scholarly journals Power-to-Green Methanol via CO2 Hydrogenation—A Concept Study Including Oxyfuel Fluidized Bed Combustion of Biomass

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4638
Author(s):  
Simon Pratschner ◽  
Pavel Skopec ◽  
Jan Hrdlicka ◽  
Franz Winter
Keyword(s):  
Large Scale ◽  
Positive Impact ◽  
Renewable Energy Sources ◽  
Air Separation ◽  
Model Parameters ◽  
Processing Unit ◽  
Fluidized Bed Combustion ◽  
Separation Unit ◽  
Oxyfuel Combustion ◽  
Wind Park

A revolution of the global energy industry is without an alternative to solving the climate crisis. However, renewable energy sources typically show significant seasonal and daily fluctuations. This paper provides a system concept model of a decentralized power-to-green methanol plant consisting of a biomass heating plant with a thermal input of 20 MWth. (oxyfuel or air mode), a CO2 processing unit (DeOxo reactor or MEA absorption), an alkaline electrolyzer, a methanol synthesis unit, an air separation unit and a wind park. Applying oxyfuel combustion has the potential to directly utilize O2 generated by the electrolyzer, which was analyzed by varying critical model parameters. A major objective was to determine whether applying oxyfuel combustion has a positive impact on the plant’s power-to-liquid (PtL) efficiency rate. For cases utilizing more than 70% of CO2 generated by the combustion, the oxyfuel’s O2 demand is fully covered by the electrolyzer, making oxyfuel a viable option for large scale applications. Conventional air combustion is recommended for small wind parks and scenarios using surplus electricity. Maximum PtL efficiencies of ηPtL,Oxy = 51.91% and ηPtL,Air = 54.21% can be realized. Additionally, a case study for one year of operation has been conducted yielding an annual output of about 17,000 t/a methanol and 100 GWhth./a thermal energy for an input of 50,500 t/a woodchips and a wind park size of 36 MWp.

Analytical Formulation of the Performance of the Allam Power Cycle

2020 ◽  
Author(s):  
Yousef Haseli
Keyword(s):  
Power Plants ◽  
Fossil Fuels ◽  
Air Separation ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Separation Unit ◽  
Power Cycle ◽  
Functional Relationships ◽  
Oxyfuel Combustion ◽  
Co2 Flow

Abstract Thermal power plants operating on fossil fuels emit a considerable amount of polluting gases including carbon dioxide and nitrogen oxides. Several technologies have been developed or under development to avoid the emissions of, mainly, CO2 that are formed as a result of air-fuel combustion. While post-combustion capture methods are viable solutions for reduction of CO2 in the existing power plants, implementation of the concept of oxyfuel combustion in future power cycles appears to be a promising technique for clean power generation from fossil fuels. A novel power cycle that employs oxyfuel combustion method has been developed by NET Power. Known as the Allam cycle, it includes a turbine, an air separation unit (ASU), a combustor, a recuperator, a water separator, CO2 compression with intercooling and CO2 pump. (Over 90% of the supercritical CO2 flow is recycled back to the cycle as the working fluid, and the rest is extracted for further processing and storage. The present paper introduces a simplified thermodynamic analysis of the Allam power cycle. Analytical expressions are derived for the net power output, optimum turbine inlet temperature (TIT), and the molar flowrate of the recycled CO2 flow. The study aims to provide a theoretical framework to help understand the functional relationships between the various operating parameters of the cycle. The optimum TIT predicted by the presented expression is 1473 K which is fairly close to that reported by the cycle developers.

scholarly journals Clean Hydrogen and Ammonia Synthesis in Paraguay from the Itaipu 14 GW Hydroelectric Plant

2019 ◽  
Vol 3 (4) ◽  
pp. 87
Author(s):  
Massimo Rivarolo ◽  
Gustavo Riveros-Godoy ◽  
Loredana Magistri ◽  
Aristide F. Massardo
Keyword(s):  
Large Scale ◽  
Ammonia Synthesis ◽  
Hydroelectric Plant ◽  
Electrical Energy ◽  
Economic Feasibility ◽  
Air Separation ◽  
Production Costs ◽  
Methane Steam Reforming ◽  
Hydroelectric Power ◽  
Separation Unit

This paper aims at investigating clean hydrogen production from the large size (14 GW) hydroelectric power plant of Itaipu, located on the border between Paraguay and Brazil, the two countries that own and manage the plant. The hydrogen, produced by a water electrolysis process, is converted into ammonia through the well-known Haber-Bosch process. Hydraulic energy is employed to produce H2 and N2, respectively, from a large-scale electrolysis system and an air separation unit. An economic feasibility analysis is performed considering the low electrical energy price in this specific scenario and that Paraguay has strong excess of renewable electrical energy but presents a low penetration of electricity. The proposal is an alternative to increase the use of electricity in the country. Different plant sizes were investigated and, for each of them, ammonia production costs were determined and considered as a term of comparison with traditional ammonia synthesis plants, where H2 is produced from methane steam reforming and then purified. The study was performed employing a software developed by the authors’ research group at the University of Genoa. Finally, an energetic, environmental, and economic comparison with the standard production method from methane is presented.

Numerical Investigation of a Cryogenic Liquid Turbine Performance and Flow Behavior

2008 ◽  
Author(s):  
Wei Zhao ◽  
Jinju Sun ◽  
Hezhao Zhu ◽  
Cheng Li ◽  
Guocheng Cai ◽  
...  
Keyword(s):  
Numerical Investigation ◽  
Large Scale ◽  
Flow Behavior ◽  
Cryogenic Liquid ◽  
Air Separation ◽  
Design Flow ◽  
Suction Surface ◽  
Navier Stokes Equation ◽  
Separation Unit ◽  
Turbine Performance

A single stage cryogenic liquid turbine is designed for a large-scale internal compression air-separation unit to replace the Joule-Thompson valve and recover energy from the liquefied air during throttling process. It includes a radial vaned nozzle, and 3-dimensional impeller. Numerical investigation using 3-D incompressible Navier-Stokes Equation together with Spalart-Allmaras turbulence model and mixing plane approach at the impeller and stator interface are carried out at design and off-design flow. At design condition, recovered shaft power has amounted to 185.87 kW, and pressure in each component decreases smoothly and reaches to the expected scale at outlet. At small flow rates, flow separation is observed near the middle section of blade suction surface, which may cause local vaporization and even cavitation. To further improve the turbine flow behavior and performance, geometry parametric study is carried out. Influence of radial gap between impeller and nozzle blade rows, and nozzle stagger angle on turbine performance are investigated and clarified. Results arising from the present study provide some guidance for cryogenic liquid turbine optimal design.

Influence of Impeller Fairing Cone Geometry on Cavitating Flow Behavior in a Cryogenic Liquid Turbine Expander

2016 ◽  
Author(s):  
Ke Wang ◽  
Jinju Sun ◽  
Peng Song ◽  
Changjiang Huo
Keyword(s):  
Large Scale ◽  
Bubble Dynamics ◽  
Flow Behavior ◽  
Hydraulic Turbine ◽  
Sensitivity Study ◽  
Cryogenic Liquid ◽  
Cavitating Flow ◽  
Air Separation ◽  
Separation Unit ◽  
Thermodynamic Effect

A single stage cryogenic liquid turbine expander is developed as a replacement for traditional Joule-Thomson valves used in the large-scale internal compression air-separation unit for the purpose of energy saving. Similar to the conventional hydraulic turbine, detrimental swirling and cavitation flow is also encountered at turbine expander impeller exit and its successive diffuser tube, but due to significant thermodynamic effect of cryogenic fluid flow, it is much more complicated than the conventional hydraulic turbine. In the present study, cavitating flow mechanism of the turbine expander is investigated first with a combination of the homogenous multiphase mixture model and the Rayleigh-Plesset model, where the former treats liquid and gas as a continuum mixture and the latter depicts the bubble dynamics. Then sensitivity study is conducted for the impeller fairing cone geometry on suppression of cavitating flow. The following are demonstrated: with a use of the fairing cone, flow behavior near and downstream the impeller exit is significantly improved, where the low static pressure region is reduced and the local temperature rise decreases, subsequently the cavitating flow is effectively suppressed. The cavitating flow is sensitive to a tuning of the fairing cone geometry, and an optimal design of the cone geometry is essential.

Development of Parts Family Manage System Based on PDM in Large-Scale Air Separation Equipment

2012 ◽  
Vol 605-607 ◽  
pp. 288-291
Author(s):  
Rui Zhu ◽  
Guang Meng ◽  
Hong Guang Li
Keyword(s):  
Large Scale ◽  
Design Procedure ◽  
Air Separation ◽  
Practical Significance ◽  
Design Environment ◽  
Separation Unit ◽  
Software Interface ◽  
Database Structure ◽  
Air Separation Unit ◽  
Separation Equipment

Large-scale air separation equipment is used widely in chemical industry. It can provide oxygen, nitrogen and argon for the production process. Based on the deep analysis of the working principle and using equipment, the air separation unit product data management (PDM) system is developed by Visual Basic (VB) in this paper develops. The modularized design procedure and grouping technique (GT) are adopted in this system. The morphological matrix is used to establish their coordination relationship among parts. The system has many characters, such as perfect function, reasonable database structure, and concise software interface layout. Optimizing equipment parts management properly and effectively has important practical significance in designing the subsequent product development work and establishing concurrent design environment of the air separation unit.

Investigation of Impeller Strength for a Cryogenic Liquid Turbine

2010 ◽  
Author(s):  
Yan Ren ◽  
Jinju Sun ◽  
Rongye Zheng ◽  
Peng Song ◽  
Ke Wang
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Centrifugal Force ◽  
Low Temperatures ◽  
Large Scale ◽  
Cryogenic Liquid ◽  
Air Separation ◽  
Design Flow ◽  
Navier Stokes Equation ◽  
Separation Unit

A single stage cryogenic liquid turbine is designed for a large-scale internal compression air-separation unit to replace the Joule-Thompson valve and recover energy from the liquefied air during throttling process. It includes a 3-dimensional impeller, variable geometry nozzle, and asymmetrical volute. Strength evaluation of such a liquid turbine is both essential and complicated, which involves a proper evaluation of stress acting on the components and mechanical property of the chosen materials at low temperature. For metals under low temperatures, brittle fracture of the metal may occur prior to fatigue damage. A comprehensive consideration of low-temperature mechanical properties of materials and mechanical loads (due to hydrodynamic force and centrifugal force) acting on the components is of particular importance. Aluminum alloy 2031 is used for the turbine impeller and its mechanical properties under low temperatures are analyzed. To evaluate the stress acting on the components, numerical investigation using 3-D incompressible Navier-Stokes Equation together with k-epsilon turbulence model and mixing plane approach at rotator-stator interface are carried out at design and off-design flow with different nozzle-vane settings. The obtained pressure force is transformed into hydrodynamic load acting on the solid surface by means of fluid-solid interaction technology, and then used in the FEM (Finite Element Method) structure analysis together with the centrifugal force. Stress distribution of the component is obtained and deformation of the component analyzed. Evaluation of impeller strength is conducted for the cryogenic liquid turbine by combining the foregoing two aspects, and a use of alloy 2031 for the turbine expander is validated.

Parameter Estimation in Modeling of Photovoltaic Panels Based on Datasheet Values

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
Hayrettin Can ◽  
Damla Ickilli
Keyword(s):  
Parameter Estimation ◽  
Large Scale ◽  
Renewable Energy Sources ◽  
Model Parameters ◽  
New Approach ◽  
Numerical Convergence ◽  
Initial Values ◽  
Pv Panel ◽  
Panel Model ◽  
Increasing Demand

The increasing demand for renewable energy sources in recent years has triggered technological advancements in photovoltaic (PV) panels. Widespread use of large-scale PV units has revealed the sensitivity in PV panel modeling needed to estimate the amount of energy produced in different environmental conditions. For the formation of a PV panel model, parameters should be obtained by numerically solving characteristic equations of a transcendental nature. This study preferred using the Newton Raphson (NR) method owing to the suitability of equation structure. It is crucial that numerical solution starts with proper initial values. This study proposes a new approach to identifying initial values in order to decrease calculation time and increase the speed of numerical convergence. The proposed method was used in parameter estimation for different panel models. And, it was observed that owing to this method, the system converged with less iteration and the problem of failing to solve the system because of inappropriate initial values were eliminated. Convergence was obtained and the solution needed less iteration in all models.

scholarly journals System approach to the analysis of an integrated oxy-fuel combustion power plant

2014 ◽  
Vol 35 (3) ◽  
pp. 39-57 ◽  
Author(s):  
Andrzej Ziębik ◽  
Paweł Gładysz
Keyword(s):  
Power Plant ◽  
System Approach ◽  
System Analysis ◽  
Flame Temperature ◽  
Combustion Process ◽  
Fuel Combustion ◽  
Air Separation ◽  
Processing Unit ◽  
Separation Unit ◽  
Direct Energy

Abstract Oxy-fuel combustion (OFC) belongs to one of the three commonly known clean coal technologies for power generation sector and other industry sectors responsible for CO2 emissions (e.g., steel or cement production). The OFC capture technology is based on using high-purity oxygen in the combustion process instead of atmospheric air. Therefore flue gases have a high concentration of CO2. Due to the limited adiabatic temperature of combustion some part of CO2 must be recycled to the boiler in order to maintain a proper flame temperature. An integrated oxy-fuel combustion power plant constitutes a system consisting of the following technological modules: boiler, steam cycle, air separation unit, cooling water and water treatment system, flue gas quality control system and CO2 processing unit. Due to the interconnections between technological modules, energy, exergy and ecological analyses require a system approach. The paper present the system approach based on the ‘input-output’ method to the analysis of the: direct energy and material consumption, cumulative energy and exergy consumption, system (local and cumulative) exergy losses, and thermoecological cost. Other measures like cumulative degree of perfection or index of sustainable development are also proposed. The paper presents a complex example of the system analysis (from direct energy consumption to thermoecological cost) of an advanced integrated OFC power plant.

scholarly journals Exergy Analysis of Liquid Nitrogen Power Cycles

2019 ◽  
Vol 201 ◽  
pp. 01004
Author(s):  
Paweł Wojcieszak
Keyword(s):  
Liquid Nitrogen ◽  
Energy Demand ◽  
Power Plants ◽  
Exergy Analysis ◽  
Renewable Energy Sources ◽  
Air Separation ◽  
Direct Expansion ◽  
Separation Processes ◽  
Separation Unit ◽  
Electrical Grid

Nitrogen is by-product from cryogenic air separation processes used for oxygen production for metallurgy and oxygen-enriched combustion purposes. If the gases are delivered from air separation unit (ASU) in liquid phase, liquid nitrogen (LN2) can be used as energy accumulator for stabilization of electrical grid system with large share of renewable energy sources. When the energy demand is high and not enough electricity is generated in power plants, energy accumulated in LN2 may be recovered in a cryogenic power cycle. In this research complete exergy analysis of liquid nitrogen direct expansion cycle and combined direct expansion/Brayton cycle was performed.

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