H₂S Removal System

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Product Overview / H₂S Removal System

H₂S Removal System

1. desulfurization technology

Anyang Bakdal Sewage Treatment Facility desulfurization system (1,540 m³/hr)

Uijeongbu Waste Resource Recovery Facility desulfurization system (310 m³/min)

Hyosung Corporation, Ulsan Plant desulfurization system (6,850 m³/hr)

1-1. Overwiew of desulfurization technology

Jumunjin Agro-Industrial Complex Final Wastewater Treatment Plant (670 m³/min)

Biogas is generated during anaerobic digestion by methanogenic bacteria of organic waste resources that can cause environmental pollution, such as sewage sludge, livestock manure, and food waste. This gas typically contains hydrogen sulfide in the range of 500–7,000ppm.

Landfill Gas (LFG)

Gas released during the anaerobic decomposition of organic components contained in landfilled waste. Hydrogen sulfide concentrations typically range from 5 to 18,000 ppm.

Effects of Hydrogen Sulfide Corrosion of piping and equipment

Hydrogen sulfide is a highly corrosive gas that attacks key components of high-value power generation facilities, such as pistons, turbines, and piping, leading to reduced system efficiency and severe equipment damage.
It is a major cause of unplanned shutdowns in power generation facilities.
When released to the atmosphere, it can cause serious respiratory injury; prolonged exposure to concentrations above 500ppm is life-threatening.
H₂S is also a precursor of sulfur oxides (SOx), a regulated air pollutant under the Capital Area total air pollution load management system.

- Legal emission standards


annual average limit	0.02 ppm
24-hour average limit	0.05 ppm
1-hour average limit	0.15 ppm

SOx Emissions from Air Discharge Facilities

2. desulfurization technology

liquid-phase catalytic reaction mechanism


Absorption Step	Components absorbed into the liquid phase are ionized and exist as individual ions, and the distribution of these ions depends on pH.
H₂S(gas) + H₂O → H₂S(aq) + H₂O


Ionization Step	Hydrogen sulfide dissociates in aqueous solution.
H₂S(aq) → H⁺ + HS⁻ K₁ = 6.3 × 10⁻⁸ (at 25℃) HS⁻ → H⁺ + S²⁻ K₂ = 1.3 × 10⁻¹² (at 25℃)


Reaction Step	Ions in the aqueous phase undergo oxidation through electron transfer with the trivalent iron catalyst and precipitate as elemental (solid) sulfur. The reduced iron is converted to the ferrous (Fe²⁺) form, and is then re-oxidized to ferric iron (Fe³⁺) through a regeneration step.
HS⁻ + OH⁻ + Fe³⁺–chelate → S⁰ + H₂O + Fe²⁺–chelate S²⁻ + 2H⁺ + 2OH⁻ + 2Fe³⁺–chelate → S⁰ + 2H₂O + 2Fe²⁺–chelate The reaction between the catalyst and hydrogen sulfide is inferred to proceed as follows: H₂S + Fe³⁺(OH⁻)Ln⁻ → Fe³⁺(SH⁻)Ln⁻ + H₂O Fe³⁺(SH⁻)Ln⁻ → Fe²⁺Ln⁻ + HS⁰ HS⁰ + Fe³⁺(OH⁻)Ln → Fe³⁺Ln⁻ + S⁰ + H₂O Regeneration reaction of the liquid-phase catalyst: O₂(g) → O₂(aq) 4Fe²⁺–chelate + O₂(aq) + 2H₂O → 4Fe³⁺–chelate + 4OH⁻

System configuration

To mitigate piping corrosion caused by hydrogen sulfide, the system is configured as follows

1. Primary and secondary removal of hydrogen sulfide in spray towers 1 and 2
2. Final polishing of residual hydrogen sulfide in the packed tower
3. Discharge of the generated solid sulfur to the outside via a filter press
4. Regeneration of the liquid-phase catalyst that has reacted with hydrogen sulfide by air oxidation

Reactor Configuration

3. Comparison of Desulfurization Technologies

* Design basis: gas flow rate 20,000m³/day (H₂S inlet concentration 2,000ppm, outlet concentration 30ppm)

criteria	Iron-chelate liquid-phase catalytic process BNE Tech Co., Ltd.	Wet catalytic oxidation process	Wet chemical scrubber tower	Ion exchange process	Dry desulfurization tower
removal mechanism	Hydrogen sulfide is reacted with oxygen in an iron-chelate catalyst solution and precipitated as elemental sulfur for discharge.	Hydrogen sulfide is converted to elemental sulfur through redox reactions catalyzed by an Fe/MgO catalyst.	Hydrogen sulfide is removed through a chemical reaction with sodium hydroxide (NaOH).	Hydrogen sulfide is removed by dispersing sodium hydroxide (NaOH) in ion-exchange resin cartridges.	Hydrogen sulfide is removed by a contact reaction with iron oxide (Fe₂O₃), forming iron sulfate.
Desulfurization catalyst type	Liquid-phase catalyst (iron chelate)	Liquid-phase catalyst (iron chelate)	40% NaOH	5~10% NaOH	Solid iron oxide (Fe₂O₃)
Desulfurization catalyst service life	Semi-permanent use (regenerated and reused)	Consumable (requires periodic chemical dosing)	Consumable (requires periodic chemical dosing)	Consumable (requires periodic chemical dosing)	Replaceable (requires periodic replacement)
Desulfurization catalyst usage method	Reaction by direct circulation of the liquid-phase catalyst	Used by dissolving the powder catalyst in scrubbing water	Diluted with scrubbing water and recirculated	Diluted with scrubbing water and recirculated	Removed through contact reaction with the desulfurizing agent
Operating desulfurization capacity	20,000m³/day	20,000m³/day	20,000m³/day	20,000m³/day	20,000m³/day
Required installation area	80㎡ (L 8m×W 10m×H10m)	176㎡ (L 8m×W22m×H10m)	72㎡ (L 8m×W9m×H15m)	64㎡ (L 8m×W8m×H15m)	56㎡ (L 8m×W7m×H10m)
Required installation area	99% or more	95% or more	90% or more	90% or more	70% or more
Treatment of spent desulfurization waste	Separated solid sulfur is dewatered using an in-house filter press and then discharged as waste. ※The solid sulfur is classified as general waste at the plant.	Waste sludge (catalyst + solid sulfur) is sent to the central dewatering line, dewatered, and then disposed of.	Consigned for treatment as wastewater (designated waste)	Consigned for treatment as wastewater (designated waste)	Spent desulfurizing agent consigned for off-site treatment (designated waste)
advantages	-High H₂S removal efficiency -requires minimal installation space and simple system configuration -Catalyst service life is semi-permanent. -Low operation and maintenance cost. -Excellent chemical treatment performance. -No generation of secondary waste.	-High H₂S removal efficiency -Only partial removal of odor	-Stable treatment performance with high H₂S removal efficiency -Scrubbing function in the desulfurization tower enables partial removal of fine dust and odors	-Stable treatment performance with high H₂S removal efficiency -Scrubbing function in the desulfurization tower enables partial removal of fine dust and odors	-Simple structure and easy maintenance -Low initial capital cost
disadvantages	--Additional labor is required to handle solid sulfur sludge after filter press operation. -High initial capital expenditure for equipment purchase.	-Complex system with a large installation footprint; requires periodic chemical dosing and generates wastewater -Manual handling of powder catalyst causes catalyst dusting and reaction delays (two boxes of material required per charge) -Powder catalyst dust requires installation of an expensive dust collection system -Severe abrasion of mono pumps and other equipment due to Fe/MgO, leading to increased operation and maintenance costs.	-Periodic chemical dosing required (operator-dependent technology) -Caustic filtration uses sodium hydroxide and requires back-extraction facilities, resulting in secondary treatment facilities and additional O&M costs -Increased influent wastewater flow leads to higher O&M costs -Difficult to control hydrogen sulfide in the downstream section	-Requires periodic chemical dosing -Removal of collected waste generates strong odors -Requires periodic replacement of desulfurizing agent -High load for treating high-concentration hydrogen sulfide -Dehumidification equipment is essential

inlet air flow : 20,000/day, inlet hydrogen sulfide concentration : 2,000ppm, outlet concentration(guaranteed) : 5ppm or less

cost category	Iron-chelate liquid catalytic process	Wet catalytic oxidation process	Wet chemical scrubbing(Sodium hydroxide)	Ion-exchange resin process	Dry desulfurization tower
installation cost	KRW860,000,000	KRW840,000,000	KRW7,200,000,000	KRW800,000,000	KRW680,000,000
chemical cost	KRW28,841,900/year	KRW77,672,000 /year	KRW76,650,000 /year	KRW59,130,000 /year	KRW99,280,000 /year
other related cost	KRW17,827,900 /year	KRW37,102,260 /year	KRW46,985,000 /year	KRW46,985,000 /year	KRW20,705,000 /year
maintenance cost	KRW45,841,900	KRW114,774,260	KRW123,635,000	KRW81,594,300	KRW119,985,000

photos of our installed equipment

advantages of applying liquid catalytic desulfurization technology

evaluation criteria	advantages
economic feasibility	• Enables semi-permanent use of the catalyst • Reduces waste disposal costs
operational stability	• Easy pH control with a small amount of stabilizer • Stable regeneration reaction extends catalyst life • High removal efficiency is maintained consistently over the long term
environmental performance	• Enables reuse of the liquid catalyst • Does not generate secondary environmental pollutants from chemical reactions • Allows recycling of recovered sulfur
field applicability and maintainability	• Applicable regardless of inlet concentration • Easy to respond to concentration fluctuations • Easy operation • Convenient quality control and installation

4. Siloxane Removal Technology

- Siloxane Removal System

Siloxane removal unit design

To effectively remove linear siloxanes (L2, L3) and cyclic siloxanes (D4, D5), the upper section of the adsorption tower is filled with activated carbon and the lower section with silica gel.
As activated carbon cannot be regenerated and has a short service life, an adsorbent inlet and discharge port are provided for easy replacement.
A 2-way tower configuration is adopted, with one tower in removal operation and the other in regeneration mode.
When using regenerable silica gel, a hot-air supply unit for thermal regeneration is installed.