WATER SUPPLY DILEMMAS OF GEOTHERMAL DEVELOPMENT IN THE IMPERIAL VALLEY OF CALIFORNIA1

Abstract: There are four known geothermal resource areas in the Imperial Valley that have a combined potential of over 4,000 megawatts of electrical energy for 25 years. Water resources available to support geothermal enerfy development are imprted Colorado River water, agricultural waste waters, Salton Sea water, and groundwater. In addtion, geothermal power plants can produce their own cooling water from steam condensate. Nevertheless, the relatively high water requirements of geothermal facilities along with a series of real and potential constraints may cause water supply dilemmas involving both the acquistion and use of cooling water. Important constraints are institutional policies, water supply costs, technical problems, and impacts upon the Salton Sea. These constranits and related dilemmas are examined in light of relevanty information on the valley's water resources, geothermal resources and energy technologies, cooling water requrements, and water supply options.     

Derivation of correlations to evaluate the impact of retrofitted post-combustion CO2 capture processes on steam power plant performance

When integrating a post-combustion CO₂ capture process and CO₂ compression into a steam power plant, the three interface quantities heat, electricity and cooling duty must be satisfied by the power plant, leading to a loss in net efficiency. The heat duty shows to be the largest contributor to the overall net efficiency penalty of the power plant. Additional energy penalty results from the cooling and electric power duty of the capture and compression units.In this work, the dependency of the energy penalty on the quantity and quality of the heat duty is analyzed and quantified for a state-of-the-art hard coal fired power plant. Furthermore, the energy penalty attributed to the additional cooling and power duty is quantified. As a result correlations are provided which enable to predict the impact of the heat, cooling and electricity duty of post-combustion CO₂ capture processes on the net output of a steam power plant in a holistic approach.     

唐山沿海地区地热资源开发利用及前景

唐山南部沿海地区地热资源十分丰富,近年来,地下热水的开发利用得到了初步的发展,但存在项目单一、利用率不高、资源浪费严重等问题。其开发利用应结合地区区位优势以及地热资源的特点,针对用途分层开采,梯级开发,综合利用,加强温泉旅游的拓展,合理、有序、科学地利用地下热水,更好地保护地热资源。     

承德市隆化县茅荆坝地热资源的开发利用

承德市隆化县茅荆坝地热资源丰富,受断裂构造控制,属隐伏基岩裂隙、松散岩孔隙型热储,水温最高可达90℃,地温可达30～40℃,水量充足,水中含有多种医用保健化学成分,但在开发利用中存在着项目单一、利用率不高、资源浪费等问题。地热综合利用和地热梯级利用的开发利用模式,即多目的利用、按不同温度逐级利用,加强科学管理,采取限量打井,限制开采。     

GEOTHERMAL ENERGY IN TRANSITION

At a time when future sources of energy are under close scrutiny, both in terms of availability and suitability, geothermal energy ranks among the candidates for inclusion in any appraisal of alternative forms of supply. The use of geothermal energy for the production of electricity and for supplying domestic and industrial heat is a comparatively recent phenomenon, and its application remains closely constrained by favourable geological conditions. Yet exploration in several countries shows that geothermal energy may emerge as an important adjunct to total energy supply in many localities. McNitt outlines some of the economic and technological parameters of this energy source. Small scale geothermal power stations are more economic and less capital intensive than conventional plants, which make them of particular interest for developing countries with small electricity systems and competing demands on limited capital resources. The principal capital expenditures in the development of geothermal sources include exploration, steam production, installation of generating plant and the cost of effluent disposal. The wider use of low grade geothermal heat is also examined, in addition to the environmental problems occurring to the development of geothermal energy. The scope for technical co-operation in the development of geothermal energy is substantial, and it is likely that this source of energy will undergo more intensive development on the local scale in the future.     

Hybrid input-output analysis to evaluate economic impacts of biomass energy

ABSTRACT

The introduction of the new biomass industry exerts influences that change the interactions among economic sectors by drawing the resources for generating electricity, pricing alterations from the existing market and competitively selling electricity to the power grid. These influences should be described and identified to ensure the benefits to the local economy. In this article, we deem to test the potential of hybrid I-O analysis to analyze the economic impacts and address the change in characteristics of the economic impacts of the biomass power plant. The resource utilization data from the existing biomass power plant located in Kochi Prefecture (Japan) is collected and then analyzed by a hybrid input-output (I-O) analysis. We found that (1) the use of cutoff function could determine the new economy’s structure included the biomass power plant where the allocation of resource in the economy is changed according to the consumption and production of the biomass power plant, (2) The power plant increases the total production of Kochi prefecture’s economy, and this benefit overthrows the negative effect of the loss of resource demand of the existing economic sectors. The use of the hybrid I-O to forecast the economic impacts on the local economy could enhance the decision made by the policymaker.     

市政污泥干化焚烧工艺设计与思考

以南方经济发达地区100 tDS/d的污泥干化焚烧发电工程为例,介绍了污泥处置的热电联用系统.工程利用离心干化设备,以废蒸汽为热源干化污泥,提高热值,干化污泥与生物质在循环流化床锅炉中协同焚烧,焚烧产生的蒸汽通过汽轮发电机组发电自用.烟气经过多级处理后达标排放,废水、飞灰和炉渣都得到有效的处理与处置.该工程的实施缓解了...     

A CLOSED WATER REUSE SYSTEM FOR POWER PLANT COOLING AND DIGESTER HEATING1

ABSTRACT: A model consisting of closed water reuse and productive use of various types of wastes for energy generation is presented. The sewage after treatment would be used as the cooling water for power plants, and the condenser discharge therefrom be used as heating water for sludge digesters. The water is then purified for municipal water supply for continuous use. The advantages of this system are that water resources and energy are conserved while various types of wastes including waste heat are controlled. With a preliminary system analysis, it appears that the design for power plant based on the total heating value of wastes and digester capacity based on sewage sludge generation is feasible in terms of acquisition and full utilization of various types of wastes as generated in a single metropolitan area. The system as shown in this design is in balance among various factors such as the generation rate of municipal refuse, municipal sewage, waste heat in the condenser discharge, and raw sewage sludge.     

Refrigeration waste heat utilization for drying applications: a review

ABSTRACT

Cold chain industry has a vast potential for waste heat recovery. It is a matter of importance for energy efficiency point of view, as global energy demand is increasing day by day. Ample amount of low-grade energy is either unutilized or underutilized. The heat rejected by a Heat pump or refrigeration system emerged as a promising solution for dehydration by utilizing low-grade waste heat despite higher investment. As compared to solar drying technology, heat pump drying evolved as a reliable method regarding better process control, energy efficiency, and quality of the product to be dried. Energy utilized through the refrigeration system’s waste/exhaust heat recovery in combination with or without renewable energy source enhances the overall efficiency of the system and also reduces the cost. This useful review investigated and compared the research findings of waste heat utilization through heat pump and from condenser of refrigeration system on laboratory, pilot as well as industrial scale for drying of various fruits, vegetables, and agro products. Various drying parameters like drying rate, moisture content, Specific Moisture Extraction Rate (SMER), Coefficient of Performance (COP), Exergy efficiency, and temperature as well as humidity conditions inside the drying chamber were also reviewed to promote the technological advancement of energy utilization by commercial cold storage waste heat recovery.     

Quantifying the Impact of Renewable Energy Futures on Cooling Water Use

This article presents an empirically based model, WiCTS ( Wi thdrawal and C onsumption for T hermoelectric S ystems), to estimate regional water withdrawals and consumption implied by any electricity generation portfolio. WiTCS uses water use rates, developed at the substate level, to predict water use by scaling the rates with predicted energy generation. The capability of WiCTS is demonstrated by assessing the impact of renewable electricity generation scenarios on water use in the United States (U.S.) through 2050. The energy generation scenarios are taken from the Renewable Energy Futures Study performed by the U.S. National Renewable Energy Laboratory of the U.S. Department of Energy. Results indicate reductions in water use are achieved under these renewable energy scenarios. The analysis further explores the impact of two modifications to the modeling framework. The first modification presumes geothermal and concentrated solar power generation technologies employ water‐intensive cooling systems vs. cooling technology that requires no water. The second modification presumes all water‐intensive cooling technologies use closed cycle cooling (as opposed to once‐through cooling) technologies by 2050. Results based on one of the renewable generation scenarios indicate water use increases by over 20% under the first modification, and water consumption increases by approximately 40% while water withdrawals decrease by over 85% under the second modification.     

多举措集成提升电厂节水减排成效

本着分级使用、减少排放、综合利用的原则,根据现场实际情况进行综合治理,重点是增加并完善梯级利用程度,提高水资源利用效率。对除灰、输煤废水这类浊度较大的废水进行自循环利用,禁止外排;完善循环水排污水利用系统;对高含盐量化学废水进行综合利用,达到既减排又可以改善废水水质的目的。     

Managing the cooling capacity of the upper rhine: A case study

In most industrialized countries, environmental standards exist which prescribe the maximum allowable man-made increase in water temperature of a river. Together with flowrate and weather conditions, these standards determine the rate at which waste heat may be discharged into a river at any moment. Power generating stations with variable cooling systems can adjust their heat discharge into the river in compliance with environmental standards and by doing so exert an influence on power generation capacity. In this paper, a scheme is developed that allows a chain of power stations discharging into the same river to operate their cooling systems such that the output of total electricity is maximized and water temperature standards are accomodated. The optimum balance between stations is determined through dynamic programming. From the results of a simulation model using historical data, simple decision rules for day-to-day operation are abstracted. These rules are based solely on the river flow rates at each power station.     

Regional industrial ecology: examples from regional economic systems of forest industry and energy supply in Finland

Industrial ecology (IE) promotes the development of industrial systems based on recycling of matter and cascading of energy through cooperation. In this paper, the local/regional industrial ecosystem approach is reflected in two examples from Finland. The local forest industry system is based on renewable resources, waste materials and energy utilisation between forestry companies, a saw-mill, a pulp mill, a paper mill and a forest industry power plant. Waste energy from electricity production is used for production of heat and process steam. Regional city energy supply systems in Finland are also to a large extent arranged around power plants that utilise waste energy. The potential of combining the forest industry system with the energy supply systems of cities is considered and the conditions for success in the Finnish case are discussed.     

三普2#地热站供热工程设计方案优化分析

通过分析地热供热的相关概念，建立了高效利用地热能源的一系列实现途径。根据工程的基础材料，从技术和经济方面对单纯地热供热方案、地热燃气调峰方案、热泵配置方案以及最终的组合方案进行了优化和调整，从而为三普2#地热井供热工程提供了优化方案，提高了该地区的地热利用率。     

秦皇岛地热能梯级利用状况与前景分析

在对秦皇岛地热能资源现状和开发利用调查的基础上,对秦皇岛地区的地热资源分布特征进行了分类,通过对相应的地热资源利用现状进行调查,掌握了地热能利用的现状以及存在的种种问题和不足。为了更加合理高效地利用地热能资源,进行开发利用前景分析,制定了地热能综合梯级利用的规划建议。     

Deployment of parabolic trough concentrated solar power plants in North Africa – a case study for Libya

The study addresses the potential of using concentrated solar power plants (CSPs) as a sustainable alternative of clean energy generation in the Mediterranean region and, in particular, in its North Africa shore. This location presents attractive conditions for the installation of CSPs, in particular high solar irradiation, good manpower concentration, and proximity and availability of water resources for condenser cooling. Energetic, exergetic, and economic analyses were conducted taking into consideration a particular type of CSPs - the parabolic trough concentrated solar power plant, which incorporates the most proven technology and it is already used in Southern Europe (Spain). In addition, the study considered the impact of project financing and incentives on the cost of energy. The combination of higher values for performance and potentially lower levelized cost of electricity (LCE) for the North Africa Mediterranean Rim than the South of Spain region can yield a very favorable return for the invested capital. Tripoli compared to Almeria presented superior performance and potentially lower LCE values ($0.18/kWh versus $0.22/kWh). This is significant, even when it is taken into consideration the fact that the plant in Tripoli, despite a relatively modest capacity factor of 34%, has a large gross power output of 173,886 MWhe. In addition, the implementation at the Tripoli location of a plant similar to the Anadsol plant has a slight advantage (2–3%) in terms of overall efficiency.     

畜粪污染处理与利用研究

国内外对于粪便固体物的处理主要采用焚烧法、干燥法和堆肥法等，在粪便污水处理方面主要采用厌氧消化法，它将治污、产气和综合利用相结合，使废物资源化，达到环境效益、经济效益和社会效益相统一。     

A Lifecycle Assessment and Economic Valuation of Recycling

The financial costs of recycling schemes fail to account for external costs and benefits such as environmental pollution, road congestion and accidents. This paper compares the environmental and social impacts of a kerbside collection scheme for recyclable household waste, with a bring scheme, using lifecycle assessment. Economic valuation is used to assign relative weights to these impacts. A second comparison examines the relative external costs of recycling and landfill disposal of waste. The results show that the kerbside collection scheme has a lower external cost than the bring scheme, but this is of less importance than the benefits to be gained within the manufacturing system by using secondary materials. It is concluded that the combination of lifecycle assessment and economic valuation is an effective means of evaluation to direct the sustainable development of waste management.     

精细化工厂污水排放控制措施

中原油田天然气产销总厂精细化工一厂为了实施清洁化生产,对污水外排从控制污水产生入手,采取了改冷却水一次排放为循环利用、化学处理改善水质及提高水的循环利用率等一系列措施,投入改造资金5万余元,将污水日排放量由1200 m3降到50 m3 ,且实现达标排放,取得了较好的经济效益和环境效益。     

The development of a UK kerbside scheme using known practice

Local authorities in the UK have been set challenging new targets for recycling household waste for 2003/4. This means many of them are urgently trying to determine which parameters in kerbside schemes are most important for increasing recycling rates. In this work information from previous kerbside schemes was used to plan significant improvements in an existing scheme in Horsham District, UK, and a trial was conducted using 1000 homes including a control group. It used fortnightly collection of residual waste with sets of recyclables collected on alternate weeks. The new scheme resulted in improvements of participation rates from 72 to 84%, and set-out rates from 45 to 59% (falling to 76 and 50% respectively, some months later). Details on participation and set-out for different groups of materials are given, as well as levels of excess waste and participation in the collection of garden waste.