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.

Feasibility Study for Self-Sustained Wastewater Treatment Plants—Using Biogas CHP Fuel Cell, Micro-Turbine, PV and Wind Turbine Systems

This paper studies the application of renewable energy sources in wastewater treatment plants to achieve self-sustain- ability of power. The data of wastewater treatment plant in the rural city of Toukh-EGYPT are presented as a case-study. The primary objective is to provide an entirely renewable standalone power system, which satisfies lowest possible emissions with the minimum lifecycle cost. Mass balance principle is applied on the biodegradable components in the wastewater to evaluate the volume of digester gas that is produced from sludge through anaerobic digestion process. Using digester gas as a fuel lead to study combined-heat-and-power technologies, where fuel cell is selected in order to abide by the low emissions constraint. The study assessed the electrical power obtained from fuel cell and the utilization of the exhausted heat energy for additional electrical power production using a micro-turbine. After covering the major part of load demand, the use of other renewable energy sources was studied. The strength of both solar and wind energy was determined by the case-study location. Hybrid optimization model for electric renewable (HOMER) software was used to simulate the hybrid system composed of combined-heat-and-power units, wind turbines and photovoltaic systems. Simulation results gave the best system configuration and optimum size of each component beside the detailed electrical and cost analysis of the model.

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。

Low-carbon Operation of Combined Heat and Power Integrated Plants Based on Solar-assisted Carbon Capture

Accelerating the development of renewable energy and reducing CO_(2)emissions have become a general consensus and concerted action of all countries in the world. The electric power industry, especially thermal power industry, is the main source for fossil energy consumption and CO_(2)emissions. Since solvent-based post-combustion carbon capture technology would bring massive extra energy consumption, the application of solar-assisted carbon capture technology has attracted extensive attention. Due to the important role of coal-fired combined heat and power plants for serving residential and industrial heating districts, in this paper, the low-carbon operation benefits of combined heat and power integrated plants based on solar-assisted carbon capture(CHPIP-SACC) are fully evaluated in heat and power integrated energy system with a high proportion of wind power. Based on the selected integration scheme, a linear operation model of CHPIP-SACC is developed considering energy flow characteristics and thermal coupling interaction of its internal modules. From the perspective of system-level operation optimization, the day-ahead economic dispatch problem based on a mix-integer linear programming model is presented to evaluate the low-carbon benefits of CHPIP-SACC during annual operation simulation. The numerical simulations on a modified IEEE 39-bus system demonstrate the effectiveness of CHPIP-SACC for reducing CO_(2)emissions as well as increasing the downward flexibility. The impact of different solar field areas and unit prices of coal on the low-carbon operation benefits of CHPIP-SACC is studied in the section of sensitivity analysis.

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.

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 heat 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.

Performance Improvement of Combined Cycle Power Plant Based on the Optimization of the Bottom Cycle and Heat Recuperation

许多 F 班气体汽轮机联合了周期(GTCC ) 发电厂因为更少的排放和高效率，目前在中国被造。调查 GTCC 植物的效率改进兴趣大。一个联合周期与三压力再热热恢复蒸气生成器(HRSG ) 在这份报纸为学习被选择。以便最大化 GTCC 效率，操作参数的 HRSG 的优化被执行。操作参数借助于热力学的分析被决定，即 exergy 损失的最小化。蒸气 bottoming 周期效率上的 HRSG 入口气体温度的影响被讨论。当它是超过 590 掳 C 时，结果证明增加 HRSG 入口温度有更少的改进到蒸气周期效率。到在超过的周期的煤气的恢复的部分气体被学习。与气体的使用加入 HRSG 优化到煤气的热恢复，联合植物效率能在基础负担升起直到 59.05% 。另外， GTCC 发电厂的部分负担表演变得好一些。效率被 2.11% 在 50% 负担在 75% 负担并且在 4.17% 增加。

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。

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。

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。

火电厂源侧综合能源系统集成及性能评估研究

本文建立了以火电厂为核心,消纳可再生能源并提供冷热电汽综合能源服务的一套能源系统,通过对整体系统及关键子系统热力性能分析,验证了提出模型和方法的有效性。并研究了一些关键运行参数对系统综合性能的影响,验证了提出模型和方法的有效性和优越性。结果表明:通过改变火电厂的源侧参数,可以提高综合能源系统荷侧的输出量;且生物质转化气对汽轮机发电功率的影响最大。热泵系统的负荷随着进入系统中的给水流量的增大而增大,利用汽轮机中的部分抽汽来驱动热泵系统,虽然发电功率下降了10.88%,但是却为用户提供了16.8MW的热负荷和16.2MW的冷负荷以及27.78t/h的蒸汽量。

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。

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.

涉及长输供热管网的热电联产改造研究

文章以呼和浩特市托克托电厂为例,从电厂的供热潜力、长输供热管网的敷设方案等角度详细分析了涉及长输供热管网的热电联产改造。结果表明:托克托电厂能满足城市的远期供热负荷;传统供热方式与大温差供热方式相结合的综合供热方式更适合该项目;相比于DN1400管道,采用DN1600的输送管道,不仅能节约输送能耗,而且在供热年限内经济性更高;包裹110 mm厚的保温层后,整个管道热损失仅占3%。

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。

Optimization Potentials for the Waste Heat Recovery of a Gas-Steam Combined Cycle Power Plant Based on Absorption Heat Pump

A new waste heat recovery system is presented to recover exhausted steam waste heat from the steam turbine by absorption heat pump(AHP) in a gas-steam combined cycle(GSCC) power plant. The system can decrease energy consumption and further improve the energy utilization. The performance evaluation criteria are calculated, and exergy analysis for key components are implemented in terms of the energy and exergy analysis theory. Besides, the change of these criteria is also revealed before and after modification. The net power output approximately increases by 21738 kW, and equivalent coal consumption decreases by 5.58 g/kWh. A 1.81% and 1.92% increase in the thermal and exergy efficiency is respectively obtained in the new integrated system as the heating load is 401095 kJ at 100% condition. Meanwhile, the appropriate extraction parameters for heating have been also analyzed in the two systems. The proposed scheme can not only save energy consumption but also reduce emission and gain great economic benefit, which is proven to be a huge potential for practical application.

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.