The Feasibility Research of Using an Intensified Continuous Mini-Reactor to Replace a Discontinuous Reactor

2011 ◽  
Vol 391-392 ◽  
pp. 894-899
Author(s):  
Shi Li ◽  
Yan Hu ◽  
Xi Ju Zong
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
High Pressure ◽  
Steady State ◽  
Energy Balance ◽  
Mathematic Model ◽  
Reaction Rates ◽  
Design And Optimization ◽  
Feasibility Research ◽  
Three Phase

An intensified continuous mini-reactor is introduced, to replace traditional discontinuous reactor, using in three-phase catalytic slurry hydrogenation. Under high pressure intensification, continuous mini-reactor behaves excellent performances of mass transfer and heat transfer, and presents the advantages of smaller volume, faster reaction rates, higher conversion and no solvent addition. The steady-state mathematic model is established, and the characteristic times of mass transfer and heat transfer are analyzed based on mass balance and energy balance Eq.s, the results can efficiently help the reactor design and optimization.

The Experimental Investigation of Steam Condensation With Non-Condensable Gas Under Natural Convection

2018 ◽  
Author(s):  
Xizhen Ma ◽  
Wen Fu ◽  
Haijun Jia ◽  
Peiyue Li ◽  
Jun Li
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
High Pressure ◽  
Natural Convection ◽  
Heat And Mass Transfer ◽  
Vertical Wall ◽  
Experimental System ◽  
Steam Condensation ◽  
Transfer Coefficients ◽  
Calculation Results

The non-condensable gas is used to keep the pressure stable in the steam-gas pressurizer. The processes of heat and mass transfer during steam condensation in the presence of non-condensable gas play an important role and the thermal hydraulic characteristics in the pressurizer is particularly complicated due to the non-condensable gas. The effects of non-condensable gas on the process of heat and mass transfer during steam condensation were experimental investigated. A steam condensation experimental system under high pressure and natural convection was built and nitrogen was chosen in the experiments. The steam and nitrogen were considered in thermal equilibrium and shared the same temperature in the vessel under natural convection. In the experiments, the factors, for instance, pressure, mass fraction of nitrogen, subcooling of wall and the distribution of nitrogen in the steam, had been taken into account. The rate of heat transfer of steam condensation on the vertical wall with nitrogen was obtained and the heat transfer coefficients were also calculated. The characteristics curve of heat and mass transfer during steam condensation with non-condensable gas under high pressure were obtained and an empirical correlation was introduced to calculated to heat transfer coefficient of steam condensation with nitrogen which the calculation results showed great agreement with the experimental data.

Research Needs: Industrial Spray Processes, Spray Drying, and Heat Transfer

1988 ◽  
Vol 41 (10) ◽  
pp. 365-370 ◽  
Author(s):  
William S. Janna
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
High Pressure ◽  
Spray Drying ◽  
Research Needs ◽  
Comprehensive Model ◽  
Research Topics ◽  
Transfer Processes ◽  
Mass Transfer Processes ◽  
Enhance Mass

A survey of researchers and of manufacturers of spraying, drying, and spray heat transfer equipment was conducted. Those that responded provided descriptions of processes and devices that need developmental attention. Several of these problems are described here (eg, a unifying theory of how atomization takes place; a method of evaluating the performance of a spray used to dissolve air in water to enhance mass transfer processes; a comprehensive model for predicting heat transfer from high pressure sprays; etc). It is concluded that many research topics can be gleaned from industry as needs develop and innovative ways are found for sprays to replace conventional methods.

Comparison of Steady and Unsteady Coupled Heat-Transfer Simulations of a High-Pressure Turbine Blade

2015 ◽  
Author(s):  
Markus Schmidt ◽  
Christoph Starke
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Steady State ◽  
Flow Field ◽  
Film Cooling ◽  
Strong Increase ◽  
Pressure Side ◽  
Turbine Stage ◽  
High Pressure Turbine ◽  
Time Resolved

This article presents results for the coupled simulation of a high-pressure turbine stage in consideration of unsteady hot gas flows. A semi-unsteady coupling process was developed to solve the conjugate heat transfer problem for turbine components of gas turbines. Time-resolved CFD simulations are coupled to a finite element solver for the steady state heat conduction inside of the blade material. A simplified turbine stage geometry is investigated in this paper to describe the influence of the unsteady flow field onto the time-averaged heat transfer. Comparisons of the time-resolved results to steady state results indicate the importance of a coupled simulation and the consideration of the time-dependent flow-field. Different film-cooling configurations for the turbine NGV are considered, resulting in different temperature and pressure deficits in the vane wake. Their contribution to non-linear effects causing the time-averaged heat load to differ from a steady result is discussed to further highlight the necessity of unsteady design methods for future turbine developments. A strong increase in the pressure side heat transfer coefficients for unsteady simulations is observed in all results. For higher film-cooling mass flows in the upstream row, the preferential migration of hot fluid towards the pressure side of a turbine blade is amplified as well, which leads to a strong increase in material temperature at the pressure side and also in the blade tip region.

scholarly journals DIFFUSIVE AND DISPLACIVE PHASE TRANSFORMATIONS UNDER HIGH PRESSURE TORSION

2019 ◽  
Vol 25 (4) ◽  
pp. 230 ◽  
Author(s):  
Boris Straumal ◽  
Askar Kilmametov ◽  
Andrey Mazilkin ◽  
Olga Kogtenkova ◽  
Brigitte Baretzky ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Plastic Deformation ◽  
Grain Size ◽  
High Pressure ◽  
Phase Composition ◽  
Steady State ◽  
Phase Transformations ◽  
High Pressure Torsion ◽  
Dynamic Equilibrium ◽  
Initial State

<p class="AMSmaintext"><span lang="EN-GB">Severe plastic deformation (SPD) can induce various phase transformations. After a certain strain, the dynamic equilibrium establishes between defects production by an external force and their relaxation (annihilation). The grain size, hardness, phase composition etc. in this steady-state does not depend on the initial state of a material and is, therefore, equifinal. In this review we discuss the competition between precipitation and dissolution of precipitates, amorphization and (nano)crystallization, SPD-induced accelerated mass-transfer, allotropic and martensitic transitions and formation of grain boundary phases.</span></p>

Changed Heat and Mass Transfer Evaluation of a Gas-to-Gas Type Membrane Humidifier by Mass Collection

2010 ◽  
Author(s):  
ByungJun Kim ◽  
SangSeok Yu ◽  
YoungDuk Lee ◽  
KookYoung Ahn
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Steady State ◽  
Heat And Mass Transfer ◽  
Humidity Sensor ◽  
Transient State ◽  
Air Flow Rate ◽  
Dry Air ◽  
Mass And Heat Transfer ◽  
Mass Collection

In this paper, a technique of the humidity measurement is developed to identify the performance of membrane humidifier. The technique is designed to measure the performance of membrane humidifier during steady state and transient state. In particular, the measurement technique is very useful to understand dynamic behavior of humidifier because the response of commercial humidity sensor is too slow to capture the transient response of mass and heat transfer through the membrane. Accordingly, the heat and mass transfer characteristics of membrane humidifier are figured out with the experimental analysis. The parameters used in experiment are dry air pressure, humid air temperature and dry air flow rate.

Simultaneous Detection of Hydrodynamics, Mass Transfer and Reaction Rates in a Three-Phase Microreactor

2020 ◽  
Vol 54 (1) ◽  
pp. 48-63 ◽  
Author(s):  
S. Haase ◽  
T. Bauer ◽  
G. Hilpmann ◽  
M. Lange ◽  
M.-M. Ayubi ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Simultaneous Detection ◽  
Reaction Rates ◽  
Three Phase

Study of Heat and Mass Transfer in MgCl2/NH3 Thermochemical Batteries

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Seyyed Ali Hedayat Mofidi ◽  
Kent S. Udell
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Phase Change ◽  
Heat And Mass Transfer ◽  
Waste Heat ◽  
Experimental Studies ◽  
Reaction Rates ◽  
Solid Matrix ◽  
Dominant Factor ◽  
Gaseous Ammonia

Intermittency of sustainable energy or waste heat availability calls for energy storage systems such as thermal batteries. Thermochemical batteries based on a reversible solid–gas (MgCl2–NH3) reactions and NH3 liquid–gas phase change are of specific interest since the kinetics of absorption are fast and the heat transfer rates for liquid–vapor phase change are high. Thus, a thermochemical battery based on reversible reaction between magnesium chloride and ammonia was studied. Two-dimensional experimental studies were conducted on a reactor in which temperature profiles within the solid matrix and pressure and flow rates of gas were obtained during discharging processes. A numerical model based on heat and mass transfer within the salt and salt–gas reactions was developed to simulate the NH3 absorption processes within the solid matrix, and the results were compared with experimental data to determine dominant heat and mass transfer processes within the salt. It is shown that for high permeability salt beds, the reactor uniformly adsorbs gaseous ammonia until the bed reaches the equilibrium temperature, then adsorbs gas near the cooled boundaries as the reaction front moves inward. In that mode, the heat transfer is the dominant factor in determining reaction rates.

Sign in / Sign up

Export Citation Format

Share Document