A Evaluation on Pulverized Coal Combustion Properties Using a Thermogravimetric Analyze Method

2013 ◽  
Vol 423-426 ◽  
pp. 609-613 ◽  
Author(s):  
Yan Hong Gao ◽  
Ling Tao Bian

In the present research work, volatile matter, influences of reaction temperature and particle size on combustion performance were investigated. Important results were obtained by experimental researches. Ignition point of anthracite coal/bituminous coal blends decreased with volatile matter in blend and combustion was improved. Burnout of coal blends decreased as a function of particle size. However, similar effects were gained when particle size less than 0.074mm accounted for 70%, 60% and 50%, respectively. By contrast, the ratio of 50% was a better choice for good effect and low cost.

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Muhammad Ariff Hanaffi Mohd Fuad ◽  
Eljoji J. A. Loijon ◽  
Mohd Faizal Hasan ◽  
Mohd Rosdzimin Abdul Rahman ◽  
Bemgba B. Nyakuma ◽  
...  

This study aimed to investigate the effect of batches (1, 2 and 3), particle sizes (<250 µm, range of 300 µm to 500 µm), and sections (bottom, middle and top) on combustion performance of the oil palm frond (OPF) petiole after torrefaction at 275 °C. The higher heating value (HHV), mass yield, energy yield, HHV yield and proximate analyses of the untorrefied and torrefied OPF petiole for all cases were determined.  The comparison between the untorrefied and torrefied OPF petiole as well as an international benchmark was also performed. In this study, the highest HHV of the torrefied OPF petiole (22.85±0.07MJ/kg) was obtained at the bottom section with the particle size of < 250 µm.  Furthermore, the fixed carbon content of the torrefied OPF petiole increased, whereas the volatile matter, moisture content, mass and energy yields decreased for all cases after torrefaction.  HHV yield of OPF petiole was recorded up to 141% after torrefaction.  The ash content was sufficiently satisfied the international benchmark for most cases, except for top section (300-500µm).  The changes in combustion properties of the torrefied OPF petiole for all cases were found to be insignificant whereas significant improvement could be observed when compared to untorrefied OPF petiole.  Overall, the study revealed that the appropriate particle size for torrefaction can promote it to be a vital source for energy production from oil palm biomass.


2011 ◽  
Vol 361-363 ◽  
pp. 882-886
Author(s):  
Ming Yan Gu ◽  
Xu Hui Liu ◽  
Biao Ma ◽  
Jia Xin Li

In this study, the combustion behaviors of three kinds of coal and their mixtures under the pure oxygen and air atmosphere were studied by using a thermo-gravimetric analyzer. The combustion characteristics such as ignition and burnout behavior were investigated in the temperature from 20°C to 800°C. The influence of mixing Shenhua coal with Huaibei bituminous and Sanming anthracite coal on combustion characteristics was conduced. The results obtained show that pure oxygen content accelerated the coal burning process greatly; the coal volatile matter started to release at a lower temperature and the coal burning process was finished earlier compared with the burning process under the air atmosphere. The addition of Shenhua coal improved the combustion characteristics of both Huaibei bituminous coal and Sanming anthracite in a different way. For the Huaibei bituminous coal, both the ignition and burnout temperature decreased linearly with the increasing ratio of Shenhua coal; while for the Sanming anthracite, the addition of Shenhua coal greatly lowered the mixture ignition temperature, and the burnout temperature was nearly the same. The activation energy of the mixture coal with Shenhua and Huaibei coal reduced with the ratio of Shenhua coal. For the Shenhua and Sanming coal mixture, the activation energy changed differently at the two burning stages.


Author(s):  
Anjali Pandya ◽  
Rajani Athawale ◽  
Durga Puro ◽  
Geeta Bhagwat

Background: The research work involves development of PLGA biodegradable microspheres loaded with dexamethasome for intraocular delivery. Objective: To design and evaluate long acting PLGA microspheres for ocular delivery of dexamethasone. Method: Present formulation involves the development of long acting dexamethasone loaded microspheres composed of a biodegradable controlled release polymer, Poly(D, L- lactide-co-glycolide) (PLGA), for the treatment of posterior segment eye disorders intravitreally. PLGA with monomer ratio of 50:50 of lactic acid to glycolic acid was used to achieve a drug release up to 45 days. Quality by Design approach was utilized for designing the experiments. Single emulsion solvent evaporation technique along with high pressure homogenization was used to facilitate formation of microspheres. Results: Particle size evaluation, drug content and drug entrapment efficiency were determined for the microspheres. Particle size and morphology was observed using Field Emission Gun-Scanning Electron Microscopy (FEG-SEM) and microspheres were in the size range of 1-5 μm. Assessment of drug release was done using in vitro studies and transretinal permeation was observed by ex vivo studies using goat retinal tissues. Conclusion: Considering the dire need for prolonged therapeutic effect in diseases of the posterior eye, an intravitreal long acting formulation was designed. Use of biodegradable polymer with biocompatible degradation products was a rational approach to achieve this aim. Outcome from present research shows that developed microspheres would provide a long acting drug profile and reduce the frequency of administration thereby improving patient compliance.


2021 ◽  
Vol 7 (2) ◽  
pp. 41
Author(s):  
Farzaneh Farivar ◽  
Pei Lay Yap ◽  
Ramesh Udayashankar Karunagaran ◽  
Dusan Losic

Thermogravimetric analysis (TGA) has been recognized as a simple and reliable analytical tool for characterization of industrially manufactured graphene powders. Thermal properties of graphene are dependent on many parameters such as particle size, number of layers, defects and presence of oxygen groups to improve the reliability of this method for quality control of graphene materials, therefore it is important to explore the influence of these parameters. This paper presents a comprehensive TGA study to determine the influence of different particle size of the three key materials including graphene, graphene oxide and graphite on their thermal parameters such as carbon decomposition range and its temperature of maximum mass change rate (Tmax). Results showed that Tmax values derived from the TGA-DTG carbon combustion peaks of these materials increasing from GO (558–616 °C), to graphene (659–713 °C) and followed by graphite (841–949 °C) The Tmax values derived from their respective DTG carbon combustion peaks increased as their particle size increased (28.6–120.2 µm for GO, 7.6–73.4 for graphene and 24.2–148.8 µm for graphite). The linear relationship between the Tmax values and the particle size of graphene and their key impurities (graphite and GO) confirmed in this study endows the use of TGA technique with more confidence to evaluate bulk graphene-related materials (GRMs) at low-cost, rapid, reliable and simple diagnostic tool for improved quality control of industrially manufactured GRMs including detection of “fake” graphene.


2012 ◽  
Vol 433-440 ◽  
pp. 5611-5615
Author(s):  
Jian Sheng Hu

Aimed at the problem of the embedded multi-channel video acquisition and display system, a new one based on FPGA is put forward. The configuration of the system is given. The principle and key issue is analyzed. Using of the state shift mechanism, t the controlling time sequence signals of TFT-LCD are produced; The synchronization among multi-channel video acquisition is realized by using time-division multiplexing technology; The problem of conflict between reading and writing frame cache is solved through the two SRAM switch; The frames composition technology is applied to accomplish the change from interlaced scanning to progressive scanning. The result of project application shows the virtues of system, such as good effect of acquisition and display, low cost and low power consumption.


2021 ◽  
Vol 02 (01) ◽  
Author(s):  
Siti Khadijah Hubadillah ◽  
◽  
Norsiah Hami ◽  
Nurul Azita Salleh ◽  
Mohd Riduan Jamalludin ◽  
...  

The purpose of this work is to study the effect of kaolin particle size for the preparation of low cost ceramic membrane suspension and ceramic membrane structure. Kaolin particle size is categorized into two categories; i) ≤ 1µm and ii) ≥ 1 µm. The suspension is prepared via stirring technique under 1000 rpm at 60°C. The particle size of kaolin is characterized using field emission scanning electron microscope (FESEM) and the prepared suspension is characterized in term of its viscosity. Results indicate that the particle size gave significant effect to the viscosity of ceramic membrane suspension. Preliminary data showed that kaolin with particle size ≤ 1µm resulted ceramic membrane with dense structure.


Gefahrstoffe ◽  
2019 ◽  
Vol 79 (11-12) ◽  
pp. 443-450
Author(s):  
P. Bächler ◽  
J. Meyer ◽  
A. Dittler

The reduction of fine dust emissions with pulse-jet cleaned filters plays an important role in industrial gas cleaning to meet emission standards and protect the environment. The dust emission of technical facilities is typically measured “end of pipe”, so that no information about the local emission contribution of individual filter elements exists. Cheap and compact low-cost sensors for the detection of particulate matter (PM) concentrations, which have been prominently applied for immission monitoring in recent years have the potential for emission measurement of filters to improve process monitoring. This publication discusses the suitability of a low-cost PM-sensor, the model SPS30 from the manufacturer Sensirion, in terms of the potential for particle emission measurement of surface filters in a filter test rig based on DIN ISO 11057. A Promo® 2000 in combination with a Welas® 2100 sensor serves as the optical reference device for the evaluation of the detected PM2.5 concentration and particle size distribution of the emission measured by the low-cost sensor. The Sensirion sensor shows qualitatively similar results of the detected PM2.5 emission as the low-cost sensor SDS011 from the manufacturer Nova Fitness, which was investigated by Schwarz et al. in a former study. The typical emission peak after jet-pulse cleaning of the filter, due to the penetration of particles through the filter medium, is detected during Δp-controlled operation. The particle size distribution calculated from the size resolved number concentrations of the low-cost sensor yields a distinct distribution for three different employed filter media and qualitatively fits the size distribution detected by the Palas® reference. The emission of these three different types of filter media can be distinguished clearly by the measured PM2.5 concentration and the emitted mass per cycle and filter area, demonstrating the potential for PM emission monitoring by the low-cost PM-sensor. During the period of Δt-controlled filter aging, a decreasing emission, caused by an increasing amount of stored particles in the filter medium, is detected. Due to the reduced particle emission after filter aging, the specified maximum concentration of the low-cost sensor is not exceeded so that coincidence is unlikely to affect the measurement results of the sensor for all but the very first stage of filter life.


2021 ◽  
Vol 13 (4) ◽  
pp. 656-661
Author(s):  
Yiyan Lv ◽  
Qiwei Zhan ◽  
Xiaoniu Yu

Microbial-induced degradation of aromatic organic compounds and mineralization of zinc ions have attracted much attention because of its low cost, simple operation and quick response. This research, toluene was decomposed and made the concentration of carbonate ions increased accordingly by the enzymatic pressing of microorganisms, meanwhile carbonate ions mineralized zinc ions into carbonate precipitations. The composition and microstructure were analyzed systematically. The analysis results indicated that carbonate precipitations, basic zinc carbonate, could be successfully prepared by microbial method. The particle size of basic zinc carbonate was nanometer, and its shape was near-spherical. Furthermore, the phase composition, functional groups and surface morphology of the precipitations prepared by different methods were basically the same. This work provided a new method for remediation of zinc ion pollution based on the degradation of toluene.


Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 712
Author(s):  
Alvaro Aracena ◽  
Andrés Valencia ◽  
Oscar Jerez

In pyrometallurgical processes refining copper, the main source of loss in the conversion stage is from slag. This paper reports on research work treating converter slag containing high percentages of copper (36 wt%) using ammonium hydroxide at room temperature. Variables analyzed are solution pH, agitation, temperature, NH4OH concentration and particle size. Results showed that the hydronium ion resulting from ammonium hydroxide dissociation was the main oxidant of copper compounds in slag, such as CuO, Cu2O and Cu, with the exception of CuFeO2. The particles contain a large amount of microcracks (porosity) in their refractory structure (analyzed by compositional image capture (BSE)). Thus, the diffusion of the leaching solution through the microcracks making contact with the copper oxides would be allowed. Leaching mechanisms were corroborated by X-ray diffraction and scanning electron microscopy analysis. Increasing temperature and NH4OH concentration while decreasing particle size obtained higher copper recoveries, reaching values of 84.8%. Under the same conditions, the main impurity (iron) was minimal (<2%). Solution pH also affected slag leaching. Agitation of the solution positively affected the rate of copper extraction. Leaching kinetics of the leaching solution through the porosity formed in the slag was analyzed under the intraparticle diffusion model. The reaction order was 1.2 with respect to the concentration of ammonium hydroxide and the model was inversely proportional to the square of the particle radius. The activation energy obtained was 42.3 kJ/mol for temperature range 283 to 333 K.


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