scholarly journals Low concentration volatile organic pollutants removal in combined adsorber-desorber-catalytic reactor system

2008 ◽  
Vol 62 (2) ◽  
pp. 51-58
Author(s):  
Zorana Arsenijevic ◽  
Gordan Savcic ◽  
Dragan Rankovic ◽  
Bosko Grbic ◽  
Nenad Radic ◽  
...  

The removal of volatile organic compounds (VOCs) from numerous emission sources is of crucial importance due to more rigorous demands on air quality. Different technologies can be used to treat the VOCs from effluent gases: absorption, physical adsorption, open flame combustion, thermal and catalytic incineration. Their appropriateness for the specific process depends on several factors such as efficiency, energy consumption, secondary pollution, capital investments etc. The distinctive features of the catalytic combustion are high efficiency and selectivity toward be?nign products, low energy consumption and absence of secondary polluti?on. The supported noble catalysts are widely used for catalytic incineration due to their low ignition temperatures and high thermal and chemical stability. In our combined system adsorption and desorption are applied in the spouted bed with draft tube (SBDT) unit. The annular zone, loaded with sorbent, was divided in adsorption and desorption section. Draft tube enabled sorbent recirculation between sections. Combustion of desorbed gases to CO2 and water vapor are realized in additive catalytic reactor. This integrated device provided low concentrations VOCs removal with reduced energy consumption. Experiments were conducted on a pilot unit of 220 m3/h nominal capacity. The sorbent was activated carbon, type K81/B - Trayal Corporation, Krusevac. A sphere shaped commercial Pt/Al2O3 catalyst with "egg-shell" macro-distribution was used for the investigation of xylene deep oxidation. Within this paper the investigations of removal of xylene vapors, a typical pollutant in production of liquid pesticides, in combined adsorber/desorber/catalytic reactor system is presented.

Author(s):  
Yanbo Li ◽  
Shuhe Han ◽  
Liping Zhang ◽  
Yifu Yu

AbstractWith the development of industrialization, the emission of volatile organic compounds (VOCs) to atmosphere causes serious environmental problems and the treatment of VOCs needs to consume a lot of energy. Moreover, indoor VOCs are seriously harmful to human health. Thus, there is an urgent requirement for the development of indoor VOCs treatment technologies. Catalytic degradation of VOCs, as a low energy consumption, high efficiency, and easy to achieve manner, has been widely studied in related fields. As a kind of transition metal catalyst, manganese-based catalysts have attracted a lot of attention in the catalytic degradation of VOCs because of their unique advantages including high efficiency, low cost, and excellent stability. This paper reviews the state-of-the-art progress of manganese-based catalysts for VOCs catalytic degradation. We introduce the thermocatalytic, photocatalytic and photo-thermocatalytic degradation of VOCs on manganese-based catalysts in this paper. The optimization of manganese-based catalysts by means of structural design, decorating modification and defect engineering is discussed. Graphical Abstract


2004 ◽  
Vol 69 (12) ◽  
pp. 1129-1144 ◽  
Author(s):  
Zorana Arsenijevic ◽  
Zeljko Grbavcic ◽  
Bosko Grbic

The removal of ethylene oxide (EtO) in a combined system adsorber desorber/catalytic reactor has been investigated. The combined system was a modified draft tube spouted bed reactor loaded with Pt/Al2O3 catalyst. The annular region was divided into two sectons, the "hot" section contained about 7 % of catalyst and it behaved as a desorber and catalytic incinerator while the "cold" section, with the rest of the catalyst, behaved as a sorber. The catalyst particles were circulated between the two sections by use of a draft tube riser. The Computational Fluid Dynamics (CFD) program package FLUENT was used for simulations of the operation of the combined system. In addition, a one-dimensional numerical model for the operation of the packed bed reactor was compared with the corresponding FLUENT calculations. The results of the FLUENT simulations are in very good agreement with the experimental observations, as well as with the results of the one-dimensional numerical simulations.


1987 ◽  
Vol 19 (3-4) ◽  
pp. 391-400 ◽  
Author(s):  
Zhou Ding ◽  
Cai Wei Min ◽  
Wang Qun Hui

This paper studies the use of bipolar-particles-electrodes in the decolorization of dyeing effluents. Treatment of highly colored solutions of various soluble dyes (such as direct, reactive, cationic or acid dyes) and also samples of dyeing effluents gave rise to an almost colorless transparent liquid, with removal of CODcr and BOD5 being as high as over 80%. The method is characterized by its high efficiency, low energy consumption and long performance life. A discussion of the underlying principle is given.


Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1325
Author(s):  
Zhongwei Gao ◽  
Changqing Pan ◽  
Chang-Ho Choi ◽  
Chih-Hung Chang

Water pollution is a growing global issue; there are many approaches to treating wastewater, including chemical coagulation, physical adsorption, and chemical oxidation. The photocatalysis process has provided a solution for removing pollutants from wastewater, where the pair of the photoelectron and hole works through an asymmetric way to degrade the contaminants under UV irradiation. This method offers an alternative route for treating the pollutant with a lower energy cost, high efficiency, and fewer byproducts. A continuous-flow microfluidic reactor has a channel size from tens to thousands of micrometers, providing uniform irradiation and short diffusion length. It can enhance the conversion efficiency of photocatalysis due to the simple spatial symmetry inside the microreactor channel and among the individual channels. In addition, the bandgap of TiO2, ZnO, or other photocatalyst nanoparticles with symmetric crystal structure can be modified through doping or embedding. In this mini-review, a review of the reported continuous-flow photocatalytic microfluidic reactor is discussed from the perspective of both microreactor design and material engineering.


2015 ◽  
Vol 659 ◽  
pp. 570-574 ◽  
Author(s):  
Apinya Musidang ◽  
Nantana Jiratumnukul

UV-curable process is widely used for paints, inks and adhesives due to its rapid curing, low energy consumption, high efficiency and low volatile organic compounds (VOCs). The objective of this research is to prepare poly(lactic acid) (PLA) based UV-curable coating by using glycolyzed PLA. PLA was glycolyzed by ethylene glycol (EG) at 170°C for 90 minutes. The obtained glycolyzed PLA was reacted with methacrylic anhydride (MAAH) to provide PLA acrylate oligomer. The obtained PLA acrylate oligomer was used in coating formulations with various amounts of photoinitiator and cured under UV radiation. Physical properties of cured coating film were investigated such as pencil hardness, gloss and haze. The results showed that poly(lactic acid) (PLA) based UV-curable coating provided good physical properties.


2014 ◽  
Vol 60 (2) ◽  
pp. 193-198
Author(s):  
M. Yousefi ◽  
D. Koozehkanani ◽  
H. Jangi ◽  
N. Nasirzadeh ◽  
J. Sobhi

Abstract A 400 MHz high efficiency transmitter for wireless medical application is presented in this paper. Transmitter architecture with high-energy efficiencies is proposed to achieve high data rate with low power consumption. In the on-off keying transmitters, the oscillator and power amplifier are turned off when the transmitter sends 0 data. The proposed class-e power amplifier has high efficiency for low level output power. The proposed on-off keying transmitter consumes 1.52 mw at -5 dBm output by 40 Mbps data rate and energy consumption 38 pJ/bit. The proposed transmitter has been designed in 0.18μm CMOS technology.


2008 ◽  
Vol 58 ◽  
pp. 83-89
Author(s):  
Ning Chang Liu ◽  
Zhao Feng Li

In cement industry, many grinding up systems are on operating now. The tradition process of tube mill grinding system is high energy consumption, so it’s low efficiency, especially in the final cement grinding process. The value and advantage of slag is recognized more and more, but it’s difficult to be grinded up. Furthermore, the disadvantage and shortages to grind up clinker compounded with slag to produce cement are obvious and adopted. The best process is to grind up slag, clinker separately. Then, these two kinds of powder are compounded by a mixer. Hereby, it introduces a design of the process to grind up clinker, slag by one roller mill.


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