Sunday, August 26, 2007
This question has been raised by many engineers and debated in many discussion.
Careful review on the relief valve structure, process fluid passing through a nozzle instead of an orifice. Those many researchers such as Dr. Ron Darby for multiphase flow in Direct Integration method (HDI), Dr Fauske & Dr Henry for two phase relief in Homogeneous Non-equilibrium model (HNE), Dr. Joseph Leung for two phase flow in Omega method, etc have modelled a relief valve as a nozzle.
Classical and conventional studies informed us that vena contracta (VC) will only occur in sharp edge orifice. However, the flow restricting area in a relief valve as decribed by many well knowed specialists is not an orifice, but is actually a nozzle. Thus there is NO vena contracta downstream of the nozzle.
Phenomenon of flow through a nozzle in relief valve is extremely fast. Choked flow is possible occur in some location "A" in the nozzle instead of outside the nozzle (may be closed to the exit end), from the inlet to "A" will be a REVERSIBLE process which generally accepted by most of the specialists. Thus, it is ISENTROPIC process. From location "A" to PSV outlet, the system is expanded and change in state. It will be slow down. There will be transformation energy loss however the enthalpy is maintain constant (ISENTHALPIC). This process is IRREVERSIBLE. "A" is viewed as vena contracta in the relief valve's nozzle. Those in sizing a relief valve, we ignore the frictional loss in the nozzle and consider ISENTROPIC process. However, from expansion process via safety valve (Vena contracta to relief outlet), the process will be ISENTHALPIC.
Related topics
If you benefits from this post, buy me some sweets
Labels: Modelling, Pressure Relief Device, PSV, Thermodynamic
Saturday, May 26, 2007
Following earlier introduction to <<Optimized Gas Treating, Inc. (OGT) - Experts in CO2-Amine>>, there are some others FREE articles available on this site for download...Refer to below listing and relevant links...ENJOY...
By the way, if you know some good site related to Chemical & Process Engineering, (as you know, i am focusing on distillation recently) do recommend to me...i will crawl the website thoroughly...and let inform our lovely Chemical & Process Engineers...
Knowledge does not belongs to any of us but it belongs to ALL of US...Let Share It...I still believe the more you share, the more you will gain...
Related Post- ProMax from BR&E - Renowed Process Simulator in Gas Treating Industry
- Optimized Gas Treating, Inc. (OGT) - Experts in CO2-Amine
- Air Pollution Control & Tail Gas Treatment
Labels: Absorption, Air Pollution Control, Amine, Column, Design, Distillation, Global warming, Modelling, Packed Column, Packing, Process simulation, Tail Gas Treatment, Technology, Tower internals
Friday, May 25, 2007
Carbon Dioxide (CO2) is known as one of industrial waste gas causing global warming...there are number of measures are implemented to reduce global warming. CO2 reduction measures are CO2 capturing, reinjection into aquifer, injection into reservior for well maintenance, gas injection for enhanced oil recovery (EOR), etc.
Above efforts will reduce CO2 release into atmosphere. However, recycling CO2 will increase quantity of CO2 in oil and result serious corrosion problem. Hence it needs to be removed from the flashed gas (from unstabilised oil). CO2 removal technology using amine absorption has been used for many years. Recently i found a website (OGT) where the founders, Ralph Weiland and Jack Dingman are those experts in this technology.
Optimized Gas Treating, Inc. (OGT) was established in 1992 by Ralph Weiland and Jack Dingman for the single purpose of providing a commercial version of a Windows-based software package for simulating acid gas removal with aqueous alkanolamines that uses a fundamental mass and heat transfer rate approach to column modeling. ProTreat™ is the culmination of more than 30 years of research in gas treating supported by government and industry in both academic and commercial environments. ProTreat is our sole product. Consequently, it receives our undivided attention in maintaining and enhancing its capabilities so that it remains the premier software package for gas treating with amines. OGT’s principals are recognized world experts in most aspects of gas treating — they offer a total of nearly 60 years of relevant experience.
Some FREE articles offered by OGT :
Column related
WebWorm
Labels: Absorption, Amine, Column, Distillation, Equilibrium, Extraction, Global warming, Modelling, Packed Column, Packing, Process simulation, Software, Technology, Tower internals
Friday, April 27, 2007
Today found an interesting website for Process & Chemical Engineer, especially those involve in Design and Engineering...VMG
Virtual Materials Group (VMG), a process simulation and material behavior prediction software...client from oil, chemical and refinery technology companies.
VMGSim™ - VMG product...process simulation system integrates flowsheeting kernel with Visio™ for ease-of-use and graphics interface and Excel™ for seamless bidirectional spreadsheet calculations. (Download)
FREE Articles available in this site...
CAPE-OPEN Specialty Property Packages - New Thermodynamic Models and Software Integration Paradigm A. Satyro, Yau-Kun Li, Rajeev K. Agarwal and Oscar J. Santollani,
"Modeling Urea Processes: A New Thermodynamic Model and Software Integration Paradigm", Presented at the 2000 Clearwater Convention on Phosphate Fertilizer & Sulfuric Acid Technology Sheraton Sand Key Resort, Clearwater Beach, Florida -- June 16-18, 2000
Others FREE articles may request using this LINK
TZValve 3.0.2, a distillation software developed by The Distillation Group is marketed by VMG...I found The Distillation Group website, will expedite this site and share my findings in post...
WebWorm
Labels: Distillation, Modelling, Process simulation, Thermodynamic
