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... i 521 Sixth Edition & Seventh Edi]]></title>
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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>Thu, 16 May 2024 14:26:29 +0000</pubDate> <ttl>180</ttl> <item> <title>Requirement Of Buffer Vessel Upstream On Reciprocating Compressor.</title> <link>https://www.cheresources.com/invision/topic/32051-requirement-of-buffer-vessel-upstream-on-reciprocating-compressor/</link> <description>I am working in Green Hydrogen sector. Wanted to learn requirement of Buffer vessel upstream of Reciprocating compressor if we are generating H2 at 8 barg from Electroylzer. If not like conventional oil ang gas knock out drum is sufficient.</description> <pubDate>Thu, 16 May 2024 14:26:29 +0000</pubDate> <guid isPermaLink="false">https://www.cheresources.com/invision/topic/32051-requirement-of-buffer-vessel-upstream-on-reciprocating-compressor/</guid> </item> <item> <title>Chemical Injection Point</title> <link>https://www.cheresources.com/invision/topic/32046-chemical-injection-point/</link> <description><![CDATA[Hi, <br><br>As per shell dep, chemical injection points shall have a non return valve upstream the block valve to avoid utility contamination, in case I have a two diaphragm pumps each dosing pump has it's own check valve and the distance from the injection point is 12m, can I delete the check valve at injection point ? Do you see that it's necessary to have the check valve at injection point, Until now I never saw a chemical injection point without a check valve, and I'm confused. <br><br>Thank you]]></description> <pubDate>Wed, 15 May 2024 05:12:39 +0000</pubDate> <guid isPermaLink="false">https://www.cheresources.com/invision/topic/32046-chemical-injection-point/</guid> </item> <item> <title>In Letters And Manuscripts</title> <link>https://www.cheresources.com/invision/topic/32045-in-letters-and-manuscripts/</link> <description>Europe, and in Ancient Russia</description> <pubDate>Tue, 14 May 2024 18:10:35 +0000</pubDate> <guid isPermaLink="false">https://www.cheresources.com/invision/topic/32045-in-letters-and-manuscripts/</guid> </item> <item> <title><![CDATA[What Is The Difference Between Api 521 Sixth Edition & Seventh Edi]]></title> <link>https://www.cheresources.com/invision/topic/32043-what-is-the-difference-between-api-521-sixth-edition-seventh-edition/</link> <description><![CDATA[<p>Dear Members,</p><p> </p><p>Does anybody know what are the changes API has made between its Sixth & Seventh Edition of API 521,</p><p> </p><p>In general does API specify anywhere what changes are made in the latest editions as compared to the previous ones.</p><p> </p><p>Thanks</p><p>Best Regards</p>]]></description> <pubDate>Mon, 13 May 2024 07:23:59 +0000</pubDate> <guid isPermaLink="false">https://www.cheresources.com/invision/topic/32043-what-is-the-difference-between-api-521-sixth-edition-seventh-edition/</guid> </item> <item> <title>Negative Resistance Coeffecient For Tees</title> <link>https://www.cheresources.com/invision/topic/32042-negative-resistance-coeffecient-for-tees/</link> <description><![CDATA[Hello everyone,<br><br>I was reading somewhere that the K value (resistance coeffecient) for tees can be negative. What is the reasin for that?]]></description> <pubDate>Sat, 11 May 2024 05:10:06 +0000</pubDate> <guid isPermaLink="false">https://www.cheresources.com/invision/topic/32042-negative-resistance-coeffecient-for-tees/</guid> </item> <item> <title>Maximum Natural Gas Flow Through Orifice</title> <link>https://www.cheresources.com/invision/topic/32041-maximum-natural-gas-flow-through-orifice/</link> <description><![CDATA[<p>Hello everyone,</p><p> </p><p>I would like to answer the question of what the maximum volumetric flow of natural gas is theoretically possible given the conditions. For some context, a control valve on a natural gas feed line was upsized with the assumption that the valve was the constraint of flow in the system. After the valve was replaced to one of larger size, the maximum flow has shown to be less than before on a smaller control valve. The new valve design included an orifice plate downstream of the valve which is the suspected restriction. </p><p> </p><p>To simplify the problem at hand, I would like to calculate the maximum flow possible on the outlet side while completely ignoring this upsized valve and orifice plate. This would rule out that the valve is the restraint and hopefully provide some understanding of the limits of the system.</p><p> </p><p>The feed natural gas line is a six-inch pipe that distributes the flow to 18 one-inch diameter holes. Initially, I attempted to model this scenario as a nozzle in SolidWorks, where the inlet is the six-inch diameter feed at 165 psig, 70F that converges to an outlet with the sum of cross sectional area of the 18 outlet holes. The outlet condition was that the environmental/surrounding pressure is 35 psig. The simulation did not run- stating that the velocity of flow was supersonic. This in turn led me to believe that the problem could be answered by assuming compressible fluid choked flow. I used a Purdue question as a resource (<a href='https://engineering.purdue.edu/~wassgren/teaching/ME30800/NotesAndReading/CompressibleFlow_ConvergingNozzle_Reading.pdf' class='bbc_url' title='' rel='nofollow'>https://engineering.purdue.edu/~wassgren/teaching/ME30800/NotesAndReading/CompressibleFlow_ConvergingNozzle_Reading.pdf</a>), but the mass flow of the natural gas was 560.4 kg/min which then converted to 32,980 cf/min. This flow is high and I am not sure if my calculation is correct. The goal is to answer if 20,000 cf/min of natural gas is possible to be discharged on the outlet side. In this problem- I am excluding any major and minor losses, just to be able to answer what is the maximum discharge flow of NG out of these 18 holes, and does it exceed 20,000 cf/min. </p><p> </p><p>I hope that sheds some light on this case. I will clarify what I can if I missed parts. Please guide me on what tools to use to answer this problem.</p><p> </p><p>Thank you!</p><p> </p><p>Sincerely,</p><p>ukrche</p><p> </p>]]></description> <pubDate>Fri, 10 May 2024 13:33:27 +0000</pubDate> <guid isPermaLink="false">https://www.cheresources.com/invision/topic/32041-maximum-natural-gas-flow-through-orifice/</guid> </item> <item> <title>Dp Drop In Structured Packing Amine Absorber Causing Issues</title> <link>https://www.cheresources.com/invision/topic/32040-dp-drop-in-structured-packing-amine-absorber-causing-issues/</link> <description><![CDATA[<p>Got 2x aMDEA absorption column's with structured packing removing CO2 receiving exactly the same feed gas. Always have problems with one of the absorbers while the other one never has an issue. Occasionally the dP (based on dP instrument for each bed not individual PTs) across the packing of both the top and bottom bed plummets (reduces by 25-50%) on the troublesome absorber, with no change in gas or amine flow. We then go offspec and have to reduce gas rates by about 20%. Sometime later the dP will recover back to normal and the rates can be increased again. The only other symptom, that is repeatable, is that the temperature on the lean amine inlet and the gas outlet of the absorber inverts when these events occur. Normally the gas outlet temp is cooler than the the lean amine inlet temp (of course there could be minor calibration issues). However when the issue occurs this inverts slightly (gas outlet becomes warmer than lean inlet). It seems to be completely random when these "dP" events occur however we have repeated it by taking off our carbon bed and filtration on the lean amine side for 7 days and we had issues until we brought back the carbon bed a few weeks later after finishing maintenance. </p><p> </p><p>The regeneration system is completely fine (regen temperature is constant) and there is no change in valve opening , levels suggesting there is significant foaming. The quality of the amine (activator, HSS , strength , lean loading, degradation etc) is the same in each unit and the amine is completely clear (like water) when sampled. Use of antifoam (silicon based antifoam) is also the same along with the use of activated carbon and filters (5um filters U/S & D/S of carbon bed slipstream). The troublesome column has been inspected and was literally spotless.</p><p> </p><p>To me the only way the dP can change across the structured packing, at constant gas and liquid flow, is due to a change in density or viscosity of the gas / liquid inside the column. Impact on gas viscosity would be minimal so you would suggest the liquid phase. This would usually suggest the column is foaming or potentially flooding however you would expect the dP to rise in those scenarios hence the confusion. </p>]]></description> <pubDate>Fri, 10 May 2024 07:33:12 +0000</pubDate> <guid isPermaLink="false">https://www.cheresources.com/invision/topic/32040-dp-drop-in-structured-packing-amine-absorber-causing-issues/</guid> </item> <item> <title>Dimensionamento De Bomba Para Carregamento Na Plataforma</title> <link>https://www.cheresources.com/invision/topic/32039-dimensionamento-de-bomba-para-carregamento-na-plataforma/</link> <description><![CDATA[<p>Estou avaliando um projeto de dimensionamento de uma bomba para carregamento simultâneo de 8 carretas.. como avaliar se a vazão apresentada é adequada? Que variáveis preciso considerar? </p><p> </p><p>Desde já, agradeço a ajuda!</p>]]></description> <pubDate>Fri, 10 May 2024 02:13:21 +0000</pubDate> <guid isPermaLink="false">https://www.cheresources.com/invision/topic/32039-dimensionamento-de-bomba-para-carregamento-na-plataforma/</guid> </item> <item> <title>Buffer Tank Sizing Upstream Screw Compressor</title> <link>https://www.cheresources.com/invision/topic/32038-buffer-tank-sizing-upstream-screw-compressor/</link> <description><![CDATA[<p>Hello Everyone</p><p> </p><p>I'd like to discuss a challenge we've encountered during testing of our installed compressor and seek your input on potential solutions.</p><p> </p><p>Our setup involves a screw compressor tasked with compressing CO2 from approximately 0.2 barg to 23 barg continuously. A Pressure Transmitter (PT) is installed at the compressor inlet to regulate both the compressor speed and the opening of a recycling valve in response to inlet pressure, thus controlling the gas flow output. Notably, the compressor is designed to trip at high-pressure (PHH) 450 mbarg and low-pressure (PLL) -100 mbarg.</p><p> </p><p>Upstream from the compressor, we receive a variable CO2 feed continiously from an epuration station, resulting in monthly/daily supply curves resembling a sawtooth pattern. During startup, the screw compressor struggles to keep pace with the rapid fluctuations in the CO2 feed, leading to shutdowns.</p><p> </p><p>To address this issue, we are considering the addition of a buffer tank upstream of the compressor to mitigate the variability in the CO2 feed. The aim is to maintain a consistent CO2 flow, such as 40 Nm3/h, within a pressure range of 150 mbarg to 350 mbarg.</p><p> </p><p>This buffer tank would need to be replenished by the CO2 feed from the epuration station.</p><p> </p><p>We welcome your suggestions on resolving this situation. Additionally, we seek guidance on sizing the buffer tank. Should we also consider installing a booster compressor upstream of the buffer tank for filling operations? If so, would any compressor be capable of handling the rapid fluctuations in the CO2 feed?</p><p style="color:rgb(13,13,13);font-family:'Söhne', 'ui-sans-serif', 'system-ui', '-apple-system', 'Segoe UI', Roboto, Ubuntu, Cantarell, 'Noto Sans', sans-serif, 'Helvetica Neue', Arial, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol', 'Noto Color Emoji';font-size:16px;"> </p><p>Many thanks</p>]]></description> <pubDate>Thu, 09 May 2024 16:51:07 +0000</pubDate> <guid isPermaLink="false">https://www.cheresources.com/invision/topic/32038-buffer-tank-sizing-upstream-screw-compressor/</guid> </item> <item> <title>Age Impact On Pipe Roughness</title> <link>https://www.cheresources.com/invision/topic/32037-age-impact-on-pipe-roughness/</link> <description><![CDATA[<p><span> </span></p><p><span style="font-family:'comic sans ms', cursive;"><span style="font-size:14px"><span><span> </span>Dear all,</span></span></span></p><p><span style="font-family:'comic sans ms', cursive;"><span style="font-size:14px"><span>I hope you all are doing well in your lives. I'm</span><span> a junior process engineer </span><span>and </span><span>currently</span><span> working on an assignment relevant to pump evaluation for a different service than initially purchased</span><span>. </span><span>One</span><span> of the confusion I have </span><span>come across</span><span> during my calculations is regarding the pipe roughness </span><span>of the pipe</span><span>. </span><span>Normally</span><span> </span><span>0.0018</span><span>" is considered for a new steel pipe </span><span>but</span><span> how </span><span>to</span><span> </span><span>find out</span><span> the impact of age on this figure </span><span>theoretically? Kindly share if there is any standard practice or your experience to address this query. </span></span></span></p><p> </p><p><span style="font-family:'comic sans ms', cursive;"><span style="font-size:14px"><span>Background </span></span></span></p><ol> <li><span style="font-family:'comic sans ms', cursive;"><span style="font-size:14px"><span>Pipe material - CS</span></span></span></li> <li><span style="font-family:'comic sans ms', cursive;"><span style="font-size:14px"><span>Time elapsed since in use - 15 to 20 years </span></span></span></li> <li><span style="font-family:'comic sans ms', cursive;"><span style="font-size:14px"><span>The pipeline is a piggable multi-product dispatch line (Gasoline, Kerosene and Diesel)</span></span></span></li> <li><span style="font-family:'comic sans ms', cursive;"><span style="font-size:14px"><span>Line size and length - 6" & 650 m</span></span></span></li></ol><p>@Art Montemayor @Bobby Strain @breizh @fallah @latexman</p><p> </p><p><span style="font-family:'comic sans ms', cursive;"><span style="font-size:14px"><span>Thank you, looking forward to your kind responses.</span></span></span></p><p><span> </span><span> </span></p><p> </p>]]></description> <pubDate>Thu, 09 May 2024 09:24:51 +0000</pubDate> <guid isPermaLink="false">https://www.cheresources.com/invision/topic/32037-age-impact-on-pipe-roughness/</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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