KOH and NaOH pellets alongside impregnated activated carbon for H₂S removal

H₂S Specialist

KOH Impregnated Activated Carbon

Q: Why choose KOH over NaOH impregnated carbon?

KOH offers higher H₂S breakthrough capacity per unit volume compared to NaOH. KOH-impregnated pellets are the global industry standard for biogas desulfurization because potassium hydroxide has better solubility, faster reaction kinetics with H₂S, and more uniform distribution across the carbon pore structure.

Q: What H₂S inlet concentration can KOH carbon handle?

KOH impregnated carbon effectively treats H₂S from 10 ppm to 10,000+ ppm. For concentrations above 3,000 ppm, we recommend a two-stage system or a larger bed volume. Contact our engineers with your gas composition for optimal bed sizing.

Q: How long does a KOH carbon bed last before replacement?

Bed life depends on H₂S inlet concentration, gas flow, and moisture. At 2,000 ppm H₂S inlet, a properly sized bed typically lasts 6–18 months. We provide a bed-sizing calculation based on your gas volume and target breakthrough so you can budget change-out intervals accurately.

Q: Is KOH impregnated carbon regenerable?

No. Once the KOH reacts with H₂S it forms elemental sulfur and potassium salts that plug the pores — thermal regeneration is not practical or economical. Spent carbon is replaced with fresh media. This is normal for chemisorption desulfurization media and is why we focus on maximizing single-pass working capacity.

Q: Why does the packaging use a sealed PE liner?

KOH is hygroscopic — it absorbs atmospheric moisture. Uncontrolled moisture uptake during storage reduces H₂S capacity before the carbon is even installed. Our 25 kg and jumbo bags use a heat-sealed PE inner liner as a moisture barrier so the product arrives at spec. Keep bags sealed until loading into the vessel.

Industry-standard KOH-impregnated 4mm pellets for H₂S removal from biogas, natural gas, and landfill gas. Working capacity 0.15–0.30 g/cm³.

⚡ Quick Answer

KOH impregnated activated carbon is coal-based Φ3–4mm pellet carbon loaded with 8–15% potassium hydroxide that chemically converts hydrogen sulfide (H₂S) into elemental sulfur and potassium salts. It removes H₂S from biogas, natural gas, and landfill gas at over 99.9% efficiency, cutting outlet levels below 1 ppm with a typical bed life of 6–18 months.

Impregnation Rate: 8 – 15% KOH by weight
H₂S Removal: > 99.9% (outlet < 1 ppm)
Working Capacity: 0.15 – 0.30 g/cm³
Bed Life @ 2,000 ppm: 6 – 18 months

Product Overview

KOH (potassium hydroxide) impregnated activated carbon is the global standard for removing hydrogen sulfide (H₂S) and other acid gases from biogas, natural gas, landfill gas, and industrial exhaust. The alkaline impregnant reacts chemically with H₂S on the carbon surface, converting it to elemental sulfur and potassium sulfide — achieving removal efficiencies above 99%.

Our KOH-impregnated pellets use high-hardness coal-based extruded carbon as the substrate, ensuring uniform gas distribution, low pressure drop, and long service life. Available in Φ3mm and Φ4mm with impregnation rates from 8% to 15% by weight.

Key Applications

Biogas H₂S desulfurization
Natural gas sweetening
Landfill gas purification
Wastewater odor control (WWTP)
Sewage pump station ventilation
Rendering plant emission control
Chemical plant acid gas scrubbing
Anaerobic digester off-gas

Typical Performance in Biogas Systems

Parameter	Typical Value
H₂S inlet concentration	500 – 5,000 ppm
H₂S outlet (after KOH AC bed)	< 1 ppm
Removal efficiency	> 99.9%
Bed life at 2,000 ppm H₂S inlet	6 – 18 months
Recommended EBCT (empty bed contact time)	3 – 5 seconds
Max operating temperature	60 °C
Optimal relative humidity	40 – 80% RH

Data based on EN 12195 / ASTM D6646 test protocol. Actual bed life depends on gas composition, moisture, and flow rate. Contact us for a full bed-sizing calculation.

Application Example

Municipal Wastewater Plant — 500 m³/hr Biogas, Southeast Asia

A municipal WWTP processing 50,000 m³/day of sewage generates biogas with 2,000–4,500 ppm H₂S. Two 600-liter vessels filled with 8% KOH-impregnated 4mm pellets achieved H₂S outlet <5 ppm continuously for 14 months before the first change-out. The same operator previously used liquid scrubbers, which required daily chemical dosing and had higher OPEX. Carbon total cost of ownership was 40% lower per year.

Read the full case study — 48 tons shipped, 2×40HC

Technical Specifications

Model	HojeeDesulf K-Series
Impregnant	KOH (Potassium Hydroxide)
Impregnation Rate	8 – 15% by weight
Base Carbon	Coal-based extruded pellet
Diameter	Φ 3.0 / 4.0 mm (standard)
H₂S Working Capacity	0.15 – 0.30 g/cm³
Iodine Number	400 – 700 mg/g
pH	10 – 12
Hardness	> 90%
Moisture	< 5%
Bulk Density	0.45 – 0.55 g/cm³
Bed Pressure Drop	Low (uniform pellet geometry)

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Other Impregnated Products

Sulfur Impregnated — Mercury →Silver Impregnated — Antibacterial →KMnO₄ Impregnated — VOC →KI Impregnated — Mercury/Iodine →CuO / MgO Impregnated — HCN/Arsine →K₂CO₃ Impregnated — Low-Corrosivity H₂S →H₃PO₄ Impregnated — Ammonia/Amines →← All Impregnated AC

Why KOH Carbon vs Alternatives

⚡

Chemical vs Physical

KOH reacts with H₂S permanently — no desorption risk unlike plain GAC which physically holds H₂S and releases it when conditions change.

🔋

Higher Capacity

KOH loading of 8–15% delivers H₂S working capacity of 0.15–0.30 g/cm³, 3× higher than NaOH-impregnated carbon.

💧

Moisture-Assisted

Unlike iron-based media, KOH carbon performance improves slightly in humid conditions (40–80% RH) — ideal for real biogas environments.

🔄

Low Pressure Drop

Extruded 4mm pellet geometry ensures uniform bed packing and low ΔP — critical for small biogas engines with limited blower capacity.

Moisture-Barrier Packaging

25 kg

Sealed PE-lined bags

Heat-sealed moisture barrier for hygroscopic KOH

500 kg

Jumbo bags + PE liner

Sealed against humidity, forklift ready

1000 kg

Super sacks

Bulk biogas / WWTP supply

Custom

OEM packaging

Your brand, free design

KOH is hygroscopic, so every bag uses a heat-sealed PE inner liner to keep the product at spec during transit and storage. Keep bags sealed until the media is loaded into the vessel.

Uniform Pellets, Ready to Ship

Every KOH batch is extruded to a consistent Φ3–4mm pellet geometry before impregnation, then sealed in PE-lined bags and dispatched from our own yard. Consistent pellet size is what keeps bed pressure drop low and gas distribution even across the vessel.

KOH impregnated activated carbon pellets in a sample dish and bulk bags loaded for truck dispatch

Left: sealed bulk bags secured for truck dispatch from our factory yard. Right: Φ4mm KOH-impregnated pellets — uniform length and diameter, low fines.

Frequently Asked Questions

Why choose KOH over NaOH impregnated carbon?

KOH offers higher H₂S breakthrough capacity per unit volume compared to NaOH. KOH-impregnated pellets are the global industry standard for biogas desulfurization because potassium hydroxide has better solubility, faster reaction kinetics with H₂S, and more uniform distribution across the carbon pore structure.

What H₂S inlet concentration can KOH carbon handle?

KOH impregnated carbon effectively treats H₂S from 10 ppm to 10,000+ ppm. For concentrations above 3,000 ppm, we recommend a two-stage system or a larger bed volume. Contact our engineers with your gas composition for optimal bed sizing.

How long does a KOH carbon bed last before replacement?

Bed life depends on H₂S inlet concentration, gas flow, and moisture. At 2,000 ppm H₂S inlet, a properly sized bed typically lasts 6–18 months. We provide a bed-sizing calculation based on your gas volume and target breakthrough so you can budget change-out intervals accurately.

Is KOH impregnated carbon regenerable?

No. Once the KOH reacts with H₂S it forms elemental sulfur and potassium salts that plug the pores — thermal regeneration is not practical or economical. Spent carbon is replaced with fresh media. This is normal for chemisorption desulfurization media and is why we focus on maximizing single-pass working capacity.

Why does the packaging use a sealed PE liner?

KOH is hygroscopic — it absorbs atmospheric moisture. Uncontrolled moisture uptake during storage reduces H₂S capacity before the carbon is even installed. Our 25 kg and jumbo bags use a heat-sealed PE inner liner as a moisture barrier so the product arrives at spec. Keep bags sealed until loading into the vessel.

Need Custom H₂S Removal Carbon?

Share your gas composition, flow rate, and H₂S concentration. Our engineers will size the bed and recommend the optimal KOH loading.

Get Custom Quote