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<description><![CDATA[<div style="color:rgb(0,0,0);font-family:'-apple-sy ...
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<?xml version="1.0" encoding="UTF-8" ?><rss version="2.0"><channel> <title>front_page</title> <description>Front page of site</description> <link>https://www.cheresources.com/invision</link> <pubDate>Fri, 20 Dec 2024 14:00:06 +0000</pubDate> <ttl>180</ttl> <item> <title>Subcooled Reflux And Energy Usage</title> <link>https://www.cheresources.com/invision/topic/32296-subcooled-reflux-and-energy-usage/</link> <description><![CDATA[<p>Hi,</p><p> </p><p>I'm a young engineer currently working on some optimisation of destillation columns in the recovery section of a polymer plant. These columns work on atmospheric pressure and have a high reflux ratio (not internal reflux ratio) RR=3. Our top temperature is 80°C but we have a condensor and this cools the reflux all the way to 30°C (90/10 ethanol water mixture). This low temperature of reflux creates a good amount of internal reflux. However I once read in a book that having very subcooled reflux decreases the efficiency of the trays below, because the vapour and liquid cannot reach their equilibrium.</p><p>At the moment we have no control on the cooling of our condensors. Could it maybe be beneficial to have temperature control on our condensor so that we only have 10°C of subcooling? Would this make sense energy wise (reboiler load, tray effiencies etc)? Does anyone have some references to this problem? Thank you in advance!</p>]]></description> <pubDate>Fri, 20 Dec 2024 14:00:06 +0000</pubDate> <guid isPermaLink="false">https://www.cheresources.com/invision/topic/32296-subcooled-reflux-and-energy-usage/</guid> </item> <item> <title>Breather Valves - Liquid Movement In Breathing Scenario</title> <link>https://www.cheresources.com/invision/topic/32293-breather-valves-liquid-movement-in-breathing-scenario/</link> <description><![CDATA[<p>Hello everyone,</p><p> </p><p>I am interested in the case of liquid movement scenario. By liquid movement, I mean the continuous flow out of thank, which causes vacuum. Hence in breathing of air is required. </p><p> </p><p> </p><p>I found somewhere that the equation to calculate the amount of in-breathing equivalent air flow is:</p><p> </p><p>Vair = Vliquid,outlet * sqrt(ρair / ρnormal)</p><p> </p><p>where </p><p>Vair is the normal volumetric flowrate of air equivalent for in breathing in Nm3/h</p><p>Vliquid, outlet is the volumetric flowrate of the liquid from the tank in m3/h</p><p>ρair is the density of air at the temperature of air in kg/m3</p><p>ρnormal is the density at normal conditions in kg/m3</p><p> </p><p>My question is how to derive the above equation?</p><p> </p><p> </p><p>(I looked in API 2000, but the formula to calculate the air equivalent is much more complicated.)</p><p> </p><p> </p><p> </p><p> </p><p> </p>]]></description> <pubDate>Sat, 14 Dec 2024 19:00:17 +0000</pubDate> <guid isPermaLink="false">https://www.cheresources.com/invision/topic/32293-breather-valves-liquid-movement-in-breathing-scenario/</guid> </item> <item> <title>Psv Flashing, Sizing Outlet Line 2-Phase.</title> <link>https://www.cheresources.com/invision/topic/32289-psv-flashing-sizing-outlet-line-2-phase/</link> <description><![CDATA[<p style="color:rgb(40,40,40);font-family:helvetica, arial, sans-serif">Hi.</p><p style="color:rgb(40,40,40);font-family:helvetica, arial, sans-serif"> </p><p style="color:rgb(40,40,40);font-family:helvetica, arial, sans-serif">So I am dealing with a 2-phase flashing through the PSV. I am tasked to design or size the outlet piping but one of the leads told me I need to size the vapor and liquid lines at the outlet. Where the outlet line eventually splits into two; separate line for liquid and vapor. I am not sure the approach on this sizing method but can you help shed some light on this? See a depiction of diagram of my system below.<br><br>I am having doubts that vapor and liquid will fully-separate as it passes through the tee designated. Is it really possible since I am trying to contest that we cannot fully-separate the 2-phases at the tee. </p><p style="color:rgb(40,40,40);font-family:helvetica, arial, sans-serif"> </p><div id='attach_wrap' class='clearfix'> <h4>Attached Files</h4> <ul> <li class='attachment'> <a href="https://www.cheresources.com/invision/index.php?app=core&module=attach§ion=attach&attach_id=17301" title="Download attachment"><img src="https://www.cheresources.com/invision/public/style_extra/mime_types/pdf.gif" alt="Attached File" /></a> <a href="https://www.cheresources.com/invision/index.php?app=core&module=attach§ion=attach&attach_id=17301" title="Download attachment"><strong>sketch.pdf</strong></a> <span class='desc'><strong>28.8KB</strong></span> <span class="desc lighter">29 downloads</span> </li> </ul></div>]]></description> <pubDate>Mon, 09 Dec 2024 13:41:49 +0000</pubDate> <guid isPermaLink="false">https://www.cheresources.com/invision/topic/32289-psv-flashing-sizing-outlet-line-2-phase/</guid> </item> <item> <title>Determining Pipeline Design Pressure</title> <link>https://www.cheresources.com/invision/topic/32286-determining-pipeline-design-pressure/</link> <description><![CDATA[<p>Hi all, I'm currently confused about this loop (?) that I face while designing my system. So I'm currently tasked to do a hydraulic simulation of a long transmission pipeline. The service is sales gas. I need to deliver 35 MMSCFD of gas. My feed has 500 psig of max pressure and the destination pressure is 750 psig. I developed two option, compressor station at the upstream and compressor station at the downstream.</p><p> </p><p>I use pipesim as my tools to do the hydraulic simulation. To use pipesim, you first need to chose the schedule (wall thickness) of your pipeline to do the simulation and after that you'll get the backpresure. After getting the backpressure, i then can know the op. system of the pipeline and use it as a base to determine my design pressure that will be used for determining the wall thickness. And once i get the wall thickness, i have to re-do the simulation with the new calculated wall thickness, and the backpressure will change too. So it kinda keep me in the loop. I really dont know how to explain this better but im so confused how do i determine the design pressure of a pipeline without getting stuck in a loop like this? Should i just fully rate my pipeline? But then my wall thickness will be too thick and the pressure drop of the pipeline will be bigger too. I read in NORSOK that you can determine the design pressure of compressor using the shut in pressure by adding the maximum suction pressure with 1.3 times the differential pressure and since my system has a compressor too maybe i can use this as a base, but this will lead me in the same loop too.<br><br><br>P.s. as per my last post someone said "my question was not appropriate to be put in this topic and i should move to students forum." guys idk how to tell this i really am a process engineer in a small engineering company and im new. i wish i could ask my supervisor or anyone with more experiences than me but i cant we're all too occupied with our own project. im handling this project alone and i shouldnt be but i dont have any choice.</p>]]></description> <pubDate>Thu, 05 Dec 2024 13:35:36 +0000</pubDate> <guid isPermaLink="false">https://www.cheresources.com/invision/topic/32286-determining-pipeline-design-pressure/</guid> </item> <item> <title>Slope Of Flare Sub Headers / Tail Pipes And Main Headers</title> <link>https://www.cheresources.com/invision/topic/32284-slope-of-flare-sub-headers-tail-pipes-and-main-headers/</link> <description><![CDATA[<p><span style="color:rgb(0,0,0);font-family:'Segoe UI', 'Helvetica Neue', Helvetica, Roboto, Oxygen, Ubuntu, Cantarell, 'Fira Sans', 'Droid Sans', sans-serif;font-size:15px;">Hi All,</span><br><br><span style="color:rgb(0,0,0);font-family:'Segoe UI', 'Helvetica Neue', Helvetica, Roboto, Oxygen, Ubuntu, Cantarell, 'Fira Sans', 'Droid Sans', sans-serif;font-size:15px;">I am seeking your technical views on the recommended slope of flare subheaders in onshore and offshore facilities. In order to ensure adequate drainage, the slope typically is 1:200 by some engineering guidelines. Flare main headers typically are designed for slope 1:500</span><br><span style="color:rgb(0,0,0);font-family:'Segoe UI', 'Helvetica Neue', Helvetica, Roboto, Oxygen, Ubuntu, Cantarell, 'Fira Sans', 'Droid Sans', sans-serif;font-size:15px;">In view that subheaders are relatively shorter than main flare header, do you agree that at least 1:200 to 1-400 is needed to ensure adequate drainage. Have you experienced potential optimization of flare subheaders and tail pipes slope of 1:500. API 521 7th edition did not distinguish the slope of main headers and subheaders when stating :''</span><br><span style="color:rgb(0,0,0);font-family:'Segoe UI', 'Helvetica Neue', Helvetica, Roboto, Oxygen, Ubuntu, Cantarell, 'Fira Sans', 'Droid Sans', sans-serif;font-size:15px;">A slope of 21 mm in 10 m (1/4 in. in 10 ft) is suggested for all laterals and headers, taking into account piping deflections between supports.''</span><br><br><span style="color:rgb(0,0,0);font-family:'Segoe UI', 'Helvetica Neue', Helvetica, Roboto, Oxygen, Ubuntu, Cantarell, 'Fira Sans', 'Droid Sans', sans-serif;font-size:15px;">Thanks</span><br><br><span style="color:rgb(0,0,0);font-family:'Segoe UI', 'Helvetica Neue', Helvetica, Roboto, Oxygen, Ubuntu, Cantarell, 'Fira Sans', 'Droid Sans', sans-serif;font-size:15px;">Regards,</span></p>]]></description> <pubDate>Mon, 02 Dec 2024 08:45:47 +0000</pubDate> <guid isPermaLink="false">https://www.cheresources.com/invision/topic/32284-slope-of-flare-sub-headers-tail-pipes-and-main-headers/</guid> </item> <item> <title>Opportunities For Heat Recovery In A Chemical Process Plant</title> <link>https://www.cheresources.com/invision/topic/32281-opportunities-for-heat-recovery-in-a-chemical-process-plant/</link> <description><![CDATA[<p>Heat recovery is a key focus of chemical plants nowadays. When executed well, heat recovery projects can increase the plant's energy efficiency and reduce the plant's emissions. I was looking at the use of cooling water in some of our overhead condensers. Using cooling water to cool the overhead vapours effectively wastes the heat from those vapours. If we could, for example, integrate the overhead condenser with a heat pump to preheat reactor/column feed, then the heat from the condensation can be better utilised. Is this a sensible idea? </p><p> </p><p>I am also looking for more ideas on heat recovery and heat integration in a process plant. I think at this point, many of the easy-to-see, low-hanging fruits have already been considered and implemented if they are feasible. There is a need to think of slightly more unconventional ideas or to implement new technology. Thank you!</p>]]></description> <pubDate>Sat, 30 Nov 2024 01:06:27 +0000</pubDate> <guid isPermaLink="false">https://www.cheresources.com/invision/topic/32281-opportunities-for-heat-recovery-in-a-chemical-process-plant/</guid> </item> <item> <title>Purging Blowdown System</title> <link>https://www.cheresources.com/invision/topic/32279-purging-blowdown-system/</link> <description><![CDATA[<p>Hello everyone, </p><p>I have a topic regarding the blowdown system, </p><p>In this system, the blowdown KO Drum discharge to atmosphere and not to flare. I have considered a nitrogen purging in order to prevent oxygen ingress and the possibility of detonation within vent system.</p><p> </p><div>The team is divided, however, as other process engineers suggest avoiding the use of nitrogen and designing the whole system to a design pressure of 40 barg. </div><div>They argue that a pipe designed for a static load of 40 bar can withstand a much higher dynamic pressure.</div><div>This pressure seems very high to me and I would like to have a reference before designing a system with such a high pressure.</div><div>Also, as far as I know, a design pressure of 7 barg should be considered for systems of this type if no notrogen is available.</div><div>Does anyone have a reference on this?</div><div> </div><div>Regards</div><p> </p><p> </p><p> </p><p> </p>]]></description> <pubDate>Fri, 29 Nov 2024 10:45:04 +0000</pubDate> <guid isPermaLink="false">https://www.cheresources.com/invision/topic/32279-purging-blowdown-system/</guid> </item> <item> <title>Secondary Heating Loop For Reactor</title> <link>https://www.cheresources.com/invision/topic/32278-secondary-heating-loop-for-reactor/</link> <description><![CDATA[<p>Hi,</p><p>I’m looking into installing a secondary heating/cooling loop for a glass-lined reactor and was wondering if anyone could share best practices or standard design documents for these systems.</p><p>For example, I’ve noticed that some oil-based systems (e.g DowthermJ) use magnetic pumps and plate-and-shell heat exchangers, while water/glycol systems typically use gasketed plate heat exchangers and pumps with single mechanical seals.</p><p>Is there a specific reason for this design philosophy, or is it mainly due to the fact that DowthermJ can be used at higher temperatures, thus requiring a more robust, high-containment design?</p><p> </p><p>Any insight or general guidance/thoughts is much appreciated. </p>]]></description> <pubDate>Thu, 28 Nov 2024 22:24:59 +0000</pubDate> <guid isPermaLink="false">https://www.cheresources.com/invision/topic/32278-secondary-heating-loop-for-reactor/</guid> </item> <item> <title>Esdv Closure</title> <link>https://www.cheresources.com/invision/topic/32277-esdv-closure/</link> <description><![CDATA[<p>hi all,</p><p>Recently I had come across a facility having ESDV(Emergency shutdown valve) with 2 step closure to avoid water hammer effect. Is it allowable ESDV to have 2 step closure arrangement?</p><p>regards</p><p>stu</p>]]></description> <pubDate>Wed, 27 Nov 2024 14:22:07 +0000</pubDate> <guid isPermaLink="false">https://www.cheresources.com/invision/topic/32277-esdv-closure/</guid> </item> <item> <title>Activated Carbon Selection</title> <link>https://www.cheresources.com/invision/topic/32274-activated-carbon-selection/</link> <description><![CDATA[<div style="color:rgb(0,0,0);font-family:'-apple-system', BlinkMacSystemFont, 'Helvetica Neue', 'Segoe UI', Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol';font-size:13px;">Greetings All,</div><div style="color:rgb(0,0,0);font-family:'-apple-system', BlinkMacSystemFont, 'Helvetica Neue', 'Segoe UI', Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol';font-size:13px;"> </div><div style="color:rgb(0,0,0);font-family:'-apple-system', BlinkMacSystemFont, 'Helvetica Neue', 'Segoe UI', Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol';font-size:13px;">We want to know about the working tendency of our activated carbon filter on amine sweetening unit in lean amine circuit.</div><div style="color:rgb(0,0,0);font-family:'-apple-system', BlinkMacSystemFont, 'Helvetica Neue', 'Segoe UI', Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol';font-size:13px;"> </div><div style="color:rgb(0,0,0);font-family:'-apple-system', BlinkMacSystemFont, 'Helvetica Neue', 'Segoe UI', Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol';font-size:13px;">As part of a recent process adjustment, we increase the flow rate from 25 m³/hr to 30 m³/hr to meet current operational requirements. In this case, we would like to inquire about several key specifications or charts related to the granular size of the activated carbon, including:</div><div style="color:rgb(0,0,0);font-family:'-apple-system', BlinkMacSystemFont, 'Helvetica Neue', 'Segoe UI', Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol';font-size:13px;"><ul><li>Recommended GPM/ft² values</li><li>Bed volume, length and diameter</li><li>Pressure drop considerations when passing lean amine</li></ul></div><div style="color:rgb(0,0,0);font-family:'-apple-system', BlinkMacSystemFont, 'Helvetica Neue', 'Segoe UI', Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol';font-size:13px;"> </div><div style="color:rgb(0,0,0);font-family:'-apple-system', BlinkMacSystemFont, 'Helvetica Neue', 'Segoe UI', Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol';font-size:13px;">Another option we considering the replacement of a carbon filter with cartridge filters, it is essential to carefully evaluate the selection criteria and determine the appropriate number of cartridges, along with key operational parameters </div><div style="color:rgb(0,0,0);font-family:'-apple-system', BlinkMacSystemFont, 'Helvetica Neue', 'Segoe UI', Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol';font-size:13px;"> </div><ul><li>Recommended GPM/ft² values</li><li>filter volume, length and diameter</li><li>Pressure drop considerations when passing lean amine</li></ul><div style="color:rgb(0,0,0);font-family:'-apple-system', BlinkMacSystemFont, 'Helvetica Neue', 'Segoe UI', Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol';font-size:13px;">I am looking forward to your response.</div><div style="color:rgb(0,0,0);font-family:'-apple-system', BlinkMacSystemFont, 'Helvetica Neue', 'Segoe UI', Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol';font-size:13px;"> </div><div style="color:rgb(0,0,0);font-family:'-apple-system', BlinkMacSystemFont, 'Helvetica Neue', 'Segoe UI', Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol';font-size:13px;">Regards,</div>]]></description> <pubDate>Mon, 25 Nov 2024 05:30:53 +0000</pubDate> <guid isPermaLink="false">https://www.cheresources.com/invision/topic/32274-activated-carbon-selection/</guid> </item></channel></rss>If you would like to create a banner that links to this page (i.e. this validation result), do the following:
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