LIU Zheng-jian
,
REN Shan
,
ZHANG Jian-liang
,
LIU Wei-jian
,
XING Xiang-dong
,
SU Bu-xin
钢铁研究学报(英文版)
In order to effectively recycle resource for the benefit of the global environment, the utilization of waste plastics as auxiliary injectant for blast furnaces is becoming increasingly important. Combustion kinetics of plastics-coal blends with 0, 10%, 20% and 40% waste plastics (WP) are investigated separately by thermogravimetric analysis (TGA) from ambient temperature to 900 ℃ in air atmosphere. These blends are combusted at the heating rates of 5, 10 and 20 ℃/min. The results indicate that, with the increase of waste plastics content, the combustion processes of blends could be divided into one stage, two stages and three stages. The waste plastics content and heating rates have important effects on the main combustion processes of blends. With the increase of waste plastics content, the ignition temperature and the final combustion temperature of blends tend to decrease, while the combustion reaction becomes fiercer. With the increase of the heating rate, the ignition temperature, the mass loss rate of the peaks and the final combustion temperature of blends combustion tend to increase. The Flynn-Wall-Ozawa (FWO) iso-conversional method is used for the kinetic analysis of the main combustion process. The results indicate that, when the waste plastics content varied from 0 to 40%, the values of activation energy increase from 126.05 to 184.12 kJ /mol.
关键词:
waste plastics
,
anthracite
,
co-combustion kinetics
,
TGA
,
iso-conversional method
JIANG Hai-bing
,
ZHANG Jian-liang
,
FU Jian-xun
,
CHANG Jian
,
LI Jing
钢铁研究学报(英文版)
The properties of mixed coals were studied on the basis of known various properties of the injecting coals in the treatise. The structure of the injecting coals was optimized and put into practical application. It was found that the ignition point was lowered with mixed coals, however, both combustibility and grindability were improved, and explosibility of the mixed coals were decreased as well. Hence, mixed coals injection not only can improve the amount of the injecting coals greatly, but also improve the economical and technical indexes of the blast furnace.
关键词:
blast furnace
,
pulverized coal
,
property
,
injection
QI Cheng-lin
,
ZHANG Jian-liang
,
LIN Xiang-hai
,
LIU Qin-yuan
,
WANG Xiao-liu
钢铁研究学报(英文版)
The combustion process of pulverized coal was investigated by non-isothermic integral thermogravimetry. The thermogravimetry curves were fitted by the Coats-Redferm approximation function, and kinetic parameters and characteristic temperatures were obtained. The optimal mixing ratio and particle size can be ascertained. The characteristic temperature of pulverized coal can be obtained from the thermogravimetry curve, and the combustion of coal can be divided into homogeneous and heterogeneous combustion according to the differential thermal analysis curve. The activation energy of a single type of coal ranking from low to high is as follows: bituminous coal, meager-lean coal, and anthracite. In the first mixing method, with more low-price meager-lean coal B replacing high-price anthracite A, the activation energy slightly decreases; with more bituminous coal replacing meager-lean coal, total tendency makes a declining of activation. In the later mixing method, with an increase in particle size, a declining activation energy can be seen in total tendency.
关键词:
pulverized coal combustion
,
themogravimetry
,
kinetics
,
mixed-coal granularity
,
coal combustion
ZHANG Jian-liang
,
CHEN Yong-xing
,
FAN Zheng-yun
,
HU Zheng-wen
,
YANG Tian-jun
,
Tatsuro Ariyama
钢铁研究学报(英文版)
The objective of the present investigation is to analyze the influence of profile of blast furnace on the burden motion and stress field through 3D-DEM (three-dimensional discrete element method). It is clarified that the decrease of shaft angle speeds up the velocity of burden descending and decreases normal stress between particles or particle and wall. This change is good for the smooth operation of blast furnace. However, ore and coke would be mixed for the too small shaft angle (75°), which would influence the permeability in blast furnace. Thus, the appropriate shaft angle is around 80°. Decrease of bosh angle prevents the burden descending motion and increases normal stress between particles and bosh wall. Meanwhile, maximum normal stress acting on the wall moves from belly wall to bosh wall in the case of 68° bosh angle, which accelerates abrasion of refractory in bosh by friction force between particles and wall. Although burden descends smoothly in the case of 88° bosh angle, room is not enough for the ascending heated gas flow. Thus, the appropriate bosh angle is about 78°.
关键词:
blast furnace
,
profile
,
solid motion
,
stress
,
discrete element method
ZHANG Xu
,
ZHANG Jian-liang
,
HU Zheng-wen
,
et al
钢铁研究学报(英文版)
On the premise of maintaining the reducibility of sinter unchanged, it is of great significance to reduce the RDI of sinter, which will improve the permeability of blast furnace burden column, so as to realize stable and smooth performance, and keep high yield and low consumption. Under laboratory conditions, a study was proposed on the RDI and RI of sinter, which was immersed with different types and concentrations of solutions. The results show that Cl- is the main factor for reducing the RDI of sinter, and the RDI and RI of sinter decrease with the increase of Cl- concentration. With comprehensive consideration of the RDI and RI of sinter, when the concentration of Cl- is 2%, the RDI of sinter will be significantly reduced and RI will not be affected. In order to study the mechanism of CaCl2 effect on the RDI and RI of sinter, analysis based on the methods of IR Spectra, SEM and chalcography was adopted.
关键词:
sinter;CaCl2;RDI (Reduction Degradation Index);RI(Reduction Index)
WANG Yi-ci
,
ZHANG Jian-liang
,
ZHANG Fang
,
LUO Guo-ping
钢铁研究学报(英文版)
Influence of sintering temperature, basicity and MgO content on the formation characteristics of calcium ferrite in low silicon sinter of Baotou Iron and Steel Company was studied by means of mini-sintering test and mineralographic microscope analysis. In addition, the suitable sintering parameters such as temperature and basicity were explored. The results found that optimum temperature for the formation of calcium ferrite is 1280 ℃, the basicity of 25-28 is helpful to the development of acicular or columnar calcium ferrite, and MgO content in the low silicon sintering raw materials should be lower than 28% because MgO can intensively inhibit the formation of calcium ferrite. And calcium ferrite in the sinter belongs to calcium ferrite with low calcium, which is different from that in ordinary sinter at home and abroad. So, it provided theoretical basis for promoting formation of calcium ferrite in low silicon sinter and improving properties of sinter.
关键词:
low silicon sinter
,
formation characteristics
,
calcium ferrite
,
sintering temperature
,
basicity
ZHANG Jian-liang
,
REN Shan
,
SU Bu-xin
,
LIN Yin-he
,
LONG Shi-gang
钢铁研究学报(英文版)
In order to study the combustion characteristics of waste tire particle (WTP), pulverized coal (PC) and their mixture, the contents of CO, CO2 and O2 of off-gas during the combustion of WTP, PC and mixture under the condition of rich oxygen by 0-4% in blast and at 1250 ℃ were measured simultaneously using synthetically infrared analyzer, and then the corresponding combustion ratio was calculated and compared. The results showed that the burning rate of WTP reached approximately 57%, which is much higher than that of PC (only about 18%) in the initial 650 s in fresh air, and then the increase of combustion rate of PC is faster than that of WTP; the combustion rate of PC improved remarkably with the addition of WTP. Meanwhile, the combustion rates of all these materials improved with the increase of oxygen content.
关键词:
blast furnace
,
waste tire particle
,
pulverized coal
,
combustion ratio
