超超临界机组喷水减温系统的热经济性分析

针对超超临界机组过热器、再热器喷水减温机理进行了分析,以引进型1 000MW机组为例,运用现行矩阵分析方法,经过严密的数学推导,建立了过热器、再热器减温喷水对机组热经济性影响的计算模型,对过热器和再热器喷水减温系统对机组热经济性的影响进行了定量分析.分析得出再热器喷水减温对机组经济性的影响比过热器喷水减温的影响要大得多.再热器最小喷水减温量的热经济性比过热器允许最大喷水减温量的热经济性还要差,运行时应尽量减少或避免采用再热器喷水减温.     

蒸汽调温方式对机组经济性的影响分析

定量分析了200MW、300MW、600MW机组喷水调温系统对机组热经济性的影响,指出过热蒸汽喷水调温系统的减温水应由最高一级加热器出口引出,不仅可以提高机组的热经济性,且可以缩短减温水管道的长度,方便管道布置,减少投资。再热蒸汽喷水调温对机组热经济性的影响较大,机组实际循环热效率降低较多,运行时应尽量减少或避免再热汽温采用喷水调节。     

喷水减温对机组热经济性的影响

以200MW、300 MW、600 MW机组为例,定量分析了过热器和再热器喷水调温系统对机组热经济性的影响,指出过热器喷水调温系统的减温水应由最高一级加热器出口引出,不仅可以提高机组的热经济性,且可以缩短减温水管道的长度,方便管道布置,减少投资.再热器喷水调温对机组热经济性的影响较大,机组实际循环热效率降低较多,运行时应尽量减少或避免再热汽温,采用喷水调节.     

垃圾焚烧余热锅炉过热器喷水减温系统的技术改造

厦门后坑垃圾焚烧发电厂余热锅炉过热器喷水减温系统,因原设计及减温水调节阀性能等因素导致锅炉主蒸汽温度自动控制失调,为此对喷水减温系统进行了技术改造,解决了主蒸汽温度失调的问题,最终达到锅炉安全运行的目的。     

喷水减温系统改造及经济性分析

某电厂喷水减温系统具有较大节能潜力,对喷水减温系统进行了改造,过热减温水由目前的给水泵出口母管引接,改为由高加出口给水母管引接。为了确定过热减温水系统改造后的经济性变化,采用热力系统建模方法进行了不同运行工况的计算。结果表明负荷在330~660 MW负荷变化范围内,经技术改造后供电煤耗平均降低值在0.80 g/k W·h以上,净热耗率的降低值随着负荷的升高呈增大趋势,机组负荷越高,由减温水变化导致的机组出力下降越多。     

燃气轮机进气制冷装置的理论依据和实际效能

从燃气轮机的循环比功和有用功系数的理论分析可知，降低燃气轮机进气温度，对提高燃气轮机出力和热效率起到事半功倍的作用。深圳金岗电厂ＰＧ６５３１Ｂ型５０ＭＷ燃气－蒸汽联合循环机组，利用余热锅炉烟气的余热采用溴化锂制冷机组，降低燃气轮机进气温度，使联合循环机组实际出力提高３５００ｋＷ，热效率提高２％，取得了可观的经济效益。     

超临界机组主蒸汽温度控制策略研究

燃煤超临界机组主汽温度控制在湿态时通过喷水减温进行调节;干态时通过中间点温度对水煤比进行粗调,提高主汽温控制的稳定性,再通过喷水减温进行细调,保证主汽温与设定值偏差在允许范围内。某电厂#1、#2机组(2×630MW)主汽温度喷水减温控制长期不能投入自动控制,只通过运行人员手动调整,由于手动调整的局限性和同时需防止主汽温度超温,因此主汽温度长期控制在额定温度以下运行,在机组变负荷工况、启停磨及煤质波动情况下容易出现超温及较低主汽温运行,不利于机组的安全和经济运行。     

电站锅炉再热蒸汽温度的燃烧器摆角和喷水减温协调预测控制

针对目前再热汽温控制系统中存在的局限性,从控制算法和切换逻辑2个方面对锅炉再热蒸汽温度控制进行改进,设计了一种使用燃烧器摆角和喷水减温作为再热蒸汽温度调节手段的协调预测控制方法,并将改进后的方法与常规预测控制和串级PID控制进行对比。结果表明:所提出的预测控制方法能实现燃烧器摆角和喷水减温控制的平滑无扰切换,提高了系统的调节性能和稳定性,大大减少了燃烧器摆角调节系统与喷水减温调节系统之间的来回切换次数。     

生物质气微型燃气轮机运行性能分析

为研究生物质气微型燃气轮机的运行性能,构建了微型燃气轮机模型。基于C60微型燃气轮机的设计数据,首先以天然气为燃料,验证了模型的合理性。然后以沼气、松木气和干牛粪气等生物质气为燃料,在机组输出功率为60 kW及燃烧室出口温度为1 145 K两个工况分别得到燃气轮机的主要输出参数。结果表明：维持燃气轮机输出功率为60 kW时,所需生物质气流量增大,燃烧室出口温度降低,压比增大,压气机耗功减少,机组效率提高;维持燃烧室出口温度为1 145 K,燃料流量增加,引起燃气流量增大,透平的输出功增多,机组输出功率和机组效率增大;燃料初温从300 K升高到700 K,当保持额定输出功率时随着燃料初温上升机组热效率增大;当保持额定燃烧室出口温度时,随着燃料初温上升燃料流量减少,机组输出功率和机组热效率降低。     

喷水减温调节阀的试验与研究

将DN32 ;PN2 5直线特性喷水减温调节阀和DN2 0 ;PN2 5抛物线特性喷水减温调节阀进行了对比试验 ,并对试验数据进行了分析与研究 ,得出锅炉减温系统喷水调节阀的设计依据     

Analysis of gas turbine operating parameters with inlet fogging and wet compression processes

Inlet fogging has been widely noticed in recent years as a method of gas turbine air inlet cooling for increasing the power output in gas turbines and combined cycle power plants. The effects of evaporative cooling on gas turbine performance were studied in this paper. Evaporative cooling process occurs in both compressor inlet duct (inlet fogging) and inside the compressor (wet compression). By predicting the reduction in compressor discharge air temperature, the modeling results were compared with the corresponding results reported in literature and an acceptable difference percent point was found in this comparison. Then, the effects of both evaporative cooling in inlet duct, and wet compression in compressor, on the power output, turbine exhaust temperature, and cycle efficiency of 16 models of gas turbines categorized in four A–D classes of power output, were investigated. The results of this analysis for saturated inlet fogging as well as 1% and 2% overspray are reported and the prediction equations for the amount of actual increased net power output of various gas turbine nominal power output are proposed. Furthermore the change in values of physical parameters and moving the compressor operating point towards the surge line in compressor map was investigated in inlet fogging and wet compression processes.     

Improvement of part-load performance of gas turbine by adjusting compressor inlet air temperature and IGV opening

A novel adjusting method for improving gas turbine (GT) efficiency and surge margin (SM) under part-load conditions is proposed. This method adopts the inlet air heating technology, which uses the waste heat of low-grade heat source and the inlet guide vane (IGV) opening adjustment. Moreover, the regulation rules of the compressor inlet air temperature and the IGV opening are studied comprehensively to optimize GT performance. A model and calculation method for an equilibrium running line is adopted based on the characteristic curves of the compressor and turbine. The equilibrium running lines calculated through the calculation method involve three part-load conditions and three IGV openings with different inlet air temperatures. The results show that there is an optimal matching relationship between IGV opening and inlet air temperature. For the best GT performance of a given load, the IGV could be adjusted according to inlet air temperature. In addition, inlet air heating has a considerable potential for the improvement of part-load performance of GT due to the increase in compressor efficiency, combustion efficiency, and turbine efficiency as well as turbine inlet temperature, when inlet air temperature is lower than the optimal value with different IGV openings. Further, when the IGV is in a full opening state and an optimal inlet air temperature is achieved by using the inlet air heating technology, GT efficiency and SM can be obviously higher than other IGV openings. The IGV can be left unadjusted, even when the load is as low as 50%. These findings indicate that inlet air heating has a great potential to replace the IGV to regulate load because GT efficiency and SM can be remarkably improved, which is different from the traditional viewpoints.     

Analysis of parameters affecting the performance of gas turbines and combined cycle plants with vapor absorption inlet air cooling

The integration of an aqua‐ammonia inlet air‐cooling scheme to a cooled gas turbine‐based combined cycle has been analyzed. The heat energy of the exhaust gas prior to the exit of the heat recovery steam generator has been chosen to power the inlet air‐cooling system. Dual pressure reheat heat recovery steam generator is chosen as the combined cycle configuration. Air film cooling has been adopted as the cooling technique for gas turbine blades. A parametric study of the effect of compressor–pressure ratio, compressor inlet temperature, turbine inlet temperature, ambient relative humidity, and ambient temperature on performance parameters of plants has been carried out. It has been observed that vapor absorption inlet air cooling improves the efficiency of gas turbine by upto 7.48% and specific work by more than 18%, respectively. However, on the adoption of this scheme for combined cycles, the plant efficiency has been observed to be adversely affected, although the addition of absorption inlet air cooling results in an increase in plant output by more than 7%. The optimum value of compressor inlet temperature for maximum specific work output has been observed to be 25 °C for the chosen set of conditions. Further reduction of compressor inlet temperature below this optimum value has been observed to adversely affect plant efficiency. Copyright © 2013 John Wiley & Sons, Ltd.     

Effects of evaporative inlet and aftercooling on the recuperated gas turbine cycle

Inlet air cooling and cooling of the compressor discharge using water injection boost both efficiency and power of gas turbine cycles. Four different layouts of the recuperated gas turbine cycle are presented. Those layouts include the effect of evaporative inlet and aftercooling (evaporative cooling of the compressor discharge). A parametric study of the effect of turbine inlet temperature (TIT), ambient temperature, and relative humidity on the performance of all four layouts is investigated. The results indicate that as TIT increases the optimum pressure ratio increases by 0.45 per 100 K for the regular recuperated cycle and by 1.4 per 100 K for the recuperated cycle with evaporative aftercooling. The cycles with evaporative aftercooling have distinctive pattern of performance curves and higher values of optimum pressure ratios. The results also showed that evaporative cooling of the inlet air could boost the efficiency by up to 3.2% and that evaporative aftercooling could increase the power by up to about 110% and cycle efficiency by up to 16%.     

Thermo‐economic Optimization of Gas Turbine Power Plant with Details in Intercooler

In this paper a gas turbine power plant with intercooler is modeled and optimized. The intercooler is modeled in details using the ε ? NTU method. Air compressor pressure ratio, compressor isentropic efficiency, gas turbine isentropic efficiency, turbine inlet temperature, cooling capacity of the absorption chiller, recuperator effectiveness as well as eight parameters for configuration of the intercooler are selected as design variables. Multi‐objective genetic algorithm is applied to optimize the total cost rate and total cycle efficiency simultaneously. Two plants including an intercooler and with/without air preheater are studied separately. It is observed that the air compressor pressure ratio in the HP compressor is higher than the LP compressor in both cases and its differences are higher for a plant without an air preheater. Actually the air compressor pressure ratio is found to be about 8.5% lower than the ideal value and 9.5% higher than the ideal value in the LP compressor and HP compressor, respectively, in the case with an air preheater. Moreover, a correlation for intercooler pressure drop in terms of its effectiveness was derived in the optimum situation for each case. © 2013 Wiley Periodicals, Inc. Heat Trans Asian Res, 42(8): 704–723, 2013; Published online in Wiley Online Library ( wileyonlinelibrary.com/journal/htj ). DOI 10.1002/htj.21051     

某型燃气轮机试验台进气盐雾系统设计及试验验证研究

为满足燃气轮机试验台配置模拟海洋大气环境装置的需求,设计了试验台盐雾系统。该系统通过蠕动泵输送燃气轮机各工况所需要的盐溶液,盐溶液输送至雾化器内雾化后形成盐雾,盐雾在燃气轮机进气道中与燃气轮机吸入的空气混合后进入压气机。在20%,35%,50%,60%,80%和100%等额定功率工况下对压气机进口空气含盐质量分数进行测量计算,压气机进气含盐质量分数均约为0.01×10-6,验证了系统满足燃气轮机全功率工况空气含盐质量分数的模拟要求。     

MAT, a novel, open cycle gas turbine for power augmentation

A Moisture Air Turbine (MAT) cycle is proposed for improving the characteristics of land-based gas turbines by injecting atomized water through an inlet into a compressor. Compressor work of isentropic compression for moist air mixtures with phase change is theoretically considered, which has revealed that water evaporation may reduce compressor work. An experiment using a 15 MW class axial flow load compressor has also verified the theory. Realistic cycle model calculations predict that a 10% power increment by a ratio of 1% water to compressor intake air is expected and also that the amount of water consumption is much less than that of conventional inlet air cooling systems, used for heat rejection at the cooling tower. In addition, thermal efficiency is anticipated to be improved mainly due to the reduction of compressor work. Contrary to the conventional evaporative cooler, a MAT cycle could provide power output at a desired value within its capability regardless of ambient humidity condition.     

Power and efficiency optimization for combined Brayton and inverse Brayton cycles

A thermodynamic model for open combined Brayton and inverse Brayton cycles is established considering the pressure drops of the working fluid along the flow processes and the size constraints of the real power plant using finite time thermodynamics in this paper. There are 11 flow resistances encountered by the gas stream for the combined Brayton and inverse Brayton cycles. Four of these, the friction through the blades and vanes of the compressors and the turbines, are related to the isentropic efficiencies. The remaining flow resistances are always present because of the changes in flow cross-section at the compressor inlet of the top cycle, combustion inlet and outlet, turbine outlet of the top cycle, turbine outlet of the bottom cycle, heat exchanger inlet, and compressor inlet of the bottom cycle. These resistances control the air flow rate and the net power output. The relative pressure drops associated with the flow through various cross-sectional areas are derived as functions of the compressor inlet relative pressure drop of the top cycle. The analytical formulae about the relations between power output, thermal conversion efficiency, and the compressor pressure ratio of the top cycle are derived with the 11 pressure drop losses in the intake, compression, combustion, expansion, and flow process in the piping, the heat transfer loss to the ambient, the irreversible compression and expansion losses in the compressors and the turbines, and the irreversible combustion loss in the combustion chamber. The performance of the model cycle is optimized by adjusting the compressor inlet pressure of the bottom cycle, the air mass flow rate and the distribution of pressure losses along the flow path. It is shown that the power output has a maximum with respect to the compressor inlet pressure of the bottom cycle, the air mass flow rate or any of the overall pressure drops, and the maximized power output has an additional maximum with respect to the compressor pressure ratio of the top cycle. When the optimization is performed with the constraints of a fixed fuel flow rate and the power plant size, the power output and efficiency can be maximized again by properly allocating the fixed overall flow area among the compressor inlet of the top cycle and the turbine outlet of the bottom cycle.     

开式燃气轮机中冷回热再热循环功率和效率优化

建立了开式燃气轮机中冷回热再热（ICRR）循环有限时间热力学模型,导出了循环功率和效率解析式,优化了气流沿通流部分的压降（或低压压气机进口空气质量流率）和中间压比,得到最大功率;并在给定燃油流率的情况下,优化了气流沿通流部分的压降和中间压比,得到最大热效率,进一步在给定低压压气机进口和动力涡轮出口总面积的情况下,优化两者面积分配比,得到双重最大热效率.     

Simulation of a new biomass integrated gasification combined cycle (BIGCC) power generation system using Aspen Plus: Performance analysis and energetic assessment

A new biomass integrated gasification combined cycle (BIGCC), which featured an innovative two-stage enriched air gasification system coupling a fluidized bed with a swirl-melting furnace, was proposed and built for clean and efficient biomass utilization. The performance of biomass gasification and power generation under various operating conditions was assessed using a comprehensive Aspen Plus model for system optimization. The model was validated by pilot-scale experimental data and gas turbine regulations, showing good agreement. Parameters including oxygen percentage of enriched air (OP), gasification temperature, excess air ratio and compressor pressure ratio were studied for BIGCC optimization. Results showed that increase OP could effectively improve syngas quality and two-stage gasification efficiency, enhancing the gas turbine inlet and outlet temperature. The maximum BIGCC fuel utilization efficiency could be obtained at OP of 40%. Increasing gasification temperature showed a negative effect on the two-stage gasification performance. For efficient BIGCC operation, the excess air ratio should be below 3.5 to maintain a designed gas turbine inlet temperature. Modest increase of compressor pressure ratio favored the power generation. Finally, the BIGCC energy analysis further proved the rationality of system design and sufficient utilization of biomass energy.