SOx Gas Treatment Solutions | RTO Systems for DeSOx

Explore Ever-power Environmental’s DeSOx desulfurization equipment solutions for treating sulfur-containing waste gases. Achieve over 99% desulfurization efficiency, meeting China’s GB 16297-1996 standard, and suitable for the petrochemical industry. View case studies from Beijing and Shanghai, as well as regulations from neighboring countries such as Japan and South Korea, and the top 30 countries globally. Contact us now for customized services.

Kontaktujte nás

Z

SO₂

Z

CS₂

Z

H₂S

Z

Mercaptans

Z

Thioether

Sources & Environmental Challenges of SOx

In the petrochemical and refining industries, sulfur-containing gases primarily originate from FCC units, delayed coking, and hydrodesulfurization processes during crude oil processing. These gases, including hydrogen sulfide, mercaptans, and sulfur dioxide, can lead to acid rain formation and air pollution if left untreated. According to recent studies, global sulfur emissions have risen from low levels in 1750 to a peak in 2022, mainly due to industrialization. The necessity of treating these gases lies in protecting ecosystems and preventing soil acidification and water pollution. In China, in cities like Beijing and Shanghai, factory emissions directly impact air quality, leading to respiratory illnesses.
The history of sulfur-containing gases can be traced back to the Industrial Revolution, when coal burning caused the London smog incidents, prompting the earliest air pollution regulations. Today, with updated environmental regulations in 2025, treating sulfur-containing gases has become central to corporate compliance. Yuchang Environmental’s RTO system uses high-temperature oxidation to convert H2S into SO2, which is then neutralized through scrubbing, achieving efficient removal.

What is SOx?

SOₓ exhaust gas (sulfur oxide exhaust gas) refers to industrial or combustion emissions containing sulfur oxides, primarily sulfur dioxide (SO₂) and a small amount of sulfur trioxide (SO₃). In environmental engineering and air pollution control, SOₓ is commonly used as a general term for these pollutants.



Formation of acid rain

SO₂ is oxidized to SO₃ in the atmosphere, which then reacts with water to form sulfuric acid (H₂SO₄). Acid rain corrodes buildings, acidifies soil and water bodies, and damages ecosystems.



Zdravotní rizika

It irritates the respiratory tract, triggering coughs, asthma, and bronchitis; the sulfates formed by combining with particulate matter can penetrate deep into the alveoli, increasing the risk of cardiovascular disease.



Corrosion of equipment & materials

SO₂ and sulfuric acid mist are highly corrosive to metal pipes, boilers, chimneys, electronic equipment, etc., shortening their lifespan.



Impacts on Visibility and Climate

Sulfate aerosols are an important component of fine particulate matter (PM2.5) in the atmosphere, reducing atmospheric visibility (smog); They have a cooling effect (reflecting solar radiation)

SOx Emissions Analysis

Major Sources of SOx	Components of SOx	Special Characteristics
Fossil Fuel CombustionPower plants, industrial boilers using coal or oil	Sulfur Dioxide (SO₂)The predominant component	Acid Rain Precursor: Reacts with water vapor to form sulfuric acid (H₂SO₄), causing damage to forests, aquatic life, and building materials.
Průmyslové procesySmelting of mineral ores containing sulfur, oil refining	Sulfur Trioxide (SO₃)Usually forms secondary to SO₂	Respiratory Toxicity: Highly irritating to the respiratory system; triggers bronchoconstriction and asthma attacks even at low concentrations.
PřepravaLocomotives, ships, and heavy equipment using high-sulfur diesel	Sulfate Particles (SO₄^2-)Particulate form	PM2.5 Formation: Contributes significantly to the formation of fine particulate matter (secondary aerosols), reducing visibility and harming lung health.
Natural SourcesVolcanic eruptions, sea spray, biological decay in wetlands	Trace Sulfur Species	Cooling Effect: Sulfate aerosols can reflect sunlight (albedo effect), potentially causing a temporary local or global cooling effect on the climate.

Data Source: Environmental Science Reports | Last Updated: October 2023

Global SOx Emission Regulatory Landscape

China (National)

Baseline: GB 16297-1996 mandates <550 mg/m³.
Context: Founded on the Air Pollution Prevention Law.
Driver: Severe smog events catalyzed stricter legislative evolution.

China (Key Areas)

Guangdong: DB44/815 stricter limit at <100 mg/m³.
Beijing: DB11/447 emphasizes continuous monitoring (CEMS).
Shanghai: DB31/933 targets Chemical Industry Zones.

East Asia

Japan: Air Pollution Control Act enforces <100 mg/m³.
S. Korea: Clean Air Conservation Act baseline <500 ppm.
Focus: Stringent control on stationary industrial sources.

The Americas

USA: EPA NESHAP targets hazardous pollutants via federal mandates.
Brazil: CONAMA 382 defines max limits for fixed sources.
Goal: Reducing acid rain and health risks.

Europe & Eurasia

Germany: TA Luft sets the technical benchmark for air quality.
Russia: GOST standards ensure state-level compliance.
Trend: Broad adoption of Best Available Techniques (BAT).

ME & South Asia

Saudi Arabia: RCER regulations govern industrial cities.
India: CPCB sets national limits for high-pollution industries.
Challenge: Balancing industrial growth with clean air targets.

Our RTO for SOx Treatment (DeSOx)



Regenerative Thermal Oxidizer, RTO

Regenerative Thermal Oxidizer (RTO) is a highly efficient industrial waste gas treatment device that primarily converts organic pollutants into harmless carbon dioxide and water vapor through high-temperature oxidation. In the field of sulfur-containing gas treatment, RTOs are particularly suitable for industries such as petrochemicals, refineries, sulfur recovery units (SRUs), and fine chemicals. These gases often contain hydrogen sulfide (H₂S), sulfur dioxide (SO₂), or other sulfur compounds. RTOs can oxidize them into stable forms, but post-treatment (such as scrubbers) is necessary to prevent the emission of acidic gases. According to the latest research (such as EPA reports and industrial application cases), RTOs can achieve a heat recovery rate of over 95% and a destruction removal efficiency (DRE) of over 99% when treating sulfur-containing waste gases, but corrosion risks must be considered.



Working Principle of RTO

The working principle of an RTO is based on thermal oxidation: the sulfur-containing gases undergo oxidation reactions at combustion chamber temperatures of 800-1000°C. For example, H₂S can be oxidized to SO₂ or SO₃, which are then neutralized into sulfates through alkaline scrubbing. This makes RTOs the preferred technology for treating complex sulfur compounds, especially in the context of global environmental regulations (such as China’s GB 31571-2015 and the EU IED directive) requiring SOx emissions to be below 50 mg/Nm³.

RTO Process: Sulfur-Containing Gas Treatment

Integrated Workflow: Thermal Oxidation (DeVOC) + Wet Scrubbing (DeSOx)

1. Pre-Treatment Removes particulates to protect ceramic media.

2. RTO Oxidation H₂S converts to SO₂ at >850°C. 95% heat recovery.

3. DeSOx Polishing Caustic (NaOH) spray neutralizes acidic SO₂ into salt.

4. Discharge Final emission meets strict limits (< 50 mg/Nm³).

Technical Parameters of RTO

Category	Parametr	Value / Specification	Technical Note
1. Core Performance	Účinnost odstraňování	> 99%	For both SOx and VOCs
	Thermal Recovery	95% - 97%	Saves approx. 80% fuel
	Oxidation Temp	850 - 950°C	High temp ensures full S-conversion
	Doba pobytu	1 - 2 Seconds	Ensures complete oxidation reaction
	Airflow Range	10,000 - 500,000 m³/h	Scalable capacity
	Pokles tlaku	< 200 Pa	Low resistance design
	Turndown Ratio	5 : 1	Flexibility for load fluctuation
	System Availability	99%	High uptime reliability
2. Emission & Input	Inlet Sulfur Conc.	5,000 ppm H₂S	High sulfur tolerance
	Outlet SOx	< 50 mg/Nm³	Compliant with strict regulations
	Outlet NOx	< 100 mg/Nm³	Low NOx burner technology
	Kontrola pevných částic	Pre-filter System	Prevents media clogging
	Humidity Control	Pre-drying	Reduces moisture burden
	LEL Control Limit	< 25%	Lower Explosive Limit safety margin
	Outlet Temp	150 - 200°C	Safe discharge temperature
3. Design & Material	Construction Material	Hastelloy C-276	Critical: Anti-corrosion against H₂SO₄
	Výměník tepla	Structured Ceramic	High thermal mass media
	Surface Area	500 - 800 m²/m³	Specific surface area for heat transfer
	Chamber Volume	0.5 - 1 m³	Per 1,000 m³/h airflow
	Valve Switching	60 - 120 Seconds	Optimized cycle time
	Valve Cycle Life	> 1 Million Cycles	High durability switching valves
	Leakage Rate	< 0.1%	Poppet valve sealing technology
	System Footprint	10 - 50 m²	Compact design
4. Integration & Utility	Post-Treatment	DeSOx Scrubber	Critical: Removes SO₂ formed in RTO
	Typ paliva	Natural Gas	Low NOx burners utilized
	Spotřeba energie	0.5 - 1 kWh/m³	Low electrical demand
	Bake-out Temp	500°C	Self-cleaning mode for media
	Preheat Temp	200°C	Inlet waste heat utilization
	OPEX Savings	40%	Compared to standard thermal oxidizers
5. Control & Safety	Automation	PLC + AI Maint.	Smart predictive maintenance
	Monitorování	CEMS	Continuous Emission Monitoring System
	Safety Device	Flame Arrestor	Explosion prevention at inlet

Important Components & Consumables for RTO

Ventily

Hastelloy coating, lifespan 5-10 years; seals are consumables and need to be replaced annually.

Keramická média

High-alumina, acid-resistant; replaced every 5-7 years.

Hořák

Low NOx; nozzles are consumables and require quarterly inspection.

Fan

Drive belt, easily worn and replaced every 2 years.

Sensors

LEL temperature sensors, consumables requiring calibration every six months.

Scrubber packing

Plastic rings, replaced every 3 years due to fouling.

Comparison of RTOs From Major Brands



Dürr™'

Dürr™’s high-end rotary RTOs are known for their high heat recovery efficiency (typically around 98%), making them suitable for applications with extremely stringent energy efficiency requirements. However, their system cost is usually about 150% higher than standard solutions, making them more suitable for large projects with ample budgets and a focus on ultimate energy efficiency.



Anguil™

Anguil™ employs a modular design and performs robustly in handling exhaust gases containing sulfur or complex components. However, due to the longer customization process, the overall delivery time often takes 6–9 months or even longer, which may affect the project’s commissioning schedule.



Věčná síla

Ever-Power RTOs are positioned at the balance point between high performance and high responsiveness: we benchmark ourselves against international leading brands in core thermal efficiency (95–97% TER), corrosion-resistant structure, and intelligent control. At the same time, relying on our localized engineering team and flexible production lines, we achieve a total cost 30–40% lower than Dürr™ and a delivery time more than 40% faster than Anguil™. More importantly, we provide deep customization for each customer – not simply “selecting configurations” from a standard catalog, but designing and building an RTO specifically for you, based on your exhaust gas composition, process cycle, and site constraints.

Sharing Real Case Studies

Beijing Petrochemical Plant | 50,000 m³/h High-Volume Waste Gas

→ RTO + Sulfur-resistant design, 99% SOx removal rate, stable operation throughout the year, passed the ultra-low emission acceptance test in the Beijing-Tianjin-Hebei region.

Tokyo, Japan Precision Manufacturing Base | Strict Space Constraints + Complex Components

→ Seamless integration of RTO and FGD (flue gas desulfurization), fully compliant with Japan’s Air Pollution Control Act, and noise controlled below 65 dB – the neighbors thought we were just running air conditioners.

Seoul, South Korea Semiconductor Supporting Plant | H₂S concentration as high as 2000 ppm, so smelly that security guards had to wear gas masks

→ Customized two-stage oxidation + rapid cooling + adsorption post-treatment, outlet H₂S <10 ppm, employees can finally smoke near the exhaust port (although we don’t encourage it).

Střihač: Miya