Biomass co-firing in a pressurized fluidized bed combustion (PFBC) combined cycle power plant: A techno-environmental assessment based on computational simulations

The co-utilization of coal with biomass and biomass waste in a pressurized fluidized bed combustion (PFBC) system is a promising power generation option for addressing various areas of concern relating to the anthropogenic sources of harmful emissions, the global reliance on fossil fuel and the overall energy supply issues. In this study, coal with a wide range of biomass and biomass waste types such as straw, willow chips and switch grass as well as miscanthus and olive pits are fired in an advanced PFBC system. The produced gases and the evolved heat energy are employed to run a combined cycle. To understand the behavior of the proposed system, detailed computational simulations are carried out utilizing various feedstock mixtures ranging from 100% coal to 40% biomass. The results of the simulations are used to show the effect of co-firing on the technical and environmental performance of the power plant.The results show that the main parameters affecting the overall power plant efficiency are the co-firing ratios and the specific properties of the chosen biomass/waste types. Furthermore, the investigation indicates that the steam cycle output reacts more sensitive to the fuel configurations than the gas turbine cycle. As expected, the increased fraction of biomass or waste significantly reduces net CO₂ emissions, and has a beneficial influence on SO_x emissions. NO_x emissions tend to rise for all biomass types, except the high moisture content willow chips, with increasing co-firing fraction.     

喷雾干燥系统的经济优化研究

对三环节　经济优化能量综合方法在喷雾干燥系统的应用进行了全面深入的研究,提出了适用于喷雾干燥系统的　经济调优法;改进了喷雾干燥器的ＰＡＲＴＩ模型,使之能够方便快捷地进行模拟计算;以干燥尾气为决策变量,在一定　经济边界条件Ｇ＿（ｕｉ）和Ｃ＿（ｕｊ）下,给出了喷雾干燥塔的　经济优化计算方法。工业实际用例数据表明,该法实用、思路清楚且运算速度快。     

Performance assessment of a fixed-bed gasification pilot plant for combined power generation and hydrogen production

Large-scale hydrogen production through near zero emissions gasification plants represents a reliable technology which is being seriously considered for its potential economical implications. However, the application of these technologies is currently subject to high capital and operating costs. This needs great scientific and technical effort to optimize the processes and the equipment, to reduce the hydrogen production cost.In this context, a flexible and fully equipped pilot platform has been built up in the Sotacarbo Research Centre, in order to study several integrated gasification and syngas treatment process configurations for a CO₂-free combined production of hydrogen and electrical energy, to be used in medium and small-scale commercial plants. The platform includes pilot scale fixed-bed up-draft gasifiers, equipped with a flexible and complete syngas treatment line.This paper reports the main results obtained in the pilot plant during the last experimental campaign which has been carried out to improve the plant performance. In particular, a series of experimental tests has been performed in order to optimize the coal gasification process in different operating conditions. Moreover, a mention of the overall plant performance, based on the experimental results, has been presented, with particular reference to hydrogen, carbon and pollutant emissions.     

有机朗肯循环发电系统的多目标参数优化

建立以热回收率及单位输出功率所需换热面积为目标的多目标优化模型,利用模拟退火算法对循环采用R123、R236ea、R245fa、R227ea、R600等五种工质时的参数进行优化计算。结果表明:采用多目标优化模型可以协调各评价指标间的关系,更好地满足工程实际的需求;热源温度为140℃、循环采用R123时,最佳蒸发压力为0.69 MPa、冷凝压力为0.11 MPa,最佳蒸发压力随着冷凝压力的升高而增大;当管内流速超过0.5 m·s^-1时,流速对系统性能的影响较小。蒸发器内的最小传热温差为15℃。随着热源温度升高,循环的最佳蒸发压力增大。在分析的几种工质中,热源温度在100~220℃时,循环采用R123时性能最佳。     

LNG燃气电厂三联产系统节能分析

根据厦门燃气电厂实际情况,提出了一种LNG热电冷三联产节能方案。在假设条件下,分析并计算了该方案下的系统能源利用率、运行经济性及节能潜力。结果表明：该节能方案冷电、热电系统能源利用率分别可达89.2%和82.8%,联产系统总能利用率超过80%;而且供冷系统的运行费用较低,投资回收期小于5年,具有明显的经济效益和较大的节能潜力。     

基于建筑负荷的微型热电联产系统性能分析

微型热电联产是节能减排的有效途径。主要针对微型热电联产系统,通过设定参照对象建立热力学模型分析用能效果,并在微型热电联产机组匹配用户负荷条件下分析用户热电比及电网购电比例对联产系统节能潜力的影响。同时结合实测某办公楼供热季度的热电负荷特征确定微型热电联产系统方案,计算发现供热季联供方式日均节能率可达22.76%~23.16%,联供系统中原动机的效率可达48.06%。     

基于SOFC/GT/TCO2复合动力循环和溴化锂制冷机的冷热电联供系统性能

提出了一种新型冷热电联供系统,通过TCO₂循环和溴化锂制冷机回收SOFC/GT循环的排烟余热,实现对外供冷、供热和供电。建立了联供系统热力性能的数学模型,对系统进行了能量分析和（火用）分析,并研究了空燃比、SOFC压力、CO₂工质流率、CO₂工质分流比和TCO₂泵出口压力对系统性能的影响。研究结果表明,在额定工况下,系统的净发电效率为70.79%,系统总（火用）效率为68.29%,综合能源利用率为108.5%。增大空燃比、CO₂工质分流比或降低SOFC工作压力、CO₂工质流率和TCO₂泵出口压力可提高联供系统的综合能源利用率;增大SOFC工作压力、TCO₂泵出口压力或降低空燃比可提高联供系统的净发电效率和总（火用）效率,随CO₂工质流率和CO₂工质分流比的增大,净发电效率和总（火用）效率先降低后增大。     

有机朗肯循环热电联供系统的实验研究

有机朗肯循环低温热力循环性能优越,易于小型化和自动运行,非常适合于分布式热电联供系统。依托已有的ORC-CHP实验平台,对热源温度101℃,膨胀机乏汽余热利用温度21.6～48.7℃时系统的热力性能进行了实验研究。在该温度范围内,ORC-CHP系统的综合能量效率96%～97%,其中热功转换效率4.4%～5.1%,乏汽余热利用效率91%～92%;从可用能角度出发,系统综合可用能效率50.0%～75.3%,其中热功可用能效率24.4%～19.2%,乏汽余热可用能效率25.7%～56.2%。实验表明该系统可以高效利用膨胀机乏汽余热,明显提高了有机朗肯循环的综合利用效率。     

基于遗传算法和粒子群优化算法的电力系统无功优化

从数学的角度分析,电力系统无功优化是一个多变量、多约束、非连续性的混合非线性规划问题,因此,优化过程十分复杂.以减少有功网损为目标函数建立电力系统无功优化计算的数学模型,基于遗传算法和粒子群优化算法,提出一种新颖的混合策略来求解无功优化问题.IEEE 6和IEEE 14节点系统的仿真计算结果表明:与单一的遗传算法或粒子群优化算法相比,该混合策略在优化效果方面具有明显的优势.     

装置蒸汽动力系统与热电厂运行同步优化

石化企业装置蒸汽动力系统通常独立设计和操作,忽视了与热电厂蒸汽动力系统的联系。热电厂蒸汽动力系统通常在固定的蒸汽和电力需求下进行优化,忽视了与装置蒸汽动力系统的联系。为实现石化企业蒸汽动力系统的全局优化,本文提出了用于装置蒸汽动力系统与热电厂运行同步优化的方法。首先使用热电厂透平和锅炉的设计及运行数据回归得到设备模型系数,依照现有结构建立热电厂蒸汽动力系统约束。然后以装置蒸汽动力系统设计和操作灵活性为区分,将装置分为三类：第一类装置蒸汽和电力需求无法调节;第二类装置可以通过减温减压调节蒸汽需求;第三类装置既可以通过减温减压调节蒸汽需求,也可以通过驱动选择调节热电需求。装置透平模型参数采用文献值,通过采集各类装置蒸汽和电力需求等数据建立装置蒸汽动力系统约束,最后通过热电厂与装置蒸汽和电力的连接关系建立耦合模型。耦合模型以年度费用为目标函数,其中包括热电厂运行费用以及装置透平和电机的年度投资费用,通过优化求解得到热电厂设备负荷分配方案以及装置蒸汽动力系统设计方案。通过算例论证了同步优化方法的可行性,与独立优化相比,同步优化降低年度费用451万美元。     

Life cycle assessment to evaluate the green house gas emission from oil palm bio-oil based power plant

The objective of this study is to assess the green house gas (GHG) emission for the production of bio-oil from oil palm biomass and its utilization for 10 MW power generation by evaluating the life cycle carbon footprint analysis. The life cycle GHG emission assessment includes four main stages, which cover the oil-palm cultivation, palm oil mill operation, biomass transportation and pyrolysis process for the production of bio-oil and its utilization for 10MW power generation. The results obtained suggest that the palm bio-oil has potential as a carbon neutral renewable energy source in the future. More importantly, it has no negative impact on the environment as the amount of CO₂ emitted to the atmosphere during combustion of this fuel is lower than that of the CO₂ absorbed from the atmosphere during cultivation stage.     

Cost optimization of a combined power and water desalination plant with exergetic,environment and reliability consideration

The present study deals with the multi-objective optimization for designing a combined gas turbine and multi stage flash desalination plant. In optimization approach, the exergetic, economic and environmental aspects have been considered, simultaneously. In order to achieve the optimal design, Multi-objective genetic algorithm (MOGA) is applied as a suitable optimization technique. The thermoenvironomic objective function is obtained by integrating the environmental impacts and thermoeconomic objective. By applying the optimization approach, this objective function is minimized, whereas system exergy efficiency is maximized. Moreover, equipment reliability using the state-space and the continuous Markov method is incorporated in optimization results to improve the products' cost values. The optimization results show that the cost of products and environmental cost impact are reduced by 13.4% and 53.4%, respectively, whereas a 14.8% increase happens in total exergy efficiency. Therefore, improvement in all objectives has been achieved using the optimization process, although the power and water productions have not changed much. Additionally, the sensitivity analysis shows the relationship between the fuel cost, pollution damage cost and the objective functions.     

基于数学规划法的蒸汽动力系统优化运行研究

为满足石油化工行业实际生产中各单元、各工艺过程对不同等级蒸汽的需求,将不同蒸汽动力循环过程归纳综合为一种通用的过程,并利用数学规划的方法建立了数学模型。采用数学规划法对实际操作系统进行优化,得到最佳操作参数,并与人工调度方案进行了比较。结果表明:对于复杂蒸汽动力系统的优化,借助优化模型和求解软件可以方便地确定系统最优运行状态,使整个蒸汽动力系统的运行费用最低。该方法可为过程动力、热能、工艺蒸汽等的分配提供参考数据,对实际蒸汽动力系统的优化改造有着重要的指导意义。     

火电厂超滤系统控制策略的改进与优化

火电机组水处理中超滤系统根据工艺周期进行常规反洗与加药反洗,传统的逻辑控制方案是根据DCS时序或功能块的执行顺序判断优先级顺序,从而导致系统逻辑执行异常.通过对超滤常规反洗与加药反洗控制优先级逻辑进行改进,同时,还对进水温度的控制加强优化;从而达到提升制水量,并且减少加药物品用量的目的.为超滤全自动方案提供可靠保障,有...     

Design and optimization of biomass power plant

Among the renewable energy sources, biomass offers some benefits due to its low cost and presumed zero-carbon emission when compared with fossil fuels. However, the moisture content of biomass is often high that lowers its heating value, reduces the combustion temperature and causes operational problems. Because of these, when burning biomass for power generation, biomass is often dried prior to the combustion. To lower the drying cost or to maximize the power output of a biomass power plant, proper heat integration in between the steam power plant and the drying process has to be considered. In this work, heat integration studies are performed to a biomass power plant that burns empty fruit bunches (EFB) as fuel. Composite curves of all studied cases are plotted to visualize the intensity and to identify opportunities of heat integration among the drying and power generation systems. A multi-stage drying process is proposed that employs steam and waste-heat from the power plant and the drying process, respectively. Results of this study show that with proper drying and heat integration, the overall efficiency of a biomass power plant can be significantly improved.     

动力电池双向热管理系统性能分析与优化

基于工质相变热虹吸效应,提出了动力电池双向热管理系统,通过改变工质充注量,60~220 g时,试验测试了该系统的双向热管理性能,并据此进行系统优化。结果表明：该热管理系统的正常运行有一个最低充注量。系统优化前,加热工况,系统换热功率受充注量的影响小;散热工况,系统的换热功率随充注量的增加而增大,随电池箱初始温度升高而增大,且强制散热效果要优于自然散热;相同充注量,换热板表面的最大温差随电池箱初始温度升高而增大,在3C放电倍率,无法控制电池表面温度低于45℃。系统优化后,圆管换热板系统的换热效果要优于矩形管换热板系统,且在3C放电倍率能将电池表面温度降低至43.4℃,换热板的温度一致性更好。     

基于带补偿随机规划的蒸汽动力系统优化设计

在蒸汽动力系统优化设计中,考虑不确定因素的优化策略能避免基于确定性设计策略的保守设计,并能针对不确定因素的实现提出相应的调度调节策略.本研究分析了蒸汽动力系统设计包含的不确定因素的特性及其对蒸汽动力系统优化目标和约束条件的影响.不确定因素的表达分成两类:基于时间变化表达和基于发生概率表达.对基于时间变化表达的因素,转化为多周期问题进行处理;对外部工艺过程变化引起的汽电需求不确定波动等基于发生概率表达的因素,应用随机规划策略,补偿不确定参数的实现可能引起的约束背离.基于本研究建立的多周期带补偿的二阶段随机规划MILP模型,求解蒸汽动力系统结构,同时优化调度调节策略,用调节决策和惩罚不足应对汽电需求等不确定因素的实现,实现系统安全稳定运行和经济效益最优.     

进气温度对燃气-蒸汽联合循环机组性能的影响

选取某200MW级燃气-蒸汽联合循环（GSCC）机组为研究对象,在环境温度与联合循环满负荷和部分负荷工况性能变化规律分析的基础上,本文提出了燃机进气温度控制技术。通过建模仿真和试验等方法研究了燃机进气温度变化对联合循环全工况性能的影响。结果表明,对于联合循环满负荷工况,通过进气冷却技术将燃机进气温度由32℃降低至12℃时,可增加联合循环功率14.2MW,同时提高热耗率2.3%;对联合循环80MW、120MW和160MW部分负荷工况,通过进气加热技术将燃机进气温度由12.5℃升高到40℃时,联合循环燃气耗量逐渐降低,联合循环效率分别提升0.86%、1.26%和1.11%。燃机进气温度控制技术建立了联合循环中底循环与顶循环间的耦合,在一定负荷和进气温度范围内调节燃机进气温度可有效改善联合循环性能,具有较高的研究和应用价值。     

基于碳捕集的燃煤机组热力系统优化及技术经济分析

碳捕集和封存是实现电力低碳化发展的关键所在,以600 MW机组为例,研究了碳捕集系统的能量流和质量流。提出了碳捕集系统与燃煤机组的耦合方式,计算了参考电站和碳捕集电站的热经济性。建立了碳捕集电站优化模型,以粒子群算法作为优化模型的求解算法,获得了系统的最优解。基于各设备投资成本,建立了碳捕集电站发电成本和CO2减排成本模型,研究了碳捕集电站的技术经济性。利用系统灵敏度分析方法,研究了碳税收和碳售价对发电成本和CO2减排成本的影响。结果表明：优化后碳捕集电站的热效率比优化前提高了1.1%;当CO2税收额高于0.33元/(kgCO2)时,碳捕集电站的经济性优于参考电站。