Showing papers on "Vapours published in 2008"

Influence of metallic vapours on the properties of air thermal plasmas

Abstract: This paper deals with properties of air thermal plasmas containing vapours of iron, silver or copper. The plasma is supposed to be in local thermodynamic equilibrium, for temperatures ranging from 2000 to 30 000 K. First, the equilibrium composition and thermodynamic properties are presented. Then, the radiative properties are calculated using the method of the net emission coefficient. Finally, the viscosity, electrical and thermal conductivities are calculated using the method of Chapman–Enskog. For all mixtures, mole fractions have been used. The results are computed for various values of pressure, plasma size and proportions of vapours. The influence of metallic vapour is important on the electrical conductivity and on the radiation, even at low concentration. All the metallic vapours present a similar behaviour except iron, which has a stronger radiation emission than the other components.

Quartz crystal microbalance sensor coated with polyaniline emeraldine base for determination of chlorinated aliphatic hydrocarbons

Abstract: A quartz crystal microbalance (QCM) sensor coated with a thin film of polyaniline emeraldine base (EB) was used as a sensitive method for the determination of a number of aliphatic chlorinated hydrocarbons such as carbon tetrachloride, chloroform, dichloromethane, 1,2-dichloroethane vapours. The detection was based on the absorption of the vapours of these organic compounds into the EB film. The frequency shifts due to the absorption of the chlorinated hydrocarbons were measured and calibration curves were plotted. The detection of these vapours can be obtained in part per million (ppm). The work includes also the use of a polyaniline emeraldine salt (ES) film instead of the EB film. It is concluded that the EB film has higher sensitivity towards the organic vapours than the ES film, which can be attributed to the presence of unprotonated amine and imine groups along the polyaniline (PANI) chains in the EB form.

Process for recovering aroma from tea

Abstract: Disclosed is a process for recovering volatile aroma compounds from a tea material. The process comprises the steps of: generating aroma-laden vapours at a pressure of from 0.5 to 1.4 bar absolute from the tea material contacted with water or water vapours,and then condensing the aroma-laden vapours to recover aroma condensate. The process is controlled such that the mass of aroma condensate generated per unit dry mass of tea material is greater than 2 and the aroma-laden vapours comprise no more than 1% by weightentrained liquid.

Method of, and apparatus for, flavour recovery in beer brewing

Abstract: The invention relates to a beer-brewing method, wherein vapours escaping from the wort during a boiling phase are passed, on the steam side, to a rectifying column connected to a wort boiler and the vapours are rectified, at least one flavour-containing distillate being recovered from the vapours and being fed to the wort following the boiling phase. The invention also relates to an apparatus for implementing the method according to the invention.

Detection and discrimination of alcohol vapours using single-step anodised nanoporous alumina sensors

Abstract: The electrical response of single-step anodised alumina sensors to alcohol vapours containing one to four carbon atoms has been studied. In this investigation, the real and imaginary impedance components have been measured in response to the equilibrium saturation vapour pressure of methanol, ethanol, butanol and two structural isomers of propanol. The response to each type of alcohol produces characteristic impedance spectra that allow discrimination and possible recognition of each alcohol.

Study of cross- sensitivity of porous alumina based trace moisture sensor in dry gases

Abstract: Present work deals with the development of capacitive porous alumina based trace moisture sensor in the range of 50 to 500 ppm(V) fabricated by low cost sol-gel technique. For its commercial usefulness, the cross-sensitivities due to the presence of organic vapours like ethanol, methanol, acetone and benzene are studied. The effects of ambient temperature have also been studied. Experimental results show that moisture sensor is responsive to the polar organic vapours but has almost negligible response to the nonpolar molecules like benzene. However compared to the moisture sensitivity, the sensor response to the organic vapours is very small.

Method of collecting components formed during fermentation of must or berry juice

Abstract: FIELD: chemistry. ^ SUBSTANCE: in the period of rapid fermentation of must or berry juice, the components formed in the process are collected. The first portions of the vapours are let through a fine pored glass filter at pressure of up to 2 atm, thereby converting into fine dispersed droplets (mist). Carbon dioxide is then passed through, which is capable of enriching the condensate of the collected components due to a more complete collection of highly volatile components of the berry aroma using carbon dioxide. The vapours then undergo fractional condensation in a condenser - cooler and carbon dioxide is separated with subsequent collection of the vapours. In the condensation process, the vapours are cooled to temperature of minus 3°C and the condensate of native is collected. At minus 10°C ethyl alcohol is collected, while at minus 15°C highly volatile aromatic compounds are collected. This allows for more complete collection of the required components, formed in the fermentation process, and using them in the production of various beverages, as well as for obtaining wines of different qualities. ^ EFFECT: fermentation process can be carried out in containers of any configurations and different volumes without regulation of temperature under conditions providing for taking the released carbon dioxide to the collector of the condenser. ^ 3 ex

Method of sorption and desorption of organic compound vapours with sorbent affected by electromagnetic emission

Abstract: FIELD: physics. ^ SUBSTANCE: invention describes a method of sorption and desorption of organic compound vapours with a sorbent affected by electromagnetic emission, where the sorbent is a fullerene-containing material, and at the sorption stage visible light of 400-600 nm wavelength or ultraviolet of 300-400 nm wavelength is used. Desorption is conducted under the influence of infrared light with wavelength of 610-700 nm, or by cutting emission off. ^ EFFECT: streamlining of the process, improved efficiency. ^ 6 cl, 4 tbl, 3 ex, 2 dwg

A method of managing ammonia vapour

Abstract: A method of managing vapours generated from an ammonia-containing reductant delivery system for an engine of a vehicle is disclosed. During at least a portion of engine-off conditions the method is operable to store ammonia containing vapours generated in the reductant delivery system 73 and, after said storing and during at least a portion of engine operation, the method is operable to purge said stored ammonia into an exhaust 71 of the engine to react in an SCR catalyst in the exhaust flow. The ammonia containing vapours may be stored 230 by a sorbent, a catalyst sorbent including a zeolite, or a charcoal canister. The ammonia containing vapours may be generated in a tank 220 storing liquid reductant e.g. urea.

Adsorption of Binary Mixtures of Organic (n-C6H12 or C6H5Cl) and Water Vapours on Activated Carbon U-03 at 293 K

Abstract: The adsorption of vapour and liquid mixtures of H 2 O + c-C 6 H 12 and H 2 O + C 6 H 5 Cl on activated carbon U-03 has been examined at room temperature 293 K. A model of Independent Co-adsorption proposed by Stoeckli et al. [1,2] leads to a good correlation between experimental and calculated mole fractions for each vapour in binary mixtures. This model can improve predicting dynamic systems such as breakthrough curves and PSA (Pressure Swing Adsorption). This model shows Independent Co-adsorption which can describe static or dynamic systems including breakthrough curves and PSA systems of binary immiscible vapour mixtures adsorbed by a typical industrial activated carbon U-03. The model assumes that vapours are adsorbed according to their respective Dubinin-Astakhov isotherms. A good mutual agreement was found between the calculated and experimental data.

Binary Mixtures of Chlorobenzene and Cyclohexane Vapours Adsorbed under Dynamic and Static Conditions by Activated Carbon Beds

Abstract: The adsorption of mixtures of chlorobenzene (C6H5Cl) + cyclohexane (c-C6H12) onto activated carbon U-03 has been examined at about room temperature. As shown by Stoeckli et al. (2002), combination of the Myers-Prausnitz-Dubinin theory (MPD) with the activity coefficients of the corresponding solid-liquid equilibrium led to a good correlation between the calculated and experimental mole fractions for the adsorption of binary mixture vapours by microporous solids under static conditions. The present study demonstrates the approach, which is based on an ideal adsorbed state (IAS).This can be employed for binary vapour mixtures such as chlorobenzene + cyclohexane under dynamic conditions in PSA (Pressure Swing Adsorption) and dynamic breakthrough experiments.

Biofiltration of Tce Vapours in a Mixed Compost-inert Carrier Trickle Bed

Abstract: Trichloroethylene (TCE) is a common air pollutant particularly stiff to be biodegraded. TCE removal has been here exploited using a pilot-scale biotrickling filter in countercurrent conditions filled with a mixed compost-inert carrier bed. Bioreactor operated for about five months obtaining a maximum elimination capacity of about 5.6 g/(m3h) and a removal efficiency between 50 and 85%. Pressure drop and pH inside the bed remained constant and did not affect bioreactor performance during the whole experiment. Using both organic and inert carrier likely reduced the compaction of the bed and limited the pH drop inside the reactor. Data of elimination capacity were fitted using an original Ottengraf-modified model for steady state conditions.