scholarly journals Influence of heat recuperation in ORC power plant on efficiency of waste heat utilization

2010 ◽  
Vol 31 (4) ◽  
pp. 111-123 ◽  
Author(s):  
Aleksandra Borsukiewicz-Gozdur
Keyword(s):  
Power Plant ◽  
Output Power ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Internal Heat ◽  
External Heat ◽  
Working Fluid ◽  
Heat Utilization ◽  
Heat Recuperation ◽  
Waste Heat Utilization

Influence of heat recuperation in ORC power plant on efficiency of waste heat utilization The present work is devoted to the problem of utilization of the waste heat contained in the exhaust gases having the temperature of 350 °C. Conversion of the waste heat into electricity using a power plant working with organic fluid cycles is considered. Three Organic Rankine Cycle (ORC) power plant solutions are analysed and compared: a solution with the basic, single thermodynamic conversion cycle, one with internal heat recuperation and one with external heat recuperation. It results from the analysis that it is the proper choice of the working fluid evaporation temperature that fundamentally affects the maximum of the ORC plant output power. Application of the internal heat recuperation in the plant basic cycle results in the output power increase of approx. 5%. Addition of the external heat recuperation to the plant basic cycle, in the form of a secondary supercritical ORC power cycle can rise the output power by approx. 2%.

Working Fluid Selection for a Waste Heat Recovery Organic Rankine Cycle (ORC) Applied to a Petroleum Distillation Process

2019 ◽  
Author(s):  
Sergio Peralta ◽  
Cesar Celis
Keyword(s):  
Power Plant ◽  
Physical Properties ◽  
Power Plants ◽  
Waste Heat ◽  
Selection Process ◽  
Organic Rankine Cycle ◽  
Internal Heat ◽  
Working Fluid ◽  
Working Fluids ◽  
Working Fluid Selection

Abstract This work describes a working fluid selection process for an ORC based power plant that uses as heat source waste heat from a petroleum distillation furnace. Sixteen (16) organic fluids previously considered for similar applications are analyzed based on environmental, safety and physical properties. Two different power plants layouts, a basic one and another featuring an internal heat exchanger (IHE), are analyzed. The combinations between working fluids and plant layouts seek to maximize the ORC-based power plant thermal efficiency. ORC exergy destruction and exergy efficiency are also accounted for. In this work, the close interrelation between working fluids thermo-physical properties and expander dimensionless characteristics is also assessed. The main results indicate that R245ca and R245fa are the working fluid leading to both the highest thermal (∼16%) and exergy efficiencies (∼23%), and the lowest exergy destructions (∼703 kW). Based on required properties of the selected working fluid, an axial turbine design seems to be the most appropriate ORC expander technology for the particular application discussed in this paper. The outcomes from this work will be used as the basis for the detailed design of the components of an ORC-based power plant focused on increasing the overall efficiency of petroleum distillation processes.

PBMR Desalination Options: An Economic Study

2008 ◽  
Author(s):  
Riaan de Bruyn ◽  
Ryan Hannink ◽  
Reiner Kuhr ◽  
Jan P. Van Ravenswaay ◽  
Nick Zervos ◽  
...  
Keyword(s):  
Power Plant ◽  
Low Temperature ◽  
Power Output ◽  
Waste Heat ◽  
Back Pressure ◽  
Working Fluid ◽  
Brayton Cycle ◽  
Heat Utilization ◽  
Waste Heat Utilization ◽  
Pressure Compressor

The Pebble Bed Modular Reactor (PBMR), under development in South Africa, is an advanced helium-cooled graphite moderated high-temperature gas-cooled nuclear reactor. The heat output of the PBMR is primarily suited for process applications or power generation. In addition, various desalination technologies can be coupled to the PBMR to further improve the overall efficiency and economics, where suitable site opportunities exist. Several desalination application concepts were evaluated for both a cogeneration configuration as well as a waste heat utilization configuration. These options were evaluated to compare the relative economics of the different concepts and to determine the feasibility of each configuration. The cogeneration desalination configuration included multiple PBMR units producing steam for a power cycle, using a back-pressure steam turbine generator exhausting into different thermal desalination technologies. These technologies include Multi-Effect Distillation (MED), Multi-Effect Distillation with Thermal Vapor Compression (MED-TVC) as well as Multi-Stage Flash (MSF) with all making use of extraction steam from backpressure turbines. These configurations are optimized to maximize gross revenue from combined power and desalinated water sales using representative economic assumptions with a sensitivity analysis to observe the impact of varying power and water costs. Increasing turbine back pressure results in a loss of power output but a gain in water production. The desalination systems are compared as incremental investments. A standard MED process with minimal effects appears most attractive, although results are very sensitive with regards to projected power and water values. The waste heat utilization desalination configuration is based on the current 165 MWe PBMR Demonstration Power Plant (DPP) to be built for the South African utility Eskom. This demonstration plant is proposed at the Koeberg Nuclear site and utilizes a direct, single shaft recuperative Brayton Cycle with helium as working fluid. The Brayton Cycle uses a pre-cooler and inter-cooler to cool the helium before entering the low-pressure compressor (LPC) and the high-pressure compressor (HPC) respectively. The pre-cooler and intercooler rejects 218 MWt of waste heat at 73°C and 63°C, respectively. This waste heat is ideally suited for some low temperature desalination processes and can be used without negative impact on the power output and efficiency of the nuclear power plant. These low temperature processes include Low Temperature Multi-Effect Distillation (LT-MED) as well Reverse Osmosis (RO) with pre-heated water. The relative economics of these design concepts are compared as add-ons to the PBMR-DPP and the results include a net present value (NPV) study for both technologies. From this study it can be concluded that both RO as well LT-MED provide water at reasonable production rates, although a final study recommendation would be based on site and area specific requirements.

scholarly journals Beneficial Reuse of Industrial CO2 Emissions Using a Microalgae Photobioreactor: Waste Heat Utilization Assessment

Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2634 ◽  
Author(s):  
Daniel T. Mohler ◽  
Michael H. Wilson ◽  
Zhen Fan ◽  
John G. Groppo ◽  
Mark Crocker
Keyword(s):  
Heat Transfer ◽  
Power Plant ◽  
Biomass Production ◽  
Waste Heat ◽  
Point Sources ◽  
Production Costs ◽  
Transfer Coefficients ◽  
Wind Speeds ◽  
Heat Utilization ◽  
Waste Heat Utilization

Microalgae are a potential means of recycling CO2 from industrial point sources. With this in mind, a novel photobioreactor (PBR) was designed and deployed at a coal-fired power plant. To ascertain the feasibility of using waste heat from the power plant to heat algae cultures during cold periods, two heat transfer models were constructed to quantify PBR cooling times. The first, which was based on tabulated data, material properties and the physical orientation of the PBR tubes, yielded a range of heat transfer coefficients of 19–64 W m−2 K−1 for the PBR at wind speeds of 1–10 m s−1. The second model was based on data collected from the PBR and gave an overall heat transfer coefficient of 24.8 W m−2 K−1. Energy penalties associated with waste heat utilization were found to incur an 18%–103% increase in energy consumption, resulting in a 22%–70% reduction in CO2 capture for the scenarios considered. A techno-economic analysis showed that the cost of heat integration equipment increased capital expenditures (CAPEX) by a factor of nine and increased biomass production costs by a factor of three. Although the scenario is thermodynamically feasible, the increase in CAPEX incurs an increase in biomass production cost that is economically untenable.

Integrated Steam/Organic Rankine Cycle (ISORC) for Waste Heat Recovery in Distributed Generation and Combined Heat and Power Production

2010 ◽  
Author(s):  
Yaroslav Chudnovsky ◽  
Mikhail Gotovsky ◽  
Valentin Arefiev ◽  
Mark Greenman ◽  
Victor Fomin ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Distributed Generation ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Industrial Applications ◽  
Heat Utilization ◽  
Energy Efficiency Improvement ◽  
Waste Heat Utilization ◽  
Cycle Efficiency

Energy efficiency improvement and waste heat utilization in power generation and energy intensive industrial applications are in the main focus of the researchers and engineers nowadays. A great deal of experience was gained by the industrial leaders such as ORMAT, Siemens, Caterpillar, Turboden, and others. However, the commercially and semi-commercially available systems for waste heat utilization have certain restrictions that limit the utilization cycle efficiency to approximately 18%. The paper presents an innovative concept of waste heat utilization system that allows reaching the utilization cycle efficiency up to 28–30% employing low-boiling media such as butane, propane, pentane and others. Applying such a concept to Distributed Generation systems the overall energy efficiency could be boost up to 58–60% and further up to 90% in case of CHP production.

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