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Showing papers on "Vapours published in 1997"


Journal ArticleDOI
TL;DR: In this paper, it was reported that for the condensaticn of weak binary mixtures on a horizontal tube, where the vapour concentration of ammonia in steam is in the range 0.23 − 0.88 wt, condensation heat transfer is enhanced by as much as 13%.

49 citations


Journal ArticleDOI
TL;DR: In this article, a transferred arc was operated with a current intensity of 90 A, an arc length of 18 mm, and a gas flow rate of. Temperature and relative iron concentration profiles determined experimentally were compared to theoretical values obtained from a two-dimensional model based on mass, momentum, and energy conservation equations and taking into account anode erosion.
Abstract: Spectroscopic measurements have been made on a transferred arc burning in pure argon at atmospheric pressure seeded with iron vapours arising from the anode erosion. The transferred arc was operated with a current intensity of 90 A, an arc length of 18 mm, and a gas flow rate of . Temperature and relative iron concentration profiles determined experimentally were compared to theoretical values obtained from a two-dimensional model based on mass, momentum, and energy conservation equations and taking into account anode erosion. This comparison partially validated the model and showed that the presence of iron vapours, with a relative concentration of about 0.1%, led to a temperature decrease of about 1000 K. Differences between experimental and calculated temperature fields may be due to departures from equilibrium and to uncertainties about the iron vapour concentration and the radiative losses.

34 citations


Journal ArticleDOI
01 Jan 1997-Carbon
TL;DR: In this paper, a semi-implicit finite difference (SDF) scheme was used to predict the adsorption of binary vapour mixtures from air by active carbon beds.

33 citations


Journal ArticleDOI
TL;DR: In this paper, a passive sampling method was developed for acetic acid and formic acid vapours in ambient air, where the vapours were collected in a Palmes diffusion tube and analyzed by ion chromatography.

23 citations


Journal ArticleDOI
TL;DR: In this article, a biofilter was installed to reduce levels of solvent vapours in air exhausted from a rotogravure printing press, which was first humidified and then passed through two filter beds in series which contained a mixture of mushroom compost, activated carbon, lime and polystyrene beads.
Abstract: A biofilter was installed to reduce levels of solvent vapours in air exhausted from a rotogravure printing press. This air was first humidified and then passed through two filter beds in series which contained a mixture of mushroom compost, activated carbon, lime and polystyrene beads. The printing press employed different inks for which the solvents included ethanol, ethyl acetate, n-propyl acetate, acetone, methyl ethyl ketone and toluene. The amount and composition of the solvent vapours in the exhaust air depended on the printing tasks undertaken. Breaks in the supply of solvent to the filter occured during job changeovers and press shut down. The performance of the biofilter under such varying operating conditions was studied. Maintaining moisture in the bed proved critical. Overall solvent removal efficiency was affected by the nature of the solvent mixture, the relative solubility of individual solvents and their relative biodegradabilities. No significant lag period was evident in biofilter performance when sudden changes in solvent vapour composition occurred. It was inferred that the activated carbon's adsorptive properties were at least partly responsible for this. Inferences drawn from observations during plant operation were used to gain insights into the relative importance of various physical, chemical and biological processes.

23 citations



Journal ArticleDOI
TL;DR: In this paper, the MPD method was applied to the adsorption of benzene + 1,2-dichloroethane vapours by a typical active carbon at 293 K. Good agreement was found between the experimental and calculated values of the selectivity of the carbon for benzene, which decreased as the mole fraction of the benzene increased.
Abstract: The new MPD method, described recently, has been applied to the adsorption of benzene +1,2-dichloroethane vapours by a typical active carbon at 293 K. A total of 102 experiments have been carried out for adsorbed mole fractions between 0.06 and 0.94. Good agreement was found between the experimental and calculated values of the selectivity of the carbon for benzene, which decreased as the mole fraction of benzene increased. This variation reflects the heterogeneity of the carbon, which is taken into account by the DR equation. Although the liquid mixture is ideal, deviations from Raoult's law are observed in the adsorbed state, indicating a clear preference for benzene. The values of the activity coefficients obtained from the liquid/solid equilibrium improve the fit of the MPD method.

22 citations


Journal ArticleDOI
TL;DR: In this article, an optode membrane fabricated by immobilizing tetraoctylammonium fluorescein mercuric acetate (TOAFMA), tetra octyl ammonium hydroxide and tributyl phosphate into a polymeric support (ethyl cellulose) was used to detect certain sulphur-containing compounds in the vapours from the hams.
Abstract: The vapours from Spanish dry-cured hams are being sampled by an array of different chemical sensors to assess the quality of the hams during the curing process. Some of the sensors analyse the concentration of sulphur-containing compounds in the vapours, as the presence in higher concentrations of these compounds has been identified as one of the factors indicating the spoilage of hams. The paper describes an optode membrane fabricated by immobilizing tetraoctylammonium fluorescein mercuric acetate (TOAFMA), tetraoctylammonium hydroxide and tributyl phosphate into a polymeric support (ethyl cellulose) to detect certain sulphur-containing compounds in the vapours from the hams. The fluorescence of the TOAFMA is irreversibly quenched by the sulphur-containing compounds in the vapours from the hams. It is observed that over a fixed time interval, the vapour from a bad ham causes a greater fluorescence quenching effect than that from a good ham and the longer the exposure time, the greater is the response of the membranes to the ham vapours. The compound dimethyl disulphide (DMDS) is used to investigate the response characteristics of the optode membranes. A flow rig for producing mixtures with accurately known concentrations of DMDS in nitrogen gas is also described. This system could be easily adapted to work with any volatile liquid.

16 citations


Journal ArticleDOI
TL;DR: In this paper, a piezoelectric quartz crystal detector based on Ag+/cryptand-22/ethylenediamine/NH3/PVC coating with a computer interface for signal processing was prepared for olefin vapours, e.g. alkenes and alkynes.

13 citations


Journal ArticleDOI
TL;DR: In this paper, the separation of hafnium tetrachloride (HfCl4) from zirconium trichloride by preferential reaction with either solid or molten alkali chlorides was investigated in a flowing system.

13 citations


Journal ArticleDOI
TL;DR: In this article, a thin-film piezoelectric acoustic sensor (TFPAS) based on high-frequency piezotransducer chemical gas sensor was developed and studied in detail.
Abstract: A novel, based on thin film high-frequency piezotransducer chemical gas sensor was developed and studied in detail. We call it thin film piezoelectric acoustic sensor (TFPAS). It was found to be sensitive in the ppm level to various hydrocarbon vapours in air. The response of the sensors to the presence of the hydrocarbon vapours tested (propane, pentane, hexane, commercial petrol) was found to be linear within a wide range of the vapour concentrations used. Theoretical model of TFPAS operation as well as potential advantages of the sensor designed are discussed.


Journal ArticleDOI
TL;DR: In this paper, a new method for the detection of some organic vapours was attempted by using the resonant frequency and admittance of quartz crystal for ultra-thin LB films.


Patent
18 Apr 1997
TL;DR: In this paper, the authors describe a cooker with a detachable cartridge with a catalytic coating, made from metal mesh, cellular or porous ceramic, a fabric or non-woven material, or a cellular plastic.
Abstract: The cooker hood consists of a housing (1) situated above the cooking surface, made with an intake (2) for the cooking vapours (3), an outlet (4) and a fan (6) for drawing in the vapours and expelling them through the outlet. The intake contains a detachable cartridge (7) which is permeable to the vapours and consists of a porous material with a catalytic coating. The housing also contains an ultraviolet lamp (8) which is positioned so that its rays intersect the trajectory (10) of the vapours as they pass between the intake and the outlet. The porous cartridge is made from metal mesh, cellular or porous ceramic, a fabric or non-woven material, or a cellular plastic, while the catalytic coating is based on titanium oxide. The UV lamp has a power of 150 W, for example, and is designed to oxidise oily components of the vapours, converting them into water vapour and carbon gas so they can be recycled back into the kitchen without odours.

Proceedings ArticleDOI
20 Oct 1997
TL;DR: In this article, a two-stage analysis is proposed to find general rules for the influence of organic materials on contact reliability: the first step of investigation is to determine the identity and quantity of the gases emanated from interesting organic materials by chemical analysis.
Abstract: The formation of carbon on the contact surfaces of commercial relays by thermal decomposition of organic vapours emanating from various organic materials may cause an undesirable increase of the contact resistance in the range of several Ohms. A two stage analysis is proposed, in order to find general rules for the influence of organic materials on contact reliability: The first step of investigation is to determine the identity and quantity of the gases emanated from interesting organic materials by chemical analysis. The second step is to investigate the influence of individual organic vapours and their combinations on contact reliability, using a specially developed test device. This test equipment exposes model switches to an atmosphere of synthetic air with a trace of one organic vapour. The concentration of this vapour is increased every 25.000 switching cycles in order to determine the so called critical concentration, when the contact resistance increases significantly due to carbonization. Critical concentrations of various organic vapours in combination with three different contact materials were measured. The relationship between these results and specific properties of the gases or their molecules was evaluated. First studies show the correlation between the contact compatibility on the one hand and a few parameters of the vapours or their molecules like volatility, the basic structure type of the molecule (e.g. aromatic or aliphatic, length of the carbon chain), and certain active groups on the other hand.

Patent
16 Jan 1997
TL;DR: In this paper, the cleaned and compressed vapours are taken to the device for contact drying as a heating agent, where the energy consumed inside the operated installation is used more efficiently to dry the sewage sludge and a considerably improved energy balance is thus achieved.
Abstract: In a process for drying sewage sludge or sludges of similar consistency, use is made of a device (13) in which vapours arising during contact drying are taken to at least one compression state. Here, vapours are taken to a higher pressure and impurities are separated therefrom. The cleaned and compressed vapours are taken to the device (13) for contact drying as a heating agent. Thus the energy consumed inside the operated installation is used more efficiently to dry the sewage sludge and a considerably improved energy balance is thus achieved.

Journal ArticleDOI
TL;DR: In this paper, a new system for identification of organic vapours and analysis method of mechanism between organic vapor and sensitive materials were attempted using the resonant resistance and resonant frequency of Quartz Crystal Analyzer (QCA).
Abstract: The new system for identification of organic vapours and analysis method of mechanism between organic vapours and sensitive materials were attempted using the resonant resistance and resonant frequency of Quartz Crystal Analyzer (QCA). The resonant resistance shift means rheological changes in sensitive LB films occurred by the adsorption of organic vapours, while the resonant frequency shift represent the mass of organic vapour loaded in or on the sensitive LB films. Thus we can obtain more accurate response mechanism of organic vapour using the resonant frequency and resonant resistance diagram. The organic vapour response mighit be devided by two type; surface adsorption and penetration into sensitive material. The interface between inner side and surface of sensitive LB films is not clear yet. Organic vapours had different positions in the Frequency-Resistance (F-R) diagram as to the kinds and concentrations. Thus F-R diagram can be applied to the development of one-channel gas sensing system...

Journal ArticleDOI
TL;DR: In this article, the Vickers microhardness test was used to determine the fracture toughness of hot-pressed Si 3 N 4 in vapours of K 2 O and SO 2 from boiling K 2 SO 4, as a function of time.


Patent
29 Apr 1997
TL;DR: In this article, a method for separating crude oil or gaseous condensates into the following fractions: fuel, diesel, light and heavy kerosene, light, medium gasoline as well as liquefied and dry gas.
Abstract: The present invention relates to a method and to equipment for separating crude oil or gaseous condensates into the following fractions: fuel, diesel, light and heavy kerosene, light and medium gasoline as well as liquefied and dry gas. The present method comprises the following steps: (a) separating the vapours preferably after recovery heating at each upper stage; (b) feeding the separated vapours according to different paths for condensation; (c) condensing and fractioning the vapours; and (d) stage-heating and vaporising the crude residues with inter-stage separation of vapours and feeding of the latter into the column. The described equipment comprises the following elements: (e) at least one fractioning condenser and evaporators; and (f) a multistage device for separating the vapours, each stage being provided with a vapour separator; (g) the vapour separators and the top of the column are connected to the fractioning condenser; (h) heating and vaporisation of crude residues is performed at various stages in a kiln, with the vapours being separated between the different stages and further fed into the column.

Patent
18 Nov 1997
TL;DR: A charcoal filter and pressure release apparatus was used with an apparatus for combustion enhancer as disclosed in PCT/SG96/00022 as mentioned in this paper, where the charcoal filter absorbs hydrocarbon gas vapours, and filters air impurities from ambient air preventing contamination and interference with the liquid mixture in the apparatus.
Abstract: A charcoal filter and pressure release apparatus to be used with an apparatus for combustion enhancer as disclosed in PCT/SG96/00022. Hydrocarbon gas vapours vented from the fuel tank and ambient air are mixed with a liquid mixture within the combustion enhancer apparatus, causing dissociation of molecular chains of hydrocarbon gas vapours, then exposed to negatively charged electron ions forming negatively charge pre-oxidised hydrocarbon gas vapours, for mixing with air and fuel in the combustion chamber of an engine. The charcoal filter (307, 311) absorbs hydrocarbon gas vapours, and filters air impurities from ambient air preventing contamination and interference with the liquid mixture in the apparatus for combustion enhancer. Unburnt hydrocarbon gas vapours are absorbed in the charcoal filter members (307, 311) and released by vacuum effect to mix the negatively charged pre-oxidized hydrocarbon gas vapours in the combustion enhancer apparatus, for further combustion.

Patent
15 May 1997
TL;DR: In this article, the authors proposed a self-mixing cell-structure which makes for good selfmixing of the respective flows of gases and vapours, while preventing self mixing in an axial direction.
Abstract: A drying process converts sticky phase sludge (44) with a dry residue of 50 preferably 65 % to a bulk dry granular condition with a dry reside of 80 preferably 90 %. The process comprises: (a) the sludge (44) is continually dried as it passes through the drying section (46) in contra-flow against dried sludge (44) and sludge vapour particles (49) without self-mixing of either the drying sludge or vapours, in the respective direction of flow (33, 50); (b) drying takes place by cross-flow mixing of the vapours and the sludge (44) with reference to the respective direction of flow (33, 50); (c) air is mixed in with the vapours at the end of the drying section (46) or in a subsequent vapour removal section (47), lowering the dry sludge temperature while minimising the water vapour particle pressure, and intensifying the drying process. Further claimed is (d) a continually-operated linear drying assembly (11) whose overall length is great in comparison to its cross-section; and (f) the assembly incorporates rotor (20) heat-transfer ribs (29), creating a cell-structure which makes for good self-mixing of the respective flows of gases and vapours, while preventing self-mixing in an axial direction.

Patent
25 Apr 1997
TL;DR: In this paper, a method for mixing two fluid flows containing differing vapours and/or gases comprises directing the flows together around one or more electrodes (16, 21), and applying a high voltage (V).
Abstract: In a method for mixing two fluid flows containing differing vapours and/or gases comprises directing the flows together around one or more electrodes (16, 21), and applying a high voltage (V). This produces a corona discharge. Also claimed is the corresponding equipment.


Journal ArticleDOI
TL;DR: In this article, a piezoelectric crystal detector was used for monitoring organic compounds in indoor air and in factories, eight gas-liquid chromatography coatings were selected as the coating of the P/Z crystal.
Abstract: To solve the problem of high humidity interfering with the monitoring of organic vapours commonly found in workplace air using the piezoelectric crystal detector, a battery operated fan dryer was incorporated with the P/Z detector to provide a light, sensitive and portable monitor for analysing organic vapours in air. The organic vapour monitor developed is sensitive to analyse organic vapours at ppm levels below the control limits of these vapours. To select a suitable coating for the P/Z crystal detector to be used for diumal monitoring of organic compounds in indoor air and in factories, eight gas-liquid chromatography coatings was chosen for study. Based on their sensitivity, selectivity, bleeding rate and long term stability towards commonly encountered organic vapours such as 1,1,1-trichloroethane, chloroform, benzene and toluene, Apeizon grease L was selected as the coating of the P/Z crystal. The optimised analytical parameters are : temperature 22°C - 43°C, relative humidity 40% -100%, response time 2 - 30 minutes and linear working ranges 88.8ppm - 1880ppm.


Patent
21 Oct 1997
TL;DR: In this paper, a method and device for the detection of vapours of cocaine and associated compounds is described, which involves sampling a volume of air suspected of containing cocaine vapours and passing this air through a filtration system that removes any particulate matter and binds vapours, if present.
Abstract: A method and device for the detection of vapours of cocaine and associated compounds are disclosed. The method involves sampling a volume of air suspected of containing cocaine vapours, passing this air through a filtration system that removes any particulate matter and binds vapours of cocaine and associated compounds, if present, for further analysis. A preferred associated compound-vapour is that of ecgonidine methyl ester. The device is comprised of a sampling, filtration and vacuum port components and can be easily attached to a container, and suction source, for the sampling of air.

Proceedings ArticleDOI
25 May 1997
TL;DR: In this paper, the response mechanism between organic vapours and polymeric sensitive LB films was analyzed using the resonant frequency and resistance method of a quartz crystal microbalance, which can be used to analyze the surface adsorption and penetration into sensitive polymeric LB films.
Abstract: The adsorption and desorption behavior of organic vapours for polymeric sensitive LB film was investigated using the resonant frequency and resistance method of a quartz crystal microbalance. A new method was used to analyze the response mechanism between organic vapours and polymeric sensitive LB films. When the organic vapours were adsorbed into sensitive LB films, the rheological changes in LB films were observed by the quartz microbalance resonant method. To investigate the characteristics of organic vapours, a resonant frequency-resonant resistance (F-R) diagram was used. The quantitative information about organic vapours adsorbed and quantitative change of sensitive LB films can be obtained. In experimental results, the response of organic vapours can be separated into two types; surface adsorption and penetration into sensitive LB films. The response mechanism between organic vapours and sensitive LB films can be obtained from the F-R diagram.