Safety analysis and risk identification for a tubular reactor using the HAZOP methodology

2006 ◽  
Vol 60 (6) ◽  
Author(s):  
J. Labovský ◽  
L’. Jelemenský ◽  
J. Markoš
Keyword(s):  
Mathematical Modeling ◽  
Steady State ◽  
Ethylene Oxide ◽  
Tubular Reactor ◽  
Computer Code ◽  
Risk Identification ◽  
Process Unit ◽  
Steady State Analysis ◽  
Process Simulator ◽  
Model Approach

AbstractA model approach to Hazard and Operability (HAZOP) analysis is presented based on the mathematical modeling of a process unit where both the steady-state analysis, including the analysis of the steady states multiplicity and stability, and the dynamic simulation are used. Heterogeneous tubular reactor for the ethylene oxide production from ethylene and oxygen was chosen to identify potential hazards for real system. The computer code DYNHAZ was developed consisting of a process simulator and a generator of the HAZOP algorithm.

Analysis of a Convection Loop for GFR Post-LOCA Decay Heat Removal

2004 ◽  
Author(s):  
Wesley C. Williams ◽  
Pavel Hejzlar ◽  
Pradip Saha
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Flow Regime ◽  
Natural Circulation ◽  
Heat Removal ◽  
Computer Code ◽  
Steady State Analysis ◽  
Decay Heat ◽  
Cooling Loops ◽  
State Analysis

A computer code (LOCA-COLA) has been developed at MIT for steady state analysis of convective heat transfer loops. In this work, it is used to investigate an external convection loop for decay heat removal of a post-LOCA GFR. The major finding is that natural circulation cooling of the GFR is feasible under certain circumstances. Both helium and CO2 cooled system components are found to operate in the mixed convection regime, the effects of which are noticeable as heat transfer enhancement or degradation. It is found that CO2 outperforms helium under identical natural circulation conditions. Decay heat removal is found to have a quadratic dependence on pressure in the laminar flow regime and linear dependence in the turbulent flow regime. Other parametric studies have been performed as well. In conclusion, convection cooling loops are a credible means for GFR decay heat removal and LOCA-COLA is an effective tool for steady state analysis of cooling loops.

Theoretical study on transesterification in a combined process consisting of a reactive distillation column and a pervaporation unit

2011 ◽  
Vol 65 (2) ◽  
Author(s):  
Zuzana Švandová ◽  
Jozef Markoš
Keyword(s):  
Steady State ◽  
Distillation Column ◽  
Reactive Distillation ◽  
Steady States ◽  
Multiple Steady States ◽  
Process Unit ◽  
Steady State Analysis ◽  
Operation Temperature ◽  
State Behaviour ◽  
State Analysis

AbstractSteady state analysis of a combined hybrid process consisting of a reactive distillation column, pervaporation unit, and a distillation column is presented. This process configuration was first presented by Steinigeweg and Gmehling (2004) for the transesterification of methyl acetate and butanol to butyl acetate and methanol. This system is characteristic for its low reaction rate and complex phase equilibrium. Steinigeweg and Gmehling (2004) have shown that the combination of reactive distillation and pervaporation is favourable since conversions close to 100 % can be reached with a reasonable size of the reactive section in the reactive distillation column. The aim of this paper is to show that although high conversion can be achieved, very complicated steady state behaviour must be expected. The presented analysis is based on mathematical modelling of a process unit, where the steady-state analysis, including continuation and bifurcation analyses, was used. Multiple steady states were predicted for the studied system; three steady states with conversions higher than 98 %. However, not all predicted steady states met the maximal allowed temperature condition in the reactive section (catalyst maximal operation temperature of 393 K). The presence of multiple steady states reduces the operability and controllability of the reactive distillation column during its start-up and during the occurrence of any variation of operating parameters because the system can be shifted from one steady state to another one (concurrent exceeding the maximal allowed temperature) with unwanted consequences, e.g. production loss. Therefore, design and subsequent operation of such a complicated system is an ambitious task requiring knowledge of any possible system behaviour.

scholarly journals FRAP-S2: a computer code for the steady state analysis of oxide fuel rods

1977 ◽  
Author(s):  
J. A. Dearien ◽  
M. P. Bohn ◽  
G. A. Berna ◽  
D. R. Coleman ◽  
E. T. Laats
Keyword(s):  
Steady State ◽  
Computer Code ◽  
Oxide Fuel ◽  
Fuel Rods ◽  
Steady State Analysis ◽  
State Analysis

Numerical Prediction of Efficiency, Cavitation and Unsteady Phenomena in Water Turbines

2008 ◽  
Author(s):  
Dragica Josˇt ◽  
Andrej Lipej ◽  
Peter Mezˇnar
Keyword(s):  
Steady State ◽  
Numerical Analysis ◽  
Detailed Analysis ◽  
Computer Code ◽  
Second Step ◽  
Piping System ◽  
Steady State Analysis ◽  
Pelton Turbine ◽  
Ansys Cfx ◽  
Water Turbines

The paper presents numerical analysis of the flow in all types of water turbines. Analysis was performed by ANSYS CFX-11.0 computer code. A detailed analysis of complete radial and axial turbine is presented. On the basis of numerical results efficiency and cavitation are predicted and compared to the measured results obtained on test rigs in Turboinstitut. The paper presents also numerical analysis of the flow in a two jet Pelton turbine. The analysis was divided into two parts. At first a steady state analysis of the flow in the piping system with the jets at the outlet was performed. The second step was unsteady analysis of the runner with jets. The casing was not included in the domain of calculation. The predicted efficiency is compared to the measured values.

scholarly journals FRAPCON-1: a computer code for the steady state analysis of oxide fuel rods

1978 ◽  
Author(s):  
G. A. Berna ◽  
M. P. Bohn ◽  
D. R. Coleman ◽  
D. D. Lanning
Keyword(s):  
Steady State ◽  
Computer Code ◽  
Oxide Fuel ◽  
Fuel Rods ◽  
Steady State Analysis ◽  
State Analysis
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