Gas Calorimeter Research Articles

Uncertainty analysis of theoretical methods for adiabatic temperature rise determination in calorimetry

The main methods for the determination of the temperature rise in calorimetric experiments corrected of heat losses to surroundings (called adiabatic temperature rise) are described thereafter. This corrected temperature rise is obtained analytically from experimental temperature–time curves. The general scheme reported by Henri Regnault and Leopold Pfaundler for the first time in the 19th century is considered as the basis for all methods elaborated afterwards. A bibliographical study raised five methods including Regnault–Pfaundler’s. These methods have been applied on five experimental temperature–time curves obtained with an isoperibolic reference gas calorimeter at the French national metrology and testing institute (LNE) on combustion of pure methane. This paper deeply details a new analytical method elaborated at LNE exposing best heat transfer phenomena representation occurring in the water bath calorimeter. A comparative study of the five methods of the temperature rise determination and of their associated uncertainties is here presented.

Thermal behaviour modelling of a reference calorimeter for natural gas

The French National Metrology and Testing Institute (LNE) build an isoperibolic reference gas calorimeter to measure the calorific value of natural gas with a high level of accuracy with the collaboration of the R&D Division of GDF-Suez. With 3D numerical modelling tools, GDF-Suez developed a comprehensive and refined model of the complete calorimeter geometry and evaluated the heat flux sources to reproduce the thermal behaviour of this calorimeter. The objectives are to optimise the thermal homogeneity and to maximize heat transfer to the water bath. The accurate assessment of the different thermal fluxes transferred to the water bath was performed based on a complete simulation of the combustion of the fuel gas in the burner. The numerical model results fit quite closely the experimental thermal behaviour of the calorimeter. The energy balance shows that approximately 90% of the total energy is absorbed by the water bath and about 10% by the calorimetric walls with a weak contribution of the radiative heat transfer to the calorimeter vessel. A comparative study between the numerical and experimental results confirms both that the geometries of the calorimeter vessels and the glass burner are adequate. The new refined geometric model validates also the location of the thermal sensor in the bath. The expected outcome of both experiments and thermal modelling is to decrease the uncertainty of the calorific value measured with this standard combustion calorimeter.

New French reference calorimeter for gas calorific value measurements

The direct measurement of gross calorific value (GCV) of gas with the lowest possible uncertainty can be performed with a reference gas calorimeter. LNE is currently developing an isoperibolic reference gas calorimeter. An exhaustive description of this calorimeter (set up and raw data analysis) for natural gas calorific value measurements is here described. A repeatability study of GCV of methane performed with a prototype version and first tests to reduce the unburned methane dragged with the burned gases are also presented. Calculation method of GCV is detailed and the improvements carried out on the different parts of the calorimeter (burner, vessels, sensors, etc …) are highlighted.

Recent advances of planar silicon APD technology

Radiation Monitoring Devices previously reported to have fabricated, using a planar processed, deep diffused silicon avalanche photodiodes (APDs) and position sensitive APDs (PSAPDs) that can be used for direct or scintillation-based spectroscopic and imaging applications. We have developed high gain (∼1000), high quantum efficiency (40–70% in the 200–900 nm region) at unity gain, relatively low noise, and magnetically insensitive APDs up to 45 cm 2 in area and PSAPDs up to 2.8×2.8 cm 2 in area. These detectors have begun to be implemented in applications such as positron emission tomography (PET) and single photon emission computerized tomography (SPECT) for medical imaging, high-energy physics experiments as water Cherenkov detectors and liquefied noble gas calorimeters, and receivers for long-range optical communication at near infrared (IR) wavelengths (1064 nm). Also, our PSAPDs have been combined with photocathode structures, similar to a photomultiplier tube (PMT), to fabricate hybrid devices. Here, we present a small review and a sample of results showing various applications utilizing our planar processed APDs and PSAPDs.

Dynamic calibration of a sensor gas calorimeter for measurement of heat generation rates during kinetic of adsorption experiments

A procedure for dynamic calibration of a sensor gas calorimeter, resulting with a calibration transfer function, instead with a calibration line, is presented. The main factors influencing the calibration transfer function have been assessed. The calibration transfer function enables measurement of the heat generation rates during adsorption, necessary for obtaining a complete picture about adsorption kinetics.

Estimation of the uncertainty for an isothermal precision gas calorimeters

The paper presents a brief description of a new method of measurement of the heat of combustion of gases and the design of a new gas calorimeter. The results of measurements of the thermal power and the heat of combustion of methane are analyzed with the aim to determine their uncertainties. It is proposed to divide the sources of uncertainty in three groups depending on the method of their processing. The investigations carried out prove the correctness of the measurement of both the thermal power and the heat of combustion of methane. The following values of the uncertainties of the heat of combustion of methane were determined: the relative standard uncertainty Type A ≤0.02% and the combined relative standard uncertainty ≤0.04%. The obtained results permit recommending the proposed gas calorimeter as a prototype of a standard gas calorimeter.

Design and Study of Gas Calorimeter for Absolute Measurements of the Combustion Heat of Natural Gas

A novel burning calorimeter design based on a heat pipe is presented. A circuit for automated control over operation of the proposed device is considered. The stability of the results is assessed. Several accessory parameters affecting the reproducibility of measurement results are evaluated. One of recent designs of the KTT-7 calorimeter, based on a thermosiphon, is analyzed. The uncertainty in heat power measurements on KTT-7 is evaluated.

Sintering of steel parts in endothermic gas and nitrogen-hydrogen atmospheres: J.G.Marsden et al. (Air Products and Chemicals Inc, USA.)

The design and testing of a new isothermal flow gas calorimeter is described. The calorimeter achieves complete combustion of the natural gas at temperatures from 400 to 500°C using a bed packed with a proprietary catalyst. The catalyst is 100% efficient for mixtures containing all of the typical natural gas components (C1-C6). The calorimeter assembly consists of a flow reactor that is suspended in a high temperature air bath. The temperature sensors for both reactor and shield temperature measurement or control are Pt RTDs. The gas is delivered by a cycling sample loop with constant volume and a lean gas/air mixture is supplied to the reactor. The gas sample net heating value (NHV) is determined from the gas flow rate required to maintain a constant reactor temperature. The water content in the exhaust is measured to obtain the gross heating value (GHV). All operations of the calorimeter including periodic calibration and reporting of heating values, specific gravity, and compressibility data are automated.The calorimeter makes energy measurements with an accuracy of ±1 BTU ft−3 and a precision of 0.5 BTU ft−3 for gas samples having gross heating values ranging from 800 to 1200 BTU ft−3. The calorimeter measures both the net and gross heating values. The mol. percent inerts, specific gravity, and compressibility are calculated by use of empirical correlation equations relating these properties to the net and gross heating values. The gas calorimeter has been packaged for field operation and operation in areas with potentially combustible atmospheres. The field performance of the gas calorimeter is compared with both an on-line gas Chromatograph and a Cutler-Hammer calorimeter.

Present state and trends in the development of combustion calorimetry

Modern bomb and gas calorimeters produced in Russia and abroad are reviewed. The main trends and ways of improving bomb calorimeters are described in retrospective form. Problems and aims in the area of gas calorimetry are considered.

Beam tests of “SPACAL”-type modules for a high-pressure gas calorimeter

High-pressure gas modules with cylindrical ionization chambers for a Very Forward Calorimeter (VFC) were constructed and tested in the U-70 electron beam of IHEP (Protvino). The read-out amplifiers were used in a remote mode (3 m long cables were used to connect the detector to the amplifier). The module performance was tested in the shower energy range 10–30 GeV employing different gas mixtures (Ar + CH 4, Ar + CF 4 and pure CF 4) at the pressure of 20–40 atm. The energy resolution σ(E) E = 18% is reached at the angle of 5.7° for 30 GeV incident electrons. The design was found to be adequate for a future use at LHC.

Metrological specifications for natural-gas quality

The paper discusses the reasons for disagreement of the consumers and suppliers of fuel. The relative errors of working gas chromatographs and calorimeters are compared as used for determining the heat of combustion of natural gas. Metrological specifications are drawn up for the quality of natural gas and the level of standard, reference, and working gas chromatographs. Recommendations are made on elimnating the disagreements relating to natural gas. Ways are indicated of increasing the accuracy in determining the heat of combustion and relative density of natural gas.

The CDF Upgrade

The Collider Detector at Fermilab (CDF) is a general purpose detector used to study the world`s highest energy p{anti p} collisions at the Fermilab Tevatron. Upgrades to CDF to enable it to function as the Tevatron evolves are described. The upgrade plans are to: (1) Replace the plug and forward gas calorimeters with new scintillator-based calorimeters. (2) Replace the Central Tracking Chamber with a new device with shorter drift distance (Central Outer Tracker). (3) Replace the silicon vertex detector with a longer double-sided device with faster readout. (4) Add a new Intermediate Forward Tracker between the silicon vertex detector and the Central Outer Tracker to enhance pattern recognition capability at high luminosities and to provide tracking in the region 1.0 {le} {vert_bar}{eta}{vert_bar} {le} 2.0. (5) Upgrade the front-end electronics, trigger and data acquisition systems to accommodate data collection with shorter bunch spacing and higher rates.

R&D and mass production of a scintillating tile/fiber system for the CDF plug upgrade EM calorimeter

The plug calorimeter of the Collider Detecor at Fermilab (CDF) [CDF Collaboration, Nucl. Instr. and Meth. A 271 (1988) 387 will be upgraded, replacing the existing gas calorimeter by a scintillating tile/fiber calorimeter. We have completed R & D for the CDF plug upgrade EM calorimeter. We describe the results of the R & D leading to the final design of the tile/fiber system for the calorimeter.We completed the whole production of the tile/fiber system in February 1994. To control its quality, we performed various quality tests during mass production. The tests and results are reviewed.

A scintillating tile/fiber system for the CDF plug upgrade EM calorimeter

The plug calorimeter of the Collider Detector at Fermilab (CDF) [1] will be upgraded, replacing the existing gas calorimeter by a scintillating tile/fiber calorimeter. We have completed R&D for the CDF plug upgrade EM calorimeter. We describe the results of the R&D leading to the final design of the tile/fiber system for the calorimeter. Kuraray SCSN38, Kuraray Y11 and PET film (E65) were chosen as materials for scintillating tiles, wavelength shifting (WLS) fibers and a surface reflector on tiles, respectively, in view of obtaining large light yield and uniform response from a tile/fiber system. We decided fiber groove path in a tile, groove cross-sectional shape and groove depth for each tile to get uniform response from a tile/fiber. For the tile/fiber system of the final design, the average light yield was larger than 3.0 photoelectrons per minimum ionizing particle (MIP), the response uniformity in a tile was less than 2.5% and a total cross talk from a tile to the adjacent tiles was less than 2.0%. These results satisfied our requirements.

Ultrasonic temperature measurement and uses in optical spectroscopy and calorimetry

A process and apparatus for the photothermal and/or calorimetric investigation of gaseous, liquid and solid measuring material is based on the detuning of an ultrasonic resonator (1). The latter has an ultrasonic transmitter (2) and an ultrasonic receiver (3), which face one another. The signal from the receiver is analyzed by an analyzer (5) as to its amplitude or phase position which gives, as a result of the temperature dependence of the sonic velocity, information on thermal changes in the ultrasonic resonator designed as a gas cell or calorimeter. The present apparatus makes it possible to detect gases or to calorimetrically investigate the material to be investigated, particularly light-conducting elements (5), such as light fibers.

Liquid rare gas calorimeters with excellent energy resolution

For an improved energy resolution of the liquid rare gas calorimeter, two different experiments are proposed to be made by using a multi-parallel-plate chamber whose electrodes consist of very thin Kapton plates conted with thin copper foils. One experiment is made by using the chamber filled with allene doped liquid argon and another by using the chamber filled with liquid xenon. In the former experiments, the energy resolution is expected to be better than 1% (FWH51) for relativistic heavy ions from Fe to la. In the latter experiments, the energy resolution is expected to be better than 1% (rms) for gamma-rays in the GeV region.

Design and testing of a new isothermal flow gas calorimeter: the Hart Field-deployable natural gas energy meter

The design and testing of a new isothermal flow gas calorimeter is described. The calorimeter achieves complete combustion of the natural gas at temperatures from 400 to 500°C using a bed packed with a proprietary catalyst. The catalyst is 100% efficient for mixtures containing all of the typical natural gas components (C 1-C 6). The calorimeter assembly consists of a flow reactor that is suspended in a high temperature air bath. The temperature sensors for both reactor and shield temperature measurement or control are Pt RTDs. The gas is delivered by a cycling sample loop with constant volume and a lean gas/air mixture is supplied to the reactor. The gas sample net heating value (NHV) is determined from the gas flow rate required to maintain a constant reactor temperature. The water content in the exhaust is measured to obtain the gross heating value (GHV). All operations of the calorimeter including periodic calibration and reporting of heating values, specific gravity, and compressibility data are automated. The calorimeter makes energy measurements with an accuracy of ±1 BTU ft −3 and a precision of 0.5 BTU ft −3 for gas samples having gross heating values ranging from 800 to 1200 BTU ft −3. The calorimeter measures both the net and gross heating values. The mol. percent inerts, specific gravity, and compressibility are calculated by use of empirical correlation equations relating these properties to the net and gross heating values. The gas calorimeter has been packaged for field operation and operation in areas with potentially combustible atmospheres. The field performance of the gas calorimeter is compared with both an on-line gas Chromatograph and a Cutler-Hammer calorimeter.

High voltage control and monitoring system for proportional chambers

A description is given of a system that has been built and operated for distributing high voltage to 2000 channels of proportional chambers in the gas calorimeters of the CDF detector. The system consists of CAMAC-based controllers and distribution modules in the Rabbit hardware standard developed at Fermilab. Current monitoring to 1 nA and remote disconnect are available on each channel. >

The aleph pictorial electromagnetic calorimeter - A high granularity gaseous calorimeter operated in a high magnetic field

We outline briefly the general structure of the Aleph detector, to place in context conceptually and physically the electromagnetic calorimeter. The calorimeter is then described, emphasizing the read-out mechanical and electronic structure, which allows adequate granularity; three layers of towers 3×3 cm 2, approximately 210 000 pieces of analog information. We discuss the basic properties of such apparatus with the results of tests performed on a prototype. We emphasize the peculiarities of operating such a wire gas calorimeter in a strong magnetic field parallel to the wires.

π/e separation with prototype CDF end plug gas calorimeters

Hadron rejection against electron signal of a combined system of electromagnetic and hadron calorimeter has been studied. Data was taken at M4 beam line of Fermilab at energies from 25 GeV to 150 GeV. Hadron rejection of electromagnetic calorimeter is greatly improved by the use of hadron calorimeter information. The details of the results are discussed.