利用金矿尾矿烧制陶粒的正交实验研究

采用正交实验方法研究金矿尾矿掺量、粉煤灰掺量、煤粉掺量、预热温度、预热时间、焙烧温度、焙烧时间7个因素对陶粒制品性能的影响;以陶粒的堆积密度、筒压强度和吸水率性能作为考查指标,得出烧制陶粒的最优方案。结果表明,金矿尾矿掺量为55 g,粉煤灰掺量为34 g,煤粉掺量为3 g,预热温度为450℃,预热时间为60 min,焙烧温度为1 150℃,焙烧时间为120 min时,制得的陶粒综合性能最好。     

利用钢渣和淤泥烧制陶粒的研究

介绍了以钢渣和淤泥为原料烧制陶粒的工艺,研究了钢渣掺量、烧成温度以及焙烧时间对陶粒性能的影响.结果表明,在淤泥中掺入一定量的钢渣可以烧制出符合标准规定的陶粒,所得陶粒吸水率很低,但钢渣掺量不宜过高.     

污泥陶粒制备工艺烧结温度影响研究

为明确陶粒制备工艺的烧成温度范围,考察焙烧机制,进行了不同温度污泥烧制页岩陶粒的实验研究。结果表明,工艺控制参数耐火度:Al2O3/+SiO2Fe2O3+CaO+MgO+Na2O+K2O可以表征混合料烧成开始温度;1000℃以下烧制陶粒的孔径分布为单峰曲线,1050～1100℃烧制陶粒的孔径呈现双峰结构,焙烧机制对陶粒孔隙分布有如下影响:提高焙烧温度,峰值孔径增大,延长焙烧时间,峰值孔径相对位置增加;XRD分析表明,陶粒主要晶相为石英和蓝晶石,在1050℃以上烧结,孔分布出现双峰曲线,可能与氧化铁分解有关。     

纺织污泥对免烧陶粒的制备及性能影响研究

以纺织污泥为主要原料制备免烧陶粒。通过实验分析探究了污泥/水泥比、粉煤灰添加量和养护时间对陶粒性能的影响。结果表明:纺织污泥基免烧陶粒的最佳原料配比和养护工艺为污泥/水泥比为2.25,粉煤灰添加量为5%,粘结剂添加量为1%,养护时间为28天。该条件下制得的陶粒筒压强度为6.93 MPa,堆积密度为753kg/m~3,1 h吸水率为17.98%。满足GBT17431.1《轻集料及其试验方法》中普通轻质骨料的性能指标。针对纺织污泥中Zn含量较高的特点做了浸出毒性测试,Zn浸出达到相关标准要求。SEM与XRD分析发现,最优条件下陶粒内部孔隙封闭,晶粒紧密结合;水化硬化反应生成的C-S-H和钙矾石类晶态组织,有利于提高陶粒的综合物理性能。     

污泥对水泥熟料烧成和强度的影响

利用污水处理厂污泥替代硅质原料配制多组水泥生料,污泥掺量变化范围0-10%,生料KH(石灰饱和系数)变化范围为0.88~0.97,在1400℃下煅烧,测定各熟料的f-CaO和强度,并结合XRD,SEM/EDS等分析,研究污泥掺量及生料KH对水泥熟料烧成和强度性能的影响。另外还对掺10%污泥所烧制的熟料进行了重金属溶出试验。结果表明,在生料KH保持0.94而污泥掺量变化的情况,污泥掺量在2.5%左右时对改善生料的易烧性和熟料强度均有利,而污泥超过这个掺量后,生料易烧性和熟料强度随污泥掺量增加而明显降低;在污泥掺量保持2.5%而KH变化的情况下,KH小于0.91时,掺入污泥对生料易烧性和熟料强度不利,而KH大于0.94时,污泥掺入能改善生料易烧性,对熟料强度也略有提高;即使水泥生料中污泥掺量高达10%,所烧制的水泥其重金属滤出值远远小于标准的规定值,不会对环境产生危害。从水泥生料易烧性、熟料强度和重金属溶出试验看,只要生料配比合理和污泥掺量合适,污泥可以在水泥生产中得到无害化处置和资源化利用。     

疏浚底泥-大理石废粉陶粒的制备工艺及性能

通过对两河段底泥(DSⅠ和DSⅡ)、大理石废粉(MWP)两种固体废弃物的化学组成及热稳定性分析,确定制陶原材料配比与工艺参数范围,设计了以不同原料配比、预热时间、焙烧温度、焙烧时间为因素,以堆积密度、吸水率、抗压强度和除磷率为水平的正交实验,并根据正交实验结果分别确定了一种制备高强建筑轻集料(DMC-HC)和一种高效除磷滤料(DMC-HP)的最佳原料配比和工艺参数,利用XRD观察不同性能的DMC物相变化,分析DMC抗压性能与除磷性能的形成过程。结果表明,底泥与大理石废粉能够很好地制备陶粒,在原料配比为DSⅠ∶DSⅡ∶MWP=2∶1∶0.8、预热时间为10 min、焙烧温度为1 060℃、焙烧时间为10 min时,可制得堆积密度为696.29 kg/m~3,表观密度为1 430 kg/m~3,空隙率为52.23%,吸水率为33.42%,抗压强度为2.37 MPa,破碎率于磨损率之和为4.12%,盐酸可溶率为1.56%,比表面积为2.06 m~2/g的高效除磷陶粒;DSⅠ∶DSⅡ∶MWP=2∶1∶0.8、预热时间为5 min、焙烧温度为1 180℃、焙烧时间为15 min时,制得堆积密度为950.35 kg/m~3、吸水率为1.5%、抗压强度为25.53 MPa的低吸水率、轻质高强陶粒。结合XRD物相分析表明:陶粒主要通过化学沉淀达到高效除磷效果,在1 180℃时形成的蓝晶石和铝酸钙是使陶粒获得高强性能的主要原因。     

掺加页岩与粉煤灰对污泥脱水性能的影响

改善污泥的脱水性能有利于污泥的处置与利用,以污泥建材资源化为目标,实验研究了在污泥沉降浓缩阶段加入页岩和粉煤灰后对沉降污泥脱水性能的影响。结果显示单掺页岩或粉煤灰后污泥的脱水性能得到显著改善;污泥比阻从处理前的1013数量级降至1011数量级;污泥脱水后的含水率降低,有利于后续的处理和利用;污泥脱水后的体积有一定程度增大,但这种体积增大在污泥的建材资源化利用方面是可接受的。混掺页岩和粉煤灰后对污泥脱水性能的改善效果优于单掺,页岩与粉煤灰掺量均为5%时,污泥的脱水性能得到最佳改善,且脱水污泥体积无明显增加。     

铬污染土壤-粉煤灰陶粒制备工艺研究

针对我国面临的严重铬污染威胁,进行了将铬污染土壤与粉煤灰混合后在高温下解毒,获得陶粒产品以实现资源化利用的研究。通过单因素试验,以Cr(Ⅵ)浸出浓度和陶粒颗粒强度为控制指标,优选陶粒制备的焙烧工艺参数;通过正交试验得到最优陶粒产品,并分析焙烧工艺条件对陶粒性能的影响机制。结果表明,在焙烧温度1 120℃、粉煤灰添加量25%、焙烧时间10min的试验条件下得到了最佳的陶粒产品;其中焙烧温度是影响陶粒性能的关键因素,对陶粒颗粒强度、表观密度、1h吸水率均影响显著;最终陶粒产品堆积密度等级为600级,筒压强度为3.0 MPa,属于普通轻集料优等品;陶粒浸出液Cr(Ⅵ)浓度0.042 mg/L,浸出液总铬浓度0.045mg/L,安全性能符合《铬渣污染治理环境保护技术规范》(HJ/T301)对铬污染土壤解毒后用于混凝土骨料的处理要求。     

焙烧温度对污泥陶粒烧胀过程及结构特征的影响

按质量比为m(污泥)∶m(盐渍土)∶m(蒙脱土)=75∶20∶5的配比,将料球分别烧至1000℃、1050℃、1100℃和1150℃,研究了焙烧温度对污泥陶粒烧胀过程和结构特征的影响。结果表明,1100℃时陶粒的主晶相是石英、蓝晶石和钙长石,1150℃时陶粒的主晶相是莫来石、石英和蓝晶石。莫来石是由蓝晶石转化而来,在高温时形成富硅铝和富钙的液相以及二液分相现象,最后生成莫来石、玻璃体和钙长石。陶粒烧胀的原因是在还原气氛下发生铁碳反应。陶粒内部形成玻璃体为主体,中间有莫来石增强相的结构,陶粒断面形成致密结构和均匀的封闭孔。     

污泥填料制备实验研究

本文是以脱水污泥为骨料制备用于污水处理中生物膜载体填料,探索了以废制废、污泥资源化的新途径.实验使用脱水污泥为主要原料、粉煤灰和牯土为添加剂,得到制备填科最佳成分配比和最佳工艺条件是烧成温度为1000±25℃、污泥掺量为70%、保温时间为40min,填料的抗压强度达到25Mpa、吸水率17%,污泥填料处理药厂废水常温下CODCr的平均去除率为74.091、SS去除率为54.1%.结果表明,污泥作骨科,可以制备出性能优良的填料.     

Numerical simulation study of shale gas reservoir with stress-dependent fracture conductivity using multiscale discrete fracture network model

The exploitation of shale gas has increasingly become the focus of worldwide energy industry. Due to the existence of natural/hydraulic fractures, most of the shale gas reservoirs exhibit high degree of heterogeneity and complexity which leads to the stress-dependent fracture conductivity of shale gas reservoir. Discrete fracture network (DFN) model is adopted in this research since the conventional continuum model cannot meet the numerical simulation requirements of fractured shale gas reservoir. A series of experiments about the fracture properties stress-dependent have been conducted on some shale core samples, the stress-dependent fracture conductivity correlation is selected and incorporated into the mathematical model to characterize the reduction of fracture conductivity potential with the reservoir pressure drop. The DFN model is applied to a shale gas reservoir with fracture network to study the effect of the stress-dependent fracture conductivity on the shale gas well performance. The results show that the effect of fracture conductivity reduction with pressure drop on the shale gas well performance depends on both the initial fracture conductivity and matrix permeability. The complex interactions between the fracture and matrix permeability should be considered when select the appropriate size of proppants for fracturing.     

页岩陶粒对混凝土破坏特征及机理影响的研究

研究了用不同体积掺量(0%,50%,100%)页岩陶粒取代普通骨料配制的不同水胶比混凝土的应力-应变关系,以及混凝土内部水泥石和骨料的弹性模量与显微硬度,同时对砂浆和混凝土强度之间的发展关系进行了分析,力图探讨页岩陶粒对混凝土破坏特征及机理的影响.结果表明,随页岩陶粒掺量的增加,混凝土应力-应变全曲线的上升段斜率变小,下降段的坡度变缓,破坏形式也由斜截面剪切转为纵向劈裂;页岩陶粒的掺入使得混凝土内部骨料与水泥石的界面区得到改善,骨料与基体的显微硬度更为接近,弹性更为协调;在普通混凝土中掺入部分页岩陶粒,当砂浆强度较低时,陶粒周围增强的界面区以及与砂浆较为良好的弹性协调在一定程度上弥补了陶粒自身对混凝土强度的不利影响,混凝土破坏主要取决于砂浆强度;但当砂浆强度较高时,低强度的陶粒会在一定程度上会降低混凝土的强度,但陶粒的"自养护"作用对混凝土后期强度增长有利.     

全球页岩气发展启示与中国未来发展前景展望

中国页岩气勘探开发已开展了大量露头地质调研、前期研究与勘探开发先导试验等工作,尤其是在中国南方海相页岩气区,完钻了页岩气井40余口,获气10余口,多口井经压裂初期日产量超过了1万m3。实践表明,中国页岩气资源发展前景较好,但也具有明显的特殊性,许多地质与开发难题亟待解决,随着页岩气勘探开发理论与关键技术的突破、经济条件的改善和国家政策的支持,未来中国页岩气资源发展前景广阔。     

中国南方页岩气勘探评价的几点思考

中国南方广泛发育下寒武统、下志留统、上二叠统三套海相区域性富有机质泥页岩,同时在四川盆地、江汉盆地和苏北盆地发育陆相富有机质泥页岩,具备形成页岩气的地质条件。但是,与美国页岩气相比,南方海相页岩气具有多期构造运动叠加改造、热演化程度高、保存条件复杂的特点,而陆相泥页岩有机碳含量、孔隙度相对较低,因此南方页岩气勘探面临诸多挑战,不能盲目乐观。笔者等对比研究认为,四川盆地海相、陆相是实现页岩气规模勘探开发的现实领域,江汉盆地、苏北盆地陆相可作为南方页岩气勘探的后备领域。     

济阳坳陷渤南洼陷页岩油气形成条件研究

通过大量地震、钻井、测井、矿物、地球化学、物性资料分析,认为济阳坳陷渤南洼陷古近系沙一段、沙三下和沙四上亚段页岩分布面积广,有机质丰度高,有机质类型以Ⅰ—Ⅱ型为主,有机质成熟度分布范围宽,具备形成大量页岩油气的物质基础,三套泥页岩全岩矿物组成中粘土矿物含量低,脆性矿物含量高,以碳酸盐含量为主,利于页岩油气的开采。页岩中压力系数高,各类微孔隙、微裂缝发育,从而容易形成网状的油气储存体系,利于页岩油气的保存。含油、水饱和度分析资料显示,渤南洼陷沙三下亚段12上—13上层组页岩中具有较高的单位岩石含油气量,是页岩油气勘探的有利层段,其中的纹层状泥质灰岩是最有利的岩石类型,具有较好的页岩油气勘探前景。     

Mixed integer simulation optimization for optimal hydraulic fracturing and production of shale gas fields

Optimal development of shale gas fields involves designing a most productive fracturing network for hydraulic stimulation processes and operating wells appropriately throughout the production time. A hydraulic fracturing network design—determining well placement, number of fracturing stages, and fracture lengths—is defined by specifying a set of integer ordered blocks to drill wells and create fractures in a discrete shale gas reservoir model. The well control variables such as bottom hole pressures or production rates for well operations are real valued. Shale gas development problems, therefore, can be mathematically formulated with mixed-integer optimization models. A shale gas reservoir simulator is used to evaluate the production performance for a hydraulic fracturing and well control plan. To find the optimal fracturing design and well operation is challenging because the problem is a mixed integer optimization problem and entails computationally expensive reservoir simulation. A dynamic simplex interpolation-based alternate subspace (DSIAS) search method is applied for mixed integer optimization problems associated with shale gas development projects. The optimization performance is demonstrated with the example case of the development of the Barnett Shale field. The optimization results of DSIAS are compared with those of a pattern search algorithm.     

Varying-scale shale gas flow: Discrete fracture networks (DFN) based numerical simulation

ABSTRACT

The development of unconventional gas reservoirs represents totally distinctive characteristics as compared with its conventional counterparts. The prevailing commercial strategy of stimulating fractures to connect the matrix to wellbores results in an even more complicated shale gas flow behavior, in which matrix flow is fairly coupled with fracture flow. Numerous works have been contributed to unveil the underground shale gas production mechanisms. And some impressive progresses have been made in describing the complex subterranean shale gas flow, such as the introduction of discrete fracture network (DFN) from National Energy Technology Laboratory (NETL). However, none of them captures the varying-scale nature of the in-place gas flow in shale sediments. In this work, we try to fill this gap. Following the concept of DFN, we set up mathematical models for shale gas flow in matrix and fracture networks, and also for their mass transfer in between without neglecting its varying-scale nature. In addition, we also investigate comprehensively the impact of various effects and phenomena occurred in pore spaces during production course, such as adsorption and desorption on rock surfaces, gas slippage and Knudsen diffusion, and diffusion in bulk kerogen, on the overall shale gas production using our new model for a specific shale gas reservoir case study.     

美国Eagle Ford页岩气开发对我国页岩气勘探开发的启示

据估计,我国的页岩气可采储量高达20万亿～36万亿m3,虽然我国页岩气储量评估处于初级阶段,但仍然可以肯定我国是页岩气资源丰富的国家之一,如果都能开发,按当前的天然气年产量计算,可以开发200多年。目前国内外多家企业聚焦中国,逐鹿页岩气,页岩气有望成为我国常规能源替代品,页岩气的勘探开发必将对我国乃至世界能源格局产生重大影响。但是由于页岩气储层致密,渗透率低至纳达西级,若不采取特殊的增产措施难以实现商业开发。美国是目前唯一实现页岩气商业开采的国家,技术和商业模式都相当成熟,中海石油斥资10多亿美元收购了美国页岩气主产区Eagle Ford 33.3%的股份,该地区页岩气地质储量高达6 000亿m3,开发前景广阔。为提升我国页岩气总体水平,笔者率领技术专家深入考察了美国Eagle Ford页岩气项目,增进了对水平钻井与分段压裂等关键技术的了解,同时分析了相应扶持政策,对中国页岩气的勘探开发具有重要的参考价值。     

Preparation and characterization of silica aerogels from oil shale ash

The silica aerogels were successfully synthesized using oil shale ash which is a by-product of oil shale processing via ambient pressure drying. The physical and textural properties of the silica aerogels have been investigated and discussed. The results showed that the organic modification of hydrogels was a crucial step during the processing which preserved mesopores in ambient pressure drying. The unmodified hydrogel underwent tremendous shrinkage during the drying and yielded microporous silica aerogel. Using this novel route, it could produce silica aerogel with low tapping density of 0.074 g/cm³, high specific surface (909 m²/g) and cumulative pore volume of 2.54 cm³/g. From the industrial point of view, the present process is quite suitable for a large scale production of powdered silica aerogel. Furthermore, it provides a new way to solve the problem of oil shale ash pollution.     

Supercritical fluid extraction of Chinese Maoming oil shale with water and toluene

Chinese Maoming (Guangdong Province) oil shale was subjected to supercritical fluid extraction with water and toluene, respectively, in a batch autoclave. Yields of organic matter were greater with toluene than with water, and more organic compounds of high molecular weight were extracted with toluene than with water, although the weight losses of the oil shale with toluene and water were almost the same. Yield distributions ofn-alkanes were also almost the same, irrespective of the solvent. This paper is dedicated to Dr L K Doraiswamy on his sixtieth birthday.