{"id":31170,"date":"2026-07-25T10:14:36","date_gmt":"2026-07-25T02:14:36","guid":{"rendered":"https:\/\/shchimay.com\/from-seawater-to-stack-a-field-guide-to-the-green-hydrogen-water-chain-by-shanghai-chimay\/"},"modified":"2026-07-25T10:14:36","modified_gmt":"2026-07-25T02:14:36","slug":"from-seawater-to-stack-a-field-guide-to-the-green-hydrogen-water-chain-by-shanghai-chimay","status":"publish","type":"post","link":"https:\/\/shchimay.com\/fr\/from-seawater-to-stack-a-field-guide-to-the-green-hydrogen-water-chain-by-shanghai-chimay\/","title":{"rendered":"From Seawater to Stack: A Field Guide to the Green Hydrogen Water Chain by Shanghai ChiMay"},"content":{"rendered":"<hr \/>\n<p>title: &ldquo;From Seawater to Stack: A Field Guide to the Green Hydrogen Water Chain by Shanghai ChiMay&rdquo;<br \/>\ndescription: &ldquo;A field-oriented walkthrough of the green hydrogen water chain from seawater intake to electrolyzer stack, with monitoring practices from Shanghai ChiMay.&rdquo;<br \/>\ntype: high-traffic-imitation<br \/>\ntheme: Green Hydrogen &amp; Electrolyzer Feedwater<br \/>\ndate: 2026-07-06<\/p>\n<hr \/>\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_50 counter-hierarchy ez-toc-counter ez-toc-light-blue ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/shchimay.com\/fr\/from-seawater-to-stack-a-field-guide-to-the-green-hydrogen-water-chain-by-shanghai-chimay\/#From_Seawater_to_Stack_A_Field_Guide_to_the_Green_Hydrogen_Water_Chain_by_Shanghai_ChiMay\" title=\"From Seawater to Stack: A Field Guide to the Green Hydrogen Water Chain by Shanghai ChiMay\">From Seawater to Stack: A Field Guide to the Green Hydrogen Water Chain by Shanghai ChiMay<\/a><ul class='ez-toc-list-level-2'><li class='ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/shchimay.com\/fr\/from-seawater-to-stack-a-field-guide-to-the-green-hydrogen-water-chain-by-shanghai-chimay\/#Stage_1_Seawater_Intake\" title=\"Stage 1: Seawater Intake\">Stage 1: Seawater Intake<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/shchimay.com\/fr\/from-seawater-to-stack-a-field-guide-to-the-green-hydrogen-water-chain-by-shanghai-chimay\/#Stage_2_Pretreatment_for_SWRO\" title=\"Stage 2: Pretreatment for SWRO\">Stage 2: Pretreatment for SWRO<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/shchimay.com\/fr\/from-seawater-to-stack-a-field-guide-to-the-green-hydrogen-water-chain-by-shanghai-chimay\/#Stage_3_Seawater_Reverse_Osmosis\" title=\"Stage 3: Seawater Reverse Osmosis\">Stage 3: Seawater Reverse Osmosis<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/shchimay.com\/fr\/from-seawater-to-stack-a-field-guide-to-the-green-hydrogen-water-chain-by-shanghai-chimay\/#Stage_4_Second-Pass_RO_or_Ion_Exchange\" title=\"Stage 4: Second-Pass RO or Ion Exchange\">Stage 4: Second-Pass RO or Ion Exchange<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/shchimay.com\/fr\/from-seawater-to-stack-a-field-guide-to-the-green-hydrogen-water-chain-by-shanghai-chimay\/#Stage_5_Polishing_to_Ultrapure\" title=\"Stage 5: Polishing to Ultrapure\">Stage 5: Polishing to Ultrapure<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/shchimay.com\/fr\/from-seawater-to-stack-a-field-guide-to-the-green-hydrogen-water-chain-by-shanghai-chimay\/#Stage_6_Stack_Feed\" title=\"Stage 6: Stack Feed\">Stage 6: Stack Feed<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/shchimay.com\/fr\/from-seawater-to-stack-a-field-guide-to-the-green-hydrogen-water-chain-by-shanghai-chimay\/#What_the_Full_Chain_Costs\" title=\"What the Full Chain Costs\">What the Full Chain Costs<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/shchimay.com\/fr\/from-seawater-to-stack-a-field-guide-to-the-green-hydrogen-water-chain-by-shanghai-chimay\/#Bringing_It_Together\" title=\"Bringing It Together\">Bringing It Together<\/a><\/li><\/ul><\/li><\/ul><\/nav><\/div>\n<h1 id=\"from-seawater-to-stack-a-field-guide-to-the-green-hydrogen-water-chain-by-shanghai-chimay\"><span class=\"ez-toc-section\" id=\"From_Seawater_to_Stack_A_Field_Guide_to_the_Green_Hydrogen_Water_Chain_by_Shanghai_ChiMay\"><\/span>From Seawater to Stack: A Field Guide to the Green Hydrogen Water Chain by Shanghai ChiMay<span class=\"ez-toc-section-end\"><\/span><\/h1>\n<p>Green hydrogen developers in coastal Australia, the Arabian Gulf, southern Europe, and parts of southern Africa are increasingly building their electrolyzer plants around seawater. Freshwater simply isn&rsquo;t available at the scale that gigawatt hydrogen requires. But going from seawater at 35,000\u201345,000 mg\/L total dissolved solids to electrolyzer feedwater at \u22640.1 \u00b5S\/cm is a demanding water-treatment journey \u2014 the largest single-step purification cascade in industrial water. This field guide walks operators, EPCs, and developers through the full seawater-to-stack chain and shows where Shanghai ChiMay&rsquo;s online instrumentation earns its place at each step.<\/p>\n<h2 id=\"stage-1-seawater-intake\"><span class=\"ez-toc-section\" id=\"Stage_1_Seawater_Intake\"><\/span>Stage 1: Seawater Intake<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>The first challenge is the intake itself. Coastal seawater is highly variable \u2014 temperature, salinity, turbidity, biological load, and dissolved oxygen all shift with tides, weather, and seasons. A typical intake instrumentation package includes:<\/p>\n<ul>\n<li><strong>Salinity sensor<\/strong> for continuous salt content tracking (typically 33\u201345 psu at open ocean intakes)<\/li>\n<li><strong><a href=\"\/tag\/Turbidity-Meter\" target=\"_blank\"><strong><a href=\"\/tag\/turbidity-meter\/\" target=\"_blank\"><strong>turbidity meter<\/strong><\/a><\/strong><\/a><\/strong> to flag storm-driven sediment events<\/li>\n<li><strong>Temperature transmitter<\/strong> because SWRO membrane performance depends heavily on feed temperature<\/li>\n<li><strong>DO meter<\/strong> to characterize the biological activity in the intake<\/li>\n<\/ul>\n<p>Shanghai ChiMay&rsquo;s salinity sensors and turbidity testers are field-hardened for saltwater exposure. Coating and connector selection are the details that determine whether an intake sensor lasts three months or three years.<\/p>\n<h2 id=\"stage-2-pretreatment-for-swro\"><span class=\"ez-toc-section\" id=\"Stage_2_Pretreatment_for_SWRO\"><\/span>Stage 2: Pretreatment for SWRO<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Before seawater can reach the SWRO membranes, it must be filtered and dechlorinated. Instrumentation in this stage focuses on protecting the membrane investment:<\/p>\n<ul>\n<li><strong>Residual chlorine transmitter<\/strong> on the SWRO feed. Chlorine damages polyamide membranes irreversibly; a functioning ORP or free-chlorine measurement is non-negotiable.<\/li>\n<li><strong><a href=\"\/tag\/Turbidity-Meter\" target=\"_blank\"><strong><a href=\"\/tag\/turbidity-meter\/\" target=\"_blank\"><strong>turbidity meter<\/strong><\/a><\/strong><\/a><\/strong> on the ultrafiltration outlet (target \u22640.1 NTU)<\/li>\n<li><strong>Multi-parameter sensor<\/strong> for pH, ORP, temperature tracking on the antiscalant dosing loop<\/li>\n<li><strong>Oil-in-water sensor<\/strong> where the intake risks industrial discharge upstream<\/li>\n<\/ul>\n<p>The most common SWRO membrane damage mode remains chlorine exposure. Shanghai ChiMay&rsquo;s residual chlorine transmitters address this at low ppb sensitivity.<\/p>\n<h2 id=\"stage-3-seawater-reverse-osmosis\"><span class=\"ez-toc-section\" id=\"Stage_3_Seawater_Reverse_Osmosis\"><\/span>Stage 3: Seawater Reverse Osmosis<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>The SWRO stage does the heavy lifting: reducing TDS from 35,000+ mg\/L to 200\u2013500 mg\/L (permeate conductivity around 400\u2013800 \u00b5S\/cm). Key measurements:<\/p>\n<ul>\n<li><strong>Feed conductivity<\/strong> for baseline logging<\/li>\n<li><strong>Permeate conductivity<\/strong> for real-time membrane integrity monitoring \u2014 a rising trend is the fastest indicator of membrane damage<\/li>\n<li><strong>Reject conductivity<\/strong> for recovery rate verification<\/li>\n<li><strong>Feed and permeate pH<\/strong> to detect boron rejection anomalies<\/li>\n<li><strong>Turbine <a href=\"\/tag\/flow-meter\/\" target=\"_blank\"><strong>flow meter<\/strong><\/a><\/strong> on the permeate and reject streams for a mass balance check<\/li>\n<\/ul>\n<p>Shanghai ChiMay&rsquo;s conductivity meters are installed on every SWRO train, often with permeate probes on each pressure vessel outlet to isolate a failing element without shutting down the whole train.<\/p>\n<h2 id=\"stage-4-second-pass-ro-or-ion-exchange\"><span class=\"ez-toc-section\" id=\"Stage_4_Second-Pass_RO_or_Ion_Exchange\"><\/span>Stage 4: Second-Pass RO or Ion Exchange<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Depending on the design, a green hydrogen SWRO plant will follow the first-pass RO with either a second-pass RO or a direct ion-exchange stage. Instrumentation stays the same as a conventional two-pass system, with conductivity as the primary indicator of second-pass efficiency (typically dropping from 400 \u00b5S\/cm to &lt;20 \u00b5S\/cm).<\/p>\n<p>Two things matter here that don&rsquo;t matter in a first-pass RO:<\/p>\n<ul>\n<li><strong>Boron sensitivity.<\/strong> Boron passes preferentially through most polyamide membranes. Modern hydrogen sites usually configure the second-pass at elevated pH to improve boron rejection.<\/li>\n<li><strong>pH stability.<\/strong> Because pH is being deliberately shifted, pH probes must be robust and well-maintained.<\/li>\n<\/ul>\n<p>Shanghai ChiMay&rsquo;s pH electrodes in this stage carry high-alkaline-tolerant glass, which lasts far longer at pH 9.5\u201310 than general-purpose electrodes.<\/p>\n<h2 id=\"stage-5-polishing-to-ultrapure\"><span class=\"ez-toc-section\" id=\"Stage_5_Polishing_to_Ultrapure\"><\/span>Stage 5: Polishing to Ultrapure<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>The final stage brings the water into the electrolyzer-grade range: \u22640.1 \u00b5S\/cm, \u22645 ppb DO, \u22645 ppb silica, and \u22641 ppb heavy metals. Mixed-bed ion exchange or electrodeionization (EDI) does the work, followed by degassing to remove residual dissolved oxygen and CO\u2082.<\/p>\n<p>Measurement density here is the highest in the plant:<\/p>\n<ul>\n<li><strong>Ultrapure conductivity electrodes<\/strong> at every unit&rsquo;s inlet and outlet<\/li>\n<li><strong><a href=\"\/tag\/Optical-DO\" target=\"_blank\"><strong>Optical DO<\/strong><\/a> transmitters<\/strong> after the degasser<\/li>\n<li><strong>In-line pH electrodes<\/strong> for polished water quality cross-checking<\/li>\n<li><strong>Trace silica and iron analyzers<\/strong> at strategic points<\/li>\n<li><strong>Turbine <a href=\"\/tag\/flow-meter\/\" target=\"_blank\"><strong>flow meter<\/strong><\/a><\/strong> on the polished water outlet to the stack<\/li>\n<\/ul>\n<p>Shanghai ChiMay&rsquo;s ultrapure conductivity portfolio was developed specifically for this stage. The low-cell-constant electrodes read reliably down to 0.005 \u00b5S\/cm and hold that stability over months.<\/p>\n<h2 id=\"stage-6-stack-feed\"><span class=\"ez-toc-section\" id=\"Stage_6_Stack_Feed\"><\/span>Stage 6: Stack Feed<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>The final stretch \u2014 from the polishing outlet to the electrolyzer stack \u2014 is short but critical. It usually includes:<\/p>\n<ul>\n<li><strong>A final conductivity guard probe<\/strong> immediately upstream of the anode inlet<\/li>\n<li><strong>A DO transmitter<\/strong> at the same point<\/li>\n<li><strong>A <a href=\"\/tag\/flow-meter\/\" target=\"_blank\"><strong>flow meter<\/strong><\/a><\/strong> on the feed line<\/li>\n<li><strong>A safety interlock<\/strong> that trips the stack if any parameter exceeds spec<\/li>\n<\/ul>\n<p>This &ldquo;safety photograph&rdquo; is what protects the catalyst from any late-stage contamination. Shanghai ChiMay&rsquo;s practice is to make this the most stable, most redundant measurement in the plant \u2014 three-year drift under 0.005 \u00b5S\/cm, verified independently at every routine service.<\/p>\n<h2 id=\"what-the-full-chain-costs\"><span class=\"ez-toc-section\" id=\"What_the_Full_Chain_Costs\"><\/span>What the Full Chain Costs<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>For a 100 MW seawater-fed green hydrogen project, the full water chain from intake to stack represents roughly USD 8\u201320 million in capital, depending on the local site conditions and permitting. Instrumentation is 2\u20134 % of that total but touches every stage. Skimping on instrumentation to save 1 % of CAPEX regularly results in 5\u201310 % of hydrogen output being lost over the plant lifetime through undetected water quality events.<\/p>\n<p>Shanghai ChiMay works with EPCs and developers to right-size the sensor budget across the chain \u2014 enough measurement to catch problems, not so much that it becomes noise.<\/p>\n<h2 id=\"bringing-it-together\"><span class=\"ez-toc-section\" id=\"Bringing_It_Together\"><\/span>Bringing It Together<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>The seawater-to-stack water chain is one of the great engineering stories of the green hydrogen buildout. Coastal projects turning ocean water into hydrogen molecules at 34 % renewable-electron-to-H\u2082 efficiency depend on getting every stage of the water treatment right. That, in turn, depends on the measurement layer that lets operators see what is happening in real time. This field guide is the compressed version of what Shanghai ChiMay&rsquo;s teams see working every day at some of the largest green hydrogen sites in the world. The message is simple: from ocean to anode, every stage needs the right sensor. Skip any of them, and the plant pays for it downstream.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>title: &ldquo;From Seawater to Stack: A Field Guide to the Green Hydrogen Water Chain by Shanghai ChiMay&rdquo; description: &ldquo;A field-oriented walkthrough of the green hydrogen water chain from seawater intake to electrolyzer stack, with monitoring practices from Shanghai ChiMay.&rdquo; type: high-traffic-imitation theme: Green Hydrogen &amp; Electrolyzer Feedwater date: 2026-07-06 From Seawater to Stack: A Field&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false},"categories":[1],"tags":[174,11034,134481,193],"translation":{"provider":"WPGlobus","version":"2.12.0","language":"fr","enabled_languages":["en","es","fr","ru","ar"],"languages":{"en":{"title":true,"content":true,"excerpt":false},"es":{"title":false,"content":false,"excerpt":false},"fr":{"title":false,"content":false,"excerpt":false},"ru":{"title":false,"content":false,"excerpt":false},"ar":{"title":false,"content":false,"excerpt":false}}},"_links":{"self":[{"href":"https:\/\/shchimay.com\/fr\/wp-json\/wp\/v2\/posts\/31170"}],"collection":[{"href":"https:\/\/shchimay.com\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/shchimay.com\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/shchimay.com\/fr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/shchimay.com\/fr\/wp-json\/wp\/v2\/comments?post=31170"}],"version-history":[{"count":0,"href":"https:\/\/shchimay.com\/fr\/wp-json\/wp\/v2\/posts\/31170\/revisions"}],"wp:attachment":[{"href":"https:\/\/shchimay.com\/fr\/wp-json\/wp\/v2\/media?parent=31170"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/shchimay.com\/fr\/wp-json\/wp\/v2\/categories?post=31170"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/shchimay.com\/fr\/wp-json\/wp\/v2\/tags?post=31170"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}