scholarly journals Performance Analysis of a Waste-to-Energy System Integrated with the Steam–Water Cycle and Urea Hydrolysis Process of a Coal-Fired Power Unit

2022 ◽  
Vol 12 (2) ◽  
pp. 866
Author(s):  
Yuanyuan Zhang ◽  
Lai Wei ◽  
Xin Gao ◽  
Heng Chen ◽  
Qiubai Li ◽  
...  

An innovative hybrid energy system consisting of a waste-to-energy unit and a coal-fired power unit is designed to enhance the energy recovery of waste and decrease the investment costs of waste-to-energy unit. In this integrated design, partial cold reheat steam of the coal-fired unit is heated by the waste-to-energy boiler’s superheater. The heat required for partial preheated air of waste-to-energy unit and its feedwater are supplied by the feedwater of CFPU. In addition, an additional evaporator is deployed in the waste-to-energy boiler, of which the outlet stream is utilized to provide the heat source for the urea hydrolysis unit of coal-fired power plant. The stand-alone and proposed designs are analyzed and compared through thermodynamic and economic methods. Results indicate that the net total energy efficiency increases from 41.84% to 42.12%, and the net total exergy efficiency rises from 41.19% to 41.46% after system integration. Moreover, the energy efficiency and exergy efficiency of waste-to-energy system are enhanced by 10.48% and 9.92%, respectively. The dynamic payback period of new waste-to-energy system is cut down from 11.39 years to 5.48 years, and an additional net present value of $14.42 million is got than before.

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4345
Author(s):  
Peiyuan Pan ◽  
Meiyan Zhang ◽  
Gang Xu ◽  
Heng Chen ◽  
Xiaona Song ◽  
...  

A novel design has been developed to improve the waste-to-energy process through the integration with a biomass-fired power plant. In the proposed scheme, the superheated steam generated by the waste-to-energy boiler is fed into the low-pressure turbine of the biomass power section for power production. Besides, the feedwater from the biomass power section is utilized to warm the combustion air of the waste-to-energy boiler, and the feedwater of the waste-to-energy boiler is offered by the biomass power section. Based on a 35-MW biomass-fired power plant and a 500-t/d waste-to-energy plant, the integrated design was thermodynamically and economically assessed. The results indicate that the net power generated from waste can be enhanced by 0.66 MW due to the proposed solution, and the waste-to-electricity efficiency increases from 20.49% to 22.12%. Moreover, the net present value of the waste-to-energy section is raised by 5.02 million USD, and the dynamic payback period is cut down by 2.81 years. Energy and exergy analyses were conducted to reveal the inherent mechanism of performance enhancement. Besides, a sensitivity investigation was undertaken to examine the performance of the new design under various conditions. The insights gained from this study may be of assistance to the advancement of waste-to-energy technology.


Author(s):  
W. H. Jonathan Mak ◽  
Michel-Alexandre Cardin ◽  
Liu Ziqi ◽  
P. John Clarkson

The concept of resilience has emerged from various domains to address how systems, people and organizations can handle uncertainty. This paper presents a method to improve the resilience of an engineering system by maximizing the system economic lifecycle value, as measured by Net Present Value, under uncertainty. The method is applied to a Waste-to-Energy system based in Singapore and the impact of combining robust and flexible design strategies to improve resilience are discussed. Robust strategies involve optimizing the initial capacity of the system while Bayesian Networks are implemented to choose the flexible expansion strategy that should be deployed given the current observations of demand uncertainties. The Bayesian Network shows promise and should be considered further where decisions are more complex. Resilience is further assessed by varying the volatility of the stochastic demand in the simulation. Increasing volatility generally made the system perform worse since not all demand could be converted to revenue due to capacity constraints. Flexibility shows increased value compared to a fixed design. However, when the system is allowed to upgrade too often, the costs of implementation negates the revenue increase. The better design is to have a high initial capacity, such that there is less restriction on the demand with two or three expansions.


2021 ◽  
Vol 9 ◽  
Author(s):  
Huiling Su ◽  
Qifeng Huang ◽  
Zhongdong Wang

In the context of the energy crisis and environmental deterioration, the integrated energy system (IES) based on multi-energy complementarity and cascaded utilization of energy is considered as an effective way to solve these problems. Due to the different energy forms and the various characteristics in the IES, the coupling relationships among various energy forms are complicated which enlarges the difficulty of energy efficiency evaluation of the IES. In order to flexibly analyze the energy efficiency of the IES, an operation efficiency evaluation model for the IES is established. First, energy utilization efficiency (EUE) and exergy efficiency (EXE) are proposed based on the first/second law of thermodynamics. Second, the energy efficiency models for five processes and four subsystems of the IES are formed. Lastly, an actual commercial-industrial park with integrated energy is employed to validate the proposed method.


2019 ◽  
Vol 13 (1) ◽  
pp. 129-144 ◽  
Author(s):  
Carolina Koronen ◽  
Max Åhman ◽  
Lars J Nilsson

AbstractEnd-use efficiency, demand response and coupling of different energy vectors are important aspects of future renewable energy systems. Growth in the number of data centres is leading to an increase in electricity demand and the emergence of a new electricity-intensive industry. Studies on data centres and energy use have so far focused mainly on energy efficiency. This paper contributes with an assessment of the potential for energy system integration of data centres via demand response and waste heat utilization, and with a review of EU policies relevant to this. Waste heat utilization is mainly an option for data centres that are close to district heating systems. Flexible electricity demand can be achieved through temporal and spatial scheduling of data centre operations. This could provide more than 10 GW of demand response in the European electricity system in 2030. Most data centres also have auxiliary power systems employing batteries and stand-by diesel generators, which could potentially be used in power system balancing. These potentials have received little attention so far and have not yet been considered in policies concerning energy or data centres. Policies are needed to capture the potential societal benefits of energy system integration of data centres. In the EU, such policies are in their nascent phase and mainly focused on energy efficiency through the voluntary Code of Conduct and criteria under the EU Ecodesign Directive. Some research and development in the field of energy efficiency and integration is also supported through the EU Horizon 2020 programme. Our analysis shows that there is considerable potential for demand response and energy system integration. This motivates greater efforts in developing future policies, policy coordination, and changes in regulation, taxation and electricity market design.


Author(s):  
T. Simpkins ◽  
D. Cutler ◽  
K. Anderson ◽  
D. Olis ◽  
E. Elgqvist ◽  
...  

REopt is an energy planning platform offering concurrent, multiple technology integration and optimization capabilities to help clients meet their cost savings and energy performance goals. The REopt platform provides techno-economic decision support analysis throughout the energy planning process, from agency-level screening and macro planning to project development to energy asset operation. REopt employs an integrated approach to optimizing the energy costs of a site by considering electricity and thermal consumption, resource availability, complex tariff structures including time-of-use, demand and export rates, incentives, net metering, and interconnection limits. Formulated as a mixed integer linear program, REopt recommends an optimally sized mix of conventional and renewable energy, and energy storage technologies; estimates the net present value associated with implementing those technologies; and provides the cost-optimal dispatch strategy for operating them at maximum economic efficiency. The REopt platform can be customized to address a variety of energy optimization scenarios including policy, microgrid, and operational energy applications. This paper presents the REopt techno-economic model along with two examples of recently completed analysis projects.


2021 ◽  
Vol 9 ◽  
Author(s):  
Kai Zhang ◽  
Sebastian Troitzsch ◽  
Si-Yue Zhang ◽  
Erine Siew Pheng Teh ◽  
Lalitha Subramanian ◽  
...  

This article presents a case study of distributed generation and flexibility potential for a multienergy system in an urban district in Singapore. The analysis incorporates real-life data of a local energy system consisting of flexible loads (i.e., district cooling demand from air-conditioned buildings) and distributed generators (DGs) (i.e., waste-to-energy (W2E) generators and photovoltaic (PV) generators) from a representative study area. The demand-side flexibility (DSF) potentials from air-conditioned buildings are derived based on a state-space model and its underlying base load estimation. Besides the conventional consideration of PV system integration in the urban environment, we conducted a feasibility study of the distributed W2E technology deployment and estimated the generation potentials for the study area. Furthermore, to facilitate flexibility and energy exchange, market frameworks are proposed to harvest energy and flexibility from distributed energy resources (DERs) and in the real-time market context in Singapore.


2019 ◽  
pp. 3-17
Author(s):  
Turatbek Kasymov

This article reviews energy consumption in the Kyrgyz Republic economy, environmental indicators and strategies to further develop the national fuel and energy system to ensure energy efficiency and energy saving. An existing situation in energy efficiency of buildings in the country is described. Secondary legislation and by-laws approved by the Government of the Kyrgyz Republic as well as several technical standards, norms, methods and guidelines approved by the order of the State Construction Agency of the Kyrgyz Republic are presented. Applying modern insulating materials are suggested as possible solutions to increase energy efficiency and energy saving. The advantages of EPS-beton in comparison with other thermal insulation materials are discussed and foreign experience of use of EPS-beton products in increasing energy efficiency of buildings is presented.


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