A novel lignite pre-drying system with low-grade heat integration for modern lignite power plants

2014 ◽  
Vol 59 (33) ◽  
pp. 4426-4435 ◽  
Author(s):  
Cheng Xu ◽  
Gang Xu ◽  
Yu Han ◽  
Feifei Liang ◽  
Yaxiong Fang ◽  
...  
Keyword(s):  
Power Plants ◽  
Low Grade ◽  
Heat Integration ◽  
Drying System ◽  
Low Grade Heat

Low Temperature Heat Recovery Through Integration of Organic Rankine Cycle and CO2 Removal Systems in a NGCC

2014 ◽  
Author(s):  
Vittorio Tola ◽  
Matthias Finkenrath
Keyword(s):  
Low Temperature ◽  
Heat Recovery ◽  
Power Plants ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Low Grade ◽  
Co2 Removal ◽  
Temperature Heat ◽  
Temperature Levels ◽  
Low Grade Heat

Reducing carbon dioxide (CO2) emissions from power plants utilizing fossil fuels is expected to become substantially more important in the near- to medium-term due to increasing costs associated to national and international greenhouse gas regulations, such as the Kyoto protocol and the European Union Emission Trading Scheme. However, since net efficiency penalties caused by capturing CO2 emissions from power plants are significant, measures to reduce or recover efficiency losses are of substantial interest. For a state-of-the-art 400 MW natural gas-fueled combined cycle (NGCC) power plant, post-combustion CO2 removal based on chemical solvents like amines is expected to reduce the net plant efficiency in the order of 9–12 percentage points at 90% overall CO2 capture. A first step that has been proposed earlier to improve the capture efficiency and reduce capture equipment costs for NGCC is exhaust gas recirculation (EGR). An alternative or complementary approach to increase the overall plant efficiency could be the recovery of available low temperature heat from the solvent-based CO2 removal systems and related process equipment. Low temperature heat is available in substantial quantities in flue gas coolers that are required upstream of the CO2 capture unit, and that are used for exhaust gas recirculation, if applied. Typical temperature levels are in the order of 80°C or up to 100 °C on the hot end. Additional low-grade heat sources are the amine condenser which operates at around 100–130 °C and the amine reboiler water cooling that could reach temperatures of up to 130–140°C. The thermal energy of these various sources could be utilized in a variety of low-temperature heat recovery systems. This paper evaluates heat recovery by means of an Organic Rankine Cycle (ORC) that — in contrast to traditional steam Rankine cycles — is able to convert heat into electricity efficiently even at comparably low temperatures. By producing additional electrical power in the heat recovery system, the global performance of the power plant can be further improved. This study indicates a theoretical entitlement of up to additional 1–1.5 percentage points in efficiency that could be gained by integrating ORC technology with a post-combustion capture system for natural gas combined cycles. The analysis is based on fundamental thermodynamic analyses and does not include an engineering- or component-level design and feasibility analysis. Different ORC configurations have been considered for thermal energy recovery at varying temperature levels from the above-mentioned sources. The study focuses on simultaneous low-grade heat recovery in a single ORC loop. Heat recovery options that are discussed include in series, in parallel or cascaded arrangements of heat exchangers. Different organic operating fluids, including carbon dioxide, R245fa, and N-butane were considered for the analysis. The ORC performance was evaluated for the most promising organic working fluid by a parametric study. Optimum cycle operating temperatures and pressures were identified in order to evaluate the most efficient approach for low temperature heat recovery.

scholarly journals Low-grade waste heat driven desalination technology

2014 ◽  
Vol 5 ◽  
pp. A02 ◽  
Author(s):  
Alexander Christ ◽  
Xiaolin Wang ◽  
Klaus Regenauer-Lieb ◽  
Hui Tong Chua
Keyword(s):  
Carbon Dioxide ◽  
Power Plants ◽  
Waste Heat ◽  
Carbon Dioxide Emission ◽  
Expected Improvement ◽  
Low Grade ◽  
Low Emission ◽  
Process Plants ◽  
Desalination Technology ◽  
Low Grade Heat

Low-grade heat driven multi-effect distillation (MED) desalination is a very promising environmentally friendly, low emission technology. Many countries, such as Australia, are water short and conventional desalination technology is energy intensive. If a primary fossil fuel source is used, then desalination will significantly contribute to carbon dioxide emission. Low-grade waste heat from process plants and power plants generate minimal additional carbon dioxide. This source of energy is typically abundant at a temperature around 65–90 °C, which dovetails with MED technology. In this paper, we report on a new MED technology that couples perfectly with low grade waste heat to give at least a 25% freshwater yield improvement compared with conventional MED design. Typical applications and their expected improvement will also be reported.

scholarly journals The influence of adsorption chillers on CHP power plants

2018 ◽  
Vol 240 ◽  
pp. 05033 ◽  
Author(s):  
Karol Sztekler ◽  
Wojciech Kalawa ◽  
Sebastian Stefański ◽  
Jarosław Krzywanski ◽  
Karolina Grabowska ◽  
...  
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Industrial Process ◽  
Primary Energy ◽  
Simulation Software ◽  
Low Grade ◽  
Adsorption Chiller ◽  
Absorption Chillers ◽  
Low Grade Heat ◽  
Heat Power Plant

The simultaneous production of electricity, heat and cooling, the so-called trigeneration, allows for substantial savings in the chemical energy of fuels. More efficient use of the primary energy contained in fuels translates into tangible earnings for power plants while reductions in the amounts of fuel burned, and of non-renewable resources in particular, certainly have a favourable impact on the natural environment. The main aim of the above-described project was to analyse the influence of use adsorption contacted to conventional CHP power plant. An adsorption chiller is an item of industrial equipment that is driven by low grade heat and intended to produce chilled water and desalinated water. Adsorption chillers ACH can by used for utilization heat from many industrial process where temperature medium is too low for use absorption chillers. In this article modelled the cycle of a conventional heat power plant integrated with an adsorption chiller-based plant. Multi-variant simulation calculations were performed using IPSEpro simulation software.

scholarly journals A thermodynamic platform for evaluating the energy efficiency of combined power generation and desalination plants

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Kim Choon Ng ◽  
Muhammad Burhan ◽  
Qian Chen ◽  
Doskhan Ybyraiykul ◽  
Faheem Hassan Akhtar ◽  
...  
Keyword(s):  
Power Generation ◽  
Energy Efficiency ◽  
Power Plants ◽  
Flame Temperature ◽  
Primary Energy ◽  
Low Grade ◽  
Heat Engines ◽  
Desalination Plants ◽  
Low Grade Heat ◽  
Thermal Sources

AbstractIn seawater desalination, the energy efficiency of practical processes is expressed in kWh_electricity or low-grade-heat per m3 of water produced, omitting the embedded energy quality underlying their generation processes. To avoid thermodynamic misconceptions, it is important to recognize both quality and quantity of energy consumed. An unmerited quantitative apportionment can result in inferior deployment of desalination methods. This article clarifies misapprehensions regarding seeming parity between electricity and thermal sources that are sequentially cogenerated in power plants. These processes are represented by heat engines to yield the respective maximum (Carnot) work potentials. Equivalent work from these engines are normalized individually to give a corresponding standard primary energy (QSPE), defined via a common energy platform between the adiabatic flame temperature of fuel and the surroundings. Using the QSPE platform, the energy efficiency of 60 desalination plants of assorted types, available from literature, are compared retrospectively and with respect to Thermodynamic Limit.

scholarly journals Molecular design targets and optimization of low-temperature thermal desalination systems

2020 ◽  
Author(s):  
Alejandro Garciadiego ◽  
Tengfei Luo ◽  
Alexander Dowling
Keyword(s):  
Ionic Liquids ◽  
Molecular Design ◽  
Modern Society ◽  
Extraction Process ◽  
Molecular Engineering ◽  
Low Grade ◽  
Heat Integration ◽  
Modeling Framework ◽  
Thermal Desalination ◽  
Low Grade Heat

Access to clean, freshwater is an ever-growing concern for modern society as it is critical to ensure human health, protect threatened ecosystems, and promote economic growth and prosperity. While desalination is a promising pathway to meet global water demands, modern desalination processes remain energy-intensive. Directional solvent extraction (DSE) is an emerging membrane-free liquid-liquid extraction process to desalinate water using low-grade heat. Several unique features make DSE a potentially disruptive desalination technology: 1) it is thermally driven and utilizes low-grade heat; 2) it does not require the use of membranes; 3) there are opportunities to intensify, modularize and customize the process; 4) there is a vast solvent molecular engineering design space. Previous work includes success demonstration of a batch bench-scale DSE process, molecular simulations to understand solvent performance, and heat integration analysis of a single-stage pseudo-steady state DSE process. In this work, we propose a mathematical modeling framework for simultaneous technoeconomic optimization and heat integration of the DSE process. Using the framework, we perform rapid bottom-up screening to predict the performance of known organic acid and ionic liquid directional solvents in an optimized DSE process. We then use the optimization framework to identify continuous solvent property targets necessary to realize a levelized cost of water (LCOW) of less than \$0.50/m$^3$. Specifically, we find the thermoresponsive ability of the solvent and solubility of the solvent in water at a reference temperature are the most influential properties over the cost of the DSE process. Fatty acids are unable to achieve the LCOW goal due to the low thermoresponsive ability of the solvent. However, ionic liquids hold promise. Most importantly, we find a need to engineer ionic liquids with a lower solubility in saline reject.

scholarly journals Building and using temperature chart to determine thermodynamic efficiency of ship steam-compression heat transformers

2021 ◽  
Vol 2021 (3) ◽  
pp. 82-92
Author(s):  
Mikhail Mikhailovich Drozdov ◽  
Larisa Vasilievna Galimova ◽  
Andrey Yurievich Kuzmin
Keyword(s):  
Heat Source ◽  
Temperature Difference ◽  
Boiling Point ◽  
Power Plants ◽  
Thermodynamic Efficiency ◽  
Condensation Temperature ◽  
Low Grade ◽  
Regenerative Heat ◽  
Low Grade Heat

The article highlights the method of constructing a temperature chart, which allows evaluating the thermodynamic efficiency of ship combined thermal transformers. Refrigerants R134a, R717 were selected as the analyzed refrigerants in the construction of the temperature chart. The results of calculating the degree of thermodynamic perfection of single-stage combined thermal transformers without a regenerative heat exchanger are presented. The dependence of changing thermodynamic perfection on the melting and condensation temperature is given. The separation and classification of the areas of this dependence is proposed. The process of determining and constructing the characteristics that set the limit of application of the considered thermal transformers is described. The values influencing the position of the selected regions on the temperature chart are revealed. For the selected refrigerants there have been presented the dependences for correcting position of the areas depending on the amount of overheating, degree of supercooling and temperature difference between the boiling point and the temperature of low-potential heat source. The application of the temperature chart is analyzed under the following initial data: refrigerant R134a; condensation temperature 40°C; boiling point –20°C; ambient temperature 20°C; steam overheating 20 K; supercooling of the liquid 8 K; temperature difference between the low-grade heat source and the boiling point 8 K. The graph illustrates an example of using a temperature chart to determine the possibility of using combined heat transformers with specified parameters on the refrigerant R134a. Equations are derived for correcting the position of the lines of temperature charts for refrigerants permitted for the ship power plants.

scholarly journals Maximising the recovery of low grade heat: An integrated heat integration framework incorporating heat pump intervention for simple and complex factories

2015 ◽  
Vol 160 ◽  
pp. 172-184 ◽  
Author(s):  
J.H. Miah ◽  
A. Griffiths ◽  
R. McNeill ◽  
I. Poonaji ◽  
R. Martin ◽  
...  
Keyword(s):  
Heat Pump ◽  
Low Grade ◽  
Heat Integration ◽  
Integration Framework ◽  
Low Grade Heat

Efficient Co-Harvesting of Solar Energy and Low-Grade Heat by Molecular Photoswitches for High Energy Density, Long-Term Stable Solar Thermal Battery

2019 ◽  
Author(s):  
Zhao-Yang Zhang ◽  
Tao LI
Keyword(s):  
Energy Density ◽  
Solar Energy ◽  
High Performance ◽  
High Energy ◽  
Solar Thermal ◽  
High Energy Density ◽  
Low Grade ◽  
Thermal Battery ◽  
Low Grade Heat

Solar energy and ambient heat are two inexhaustible energy sources for addressing the global challenge of energy and sustainability. Solar thermal battery based on molecular switches that can store solar energy and release it as heat has recently attracted great interest, but its development is severely limited by both low energy density and short storage stability. On the other hand, the efficient recovery and upgrading of low-grade heat, especially that of the ambient heat, has been a great challenge. Here we report that solar energy and ambient heat can be simultaneously harvested and stored, which is enabled by room-temperature photochemical crystal-to-liquid transitions of small-molecule photoswitches. The two forms of energy are released together to produce high-temperature heat during the reverse photochemical phase change. This strategy, combined with molecular design, provides high energy density of 320-370 J/g and long-term storage stability (half-life of about 3 months). On this basis, we fabricate high-performance, flexible film devices of solar thermal battery, which can be readily recharged at room temperature with good cycling ability, show fast rate of heat release, and produce high-temperature heat that is >20<sup> o</sup>C higher than the ambient temperature. Our work opens up a new avenue to harvest ambient heat, and demonstrate a feasible strategy to develop high-performance solar thermal battery.

Sign in / Sign up

Export Citation Format

Share Document