Removal of azimsulfuron and zoxamide using a tapered variable diameter biological fluidized bed combined with electrochemistry: mass fraction division, energy metabolism activity and carbon emissions

2021 ◽  
pp. 126518
Author(s):  
Liqiang Yu ◽  
Wenyu Liu ◽  
Lixue Liu ◽  
Jian Dong ◽  
Fei Han ◽  
...  
2018 ◽  
Vol 2 (1) ◽  
pp. 40
Author(s):  
Mochammad Agung Indra Iswara ◽  
Tantular Nurtono ◽  
Sugeng Winardi

Penelitian ini bertujuan untuk mengetahui fenomena pembakaran batubara dimana dimensi alat, distribusi ukuran partikel, dan jenis kualitas batubara menggunakan validasi dari penelitian Wang. Penelitian ini mengarahkan pada simulasi berbasis CFD. Kondisi operasi pada saat simulasi pembakaran dilakukan pada kecepatan bubbling. Metode yang digunakan sebelum melakukan simulasi pembakaran merupakan kelanjutan dari simulasi fluidisasi dimana masih menggunakan geometri 2-D fluidized bed lalu dilakukan meshing, selanjutnya memasukkan persamaan energi. Geometri fluidized bed yang digunakan berbentuk tabung dengan panjang silinder fluidized bed 1370 mm, diameter silinder 152 mm. Bahan yang digunakan pada penelitian ini berupa pulverized coal dengan jenis batubara Bituminous dimana ukuran partikel dianggap polydisperse dengan ukuran partikel 1 mm dan 1,86mm yang masing-masing sebesar 50% fraksi massa dengan kecepatan 0,2 Kg/s dan suhu 1200 K, dan udara luar yang diinjeksikan dengan kecepatan 0,8 m/s dan suhu 300 K. Analisa pengambilan data adalah berupa kontur fase padatan, kontur temperatur pada fase-1 dan fase padatan, fraksi massa produk pembakaran, massa padatan awal dan akhir simulasi dengan time step sebesar 0,0001 detik dan number of time step sebesar 300000. Selanjutnya data tersebut diplot menjadi grafik temperatur terhadap time step dan disajikan dalam setiap 1 menit simulasi selama 5 menit simulasi.This research aims to determine coal combustion’s phenomenon, where the device’s dimension, particle size distribution, and the quality of rank coal  which validated Wang’s reseach. This reseach leads on CFD simulation. The operation condition has did in bubbling velocity. This method is a continuation from fluidization simulation which is use 2-D Geometry and then used the meshing method, and enter the energy equation. The geometry of fluidized bed used was tubular cylinder with 1370 mm length and 152 mm. Materials used in this study was pulverized coal with Bituminous coal type which the particle size was considered as monodispers with particle size was 1.43 mm and polydispersed with particle size was 1 mm with 50% mass fraction and 1.86 mm with 50% mass fraction with flow rate 0,2 Kg/s and the temperature is 1200 K, and the outside air are injected in 0,8 m/s and 300 K. The analysis of data retrieval is solid phase contour, temperature contours in phase-1 and solid phase, mass fraction of combustion product, initial solid mass and final solid mass simulation with time step 0,0001 s and the numberof time step 300000. Then the data is plotted into a graph temperature vs time step and presented in 1 minute simulation for 5 minute simulation.


2015 ◽  
Vol 17 (2) ◽  
pp. 236-247

<div> <p>Attrition of limestone particles in bubbling fluidized bed has significant influence on cyclic CO<sub>2</sub> capture ability of sorbents. The limestone particle attrition and size distribution characteristics were investigated experimentally in a bench scale fluidized bed. The effects of initial particle sizes, fluidized velocity, attrition time and temperature on limestone attrition characteristics were studied. An empirical fitting correlation was proposed to describe the relationship of cumulative mass fraction of limestone fines (<em>R</em>) and attrition time (<em>t</em>). The results show that the fines generation rate decreases and particle size reduction rate increases with increasing initial size. Chipping of large particle takes predominant position when fluidized velocity exceeds the minimum fluidization velocity resulting in more prominent reduction of particle size. After 4 hours attrition, particle size reduction and fines generation rate become constant. It is suggested that cumulative mass fraction of limestone fines (<em>R</em>) increases with attrition time with a function of decaying exponential correlation.</p> </div> <p>&nbsp;</p>


Author(s):  
Saad A. El-Sayed ◽  
Amro A. El-baz ◽  
Emad H. Noseir

Abstract Mixing and segregation characteristics of biomass particles are of practical importance because the in-bed combustion efficiency of volatile matter affects the vertical location of biomass in bubbling fluidized bed combustor. Sesame and broad bean stalk biomass materials mixed with sand used in this study. The superficial gas velocity, biomass chip length, sand particle size and mass fraction of biomass varied as experimental variables. The mixing and segregation behavior of mixtures were analyzed in terms of mixing index. It was found that the variability in the chip-shape made the sesame chips is quantitatively and qualitatively higher homogeneity and mixedness than the broad bean chips. The optimum overall mixing index for the sesame and the broad bean is around 0.96 and 0.84 at dimensionless superficial gas velocity (U/Umf) of 2.0 (1.40 m/sec) and 2.1 (1.25 m/sec), respectively. It was found that as the mean diameter increased and the sphericity decreased, the mixing quality decreased. The average sand particle size of 371 µm can keep good mixing with biomass chips of both materials, compared with average particle sizes of sand 550 and 700 µm. Increasing the initial biomass mass fraction yields a poor mixing of the investigated biomass stalks.


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Chao Chen ◽  
Xuan Wu ◽  
Lingling Zhao

A 2D dynamic model for a bubbling fluidized bed (BFB) combustor has been developed for simulating the coal and biomass cofiring process under 21% O2/79% CO2 atmosphere in a 6 kWth bubbling fluidized bed, coupled with the Euler-Euler two-phase flow model. The kinetic theory of binary granular mixtures is employed for the solid phase in order to map the effect of particle size and density. The distribution of temperature, volume fraction, velocity, gas species concentration, and reaction rates are studied with numerical calculations. The simulated temperature distribution along the height of the combustor and outlet gas concentrations show good agreement with experimental data, validating the accuracy and reliability of the developed cofiring simulation model. As indicated in the results, there are two high temperature zones in the combustor, which separately exist at the fuel inlet and dilute phase. The reaction rates are related to the species concentration and temperature. The higher concentration and temperature lead to the larger reaction rates. It can be seen that all of the homogeneous reaction rates are larger at the fuel inlet region because of rich O2 and volatiles. High mass fraction of volatile gas is found at the fuel inlet, and the main reburning gas at the dilute phase is CH4. The mass fraction distribution of CO is related to the volume fraction of fuel which is due to the fact that the source of CO is not only from the devolatilization but also from the gasification. On the basis of this theoretical study, a better understanding of flow and combustion characteristics in biomass and coal cofiring under oxy-fuel atmospheres could be achieved.


Author(s):  
Amreek Singh ◽  
Judith M. McLaren ◽  
Onkar S. Atwal ◽  
Peter Eyre

Introduction3-methylindole (MI), a rumen metabolite of the amino acid L-tryptophan, has been shown to produce bovine pulmonary edema and emphysema. The airways contain free and exfoliated cells. A morphologic analysis of these cells may complement the understanding of the mechanism of lung edema. Ultrastructure of the bronchopulmonary lavage (BL) cells 24 h following MI oral administration to calves is described in this experiment. The 12 hours post-treatment results were described earlier.Materials and MethodsTwo Holstein-Friesian calves were each administered an oral dose of 0.2 g MI/Kg body weight and another two calves served as controls. The animals were euthanized with sodium pentabarbitol 24 h after receiving the compound. The lungs and trachea were removed and 0.1 M sodium phosphate buffered saline was infused into the lungs through the trachea. Glutaraldehyde fixative was added to the recovered BL fluid so as to form a 1% solution. The fluid was centrifuged and the resulting cell pellet was suspended in the buffer. The procedures were repeated on the suspension; the pellet was post-fixed in osmium tetroxide and was processed by conventional methods of section preparations for TEM examination. Lung samples from caudal lobes were fixed in 1.5% glutaraldehyde to obtain tissue sections for TEM.Results and DiscussionPulmonary alveolar macrophages (AM), neutrophils, ciliated epithelial cells, globule leukocytes and plasma cells were recovered from the BL fluid of the control and Mi-administered calves. Ciliated cells and globule leukocytes could not be harvested from the controls. The AM obtained from the treated calves (Fig. 1) in comparison with similar cells from the controls were larger, and contained large membrane-limited inclusions (phagolysosomes). There was a remarkable similarity between the lavaged AM and the AM studied in thin sections of lung (cf. Fig. 1 and Fig. 2). The neutrophil was the second most abundant cell type retrieved from the lavage fluid from the calves of control or treated group. Except for scanty pseudopodia in the neutrophils obtained from the Mi-receiving calves, the cells appeared unaltered (Fig. 3). Ciliated cells were abundant in the BL fluid of Mi-ingesting calves. A heterogeneous collection of vesicles filled the ciliated cell cytoplasm (Fig. 3). Globule leukocytes were commonly observed among BL cells of treated calves. The globule leukocytes were ca. 15 μm in diameter and contained round or elliptical nuclei with conspicuous nucleoli. The cytoplasmic granules, which are a prominent feature of globule leukocytes, were electron-opaque and had a variable diameter (0.5-3.0 μm). A one-line account of globule leukocytes in the bronchi of steers administered MI has appeared. Plasma cells were rare. Ultrastructure of BL cells is compatible with their response to chemical insult by MI.


Author(s):  
B. D. Athey ◽  
A. L. Stout ◽  
M. F. Smith ◽  
J. P. Langmore

Although there is general agreement that Inactive chromosome fibers consist of helically packed nucleosomes, the pattern of packing is still undetermined. Only one of the proposed models, the crossed-linker model, predicts a variable diameter dependent on the length of DNA between nucleosomes. Measurements of the fiber diameter of negatively-stained and frozen- hydrated- chromatin from Thyone sperm (87bp linker) and Necturus erythrocytes (48bp linker) have been previously reported from this laboratory. We now introduce a more reliable method of measuring the diameters of electron images of fibrous objects. The procedure uses a modified version of the computer program TOTAL, which takes a two-dimensional projection of the fiber density (represented by the micrograph itself) and projects it down the fiber axis onto one dimension. We illustrate this method using high contrast, in-focus STEM images of TMV and chromatin from Thyone and Necturus. The measured diameters are in quantitative agreement with the expected values for the crossed-linker model for chromatin structure


Author(s):  
W.A. Jacob ◽  
R. Hertsens ◽  
A. Van Bogaert ◽  
M. De Smet

In the past most studies of the control of energy metabolism focus on the role of the phosphorylation potential ATP/ADP.Pi on the regulation of respiration. Studies using NMR techniques have demonstrated that the concentrations of these compounds for oxidation phosphorylation do not change appreciably throughout the cardiac cycle and during increases in cardiac work. Hence regulation of energy production by calcium ions, present in the mitochondrial matrix, has been the object of a number of recent studies.Three exclusively intramitochondnal dehydrogenases are key enzymes for the regulation of oxidative metabolism. They are activated by calcium ions in the low micromolar range. Since, however, earlier estimates of the intramitochondnal calcium, based on equilibrium thermodynamic considerations, were in the millimolar range, a physiological correlation was not evident. The introduction of calcium-sensitive probes fura-2 and indo-1 made monitoring of free calcium during changing energy metabolism possible. These studies were performed on isolated mitochondria and extrapolation to the in vivo situation is more or less speculative.


Sign in / Sign up

Export Citation Format

Share Document