共查询到20条相似文献,搜索用时 15 毫秒
1.
Kwang Joong Oh Ki Chul Cho Young Hean Choung Suk Kyong Park Sung Ki Cho Donguk Kim 《Korean Journal of Chemical Engineering》2006,23(1):148-152
The dominant off gases from publicly owned treatment works include hydrogen sulfide, benzene, and toluene. In this research,
hydrogen sulfide oxidized byBacillus cereus, and benzene with toluene were removed by VOC-degrading microbial consortium. The optimum operating condition of the fluidized
bed bioreactor including both microorganisms was 30 ‡C, pH 6–8, and 150 cm of liquid bed height. The critical loading rate
of hydrogen sulfide, benzene and toluene in the bioreactor was about 15 g/m3h, 10 g/m3h and 12 g/m3h, respectively. The fluidized bed bioreactor showed an excellent elimination capacity for 580 hours of continuous operation,
and maintained stable removal efficiency at sudden inlet concentration changes. 相似文献
2.
Oh Kwang Joong Young Sik Kim Sung Ki Cho Donguk Kim 《Korean Journal of Chemical Engineering》2002,19(6):1026-1029
A fluidized bed bioreactor including microbial consortium was used to remove benzene and toluene simultaneously. The microbial
consortium was obtained from sewage treatment plant, and showed maximum benzene degradation rate of 45.2 mg/l·h·mg cell in
30 °C and pH 7.0, and maximum toluene degradation rate of 44.4 mg/l·h·mg cell in 30 °C and pH 8.0. The optimum operating condition
of the fluidized bed bioreactor was 30 °C, pH 7.0 and 150 cm of liquid bed height. The average removal efficiency of benzene
was 94% for inlet concentration of 53(±5) ppm benzene and that of toluene was 96% for an inlet concentration 48(±5) ppm toluene
at 600 l/h of gas volumetric flow rate. The maximum removal capacity in the experimental condition was 22.3 g/m3·h for benzene and 16.3 g/ m3·h for toluene.
This paper is dedicated to Professor Dong Sup Doh on the occasion of his retirement from Korea University. 相似文献
3.
Gwi-Taek Jeong Gwang-Yeon Lee Jin-Myoung Cha Don-Hee Park 《Korean Journal of Chemical Engineering》2008,25(1):118-123
In order to develop a method for the removal of hydrogen sulfide via a biological process, two different packing materials
were tested to assess their capabilities as biofilter bed materials under variable conditions of two parameters: inlet gas
concentration and inlet gas flow rate. We detected a maximal elimination capacity (critical loading rate) of 515.1 (410.5)
g-H2S/m3·hr, and 415.5 (80.0) g-H2S/m3·hr, respectively, when polypropylene fibrils and volcanic stone were employed as supporting materials. The results of this
study show that the application of polypropylene fibrils might be a favorable choice as a packing material in biofilter for
the biological removal of hydrogen sulfide. 相似文献
4.
Young-Soo?Na Do-Han?Kim Chang-Han?Lee Song-Woo?Lee Young-Seek?Park You-Kwan?Oh Sung-Hoon?Park Seung-Koo?Song
Photocatalytic degradation of organic contaminants in wastewater by TiO2 has been introduced in both bench and pilot-scale applications in suspended state or immobilized state on supporting material.
TiO2 in suspended state gave less activity due to its coagency between particles. Recent advances in environmental photocatalysis
have focused on enhancing the catalytic activity and improving the performance of photocatalytic reactors. This paper reports
a preliminary design of a new immobilized TiO2 photocatalyst and its photocatalytic fluidized bed reactor (PFBR) to apply photochemical degradation of a dye, Rhodamine
B (RhB). But it was not easy to make a cost-effective and well activated immobilized TiO2 particles. A kind of photocatalyst (named Photomedium), consisting of hollow ceramic balls coated with TiO2-sol, which was capable of effective photodegradation of the dye, has been presented in this study. The photocatalytic oxidation
of RhB was investigated by changing Photomedia concentrations, initial RhB concentrations, and UV intensity in PFBR
This paper is dedicated to Professor Hyun-Ku Rhee on the occasion of his retirement from Seoul National University. 相似文献
5.
Chien-Song Chyang Hou-Peng Wan Li-Chi Su 《Korean Journal of Chemical Engineering》2007,24(6):1106-1112
A systematic investigation on elutriation behavior conducted in a vortexing fluidized bed (VFB) cold model is studied. The
effects of various parameters on the elutriation are investigated from the data obtained by using ‘response surface methodology’
(RSM) to determine the relationship between elutriation rate and operating conditions. The results show that all the interactions
among primary air flow rate, secondary air flow rate, fine particle size, secondary air inlet diameter, and imaginary circle
diameter had significant influences on elutriation behavior in the VFB. The modified regression models of the ‘specific elutriation
rate constant’ (K*) were also submitted in this study. 相似文献
6.
The drying characteristics of water treatment process (WTP) sludge were investigated with a fluidized bed. The equilibrium
moisture ratio of WTP sludge increased with relative humidity and decreased with temperature of drying air. However, equilibrium
moisture ratio of WTP sludge was more sensitively dependent on relative humidity than temperature of drying air. When the
sludge was dried in a batch fluidized bed, the drying rate of sludge decreased as the moisture ratio of sludge in the bed
decreased. The periods of constant drying rates were apparently not observed on the drying rate curves. In addition, the maximum
drying rates were increased with bed temperature and superficial air velocity. As the fluidized bed was operated continuously,
the degree of drying of WTP sludge increased with bed temperature but was weakly dependent on superficial air velocity. However,
the drying efficiency was decreased with bed temperature and relatively insensitive to superficial air velocity and increased
with feed rate of sludge. 相似文献
7.
Jae Uk Jung Wooseok Nam Ki June Yoon Gui Young Han 《Korean Journal of Chemical Engineering》2007,24(4):674-678
A fluidized bed reactor made of quartz tube with an I.D. of 0.055 m and a height of 1.0 m was employed for the thermocatalytic
decomposition of methane to produce CO2 — free hydrogen. The fluidized bed was used for continuous withdrawal of the carbon products from the reactor. Two kinds
of carbon catalysts — activated carbon and carbon black — were employed in order to compare their catalytic activities for
the decomposition of methane in the fluidized bed. The thermocatalytic decomposition of methane was carried out in a temperature
range of 800–925°C, using a methane gas velocity of 1.0–3.0 U
mf
and an operating pressure of 1.0 atm. Distinctive difference was observed in the catalytic activities of two carbon catalysts.
The activated carbon catalyst exhibited higher initial activity which decreased significantly with time. However, the carbon
black catalyst exhibited somewhat lower initial activity compared to the activated carbon catalyst, but its activity quickly
reached a quasi-steady state and was sustained over time. Surfaces of the carbon catalysts before and after the reaction were
observed by SEM. The effect of various operating parameters such as the reaction temperature and the gas velocity on the reaction
rate was investigated. 相似文献
8.
The slug flow behavior of polyethylene particles was examined in a fluidized bed of 7 cm ID and 50 cm in height. The employed
polymer particles were high density polyethylene (HDPE) with the average particle size of 603 μm. The slugging flow of polyethylene
particles was analyzed from the measured pressure drop signals by classical statistical methods such as absolute average deviation,
probability density function, power spectrum, auto-cor-relation, and cross-correlation. The results show that in spite of
high dielectric constant of polymer particles, the slugging phenomena such as incipient slugging velocity, slugging frequency
and slugging rise velocity were very similar to the Geldart B type non-polymeric particles. It was observed that slug frequencies
decreased with gas velocity and the limiting slug frequency was observed for the gas velocities in this study. 相似文献
9.
Slugging experiments were performed in a fluidized bed of 7 cm ID and 50 cm in height to examine the maximum bed height with an expanded section. High-density polyethylene (HDPE) particles of 0.5 mm were employed as the bed materials. The slugging bed height was linearly increased with the gas velocity in the beds of uniform cross section as well as expanded section with different slope. From the results of this study, it was found that the existing correlation to predict the slugging bed height based on the heavier particles for the uniform cross section area was satisfactorily applied for the lighter particles of HDPE and for the expanded section, a slight modification was made for the particle of HDPE in the slugging bed. Presented at the Int’/Sym. on Int’l Symp. on Chem. Eng. (Cheju, Feb. 8–10, 2001), dedicated to Prof. H. S. Chun on the occasion of his retirement from Korea University. 相似文献
10.
Woon-Jae Lee Sang-Done Kim Byung-Ho Song 《Korean Journal of Chemical Engineering》2002,19(6):1091-1096
To produce low calorific value gas, Australian coal has been gasified with air and steam in a fluidized bed reactor (0.1 m-I.Dx1.6
m-high) at atmospheric pressure. The effects of fluidizing gas velocity (2–5 Uf/Umf), reaction temperature (750–900 °C), air/coal ratio (1.6-3.2), and steam/coal ratio (0.63–1.26) on gas composition, gas yield,
gas calorific value of the product gas and carbon conversion have been determined. The calorific value and yield of the product
gas, cold gas efficiency, and carbon conversion increase with increasing fluidization gas velocity and reaction temperature.
With increasing air/coal ratio, carbon conversion, cold gas efficiency and yield of the product gas increase, but the calorific
value of the product gas decreases. When steam/coal ratio is increased, cold gas efficiency, yield and calorific value of
the product gas increase, but carbon conversion is little changed. Unburned carbon fraction of cyclone fine decreases with
increasing fluidization gas velocity, reaction temperature and air/coal ratio, but is nearly constant with increasing steam/coal
ratio. Overall carbon conversion decreases with increasing fluidization velocity and air/ coal ratio, but increases with increasing
reaction temperature. The particle entrainment rate increases with increasing fluidization velocity, but decreases with increasing
reaction temperature.
This paper is dedicated to Professor Dong Sup Doh on the occasion of his retirement from Korea University. 相似文献
11.
Jonghoon Kim 《Korean Journal of Chemical Engineering》1999,16(6):840-842
The aim of this work was to study the mechanism of solid circulation in a Circulating Fluidized Bed pilot as a function of secondary air flow rate A rectangular column of 7 m height equipped with a U type siphon was used for this purpose The results obtained showed that the solid circulating phenomenon depends on different limiting steps like feeding step (dense bed), siphon circulating capacity and suspension saturation capacity. 相似文献
12.
A fluidized bed reactor has been developed to overcome the plugging problem of urea injection by employing a sparger rather
than nozzles in the SNCR process for simultaneous removal of SO2 and NOx. In a developed fluidized bed reactor, the optimum temperature to remove NOx is shifted to lower values, the reaction temperature window is widened with the presence of CO in flue gas, and NO conversion
is higher than that in a flow reactor. The optimum amount of urea injection in the reactor is found to be above 1.2 based
on the normalized stoichiometric molar ratio (NSR) with respect to NO conversion. In the simultaneous removal of SO2/NO, conversions of SO2 and NO reach 80–90%, nearly the same values for the individual removal of SO2 and NO above 850 ‡C. 相似文献
13.
The gas backmixing characteristics in a circulating fluidized bed (0.1 m-IDx5.3-m high) have been determined. The gas backmixing
coefficient (Dba) from the axial dispersion model in a low velocity fluidization region increases with increasing gas velocity. The effect
of gas velocity onD
ba in the bubbling bed is more pronounced compared to that in the Circulating Fluidized Bed (CFB). In the dense region of a
CFB, the two-phase model is proposed to calculate Dbc from the two-phase model and mass transfer coefficient (k) between the crowd phase and dispersed phase. The gas backmixing
coefficient and the mass transfer coefficient between the two phases increase with increasing the ratio of average particle
to gas velocities (Up/Ug). 相似文献
14.
Jun Sik Kim Hak Ki Kim Sang Bong Lee Myoung Jae Choi Kyu Wan Lee Yong Kang 《Korean Journal of Chemical Engineering》2001,18(4):463-467
Characteristics of CO2 hydrogenation were investigated in a fluidized bed reactor (0.052 m IDxl.5 m in height). Coprecipitated Fe-Cu-K-Al catalyst
(dρ=75–90 Μm) was used as a fluidized solid phase. It was found that the CO2 conversion decreases but the CO selectivity increases, whereas the space-time-yield attains maximum values with increasing
gas velocity. The CO2 conversion has increased, but CO selectivity has decreased with increasing hydrogenation temperature, pressure or H2/CO2 ratio in the fluidized bed reactor. Also, the CO, conversion and olefin selectivity appeared to be higher in the fluidized
bed reactor than those of the fixed bed reactor.
Presented at the Int’l Symp. on Chem. Eng. (Cheju, Feb. 8–10, 2001), dedicated to Prof. H. S. Chun on the occasion of his
retirement from Korea University 相似文献
15.
This study investigated the effects of high temperature and combustion conditions on the attrition of fluidized material in
a fluidized bed. Silica sand was fluidized in air at an atmospheric pressure between 873 K and 1,073 K. The operating parameters
evaluated in investigating the attrition rate of fluidized material included particle size, temperature and both combustion
and non-combustion conditions. Experimental results indicated that the total weight of attrition increased with increasing
temperature and decreased with increasing particle size. The attrition was higher during the initial fluidization period than
the later period, due to the loss of sharp corners and edges of the attrition particles. The initial and final attrition rates
during combustion were higher than those in the non-combustion condition, because the heat and thermal shock were produced
to increase attrition rate during incineration. Comparing the experimental data with previous correlations, that reveals a
significant level of error in the prediction results from existing correlations. This error may occur because the experimental
equations neglected the operating temperature and particle size. 相似文献
16.
Chaiwat Prompubess Lursuang Mekasut Pornpote Piumsomboon Prapan Kuchontara 《Korean Journal of Chemical Engineering》2007,24(6):989-995
In this research, co-combustion of coal and rice husk was studied in a circulating fluidized bed combustor (CFBC). The effects
of mixed fuel ratios, primary air and secondary air flow rates on temperature and gas concentration profiles along riser (0.1
m inside diameter and 3.0 m height) were studied. The average particle size of coal from Maetah used in this work was 1,128
mm and bed material was sand. The range of primary air flow rates was 480–920 l/min corresponding to U
g
of 1.0–2.0 m/s for coal feed rate at 5.8 kg/h. The recirculation rate through L-valve was 100 kg/hr. It was found that the
temperatures along the riser were rather steady at about 800–1,000 degrees Celsius. The introduction of secondary air improved
combustion and temperature gradient at the bottom of the riser, particularly at a primary air flow rate below 1.5 m/s. Blending
of coal with biomass, rice husk, did improve the combustion efficiency of coal itself even at low concentration of rice husk
of 3.5 wt%. In addition, the presence of rice husk in the feed stocks reduced the emission of both NO
x
and SO2. 相似文献
17.
The purpose of this paper is to investigate, both theoretically and experimentally, hydrogen production from agro-industrial by-products using a continuous bioreactor packed with a mixture of spongy and glass beads and inoculated with Enterobacter aerogenes. Replicated series of experimental runs were performed to study the effects of residence time on hydrogen evolution rate and to characterize the critical conditions for the wash out, as a function of the inlet glucose concentration and of the fluid superficial velocity. A further series of experimental runs was focused on the effects of both residence time and inlet glucose concentration over hydrogen productivity. A kinetic model of the process was developed and showed good agreement with experimental data, thus representing a potential tool to design a large-scale fermenter. In fact, the model was applied to the optimal design of a bioreactor suitable of feeding a phosphoric acid fuel cell of a target power. 相似文献
18.
An axial dispersion of gas in a circulating fluidized bed was investigated in a fluidized bed of 4.0 cm I.D. and 279 cm in
height. The axial dispersion coefficient of gas was determined by the stimulus-response method of trace gas of CO2. The employed particles were 0.069 mm and 0.147 mm silica-sand. The results showed that axial dispersion coefficients were
increased with gas velocity and solid circulation rates as well as suspension density. The experimentally determined axial
dispersion coefficients in this study were in the range of 1.0-3.5 m2/s. 相似文献
19.
Young Hean Choung Ki Chul Cho Won Joon Choi Soo Gon Kim Young Suk Han Kwang Joong Oh 《Korean Journal of Chemical Engineering》2007,24(4):660-663
Fluidized bed pyrolysis has been recognized as an innovative technology for sewage sludge treatment. The physical and attrition
properties of sewage sludge are changed through the fluidized bed pyrolysis. The minimum fluidization velocities and attribution
rate constants for sewage sludge and sludge based-char were obtained from pressure drop and attribution tests. As a result,
sewage sludge with 20% moisture content and char were classified as Geldart B solids and the superficial gas velocity for
bubbling fluidization was 0.2142-0.8755 m/s. In addition, attribution of the sewage sludge and char was more affected by particle
size than by material type. The equations for the overall attrition rate constants are K
a
× 105 = 1.09U − 14.82 for sludge and ln k
a
= 0.1(U−U
mf
)− 13.63 for char, respectively. 相似文献
20.
Hong Il Cho Chan-Hwa Chung Gui Young Han Gui Ryong Ahn Jong Su Kong 《Korean Journal of Chemical Engineering》2000,17(3):292-298
Gas mixing behavior was investigated in a residence time distribution experiment in a bubbling fluidized bed of 0.07 m ID
and 0.80 m high. Linear low density polyethylene (LLDPE) particles having a mean diameter of 772 Μm and a particle size range
of 200-1,500 Μm were employed as the bed material. The stimulus-response technique with CO2 as a tracer gas was performed for the RTD study. The effects of gas velocity, aspect ratio (H0/D) and scale-up on the axial gas dispersion were determined from the unsteady-state dispersion model, and the residence time
distributions of gas in the fluidized bed were compared with the ideal reactors. It was found that axial dispersion depends
on the gas velocity and aspect ratio of the bed. The dimensionless dispersion coefficient was correlated with Reynolds number
and aspect ratio. 相似文献