Showing papers on "Vapours published in 2019"

Fully Inkjet-Printed CuO Sensor on Flexible Polymer Substrate for Alcohol Vapours and Humidity Sensing at Room Temperature

Abstract: This work focuses on an inkjet-fabricated sensor based on copper oxide nanostructured particles on polymer flexible substrate for the sensing of alcohol vapours and humidity at room temperature. Nanoparticles were prepared by a microwave-assisted solvothermal sealed vessel synthesis method. The ink composition was developed on the basis of viscosity and surface tension optimization by the addition of polymeric steric surfactant and dispersant. The printing process was optimized with the help of non-dimensional criteria. Silver nanoink was used for the printing of an interdigitated pattern on a PET substrate which was overprinted by the copper oxide ink, thus obtaining a flexible flat sensor. Material design and all fabrication steps of the sensor respected the temperature limitation given by the thermal stability of the polymer substrate. Printed layers and motifs were characterized microscopically and by resistance measurement. The effectiveness of the prepared sensor was demonstrated and studied by measuring the response to saturated vapours at room temperature. The sensing layer showed the opposite resistance response to stimuli than expected for the well-known p-type sensing mechanism of CuO sensors operated at high temperatures. In addition to vapour sorption, condensation and desorption influencing electron, proton and ionic conductivity, manifestation of another mechanism was observed and an explanation suggested in terms of the electrochemical mechanism.

Evaluation of HZSM-5 Zeolite as Cracking Catalyst for Upgrading the Vapours Generated in the Pyrolysis of an Epoxy-Carbon Fibre Waste Composite

Abstract: In this paper the performance of HZSM-5 zeolite in the thermo-catalytic treatment of the vapours and gases evolved from the pyrolysis of a carbon fibre-epoxy waste composite has been evaluated. The experiments have been carried out in a laboratory-scale installation consisting in a 3.5 L tank reactor, where pyrolysis of the waste happens, and a 0.5 m long tubular reactor placed in series, where the thermo-catalytic treatment of the gases and vapours coming from the tank reactor takes place. The catalytic activity of the zeolite has been studied at 700 and 900 °C, in two different placement configurations and in presence and absence of carrier gas. HZSM-5 zeolite is capable of cracking the organic compounds of the liquid phase, generating a liquid fraction with high proportion of water. In the presence of carrier gas, this catalyst also increases the proportion of H2 in gases. In general terms the effect of the catalyst is not very noteworthy, probably due to the large molecules that are involved in the process and due to problems of poisoning and deactivation with coke, sulphur and nitrogen compounds. In any case, it has been demonstrated that it is possible to produce a gas fraction with more than 50 vol.% of H2 in all experiments in which the treatment of gases and vapours is applied.

Estimating the Service Life of Activated Carbon Filters for Air Purification

Abstract: It is very important to be able to predict the breakthrough time of gas mask filters under real life circumstances. This article describes the use of a very simple predictive equation, the Wheeler-Jonas equation, that yields excellent predictions but only within a very restrictive set of boundary conditions. In order to make this model work in a more realistic environment, it has been gradually adapted to take into account a number of parameters related to this environment: a non-constant inlet concentration, a breather flow, new physical forms of activated carbon, the relative humidity and temperature of the ambient air, chemisorbed gases and mixtures of organic vapours. As (nearly) all of these parameters can be calculated independently of each other, based on data that are either readily available or that can be measured, their influence on the complexity of the model stays low. This makes this combined model both easy to use and powerful in predicting breakthrough times of gas mask filters under real-life conditions.

Combined Heat and Mass Transfer during Condensation of Vapours Mixture and Non-Condensable Gas in a Vertical Tube

Abstract: The problem of laminar film condensation from binary vapours mixture with the presence of non-condensable gas (air) flowing in a vertical tube is numerically investigated. The set of the non-linear parabolic equations expressing the mass conservation, momentum, energy, and species diffusion in both phases with the boundary conditions are resolved by using a finite difference numerical scheme. A comparative study between the results obtained for three cases (water-ethanol-air, water-methanol-air, and ethanol-methanol-air) under the same conditions is made. The impact of varying the wall temperature, the inlet vapour mass fractions, and the inlet liquid mass flow rate on the conjugate the heat and mass transfer during the condensation of the studied mixtures are examined. It is found that the condensation of water-methanol-air corresponds to a higher latent heat flux QL2 and accumulated condensation rate Mr2 when compared with water-ethanol-air and ethanolmethanol-air. Moreover, the nature of the fluid plays an important role in the heat and mass exchanges.

Gas-Dynamic Kinetics of Vapour Sampling in the Detection of Explosives.

Abstract: The dynamic sorption concentration of explosive vapours on concentrators made of a metal mesh, and the transportation of explosive vapours through the extended metal channels are considered. The efficiency of the concentration and transportation is determined by the breakthrough of the substance’s molecules through the channels. The research methods we used were breakthrough calculation theory and experiment. When calculating the breakthrough, a mesh was presented as a set of parallel identical channels. Wire mesh and extended channels were made of stainless steel. The breakthrough is determined through the specific frequency of the collisions between the molecules and the channel’s surface. This is presented as a function of the ratio of the substance diffusion flow to the channel’s surface to the airflow through the channel. The conditions for high-speed concentration, complete capture of explosive vapours, and low vapour losses during their transportation through the extended channels were determined theoretically and experimentally. For a concentrator made of a mesh, the condition of a high concentration rate at a high breakthrough (up to 80%) was determined. The described sorption concentration is used in portable gas chromatographic detectors of explosive vapours of the EKHO series.

Vapour recovery system during oil products reception and storage at oil storage tanks

Abstract: FIELD: oil industry.SUBSTANCE: system for catching vapours when receiving and storing oil products at petroleum storage depots relates to devices for trapping oil vapours and can be used in oil industry. Invention includes separate tank for collection of vapours, main steam line with sections, refrigerating unit, compressor, relays, manometers, check valves with different opening pressure, buried reservoir, electric motor, shaft with centrifugal wheels. At the same time the buried reservoir has two sections and is partially filled in one section with low-octane component, and in the other - with gasoline A-76. Technical result is achieved by pumping of vapours by compressor, from "big" breaths into separate reservoir for collection of vapours with subsequent supply through check valve of high pressure of vapours into section of reservoir with low-octane component, which is equipped with shaft with centrifugal wheels and cooling element. At that, compressor, refrigerating unit, electric motor for shaft rotation and gate valve are switched off periodically by means of appropriate manometers and relays. Vapours from "small" breaths enter the second section of reservoir with gasoline A-76 and turn into liquid due to temperature reduction in underground reservoir.EFFECT: mixture of light fractions of petroleum products with benzene A-76 can be used for addition of commercial grade gasoline normal-80 and A-76.4 cl, 2 dwg

Method of producing sorbent for acid gas absorption

Abstract: FIELD: chemistry.SUBSTANCE: invention relates to production of an absorber having high adsorption capacity on nitrogen oxides in the presence of organic vapours. Proposed method comprises preparation of impregnating solution, impregnation of porous carrier, curing and thermal treatment. Porous base used is active aluminium oxide with total pore volume of 0.4–0.8 cm/g, impregnating solution contains potassium permanganate, impregnation is carried out at ratio of porous carrier taken in kg to solution in dm, equal to 1:(0.6–0.8). Formation is carried out for 30–60 minutes. Heat treatment is carried out at temperature of 50–60 °C with holding for 2–3 hours, and then continuing heat treatment at 95–105 °C for 1–2 hours.EFFECT: method enables to obtain a nitrogen oxide absorber having dynamic presence in the presence of organic vapours (such as benzene) 1,5–3,3 times greater than known types of absorbers.1 cl, 3 ex

Method (embodiments) and system for blowing coal filter for fuel vapours

Abstract: FIELD: internal combustion engines.SUBSTANCE: disclosed are methods and systems for blowing coal filter for fuel vapours. In one example, when the supercharged engine is in operation, the method may include controlled use of compressed air from the engine inlet port for blowing fuel vapours accumulated in the coal filter. Further, in the absence of supercharging for blowing of the carbon filter, air from the inlet channel can be controlled. Swirled fuel vapours and sucked-in air can be fed into zone upstream of compressor at operation with supercharging or into intake manifold at operation without supercharging.EFFECT: invention can be used in the internal combustion engines.20 cl, 10 dwg

Process layout of a plant for the dehydrogenation of C3-C5 paraffin hydrocarbons (variants)

Abstract: The invention relates to two variants of a plant for producing olefinic hydrocarbons by dehydrogenation of С3-С5 paraffin hydrocarbons in a fluidized bed of a finely divided chromia-alumina catalyst circulating in a reactor-regenerator system comprising: a unit (3) for preparing a feedstock by mixing fresh and recirculated streams of paraffin hydrocarbons in liquid form; a feedstock evaporator (4) and a feedstock vapour heater (heat exchanger for heating), which are heated by steam; a vertical shell-and-tube heat exchanger (6) installed on a dehydrogenation contact gas pipeline (5) and serving to heat the feedstock vapours using the heat of the contact gas as the feedstock vapours to be heated are fed into the shell side of the heat exchanger (6) in counterflow to the contact gas fed into the tube side; and further comprising a furnace (9) for superheating the feedstock vapours before same are fed into a reactor (10) for dehydrogenation. One of the variants of the plant is characterized in that the contact gas pipeline (5) has an additional shell-and-tube heat exchanger (7) installed thereon, forming a system that consists of two stages for heating feedstock vapours when feedstock vapours are fed into the shell side of the heat exchangers (6, 7) successively. The plant is also equipped with a pipeline (8) connected to the shell of the heat exchanger (7) of the second high-temperature stage for heating feedstock vapours and serving to feed a portion of the feedstock in liquid form into the shell side of the heat exchanger (7). The technical result of the claimed invention is an increase in the productivity of plants for the dehydrogenation of С3-С5 hydrocarbons and a decrease in running costs.