scholarly journals CFD Steady Model Applied to a Biomass Boiler Operating in Air Enrichment Conditions

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2513
Author(s):  
Miguel Gómez ◽  
Rubén Martín ◽  
Joaquín Collazo ◽  
Jacobo Porteiro
Keyword(s):  
Gas Flow ◽  
Chemical Species ◽  
Experimental Tests ◽  
Packed Bed ◽  
Accurate Method ◽  
Combustion Products ◽  
Energy Performance ◽  
Thermal Conversion ◽  
Computational Effort ◽  
Operating Conditions

A numerical model is proposed to perform CFD simulations of biomass boilers working in different operating conditions and analyse the results with low computational effort. The model is based on steady fluxes that represent the biomass thermal conversion stages through the conservation of mass, energy, and chemical species in the packed bed region. The conversion reactions are combined with heat and mass transfer submodels that release the combustion products to the gas flow. The gas flow is calculated through classical finite volume techniques to model the transport and reaction phenomena. The overall process is calculated in a steady state with a fast, efficient, and reasonably accurate method, which allows the results to converge without long computation times. The modelling is applied to the simulation of a 30 kW domestic boiler, and the results are compared with experimental tests with reasonably good results for such a simple model. The model is also applied to study the effect of air enrichment in boiler performance and gas emissions. The boiler operation is simulated using different oxygen concentrations that range from 21% to 90% in the feeding air, and parameters such as the heat transferred, fume temperatures, and emissions of CO, CO2, and NOx are analysed. The results show that with a moderated air enrichment of 40% oxygen, the energy performance can be increased by 8%, CO emissions are noticeably reduced, and NOx remains practically stable.

scholarly journals Thermodynamic modelling of the lead sintering roasting process

2019 ◽  
Vol 55 (1) ◽  
pp. 21-29
Author(s):  
Sánchez Rojas ◽  
Romero Serrano ◽  
Hernández Ramírez ◽  
Rodríguez López ◽  
Guzmán Almaguer ◽  
...  
Keyword(s):  
Gas Flow ◽  
Chemical Species ◽  
Packed Bed ◽  
Operating Conditions ◽  
Sintering Process ◽  
Gaseous Species ◽  
Proposed Model ◽  
Roasting Process ◽  
Simulation Strategy ◽  
Experimental Trials

This work proposes a simulation strategy of the lead sintering process assuming that it takes place in a horizontally moving packed bed with transverse air flow. Some local chemical reactions occur at rates that depend on the temperature, and chemical species formed in one volume stage will flow for further reaction in other stages. To simulate this process, the model reactor is divided into a number of sequential stages. Condensed species flow horizontally, and gaseous species leave each stage vertically. The compositions and temperatures of the species are calculated considering that the local thermodynamic equilibrium is reached in each stage without external heat transfer, apart from the gas flow, before moving on to the next stage. The model calculates the temperature profile along the sintering machine, the compositions of the sinter and the exhaust gas. The results of the proposed model were compared with sinter pot experimental trials and a reasonably good agreement was obtained. This model can be used to optimize the operating conditions of the lead sintering process.

scholarly journals Experimental Assessment of Energy Performance and Emissions of a Residential Microcogenerator

2014 ◽  
Vol 1 (2) ◽  
pp. 48 ◽  
Author(s):  
Giovanni Angrisani ◽  
Carlo Roselli ◽  
Maurizio Sasso ◽  
Peter Tzscheutschler
Keyword(s):  
Energy Saving ◽  
High Efficiency ◽  
Thermal Power ◽  
Experimental Tests ◽  
Energy Performance ◽  
Primary Energy ◽  
Economic Feasibility ◽  
Operating Conditions ◽  
Hot Water ◽  
Test Facility

Microcogeneration can guarantee sensible primary energy savings and greenhouse gas emissions reductions in the residential sector. In this paper, the results of experimental tests carried out on a microcogenerator (5.5 kW electric power and 14.8 kW thermal power) based on a natural gas fuelled internal combustion engine, integrated with a condensing boiler, have been analyzed. Tests have been performed out at Institute for Energy Economy and Application Technology (IfE) of Technical University of Munich (Germany). The test facility allowed to simulate the thermal energy requirements of a real residential application, represented by a Multi Family House consisting of 10 apartments, and to evaluate the energy flows of the conversion devices in actual operating conditions. Four type days, characteristic of Mediterranean climatic conditions, have been used to define space heating and domestic hot water user’s requirements. Experimental tests have been performed to implement energy and environmental analysis, comparing the system consisting of cogenerator and integration boiler with a reference system. Results showed that the former can achieve a primary energy saving of about 6%, and CO2 equivalent emissions reduction of about 12%. Finally, the algorithm defined by the European Directive on the promotion of high efficiency cogeneration has been implemented; it demonstrated that the primary energy saving is well above the limit value prescribed by the Directive. Therefore the cogeneration plant can access support mechanisms that can help to achieve the economic feasibility of the system, besides energy and environmental benefits.

Decomposition of Toluene, o-Xylene, Trichloroethylene, and Their Mixture Using a BaTiO3 Packed-Bed Plasma Reactor

1996 ◽  
Vol 1 (1) ◽  
Author(s):  
Toshiaki Yamamoto ◽  
Jen-Shih Chang ◽  
Alex A Berezin ◽  
Hitoshi Kohno ◽  
Shigeo Honda ◽  
...  
Keyword(s):  
Gas Flow ◽  
Plasma Reactor ◽  
Nonthermal Plasma ◽  
Packed Bed ◽  
Operating Conditions ◽  
Destruction Efficiency ◽  
Volatile Organic ◽  
Reactor Operating ◽  
Reactant Conversion ◽  
Plasma Technologies

AbstractNonthermal plasma technologies offer an innovative approach to the problem of decomposing various volatile organic compounds (VOCs). We focused on an AC-energized ferroelectric packed-bed plasma reactor to study the decomposition/destruction efficiency and byproduct analysis for toluene, o-xylene, trichloroethylene, and their mixture from 50 to 230 ppm in dry air. The effects of gas flow rate, concentration, moisture content, and reactor operating conditions on the decomposition and analysis of reactant conversion for each VOC were investigated for suitable applications of the emerging technology. Laboratory-scale packed-bed plasma technology was successfully demonstrated for the application of VOC control in semiconductor clean room environments.

Modeling the Transient VOC (toluene) Oxidation in a Packed-Bed Catalytic Reactor

2016 ◽  
Vol 14 (6) ◽  
pp. 1177-1185 ◽  
Author(s):  
Tristán Esparza-Isunza ◽  
Felipe López-Isunza
Keyword(s):  
Heat Transport ◽  
Gas Flow ◽  
Packed Bed ◽  
Operating Conditions ◽  
Packed Bed Reactor ◽  
Phase System ◽  
Transport Parameter ◽  
Catalytic Reactor ◽  
Toluene Oxidation ◽  
Reaction Fronts

Abstract A model is developed to study the transient behavior of a non-isothermal, non-adiabatic packed-bed reactor during VOC (toluene) oxidation with air on a mixed-oxide catalyst via Mars-van Krevelen kinetic scheme. The aim is to find a safe reactor design and operating conditions for VOC elimination, which has been collected in a battery of adsorption units from dilute VOC streams. Once each adsorption column is saturated, a non-isothermal desorption takes place, and the gas stream exiting the sequence of VOC desorption columns feeds continuously the catalytic reactor for VOC elimination. The reactor model describes a 2D two-phase system interacting through the gas-solid interphase, including convection and axial and radial dispersions of mass and heat. The simulations show that the gas flow velocity, and reactor and particle diameters, are key parameters to achieve a safe design, and that traveling reaction fronts in the packed-bed exist when a series of reversible stepwise changes are performed in the concentration and temperature at the feed, as a result of the transient balance between heat generation and heat elimination along the packed-bed. When comparing the perturbation in VOC concentration at the feed versus those in temperature, a large parametric sensitivity is observed for the latter case without the presence of multiple steady states. Due to the uncertainty in the values of the effective heat transport parameters, transient responses of different magnitude are observed for the same operating conditions when using heat transport parameter of different magnitude.

scholarly journals Thermal Characterization of Different Insulating Materials via Experimental Analysis in a Guarded Hot Box

2021 ◽  
Vol 65 (2-4) ◽  
pp. 230-235
Author(s):  
Tullio de Rubeis ◽  
Giovanni Pasqualoni ◽  
Domenica Paoletti ◽  
Dario Ambrosini
Keyword(s):  
Experimental Tests ◽  
Thermal Characterization ◽  
Energy Performance ◽  
Building Envelope ◽  
Expanded Polystyrene ◽  
Operating Conditions ◽  
Insulating Materials ◽  
U Value ◽  
Cold Chamber

The thermal characterization of building envelope materials is a crucial phase in understanding the building energy performance, and it is commonly evaluated through the thermal transmittance, often synthetically indicated as U-value. There are several ways to experimentally assess the U-value of insulating materials and multi-layers systems, usually defined by means of experimental in-situ heat flux measurements, where, however, a considerable variation of the boundary conditions may occur, making the measurement difficult. In this work, the experimental thermal characterization of different insulating materials applied to an X-lam wall is presented. The analysis is carried out using a Guarded Hot Box, which allowed to reproduce real, repeatable, and controlled operating conditions. Two different insulating materials were selected: expanded polystyrene (EPS) with graphite and hemp. The experimental tests were carried out by imposing a temperature difference reproducing the common operating conditions (0°C in cold chamber and 20°C in hot chamber). Steady-state conditions (constant temperature in the chambers) have been imposed to determine the thermal properties of the multi-layer systems. The tests, lasted 72 hours each, showed U-values equal to 0.15 W/m2K ± 3.1% for EPS with graphite and 0.19 W/m2K ± 3.1% for hemp.

Cometabolism in biofilm reactors

1995 ◽  
Vol 31 (1) ◽  
pp. 215-225 ◽  
Author(s):  
Gerald E. Speitel ◽  
Robert L. Segar
Keyword(s):  
Chlorinated Solvents ◽  
Packed Bed ◽  
Operating Conditions ◽  
Mixed Cultures ◽  
Treatment Technology ◽  
Hydraulic Residence Time ◽  
Slow Growth Rate ◽  
Biofilm Reactors ◽  
Aerobic Cometabolism ◽  
Degrading Bacteria

Aerobic cometabolism of chlorinated aliphatic solvents in biofilm reactors is a potential treatment technology for contaminated water and air streams. This research investigated cometabolism by pure and mixed cultures of methanotrophs and mixed cultures of phenol-degrading bacteria. Initial experiments with continuous-flow, packed-bed bioreactors proved unsuccessful; therefore, the major focus of the work was on sequencing biofilm reactors, which cycle between two modes of operation, degradation of chlorinated solvents and rejuvenation of the microbial population. Particular success was obtained with a mixed culture of phenol degraders in the treatment of chlorinated ethenes (e.g., trichloroethylene - TCE). Under the best operating conditions, 90% removal of TCE occurred at a 14-minute packed-bed hydraulic residence time. The bioreactors required only two, 1.5 h biomass rejuvenation periods per day to sustain this removal. Experiments with Methylosinus trichosporium OB3b were less successful because of the organism's slow growth rate, relatively poor ability to attach to surfaces, and its inability to successfully compete with other methanotrophs in the bioreactor environment. Overall, however, the research demonstrated the potential attractiveness of sequencing biofilm reactors in treating water contaminated with chlorinated solvents.

scholarly journals Comprehensive Parameters Identification and Dynamic Model Validation of Interior-Mount Line-Start Permanent Magnet Synchronous Motors

Machines ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 4 ◽  
Author(s):  
Luqman S. Maraaba ◽  
Zakariya M. Al-Hamouz ◽  
Abdulaziz S. Milhem ◽  
Ssennoga Twaha
Keyword(s):  
Mathematical Model ◽  
Permanent Magnet ◽  
High Efficiency ◽  
Experimental Tests ◽  
Induction Machines ◽  
Test Methods ◽  
Operating Conditions ◽  
Test Method ◽  
Permanent Magnet Synchronous Motors ◽  
Synchronous Motors

The application of line-start permanent magnet synchronous motors (LSPMSMs) is rapidly spreading due to their advantages of high efficiency, high operational power factor, being self-starting, rendering them as highly needed in many applications in recent years. Although there have been standard methods for the identification of parameters of synchronous and induction machines, most of them do not apply to LSPMSMs. This paper presents a study and analysis of different parameter identification methods for interior mount LSPMSM. Experimental tests have been performed in the laboratory on a 1-hp interior mount LSPMSM. The measurements have been validated by investigating the performance of the machine under different operating conditions using a developed qd0 mathematical model and an experimental setup. The dynamic and steady-state performance analyses have been performed using the determined parameters. It is found that the experimental results are close to the mathematical model results, confirming the accuracy of the studied test methods. Therefore, the output of this study will help in selecting the proper test method for LSPMSM.

scholarly journals Sensitivity Analysis of OTEC-CC-MX-1 kWe Plant Prototype

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2585
Author(s):  
Jessica Guadalupe Tobal-Cupul ◽  
Estela Cerezo-Acevedo ◽  
Yair Yosias Arriola-Gil ◽  
Hector Fernando Gomez-Garcia ◽  
Victor Manuel Romero-Medina
Keyword(s):  
Sensitivity Analysis ◽  
Experimental Tests ◽  
Caribbean Sea ◽  
Ocean Model ◽  
Operating Conditions ◽  
Working Fluid ◽  
Ocean Energy ◽  
Mexican Caribbean ◽  
Water Temperature Data ◽  
Mass Flows

The Mexican Caribbean Sea has potential zones for Ocean Thermal Energy Conversion (OTEC) implementation. Universidad del Caribe and Instituto de Ciencias del Mar y Limnologia, with the support of the Mexican Centre of Innovation in Ocean Energy, designed and constructed a prototype OTEC plant (OTEC-CC-MX-1 kWe), which is the first initiative in Mexico for exploitation of this type of renewable energy. This paper presents a sensitivity analysis whose objective was to know, before carrying out the experimental tests, the behavior of OTEC-CC-MX-1 kWe regarding temperature differences, as well as the non-possible operating conditions, which allows us to assess possible modifications in the prototype installation. An algorithm was developed to obtain the inlet and outlet temperatures of the water and working fluid in the heat exchangers using the monthly surface and deep-water temperature data from the Hybrid Coordinate Ocean Model and Geographically Weighted Regression Temperature Model for the Mexican Caribbean Sea. With these temperatures, the following were analyzed: fluctuation of thermal efficiency, mass flows of R-152a and water and power production. By analyzing the results, we verified maximum and minimum mass flows of water and R-152a to produce 1 kWe during a typical year in the Mexican Caribbean Sea and the conditions when the production of electricity is not possible for OTEC-CC-MX-1 kWe.

The analysis on the influence of mixed sliding-rolling motion mode to precision degradation of ball screw

2021 ◽  
pp. 095440622098201
Author(s):  
Qiang Cheng ◽  
Baobao Qi ◽  
Hongyan Chu ◽  
Ziling Zhang ◽  
Zhifeng Liu ◽  
...  
Keyword(s):  
Structural Parameters ◽  
Experimental Tests ◽  
Theoretical Models ◽  
Operating Conditions ◽  
Ball Screw ◽  
Rolling Motion ◽  
Degradation Model ◽  
Sliding Motion ◽  
Factors Analysis ◽  
Motion Mode

The combination of sliding/rolling motion can influence the degree of precision degradation of ball screw. Precision degradation modeling and factors analysis can reveal the evolution law of ball screw precision. This paper presents a precision degradation model for factors analysis influencing precision due to mixed sliding-rolling motion. The precision loss model was verified through the comparison of theoretical models and experimental tests. The precision degradation due to rolling motion between the ball and raceway accounted for 29.09% of the screw precision loss due to sliding motion. Additionally, the total precision degradation due to rolling motion accounted for 21.03% of the total sliding precision loss of the screw and nut, and 17.38% of the overall ball screw precision loss under mixed sliding-rolling motion. In addition, the effects of operating conditions and structural parameters on precision loss were analyzed. The sensitivity coefficients of factors influencing were used to quantitatively describe impact degree on precision degradation.

scholarly journals Methodology for Selecting the Operating Conditions of a Vibration Generator Used in the Hot-Dip Galvanizing Process

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2042
Author(s):  
Wojciech Kacalak ◽  
Igor Maciejewski ◽  
Dariusz Lipiński ◽  
Błażej Bałasz
Keyword(s):  
Simulation Model ◽  
Asynchronous Motor ◽  
Experimental Tests ◽  
Suspension System ◽  
Operating Conditions ◽  
Test Results ◽  
Forced Simulation

A simulation model and the results of experimental tests of a vibration generator in applications for the hot-dip galvanizing process are presented. The parameters of the work of the asynchronous motor forcing the system vibrations were determined, as well as the degree of unbalance enabling the vibrations of galvanized elements weighing up to 500 kg to be forced. Simulation and experimental tests of the designed and then constructed vibration generator were carried out at different intensities of the unbalanced rotating mass of the motor. Based on the obtained test results, the generator operating conditions were determined at which the highest values of the amplitude of vibrations transmitted through the suspension system to the galvanized elements were obtained.

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