Deformable-volume-based thermal-hydraulic model for a tanks-in-series water–gas system in a vertically stratified flow. Part I: Under adiabatic conditions

2010 ◽  
Vol 240 (7) ◽  
pp. 1739-1747 ◽  
Author(s):  
Jae-Kwang Seo ◽  
Goon-Cherl Park ◽  
Juhyeon Yoon
Keyword(s):  
Stratified Flow ◽  
Hydraulic Model ◽  
Adiabatic Conditions ◽  
Gas System ◽  
In Series ◽  
Flow Part ◽  
Water Gas

scholarly journals Production of Fuels and Chemicals from a CO2/H2 Mixture

Reactions ◽  
2020 ◽  
Vol 1 (2) ◽  
pp. 130-146
Author(s):  
Yali Yao ◽  
Baraka Celestin Sempuga ◽  
Xinying Liu ◽  
Diane Hildebrandt
Keyword(s):  
Co2 Hydrogenation ◽  
Water Gas Shift ◽  
Liquid Fuels ◽  
Saturated Hydrocarbons ◽  
Reverse Water Gas Shift ◽  
Cu Catalyst ◽  
In Series ◽  
Fuels And Chemicals ◽  
Water Gas ◽  
Aspen Simulation

In order to explore co-production alternatives, a once-through process for CO2 hydrogenation to chemicals and liquid fuels was investigated experimentally. In this approach, two different catalysts were considered; the first was a Cu-based catalyst that hydrogenates CO2 to methanol and CO and the second a Fisher–Tropsch (FT) Co-based catalyst. The two catalysts were loaded into different reactors and were initially operated separately. The experimental results show that: (1) the Cu catalyst was very active in both the methanol synthesis and reverse-water gas shift (R-WGS) reactions and these two reactions were restricted by thermodynamic equilibrium; this was also supported by an Aspen plus simulation of an (equilibrium) Gibbs reactor. The Aspen simulation results also indicated that the reactor can be operated adiabatically under certain conditions, given that the methanol reaction is exothermic and R-WGS is endothermic. (2) the FT catalyst produced mainly CH4 and short chain saturated hydrocarbons when the feed was CO2/H2. When the two reactors were coupled in series and the presence of CO in the tail gas from the first reactor (loaded with Cu catalyst) significantly improves the FT product selectivity toward higher carbon hydrocarbons in the second reactor compared to the standalone FT reactor with only CO2/H2 in the feed.

The development of horizontal boundary layers in stratified flow. Part 2. Diffusive flow

1970 ◽  
Vol 42 (3) ◽  
pp. 513-525 ◽  
Author(s):  
L. G. Redekopp
Keyword(s):  
Boundary Layer ◽  
Boundary Layers ◽  
Horizontal Plane ◽  
Stratified Flow ◽  
First Approximation ◽  
Diffusive Flow ◽  
Buoyancy Forces ◽  
Flow Part ◽  
And Diffusion

The boundary layer on the upper surface of a horizontal plane in a diffusive, stratified flow is examined. The analysis shows that density diffusion increases the role of the buoyancy forces and causes a significant change in the properties of the boundary layer when compared to the non-diffusive case. A uniformly valid first approximation for moderate Russell numbers is derived, and the effects of buoyancy and diffusion are evaluated by solving the resulting equations numerically.

Effect of baffles on nitrification in aerated facultative lagoons in a cold climate

2007 ◽  
Vol 55 (11) ◽  
pp. 73-79
Author(s):  
D. Houweling ◽  
F. Chazarenc ◽  
R. Leduc ◽  
Y. Comeau
Keyword(s):  
Flow Regime ◽  
Plug Flow ◽  
Hydraulic Model ◽  
Cold Climate ◽  
Tracer Studies ◽  
Model Based ◽  
Biokinetic Model ◽  
Hydraulic Regime ◽  
In Series ◽  
Simulation Results

Tracer studies performed in two aerated facultative lagoons indicate some bypass and an overall hydraulic regime close to completely-mixed. Results were used to calibrate a hydraulic model based on the tanks-in-series approach. The hydraulic model was combined with a simple “death-regeneration” biokinetic model to simulate seasonal nitrification as observed over a three year period. Modifications were made to the hydraulic model to represent the effect of baffle installations to 1) eliminate bypass and 2) impose a plug-flow regime. Simulation results indicate there is some gain to eliminating bypass but that imposing a plug-flow regime would increase biomass washout rates and hinder nitrification.

An Investigation on Mechanism of Droplet Generation in High Inertial Gaseous Flow

2019 ◽  
Author(s):  
Xinyu Yao ◽  
Zhenyu Liu ◽  
Huiying Wu
Keyword(s):  
Gas Flow ◽  
Channel Wall ◽  
Droplet Generation ◽  
Generation Process ◽  
Visualization Experiment ◽  
Gas System ◽  
Inertial Flow ◽  
Detachment Time ◽  
Water Gas ◽  
Droplet Detachment

Abstract Droplet generation involving high inertial gas flow in a T-junction microchannel was experimentally and numerically studied in this work. The effect of high inertial flow on the water droplet generation was investigated based on the obtained results. At various gas Reynold (Re) numbers and liquid Capillary (Ca) numbers, the unique flow regime mapping including squeezing, dripping and jetting was observed. It was found that stable aqueous droplets are generated in the squeezing and dripping flow regimes. Visualization experiment shows that the morphology of droplets generated in the water-gas system is different from that in the traditional water-oil system. As the Re number increases or the Ca number decreases, the droplet length decreases. Increasing both Re number and Ca number can increase the detachment frequency. Based on the 3D VOF simulations, the droplet attachment to one of the channel wall during the pinch-off period and the rebound of liquid phase after droplet detachment was observed. Droplet size, detachment time and droplet generation frequency were then analyzed for the droplet generation. The dominant detachment mechanism during the whole droplet generation process was also discussed in this work.

The development of horizontal boundary layers in stratified flow. Part 1. Non-diffusive flow

1970 ◽  
Vol 42 (3) ◽  
pp. 497-511 ◽  
Author(s):  
R. E. Kelly ◽  
L. G. Redekopp
Keyword(s):  
Boundary Layer ◽  
Equations Of Motion ◽  
Boussinesq Equations ◽  
Stratified Flow ◽  
Relative Magnitude ◽  
Dimensional Parameter ◽  
Horizontal Boundary ◽  
Basic Parameters ◽  
Flow Part ◽  
Two Parameters

The development of the boundary layer on the upper surface of a horizontal flat plate in a non-diffusive, stratified flow is described. It is shown that the flow can be characterized by two basic parameters, the Reynolds (RL) and Russell (RuL) numbers, and that, depending on the relative magnitude of these two parameters, three different régimes of flow can be defined. The delineation of these régimes and the description of the flow in each of them is obtained by deriving a uniformly valid first approximation to the Boussinesq equations of motion for a flow contained in the two-dimensional parameter spaceRuL> 0,RL> 1. The critical stratification for the self-blocking of a horizontal boundary layer is shown to be given by the conditionRuL=O(RL½).

Sign in / Sign up

Export Citation Format

Share Document