双U型埋管地热换热器的传热模型

合理地分析地热换热器中的传热过程是保证地源热泵空调系统经济可靠地运行和降低其初投资的要求 ,因而确定钻孔内热阻对于设计地源热泵空调系统中的地热换热器具有重要的意义。本文采用准三维模型对于对称布置的双U型埋管地热换热器钻孔内的传热情况进行了分析研究。在考虑各支管间的“热短路”的条件下 ,导出了循环流体在各个支管内沿钻孔深度方向上温度变化的解析表达式 ,进而确定了双U型埋管地热换热器钻孔内的热阻。这一理论模型为进一步定量分析影响双U型埋管地热换热器传热性能的诸多因素奠定了基础     

俄罗斯穆特诺夫斯克现代地热电站的建设

俄罗斯穆特诺夫斯克地热电站总装机容量50MW，是一座在电力和热能生产上有重大突破的新型样板地热电站。为此，介绍了穆特诺夫斯克现代地热电站现状，对地热电站设备、汽轮发电机组、热力系统结构与特点作了阐述。地热发电与传统燃煤、燃油、燃气电厂相比，具有生态洁净、节约燃料运输贮存和管理费用、建设周期较短等优势。鉴于目前我国地热发电正处于起步阶段，地热发电装机容量只占世界上地热电站的装机总容量很少份额，因而可加快我国地热资源的开发应用，促进我国地热电站的发展。     

地热发电简述

目前世界上实际能利用的地热资源很少,主要限于蒸汽田和热水田,这两者统称为地热田。地热蒸汽田以蒸汽为主,温度较高,一般为160℃以上,可将地热蒸汽田的蒸汽直接引入普通汽轮机发电。地热热水田则以热水为主,温度较低,一般为50～160℃,这就需要将地热水中的热能转换成地热蒸汽引入普通汽轮机发电。地热电站既没有燃料运输设备,也没有庞大的锅炉设备,所以也就没有灰渣和烟气对环境的污染,是比较清洁的能源。地热发电站发电后排出的热水,可供诸如采暖、医疗、洗涤、提取化学物质和农业养殖。地热发电成本较水电、火电都低。     

地热水医疗保健作用评价

在查阅大量文献的基础上,分析了地热水中各种有益组分的医疗保健作用机理;以河南省出露温度最高的洛阳九龙山疗养院温泉为典型例子,根据水质检测结果,按照《医疗矿泉水水质标准》(GB11615-89)对其医疗作用进行了评价;结果表明,该处地热水中多种组分具有医疗价值质量浓度或达到命名医疗热矿水名称的质量浓度,具有较高的医疗价值和保健作用.     

酒西盆地原油溶解气中稀有气体同位素特征研究

对酒西盆地青西坳陷青西油田和南部隆起鸭儿峡油田8个原油样品进行了稀有气体测试分析,探讨了原油中氦的来源问题.青西油田4口井和鸭儿峡油田527井、702井原油3He/4He (Rc)为10-8量级,推测其原油中稀有气体是壳源放射性成因的,同时也说明与青西油田和鸭儿峡油田527井、702井有关的推覆断层的切割深度限于地壳范围内.鸭儿峡油田501井、114井原油样品3He/4He (Rc)达10-7量级,说明有少量幔源氦的混入,而与这两口井有关的推覆断层的切割深度可能已达地幔.酒西盆地大地热流值较低,平均50.9mWm-2(6),表明其大地构造活动性较我国东部盆地弱.     

The Podhale geothermal reservoir simulation for long-term sustainable production

The Podhale geothermal system, located in the southern, mountainous part of Poland, is the most valuable reservoir of geothermal waters discovered in the country to date and the one with the highest capacities in Central and Eastern Europe. Over 20 years of continuous operation has proved its stable operating parameters – a small drop in pressure and an unnoticeable temperature change. Production of over 500 m³/h of geothermal water with an 86 °C wellhead temperature is current practise, while drilling a new production well and reconstruction of an injection well allows for production that may significantly exceed 600 m³/h. To utilize these vast resources, a binary power cycle for electricity and heat production is considered by group of researchers. The results of numerical modelling of heat extraction from the Podhale reservoir are presented in the article as a preliminary step to the detailed analysis of combined heat and power production through a binary power cycle.     

地热系统碳酸钙垢形成原因及定量化评价

碳酸钙垢是我国喜马拉雅构造带高温地热系统开发利用面临的主要问题之一,其直接原因是流体中Ca²⁺和CO₃^2- 的活度积大于当前温度下的平衡常数,通常与pH值增大有关。导致pH值增大的过程包括井筒内的沸腾作用促进CO₂脱气,套管腐蚀消耗质子,流体上升过程中的减压作用以及其他气体的侵入导致的CO₂逃逸,主控因素是沸腾作用。本文建立了一套系统评价地热流体结垢趋势、位置和规模的方法。首先基于地热流体经历的地球化学过程（如沸腾、混合、结垢等）,利用井口或者泉口样品的数据和地球化学程序重建储层流体的化学组分;利用水文地球化学模拟程序或者雷兹诺指数,计算碳酸钙的饱和指数,评价其发生结垢的趋势。其次利用井径测井或者井筒模拟和地球化学模拟,定量给出发生结垢的深度及范围。此外,储层和井口流体Ca²⁺ 浓度差异和平衡模拟方法以及碳酸钙结垢厚度评价方法可用于定量计算一定开采时间内的结垢量,其结果与实际情况具有可比性;对于川西某结垢地热井,48 h内的结垢量达151 ~ 300 kg或结垢厚度为1 ~ 3 cm。碳酸钙形成原因分析和定量化评价可为下一步的防垢或者除垢设计提供科学依据。     

北京市地埋管地源热泵项目应用效果评价分析

通过对27个北京市地埋管地源热泵项目应用数据的监测调查，从系统性能、地温变化、节能效益、环保效益和节能成本等方面进行统计分析，并应用主成分分析法和数据包络分析法对项目的效率进行综合评价，得出效率相对有效的项目17个，相对无效的项目10个，并分析无效项目的参数改进方向。最后提出地埋管地源热泵发展的4点建议：1）增加财政补贴可有效提高项目的投入产出效率；2）项目参数设计的合理性和运维管理的科学性是决定项目效率的根本因素；3）加强长期监测才能对地源热泵技术对环境影响程度有更准确的判断；4）优化项目投入产出效率是地埋管地源热泵项目普遍应用需要解决的重要问题。     

Temperature-induced impacts on groundwater quality and arsenic mobility in anoxic aquifer sediments used for both drinking water and shallow geothermal energy production

Aquifers used for the production of drinking water are increasingly being used for the generation of shallow geothermal energy. This causes temperature perturbations far beyond the natural variations in aquifers and the effects of these temperature variations on groundwater quality, in particular trace elements, have not been investigated. Here, we report the results of column experiments to assess the impacts of temperature variations (5°C, 11°C, 25°C and 60°C) on groundwater quality in anoxic reactive unconsolidated sandy sediments derived from an aquifer system widely used for drinking water production in the Netherlands. Our results showed that at 5 °C no effects on water quality were observed compared to the reference of 11°C (in situ temperature). At 25°C, As concentrations were significantly increased and at 60 °C, significant increases were observed pH and DOC, P, K, Si, As, Mo, V, B, and F concentrations. These elements should therefore be considered for water quality monitoring programs of shallow geothermal energy projects. No consistent temperature effects were observed on Na, Ca, Mg, Sr, Fe, Mn, Al, Ba, Co, Cu, Ni, Pb, Zn, Eu, Ho, Sb, Sc, Yb, Ga, La, and Th concentrations, all of which were present in the sediment. The temperature-induced chemical effects were probably caused by (incongruent) dissolution of silicate minerals (K and Si), desorption from, and potentially reductive dissolution of, iron oxides (As, B, Mo, V, and possibly P and DOC), and mineralisation of sedimentary organic matter (DOC and P).     

Engineered geothermal power systems for Singapore

Singapore has a high geothermal gradient (～35°C/km) as evidenced by hot springs (70°C) and high heat flow (estimated to be about 130 mW/m²). In this study, ground water models are presented based on AUTOUGH–2 computer modelling. The models show a freshwater lens up to 4.8 km depth under Singapore's land area, whose temperature increases with depth up to 192°C. Three geothermal prospects are identified: an engineered geothermal system (EGS) in hot, wet granite on the main island; an EGS in hot, wet volcanics or granite on Pulau Tekong and hot sedimentary aquifers (HSAs) in the Jurong Formation, both on and off-shore. Geothermal water at 150°C could be used for electricity generation, industrial process heating and desalination. A cost estimate exercise for a district cooling system (DCS) powered by 90°C geothermal water shows that there are significant economic advantages. A feasibility study is required.