scholarly journals Hybrid Membrane Distillation and Wet Scrubber for Simultaneous Recovery of Heat and Water from Flue Gas

Entropy ◽  
2020 ◽  
Vol 22 (2) ◽  
pp. 178 ◽  
Author(s):  
Mohd Hizami Mohd Yusoff ◽  
Ein K. Nyunt ◽  
Muhammad Roil Bilad ◽  
Nasrul Arahman ◽  
Sri Mulyati ◽  
...  
Keyword(s):  
Water Vapor ◽  
Flow Rate ◽  
Flue Gas ◽  
Membrane Distillation ◽  
Heat Fluxes ◽  
Low Grade ◽  
Gas Temperature ◽  
Wet Scrubber ◽  
Low Grade Heat ◽  
Water Scrubber

Flue gas contains high amount of low-grade heat and water vapor that are attractive for recovery. This study assesses performance of a hybrid of water scrubber and membrane distillation (MD) to recover both heat and water from a simulated flue gas. The former help to condense the water vapor to form a hot liquid flow which later used as the feed for the MD unit. The system simultaneously recovers water and heat through the MD permeate. Results show that the system performance is dictated by the MD performance since most heat and water can be recovered by the scrubber unit. The scrubber achieved nearly complete water and heat recovery because the flue gas flows were supersaturated with steam condensed in the water scrubber unit. The recovered water and heat in the scrubber contains in the hot liquid used as the feed for the MD unit. The MD performance is affected by both the temperature and the flow rate of the flue gas. The MD fluxes increases at higher flue gas temperatures and higher flow rates because of higher enthalpy of the flue gas inputs. The maximum obtained water and heat fluxes of 12 kg m−2 h−1 and 2505 kJm−2 h−1 respectively, obtained at flue gas temperature of 99 °C and at flow rate of 5.56 L min−1. The MD flux was also found stable over the testing period at this optimum condition. Further study on assessing a more realistic flue gas composition is required to capture complexity of the process, particularly to address the impacts of particulates and acid gases.

scholarly journals Rolling membrane powered by low-temperature steam as a new approach to generate mechanical energy

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Chongshan Yin ◽  
Qicheng Liu ◽  
Qing Liu
Keyword(s):  
Water Vapor ◽  
Low Temperature ◽  
Combustion Engine ◽  
Mechanical Energy ◽  
Heat Energy ◽  
Steam Engine ◽  
Low Grade ◽  
Human Society ◽  
New Approach ◽  
Low Grade Heat

Abstract How to convert heat energy into other forms of usable energy more efficiently is always crucial for our human society. In traditional heat engines, such as the steam engine and the internal combustion engine, high-grade heat energy can be easily converted into mechanical energy, while a large amount of low-grade heat energy is usually wasted owing to its disadvantage in the temperature level. In this work, for the first time, the generation of mechanical energy from both high- and low-temperature steam is implemented by a hydrophilic polymer membrane. When exposed to water vapor with a temperature ranging from 50 to 100 °C, the membrane repeats rolling from one side to another. In nature, this continuously rolling of membrane is powered by the steam, like a miniaturized “steam engine”. The differential concentration of water vapor (steam) on the two sides of the membrane generates the asymmetric swelling, the curve, and the rolling of the membrane. In particular, results suggest that this membrane based “steam engine” can be powered by the steam with a relatively very low temperature of 50 °C, which indicates a new approach to make use of both the high- and low-temperature heat energy.

Low-Grade Heat Utilization Through Ultrasound-Enhanced Desorption of Activated Alumina/Water for Thermal Energy Storage

2020 ◽  
Author(s):  
Hooman Daghooghi Mobarakeh ◽  
Keshawa Bandara ◽  
Liping Wang ◽  
Robert Wang ◽  
Patrick E. Phelan ◽  
...  
Keyword(s):  
Water Vapor ◽  
Energy Storage ◽  
Thermal Energy ◽  
Input Power ◽  
Total Power ◽  
Low Grade ◽  
Ultrasonic Power ◽  
Activated Alumina ◽  
Heat Utilization ◽  
Low Grade Heat

Abstract Sorption thermal energy storage (TES) seems to be an auspicious solution to overcome the issues of intermittent energy sources and utilization of low-grade heat. Ultrasound-assisted adsorption/desorption of water vapor on activated alumina is proposed as a means of low-grade heat utilization through TES. The effects of ultrasonic power on the storing stage (desorption of water vapor) were analyzed to optimize the desorption and overall efficiencies. To determine and justify the effectiveness of incorporating ultrasound from an energy-savings point of view, an approach of constant total (heat plus ultrasound) input power of 25 W was adopted. To measure the extent of the effectiveness of using ultrasound, ultrasonic-power-to-total power ratios of 0.2 and 0.4 were investigated and the results compared with those of no-ultrasound (heat only) at the same total power. The regeneration temperature and desorption rate were measured simultaneously to investigate the effects of ultrasonication on regeneration temperature and utilization of low-grade heat. The experimental results showed that using ultrasound facilitates the regeneration of activated alumina at both power ratios without increasing the total input power. With regard to regeneration temperature, incorporating ultrasound decreases the regeneration temperature hence justifying the utilization of low-grade heat for thermal energy purposes. In terms of overall energy recovery of the adsorption thermal storage process, a new metric is proposed to justify incorporating ultrasound and any other auxiliary energy along with low-grade heat.

The Enlightenment of Updated Development of the USC Coal Fired Units

2017 ◽  
Author(s):  
Ji Wenhao ◽  
Li Daolin ◽  
Hu Xingsheng ◽  
Wan Peng
Keyword(s):  
Flue Gas ◽  
Technical Specification ◽  
Low Grade ◽  
Power Demand ◽  
Production Structure ◽  
Harmful Emission ◽  
The Enlightenment ◽  
Operation Results ◽  
Low Grade Heat ◽  
Further Development

An comparison of technical specification and updated operation results between two USC coal fired boilers namely RDK-8, Germany and WGQ-3, China has been considered under the global scenario related to the variation of industrial production structure, power demand cut down, more stringent carbon dioxide depression and larger quantity of renewable units engaged into the grid, in this respect a discussion and analysis have been carried out subjected to low grade heat recovering and harmful emission prevention from boiler flue gas and introduction carbon harmful emission prevention from boiler flue gas and their multiple benefits on energy saving and environmental protection, moreover the experience and gains in the field of flue gas heat recovering and mitigating pollution, including the proprietary technique (WGGH) by SPERI are briefly stated, thereby a conclusion of enlightenment for further development of these units is mentioned.

scholarly journals Heat Based Power Augmentation for Modular Pumped Hydro Storage in Smart Buildings Operation

2021 ◽  
Author(s):  
Yang Chen ◽  
Ahmad Abu-Heiba ◽  
Saiid Kassaee ◽  
Chenang Liu ◽  
Guodong Liu ◽  
...  
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Ground Level ◽  
Small Scale ◽  
Low Grade ◽  
Discharge Process ◽  
Gas Temperature ◽  
Oak Ridge ◽  
Storage Technology ◽  
Low Grade Heat

Abstract In the U.S., building sector is responsible for around 40% of total energy consumption and contributes about 40% of carbon emissions since 2012. Within the past several years, various optimization models and control strategies have been studied to improve buildings energy efficiency and reduce operational expenses under the constraints of satisfying occupants’ comfort requirements. However, the majority of these studies consider building electricity demand and thermal load being satisfied by unidirectional electricity flow from the power grid or on-site renewable energy generation to electrical and thermal home appliances. Opportunities for leveraging low grade heat for electricity have largely been overlooked due to impracticality at small scale. In 2016, a modular pumped hydro storage technology was invented in Oak Ridge National Laboratory, named Ground Level Integrated Diverse Energy Storage (GLIDES). In GLIDES, employing high efficiency hydraulic machinery instead of gas compressor/turbine, liquid is pumped to compress gas inside high-pressure vessel creating head on ground-level. This unique design eliminates the geographical limitation associated with existing state of the art energy storage technologies. It is easy to be scaled for building level, community level and grid level applications. Using this novel hydro-pneumatic storage technology, opportunities for leveraging low-grade heat in building can be economical. In this research, the potential of utilizing low-grade thermal energy to augment electricity generation of GLIDES is investigated. Since GLIDES relies on gas expansion in the discharge process and the gas temperature drops during this non-isothermal process, available thermal energy, e.g. from thermal storage, Combined Cooling, Heat and Power system (CCHP), can be utilized by GLIDES to counter the cooling effect of the expansion process and elevate the gas temperature and pressure and boost the roundtrip efficiency. Several groups of comparison experiments have been conducted and the experimental results show that a maximum 12.9% cost saving could be achieved with unlimited heat source for GLIDES, and a moderate 3.8% cost improvement can be expected when operated coordinately with CCHP and thermal energy storage in a smart building.

scholarly journals Exergy efficiency analysis of lignite-fired steam generator

2018 ◽  
Vol 22 (5) ◽  
pp. 2087-2101
Author(s):  
Drenusha Krasniqi-Alidema ◽  
Risto Filkoski ◽  
Marigona Krasniqi
Keyword(s):  
Steam Generator ◽  
Flue Gas ◽  
Power Plants ◽  
Thermal Power ◽  
Calorific Value ◽  
Feed Water ◽  
Low Grade ◽  
Gas Temperature ◽  
Steam Generators ◽  
Energy And Exergy

The operation of steam generators and thermal power plants is commonly evaluated on a basis of energy analysis. However, the real useful energy loss cannot be completely justified only by the First law of thermodynamics, since it does not differentiate between the quality and amount of energy. The present work aims to give a contribution towards identification of the sources and magnitude of thermodynamic inefficiencies in utility steam generators. The work deals with a parallel analysis of the energy and exergy balances of a coal-fired steam generator that belongs to a 315 MWe power generation unit. The steam generator is de-signed for operation on low grade coal - lignite with net calorific value 6280 to 9211 kJ/kg, in a cycle at 545?C/177.4 bar, with feed water temperature 251?C, combustion air preheated to 272?C and outlet flue gas temperature 160?C. Since the largest exergy dissipation in the thermal power plant cycle occurs in the steam generator, energy, and exergy balances of the furnace and heat exchanging surfaces are established in order to identify the main sources of inefficiency. On a basis of the analysis, optimization of the combustion and heat transfer processes can be achieved through a set of measures, including retrofitting option of lignite pre-drying with flue gas and air preheating with dryer exhaust gases.

Pressure-retarded membrane distillation for simultaneous hypersaline brine desalination and low-grade heat harvesting

2020 ◽  
Vol 597 ◽  
pp. 117765 ◽  
Author(s):  
Ziwen Yuan ◽  
Yanxi Yu ◽  
Li Wei ◽  
Xiao Sui ◽  
Qianhong She ◽  
...  
Keyword(s):  
Membrane Distillation ◽  
Low Grade ◽  
Low Grade Heat

Performance Evaluation of a Turbine Used in a Regenerative Organic Rankine Cycle

2012 ◽  
Author(s):  
Maoqing Li ◽  
Jiangfeng Wang ◽  
Lin Gao ◽  
Xiaoqiang Niu ◽  
Yiping Dai
Keyword(s):  
Flow Rate ◽  
Rotational Speed ◽  
Electrical Power ◽  
Organic Rankine Cycle ◽  
Axial Flow ◽  
Rankine Cycle ◽  
Operating Conditions ◽  
Working Fluid ◽  
Low Grade ◽  
Low Grade Heat

Due to environmental constraints, the Organic Rankine Cycle (ORC) is widely used to generate electricity from low grade heat sources. In ORC processes, the working fluid is an organic substance, which has a better thermodynamic performance than water for low grade heat recovery. The design of the turbine which is the key component in the ORC system strongly depends on the operating conditions and on the scale of the facility. This paper presents an experimental study on a prototype of an axial-flow turbine integrated into a regenerative ORC system with R123 as working fluid. The power output is 10kW scale, and the single-stage turbine is selected. The turbine is specially designed and manufactured, and a generator is connected to the turbine directly. In the experiment, the turbine is tested under different inlet pressure conditions (0.6–1.5MPa), different inlet temperature conditions (80–150°C) and different flow rate conditions. The experimental data such as the pressures, temperatures of the turbine inlet and outlet, flow rate, rotational speed, and electrical power generation are analyzed to find their inner relationships. During the test, the turbine rotational speed could reach more than 3010 r/min, while the design rotational speed is 3000 r/min. The isentropic efficiency of the turbine could reach 53%. The maximum electrical power generated by the turbine-generator is 6.57KW. From the test data the peak value of the temperature difference between the inlet and the outlet of the turbine is 53 °C, and the expansion ratio reaches about 11. The computational fluid dynamics (CFD) solvers is also used to analyze the performance of the turbine. The distributions of the pressure, Mach number, and static entropy in the turbine flow passage component are examined and the reasons are also obtained. This study reveals the relationships between the performance of the axial-flow turbine and its inlet and outlet vapor conditions. The experiment results and the CFD results lay a foundation for using this type turbine in the ORC systems which product electrical power from a few KW to MW.

Membrane distillation at the water-energy nexus: limits, opportunities, and challenges

2018 ◽  
Vol 11 (5) ◽  
pp. 1177-1196 ◽  
Author(s):  
Akshay Deshmukh ◽  
Chanhee Boo ◽  
Vasiliki Karanikola ◽  
Shihong Lin ◽  
Anthony P. Straub ◽  
...  
Keyword(s):  
Critical Review ◽  
High Salinity ◽  
Membrane Distillation ◽  
Low Grade ◽  
Water Energy Nexus ◽  
Low Grade Heat

This critical review investigates the potential for membrane distillation to desalinate high-salinity waters using low-grade heat at the water-energy nexus.

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