The article deals with the solution to the increased level of environmental pollution by emissions of solid particles from small sources. The research aimed to build an efficient electrostatic ...precipitator directly in the combustion device, ensuring simple maintenance and low space requirements. During the measurements on the experimental equipment, the average production of particulate matter was measured with and without the use of an electrostatic precipitator. Three combustion modes were used during the measurements: minimum, optimal and maximum performance. The results of the measurements showed up to 52.3 % efficiency in removing particles from flue gases.
Display omitted
•Electrostatic precipitator used for a small heat source.•Using space in the heat exchanger of the heat source for the construction of an electrostatic precipitator.•Effectivity of electrostatic precipitator during minimum, optimal and maximum performance.•Possibility of capturing up to 52.3 % of particles from flue gases.
•Protection of mild steel in 1M HCl by PCs.•EIS plots showed the adsorptive mechanism of corrosion inhibition.•Polarization results indicate that all studied compounds are mixed-type inhibitors but ...predominantly cathodic.•The SEM and EDX showed the existence of protective film of PCs on metal surface.•Quantum chemical study provide good support to experimental results.
The adsorption and corrosion inhibition effect of three pyridine derivatives namely 2-amino-6-methoxy-4-(4-methoxylphenyl) pyridine-3,5-dicarbonitrile (PC-1), 2-amino-6-methoxy-4-(4-methylphenyl) pyridine-3,5-dicarbonitrile (PC-2) and 2-amino-6-methoxy-4-phenylpyridine-3,5-dicarbonitrile (PC-3) on mild steel in 1M HCl was investigated using gravimetric, electrochemical impedance spectroscopy, potentiodynamic polarization techniques and quantum chemical study. PCs are mixed-type inhibitor mainly cathodic. Activation energy (Ea), equilibrium constant (Kads), free energy of adsorption (ΔG°ads) were calculated and discussed. The studied inhibitors (PCs) obeyed Langmuir's adsorption isotherm. Protective film of PCs on mild steel surface was investigated by using SEM and EDX. Quantum chemical parameters were carried out in the framework of the density functional theory (DFT).
•We have carried out a dynamic study of adsorbers.•Activity performed by new gravimetric version of the Large Temperature Jump method.•The kinetics measurements have been carried out under real ...operating conditions.•Results can support the design of adsorbers for adsorption cooling systems.
This paper presents a new experimental setup devoted to measure the ad-/desorption kinetics of an Ad-HEX (adsorbent+heat exchanger) under typical boundary conditions of an Adsorption Heat Transformer (AHT) as well as the results of the first test campaign carried out. The experimental apparatus can be considered as a gravimetric version of the known Large Temperature Jump method. In fact, the dynamic evolution of the uptake during the isobaric ad-/desorption stages is directly measured by a weighing system suitable to work in the range of 5–600g of sample mass (adsorbent+HEX) with the accuracy ±0.1g and the time response shorter than 0.1s The experimental campaign was conducted on an Ad-HEX composed of granules of a commercial SAPO-34 adsorbent placed on a flat type aluminum HEX, under operating conditions reproducing two different thermodynamic cycles (Th=90°C, Te=10°C, Tc=30 and 35°C), typical for adsorption air conditioning.
The influence of the grain size (ranging from 0.350 to 2.5mm) on the adsorption dynamics both in monolayer and multilayer configurations at variable and constant “heat transfer surface/adsorbent mass” ratios (S/m) was studied. The results showed that, for the Ad-HEX configurations tested, the adsorption dynamics can be properly described by a modified Linear Driving Force approach by the use of a single temperature-invariant characteristic time τ. The invariance of the specific cooling power was revealed when the S/m ratio was kept constant (S/m=1.23m2/kg). This ratio is found to be a useful parameter for both assessment of the dynamic perfection and optimization of various Ad-HEX configurations.
Using gravimetric and electrochemical research methods, the corrosion-electrochemical behavior of carbon steel grade St3 in Kura river water has been. Gravimetric measurements were carried out under ...operating conditions of the Shemkir and Yenikend hydroelectric power stations for one year. Along with this, the ionic and bacteriological composition, as well as some physicochemical parameters of these waters were established. It revealed that St3 in the Kura water corrodes at a rate of (0.04÷0.05) g/m2•hour, which is characteristic of steel corrosion in fresh waters. In the atmosphere of hydraulic structures, steel corrodes at rather a low rate, i.e. (5÷6)10-3 g/m2 hour. As a result of biochemical analysis, sulfate-reducing bacteria (SRB) were discovered in these waters, which are a dangerous organism that releases the corrosive substance of H2S. By taking the anodic and cathodic polarization curves, a quasi-stationary steel corrosion rate was established to be 0.06g/m2 h.
The availability of commercial gravimetric and volumetric systems for the measurement of adsorption equilibrium has seen also a growth of the use of these instruments to measure adsorption kinetics. ...A review of publications from the past 20 years has been used to assess common practice in 180 cases. There are worrying trends observed, such as lack of information on the actual conditions used in the experiment and the fact that the analysis of the data is often based on models that do not apply to the experimental systems used. To provide guidance to users of these techniques this contribution is divided into two parts: a discussion of the appropriate models to describe diffusion in porous materials is presented for different gravimetric and volumetric systems, followed by a structured discussion of the main trends in common practice uncovered reviewing a large number of recent publications. We conclude with recommendations for best practice to avoid incorrect interpretation of these experiments.
Inhibition effect of three bis-Schiff bases of isatin namely (2-methoxybenzylidene) hydrazono) indolin-2-one (HZ-1), (2-hydroxybenzylidene) hydrazono) indolin-2-one (HZ-2) and (4-nitrobenzylidene) ...hydrazono) indolin-2-one (HZ-3) was studied on mild steel corrosion in 1.0 M HCl by gravimetric measurements, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and quantum chemical study. The values of activation energy (E sub(a)), equilibrium constant (K sub(ads)), free energy of adsorption Delta G degree sub(ads), activation enthalpy Delta H super(*) and activation entropy Delta S super(*)were discussed. The adsorption of inhibitors on metal followed Langmuir's adsorption isotherm. SEM and EDX observations confirmed the existence of protective inhibitor film on metal surface. Quantum chemical study supports the comparative inhibition effect of HZs.
In this paper, a synthesized organic compound from the family of ketene dithioacetal was studied as corrosion inhibitor for mild steel in 1.0 M hydrochloric acid by gravimetric measurements. The aim ...of this work is to study the effect of inhibitor concentration and temperature on the corrosion resistance, and to compare the experimental results with those obtained by mathematical models. The structural properties are characterized using the scanning electron microscopy technique. It has been found that the inhibition efficiency increases with increasing inhibitor concentration. The adsorption of studied compound on mild steel surface follows Langmuir’s isotherm. Taking into account the influence of inhibitor concentration and temperature on the corrosion inhibition efficiency, obtained data were analyzed by two mathematical models based on linear and quadratic regression. The obtained experimental results are in a good agreement with those predicted by the quadratic regression models.
Missions finalized at measuring the space-time variations of the Earth gravity field have become of high relevance in recent years. These missions are indeed of interest for scientific purposes and ...applications in several fields. Precise observations of the Earth gravity field can be accomplished by measuring the distance between two satellites flying in suitable orbits. Several mission concepts foresee an active formation control to maintain the distance variations between the two satellites within given bounds. In this paper, we first present an original constellation model, called the Triangle Dynamics (TD) model, which is particularly suitable to describe the orbital dynamics of satellite pairs. Open-loop simulations are performed, where the TD model is compared with a standard model, derived from the well-known Hill–Clohessy–Wiltshire (HCW) equations. The simulation results show that the TD model provides more accurate predictions than the HCW model. Then, we propose a formation control approach based on a new Model Predictive Control (MPC) algorithm. The core of this algorithm is the TD model, which is used in real-time to predict the behavior of the satellite pair, allowing the computation of an optimal formation control command. A case study concerned with the Next Generation Gravity Mission (NGGM) is presented to demonstrate the effectiveness of the proposed MPC-TD algorithm.
Martensitic stainless steels are difficult-to-cut materials, so the utilization of the cutting fluids with high flow rates is considered necessary in their machining. However, flood cooling method ...represents a high risk to human health and environment and is also a great economic burden. A chilled jet of compressed air is one of the possible alternatives to conventional liquid coolants. As corrosion can occur even in dry machining, the aim of this paper was to investigate the feasibility of replacing conventional emulsion coolant with the chilled air out of Ranque-Hilsch counter-flow vortex tube. An important outcome of corrosion testing showed a beneficial effect of the chilled air-cooling method on the corrosion resistance since it is on increase over a prolonged time. As expected, the feed rate f was confirmed to be the most important factor affecting the Ra, but the most interesting finding was that about non-significant influence of the cooling method on reducing the Ra and consequently on increasing the corrosion resistance of machined surface. Therefore, the chilled air-cooling by a vortex tube can be successfully applied to turning of steel X20Cr13, thereby eliminating the ecological load caused by the application of conventional liquid coolant.
PDF
