Biogas Pretreatment System

A system that removes hydrogen sulfide and siloxane in the gas through chemical reaction and adsorption of the desulfurization agent by passing biogas through a desulfurization tower filled with DeHyS, an iron hydroxide desulfurization agent.


Removal of Hydrogen sulfide and Siloxanes from biogas


Desulfurization agent in powder and pellet form for H2S and siloxane removal from biogas

Iron Hydroxide(Fe(OH)3)

2Fe(OH)3 + 3H2S Fe2S3 + 6H2O

2FeOOH + 3H2S Fe2S3 + 4H2O

biogas iron image biogas iron image
Technical excellence

Removal of fine dust causing substances from biogas(i.e H2S & Siloxanes)

Removal 200 - 10,000 ppm H2S down to ultra low concentration in less than 0.5ppm

100% removal of 5 to 100 mg/m3min of siloxanes

No effect by moisture (High water resistance desulfurization agent)

Advantages in our technology

High ability of simultaneous removals for H2S and siloxanes

A Installation and maintenance cost is 30% economical more than before.

Reference sites

01 Hongcheon/Eco-friendly Energy Town (Manure, Wastewater)

02 Chungju/Food Waste Bio-Energy Center (Food waste)

03 Seoul/Tancheon Wastewater Recover Plant

04 Incheon/Metropolitan Landfill Site

05 Changwon/Changwon Food Waste Bio-Energy Center

06 Iksan/ Sewage Treatment Plant Biogas Ecuipment

Characteristic of Removal System

Hydrogen Sulfide (H2S) Removal System

The necessity of removal(H2S) from biogas

Hydrogen sulfide is an air pollutant that causes toxicity and odor

It mainly occurs in the process of anaerobic decomposition and desulfurization of petrochemical plant.

The sulfur compounds(H2S, SO2) contained in biogas exist in trace amounts, which generate the corrosion and odor-causing substances in the device

When people inhale the hydrogen sulfide released into the atmosphere, it causes central nerve paralysis or suffocation

Hydrogen sulfide (H2S) removal process
hydrogen sulfide

Hydrogen sulfide removal process by using the iron hydroxide (Fe(OH)3)

Siloxanes Removal System

The necessity of siloxanes removal in biogas

A siloxanes generation increases according to landfill of waste chemical products increases

Attachment of silicate to gas turbine, boilers, etc. leads to the increase in facility maintenance costs.

The siloxanes are one of the fine dust-causing substance

When inhaling the siloxane, it is harmful to human health

Biogas dehumidification technology

High efficiency system for hazardous gas removal adopting 2-stages heat exchangers (Parent KR : 10-2300634)

Energy saving by 60%, extended operating time with highdurabiity
Biogas pretreatment system

Biogas impurity removal method and removal system (Parent KR : 10-2196559)

-ppb-grade hydroger sulfide removal rate and prevention of condensate production
Effects of biogas dehumidification

Upgrade in engine efficiency

Lowering the moisture content by 1% leads to the increase of methane(CH4) content by 5%

▶ thus increasing the electrical power by 5%

Complies with supply standards of gas engines

Major engine manufacturers do not allow a moisture and pipe condensate from raw materials.

Reduction of Engine Oil Pollution

Increase in engine oil replacement cycle (1MWe engine 600L)

From 800 hours to 1,600 hours

Corrosion protection of piping and components

A dry gas supplied at low dew point prevents the generation of corrosive acid substances

Siloxanes removal effects (Generator parts life extension)
biogas generator

Biogas Generator

Spark plug

4 to 5 times longer lifetime of parts

Engine reassemble

Extension of operation from 6,000 to 30,000hrs

Boiler pipe replacement

Increase in pipe lifetime by 300% to 400%

SCR catalyst bed

Catalyst replacement cost savings by $10,000 to $1,000,000

Power reduction

From 75% to 98%

Oil exchange

Extension of exchange period from 500 to 2,500 hours

Schematic diagram of siloxanes removal process
biogas storage image

Biogas storage

dehydration image

Dehydration process

siloxanes image

Siloxanes removal process

dust removal image

Dust removal process

boiler engine image

Boiler engine generator

Swipe the screen to see more pictures.

Experimental Results

Hydrogen sulfide(H2S) removal capacity test

Hydrogen sulfide table
Item Unit DeHyS-200 DeHyS-250 Remarks
H2S removal capacity wt% Above 25 Above 30 Breakthrough Curve

Swipe the screen to see more tables.

Hydrogen sulfide removal test
hydrogen test image


Bed Volume(ml)




Retention Time(sec)


Space velocity(hr-1)


Breakthrough point


Effect of moisture
moisture graph
Effect of H2S concentration
inflow graph
Effect of space velocity
speed graph

Biogas Pretreatment Process Field Test: Result I

Busan Environmental Corp.
Busan corporation map image
Busan corporation image

Sewage treatment capacity


Food waste

1,300 ~ 1,400 ton/day

Biogas generation

23,000 m3/day

Hydrogen sulfide(H2S)

1,000 ~ 3,000 ppm


about 55 ㎎/m3

H2S effluent concentration & removal rate
breakthrough curve 1

Space velocity = 600hr-1

A comparison of breakthrough curves between DeHyS and A's product
breakthrough curve 2

Space velocity = 600hr-1

Before use
before use image


After use
after use image


Applications of biogas : City gas

Process gas concentration : H2S (1 ppm or less), Siloxanes(1 mg/m3 or less)

Sample location : The input and output tested

Field test conditions : 0.48 m3/hr, average H2S concentration(1,649 ppm), operating hours(136 hr)

H2S removal capacity : 28.67 wt%(Space velocity 600 hr-1 condition), A's product = 3.8 wt%

Siloxanes removal capacity : Incoming concentration 81 mg/m3, and removal rate 100% (after 120 hours)

Biogas Pretreatment Process Field Test: Result II

Gwangju 1st WWP
gwangju wwp map image
gwangju wwp image

Sewage treatment capacity


Sewage sludge and food waste

300 ~ 400 ton/day

Biogas generation

30,000 m3/day

Hydrogen sulfide(H2S)

about 2,500 ppm


about 60㎎/m3

Competitive Performance Comparison
comparison graph
Before use
before use image

(L) DeHyS / (R) Competitor A

After use
after use image

(L) DeHyS / (R) Competitor A

Applications of biogas : Boiler operation

Process gas concentration : H2S (1 ppm or less), Siloxanes (1 mg/m3 or less)

Sample location : The input and output testbed

Field test conditions : 0.18 m3/hr, average H2S concentration(2,355ppm), operating hours(138hr)

H2S removal capacity : 21.6 wt% (vs A's product = 6.9 wt%)

Siloxanes removal capacity : Incoming concentration 63 mg/m3, and removal rate 100%

Biogas Pretreatment Process Field Test: Result III

Incheon Environmental Corp. Seunggi branch
Incheon corporation map image
Incheon corporation image

Sewage treatment capacity


Biogas generation

8,000 m3/day

Hydrogen sulfide(H2S)

5,000 ppm


about 50 ㎎/m3

flow rate graph image

Removal rate according to H2S input/output

input image


testing image


bottom image


Applications of biogas : Manufacture of ultra-low sulfur components (0.5 ppm or less) for fuel cells(SOFC)

Process gas concentration : less than 0.5 ppm in H2S, not detected in siloxanes (confirmation of stable processing performance)

Sample location : The input and output testbed

Field test conditions : 3 m3/hr, average H2S concentration(4,722 ppm), operating hours(1,032 hr)

FS removal capacity : 26 wt% or over

Siloxanes removal capacity : about 5 wt% (space velocity 375 hr-1)

※ H2S and siloxanes removal rate : 99.99% or over (official test report attachment)

Biogas Pretreatment Process Field Test: Result Ⅳ

Hongcheon Eco-friendly Energy Town
Hongcheon town map image
Hongcheon town image

Sewage treatment capacity


Biogas generation

3,600 m3/day

Hydrogen sulfide(H2S)

about 1,500 ppm


about 5 ㎎/m3

flow rate graph
Hongcheon Biogas Field Test Picture & Graph
Hongcheon test graph image
field test image

Sample cyde : 0.5 hr or 1 hr

Sample location : Moisture removal tower at the rear of the digestive

Biogas flow method : down-stream

Applications of biogas : City gas production(less than H2S 5ppm)

Sample cycle : twice a day (average value application)

Sample location : The front and rear end of the desulfurization tower

Analysis method : Desulfurization tower-Portable hydrogen sulfide analyzer (Bio 5000), Rear end of desulfurization tower -NDIR(Automatic analysis)

Operation result : 3,600 m3/day, average H2S concentration(about 1,500ppm), usage period (8 months), March 2016 - currently in supply

When breakthroughing, removal capacity : 33wt%

Simultaneous removal of siloxanes