Renewable Energy Based Dimethyl-Ether Production System Linked With Industrial Waste Heat

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Magd N. DinAli ◽  
Ibrahim Dincer
Keyword(s):  
Renewable Energy ◽  
Dimethyl Ether ◽  
Production System ◽  
Waste Heat ◽  
Synthesis Method ◽  
Simulation Software ◽  
Proton Exchange ◽  
Integrated System ◽  
Synthesis System ◽  
Energy And Exergy

A new renewable energy based dimethyl-ether (DME) production system is proposed in this paper. The DME is then produced through the indirect synthesis method where methanol is produced first through carbon hydrogenation process, then methanol derived to a process called methanol dehydration to produce the DME. The proposed integrated system consists of four main subsystems named as carbon capturing and heat recovery system, proton exchange membrane (PEM) hydrogen production system, methanol synthesis system, and the DME synthesis system. The main inputs are electrical energy from photovoltaic (PV) solar panels and thermal energy from flue gas waste heat. The system is modeled and simulated using both aspen plus process simulation software and engineering equation solver (EES) and assessed based on energy and exergy approaches. The energy and exergy efficiencies are determined to be 40.46% and 52.81%, respectively.

Optimum Design and Performance Simulation of a Multi-device Integrated System Based on a Proton Exchange Membrane Fuel Cell

2022 ◽  
pp. 1-33
Author(s):  
Xiuqin Zhang ◽  
Wentao Cheng ◽  
Qiubao Lin ◽  
Longquan Wu ◽  
Junyi Wang ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Power Density ◽  
Power Output ◽  
Proton Exchange Membrane ◽  
Waste Heat ◽  
Proton Exchange ◽  
Integrated System ◽  
Interior Space ◽  
And Performance ◽  
Exchange Membrane

Abstract Proton exchange membrane fuel cells (PEMFCs) based on syngas are a promising technology for electric vehicle applications. To increase the fuel conversion efficiency, the low-temperature waste heat from the PEMFC is absorbed by a refrigerator. The absorption refrigerator provides cool air for the interior space of the vehicle. Between finishing the steam reforming reaction and flowing into the fuel cell, the gases release heat continuously. A Brayton engine is introduced to absorb heat and provide a useful power output. A novel thermodynamic model of the integrated system of the PEMFC, refrigerator, and Brayton engine is established. Expressions for the power output and efficiency of the integrated system are derived. The effects of some key parameters are discussed in detail to attain optimum performance of the integrated system. The simulation results show that when the syngas consumption rate is 4.0 × 10−5 mol s−1cm−2, the integrated system operates in an optimum state, and the product of the efficiency and power density reaches a maximum. In this case, the efficiency and power density of the integrated system are 0.28 and 0.96 J s−1 cm−2, respectively, which are 46% higher than those of a PEMFC.

Thermodynamic Performance Analysis of a New CHP System With Absorption Heat Pump in a Direct Air Cooling Power Plant

2015 ◽  
Author(s):  
Hongsheng Zhang ◽  
Hongbin Zhao ◽  
Zhenlin Li
Keyword(s):  
Heat Pump ◽  
Power Plants ◽  
Waste Heat ◽  
Integrated System ◽  
Exergy Loss ◽  
Conventional Heating ◽  
Design Parameters ◽  
Air Cooling ◽  
Absorption Heat Pump ◽  
Energy And Exergy

A new waste heat recovery scheme based on absorption heat pumps (AHP) applied in CHP (Combined Heat and Power) system was proposed to decrease heating energy consumption of existing CHP systems by recovering waste heat of exhausted steam from a steam turbine of coal-fired direct air cooling units. Based on the establishment of thermodynamic analysis model, through adopting the design parameters of the 135 MW direct air-cooled power plants in China, the performances, especially the exergy losses of the unit as well as its subsystems mainly including six parts at different heating modes were obtained at one specific load. Compared with conventional heating mode, when the thermoelectric ratio is 100%, the power output increases around 3.81 MW, coal consumption rate decreases 11.69 g/(kW·h) and total exergy loss decreases 6.892 MW under 100% THA load, while the energy and exergy efficiencies of the integrated system increase 1.29 % and 1.25 %, respectively. Additionally, the change laws of total exergy loss, energy and exergy efficiency of integrated system at different loads also were studied. The results provide not only theory basis and scientific support for the design of the coal-fired power plants with absorption heat pump recovering waste heat, but also a new scheme of energy saving and optimization for the units.

scholarly journals Energy and Exergy Efficiency Analysis of Fluid Flow and Heat Transfer in Sinter Vertical Cooler

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4522
Author(s):  
Zude Cheng ◽  
Haitao Wang ◽  
Junsheng Feng ◽  
Yongfang Xia ◽  
Hui Dong
Keyword(s):  
Heat Transfer ◽  
Energy Efficiency ◽  
Fluid Flow ◽  
Waste Heat ◽  
Exergy Efficiency ◽  
Inlet Temperature ◽  
Operational Parameters ◽  
Flow And Heat Transfer ◽  
Maximum Value ◽  
Energy And Exergy

In order to fully understand the energy and exergy transfer processes in sinter vertical coolers, a simulation model of the fluid flow and heat transfer in a vertical cooler was established, and energy and exergy efficiency analyses of the gas–solid heat transfer in a vertical cooler were conducted in detail. Based on the calculation method of the whole working condition, the suitable operational parameters of the vertical cooler were obtained by setting the net exergy efficiency in the vertical cooler as the indicator function. The results show that both the quantity of sinter waste heat recovery (SWHR) and energy efficiency increased as the air flow rate (AFR) increased, and they decreased as the air inlet temperature (AIT) increased. The increase in the sinter inlet temperature (SIT) resulted in an increase in the quantity of SWHR and a decrease in energy efficiency. The air net exergy had the maximum value as the AFR increased, and it only increased monotonically as the SIT and AIT increased. The net exergy efficiency reached the maximum value as the AFR and AIT increased, and the increase in the SIT only resulted in a decrease in the net exergy efficiency. When the sinter annual production of a 360 m2 sintering machine was taken as the processing capacity of the vertical cooler, the suitable operational parameters of the vertical cooler were 190 kg/s for the AFR, and 353 K for the AIT.

scholarly journals Modeling and Simulation of a Proton Exchange Membrane Fuel Cell Alongside a Waste Heat Recovery System Based on the Organic Rankine Cycle in MATLAB/SIMULINK Environment

2021 ◽  
Vol 13 (3) ◽  
pp. 1218
Author(s):  
Sharjeel Ashraf Ansari ◽  
Mustafa Khalid ◽  
Khurram Kamal ◽  
Tahir Abdul Hussain Ratlamwala ◽  
Ghulam Hussain ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Waste Heat Recovery ◽  
Proton Exchange Membrane ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Proton Exchange ◽  
Waste Heat Recovery System ◽  
Recovery System ◽  
Exchange Membrane

The proton exchange membrane fuel cell (PEMFC) is the fastest growing fuel cell technology on the market. Due to their sustainable nature, PEMFCs are widely adopted as a renewable energy resource. Fabricating a PEMFC is a costly process; hence, mathematical modeling and simulations are necessary in order to fully optimize its performance. Alongside this, the feasibility of a waste heat recovery system based on the organic Rankine cycle is also studied and power generation for different operating conditions is presented. The fuel cell produces a power output of 1198 W at a current of 24A. It has 50% efficiency and hence produces an equal amount of waste heat. That waste heat is used to drive an organic Rankine cycle (ORC), which in turn produces an additional 428 W of power at 35% efficiency. The total extracted power hence stands at 1626 W. MATLAB/Simulink R2016a is used for modeling both the fuel cell and the organic Rankine cycle.

scholarly journals Energy and Exergy Analyses of Tube Banks in Waste Heat Recovery Applications

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2094 ◽  
Author(s):  
Mustafa Erguvan ◽  
David MacPhee
Keyword(s):  
Energy Efficiency ◽  
Reynolds Number ◽  
Heat Recovery ◽  
Waste Heat ◽  
Cross Flow ◽  
Exergy Efficiency ◽  
Circular Cylinders ◽  
Published Data ◽  
Energy And Exergy ◽  
Exergy Analyses

In this study, energy and exergy analyses have been investigated numerically for unsteady cross-flow over heated circular cylinders. Numerous simulations were conducted varying the number of inline tubes, inlet velocity, dimensionless pitch ratios and Reynolds number. Heat leakage into the domain is modeled as a source term. Numerical results compare favorably to published data in terms of Nusselt number and pressure drop. It was found that the energy efficiency varies between 72% and 98% for all cases, and viscous dissipation has a very low effect on the energy efficiency for low Reynolds number cases. The exergy efficiency ranges from 40–64%, and the entropy generation due to heat transfer was found to have a significant effect on exergy efficiency. The results suggest that exergy efficiency can be maximized by choosing specific pitch ratios for various Reynolds numbers. The results could be useful in designing more efficient heat recovery systems, especially for low temperature applications.

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