{"id":11647,"date":"2026-07-14T16:50:15","date_gmt":"2026-07-14T08:50:15","guid":{"rendered":"https:\/\/activatedcarbon.net\/?p=11647"},"modified":"2026-07-14T16:50:18","modified_gmt":"2026-07-14T08:50:18","slug":"activated-carbon-for-h%e2%82%82s-removal","status":"publish","type":"post","link":"https:\/\/activatedcarbon.net\/fr\/activated-carbon-for-h%e2%82%82s-removal\/","title":{"rendered":"Activated Carbon for H\u2082S Removal"},"content":{"rendered":"
\"\"<\/figure>\n\n\n\n

Introduction<\/h2>\n\n\n\n

Hydrogen sulfide (H\u2082S) is one of the most troublesome contaminants in biogas, sewage gas, landfill gas, and various industrial gas streams. This colorless, flammable gas is instantly recognizable by its “rotten egg” odor at concentrations as low as 0.5 ppm \u2014 but its real damage goes far beyond the nose. In biogas cogeneration (CHP) engines, H\u2082S combustion produces sulfuric acid (H\u2082SO\u2084) vapor that corrodes engine cylinders, exhaust heat exchangers, and catalysts, shortening engine life from 60,000 hours to as little as 10,000 hours. Even trace H\u2082S in natural gas pipelines causes stress corrosion cracking in steel infrastructure.<\/p>\n\n\n\n

At Zhulin Carbon, we manufacture KOH-impregnated coal-based columnar activated carbon specifically engineered for high-capacity H\u2082S removal. In this guide, we explain how impregnated carbon works, why KOH impregnation dramatically boosts performance, and \u2014 most importantly \u2014 we share a real customer case study from a biogas plant showing exactly how our carbon performs in the field.<\/p>\n\n\n\n

How H\u2082S Harms Your Equipment<\/strong><\/h2>\n\n\n\n

Whether your gas is biogas from an anaerobic digester, sewage gas from a wastewater treatment plant, or landfill gas from a municipal waste site, H\u2082S is almost always present \u2014 typically at 500\u20135,000 ppm, sometimes exceeding 10,000 ppm. The damage cascade is well documented:<\/p>\n\n\n\n

    \n
  • CHP gas engines (Jenbacher, Caterpillar, MWM) typically require H\u2082S <250 ppm (some <100 ppm). H\u2082S combustion forms H\u2082SO\u2084, corroding cylinder liners, valves, and turbochargers.<\/li>\n\n\n\n
  • Oxidation catalysts and SCR NOx catalysts are deactivated by sulfur. H\u2082S must typically be <10 ppm to protect catalyst systems.<\/li>\n\n\n\n
  • Natural gas pipeline specifications limit H\u2082S to <4 ppm (or even <0.25 ppm for some grids).<\/strong><\/li>\n\n\n\n
  • H\u2082S is acutely toxic at 700 ppm (fatal within minutes); OSHA limits are 10 ppm (8-hour TWA) and 15 ppm (STEL).<\/li>\n\n\n\n
  • Membrane and PSA upgrading systems require H\u2082S <50 ppm to prevent membrane and adsorbent damage.<\/li>\n<\/ul>\n\n\n\n

    Activated carbon desulfurization is one of the simplest, most reliable, and most cost-effective methods for H\u2082S removal \u2014 especially for small-to-medium biogas plants (50\u20131,000 m\u00b3\/h) where the capital cost of biological scrubbers or chemical washers is hard to justify.<\/p>\n\n\n\n

    How KOH-Impregnated Carbon Removes H\u2082S<\/strong><\/h2>\n\n\n\n

    Unmodified activated carbon adsorbs H\u2082S through weak physical forces, achieving only moderate capacity (typically 5\u201315 wt%). The breakthrough comes from chemical impregnation with potassium hydroxide (KOH), which transforms the carbon from a simple adsorbent into a powerful chemical scrubber.<\/p>\n\n\n\n

    When moist biogas passes through a bed of KOH-impregnated carbon, three reactions occur simultaneously on the carbon surface:<\/p>\n\n\n\n

      \n
    • KOH reacts directly with H\u2082S in an acid-base reaction: 2KOH + H\u2082S \u2192 K\u2082S + 2H\u2082O. The H\u2082S is permanently converted to solid potassium sulfide, locked within the carbon pore structure.<\/li>\n\n\n\n
    • The alkaline KOH surface catalyzes the oxidation of H\u2082S by trace oxygen in the gas stream: H\u2082S + \u00bdO\u2082 \u2192 S\u2070 + H\u2082O (at low humidity) or H\u2082S + 2O\u2082 \u2192 H\u2082SO\u2084 (at high humidity). The elemental sulfur or sulfuric acid is retained in the pores.<\/li>\n\n\n\n
    • The underlying carbon micropore structure provides additional adsorption capacity for H\u2082S and other organic sulfur compounds (mercaptans, siloxanes) that may be present in biogas.<\/li>\n<\/ul>\n\n\n\n

      The result: KOH-impregnated columnar carbon achieves H\u2082S adsorption capacities of 25\u201360 wt% \u2014 meaning 1 kg of carbon can remove 250\u2013600 grams of H\u2082S. This is 5\u201310 times higher than unmodified carbon, dramatically reducing carbon consumption and replacement frequency.<\/p>\n\n\n\n

      Why Columnar (Cylindrical) Carbon with KOH Impregnation?<\/strong><\/h2>\n\n\n\n
      \"\"<\/figure>\n\n\n\n

      For H\u2082S removal from biogas and similar gas streams, the physical form of the carbon matters as much as its chemistry. Coal-based columnar activated carbon, impregnated with KOH, offers the ideal combination of properties:<\/p>\n\n\n\n

        \n
      • The uniform cylindrical pellets (typically 4 mm diameter) create regular gas flow channels in the filter bed, minimizing pressure drop. This is essential for biogas blowers that operate at low differential pressures (typically <50 mbar).<\/li>\n\n\n\n
      • Our impregnation process distributes KOH evenly throughout the pellet cross-section, not just on the outer surface. This ensures that the entire carbon mass participates in the H\u2082S reaction, maximizing utilization.<\/li>\n\n\n\n
      • A carbon tetrachloride adsorption value of 50% provides sufficient base pore development to support the impregnated chemistry while maintaining structural integrity after KOH loading.<\/li>\n\n\n\n
      • The coal-based columnar structure resists attrition from gas flow, vibration, and handling. Soft carbons would generate alkaline dust that contaminates downstream equipment.<\/li>\n\n\n\n
      • The KOH-impregnated carbon is designed to operate in water-saturated biogas (RH 80\u2013100%). The moisture actually enhances the catalytic oxidation reaction \u2014 unlike desiccant-type carbons that lose capacity in humid gas.<\/li>\n\n\n\n
      • Coal-based columnar carbon is significantly cheaper than coconut-shell-based impregnated carbons, making it the preferred choice for high-volume, consumable desulfurization applications.<\/li>\n<\/ul>\n\n\n\n

        Technical Parameters of Our KOH-Impregnated Columnar Carbon<\/strong><\/h3>\n\n\n\n
        Param\u00e8tres<\/strong><\/td>Unit\u00e9<\/strong><\/td>Sp\u00e9cifications<\/strong><\/td>Why It Matters for H\u2082S Removal<\/strong><\/td><\/tr>
        Mati\u00e8res premi\u00e8res<\/strong><\/td>\u2014<\/td>Selected anthracite & bituminous coal<\/td>High carbon content, rigid structure<\/td><\/tr>
        Processus de fabrication<\/strong><\/td>\u2014<\/td>Extrusion \u2192 Carbonization \u2192 Steam activation \u2192 KOH impregnation \u2192 Drying<\/td>Engineered surface chemistry for H\u2082S chemisorption<\/td><\/tr>
        Diam\u00e8tre des granul\u00e9s<\/strong><\/td>mm<\/td>4.0 (also 3.0 \/ 1.5 available)<\/td>Standard 4 mm for biogas filters<\/td><\/tr>
        Je suis enceinte<\/strong><\/td>\u2014<\/td>Hydroxyde de potassium (KOH)<\/td>Transforms carbon into chemical scrubber<\/td><\/tr>
        KOH Loading<\/strong><\/td>wt%<\/td>5 \u2013 10 (typical 6\u20138)<\/td>Optimized for maximum H\u2082S capacity<\/td><\/tr>
        CTC Adsorption<\/strong><\/td>% (wt)<\/td>\u2265 50<\/td>Base pore development; supports impregnated chemistry<\/td><\/tr>
        Iodine Number (pre-impregnation)<\/strong><\/td>mg\/g<\/td>\u2265 850 \u2013 950<\/td>Underlying pore quality indicator<\/td><\/tr>
        Specific Surface Area (BET)<\/strong><\/td>m\u00b2\/g<\/td>\u2265 800 \u2013 1,000<\/td>Adequate pore volume for reaction products<\/td><\/tr>
        Apparent \/ Bulk Density<\/strong><\/td>g\/cm\u00b3<\/td>0.50 \u2013 0.60<\/td>Higher density due to KOH loading<\/td><\/tr>
        Hardness \/ Abrasion Number<\/strong><\/td>%<\/td>\u2265 95<\/td>Resists dusting under gas flow<\/td><\/tr>
        Contenu en cendres<\/strong><\/td>%<\/td>\u2264 15 (includes KOH)<\/td>KOH counted as ash; normal for impregnated carbon<\/td><\/tr>
        Moisture (as packed)<\/strong><\/td>%<\/td>\u2264 10<\/td>Some residual moisture is acceptable<\/td><\/tr>
        pH (surface)<\/strong><\/td>\u2014<\/td>Strongly alkaline (>10)<\/td>Critical for acid-base H\u2082S neutralization<\/td><\/tr>
        Pellet Length<\/strong><\/td>mm<\/td>5 \u2013 20 (typical)<\/td>Uniform geometry for even gas distribution<\/td><\/tr>
        H\u2082S Adsorption Capacity<\/strong><\/td>wt%<\/td>25 \u2013 60 (typical, lab-determined)<\/td>5\u201310\u00d7 higher than unmodified carbon; depends on humidity & O\u2082<\/td><\/tr>
        H\u2082S Removal Efficiency<\/strong><\/td>%<\/td>> 98 (typical)<\/td>Reduces H\u2082S from thousands of ppm to target<\/td><\/tr>
        Operating Temperature<\/strong><\/td>\u00b0C<\/td>5 \u2013 50<\/td>Typical biogas digester temperature range<\/td><\/tr>
        Operating Humidity<\/strong><\/td>% RH<\/td>60 \u2013 100 (optimal 80\u2013100%)<\/td>Moisture enhances catalytic oxidation<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

        Customer Case Study: Biogas Plant H\u2082S Treatment in Practice<\/strong><\/h2>\n\n\n\n

        To illustrate how these specifications translate into real-world performance, here is a project we completed for a biogas plant operator.<\/p>\n\n\n\n

        \n

        Case Study: Biogas Digester H\u2082S Desulfurization<\/h2>\n\n
        \n

        Application :<\/strong> Anaerobic digester biogas desulfurization (for CHP engine protection)<\/p>\n

        Biogas Flow Rate:<\/strong> 80 m\u00b3\/h<\/p>\n

        Inlet H\u2082S Concentration:<\/strong> 1,700 ppm<\/p>\n

        Treatment Target:<\/strong> Outlet H\u2082S \u2264 25\u201350 ppm<\/p>\n <\/div>\n\n

        \n

        System Configuration:<\/h4>\n
          \n
        • Two parallel activated carbon filters (lead-lag switchable)<\/li>\n
        • Each filter holds 750 kg of carbon<\/li>\n
        • Carbon grade: 4 mm KOH-impregnated columnar carbon, CTC \u226550%<\/li>\n <\/ul>\n <\/div>\n\n
          \n

          Design Performance & Carbon Consumption:<\/h4>\n \n \n \n \n \n \n
          Outlet Target<\/th>\n Expected Carbon Usage<\/th>\n Monthly Consumption<\/th>\n Filter Cycles<\/th>\n <\/tr>\n <\/thead>\n
          \u2264 25 ppm H\u2082S<\/td>\n ~46 kg\/day<\/td>\n \u2248 1,380 kg\/month<\/td>\n \u2248 1.84 tanks\/month<\/td>\n <\/tr>\n
          \u2264 50 ppm H\u2082S<\/td>\n ~45 kg\/day<\/td>\n \u2248 1,345 kg\/month<\/td>\n \u2248 1.79 tanks\/month<\/td>\n <\/tr>\n <\/tbody>\n <\/table>\n <\/div>\n\n
          \n

          Analysis & Key Takeaways:<\/h4>\n
            \n
          • At 1,700 ppm inlet and 80 m\u00b3\/h flow, the system must remove ~136 g H\u2082S\/h (3.3 kg H\u2082S\/day).<\/li>\n
          • Our 4mm KOH-impregnated carbon achieves an effective H\u2082S working capacity of ~7\u20138 wt% under these operating conditions, consuming ~45\u201346 kg\/day.<\/li>\n
          • The two 750 kg filters in parallel provide a combined 1,500 kg carbon inventory, giving approximately 32\u201333 days of continuous operation per full charge.<\/li>\n
          • The operator switches the lead\/lag position monthly, replacing the saturated filter while the second filter continues treatment \u2014 ensuring zero downtime.<\/li>\n
          • The marginal difference between 25 ppm and 50 ppm targets (only ~35 kg\/month) demonstrates the carbon’s steep adsorption isotherm: most H\u2082S is removed in the early stage of the bed, and tightening the outlet target adds minimal cost.<\/li>\n <\/ul>\n <\/div>\n<\/div>\n\n\n\n

            How to Design an H\u2082S Removal System with Impregnated Carbon<\/strong><\/h2>\n\n\n\n

            Based on our experience across hundreds of biogas, sewage gas, and landfill gas projects, here is a practical design approach:<\/p>\n\n\n\n

            1. Measure H\u2082S and gas composition: <\/strong>Test the raw gas for H\u2082S concentration (ppm), flow rate (m\u00b3\/h), temperature, humidity, O\u2082 content, and CO\u2082 content. H\u2082S levels can vary daily, so take multiple samples over a week. Also check for siloxanes (common in sewage gas) and VOCs that may compete for adsorption sites.<\/p>\n\n\n\n

            2. Calculate the H\u2082S load: <\/strong>H\u2082S load (kg\/day) = Flow rate (m\u00b3\/h) \u00d7 H\u2082S (ppm) \u00d7 24h \u00d7 34\/22.4 \u00d7 10\u207b\u2076. This determines the carbon consumption rate and expected filter service life.<\/p>\n\n\n\n

            3. Select the target outlet concentration: <\/strong>For CHP engines: typically 25\u201350 ppm. For biomethane upgrading (membrane\/PSA): 10\u201350 ppm. For pipeline injection: <4 ppm. Tighter targets increase carbon consumption but protect downstream equipment.<\/p>\n\n\n\n

            4. Size the carbon filter: <\/strong>Determine EBCT (Empty Bed Contact Time). For KOH-impregnated carbon: minimum 15\u201325 seconds for biogas at moderate H\u2082S (<2,000 ppm); 25\u201340 seconds for high H\u2082S (>2,000 ppm). Use two filters in parallel or lead-lag for continuous operation.<\/p>\n\n\n\n

            5. Ensure proper operating conditions: <\/strong>Gas temperature: 5\u201350\u00b0C (ambient is ideal). Humidity: 80\u2013100% RH is optimal for the catalytic oxidation reaction. If the gas is too dry, inject steam or water mist upstream. Remove liquid water droplets with a demister before the carbon bed to prevent flooding.<\/p>\n\n\n\n

            6. Monitor and replace: <\/strong>Install H\u2082S sensors at inlet and outlet. When the outlet concentration exceeds the target, replace the carbon in the lead filter. Spent KOH-impregnated carbon containing sulfur\/sulfide should be disposed of according to local regulations \u2014 it is typically non-hazardous but may have a high pH.<\/p>\n\n\n\n

            Where Is This Technology Applied?<\/strong><\/h2>\n\n\n\n
              \n
            • Biogas plants (agricultural, food waste, animal manure) \u2014 CHP engine protection<\/li>\n\n\n\n
            • Wastewater treatment plants \u2014 sewage gas \/ digester gas desulfurization<\/li>\n\n\n\n
            • Landfill gas collection \u2014 LFG-to-energy projects<\/li>\n\n\n\n
            • Industrial biogas \u2014 palm oil mill effluent (POME), brewery, distillery waste<\/li>\n\n\n\n
            • Natural gas processing \u2014 sweetening low-volume sour gas streams<\/li>\n\n\n\n
            • Petrochemical and refinery \u2014 tail gas and vent gas H\u2082S polishing<\/li>\n\n\n\n
            • Geothermal power \u2014 non-condensable gas H\u2082S removal<\/li>\n\n\n\n
            • Pulp and paper \u2014 digester gas and recovery boiler emissions<\/li>\n<\/ul>\n\n\n\n

              Why Choose Zhulin Carbon for H\u2082S Removal?<\/strong><\/h2>\n\n\n\n

              Zhulin Carbon has supplied KOH-impregnated columnar carbon to biogas plants, wastewater treatment facilities, and landfill gas projects worldwide. Here is what sets us apart:<\/p>\n\n\n\n

                \n
              • Our KOH loading is precisely controlled at 6\u20138 wt% to maximize H\u2082S capacity without pellet softening or dusting.<\/li>\n\n\n\n
              • Our 4 mm CTC50 KOH carbon delivers 25\u201360 wt% H\u2082S working capacity under typical biogas conditions \u2014 verified in field projects like the case study above.<\/li>\n\n\n\n
              • Uniform 4 mm diameter with \u226595% hardness ensures low pressure drop and minimal fines, even after months of operation.<\/li>\n\n\n\n
              • We can adjust KOH loading and pellet diameter to match your specific gas composition and filter design. Other impregnants (NaOH, KI, CuO) also available for specialized applications.<\/li>\n\n\n\n
              • Our engineers help you calculate carbon consumption, size filters, optimize EBCT, and design lead-lag switching protocols.<\/li>\n\n\n\n
              • Available in 25 kg bags, 500 kg \/ 1,000 kg super sacks, or bulk delivery. We maintain stock for rapid resupply to minimize filter downtime.<\/li>\n\n\n\n
              • Every batch tested for CTC, pellet diameter, hardness, bulk density, and KOH loading per GB\/ASTM standards.<\/li>\n<\/ul>\n\n\n\n

                Conclusion<\/strong><\/h2>\n\n\n\n

                H\u2082S removal is a critical treatment step for any biogas, sewage gas, or landfill gas utilization project. KOH-impregnated coal-based columnar activated carbon offers the optimal combination of high H\u2082S capacity (25\u201360 wt%), low pressure drop, reliable performance in humid gas, and cost-effectiveness for small-to-medium gas flows. As demonstrated in our biogas plant case study \u2014 treating 80 m\u00b3\/h of biogas with 1,700 ppm H\u2082S down to 25\u201350 ppm \u2014 our 4 mm KOH-impregnated carbon delivers predictable performance at a consumption rate of approximately 1,345\u20131,380 kg\/month, protecting CHP engines and ensuring compliant gas quality.<\/p>\n\n\n\n

                Planning a biogas or industrial gas desulfurization project? Contact our technical team at info@zhulincarbon.com or call +86-19949132731 for free samples, H\u2082S capacity testing, and expert system sizing support.<\/p>","protected":false},"excerpt":{"rendered":"

                Introduction Hydrogen sulfide (H\u2082S) is one of the most troublesome contaminants in biogas, sewage gas, landfill gas, and various industrial gas streams. This colorless, flammable gas is instantly recognizable by its “rotten egg” odor at concentrations as low as 0.5 ppm \u2014 but its real damage goes far beyond the nose. In biogas cogeneration (CHP) […]<\/p>\n","protected":false},"author":1,"featured_media":11675,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_uag_custom_page_level_css":"","footnotes":""},"categories":[76],"tags":[],"class_list":["post-11647","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-activated-carbon-manufacturers"],"uagb_featured_image_src":{"full":["https:\/\/activatedcarbon.net\/wp-content\/uploads\/2026\/07\/Activated-Carbon-for-H\u2082S-Removal.png",840,450,false],"thumbnail":["https:\/\/activatedcarbon.net\/wp-content\/uploads\/2026\/07\/Activated-Carbon-for-H\u2082S-Removal-150x150.png",150,150,true],"medium":["https:\/\/activatedcarbon.net\/wp-content\/uploads\/2026\/07\/Activated-Carbon-for-H\u2082S-Removal-300x161.png",300,161,true],"medium_large":["https:\/\/activatedcarbon.net\/wp-content\/uploads\/2026\/07\/Activated-Carbon-for-H\u2082S-Removal-768x411.png",768,411,true],"large":["https:\/\/activatedcarbon.net\/wp-content\/uploads\/2026\/07\/Activated-Carbon-for-H\u2082S-Removal.png",800,429,false],"1536x1536":["https:\/\/activatedcarbon.net\/wp-content\/uploads\/2026\/07\/Activated-Carbon-for-H\u2082S-Removal.png",840,450,false],"2048x2048":["https:\/\/activatedcarbon.net\/wp-content\/uploads\/2026\/07\/Activated-Carbon-for-H\u2082S-Removal.png",840,450,false],"trp-custom-language-flag":["https:\/\/activatedcarbon.net\/wp-content\/uploads\/2026\/07\/Activated-Carbon-for-H\u2082S-Removal-18x10.png",18,10,true]},"uagb_author_info":{"display_name":"zhulincarbon","author_link":"https:\/\/activatedcarbon.net\/fr\/author\/zhulincarbon\/"},"uagb_comment_info":0,"uagb_excerpt":"Introduction Hydrogen sulfide (H\u2082S) is one of the most troublesome contaminants in biogas, sewage gas, landfill gas, and various industrial gas streams. This colorless, flammable gas is instantly recognizable by its “rotten egg” odor at concentrations as low as 0.5 ppm \u2014 but its real damage goes far beyond the nose. In biogas cogeneration (CHP)\u2026","_links":{"self":[{"href":"https:\/\/activatedcarbon.net\/fr\/wp-json\/wp\/v2\/posts\/11647","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/activatedcarbon.net\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/activatedcarbon.net\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/activatedcarbon.net\/fr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/activatedcarbon.net\/fr\/wp-json\/wp\/v2\/comments?post=11647"}],"version-history":[{"count":0,"href":"https:\/\/activatedcarbon.net\/fr\/wp-json\/wp\/v2\/posts\/11647\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/activatedcarbon.net\/fr\/wp-json\/wp\/v2\/media\/11675"}],"wp:attachment":[{"href":"https:\/\/activatedcarbon.net\/fr\/wp-json\/wp\/v2\/media?parent=11647"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/activatedcarbon.net\/fr\/wp-json\/wp\/v2\/categories?post=11647"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/activatedcarbon.net\/fr\/wp-json\/wp\/v2\/tags?post=11647"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}