<body><script type="text/javascript"> function setAttributeOnload(object, attribute, val) { if(window.addEventListener) { window.addEventListener('load', function(){ object[attribute] = val; }, false); } else { window.attachEvent('onload', function(){ object[attribute] = val; }); } } </script> <div id="navbar-iframe-container"></div> <script type="text/javascript" src="https://apis.google.com/js/platform.js"></script> <script type="text/javascript"> gapi.load("gapi.iframes:gapi.iframes.style.bubble", function() { if (gapi.iframes && gapi.iframes.getContext) { gapi.iframes.getContext().openChild({ url: 'https://www.blogger.com/navbar.g?targetBlogID\x3d8968604820003269863\x26blogName\x3dChemical+%26+Process+Technology\x26publishMode\x3dPUBLISH_MODE_BLOGSPOT\x26navbarType\x3dBLUE\x26layoutType\x3dCLASSIC\x26searchRoot\x3dhttps://webwormcpt.blogspot.com/search\x26blogLocale\x3den\x26v\x3d2\x26homepageUrl\x3dhttp://webwormcpt.blogspot.com/\x26vt\x3d6505904876529004088', where: document.getElementById("navbar-iframe-container"), id: "navbar-iframe", messageHandlersFilter: gapi.iframes.CROSS_ORIGIN_IFRAMES_FILTER, messageHandlers: { 'blogger-ping': function() {} } }); } }); </script>

Chemical Process Technology

Continue to learn tips, knowledge and experience about Chemical Process Technology...

Enter your email address:


CLOSE WINDOW


 

Chemical & Process Technology

A place to share knowledge, lesson learnt...

Tuesday, May 5, 2009

Display problem ? Click HERE

Recommended :
Subscribe FREE - Processing Magazine

Previous post "Several Criteria and Constraints for Flare Network - Process" has discussed several major important criteria and constraints related flare system. In particular, back pressure is critical to performance of pressure relief valve (PRV) from capacity and stability aspect. Back pressure at PRV is typically back calculated from flare tip, main header, sub-header and finally tail pipe. Isothermal equation may be used for flare pipe pressure drop calculation for conservatism.

AFSA or FLARENET is commonly used for flare network modeling. In calculating back pressure at the PRV, flare tip pressure drop is required. In some flare system, i.e. Refinery flare system, a water seal is provided at the bottom of stack to minimum air ingress into main flare system. This water seal (subject to design) may induce a rather fix pressure drop to the back pressure estimation, in particular to very low pressure system i.e. sour gas flare.

How shall engineer create a constant pressure drop in AFSA / FLARENET model ?

One of the way is to use the "Flow Bleed" component. "Flow Bleed" is normally use for fix flow splitter with a fix pressure drop. In this case, introduce a "Flow Bleed" component with following setting

  • Offtake Multiplier set to zero (0)
  • Offtake Offset set to zero (0)
  • Pressure drop set to intended pressure drop



Above image shown the use of "Flow Bleed" as fix pressure drop device. A fix pressure drop of 0.1 bar has been introduced in the flare network.

Related Topic

Labels: ,

posted by Webworm, 11:06 PM

0 Comments:

Post a Comment

Let us know your opinion !!! You can use some HTML tags, such as  <b>, <i>, <a>

Subscribe to Post Comments [Atom]

Home:

<< Home