorific value of natural gas from that determined using a gas chromatograph was 0.6%.

Advancements in the development of the isothermal gas calorimeter based on Alexandrov’s principle

The Isothermal gas calorimeter based on Alexandov’s design is a robust and versatile device that can be used for the determination of the heat of combustion of new emerging gas mixtures, such as biogas, biomethane or hydrogen enriched gases. This calorimeter is easily adaptable to these new gas mixtures which, due to the large range of densities and compositions, challenge other more expensive techniques used for this purpose, namely gas chromatography. New technologies (new mass flow controllers and simulations heater) were implemented and the performance under the new circumstances analysed. The analysis showed relevant weaknesses that need to be addressed for an optimal performance for the new gas mixtures, such as heat losses, or the selection of the working fluid. The uncertainty budget performed under the new developments showed that the calorimeter can determine the calorific value of gas mixtures with a relative uncertainty lower than Ur = 0.5% (k = 2). However, this value will be improved further once the weaknesses discovered in the performed analysis are addressed.

Metrological Assurance of Gas Calorimeter and Wobbe Index Analyser

The paper describes research on metrological assurance of such measuring instruments as gas calorimeters and Wobbe index analysers. The purpose of the performed research is development of reference materials for gases with certified value of net volume-basis calorific value traceable to Russian state primary standard. Input set of candidate gases is hydrogen, methane, ethane and propane, as well as the target uncertainty of lower volumetric combustion energy value equal to 0,3 % – both were selected basing on results of metrological characteristics analysis of calorimetric equipment. The certified value of lower volumetric combustion energy is traceable to the State Primary Standard of combustion energy, specific combustion energy and volumetric combustion energy units GET 16. The certified value of selected gases and the uncertainty of this value were estimated with usage of comparing calorimeters for the combustion of high- and low-calorie gases «USVG» and «USNG» included in GET 16. Results obtained during investigational study and reference materials characterisation confirmed the stated accuracy. The continuance in prospect may allow development of reference materials for gas imitating mixtures of natural and casing-head gases as well as include Wobbe index in the list of certified characteristics.

Energetic Characterization of Faujasite Zeolites Using a Sensor Gas Calorimeter

In addition to the adsorption mechanism, the heat released during exothermic adsorption influences the chemical reactions that follow during heterogeneous catalysis. Both steps depend on the structure and surface chemistry of the catalyst. An example of a typical catalyst is the faujasite zeolite. For faujasite zeolites, the influence of the Si/Al ratio and the number of Na+ and Ca2+ cations on the heat of adsorption was therefore investigated in a systematic study. A comparison between a NaX (Sodium type X faujasite) and a NaY (Sodium type Y faujasite) zeolite reveals that a higher Si/Al ratio and therefore a smaller number of the cations in faujasite zeolites leads to lower loadings and heats. The exchange of Na+ cations for Ca2+ cations also has an influence on the adsorption process. Loadings and heats first decrease slightly at a low degree of exchange and increase significantly with higher calcium contents. If stronger interactions are required for heterogeneous catalysis, then the CaNaX zeolites must have a degree of exchange above 53%. The energetic contributions show that the highest-quality adsorption sites III and III’ make a contribution to the load-dependent heat of adsorption, which is about 1.4 times (site III) and about 1.8 times (site III’) larger than that of adsorption site II.

A study on the load-dependent enthalpy of adsorption and interactions in adsorption of C5 and C6 hydrocarbons on zeolites 13X and ZSM-5 and an activated carbon

Abstract In a systematic experimental work, the adsorption of linear, branched and cyclic C5 and C6 hydrocarbons on the zeolites 13X-APG and HiSiv 3000 and the activated carbon Norit R1 Extra is studied. By simultaneous measurement of adsorption capacities and load-dependent enthalpies of adsorption using a self-developed sensor gas calorimeter a deep knowledge about the energetic strength of interactions in adsorption is gained. A special focus is laid on the discussion of the influence of pore geometry and surface chemistry of the adsorbents as well as the molecular structure and binding types of the adsorptives used. Depending on the pore geometry and the surface chemistry of the adsorbents, the load-dependent enthalpies of adsorption show different shapes. While the enthalpies of adsorption on the Faujasite zeolite increase with loading, they are independent of loading on the ZSM-5 zeolite and decrease on the activated carbon. On both zeolites the cyclic and branched adsorptive molecules show lower enthalpies of adsorption compared to the linear molecules due to a less favorable arrangement on the surface. On activated carbon, the enthalpies of adsorption of linear and cyclic hydrocarbons are comparable and significantly higher than those of branched hydrocarbons. For molecules with C=C double bonds only 13X-APG showed higher enthalpies of adsorption and thus stronger interactions.

First experimental comparison of calorific value measurements of real biogas with reference and field calorimeters subjected to different standard methods

This study presents the first comparison of experimental calorific value measurements of real biogas performed with three different calorimeters: one reference gas calorimeter developed at the French metrology institute (LNE) and two field calorimeters (Union Instruments CWD, 2005 CT and Cutler Hammer Calorimeter) at the German metrology institute (PTB). All measurement results obtained for calorific values agree within their measurement uncertainties. Uncertainties vary from 0.2% to 2.0% (coverage factor, k = 2) depending on the calorimeter and calibration procedure.Two different standards (DIN 51899 and ISO 6143) were used to calibrate the field calorimeters and these have been compared. This comparison focuses on the calibration procedure, calibration frequency, number and composition of calibration gases and evaluation algorithm.

Calorific value of biomethane: Comparative measurements using reference gas calorimeters

The first comparison of traceable measurements taken using two reference gas calorimeters was performed by LNE and PTB. The superior calorific values (SCVs) of three different biomethane samples were within the assessed uncertainties of approximately 0.1 %.

Measurement of the Calorific Value of Methane by Calorimetry Using Metal Burner

With the diversification of natural gas origins and variations in natural gas compositions, the accurate measurement of the calorific value of natural gas has become a very important issue for the gas industry and standardization. Korea Research Institute of Standards and Science is developing a standard gas calorimeter based on the isoperibolic technique. This work describes the details of the experimental apparatus and procedures of the developed gas calorimeter along with the measurement results for the superior calorific value of methane at $$25\,^{\circ }\hbox {C}$$ . A burner made of stainless steel was used for the first time in this type of calorimeter, and the potential application of a metal burner to a gas calorimeter was investigated. Eight measurements were performed, and the deviation from international standards was 0.16 %. The deviation was mainly caused by the measurement of the burned methane gas. The measurement results show that the metal burner may potentially be employed in a gas calorimeter.

Investigation of load-dependent heat of adsorption of alkanes and alkenes on zeolites and activated carbon

To investigate the load-dependent heat of adsorption a sensor gas calorimeter was developed which allows the simultaneous measurement of adsorption capacity and heat of adsorption in porous materials. A commercially available volumetric measurement device was extended by a newly developed calorimetric measuring cell. Using this apparatus, the load-dependent heat of adsorption of alkanes and alkenes on the zeolites 13X-APG and HiSiv 3000 as well as on the activated carbon Norit R1 Extra was investigated. On all three adsorbents the heat of adsorption increases with chain length of the hydrocarbons. On HiSiv 3000 and Norit R1 Extra both load and heat of adsorption for all investigated alkanes and alkenes of the same chain length are very similar due to similar interactions with the adsorbent surface. Presumably dispersion interactions dominate adsorption in these systems. Contrary to these findings on 13X-APG higher loads and enthalpies of adsorption for alkenes than for alkanes occur. These higher heats of adsorption can be attributed to the energetically more attractive quadrupole-cation interactions between the double bond of alkenes and the cations of the zeolite.

Comparison of traceable methods for determining the calorific value of non-conventional fuel gases

Energy-content measurements by direct methods (such as calorimetry) are used to validate the indirect method (from gas composition obtained by gas chromatography) which is generally adopted by grid operators for on-site gas control. A primary reference gas calorimeter and three field calorimeters were used for the first time to measure accurately the energy content of non-conventional gases (biogas and coal mine methane). The gas mixtures for this study were prepared by gravimetry and comprised three binary mixtures containing carbon dioxide and (up to 80 mol-%) methane, three ternary mixtures containing carbon dioxide, (up to 70 mol-%) methane and (up to 0.3 mol-%) hydrogen sulphide as well as a ten-component mixture with a methane content of approximately 64 mol-% which represents a typical coal mine methane. Associated uncertainty calculations were developed for each instrument and are presented here. Traceability of the measurements to the SI units is ensured in reference calorimetry, as calibration is accomplished by electrical simulation based on the Joule effect in order to obtain the heat capacity of the entire system. The results obtained with the four calorimeters are compared with each other and also with results calculated from the indirect method that is based on gas chromatography. Uncertainties (k = 2) between 0.07 and 0.49% for the reference gases were obtained with the reference calorimeter, while uncertainties for the field calorimeters range between 0.18 and 2.48% for the same mixtures. Compared to the usual standard deviation observed by gas chromatography for a multi-component gas mixture of about 1%, it is demonstrated that the calorimetric method, although rarely used for non-conventional gases before, is appropriate for energy-content measurements of gases originating from renewable energy sources.

Traceable measurement and uncertainty analysis of the gross calorific value of methane determined by isoperibolic calorimetry

As methane is the major component of natural gas and non-conventional gases as biogas or mine gases, its energy content has to be measured accurately regardless of its production site for fiscal trading of transported and distributed natural gas. The determination of calorific value of fuel gases with the lowest uncertainty can only be performed by direct method with a reference gas calorimeter. To address this point, LNE developed a few years ago an isoperibolic reference gas calorimeter according to the Rossini’s principle. The energy content Hs of methane of purity 99.9995% has been measured to 55 507.996 kJ kg−1 (890.485 kJ mol−1) with an expanded relative uncertainty of 0.091% (coverage factor k = 2.101 providing a level of confidence of approximately 95%). These results are based on ten repeated measurements and on the uncertainty assessment performed in accordance with the guide to the expression of uncertainty in measurement (GUM). The experimental setup and the results are reported here and for the first time, the fully detailed uncertainty calculation is exposed.

Wobbe Index Determination of Cattle Dung Biogas

This paper is aimed at determining the Wobbe Index (W I) of cattle dung biogas which is the amount of energy delivered to a burner through an injector or orifice especially during combustion. The biogas was produced by anaerobic digestion of cattle dung in a batch digester within two weeks. Pressure and temperature of the digester were monitored at 12 noon daily. The analysis of the combustible biogas using thermal conductivity detector (TCD) revealed CH4 at 0.562, CO2 0.395, H2S 0.018, CO 0.019 and 0.005 moles for NH3 by volume. Its calorific value (C V) using gas calorimeter Junkers was 19.5 MJ/m. The cumulative specific volume of the biogas rose from zero through day 1 to 0.622732 m/kg on the sixth day before recording daily marginal increments with the rest of the days of incubation. The relative density of the biogas also had a sharp rise on the second day at 5.039208 before dropping to 2.51126 and then gradually decreased daily to the end of digestion. The Wobbe Index equally rose from zero on the first day through to 12.08434 MJ/m, 14.07783 MJ/m and 15.87665 MJ/m on days 2, 3, 4 and 5 respectively after which it had logarithmic increments. The volatile solids destroyed also recorded logarithmic rise while the bacterial growth rate followed the zigzag pattern as those of internal energy and enthalpy. It is therefore concluded that parameters like the cumulative specific volume and Wobbe Index increased throughout the incubation period while those that are directly temperature dependent varied with the temperature of the digester.

Fuel Characteristics of Some Locally Available Biomass as a Potential Gasification Feedstock for Thermal Application

The acquisition of calorific values and CHN/O analysis have been performed for 10 locally available biomass samples (Delonix regia, Azadirachta indica, Ficus lepidosa, Dalbargia sissoo, Psidium guajava, Zizyphus mauritiana, Artocarpus heterophyllus, Moringa oleifera, and Polyalthia longifolia) and Bambusa tulda. Elemental analysis (CHN/O) of a biomass gives rise to estimation of its empirical biochemical formula. On the basis of average calorific values, oxygen and hydrogen contents in chemical formula against unit carbon atom of these biomass samples, the best biofuel was examined for gasification in a 10 kWthermal laboratory based down draft gasifier. It was observed that Psidium guajava had the highest calorific value (18.403 MJ kg–1), followed by Bambusa tulda (18.401 MJ kg–1), and the least was for Ficus lepidosa (15.952 MJ kg–1). These calorific values were obtained with an automatic bomb calorimeter. Against one atom of carbon, Bambusa tulda has minimum 0.599 fractions of oxygen atoms and 1.684 hydrogen atoms. The corresponding values for Psidium guajava is 0.608 (oxygen) and 1.752 (hydrogen). However, Delonix regia has highest hydrogen (1.866) contents. Nitrogen contents for all the samples are of course very small. Psidium gujava, Bambusa tulda, and Dalbargia sissoo were gasified in a 10 kW thermal downdraft gasifier; the producer gas thus generated had calorific values (4.6, 4.55, 4.50) MJ/Nm–3 as measured with a Junker Gas Calorimeter.

Characterization of syngas produced from MSW gasification at commercial-scale ENERGOS Plants

Characterization of the syngas produced in the gasification process has been performed at commercial-scale Energy-from-Waste plants under various conditions of lambda value and syngas temperature. The lambda value from the gasification process is here defined as the ratio of the gasification air to the total stoichiometric air for complete combustion of the fuel input. Evaluation of the syngas calorific value has been performed by three different methods, i.e., estimation of the syngas calorific value from continuous in-line process measurements by mass and energy conservation equations, measurement of the syngas composition based on gas chromatography and calculation of the Gross Calorific Value from the measured composition, and direct continuous measurement of the calorific value using based on gas calorimeter.