scholarly journals Optimization of Working Conditions for Perovskite-Based Gas Sensor Devices by Multiregression Analysis

2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Fabio Zaza ◽  
Vanessa Pallozzi ◽  
Emanuele Serra
Keyword(s):  
Carbon Monoxide ◽  
Mathematical Models ◽  
Gas Sensor ◽  
Flow Rate ◽  
Gas Flow ◽  
Resource Depletion ◽  
Productive Efficiency ◽  
Operating Conditions ◽  
Gas Flow Rate ◽  
Sensor Devices

Environmental degradation and resource depletion drive scientific research priorities to develop technologies for sustainable productive systems. Among them, chemical sensing technology plays a key role for regulating energetic, ecological, and productive efficiency by monitoring and controlling the industrial processes. Semiconducting metal oxide sensors are particularly attractive technology because of their simplicity in function, small size, and projected low cost. The aim of this work is to synthesize Ti-substituted lanthanum ferrite perovskite, LaFe0.8Ti0.2O3, in order to develop a resistive sensor device for monitoring carbon monoxide. Since sensor performances are affected by experimental factors, such as temperature, target gas concentration, and gas flow rate, the aim of the authors was to define the optimum working condition by performing multiple regression analyses. The investigated ranges of operating conditions were temperature from 300 to 480°C, carbon monoxide concentration from 100 to 200 ppm, and inlet-gas flow rate from 40 to 100 cm3/min. The results confirm that the applied systematic analysis is a powerful method for studying the direct and indirect effects of every experimental factor on sensor performance and for computing mathematical models with predictive ability, that are useful tools for defining the optimum chemiresistors’ operating conditions. In addition, mathematical models are able to be used as multiple-factor surface calibration for restive gas sensor devices.

scholarly journals Research of the Influence of Temperature Factor on Express Control of Natural Gas Combustion Heat

2020 ◽  
pp. 44-50
Author(s):  
O. E. Seredyuk ◽  
N. M. Malisevich
Keyword(s):  
Natural Gas ◽  
Temperature Measurement ◽  
Flow Rate ◽  
Gas Flow ◽  
Flame Temperature ◽  
Operating Conditions ◽  
Gas Flow Rate ◽  
Combustion Heat ◽  
Gas Combustion ◽  
Functional Scheme

The article is devoted to the study of the influence of the qualitative and quantitative composition of gas environments on the flame temperature of the combusted gas at different values of gas flow rate and changes volume ratio gas-air in its combustion. The functional scheme of the developed labo­ratory stand (Fig. 1), which provides temperature measurement during combustion of natural gas or propane-butane mixture, is considered. The design of the developed burner is described and the expe­rimental researches are carried out when measuring the flame temperature of the combusted gas during the operation of the laboratory stand. The opera­ting conditions of different thermocouples in measuring the temperature of the flared gas are investigated (Fig. 2). The temperature instability in the lower and upper flames was experimentally determined (Fig. 3) and its difference from the reference data [12, 13]. The measurement of the flame temperature with a uncased thermocouple and two thermocouples of different types with protective housings is reali­zed. Methodical error of temperature measurement by different thermocouples was estimated (Fig. 5). An algorithm for the implementation of measurement control in determining the heat of combustion of natural gas according to the patented method is outlined [11]. Experimental studies of temperature changes of combusted gas mixtures at different gas flow rates and different ratios with air, which is additionally supplied for gas combustion, were carried out (Figs. 4, 7). The computer simulation (Figs. 6, 8) of the change in the flame temperature was performed on the basis of the experimental data, which allowed to obtain approximate equations of the functional dependence of the flame temperature on the gas flow rate and the ratio of the additional air and gas consumption. The possibility of realization of the device of express control of the heating value of natural gas by measuring the combustion temperature of the investigated gases, which is based on the expe­rimentally confirmed increase in the flame temperature of the investigated gases with increasing their calorific value, is substantiated (Fig. 9). The necessity of further investigation of the optimization design characteristics of the burner and the operating conditions of combustion of the gases under rapid cont­rol of their combustion heat was established (Fig. 9).

Absorption and Mass Transfer of CO2 in Monoethanolamine Solution

2016 ◽  
Vol 859 ◽  
pp. 153-157
Author(s):  
Pao Chi Chen ◽  
Sheng Zhong Lin
Keyword(s):  
Mass Transfer ◽  
Flow Rate ◽  
Liquid Flow ◽  
Gas Flow ◽  
Liquid Flow Rate ◽  
Bubble Column ◽  
Operating Conditions ◽  
Gas Flow Rate ◽  
Constant Ph ◽  
Gas Liquid Flow

This work uses a continuous bubble-column scrubber for the absorption of CO2 with a 5M MEA solution under a constant pH environment to explore the effect of the pH of the solution and gas-flow rate (Qg) on the removal efficiency (E), absorption rate (RA), overall mass-transfer coefficient (KGa), liquid flow rate (QL), gas-liquid flow ratio (γ), and scrubbing factors (φ). From the outlet CO2 concentration with a two-film model, E, RA, KGa, QL, γ, and φ can be simultaneously determined at the steady state. Depending on the operating conditions, the results show that E (80-97%), RA(2.91x10-4-10.0x10-4mol/s-L), KGa (0.09-0.48 1/s), QL(8.74-230.8mL/min), γ (0.19-5.39), and φ (0.031-0.74 mol/mol-L) are found to be comparable with other solvents. In addition, RA, KGa, E, and QL have been used to correlate with pH and Qg, respectively, with the results further explained.

Perbandingan aktivitas katalis nikel dan katalis tembaga pada reaksi hidrogenasi metil ester untuk pembuatan surfaktan

2018 ◽  
Vol 8 (2) ◽  
pp. 63
Author(s):  
Tania S Utami ◽  
Rita Arbianti ◽  
Heri Hermansyah ◽  
Wiwik Handayani ◽  
Desti Andani
Keyword(s):  
Surface Tension ◽  
Flow Rate ◽  
Gas Flow ◽  
Hydrogen Gas ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Metal Catalyst ◽  
Ni Catalyst ◽  
Gas Flow Rate ◽  
Cu Catalyst

Surfactant has ability in decreasing surface tension, interfacial surface tension, and increasing stability of emulsion systems. Surfactant is used in several industry such as soap and detergent industry, healthcare and cosmetics industry. One major advantage of oleochemical surfactant is its renewable and degradable properties regarding environmental issue. This surfactant is made using methyl esther from coconut oil through hydrogenation of methyl esther (methyl laurate) by using metal catalyst, sulfatation reaction by adding H2SO4, and neutralization by using NaOH. The goal of this research is to obtain the optimum reaction condition in aspects of several variables, such as temperature, hydrogen gas flow rate, and percent weight of catalyst in the hydrogenation reaction using Ni dan Cu catalyst. This research showed that the optimum operating conditions are 270 oC of temperature, 1 mL/s of H2 gas flow rate, and 30 %-wt of catalyst. Ni catalyst has better activity. After adding 25 %-wt of surfactants, it had surface tension of 26.4 mN/m and it could stabilize emulsion for 839 seconds. Keywords : hydrogenation, Cu catalyst, Ni catalyst, methyl esther, surfactant. Abstrak Surfaktan memiliki kemampuan menurunkan tegangan permukaan, tegangan antarmuka, dan meningkatkan kestabilan sistem emulsi. Hal ini membuat surfaktan banyak digunakan pada berbagai bidang industri seperti industri sabun, detergen, produk perawatan diri, dan kosmetika. Surfaktan berbahan baku oleokimia memiliki beberapa keunggulan, diantaranya bersifat terbarukan (renewable resources) dan secara alami mudah terdegradasi. Surfaktan ini dapat dibuat dengan menggunakan bahan baku metil ester dari minyak kelapa melalui reaksi hidrogenasi metil ester (metil laurat) dengan katalis logam, reaksi sulfatasi dengan menambahkan H2SO4, dan netralisasi dengan NaOH. Tujuan dari penelitian ini adalah mendapatkan kondisi optimum yang meliputi suhu reaksi, laju alir gas hidrogen, dan persentase berat katalis pada reaksi hidrogenasi metil laurat menggunakan katalis Ni dan Cu. Hasil penelitian menunjukkan kondisi operasi optimum yang sama dari kedua katalis, yaitu pada suhu 270 oC, laju alir gas H2 1 mL/s, dan 30 %-berat katalis. Aktivitas katalis yang lebih baik diberikan oleh katalis Ni, dengan nilai penurunan tegangan permukaan air setelah ditambahkan surfaktan sebesar 26,4 mN/m dan stabilitas emulsi minyak-air setelah ditambahkan surfaktan sebesar 839 detik. Kata Kunci : hidrogenasi, katalis Cu, katalis Ni, metil ester, surfaktan.

Effects of Slitting Size and Inlet Operating Conditions on Hydrogen Combustion Characteristics in a Micro-Combustor With a Controllable Vortex Slotted Bluff Body

2019 ◽  
Vol 142 (4) ◽  
Author(s):  
Yunfei Yan ◽  
Kaiming Shen ◽  
Yu Cui ◽  
Ziqiang He ◽  
Li Zhang ◽  
...  
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Bluff Body ◽  
Combustion Efficiency ◽  
Combustion Characteristics ◽  
Operating Conditions ◽  
Flow Ratio ◽  
Gas Flow Rate ◽  
Slit Size ◽  
Micro Combustor

Abstract Effects of controllable vortex slotted bluff body parameters (position of a bluff body, slit size, and controllable flow ratio) on the combustion characteristics of hydrogen/air in a micro-combustor with a bluff body were investigated numerically. The results illustrated that the combustion efficiency of hydrogen decreases with increasing distance (L1) between the front edge of the bluff body and the combustor inlet. The combustion characteristics of the micro-combustor are optimum when L1 is 0 mm. The blow-off limit of the combustor reaches a maximum (564 cm3/s) when the slit width (d) is 20% of the bluff body width. The blow-off limit first increases and then decreases when the equivalence ratio (φ) increases and reaches a maximum (732 cm3/s) when φ is 1.0, and the controllable flow ratio is 0.2. The combustion efficiency of hydrogen is gradually increased with the increase in the controllable flow ratio. When φ is less than 1.0, the optimal controllable flow ratio gradually decreases with the increase in the premixed gas flow rate, and the optimal controllable flow ratio basically remains at 0.6 when the premixed gas flow rate is less than 360 cm3/s.

scholarly journals CO2 Capture in A Bubble-Column Scrubber Using MEA/CaCl2/H2O Solution—Absorption and Precipitation

Crystals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 694
Author(s):  
Pao Chi Chen ◽  
Shiun Huang Zhuo
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Liquid Flow Rate ◽  
Ph Value ◽  
Bubble Column ◽  
Operating Conditions ◽  
Co2 Absorption ◽  
Gas Flow Rate ◽  
Gas Concentration ◽  
Ph Values

This study used the solvent monoethylamine (MEA)/CaCl2/H2O to investigate CO2 absorption and CaCO3 crystallization in a bubble column scrubber. The variables explored were pH, gas flow rate, gas concentration, the liquid flow rate of the solution to absorb CO2, and CaCO3 crystallization. Under a continuous mode, the solution of CaCl2 was fed continuously, and the pH dropped after CO2 absorption. To maintain the set pH value, there was an automatic input of the MEA solvent into the bubble column. In addition to maintaining the pH, the solution could also absorb CO2 and produce CaCO3 crystals, which served two purposes. The results showed that there were mainly vaterite crystals. At different pH values, the lower the pH, the higher the precipitation rate of vaterite (Fp), and vice versa. However, under different gas flow rates, the Fp decreased as the pH value increased. Additionally, the process variables also affected the absorption rate (RA) and the overall mass-transfer coefficient (KGa) generally increased with increasing pH, gas concentration, and gas flow rate. However, it slowed down under operating conditions at high pH and high gas flow rate. Finally, correlation equations for RA, KGa, and Fp were also obtained and discussed in the study.

A Characterization of the Performance of Gas Sensor Based on Heater in Different Gas Flow Rate Environments

2020 ◽  
Vol 16 (10) ◽  
pp. 6281-6290
Author(s):  
Linxi Dong ◽  
Zhongren Xu ◽  
Weipeng Xuan ◽  
Haixia Yan ◽  
Chaoran Liu ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Flow Rate ◽  
Gas Flow ◽  
Gas Flow Rate

Oligomerization of Carbon Monoxide in Plasma of the Dielectric Barrier Discharge

2016 ◽  
Vol 685 ◽  
pp. 635-638
Author(s):  
E. Litvishko ◽  
M. Goreshnev ◽  
Larisa Maletina
Keyword(s):  
Carbon Monoxide ◽  
Dielectric Barrier Discharge ◽  
Flow Rate ◽  
Gas Flow ◽  
Barrier Discharge ◽  
Methane Formation ◽  
Gas Flow Rate ◽  
Dielectric Barrier

Influence of plasma dielectric barrier discharge on oligomerization of carbon monoxide was shown. The ratio of CO and H2 was equal to 2: 1. Gas flow-rate was 3 cm3/s for H2 and 6 sm3/s for CO. It was found that methane formation is 1.2% at parameters of dielectric barrier discharge of 0.1 J. per pulse, up to 2000 pulse per second.

scholarly journals Effect of pH and Gas Flow Rate on Ozone Mass Transfer of Κ-Carrageenan Solution in Bubble Column Reactor

REAKTOR ◽  
2019 ◽  
Vol 18 (04) ◽  
pp. 177 ◽  
Author(s):  
Aji Prasetyaningrum ◽  
Dyah Arum Kusumaningtyas ◽  
Purbo Suseno ◽  
Ratnawati Ratnawati
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Flow Rate ◽  
Gas Flow ◽  
Bubble Column ◽  
Operating Conditions ◽  
Bubble Column Reactor ◽  
Gas Flow Rate ◽  
Column Reactor

This research was conducted to calculate the mass transfer coefficient value for ozonation reaction of κ-carrageenan solution in the bubble column reactor. Ozone gas was produced using ozone generator type corona discharge. In this study, operating conditions were regulated at ozone gas flow rate 2- 5 L min-1, pH 4-10, and temperature 29 ± 1 oC. Samples were tested every 5 minutes to determine the dissolved ozone concentration. The results showed that dissolved ozone concentrations increased with increasing ozonation time and ozone gas flow rate. However, a very high gas flow rate can increase turbulence so that the mass transfer coefficient (kLa) value decreased. In alkaline conditions, the formation of free radicals (HO*) increases so that the amount of dissolved ozone decreases. The kLa value of ozone gas in κ-carrageenan solution is slightly lower than the kLa value of the ozone gas in the water. The results of this study indicate that (kLa) ozone gas in water is 0.131 / minute while the value (kLa) in κ-carrageenan solution is 0.128 / minute.

Computational Analysis of a Three-Dimensional Plasma Spray Jet

1997 ◽  
Author(s):  
B. Dussoubs ◽  
P. Fauchais ◽  
A. Vardelle ◽  
M. Vardelle ◽  
N.J. Themelis
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Control Volume ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Gas Flow Rate ◽  
Fluid Turbulence ◽  
Energy Equations ◽  
S Model ◽  
Carrier Gas Flow

Abstract An analysis of a d.c. plasma jet is presented using a three-dimensional commercial fluid dynamics code, ESTET. This code solves the coupled conservation equations of mass, species, momentum and thermal energy equations for a compressible and turbulent fluid in control volume and finite difference formulation. Computations take into account fluid turbulence using a standard k-s model with the Launder and Sharma correction for the laminar zones, e.g. the plasma core. Two series of spraying conditions differing in the total gas flow rate (30 and 60 slm) and the arc current (300 and 600 A, respectively) are computed. The process parameters are independently varied about the nominal operating conditions. The effect of the variation of primary and secondary gas flow rate, effective power and powder carrier gas flow rate on flow fields characteristics, is discussed.

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