Biomass Combined Heat and Power Generation for Anticosti Island: A Case Study

Combined heat and power (CHP) plants (co-generation plants) using biomass as fuel, can be an interesting alternative to the predominant electrical heating in Canada. The biomass-fueled boiler provides heat for the steam cycle which in turn generates electricity from the generator connected to the steam turbine. In addition, heat from the process is supplied to a district heating system. The heat can be extracted from the system in a number of ways, by using a back-pressure steam turbine, an extraction steam turbine or by extracting heat directly from the boiler. The objective of the paper is the design, modeling and simulation of such CHP plant. The plant should be sized for providing electric-ity and heat for the Anticosti Island community in Quebec.

Comparative Assessment of Combined-Heat-and-Power Performance of Small-Scale Aero-Derivative Gas Turbine Cycles

This paper considers comparative assessment of combined-heat-and-power (CHP) performance of three small-scale aero-derivative industrial gas turbine cycles in the petrochemical industry. The bulk of supposedly waste exhaust heat associated with gas turbine operation has necessitated the need for CHP application for greater fuel efficiency. This would render gas turbine cycles environ-mentally-friendly, and more economical. However, choosing a particular engine cycle option for small-scale CHP requires information about performances of CHP engine cycle options. The investigation encompasses comparative assessment of simple cycle (SC), recuperated (RC), and intercooled-recuperated (ICR) small-scale aero-derivative industrial gas turbines combined-heat-and-power (SS-ADIGT-CHP). Small-scale ADIGT engines of 1.567 MW derived from helicopter gas turbines are herein analysed in combined-heat-and-power (CHP) application. It was found that in this category of ADIGT engines, better CHP efficiency is exhibited by RC and ICR cycles than SC engine. The CHP efficiencies of RC, ICR, and SC small-scale ADIGT-CHP cycles were found to be 71%, 60%, and 56% respectively. Also, RC engine produces the highest heat recovery steam generator (HRSG) duty. The HRSG duties were found to be 3171.3 kW for RC, 2621.6 kW for ICR, and 3063.1 kW for SC. These outcomes would actually meet the objective of aiding informed preliminary choice of small-scale ADIGT engine cycle options for CHP application.

Technical and Economic Aspects and Experience from 6 Years of Operating the Technology Using the Waste Heat from the Exhaust Gases of Heat Sources and 3 Years of Operating a Heating Plant in an Autonomous, Island Regime

This article is focused on technical and economic evaluation of more than 6-years experiences of operating the Waste Heat Recovery technology—the manner and system of flue gas processing generated in the combustion process in heat & power plants, cogeneration units, etc., which burn the gaseous fuel, primarily natural gas, or methane, biogas, geothermal gas, or other gaseous mixtures containing hydrogen. The solution proposes a more effective and non-traditional use of gaseous fuel for heating, the flue gases of which are processed in order to extract additional utilisable heat, with potential elimination of CO2 from them. Deploying of the heating plant in an island regime (OFF-GRID) enables definition of the benefits brought by the 3 years of operational experience and presents visions for the future offering the possibility to utilise the support energy services at the municipal as well as regional level.

计及氢能高效利用和热电灵活输出的综合能源系统源荷灵活运行策略

为进一步发挥氢能高效利用优势,构建绿色低碳能源系统,提出一种计及氢能高效利用和热电联产灵活输出的综合能源系统源荷灵活运行策略。首先,对源侧供能模型进行两方面改进:一是引入含风电制氢、燃气混氢、多能用氢和储氢的氢能利用模型,并考虑到电解水和甲烷化反应过程中的热量散失情况,引入热量回收装置,构建计及热量回收的氢能高效利用模型;二是针对常规热电联产灵活性不足的问题,构建含电锅炉和有机朗肯循环的热电灵活输出模型,以解耦常规热电联产“以热定电”和“以电定热”限制。其次,在荷侧引入含可转移、可削减和可平移的电、热柔性负荷,以缓解电、热负荷峰谷差,并与源侧相结合,形成源荷灵活运行模型。最后,综合考虑阶梯型碳交易成本、设备运行维护成本、弃风成本以及购能成本,建立综合能源系统源荷灵活优化运行模型。采用CPLEX求解器对所提综合能源系统源荷灵活运行模型进行求解,并设置不同场景进行对比。结果表明,相比常规氢能利用模型,考虑所提计及热量回收的氢能高效利用模型时,系统的总成本、碳排放量分别降低了1.92%、4.22%,并且引入热电联产改进模型后,其总成本、碳排放量可进一步降低4.08%、7.32%,实现系统低碳、经济和灵活运行。

基于斜温层等效容积的大型蓄热罐动态特性分析

斜温层蓄热罐可以提高热电联产(combined heat and power,CHP)机组在供热期间的调峰能力,因此逐渐向大型化发展,但设计参数对蓄热罐的性能影响较大,且采用目前的性能评估方法效率较低。为此,建立大型蓄热罐的物理模型及数学模型,研究蓄热过程中斜温层的形成及变化过程,提出斜温层等效容积的概念,同时分析结构参数及运行参数对斜温层等效容积的影响。结果表明:形成稳定斜温层后,随着蓄热量的增加,斜温层厚度变化不大,采用斜温层等效容积可以更高效的评估蓄热罐的性能。比较不同工况下蓄热罐等效容积的相对变化量可知,不同影响因素对斜温层等效容积的影响从高到低排序依次为布水器布置、蓄热流量、高径比和冷热水温差。研究成果为大型蓄热罐的性能评估提供了一种新参考。

1 kW家庭PEMFC-CHP系统热量分析

为考核微型燃料电池热-电联供系统的热量利用程度,采集了一年中日本某家庭使用的1 k W质子交换膜燃料电池(PEMFC)的微型热-电联产系统各单元的数据,进行统计与分析,从热量利用的角度,计算各单元热量输入输出效率。结果表明,储热水箱散热与输运管道散热是系统热损失较多的薄弱环节。相关统计与分析,对改进类似热-电联产系统,进一步提高能源综合利用效率具有参考意义。

多市场参与下热电联产虚拟电厂低碳经济协同调度方法

热电联产(combined heat and power,CHP)机组与虚拟电厂(virtual power plant,VPP)结合,可以有效提高能源利用效率,增强电力系统运行的可靠性及稳定性。为保证CHP-VPP灵活、低碳、经济运行,文中提出一种聚合风电、光伏、CHP机组、锅炉、碳捕集设备、燃气轮机、燃料电池、储能及电、热负荷的综合能源VPP,并在参与电-热-旋转备用-碳等多市场下,研究其低碳经济协同调度问题。首先,以各时刻VPP在多市场下整体净收益最大为目标,建立其CHP-VPP两阶段鲁棒优化调度模型;然后,考虑新能源出力、市场价格及负荷的不确定性,利用蒙特卡洛法进行场景削减,从而降低系统风险,增强其鲁棒性;最后,采用列与约束生成算法对模型进行求解,得到最恶劣场景下系统运行的经济性最优调度方案。仿真结果表明:所提综合能源VPP结构合理,可通过动态调整碳捕集设备及储能电池,达到平抑新能源出力波动的效果,从而实现碳排放的大幅降低;所提调度策略可有效保证源-荷-储多侧电、热资源的协同优化运行,提高VPP的灵活性、经济性和低碳性。

考虑压降的开式布雷顿CHP装置性能优化

考虑工质在流动过程中的压降不可逆性,建立开式简单布雷顿热电联产装置的有限时间热力学模型。以可用能率、火用输出率、利润率、第一定律效率和火用效率为目标研究装置的性能。通过Matlab数值计算,在无燃料消耗和装置尺寸约束下,优化了压气机进口相对压降,得到了最优可用能率、火用输出率和利润率,进一步优化压比,得到了最大火用输出率和利润率;在有约束条件下,优化压气机进口相对压降,得到了最优第一定律效率和火用效率,同时得到了各部件最佳的流通面积分配,进一步优化压比,得到了最大第一定律效率和火用效率。研究设计参数对装置最优性能的影响,发现分别存在最佳的供热温度使火用输出率、利润率和火用效率取得双重最大值。通过比较发现按最大火用输出率设计能使装置具有较大的可用能率和较低的压比,按最大利润率设计能使装置具有较大的第一定律效率和火用效率以及较低的燃料和空气消耗。

含电动汽车和热电联产的区域微电网参与电网辅助服务调度

如今,在发达的特大城市,越来越多的分布式电源和电动汽车接入微电网。该文提出一个区域微电网,由一个热电联供系统和一系列插电式电动汽车组成。其主要目的是通过将PEV整合为快速响应存储来提供辅助服务和充分利用可再生能源提高系统的能源利用率和经济效益。停车场会聚集形成电力电子设备集群,并与CHP签订双边合同,以便能够参与调节电力市场。提出改进的乌鸦算法,对问题进行求解。通过MATLAB对算法进行数值仿真表明,如果区域微电网参与电力市场调控,每兆瓦的经济价值显著提高,总利润增加。

煤电“三改联动”技术综述及讨论

“三改联动”是促进煤电清洁低碳发展的重要技术路线。节能降碳改造主要以300/600 MW等级亚临界及超临界、高煤耗的老旧机组为主,采用升参数综合改造方案可以有效降低供电煤耗,同时提高机组灵活性。下一步“降碳”方向是锅炉的生物质掺烧。煤电机组是当前及未来一段时间适合我国国情的主要灵活性资源。煤电机组灵活性改造要解决锅炉低负荷稳燃、水冷壁水动力安全及受热面局部超温、SCR入口烟温低等问题,汽轮机的高温承压部件热应力问题,热控系统的自动调节回路在深调负荷下投运正常问题。分析认为,通过大规模热储能装置协同煤电机组调峰,是未来一个重要发展方向。本文从供汽能力、经济性、可靠性方面,深入研究了煤电机组以主蒸汽、冷再、热再作为主要汽源的工业供汽方案,认为基于中联门参调的热再抽汽方案是宽负荷条件下工业供汽改造的优选技术方案。为了进一步提高热电联产机组供热能力,低压缸微出力方案投资少、节能效果好、运行灵活,是优先选择的方案。“三改联动”深入推进,需要能源体制革命的推动和支撑,要完善适应新型电力系统配套的电力市场体系,充分体现市场化运作机制,提高煤电企业改造的积极性、主动性。

Dynamic scheduling of market price-based combined heat–power-constrained renewable microgrid

In this paper,a market price-based combined heat–power dynamic dispatch model for a microgrid is presented.The microgrid comprises cogeneration units and wind and solar power-generation units.A battery and a heat storage tank are incorporated to optimally balance variations in heat-and-power load demands.The proposed model explores the impact of market prices of electricity,heat supply and load variability on the optimal schedule such that profit maximizes and emission,loss and waste heat are minimized.The Weibull probability distribution function is applied to characterize the uncertain renewable power variable in the model and to find the over-and under-scheduling costs.The problem is solved using an improved differential evolution algorithm in which a fuzzy membership module is appended to obtain a solution having the highest attainment for the selected multiple objectives.The results show that the proposed model can handle uncertain heat–power demand and price scenarios to produce feasible and optimal schedules with owner profits,heat utilization and renewable share varying between 10.55–115.97%,72.51–90.39%and 26.82–38.05%,respectively.

主动式热平衡NG-CHP与GSHP耦合分布式系统集成研究

针对浅层地热能应用过程中尚未解决的热平衡控制、天然气基分布式能源系统含硫低温烟气余热无法回收利用两个关键问题,基于能的综合梯级利用以及主动式热平衡思想,提出基于主动式热平衡集成机理的燃气轮机与热泵耦合一体化应用分布式热电联产系统,借助新型集成方式将含硫低温烟气余热回收与土壤源热泵一体化应用,不仅同时解决含硫低温烟气余热回收以及热失衡问题,并大幅提高系统热力性能与系统运行稳定性。采用流程模拟软件Aspen-plus完成新型系统以及参比系统性能对比计算,计算结果表明,较之参比系统,该新型系统总能系统效率达到82.7%,较参比系统73.8%,提高8.9个百分点;?效率为28.8%,较参比系统25.8%,提高3个百分点。该新型统的集成方法与思路为中低温烟气余热的高效应用提供一种新解决途径。

Distributed energy management for interconnected operation of combined heat and power-based microgrids with demand response

From the perspective of transactive energy, the energy trading among interconnected microgrids(MGs) is promising to improve the economy and reliability of system operations. In this paper, a distributed energy management method for interconnected operations of combined heat and power(CHP)-based MGs with demand response(DR) is proposed. First, the system model of operational cost including CHP, DR, renewable distributed sources, and diesel generation is introduced, where the DR is modeled as a virtual generation unit. Second, the optimal scheduling model is decentralized as several distributed scheduling models in accordance with the number of associated MGs. Moreover, a distributed iterative algorithm based on subgradient with dynamic search direction is proposed. During the iterative process, the information exchange between neighboring MGs is limited to Lagrange multipliers and expected purchasing energy. Finally,numerical results are given for an interconnected MGs system consisting of three MGs, and the effectiveness of the proposed method is verified.

Combined heat and power economic dispatch problem using firefly algorithm

Cogeneration units, which produce both heat and electric power, are found in many process industries. These industries also consume heat directly in addition to electricity. The cogeneration units operate only within a feasible zone. Each point within the feasible zone consists of a specific value of heat and electric power. These units are used along with other units, which produce either heat or power exclusively. Hence, the economic dispatch problem for these plants to optimize the fuel cost is quite complex and several classical and meta-heuristic algo- rithms have been proposed earlier. This paper applies the firefly algorithm, which is inspired by the behavior of fireflies which attract each other based on their luminosity. The results obtained have been compared with those obtained by other methods earlier and showed a marked improvement over the earlier methods.

Combined heat and power economic dispatch problem using the invasive weed optimization algorithm

Cogeneration units which produce both heat and electric power are found in many process industries. These industries also consume heat directly in addition to electricity. The cogeneration units operate only within a feasible zone. Each point within the feasible zone consists of a specific value of heat and electric power. These units are used along with other units which produce either heat or power exclusively. Hence the economic dispatch problem for these plants optimizing the fuel cost is quite complex and several classical and meta-heuristic algo- rithms have been proposed earlier. This paper applies the invasive weed optimization algorithm which is inspired by the ecological process of weed colonization and distribu- tion. The results obtained have been compared with those obtained by other methods earlier and showed a marked improvement over earlier ones.

Carbon emission impact on the operation of virtual power plant with combined heat and power system

A virtual power plant （VPP） can realize the aggregation of distributed generation in a certain region, and represent distributed generation to participate in the power market of the main grid. With the expansion of VPPs and ever-growing heat demand of consumers, managing the effect of fluctuations in the amount of available renewable resources on the operation of VPPs and maintaining an economical supply of electric power and heat energy to users have been important issues. This paper proposes the allocation of an electric boiler to realize wind power directly converted for supplying heat, which can not only overcome the limitation of beat output from a combined heat and power （CHP） unit, but also reduce carbon emissions from a VPP. After the electric boiler is considered in the VPP operation model of the combined heat and power system, a multi-objective model is built, which includes the costs of carbon emissions, total operation of the VPP and the electricity traded between the VPP and the main grid. The model is solved by the CPLEX package using the fuzzy membership function in Matlab, and a case study is presented. The power output of each unit in the case study is analyzed under four scenarios. The results show that after carbon emission is taken into account, the output of low carbon units is significantly increased, and the allocation of an electric boiler can facilitate the maximum absorption of renewable energy, which also reduces carbon emissions from the VPP.

Distributed Real-time State Estimation for Combined Heat and Power Systems

This paper proposes a distributed real-time state estimation(RTSE)method for the combined heat and power systems(CHPSs).First,a difference-based model for the heat system is established considering the dynamics of heat systems.This heat system model is further used along with the power system steady-state model for holistic CHPS state estimation.A cubature Kalman filter(CKF)-based RTSE is developed to deal with the system nonlinearity while integrating both the historical and present measurement information.Finally,a multi-timescale asynchronous distributed computation scheme is designed to enhance the scalability of the proposed method for largescale systems.This distributed implementation requires only a small amount of information exchange and thus protects the privacy of different energy systems.Simulations carried out on two CHPSs show that the proposed method can significantly improve the estimation efficiency of CHPS without loss of accuracy compared with other existing models and methods.

Integrated Heat and Power Dispatch Model for Wind-CHP System with Solid Heat Storage Device Based on Robust Stochastic Theory

This paper built a combined heat and power（CHP） dispatch model for wind-CHP system with solid heat storage device（SHS） aiming at minimizing system coal consumption, and set system demand-supply balance and units＇ operation conditions as the operation constraints. Furthermore, robust stochastic optimization theory was used to describe wind power output uncertainty. The simulation result showed that SHS increased CHP peak-valley shifting capability and reduced abandoned wind rate from 12% to 6%, and reduced 5% coal consumption, compared with the original system operation by flexible charging electric power and heating. The payback period of employing SHS in wind-CHP system is far shorter than SHS expected service life.

Dispatch Model for Integrated Heat and Power Systems Considering Internal Composition of CHP Plants

An integrated heat and power system(IHPS)is a promising approach for alleviating wind curtailment problems.In an IHPS,the combined heat and power(CHP)plant is the key component,which supplies both heat and electric loads,and couples the thermal system and power system.However,existing research commonly ignores or simplifies the internal composition of CHP plants,which could lead to some unavoidable errors.This paper focuses on the internal composition of CHP plants,and models the physical processes in different components and flexible resources in the CHP plant.Furthermore,a joint dispatch problem of an IHPS with the above CHP plant models is formulated,and an iterative algorithm is developed to handle the nonlinearity in this problem.Case studies are performed based on a real CHP plant in Northern China,and the results indicate that the synergistic effect of different energy resources in the CHP plant is realized by the joint dispatch model,which promotes wind power accommodation and reduces fossil fuel consumption.

Optimal Combined Heat and Power Economic Dispatch Using Stochastic Fractal Search Algorithm

Combined heat and power(CHP)generation is a valuable scheme for concurrent generation of electrical and thermal energies.The interdependency of power and heat productions in CHP units introduces complications and non-convexities in their modeling and optimization.This paper uses the stochastic fractal search(SFS)optimization technique to treat the highly non-linear CHP economic dispatch(CHPED)problem,where the objective is to minimize the total operation cost of both power and heat from generation units while fulfilling several operation interdependent limits and constraints.The CHPED problem has bounded feasible operation regions and many local minima.The SFS,which is a recent metaheuristic global optimization solver,outranks many current reputable solvers.Handling constraints of the CHPED is achieved by employing external penalty parameters,which penalize infeasible solution during the iterative process.To confirm the strength of this algorithm,it has been tested on two different test systems that are regularly used.The obtained outcomes are compared with former outcomes achieved by many different methods reported in literature of CHPED.The results of this work affirm that the SFS algorithm can achieve improved near-global solution and compare favorably with other commonly used global optimization techniques in terms of the quality of solution,handling of constraints and computation time.