Odor Gas Emissions Treatment – RTO Regenerative Thermal Oxidizer

Odor Gas Treatment Solutions

We specialize in treating various odorous waste gases, including hydrogen sulfide, ammonia, and VOCs. We offer customized deodorization solutions such as biological filters, chemical scrubbing, activated carbon adsorption, and RTO/RCO, achieving high efficiency and compliance with standards. Our solutions are widely used in wastewater treatment plants, chemical plants, and the food industry.

 

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Sulfur Compounds
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Nitrogen Compounds
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Volatile Organic Acids
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Aldehydes and Ketones
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Aromatic Hydrocarbons & Heterocyclic Compounds

Odor Control: Reaching Standards From the Source

Odorous gases—such as hydrogen sulfide, ammonia, organic amines, and volatile organic compounds (VOCs)—not only emit pungent odors, severely impacting the lives of nearby residents, but may also contain toxic or even carcinogenic components. Long-term exposure can harm human health and damage the ecological environment. Traditional deodorization methods (such as spraying and adsorption) often only transfer pollution, failing to achieve a fundamental solution.

We specialize in deep odor gas treatment solutions centered around Waste Gas Incinerators. Through high-temperature oxidation (TO/RTO) or catalytic oxidation (CO/RCO) technologies, complex odor components are thoroughly decomposed into harmless substances such as CO₂ and H₂O, achieving a removal rate of over 99%. The system combines high reliability, low operating costs, and fully automated control, and has been successfully applied in various industries prone to odor generation, including chemical, pharmaceutical, waste treatment, and food processing.

Choosing our incineration solution is not only about meeting regulatory requirements such as the “Odor Pollutant Emission Standard” (GB 14554), but also a firm commitment to community responsibility and green manufacturing.

Major Components of Malodorous Gases

Gas Category Common Representative Substances Odor Characteristics Health Risks Summary
Sulfur Compounds Hydrogen Sulfide (H₂S), Methyl Mercaptan (CH₃SH), Dimethyl Sulfide (DMS), Dimethyl Disulfide (DMDS) Rotten eggs, decaying cabbage, garlic odor Highly toxic; even at low concentrations, it irritates eyes and nose; high concentrations can cause asphyxiation
Nitrogen Compounds Ammonia (NH₃), Trimethylamine (TMA), Indole, Skatole Pungent ammonia smell, fishy odor, fecal odor Irritates the respiratory system; long-term exposure affects the nervous system
Volatile Organic Acids Acetic acid, Propionic acid, Butyric acid, Valeric acid Sour, sweaty, putrid odors Corrosive; irritating to equipment and humans
Aldehydes and Ketones Formaldehyde, Acetaldehyde, Acrolein Sharp, pungent, rotten fruit odor Many are carcinogens or strong irritants
Aromatic Hydrocarbons &
Heterocyclic Compounds		 Styrene, Pyridine, Quinoline Medicinal, tar-like, bitter almond odor Some are carcinogenic or bioaccumulative

Note: In practice, malodorous gases often consist of a mixture of multiple substances with complex compositions and fluctuating concentrations. Tailored analysis is required to select appropriate treatment processes.

Common Sources of Odorous Gas

Industry/Facility Main Sources of Odor Typical Malodorous Components
Wastewater Treatment Plants Bar screens, grit chambers, sludge dewatering units, anaerobic tanks H₂S, NH₃, methyl mercaptan, organic acids
Waste Management Facilities Landfills, transfer stations, incineration plant unloading areas H₂S, NH₃, TMA, VFA (volatile fatty acids), DMS
Food Processing Industry Fish/meat processing plants, dairy factories, breweries (soy sauce, vinegar, alcoholic beverages) TMA (fishy odor), NH₃, organic acids, alcohols, esters
Livestock Farming Pig farms, chicken farms, cattle farms (manure treatment areas) NH₃, H₂S, indole, skatole, VFA
Chemical & Pharmaceutical Industry Synthesis workshops, solvent recovery, wastewater treatment plants Pyridine, benzene series, thiols, aldehydes, halogenated hydrocarbons
Pulp & Leather Industry Cooking black liquor, dehairing processes, wastewater treatment H₂S, NH₃, thiols, sulfides, organic amines
Biological Fermentation/Biogas Projects Anaerobic fermentation tanks, biogas liquid storage pools H₂S, NH₃, DMS, DMDS

Wastewater Treatment Plants

Waste Disposal Facilities

Food Processing

Livestock Farming

Chemicals & Pharmaceuticals

Paper & Leather

Biogas Engineering

Why Does Malodorous Waste Gas Require Professional Treatment?

Detectable at Trace Levels

Odorous compounds like hydrogen sulfide (H₂S) can be smelled at concentrations as low as 0.0005 ppm—far below health thresholds. Even compliant emissions may cause nuisance complaints and trigger “Not-In-My-Backyard” (NIMBY) opposition.

Toxic and Harmful to Health

Many odorous gases (e.g., H₂S, ammonia) irritate eyes and airways; others like formaldehyde and benzene are carcinogenic or mutagenic. Chronic exposure can lead to headaches, nausea, insomnia, and respiratory diseases.

Complex Mixtures, Hard to Treat

Odorous streams often contain multiple pollutants (e.g., H₂S + NH₃ + VOCs + organic acids) with fluctuating concentrations. Simple methods like scrubbing or carbon adsorption only mask odors temporarily and risk secondary waste (spent carbon, contaminated water).

Strict and Enforced Regulations

Global regulations now mandate odor control:

  • China: GB 14554 sets emission and boundary limits for 8 key odorants.
  • EU: IED requires Best Available Techniques (BAT).
  • California: AQMD enforces complaint response and reduction plans.

Non-compliance risks fines, production cuts, or shutdowns.

Our Core Technologies for Odorous Waste Gas Treatment

We offer a full range of advanced thermal and catalytic oxidation systems—engineered to destroy complex odorous compounds efficiently, reliably, and cost-effectively.

Regenerative Thermal Oxidizer (RTO)

  • Destroys odorous pollutants through high-temperature oxidation (typically 760–850°C).
  • Ideal for high-concentration, high-volume waste gas streams.

✔ 99% destruction efficiency

✔ Up to 95% thermal energy recovery

✔ Low auxiliary fuel consumption

Catalytic Oxidizer (CO)

  • Oxidizes odorous VOCs at lower temperatures using a catalyst (typically 250–400°C).
  • Best suited for low-to-medium concentration emissions with low particulate content.

✔ 30–50% lower operating temperature vs. thermal oxidizers

✔ Reduced natural gas usage and NOx formation

✔ Compact footprint

Thermal Oxidizer (TO)

  • Direct-flame combustion of contaminants at high temperatures (700–1,000°C).
  • Effective for high-concentration, non-recyclable, or halogenated waste gases.

✔ Simple, robust design with minimal maintenance

✔ Handles fluctuating loads and complex gas compositions

✔ Proven reliability in harsh industrial environments

Selective Catalytic Reduction (SCR)

  • Reduces nitrogen oxides (NOx) to N₂ and H₂O using ammonia/urea and a catalyst.
  • Essential for facilities emitting NOx-containing odorous gases (e.g., from high-temperature processes)

✔ 90% NOx removal efficiency

✔ Prevents secondary odor issues from NOx byproducts

✔ Compliant with stringent air quality standards

Regenerative Catalytic Oxidizer (RCO)

  • Combines catalytic oxidation with regenerative heat exchange for ultra-low energy use.
  • Optimized for medium-to-low concentration, high-volume streams (e.g., wastewater plants, food processing).

✔ Lowest operating costs among oxidation technologies

✔ Energy recovery >90%

✔ Quiet, stable operation with minimal emissions

Case Study –  Fish Canning Plant as an Example

I. Project Background and Exhaust Gas Conditions (Design Basis)

The main sources of malodorous gases in fish canning production include raw material thawing, pre-cooking/steaming, autoclave exhaust, and offal processing (fish meal).

Treated Airflow Rate: 45,000 Nm³/h(estimated to cover 3 production lines and the rendering facility).

Exhaust Gas Composition:

      • Odor Components: Trimethylamine (TMA, fishy smell), Hydrogen Sulfide (H2S, rotten egg smell), Mercaptans, Ammonia.

      • Physical Characteristics: Temperature 40-60℃, Relative Humidity >90%(saturated vapor), containing oil/grease mist.

Emission Standard: Required to meet stringent “No Odor at Property Line” standards (Odor Concentration < 500  OU).

II. Core Process Selection: 3rd Generation Rotary RTO

Selecting the 3rd Generation Circular Rotary RTO is crucial for this proposal. Compared to a traditional 3-tower RTO, it offers irreplaceable advantages in a fish canning environment:

  1. Zero Pressure Fluctuation: Traditional RTOs generate pressure pulses of up to ± 300  Pa  during valve switching, potentially causing back-puffing of odors into the plant. The Rotary RTO’s continuous distribution valve ensures pressure fluctuation is limited to ± 20 Pa , maintaining stable negative pressure for the workshop capture system, preventing odor leakage.

  2. Space Efficiency: The circular, integrated design typically requires only  60 % of the footprint of a traditional 3-tower RTO, suitable for congested food processing facilities.

Process Flow Diagram

Pre-treatment (De-oiling/De-watering/De-sulfurization) →3rd Generation Rotary RTO (Incineration/Oxidation) → Waste Heat Steam Boiler (Energy Recovery)→ Compliance Stack

III. Detailed System Design Scheme

1. Enhanced Pre-treatment System (The RTO’s “Protector”)

Fish oil and moisture are enemies of the rotary valve. If pre-treatment is inadequate, the valve seals will fail due to fouling within months.

  • Stage 1: Spray Scrubber Tower (Alkali + Hypochlorite)

    • Purpose: Chemical neutralization. Removes H2S(acidic) and Ammonia, while sodium hypochlorite oxidizes some of the most potent odorous compounds.

  • Stage 2: Wet Electrostatic Precipitator (WESP)

    • Key Configuration: A critical difference from standard RTO plans. Stainless steel collecting plates and high-voltage static electricity are used to remove micron-sized oil mist and water vapor from the airflow.

    • Target: Ensure the oil content entering the RTO is < 5 mg/m³.

2. RTO Unit Configuration (Referencing Rotary RTO Technology)

  • Model: R-RTO-450 (Rotary Type).

  • Ceramic Media: Use MLM (Multilayer Media) Ceramic Heat Storage Media, not standard bulk honeycomb ceramic.

    • Reason: MLM offers better anti-clogging properties and lower pressure drop, maintaining thermal recovery efficiency (TRE) stably above 96%.

  • Rotary Valve Purge: A dedicated 1:10 purge sector is designed, using clean air to flush residual untreated exhaust back into the combustion chamber, ensuring a Destruction Rate Efficiency (DRE) > 99.5%.

  • Material Upgrade: Due to the potential formation of trace SO2/SO3 from sulfur-containing exhaust, the furnace body contact surfaces must use 316L Stainless Steel lining and be coated with high-temperature anti-corrosion paint.

3. Waste Heat Recovery: Steam Generation (Most Economical Reuse)

Food processing plants are heavy steam consumers (autoclaves, cooking pots).

    • Equipment: Install a Smoke Tube Waste Heat Steam Boiler downstream of the RTO exhaust.

    • Conditions: RTO exhaust temperature is about 160℃ to 200℃  (high concentration).

    • Output: Heats 20℃  soft water to produce 0.5Mpa saturated steam, which is tied directly into the factory’s existing steam network.

IV. Projected Results and Data Analysis (Simulated Data)

The following data is based on industry projections, demonstrating the realistic performance of the upgraded system:

1. Pollutant Removal Performance

Pollutant Indicator Inlet Concentration (Pre-treatment Out) RTO Emission Concentration Removal Efficiency Result
Odor Unit (OU) 12,000 (Extremely High) < 300 > 97.5% Odor not perceptible at property line
Trimethylamine 45 mg/m³ < 0.2 mg/m³ > 99.5% Completely decomposed
Non-Methane Total Hydrocarbons 600 mg/m³ < 15 mg/m³ > 97% Exceeds most local standards

2. Energy Balance and Financial Benefits

Assuming the equipment operates 7,200 hours per year.

  • Natural Gas Consumption (Cost):

    • Due to 96% TRE and the heat released by VOC combustion, the RTO only needs minimal supplementary firing.

    • Average Natural Gas Consumption: Approx. 12m³/h.

    • Annual Cost (Assuming 3.5  RMB/m³): 12 ×3.5  RMB ×7200 ≈302,000 RMB.

  • Steam Recovery (Revenue/Savings):

    • Waste Heat Boiler Average Output: 0.8 tons/hour of steam.

    • Reference Industrial Steam Price: 220 RMB/ton.

    • Annual Revenue/Savings: 0.8 ×220 × 7200 = 1,267,200 RMB.

  • Electricity Consumption (Cost):

    • Increased power for the main fan and rotary motor: Approx. 55 kW.

    • Annual Electricity Cost (Assuming 0.8 RMB/kW): 55 × 0.8 RMB\×7200≈316,800 RMB.

3. Comprehensive Financial Summary

 

Annual Net Savings= Steam Revenue – (Gas Cost+ Electricity Cost)
1,267,200  RMB- (302,400  RMB + 316,800  RMB) = +648,000 RMB/year

Conclusion: While the initial investment for this RTO system (including the WESP pre-treatment) is high, the energy recovered annually means this environmental protection equipment generates approximately 648,000 RMB in energy savings each year, allowing the factory to recoup the equipment cost usually within 3-4 years.