Showing papers on "Vapours published in 2009"

Detecting amine vapours with thermally carbonized porous silicon gas sensor

Abstract: A capacitive type porous silicon based gas sensor for detecting amine vapours has been developed The sensor is highly sensitive, eg, to methylamine and trimethylamine vapours, and its electrical parameters recover totally after exposure to studied gases Thermal carbonization of porous silicon under acetylene atmosphere was carried out to produce stable and attractive surface to amine vapours The sensor response to studied amine vapours can be separated from its response to humidity changes since their electrical responses act reversely In addition to the vapours of methylamine/water and trimethylamine/water solutions, the sensor was also used to detect different amines, which are generated during spoilage of raw shrimps and Baltic herring fillets at room temperature Fourier Transform Infrared spectroscopy was used to detect the amine vapours and other volatile compounds simultaneously with sensor measurements (© 2009 WILEY-VCH Verlag GmbH & Co KGaA, Weinheim)

Process and apparatus for dewatering cellulosic fermentation products

Abstract: A liquid mixture of water and a small percentage of an alcohol, for example a cellulosic fermentation broth, is converted into a mixture of vapours. The vapour mixture includes an increased percentage of alcohol vapour relative to the liquid mixture but is mostly water vapour. Water vapour is removed from the vapour mixture by permeation through a vapour separation membrane unit. Retained vapour has an increased alcohol content, optionally to the level of a fuel grade alcohol. Heat energy in permeate or product vapours or both may be recovered, for example by us as heating steam or by flow through a heat exchanger. The membrane unit may have two or more stages. Permeate from a stage may be condensed and used for example as fermentation make up water, compressed and fed to the permeate from an upstream stage or heating steam, or fed to another membrane stage for further dewatering.

Effect of organic vapour on porous alumina based moisture sensor in dry gases

Abstract: A capacitive porous alumina based trace moisture sensor in the range of 50 to 500 ppm (V)was fabricated by low cost sol-gel technique. The cross-sensitivities due to the presence of organic vapours like ethanol, methanol, acetone and benzene were studied. The change in response and recovery time with ppm for moisture sensing was also calculated. The experimental results conclude that moisture sensor is responsive to the polar organic vapours but has almost negligible response to the nonpolar molecules like benzene. Response of the sensor to the organic vapours as compared to the moisture sensitivity is very less. The effect of ambient temperature was found to be negligible.

Sensorial characteristics of conductive polymers

Abstract: This paper deals with the investigation of intrinsic conductive polymer PEDOT-PSS and development of vapour sensors. These sensors are based on the specific vapours influence on the electrical parameters. The designed sensors consist of glazed ceramic substrate with gold interdigital electrodes covered by a thin layer of conductive polymer. The insulation gap between electrodes was investigated in the range of 50 – 200 µm in order to achieve the maximal sensitivity. Temperature and humidity dependences of PEDOT-PSS layers were measured in the climatic chamber, influence of particular vapours on electrical parameters were measured in the special gas chamber. Except for temperature, humidity and vapour sensitivity, long term stability was also studied.

A study of the gas specificity of porous silicon sensors for organic vapours

Abstract: A porous silicon sensor was investigated as a means to determine the response specificity for organic vapours. Porous silicon layers were fabricated by electrochemical anodization of p-type crystalline silicon in an HF ethanol solution under various conditions. The porous silicon sensors were placed in a gas chamber with various organic vapours, and the changes in electrical resistance under constant voltage of each sensor were used as detection signals. The sensors recorded various changes in resistivity for various organic vapours.

Vapour sensing characteristics of zno-znmn2o4 ceramics using the visual basic-based measurement system

Abstract: In the present paper, ZnMnO 3 ceramics in a disk shape, synthesized by mixed oxide technique, has been investigated for NH 3 , ethyl alcohol, commercial liquor, methanol, H 2 O 2 and acetone vapours. Structural analysis of the ZnMnO 3 ceramics was carried out by X-ray diffraction (XRD). The XRD pattern revealed the nature of the film with a mixed phase comprising of ZnO and ZnMn 2 O 4 . The measurements and processing of the data was made using ADC0809, 74LS244, ET-PCI8255V3 data acquisition card, computer and Visual Basic program. The system is easy to setup and use. A visual basic program is proposed and explained in order to evaluate vapour response property. Results showed that the resistance of this sample at room temperature decreased in the presence of these vapours at 30°C in air atmosphere. The measured sensitivities to some vapours (NH 3 , ethyl alcohol, commercial liquor, methanol, H 2 O 2 and acetone vapours) of this sample were investigated. It is clear that this material is the most sensitive to NH 3 vapour and the least sensitive to acetone vapour. The gas sensitivity largely depends on the kind of test gas species. The sample is sensitive and selective to NH 3 , ethyl alcohol and commercial liquor vapours.

Device for processing solids by applying gases or vapour.

Abstract: The present invention refers to the design of a device for processing solids by applying air, gases or vapours, which is operated as a source bed and has novel geometric characteristics. The invention is useful for processes involving the contact of air, gases or vapours with solids, in operations involving the transference of heat, mass and chemical reactions. The purpose of the present invention is to have a device which brings air/gas/vapour into contact with solids, which is efficient and different from those currently available on the market since the inner construction thereof is novel and presents the following advantages: an efficient solid-fluid contact, without death zones (zones with no contact), with a substantial agitation of the solids which improves the transference of heat, mass and chemical reactions; the contact operation is performed at low pressures; the charge and discharge of solids is easily performed without disassembling the equipment; an easiness of scaling i s provided, and finally the fluid control of solids within the system is performed by a valve.

Performances and Deactivation of Supported Precious Metal Catalysts in the Oxidation of an Engine Oil Vapour

Abstract: In this paper, a homemade apparatus was built in order to study the formation of carbonaceous deposits on stainless steel, in order to model the fouling by oil vapours of gas/water heat exchanger used in energy production systems fed with natural gas. Oil vapours were shown to form, at the surface of stainless steel, a varnish layer very difficult to remove, as shown by TPD. One solution to this fouling was shown to be the oxidation of oil vapours by a catalytic system. Pt/alumina and to a lower extend Pd/ceria-alumina catalysts exhibited interesting performances, but we demonstrated that they can be deactivated by the oil vapours, which form a carbonaceous deposit (coke) at their surface. Nevertheless, Pt/alumina can be regenerated by increasing the oxygen amount up to 20 vol% or so during a limited duration and at moderate temperature (450 °C). In order to take benefit of such a regenerative process, it was vital to use non degraded oils, because vapours originating from an aged oil (treated at 300 °C in air) were not likely to be much oxidised to CO2 and H2O and therefore coke formed at catalyst’s surface under these conditions cannot be removed by the regenerative treatment under oxygen excess.

Apparatus and method for drying biodiesel

Abstract: The present invention refers to an apparatus and a method for the removal from biodiesel of excess water resulting from hygroscopic absorption during transport or storage. The apparatus is compact, can be transported on a mobile base and can be connected directly to a warehouse for decontamination of the extracted water by means of decanting or recycling. The apparatus for drying biodiesel comprises: - a device (2) for extraction of the biodiesel from a warehouse (1); - an evaporation circuit comprising a return pipe (3), heat exchangers (3c and 3e) and a flash reactor (4); - a condenser (5) to condense waste vapours; - a collector for the waste vapours (6) condensed in the condenser (5); and - a centrifugal pump (5c) for elimination of the waste vapours.

Device of carbon nanotubes growth by method of ethanol pyrolysis

Abstract: FIELD: chemistry. ^ SUBSTANCE: invention relates to devices for carbon nanotubes production. Device contains reaction furnace with unit for supplying and introducing of ethanol vapours, holder of padding with padding, which has catalytic surface, and heating element. Inside of reaction furnace placed is reaction chamber, which contains separable part, joint with drive of axial movement. Unit of ethanol vapours supply contains evaporating cell with ethanol, joint with ethanol vapours input. Heating element is placed inside reaction chamber in padding zone. Device is supplied with generator of particle flow, placed in reaction chamber, and made in form of at least one conductive net, connected to source of alternating or/and source of continued voltage. At least one conductive net is made of catalytic material. Reaction chamber is made of quartz ceramics. In evaporating cell heater and ethanol temperature measuring instrument are placed. Inlet of ethanol vapours is made of conductive material, and is connected to source of alternating or/and source of continued voltage. Inlet of ethanol vapours is made in form of two pipes, which are coaxially placed one in the other with ability to move relative each other. ^ EFFECT: increasing nanotubes quality and device reliability. ^ 6 cl, 1 dwg

Carbon Deposit Formation in Normal-Pressure Electrical Discharges in Hydrocarbons

Abstract: The process of synthesis of carbon deposits from hydrocarbon vapours in low-current electrical-discharge plasma was investigated in the paper. The carbon deposits were effectively synthesised in discharge of positive polarity generated between a stainless steel needle and a plate made of nickel alloy, for the discharge current ranged from 0.1 mA up to 3 mA. The experiments were carried out at normal pressure in cyclohexane vapours with argon as carrier gas. The process of synthesis of carbon deposits was investigated using optical emission spectroscopy.

Characterization and evaluation on the potential of activated carbon derived from durian shell for adsorption of toxic vapours

Abstract: Every day, large quantities of volatile organic compounds (VOCs) are emitted into the atmosphere from anthropogenic and natural sources. VOCs are organic chemical compounds that have high enough vapor pressures under normal conditions to significantly vaporize and enter the atmosphere. Toluene is a mono aromatic organic compound which categorized in the family of VOCs. The common name for toluene is methylbenzene which is widely used as an industrial feedstock and as a solvent. Single short term exposure of toluene can caused eyes and respiratory tract irritations while long-term exposure can lead to damages of neurological and reproductive system.

Method for steam cracking of oil refined products

Abstract: The invention relates to oil refining, in particular to a method for steam cracking of oil refined products, and can be used for the targeted processing of atmospheric vacuum distillation products and cracked products. The aim of the invention is to increase the yield of light diesel fraction of 160-360°C by converting the vapours of heavy petroleum products 340KK in lighter diesel fractions and to produce only the diesel fraction as a base commercial product. The inventive method for steam cracking of oil refined products involves heating feed stock vapours, wherein diesel-oil fractions or vacuum gasoils are used as a feed stock and the feed stock vapours are electrochemically heated by electric current at an excess pressure of 0.01-0.5MPa, a temperature of 300-450°C and in the presence of Al, Cr, Ni and Fe metal alloys which are used in the form of individual conductors situated in a vapour cracking area in contact with the flowing feed stock vapours, through which an electric current of 0.1-10 kV and 1-1·104 amperes passes.