The test research on partial relieving pressure for the entry in the deep mine under high stress and friable surrounding rock

Based on the geological condition of Zhangxiaolou deep mine in Xuzhou mining area, under 986 m in depth, 20.6-31.6 MPa in maximum horizontal principal stress, and friable and fractured surrounding rock, test researches on partial relieving pressure were completed for the entry with U-steel arched yielding support. The relieving pressure parameters, technology process and results of springing blasting by boreholes and excavating pockets in the two sides of entry were introduced. It is demonstrated that springing will not be shaped under the condition of single borehole arrangement after exploded, the arrangement by a group, it will make borehole bottom form springing in 0.6-0.8 m in diameter, that convergence of two sides and roof to floor have some increments by using springing blasting for reliving pressure. This kind of method for reliving pressure is not suitable to use in the deep mine, and that the convergence of two sides obviously declined by excavating pocket in two sides, it can be still used in the entry with metal support, while maintenance of entry in deep mines is difficult, and can not be supported by bolt or bolt with wire mesh.

Heat treatment and granule medium internal highpressure forming of AA6061 tube

The new forming process of AA6061 alloy tube, including solution treatment, granule medium internal high-pressure forming and aging treatment, was developed. The AA6061 alloy tube via heat treatment satisfied the forming requirement, and the granule medium internal high pressure forming method for AA6061 alloy tube was also realized by using convenient implementation with low requirement of equipment and flexible design of product. At a solution temperature of 560℃ and time of 120 min, the elongation of the AA6061 extruded tube increases by 300% and the strength and the hardness dramatically decrease too. Therefore, the AA6061 alloy tube meets the requirement of internal high-pressure forming because of the improvement of formability. The experiments shows that the strength and hardness of AA6061 alloy workpiece recover to that of the as-received alloy at an aging temperature of 180℃ and time of 360 min, and the strength of AA6061 alloy workpiece is equal to the base alloy. The typical parts of convex ring tube, stepped shaft tube and hexagonal tube were successfully produced in lab by using the present forming method. The forming tests show that the maximum expansion ratio(MER) of the AA6061 extruded tube increases by 25.5% and the material properties of formed AA6061 alloy tube reached the performance of as-received alloy.

Effects of Combined Instantaneous High-Pressure and Medium Temperature on Peroxidase Activity in Wax Gourd Juices

Based on the instantaneous pressurization and depressurization produced by high pressure single pole cylinder pump and valve, the effects of the continuous processing on the peroxidase (POD) activity in wax gourd juices were investigated. Results showed that the processing factors such as pressure, temperature, pH and processing time are important to the POD activity. POD in crude juices could be inactivated apparently above 50 MPa(pH 4.6, 35℃, 4 min), and activated at 20 MPa ( P < 0.01). Its remarkable inactivation could also be observed at 45 and 55℃ (20 MPa, pH 4.6, 4 min), and the evident activation appears at the material temperature 35℃ ( P < 0.01). The pH 3.0 could destroy POD almost completely (20 MPa, 35℃, 4 min), while pH 6.0 could not influence apparently the POD activity in crude juices( P > 0.05). In addition, the rules of POD activity along with the treatment time are variational under different processing pressures. The higher the treating pressure is, the shorter the processing time is needed to inactivate POD.

Effects of Combined Instantaneous High-Pressure and MediumTemperature on the Retention of Total Vitamin Cin Wax Gourd Juices

Based on the instantaneous high-pressure(IHP)produced by high-pressure single pole-cylinder pump, the effects of combining this pressure with medium temperature on the retention of total vitamin C(Vc)in wax gourd juices were investigated under 20 - 80 MPa, 35 - 58℃, pH 3. 0 - 6. 0 and processing time 0-8 min. Results showed that the loss of Vc increased with elevated processing temperatures(50 MPa, 4 min). When the temperature of raw juices was 35℃, the retention of total Vc was higher under 40 - 60 MPa than that under the pressure < 40 MPa or > 60 MPa, and it was up to 94%(4 min). The retention of total Vc decreases slowly within 6 min, but rapidly after 6 min. The pH can also influence the retention of total Vc, and this retention can come to a highest point at pH 6.0.

WUGONG MTS.REGION AS A CALEDONIAN MEDIUM-HIGH PRESSURE METAMORPHIC BELT:EVIDENCE FROM b_0 VALUES OF WHITE MICAS

The Wugong Mts. region may have experienced three stages of metamorphism in Early Paleo-zoic, which may be closely related to the generations of regional deformation. The first stage ismedium-pressure metamorphism, the second medium- and high-pressure one with stress on high-pressure metamorphism, and the third low-pressure and high-temperature metamorphism. Theregion, as a whole, is a Caledonian medium-high pressure metamorphic belt.

Study of dynamic pressure roadway supporting scheme under condi- tion of thick composite roof

This paper analyzed the strata behaviors of solid-coal roadway, gob-side entry driving and deformation law of surrounding rock in depth under high stress and thick composite roof based on the dynamic pressure roadway as engineering background in Fengcheng mining area, Jiangxi province. The results, both field measurement and numerical simulation show that gob-side entry driving results the deformation of coal roadway main wall, however, entity-coal roadway driving results deformation of main roof and floor. The maintenance state of gob-side entry driving is better than entity-coal roadway, this situation is relevant to thick composite roof layered and easy collapse characteristics. At the same time, this paper put fox＇ward and proved proper dynamic pressure roadway supporting scheme under the surrounding rock condition and stress environment.

The Influence of the Imperfectness of Contact Conditions on the Critical Velocity of the Moving Load Acting in the Interior of the Cylinder Surrounded with Elastic Medium

The dynamics of the moving-with-constant-velocity internal pressure acting on the inner surface of the hollow circular cylinder surrounded by an infinite elastic medium is studied within the scope of the piecewise homogeneous body model by employing the exact field equations of the linear theory of elastodynamics.It is assumed that the internal pressure is point-located with respect to the cylinder axis and is axisymmetric in the circumferential direction.Moreover,it is assumed that shear-spring type imperfect contact conditions on the interface between the cylinder and surrounding elastic medium are satisfied.The focus is on the influence of the mentioned imperfectness on the critical velocity of the moving load and this is the main contribution and difference of the present paper the related other ones.The other difference of the present work from the related other ones is the study of the response of the interface stresses to the load moving velocity,distribution of these stresses with respect to the axial coordinates and to the time.At the same time,the present work contains detail analyses of the influence of problem parameters such as the ratio of modulus of elasticity,the ratio of the cylinder thickness to the cylinder radius,and the shear-spring type parameter which characterizes the degree of the contact imperfection on the values of the critical velocity and stress distribution.Corresponding numerical results are presented and discussed.In particular,it is established that the values of the critical velocity of the moving pressure decrease with the external radius of the cylinder under constant thickness of that.

深埋综放工作面顺槽围岩动力破坏机理及其支护技术

为探究西部深埋综放工作面围岩动力破坏机理,提出了高强度锚索支护与围岩卸压协同作用的支护方案,完成了5×10^(5)J冲击能量下、不同卸压技术围岩动力破坏计算机仿真分析,确定了工作面顺槽卸压参数,制定了围岩变形规律监测方案并完成了实测工作。数值模拟表明:锚索由原设计φ21.6 mm×8200 mm提高至φ28.6 mm×8200 mm,顶板锚索数量由原7根减少至5根;冲击能量为5×10^(5)J时,顺槽的部分锚杆被拉断,巷道发生失稳破坏,围岩进行卸压后,顶板应力减小15.03%,帮部应力减小6.61%;顶板位移减小31.23%,帮部位移减小38%;地面水平井压裂深度为20~30 m,顺槽围岩应力和围岩变形下降较快,应力下降率降幅明显。实测结果表明:高强度锚索与围岩卸压协同作用,可以有效控制围岩变形。

高瓦斯中硬煤层超高压水力割缝卸压增透技术及应用

为了提高高瓦斯中硬煤层卸压增透及瓦斯抽采效果,研究了顺层长钻孔超高压水力割缝技术,分析了其卸压增透机理,开展了超高压水力割缝现场试验,确定了等效割缝半径和有效瓦斯抽采半径,考察了超高压水力割缝技术的应用效果。研究结果表明:超高压水力割缝技术具有切割速度快、切割半径大等特点,相当于在钻孔周围煤体开采极薄保护层,平均单刀割缝时间9 min,单刀出煤量0.32~0.42 t,等效割缝半径为1.55~1.78 m;超高压水力割缝组单孔平均抽采浓度76.5%,单孔平均抽采纯量为0.089 m^(3)/min,分别是普通钻孔的4.58倍和4.05倍,是水力冲孔的1.2倍和1.43倍,可见该技术可以大幅度提高卸压增透及瓦斯抽采效果。

煤电机组热电解耦技术路线对比

旨在深入探讨火电厂热电解耦的多种技术路线,包括切除低压缸供热技术、旁路联合供热技术、高压电极锅炉技术和熔盐蓄热高能级工业供汽技术。通过对比分析各种技术的原理、应用场景、技术关键点及优缺点,旨在找到适合不同场景的最佳热电解耦方案。研究方法主要包括文献调研、技术分析及案例研究。研究结果表明,这几种技术路线各有优劣,需根据电厂的实际情况和调峰需求进行选择。切除低压缸供热技术适用于低负荷下供热需求较小的场景;旁路联合供热技术具有较强的热电解耦能力,但热经济性较差;高压电极锅炉技术虽投资成本较高,但能实现快速响应和高效节能;熔盐蓄热高能级工业供汽技术则适用于产生高品质蒸汽的场景。

变几何涡轮燃气轮机总体性能研究

为深入了解变几何涡轮对燃气轮机的总体性能影响机理,通过部件法对燃气轮机进行建模,然后分别改变高压涡轮、中压涡轮和动力涡轮的第一级导向器喉道面积,在不考虑导叶两端调节机构和导叶间隙等对涡轮效率影响情况下,对燃气轮机总体性能的变化情况进行了系统地分析,并得出各截面的总温与总压变化情况。结果表明:在采用保持高压涡轮入口总温恒定的控制规律时,增大燃气轮机的高压涡轮流通能力,燃气轮机输出轴功率与耗油率均不断增加,高压涡轮流通能力增加10%,输出轴功率与耗油率分别上升2.83%与1.13%;增大燃气轮机的中压涡轮流通能力,导致燃气轮机输出轴功率降低,耗油率上升,中压涡轮流通能力增加10%,输出轴功率降低9.96%,耗油率上升3.63%;动力涡轮流通能力增加,燃气轮机输出轴功率先上升,后有小幅下降,耗油率增大,动力涡轮流通能力变化量从0增加到10%,输出轴功率降低0.05%,耗油率增加2.01%。

高温中压长输蒸汽管道的热补偿方式及支架约束

高温中压长输蒸汽管道热补偿方式有别于电厂内部短距离输送管道,既要考虑安全性,又要考虑项目的经济性。论文对比常用热补偿方式的优缺点,提出高温中压长输蒸汽管道采用旋转补偿器补偿为主、自然补偿为辅的热补偿方式较为合理。对直线线路段、平行线路段、转角及转角叠加标高微调段、直线高差段、直线跨越段这几种常见的管道布置形式,通过START应力计算软件建模分析,确定较优的热补偿方式及支架约束条件。

长城六矿中硬顶板倾斜工作面切顶留巷关键参数研究

针对长城六矿1301S工作面沿空巷道围岩破坏失稳控制难题,首先,采用UDEC数值模拟方法揭示了1301S工作面侧向覆岩破断运动规律,发现侧向覆岩破断位置均位于巷道上方,且直接顶悬臂结构长度约为1.8m;其次,通过构建侧向覆岩结构力学模型,获得了切顶前后实体煤和矸石支撑体支承应力解析表达式,根据表达式进行算例分析得到切顶前后实体煤支承应力保持不变,均为1.27MPa,靠近巷道左侧矸石支撑体支承应力降低了56.89%;再次,通过理论计算确定了巷旁切顶参数,即切顶高度11m、切顶角度20°、切缝孔间距500mm;最后,设计了1301S工作面运输顺槽切顶留巷技术方案并开展了工业性试验。研究结果表明:切顶后巷道顶底板移近量和两帮移近量分别为1240mm和265mm,与未切顶相比分别降低了12.68%和70.22%,围岩整体稳定性较好。该研究可为相同或相似条件下切顶留巷技术应用及关键参数设计提供参考和借鉴。

高地应力下深部硐室底鼓破坏围岩稳定性分析

为研究西部山区高地应力作用下深部硐室的稳定性问题,根据普氏压力拱理论,综合考虑深部硐室冒顶,片帮以及底鼓破坏,建立了高地应力下深部硐室底鼓破坏模式,基于极限分析上限法和非线性Hoek-Brown破坏准则,推导了该破坏模式下深部硐室的围岩压力理论公式,求解了该破坏模式下深部硐室围岩压力上限解,并将本文结果与数值模拟和已有成果进行对比分析。此外,通过该破坏模式研究了各参数对围岩压力和潜在破坏面的影响。结果表明:(1)随着初始地应力场参数中σ_(V)和λ增大,深部地下硐室围岩压力q逐渐增大,硐室围岩潜在破坏面逐渐增大,其中σ_(V)表现尤为显著;(2) Hoek-Brown破坏准则参数中GSI、σ_(ci)和m_(i)的增大对深部硐室围岩稳定性有明显的提高效应,而D增加则会降低硐室围岩的稳定性;(3)随着底部压力相关系数μ增加,深部地下硐室顶板和两帮的围岩压力表现为减小的趋势。研究成果可为深部硐室的支护设计提拱有效的理论支撑。

聚酯装置热媒加热系统技术经济比较分析

从技术经济角度对聚对苯二甲酸乙二醇酯(PET)装置两种主要的热媒加热方式,即天然气热媒炉加热方式和高压过热蒸汽加热方式进行了比较分析。依托具体项目,针对不同的工艺流程、设备配置及装置布置,对比了两种方式的投资和运行费用,并结合安全环保、运行维护等方面的优劣,对宜采用的加热方式给出指导意见。

某项目CO_(2)捕集液化工艺浅谈

尽管工业取得了巨大进步,但由于温室气体,特别是二氧化碳的排放,化石燃料的大规模燃烧导致了严重的环境和气候问题。实现低碳排放和绿色碳转型已成为化学家追求的首要目标之一。目前已经使用了许多方法来减少CO_(2)排放,通常包括“碳捕获和储存”和“碳捕获与利用”。其中,将二氧化碳捕获与液化技术联合起来是储存乃至进一步利用的主流有效方法。在本文中,采用中压液化工艺技术路线,在吸收塔、解吸塔及液化单元的逐级作用下,可实现产品气CO_(2)纯度高,含水率<1%;气相分压小,CO_(2)吸收剂损失小;吸收剂稳定性好,无腐蚀性,无需昂贵的建设材料等优点。此外,这项工作旨在合理设计二氧化碳气体的液化处理单元,用以净化去除原料气中的其他杂质成分,从而获取高纯液体CO_(2),对于工业应用也至关重要。

高应力断层构造区巷道冲击破坏特征研究

断层构造区静动载应力耦合作用加剧了井下断层区围岩冲击危险性,断层构造区巷道围岩应力分布规律及冲击动载响应特征存在显著特殊性。目前对于断层构造区的冲击研究主要集中于工作面采场附近,但对于断层构造区巷道冲击破坏鲜有研究。以陕西某矿深埋高应力断层构造区巷道为工程背景,分析了断层构造区巷道围岩变形破坏力学特征:①断层面存在明显应力阻隔效应,正断层附近存在上盘应力集中区和下盘应力降低区2个特殊应力区。巷道由于断层面影响,巷帮静载集中应力呈现非对称分布特征,远离断层面侧应力集中程度大于靠近断层面侧,该侧巷道围岩冲击破坏危险程度增大。②断层面对于应力波传递产生明显阻隔作用,正断层上盘动载响应大于下盘动载响应,由于巷道两帮应力非对称分布特征,右帮动载响应明显大于左帮。基于上述特征,提出了断层构造区巷道围岩“卸(大直径钻孔卸压)−支(梯次加固成层式吸能防冲支护)”协同防冲控制技术,工程试验结果表明:①巷道围岩采取“卸−支”协同防冲处理措施后,巷道两帮应力集中区往围岩深部转移3~5 m,应力峰值降低18.5%~20.3%,巷道帮部围岩应力集中程度显著降低。②采用“卸−支”协同防冲处理措施前,巷道顶底板及两帮变形量分别为856,334,325,567 mm,巷道围岩变形破坏严重,采用“卸−支”协同防冲处理措施后,巷道围岩变形量降低35.69%~62.03%,巷道围岩稳定性增强。③钻孔煤粉量显著低于临界粉煤量,巷道围岩动力显现降低。

储氢技术研究现状及进展

储氢环节是连接氢生产到应用的桥梁,也是高效利用氢能的基础。高压气态储氢技术最成熟、应用最广泛,研制轻质、高压、耐腐蚀性强、稳定性好的储氢容器将是未来高压储氢的研发热点。固态储氢是利用固体材料吸附方式实现氢的存储,主要包括金属材料、复合氢化物、碳基材料、有机框架储氢材料、无机多孔储氢材料等。从储能密度角度看,低温液态储氢是一种十分理想的储氢方式,但也存在能量损失大、成本高昂等问题。有机液态储氢具有储氢密度大、安全性好、载体可循环使用等显著优点,被认为是最有希望实现大批量、远距离氢储运的重要方式之一,甲基环己烷(MCH)、二苄基甲苯(DBT)、N-乙基咔唑(NEC)、甲醇/甲酸等是当前有机物储氢介质的研究热点且具有商业化前景。目前有机液态储氢还存在脱氢效率低、能耗大、氢纯度不足等问题,大部分技术仍处于研究或初期示范阶段。短期内高压气态储氢仍是储氢方式的主流选择。中期内发展的重点是有机液态储氢和固态储氢,低温液态储氢主要应用在大批量、长距离的特殊储运场景。长期来看,融合多种储氢方式的优点,开发集成式耦合储氢技术是未来发展的关键,高效、长寿命、经济性好的储氢介质/催化剂体系是未来储氢技术的研究重点。

核电高中压外缸全尺寸检测方法

着重介绍核电高中压外缸全尺寸检测的过程,通过工业摄影测量系统、三坐标划线仪、测厚仪等测量设备,结合对应的软件系统,对核电高中压外缸进行全尺寸的检测,确保产品尺寸完全符合顾客图纸要求。相较于传统测量方法,对于重量大、尺寸测量数据多的产品,全尺寸测量不仅能够覆盖100%尺寸检验,并且检验效率和精度有了极大的提高。

M701F4改进型燃气-蒸汽联合循环中低压合缸机组冷态快速启动优化

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