现场测试地下岩土平均热物性参数方法

平均热物性参数的大小对钻孔的数量及钻孔的深度具有显著的影响,进而影响地源热泵系统的初投资。为了能够在现场测量地下岩土的平均热物性参数,利用一套现场测量设备测量了对地下埋管回路施加的热流与回路中循环水温度随时间的变化,使用自行开发的软件,采用参数估计方法,计算并确定了地下岩土的平均热物性参数。     

增强型地热系统中溶解二氧化碳对热储层溶蚀作用的实验研究

增强型地热系统(EGS)是通过人工形成热储层的方式从深部低渗干热岩体中经济地开采地热能的人工地热系统。为了增强热储层的孔隙度和渗透率,需要对热储层的人工裂隙实施化学刺激,增加深部岩体中地热能的采收率。文章针对松辽盆地地热储层岩石对CO_2的反应进行了实验研究,分别对目标储层的流纹岩和花岗岩进行了高温高压水-岩-气研究,结果表明,在溶解CO_2的作用下,石英、钾长石、钠长石和方解石均出现了溶蚀现象,其中方解石的溶蚀最为强烈。实验中发生了石英、伊利石和含"C"新矿物的沉淀反应。     

一些参数对地热流体生产量的影响

对一个与生产井结合的集总参数热储模型，评估了地热流体生产量的变化。据研究结果得出结论：①在生产开始后不久，直到热储到饱和状态，流量急剧下降；②之后，保持一段时间稳定，在无回灌情况下突然下降。尽管回灌低温水，但流量仍然逐渐减少；③如果来自热源的流体流入量大到足以使热储保持非饱和状态，则流量可长时间（超过1×10^5h）保持稳定。     

热物性参数对钢坯炉内加热模型精度的影响分析

热物性参数直接影响钢坯的导热过程,在模拟钢坯炉内加热过程如果热物性参数选取不合理,势必造成计算结果严重失真,导致模型精度不高。针对某一钢种的热物性参数进行了实测,并将各种方法获得的热物性参数应用于钢坯加热过程的数值模拟计算,对比分析其对钢坯炉内加热过程模拟计算精度的影响。     

地下渗流对砂土热物性参数的影响程度分析

在浅层地热能利用中,获取准确的岩土体热物性参数对地源热泵系统优化设计非常重要,但因原位测试常常受到地下水渗流的影响,导致所得参数不准确,从而使系统的设计浪费或失效。为此,设计了一套渗流控制系统,结合线热源测试原理,测试了长江一级阶地汉口地区的两种饱和砂土样在不同渗流速率下的热物性参数,并引入贝克来数评价了渗流作用对砂土传热性能的影响。结果表明,渗流对饱和砂土的热传导特性测试结果有明显的影响,且影响程度随渗流速率的增加而增强,对德国纽伦堡市一处地源热泵系统的测试亦验证了渗流对导热系数测试结果的增强作用。     

地热系统热储温度评价方法探讨

目前我国研究地热系统热储温度的评价方法主要有二氧化硅地热温标法和阳离子地热温标法,这2种方法对于高温热田的热储温评价应用较为成功,但对于低温热田会出现明显数据偏差。在前人研究基础之上,通过对国际上相关地热井水化学资料的收集分析,利用上述2种方法对其热储温度进行计算与对比,探讨各种估算结果的可靠性和不同地热温标的适用条件,可为今后更好地进行热储温度评价提供参考依据。     

多组分气体热物性参数的计算方法

在现有工质热物性质计算公式的基础上,结合实验数据,研究了多组分气体热物性参数的计算方法,选择合适的计算模型,编制了计算多组分气体热物性参数的软件,并对采用该软件得到的计算结果与试验值进行了比较.结果表明:所确立的混合模型合理、可靠;通过编程计算多组分气体的热物性参数具有便捷、可靠、精度高的特点.     

增强型地热系统（EGS）的人工热储技术

文章分析了增强型地热系统（干热岩）发电原理,研究该系统建立人工热储的关键技术,包括人工致裂、监测、裂隙网络的连通、封闭水流循环、热储系统建模等。最后分析了芬顿山、Hijiori、苏尔士大型试验电站的人丁热储应用实例。     

物性参数对硅单晶Czochralski生长过程的影响

为了了解硅单晶C zochra lsk i(C z)法生长时物性参数对熔体流动和氧传输过程的影响,利用有限元法对炉内的传递过程进行了全局数值模拟,假定熔体和气相中的流动都为准稳态轴对称层流,熔体为不可压缩流体,C z炉外壁温度维持恒定。结果表明:熔体的导热系数及发射率对熔体流动、加热器功率、结晶界面形状、晶体内轴向温度梯度和氧浓度有重要影响,而熔体的密度、黏度系数及熔解热对硅单晶C z法生长过程影响较小。     

A novel flow-resistor network model for characterizing enhanced geothermal system heat reservoir

The fracture characteristics of a heat reservoir are of critical importance to enhanced geothermal systems, which can be investigated by theoretical modeling. This paper presents the development of a novel flow-resistor network model to describe the hydraulic processes in heat reservoirs. The fractures in the reservoir are simplified by using flow resistors and the typically complicated fracture network of the heat reservoir is converted into a flow-resistor network with a reasonably simple pattern. For heat reservoirs with various fracture configurations, the corresponding flow-resistor networks are identical in terms of framework though the networks may have different section numbers and the flow resistors may have different values. In this paper, numerous cases of different section numbers and resistor values are calculated and the results indicate that the total number of flow resistances between the injection and production wells is primarily determined by the number of fractures in the reservoir. It is also observed that a linear dependence of the total flow resistance on the number of fractures and the relation is obtained by the best fit of the calculation results. Besides, it performs a case study dealing with the Soultz enhanced geothermal system (EGS). In addition, the fracture numbers underneath specific well systems are derived. The results provide insight on the tortuosity of the flow path between different wells.     

CO_2热泵机组在供热系统中的应用

通过采用喷射式双极性结构的CO_2热泵机组作为供热系统的制热核心设备,辅以先进的耦合和变频自动控制技术,使得CO_2热泵机组供热系统得以在高寒地区仍然具有COP最大可达4.5的极佳效果,大大拓展了CO_2热泵机组应用区域,为用户提供了更环保、更经济的供热方案。     

热回收式CO2制冷系统性能研究

对热回收式CO2制冷系统性能COP进行了计算和分析,结果表明:蒸发温度、气体冷却器出口CO2温度、热水加热器入口水温是影响其COP的主要因素;回热器出口过热度对COP的影响较小,对压缩机的排气温度影响较大;随着排气压力的升高,COP是否出现峰值,取决于气体冷却器入口制冷剂的特征温度;在相同工况下,蒸发温度、气体冷却器出口CO2温度、回热器出口过热度对最佳排气压力的影响较小,热水加热器入口水温是影响最佳排气压力的主要因素。     

增强型地热系统热开采性能的数值模拟分析

增强型地热系统(EGS)作为一种极富发展潜力的可再生清洁能源利用技术,正逐渐成为世界各国新能源发展的重点关注方向之一。EGS地下采热过程直接影响EGS的产能和寿命。文章使用一套自主开发的三维动态数值模型对不同地质条件下双井EGS的长期热开采运行进行了模拟,额外引入平均产热速率和地热开采率作为采热性能评价指标,结合EGS运行寿命和产热速率综合分析了热储渗透率、循环流体流量和周围热储岩石的热补偿对采热的影响及其作用机理。     

超临界CO_2的携热优势及在地热开发中的应用潜力分析

利用超临界CO2作为工作介质,循环携带地热或驱替地下热水,是一种新颖的地热开发技术。文章在介绍超临界CO2携热优势的基础上,评价了不同类型地热储层注CO2开采地热的应用潜力。超临界CO2采热能力强,对岩石矿物溶解度小,还可与地质埋存技术相结合,适用于干热岩以及沉积岩地热资源的开发。干热岩开发主要考虑采用超临界CO2作为携热介质,沉积岩地热资源储量丰富、孔隙表面积大、地质条件安全,应是注CO2开采地热和地质埋存的首选。     

Fluid circulation and heat extraction from engineered geothermal reservoirs

A large amount of fluid circulation and heat extraction (i.e., thermal power production) research and testing has been conducted on engineered geothermal reservoirs in the past 15 years. In confined reservoirs, which best represent the original Hot Dry Rock concept, the flow distribution at any given time is primarily determined by three parameters: (1) the nature of the interconnected network of pressure-stimulated joints and open fractures within the flow-accessible reservoir region, (2) the mean pressure in the reservoir, and (3) the cumulative amount of fluid circulation—and therefore reservoir cooling—that has occurred. For an initial reservoir rock temperature distribution and mean fluid outlet temperature, the rate of heat extraction (i.e., thermal power) is at first only a function of the production flow rate, since the production temperature can be expected to remain essentially constant for some time (months, or even years). However, as reservoir circulation proceeds, the production temperature will eventually start to decline, as determined by the mean effective joint spacing and the total flow-accessible (i.e., heat-transfer) volume of the reservoir. The rate of heat extraction, which depends on the production flow rate, can also vary with time as a result of continuing changes in the flow distribution arising from reservoir cooling.The thermal power of engineered reservoirs can most readily be increased by increasing the production flow rate, as long as this does not lead to premature cooldown, the development of short-circuit flow paths, or excessive water losses. Generally, an increase in flow rate can be accomplished by increasing the injection pressure within limits. This strategy increases the driving pressure drop across the reservoir and the mean reservoir pressure, which in turn reduces the reservoir flow impedance by increasing the amount of joint dilation. However, the usefulness of this strategy is limited to reservoir operating pressures below the fracture extension pressure, and may lead to excessive water losses, particularly in less-confined reservoirs. Under such conditions, a downhole production-well pump may be employed to increase productivity by recovering more of the injected fluid at lower mean reservoir operating pressures.     

增强型地热系统能耗及CO_2排放强度的生命周期评价

以装机容量10 MW的增强型地热系统(EGS)为例,对其生命周期内能耗和CO2排放进行详细核算,结果表明:EGS能耗以造井和储层建造阶段能耗为主,分别占生命周期能耗的80.04%和12.73%。EGS能耗强度和CO2排放强度(合标准煤)分别为3.45 g/kWh和8.25 g/kWh,能耗强度略高于风电,显著低于光伏发电与火电;CO2排放强度以EGS为最低,相较国内单位发电量764 g/kWh的碳排放,EGS服役期满20 a后,可实现减排CO2106万t。     

使用热泵的地热水供热系统

目前普遍存在地热水不合理使用现象，文中介绍使用热泵和回灌的新型地热水供热系统及热力计算，认为可解决地热水浪费和地热供热事业可持续发展问题。     

Radon in geothermal reservoir engineering

Radon has been shown to have potential as a tracer in the study of geothermal reservoirs. The combination of its physical and nuclear properties and its emanation and transport in geothermal fluids makes several types of time and concentration measurements useful for studies of fracture permeability and porosity and flow characteristics in different types of geothermal resources. Radon concentrations in several vapor-dominated and liquid-dominated producing reservoirs have been measured by short-period sampling of wellhead geofluid followed by radon separation on a charcoal trap and counting in a sensitive low background ZnS detector. The results show significant variations not only among different fields, but also between neighbouring wells in a single field. Evidences for transport differences between the two major types of hydrothermal systems are noted.     

节能环保型CO_2热泵热水系统在浴室中的应用

考虑对某建筑楼浴室设计以CO_2作为媒介的新型热水系统去取代传统锅炉设备进行热水供应。采取了大温差小流量的运行方式,使得在稳定产热水的同时,既能节能环保,又能节约经济。从系统设计、性能优化、经济性的角度研究分析此系统的可行性,并对主要设备进行选型。最后将CO_2热泵设备跟传统燃油、燃气锅炉以及电锅炉设备进行对比并分析各项指标的优劣。