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952.
The study of chloride‐induced corrosion started more than three decades ago, after extensive cases of damage were observed on reinforced concrete structures in coastal regions and on infrastructural objects exposed to salt action. Nowadays, the basis for sustainable concrete industry lies in these three aspects: reducing CO2 emissions by using by‐products of other industries (slag, fly ash, silica fume) for cement production, conservation of natural resources by replacing part of the aggregate with recycled construction waste, as well as use of recycled water in concrete production, and finally, construction of durable concrete structures. Durability design procedures for reinforced concrete structures in aggressive environments are still to a large extent empirical, especially in the case of using blended cements. The type of cement has a considerable effect on the properties of concrete, especially concrete resistance to the penetration of chloride ions. The paper presents results of testing durability and deformational properties of concrete produced with quaternary‐blended cement. A clearer insight into these properties is a necessary starting point for the performance‐based design of concrete prepared with blended cements, leading to more durable and corrosion‐free concrete structures in aggressive environments. 相似文献
953.
954.
为了解决4.2 m柔掩工钢支架强度有限,在顶板压力大或地质变化时经常造成支架挤架、摞架、架斜等现象给安全生产带来的重大安全隐患。宏远煤矿大胆尝试采用ZRY36/45L型柔性液压支架采煤工艺,结果表明采用该液压支架后保证了工作面的安全生产,生产效率得到了较大的提高,促进了安全高效矿井的建设。 相似文献
955.
《International Journal of Hydrogen Energy》2019,44(48):26213-26225
This work aimed to investigate the effects of supplementing two distinct types of ash, namely fly ash (FA) and bottom ash (BA) on the dark fermentation (DF) process of food waste (FW) for H2 production. Both types of biomass combustion ash (BCA) were collected in an industrial bubbling fluidized bed combustor, using residual forest biomass as fuel. Results indicated that adding BCA at different doses of 1, 2 and 4 g/L could effectively enhance H2 generation when compared to the control test without BCA addition. This stimulatory effect was attributed to the crucial role of metal elements released from BCA such as sodium, potassium, calcium, magnesium, and iron in the provision of buffering capacity and inorganic nutrients for the functioning of hydrogen-forming bacteria. The highest H2 yield of 169 mL per g of volatile solids (VS) were obtained by adding only a small amount of BA (1 g/L) to the reactive system, representing a significant increment of 1070% compared to the control reactor. Furthermore, a significant decrease in the bacterial lag phase time from 26 h to 2.7 h, as well as about a 12-fold increase in the energy recovery as H2 gas was observed at BA dosage of 1 g/L in comparison with the control reactor. Overall, this study suggested that a proper addition of BCA could promote the DF process of FW and enhance biohydrogen production. 相似文献
956.
介绍了唐洞煤矿在缓倾斜炮采工作面应用砌筑矸石墙和留小护巷煤柱2种留巷方式的工程实践,阐述了2种留巷方式的工艺流程和要求,采用极限平衡理论计算得到2244工作面顺槽合理的最小煤柱宽度为2.8m.通过对留巷工艺巷道变形的监测及掘进工期、煤炭回收率的计算分析,结果表明,这2种沿空留巷技术能有效的控制巷道的变形,在矿井生产中能实现减少巷道掘进工程量、缓解采掘接替压力、提高煤炭回收率,取得了显著的技术经济效益;为类似条件的煤矿沿空留巷提供了有益的借鉴. 相似文献
957.
Coal fly ash(CFA)is composed of minerals containing some oxides in crystalline phase(i.e.,quartz and mullite),as well as unburned carbon as mesoporous material,thus enabling CFA to act as a dual-sites adsorbent with unique properties.This work focused on the adsorption of Pb(Ⅱ)and Zn(Ⅱ)from binary system,a mixture containing two metal ion solutions present simultaneously,onto NaOH-modified CFA(MCFA).Several adsorption tests were conducted to evaluate the effect of several parameters,includ-ing pH and contact times.The experiment results indicated that chemical treatment of CFA with NaOH increased pore volume from 0.021 to 0.223 cm3 g-1.In addition,it could also enhance the availability of functional groups on both minerals and unburned carbon,resulting in almost 100%Pb(Ⅱ)and 97%Zn(Ⅱ)adsorbed.The optimum pH for adsorption system was pH=3 and quasi-equilibrium occurred in 240 minutes.Equilibrium data from the experimental results were analyzed using Modified Extended Langmuir(MEL)and Competitive Adsorption Langmuir-Langmuir(CALL)isotherm models.The analysis results showed that the CALL isotherm model could better describe the Pb(Ⅱ)and Zn(Ⅱ)adsorption pro-cess onto MCFA in binary system compared with MEL isotherm model. 相似文献
958.
Greg Perkins Ernest du Toit Greg Cochrane Grant Bollaert 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2016,38(24):3639-3646
Underground coal gasification (UCG) is a process which converts deep, un-mineable or difficult to mine coal resources into syngas which can then be converted into valuable end products such as electric power, liquid fuels, synthetic natural gas and chemicals. This paper provides a summary of the UCG operations conducted at the Chinchilla Demonstration Facility in Australia, focusing on gasifiers constructed using directional drilling. A number of the experiences and key lessons learned from operating multiple underground gasifiers over several years at the facility are described. Implications for the implementation in commercial projects using UCG are also discussed. Finally, the potential of UCG as a method for producing syngas from deep coal is discussed and some of the challenges and opportunities are summarized. 相似文献
959.
企业工会是我们党领导的基层群众组织。从煤矿企业工会的角度,对怎样切实提高其服务职工、管理职工的水平与能力进行了探讨。 相似文献
960.
GSP气化技术煤粉密相输送系统稳定性研究 总被引:2,自引:0,他引:2
为实现大规模工业化GSP气化技术煤粉密相输送系统的稳定输送,研究了煤粉物性、输送工艺、操作参数对输送特性的影响。结果表明:当煤粉湿含量由6.9%降到4.2%时,锁斗下料顺畅,减压系统偶尔出现堵塞。采用压差控制输送煤粉时,煤粉质量流量波动大于20 t/h,而采用流量调节控制煤粉输送时,煤粉质量流量波动小于5 t/h,因此,采用流量调节控制时,煤粉输送稳定性大幅提高。当操作参数进料器流化气量由220~180 m3/h调整为90~140 m3/h时,煤粉输送管线注射器1气体的流量由7 m3/h调整为3 m3/h,投煤后关闭注射器2,可使固气比由280 kg/m3增加到400 kg/m3,质量流量由42 t/h增加到72 t/h,进一步提高了煤粉密相输送系统的稳定性。 相似文献