scholarly journals Characteristics of Pyrolysis and Low Oxygen Combustion of Long Flame Coal and Reburning of Residues

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2944
Author(s):  
Hua Wang ◽  
Wei Zhang ◽  
Haihui Xin ◽  
Deming Wang ◽  
Cuicui Di ◽  
...  

To further understand the problems of coal combustion and coalfield fire reignition, this paper researched the reaction characteristics of coal pyrolysis and low oxygen combustion and the reburning oxidation characteristics of residual structure by thermal analysis methods. The results show that temperature promotes both pyrolysis and low oxygen combustion reactions, but low oxygen combustion reaction is more sensitive to temperature changes. As the constant temperature rises, the mass reduction rate of low oxygen combustion of coal samples reaches 80% on average, which is 4 times that of pyrolysis, and the variations of thermogravimetric parameters are also significantly higher than those of pyrolysis. However, the higher the pyrolysis degree of the residues, the stronger their oxidizability, which greatly enhances the intensity and concentration of the secondary combustion, and the mass of residues is reduced by 90% on average. Conversely, because the combustible components are continuously consumed during low oxygen combustion, the reburning characteristics of residues become less obvious. For instance, the weight loss rate slows down, the burning becomes dispersed, and the burning intensity is weakened. In addition, the heat release is reduced from 8662 to 444.5 J/g, and the change trend is just opposite to that of pyrolysis. The above results show that as the constant temperature rises, the pyrolysis reaction greatly shortens the reburning process, while the low oxygen combustion reaction largely inhibits the reburning.

2011 ◽  
Vol 284-286 ◽  
pp. 1152-1157
Author(s):  
Guo Zhang Tang ◽  
Zhen Gao ◽  
Yan Chang Kong ◽  
Kun Ouyang ◽  
Fu Min Li

The reduction of different basicity BF charge with gases of different H2 ratio has been determined to simulate different BF technology. The results reveal: reduction rate (R & r) and metallization rate of charge increase with the H2 ratio increasing, and the temperature increasing while the reducing time becomes longer simultaneously. The direct reduction degree of charge in Hydrogen-enrichment BF is very low, thus the energy consumption of Ironmaking could be reduced. There is certain difference between metallization rate and reduction degree due to reduction kinetics. The mass loss rate of coke increases sharply with the H2 ratio increasing, the H2 ratio of gas should be selected an appropriate value.


2018 ◽  
Vol 55 (5B) ◽  
pp. 111
Author(s):  
Le Quoc Khanh

          In poor oxygenated environments the oxidation and growth of the living organisms are slowed or stopped, so that food is better preserved. The most appropriate method for oxygen depletion in the air-tight minienvironment is oxygen reduction with iron-based reducing agent, which can reduce the air oxygen concentration to about 0 %, and maintain this low oxygen concentration long during storage. This paper studies the kinetics of oxygen reduction by reducing agent FOCOAR in an airtight minienvironment under isobaric conditions. The kinetics of the reduction process calculated according to the relation vav = [21 % - (end) ] / tend, in which vav is average reduction rate, (end) is oxygen concentration at the end of the experiment, tend is total time needed for the oxygen reduction experiment. Instantaneous reduction rate vred was calculated according to equation vred = ∆/△t, in which ∆is oxygen concentration reduced in time △t, and △t = ti+1 - ti is time interval for oxygen reduction. It is found that vav depends on the quantity of reducing agent FOCOAR, and in certain time interval varies as linear function of reduction time, corresponding to constant vred.  The kinetic result allows an estimating the amount of the reducing agent FOCOAR needed for a preserve minienvironment.


2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Binghong Gao ◽  
Yue Zhang ◽  
Huan Gao

Objective 12 female rowing athletes of Shanghai as research object of this study. 7 weeks of hypoxic experiment will be carried out on the study subjects. Monitoring of HRV and functional indexes of athletes during this period. To explore the effect of 3 weeks of Living High Training High Training Low(HiHiLo) training of female rowers ANS and functional status, and discussion on the relationship between ANS and functional status of athletes in HiHiLo. Methods 12 Shanghai elite female rowers for 3 weeks HiHiLo training. Simulated altitude from 2500m to 3200m, A total of seven weeks of HRV and biochemical function indexes were tested before and after hypoxia training. In addition, the HRV test of the athletes in a hypoxic exposure. According to the change characteristics of each index, analysis of the change of the athletes ANS in acute hypoxic exposure, and the evaluation of the effects of HiHiLo on ANS and functional status. Results 1. The results of HRV test showed that there was no significant difference in time domain and frequency domain between normal condition and low oxygen environment, But SDNN in hypoxia environment in higher than normal environment, RMSSD slightly lower than the normal environment, indicate that hypoxic environment for athletes of cardiovascular ANS regulation will change and PSNS tension decreased; TP decreased and LF/HF increased, but the change was not significant. 2. The detection of the three stages of the athletes found that there were no significant changes in the indicators of HRV. However, the SDNN、RMSSD and PNN50 indexes showed a certain change trend, that settled low oxygen, time domain index increased, and in hypoxia exposure within three weeks are maintained at high levels and hypoxia after the end of each indicator of the level of decline, as well as the domain indexes, the frequency domain indexes HF、LF and LF/HF also showed obvious change tendency. 3. After the beginning of the experiment, Hb、RBC continued to rise, and after three weeks of hypoxia reached the highest value, compared with before the experiment was increased by 7.7%, 5%, RBC and the experiment was significantly different (p<0.05), Hct increased 5.3% after 3 weeks of hypoxia. Hypoxia after the end of the experiment, RBC, Hb and Hct showed a downward trend, at the end of experiment were decreased by 5%, 3.4%, 3.5%(p>0.05); In this experiment, the BU, CK of the Shanghai women`s rowing athletes at each stage in the normal range, there was no significant difference, but there is a clear trend of change; There was no significant difference in the T of the athletes in the seven week test, but the change trend is obvious. The C was significantly decreased (p<0.05) in the second week after hypoxia exposure, and the follow-up period was significantly lower than that before the experiment(p<0.05) at second weeks. T/C value was significantly increased in the second week of hypoxia (p<0.05), the trend of change is roughly the same as T. The correlation analysis between biochemical function index and HRV was found that the correlation coefficient between PNN50 and T/C was 0.672(p<0.05), before hypoxia, LF/HF and T/C were negatively correlated with -0.825(p<0.01), LF/HF and T correlation coefficient -0.789(p<0.01); During the 3 week HiHiLo training, CK was significantly correlated with SDNN, HF and LF, respectively, and the correlation coefficients were -0.425(p<0.05), -0.43(p<0.05), -0.496(p<0.01), LF/HF and T were negatively correlated with -0.42(p<0.05); The tracking period athletes T were significantly positively correlated with SDNN, RMSSD, PNN50, HF in HRV index, correlation coefficients were 0.378(p<0.05), 0.443(p<0.01), 0.341(p<0.05), 0.371(p<0.05). In addition, the correlation coefficient between PNN50 and C was 0.411(p<0.05). Conclusions 1. The ANS of Shanghai female rowers will change in acute hypoxic exposure, SNS would be enhanced. 2. Three weeks of longer periods of hypoxia training will enable the athletes to enhance the PSNS activity of the ANS, and may make the ability of the regulating equilibrium state from SNS and PSNS, the changes of the ANS regulation of the athletes to the PSNS activity were enhanced, this may be the result of long time hypoxia stimulation and training, to a certain extent, it shows that the level of athletes` performance has been enhanced. 3. Functional status index of Shanghai women`s rowing athletes was well in 3 week HiHiLo training, Part of the improvement of the functional status indicators shows that the effect of the hypoxic training is obvious, The functional status of athletes showed a rising trend.   4. In the different stages of the experiment, there was a significant correlation between the HRV partial indexes and some biochemical indexes. This shows that there is a certain relationship between the ANS and functional status in the hypoxic training. Detection and evaluation of autonomic nervous function in hypoxic training can reflect the functional level of the body to a certain extent. This suggests that it is necessary to strengthen the research and application of ANS function evaluation in hypoxic training.


1958 ◽  
Vol 195 (3) ◽  
pp. 726-734 ◽  
Author(s):  
Roy B. Mefferd ◽  
Henry B. Hale

The responses of acclimated rats (heat, 35°C; neutral, 24°C; or cold, 3°C) to abrupt temperature changes (24-hr. exposure with fasting) are compared. Variables studied include weight loss, rate of fasting weight loss regain, water intake, urine volume, urinary Na, K, Ca, Mg, PO4, urea, uric acid, creatinine, creatine, taurine, ß-alanine, glycine, α-alanine, valine + methionine, serine, threonine, tyrosine, glutamic acid, aspartic acid, lysine, arginine and histidine. As compared to the neutral controls, most of the variables of the heat- and cold-acclimated rats were different under all conditions tested. Despite adaptive changes induced by the prior treatments, however, the changes directly attributable to abrupt environmental shifts were somewhat similar for the majority of the variables to those of the controls. Other variables in the cold-acclimated group tended toward nonresponsiveness, while the the heat-acclimated group tended toward overresponsiveness. Return to the neutral environment did not always result in a normalization, though the tendency was often in this direction.


Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 839
Author(s):  
Gi-Ho La ◽  
Joon-Sung Choi ◽  
Dong-Joon Min

The reaction behaviour of partially reduced iron (PRI) was studied to understand the effect of PRI utilisation in the blast furnace process. For quantitative analysis, the reaction behaviour of PRI under typical operating conditions of a blast furnace was measured using the thermogravimetric method along with the reduction behaviour of hematite and sinter. Experimental results indicated that the reoxidation behaviour of the PRI under the conditions of the upper shaft of the blast furnace retarded the indirect reduction rate in the lower shaft. The rate constants derived from the grain model, experimental results of scanning electron microscopy, and porosimetry analysis indicated that the phenomenon of reduction retardation of PRI under the conditions of the lower shaft originated owing to the reoxidation of PRI, resulting in the blockage of pores. The reaction behaviour considering the reaction characteristics of PRI was derived under conventional blast furnace conditions.


2021 ◽  
Vol 251 ◽  
pp. 02051
Author(s):  
Sang Un Ahn ◽  
Jeongheon Kim ◽  
Heejune Han ◽  
Seung Hee Lee ◽  
Heejun Yoon

We proposed a disk-based custodial storage as an alternative to tape for the ALICE experiment at CERN to preserve its raw data. The proposed storage system relies on Redundant Array of Independent Nodes (RAIN) layout – the implementation of erasure coding in the EOS storage suite, which is developed by CERN – for data protection and takes full advantage of high-density Just-Bunch-Of-Disks (JBOD) enclosures to maximize storage capacity as well as to achieve cost-effectiveness comparable to tape. The system we present provides 18 PB of total raw capacity from the 18 set of high-density JBOD enclosures attached to 9 EOS front-end servers. In order to balance between usable space and data protection, the system will stripe a file into 16 chunks on the 4-parity enabled RAIN layout configured on top of 18 containerized EOS FSTs. Although the reduction rate of available space increases up to 33:3% with this layout, the estimated annual data loss rate drops down to 8:6 × 10−5%. In this paper, we discuss the system architecture of the disk-based custodial storage, 4-parity RAIN layout, deployment automation, and the integration to the ALICE experiment in detail.


2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Yingjun Jiang ◽  
Jiangtao Fan ◽  
Pengyu Lv ◽  
Kejia Yuan ◽  
Yong Yi ◽  
...  

In this paper, based on the thermosetting properties, bonding performance, high-temperature water damage resistance, and aging resistance properties of epoxy-emulsified asphalt, the best formulation of epoxy emulsified asphalt as a skid resistance fog sealing asphalt is studied. Through accelerated wheel wear and other tests, the effects of the ratio of the amount of skid resistance particles to the amount of epoxy emulsified asphalt, the total amount of skid resistance fog seal asphalt, and the construction process on the skid resistance durability of the skid resistance fog seal were studied. The results show that the epoxy emulsified asphalt formula code A80 (E2) (emulsified asphalt : water-based epoxy = 80 : 20) is the best formula; when the proportion of emery and epoxy emulsified asphalt is 1 : 1, the British Pendulum Number (BPN) reduction rate of the skid resistance fog seal-test piece worn 100,000 times was 27.4%. Compared with the same period, the reduction rate was reduced by 4.6% on average, with the smallest mass loss rate and the best skid resistance durability. When the total amount of skid resistance fog seal asphalt is 1.2 kg/m2, the BPN reduction rate of the skid resistance fog seal specimen worn 100,000 times was 27.4%, which is an average reduction of 5.8% over the same period, and the mass loss rate is the smallest, and the skid resistance durability optimal. When using the premixed process, the BPN of the specimen was reduced by 13.2% after abrasion of 100,000 times. Compared with the “one asphalt and one sand” and “double asphalt and one sand” molded specimens, the mass loss rate was reduced by 15.0%, 4eU&7.2%, showing the best skid resistance performance. The results can provide guidance for the design and construction of AC-13 and other pavement skid resistance fog seals.


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