联合循环中蒸汽底循环优化设计的方法与模型

1背景联合循环发电与联产系统已成为传统火电站强有力的竞争者，蒸汽底循环已成为联合循环的有机组成部分。高性能的燃气轮机要求高效率的底循环与之相匹配，以达到提高系统效率的最终目的。关于蒸汽底循环的设计，目前的方法可分为：案例分析【‘1、特定流程的特定方法［‘］、未实现梯级利用的压力匹配设计l’］。这些方法都未能对燃机排热实现有效的梯级利用，而且不能全面考虑底循环面对的限制。本文克服已有方法的局限性，提出底循环灵活、统一的模型，真实反映燃机排热最有效的梯级利用方式，适应不同联合循环对底循环的不同要求和实…     

环境温度对燃气轮机功热并供装置及联合循环变工况性能的影响

采用动力机械变工况性能解析分析方法,研究了大气温度变化对燃气轮机功热并供和联合循环装置性能影响．指出燃气轮机在带有余热利用的条件下,大气温度的影响明显减弱,并对不同燃气轮机设计参数和蒸汽设计参数影响做了分析比较。     

Energy conservation in the refinery by utilizing reformed fuel gas and furnace flue gases

Decrease of fuel supplies and cost increases make it vital for industries, especially energy intensive ones, to consider conserving available sources and convert losses into sources of energy.In this paper, a gas turbine-based cogeneration system is suggested to utilize a refinery's reformer gas in the gas turbine, and furnaces flue gases together with the engine exhaust gases in a heat recovery steam generator, HRSG. This is proposed as an alternative to the currently used system where the gas turbine and the steam generator are used separately. Operating variables comprising compressor pressure ratio and turbine inlet temperature are varied widely to evaluate performance; namely power, SFC, overall efficiency and annual fuel savings at design and off-design loading conditions using a dedicated computer program.Results show that the proposed system offers 100% higher overall efficiency and $5.25 million annual fuel saving for a 12 MW_e gas turbine.     

Refuse-fired,pressurized, fluidized-bed combustion combined cycle analysis

Use of pressurized, fluidized-bed combustion (PFBC) has given a new opportunity to use municipal refuse as fuel for combined gas and steam power cycles keeping the pollutants of sulphur and nitrogen oxides to a minimum at reduced capital cost.In combined gas and steam power cycles, the heat energy in the exhaust gases of a simple gas turbine cycle is used to generate steam in a waste-heat boiler and the generated steam is used in the steam turbine for power generation.The effects of gas turbine pressure ratio and inlet temperature on the main parameters of refuse-fired, pressurized, fluidized-bed combustion combined cycles are determined.The results indicate a maximum combined cycle thermal efficiency and work output at a possible range of optimum pressure ratios between 10 and 12 for a range of gas turbine inlet temperatures of 750–1000°C.     

Criteria for integration of combined cycle cogeneration systems in the process industries

Cogeneration systems often provide a very effective means of integrating power generation with the provision of thermal energy to an industrial process. Various types of power generating machines can be used, but combined cycle cogeneration systems can offer significant advantages over other technologies in many medium and large scale applications. The systems that are used consist of fired prime movers (usually gas turbines), discharging their exhaust heat into heat recovery steam generators. The steam raised in this way is passed through back-pressure steam turbines to extract additional power before finally delivering its residual heat content to process heating duties.This paper presents an overview of the economic trade-offs in the design of single cycle and combined cycle systems. Generalizations are derived from this investigation, leading to the identification of three distinct classes of problem for which different types of cogeneration systems (combined cycle or single cycle) are appropriate. Case study results are presented to illustrate the principles employed.     

Combined cycles with gas turbine engines

Simple cycle gas turbine engines suffer from limited efficiencies and consequential dominance of fuel prices on generation costs. Combined cycles, however, exploit the waste heat from exhaust gases to boost power output, resulting in overall efficiencies around 50%, which are significantly above those of steam power plants. This paper reviews various types of combined cycles, including repowering, integrated gasification and other advanced systems.     

Waste heat recovery of dura (Iraq) oil refinery and alternative cogeneration energy plant

The first part of this paper presents a waste heat recovery scheme for the Dura (Baghdad, Iraq) oil refinery energy plant. Both the wasted heat of the process return condensate and the flue gases are utilized for low temperature feedwater and fuel heating. The steam saved, both from the main steam line and turbine extraction system, was found to increase the steam and plant overall efficiency by 18%.An alternative cogeneration energy plant is presented in the second part of this study. The proposed plant utilizes the gas turbine exhaust, in conjunction with a heat recovery boiler, to produce the process steam requirement. With this alternative plant, the overall efficiency increases by 31.6%, while the steam efficiency increases by 19%. The outstanding features and advantages of the proposed plants are highlighted.     

Gas turbine exhaust gas heat recovery at South Baghdad (Iraq) power plant

Gas turbine exhaust is usually relatively clean, especially the exhaust from natural gas turbines. The use of such gases to improve the overall thermal efficiency of a steam power plant has the advantage of reducing the cost of cleaning the equipment and reducing the maintenance costs of the heat recovery equipment used in the application.In this paper, two proposals for recovering the waste energy of the exhaust gases from a gas turbine unit, fuelled by natural gas at south Baghdad Power Plant (Iraq) are discussed. The proposals cover improvements to the thermal efficiency of a steam power plant installed near the gas turbine unit. The first proposal is to use the exhaust gases to preheat the feed water at four feed water heaters, in order to increase the power output. This arises because of the savings in the amount of steam extracted at a different level used for preheating the feed water line. The second proposal is to use the thermal energy in the exhaust gases to reheat the extracted stream, at five points at a high thermal potential, to increase the thermal gain at the preheating feed water line. This avoids the complexity associated with rejection of the extracted steam. The first roposal shows that a 1.22–14.9% saving in fuel consumption is achievable and the overall thermal efficiency of the steam power plant becomes 29–34% (at different gas turbine plant loads). The second proposal shows that a 2.3–7.35% saving in fuel consumption can be attained and the corresponding thermal efficiency will be 30.3–32%.     

Gas turbine waste heat recovery distillation system

This article presents a method for improving the gas turbine's performance through an efficient utilization of the waste heat in a distillation system with a special arrangement. This consists of two trains of VTE/MEB connected to increase the fresh water produced. Exhaust gases from the gas turbine are used in a multi-temperature level heat recovery system with five feed heaters, and gases are released to ambient at 130°C. Distillation top train has nine effects and evaporation range from 130 to 82°C while the bottom train has six effects with evaporation range from 76 to 46°C and is supplied with the steam leaves the last effect in the top train.Thermal analysis using a 32.67 MW gas turbine showed that the present arrangement can produce 3.2 million gallons per day (mgd) of fresh water with more than 4 g/kWh at a performance ratio (PR) of 8.8. This is 34% more than that produced in an existing gas-turbine distillation combination and 14% more than that expected from a reverse osmosis plant driven by a bottoming Rankine power cycle.     

Development and Analysis of the Novel Hybridization of a Single-Flash Geothermal Power Plant with Biomass Driven sCO2-Steam Rankine Combined Cycle

This study investigates the hybridization scenario of a single-flash geothermal power plant with a biomass-driven sCO₂-steam Rankine combined cycle, where a solid local biomass source, olive residue, is used as a fuel. The hybrid power plant is modeled using the simulation software EBSILON^®Professional. A topping sCO₂ cycle is chosen due to its potential for flexible electricity generation. A synergy between the topping sCO₂ and bottoming steam Rankine cycles is achieved by a good temperature match between the coupling heat exchanger, where the waste heat from the topping cycle is utilized in the bottoming cycle. The high-temperature heat addition problem, common in sCO₂ cycles, is also eliminated by utilizing the heat in the flue gas in the bottoming cycle. Combined cycle thermal efficiency and a biomass-to-electricity conversion efficiency of 24.9% and 22.4% are achieved, respectively. The corresponding fuel consumption of the hybridized plant is found to be 2.2 kg/s.     

Computer simulation of a combined cycle power plant

This paper presents the simulation procedure developed to predict the performance of a combined cycle power plant from given performance characteristics of its main components. In order that the procedure could be validated, the simulation technique has been applied to a typical combined cycle power plant (having a dual pressure bottoming cycle) manufactured by a prominent company. The characteristics of the standard equipment like the air compressor, steam and gas turbines, various pumps, etc. have been taken from the manufacturer's catalogues and converted into appropriate equations based on theoretical understanding. The performance of various heat exchangers (like economizers, superheaters, evaporators, etc.) has been determined by using the effectiveness concept after evaluating the overall heat transfer coefficient by using appropriate correlations from literature. The strategy of system simulation is obtained by judiciously interlinking the information flow diagrams of various components and thus the task is finally reduced to that of solving nine non-linear equations for nine variables. The predicted performance of the system is seen to be in good agreement with in good agreement with its rated performance.     

Coordinated optimization of the parameters of the cooled gas-turbine flow path and the parameters of gas-turbine cycles and combined-cycle power plants

In the present paper, we evaluate the effectiveness of the coordinated solution to the optimization problem for the parameters of cycles in gas turbine and combined cycle power plants and to the optimization problem for the gas-turbine flow path parameters within an integral complex problem. We report comparative data for optimizations of the combined cycle power plant at coordinated and separate optimizations, when, first, the gas turbine and, then, the steam part of a combined cycle plant is optimized. The comparative data are presented in terms of economic indicators, energy-effectiveness characteristics, and specific costs. Models that were used in the present study for calculating the flow path enable taking into account, as a factor influencing the economic and energy effectiveness of the power plant, the heat stability of alloys from which the nozzle and rotor blades of gas-turbine stages are made.     

Enhancing gas turbine performance by intake air cooling using an absorption chiller

The performance of gas turbines, operated either as a simple cycle or a combined cycle, is critically constrained by the prevailing ambient temperature, particularly in arid and tropical climates. This paper investigates the option of cooling the intake air to the compressor of the gas-turbine system using an absorption chiller in order to increase the gas turbine capacity. High-temperature waste heat from the exhaust gas may be utilized to produce steam in a recovery boiler. Part of the steam produced could then be used to drive a lithium-bromide double-effect absorption chiller which in turn could cool the incoming air. An analysis carried out by taking the weather data of Bangkok (Thailand) indicates that reducing the temperature from ambient condition to 15°C could help to increase the instantaneous power output between 8 and 13%. As an outcome, as much as 11% additional electricity could be generated from the same gas turbine power plant.A simple economic assessment indicates that the proposed scheme will require a minimal investment as compared to the commissioning cost of a new gas turbine unit to meet the corresponding capacity increment. The latter will need nearly four times higher initial cost than the amount estimated for the proposed scheme. Thus, implementation of such a system would significantly abate the negative impact of the ambient temperature, while providing an economically and environmentally attractive option for energy producers in most developing nations of the world which are located in arid and tropical zones.     

Thermal performance of waste-heat recuperator with heat pipes for thermal power station

Analytical studies were conducted to investigate the thermal performance of a heat pipe heat exchanger to recover thermal energy from exhaust hot gas from a boiler, in order to replace a conventional heat recovery system (Ljungstrom) in the steam power plant.     

Fuel cost charged to desalters in co-generation power-desalting plants

In combined power-desalting (plants, high available steam (at high pressure temperature) is expanded first in a steam turbine (and thus produces work) before its extraction (from the turbine) as a heat source to the desalters. The amount of energy consumption charged to the predominantly used multi-stage flash (MSF) desalter in this combined heat and power plant is a question of great concern in the Gulf area. The following are among the methods used to answer this questions (i) the available energy of the heat supplied to the desalter; (ii) work loss from the lower pressure stages of the steam turbine due to steam extracted to the desalter; (iii) energy charged if a separate boiler was used to supply the desalter with its required heat; and (iv) the excess energy supplied to the combined power desalting plant as compared to a single purpose power plant producing the same power output. There would be a different rating method of the power producing process associated with any of the above mentioned charging methods. In this paper, the MSF desalting method and its power consumption are outlined, together with the rating method of the power-desalting plants and the energy charged to the desalter methods. These rating methods are applied to real cases of dual purpose plants working in Kuwait.     

排气全燃型联合循环设计点性能简明估计公式

排气全燃型联合循环设计点性能简明估计公式蔡睿贤（中国科学院工程热物理研究所北京１０Ｏ０８０）关键词：排气全燃型联合循环，热力分析主要符号表Ｈｕ燃料热值Ｌ燃料理论空气量ｌ比功Ｐ单位能量价格Ｒ燃气轮机与蒸汽轮机的功率比α过量空气系数β摩尔燃料系数△增量η...     

400MW级IGCC机组变工况性能计算

1引言一个多世纪以来,煤一直是世界上主要的发电燃料,这一趋势将在较长的时间内一直保持下去。对于中国这样一个以煤作为一次能源的国家,这一现象尤为突出。特别是随着全球性能源危机的出现以及环境保护要求的提高,使得洁净煤技术（CCT）受到普遍关注。在众多的洁净煤发电技术中,IGCC技术以其特有的高效率、低污染等特点,被认为是下世纪最有发展前途的洁净煤发电技术之一。鉴于IGCC系统结构与组态非常复杂,涉及煤的气化、净化、燃气轮机、余热锅炉、蒸汽轮机、空气分离等关键技术,因此建立IGCC系统的性能模型,对IGCC机组的…     

The gas turbine-jet pump coupling in cogeneration plants

When a steam driven jet pump is coupled to a gas turbine it can decrease the exhaust total pressure of the turbine and thus increase its output and the gas turbine thermal efficiency. If the steam is generated in a waste heat recovery the thermal efficiency of the engine may increase by 2–3%. The present paper studies the gas turbine-jet pump coupling, at various partial loads, by incorporating the long exhaust diffuser as a water preheater. In addition, additional firing may be introduced at the boiler inlet to keep the temperatures of the boiler constant. The results indicate that the efficiency of the gas turbine increases by 3–4% at optimum conditions.     

给水加热型联合循环的变工况性能

在联合循环改造的各种方案中,给水加热型具有投资少、改动少、耗用优质燃料较少、尤其是简单易行及技术难度小等特点,因此在我国现有的技术经济水平、特别是以煤为主的国情下,有一定应用市场。本文分析比较了多种变工况运行方式的性能及可能出现的问题,并在此基础上提出综合性能较好的运行模式。     

The key role of heat exchangers in advanced gas-cooled reactor plants

The use of helium as a nuclear reactor coolant has been successfully demonstrated in plants built and operated in the U.K., U.S.A., and Germany. Following the pioneering proof of principle plant, two small power plants were operated for several years and this led to the construction of two commercial power stations. For the next generation of gas-cooled reactors new criteria have been developed, namely, the plants will be smaller, simpler, safer and of lower cost. The base case Modular High-Temperature Gas-Cooled Reactor (MHTGR) utilizes existing technology to offer a tried and proven power generating plant using a conventional steam turbine power conversion system that could be in utility service just after the turn of the century. The capability of the MHTGR to operate at very high temperatures will be exploited early in the next century in the form of advanced variants to meet the needs of the power generation and process industries. A key component in the MHTGR is the heat exchanger, since this is where the reactor thermal energy is transferred to the prime-mover or process system. This paper addresses the various roles that heat exchangers will play in advanced MHTGRs, recognizing that the requirements for the steam cycle, gas turbine (direct- or indirect-cycle), and process heat reactor are unique. Topics include thermodynamic considerations, differing configurations, and construction types; materials (metals, composites, ceramics); germane technology bases; and advanced heat exchanger technologies.