Comparison of Three Exhaust Gas VOCs Treatment Processes for Packaging Printing Plants: RTO / RCO / Activated Carbon—A Realistic Overview of Equipment Investment and Operation & Maintenance Costs for the Three Systems

In September 2024, a packaging printing customer in Jiangsu (a mid-to-large printing plant with 80 employees and an annual output value of 60 million) received a rectification notice from the local ecology and environment bureau: “Your VOCs emission concentration is 80 mg/m³, exceeding the emission standard (50 mg/m³). Treatment must be completed and the emissions brought into compliance within 30 days; otherwise, production will be suspended.”

A customer urgently contacted us for advice: “We researched 3 environmental protection equipment companies. Company A recommended RTO, Company B recommended RCO, and Company C recommended activated carbon. The quotations for the three options are 3.8 million, 2.2 million, and 600,000, respectively. Which option should we choose?”

I asked the client to send over the proposals from three companies. Company A’s RTO solution was designed for an airflow rate of 8000 m³/h (the printing plant actually requires only 4000 m³/h), Company B’s RCO solution was designed for an airflow rate of 5000 m³/h (a close match), and Company C’s activated carbon solution was designed for an airflow rate of 4000 m³/h (a match, but it overlooked the cost of activated carbon replacement).

I said, "Don't rush into making a selection. First, find out the printer's 3 core data points: 1) actual VOCs air volume (m³/h); 2) VOCs concentration (mg/m³); and 3) daily operating hours (hours). These 3 data points determine which process you should choose—not the price.

The customer replied: "I don't know much about this. Please help me find a reliable eco-friendly company to conduct an assessment."

I found a third-party environmental consulting company to conduct an assessment for him. Two weeks later, the assessment report was issued: the customer’s printing plant actually has a VOCs airflow rate of 3500 m³/h and a VOCs concentration of 150 mg/m³, with 12 hours of daily operation. Based on these data, the RTO equipment is quoted at 2.8 million (designed for 4000 m³/h), the RCO equipment at 1.8 million (designed for 4000 m³/h), and the activated carbon system at 500,000 (designed for 4000 m³/h).

The customer ultimately selected the RCO solution, investing 1.8 million and completing installation and commissioning in 2 months. VOCs emission concentrations stabilized at 15-20 mg/m³, well below the 50 mg/m³ standard, and the rectification passed.

This is the most common real-world scenario in VOCs treatment for packaging printing plants: customers are overwhelmed by quotes from multiple environmental protection companies, do not know which process to choose, and ultimately select based on price, resulting in a solution that does not suit the printing plant’s actual operating conditions.

The Real Investment and Operating Costs of the Three Processes

Category 1: RTO (Regenerative Thermal Oxidation)

RTO (Regenerative Thermal Oxidizer) breaks down VOCs into CO₂ and H₂O through high-temperature oxidation (760-850℃). RTO equipment has a heat-exchange efficiency of 90-95% and a treatment efficiency of over 99%.

Investment cost (at an airflow of 4000 m³/h): equipment: 200-280 × 10,000 yuan + installation: 30-50 × 10,000 yuan + duct modification: 20-40 × 10,000 yuan + electrical cabinet and controls: 20-30 × 10,000 yuan; total investment: 270-400 × 10,000 yuan.

Operating and maintenance costs (based on 300 operating days per year, 12 hours per day): natural gas consumption of 500,000-800,000 per year (calculated at a natural gas price of 2.5 yuan/m³) + electricity costs of 150,000-250,000 per year + equipment maintenance costs of 100,000-150,000 per year + heat storage medium replacement costs (once every 5 years) of 300,000-500,000 per year (allocated on an annual basis), for total annual operating and maintenance costs of approximately 800,000-1.3 million.

Applicable scenarios: Large printing plants with VOCs concentrations ≥ 1000 mg/m³ (high concentration and high air volume), operating ≥ 16 hours per day, and an annual output value ≥ 1 billion. RTO consumes substantial natural gas, so when VOCs concentrations are low, its operating costs are actually higher than those of RCO.

Type II: RCO (Regenerative Catalytic Oxidation)

RCO (Regenerative Catalytic Oxidizer) uses a catalyst to decompose VOCs at 300-500℃. RCO equipment has a heat exchange efficiency of 85-90% and a treatment efficiency of 95-98%.

Investment cost (at an airflow of 4000 m³/h): equipment body 1.3-1.8 million + installation costs 250,000-400,000 + pipeline modifications 200,000-400,000 + electrical cabinet and control system 150,000-250,000, for a total investment of 1.9-2.85 million.

Operating and maintenance costs (based on 300 operating days per year, 12 hours per day): natural gas consumption of 250,000–400,000 per year (calculated at a natural gas price of 2.5 yuan/m³, with the catalyst lowering the reaction temperature) + electricity costs of 120,000–200,000 per year + equipment maintenance costs of 80,000–120,000 per year + catalyst replacement costs (once every 3–5 years) of 150,000–250,000 per year (allocated), with annual operating and maintenance costs of approximately 500,000–800,000.

Applicable scenarios: VOCs concentration of 100-1000 mg/m³ (medium concentration), operation for 8-16 hours per day, and medium-to-large printing plants with an annual output value of RMB 50 million to 100 million. RCO is the mainstream choice for small and medium-sized printing plants, offering the best value for money.

Type Three: Activated Carbon Adsorption

Activated carbon adsorption (Activated Carbon Adsorption) removes VOCs through the porous structure of activated carbon. Treatment efficiency is 70-90% (depending on activated carbon quality and the type of VOCs), and the activated carbon must be replaced regularly.

Investment Costs (at an airflow of 4000 m³/h): equipment 300,000–500,000 + installation 50,000–100,000 + duct modifications 100,000–200,000 + electrical cabinet and controls 50,000–100,000, for a total investment of 500,000–900,000.

Operating and maintenance costs (based on 300 operating days per year, 12 hours per day): activated carbon replacement (once every 1-3 months) 300,000-600,000/year + electricity costs 80,000-150,000/year + equipment maintenance 30,000-50,000/year + spent activated carbon disposal (hazardous waste) 50,000-100,000/year. Total annual operating and maintenance costs are approximately 500,000-900,000.

Application Scenarios: Small and medium-sized printing plants with VOC concentrations ≤ 100 mg/m³ (low concentration), operating ≤ 8 hours per day, and an annual output value ≤ 30 million. Activated carbon adsorption has low initial investment but high operating and maintenance costs, making it suitable for short-term remediation or printing plants with limited budgets.

The 3 Selection Questions Every Printing Factory Owner Should Ask

Question 1: What are the actual airflow rate, concentration, and operating hours of VOCs at my printing plant?

Before selecting a system, the printing plant must determine 3 core data points: 1) VOCs airflow rate (m³/h), determined by workshop air changes per hour × workshop volume; the airflow rate in a typical printing plant workshop is 2000-8000 m³/h; 2) VOCs concentration (mg/m³), determined by the printing process, ink type, and printing area; the concentration in a typical printing plant is 50-500 mg/m³; 3) daily operating time (hours), determined by order saturation; the typical operating time of a printing plant is 8-16 hours.

The most important question for a printing plant owner is: “Environmental protection company, is the solution you developed based on my actual operating conditions (air volume / concentration / duration), or is it simply a generic industry solution?” If the environmental protection company cannot clearly explain the printing plant’s actual operating conditions, the solution may not be suitable.

Question 2: Can my printing plant receive subsidies for VOCs pollution control?

The "VOCs Control Implementation Plan" jointly issued by the National Development and Reform Commission and the Ministry of Ecology and Environment in 2024 specifies that central and local governments shall provide equipment subsidies of 30-50%, capped at 1-2 million, to small and medium-sized printing plants that adopt high-efficiency treatment processes such as RTO / RCO.

The most important question for a printing plant owner to ask is: “Environmental protection companies, can your solution help me apply for a VOCs treatment subsidy? If so, approximately how much is the subsidy? If not, can you help me find a third-party consulting company to apply for it?”

Real case: A printing plant in Jiangsu selected the RCO solution with a total investment of 2.2 million yuan and obtained provincial subsidies of 800,000 yuan and municipal subsidies of 400,000 yuan through a third-party consulting company, resulting in an actual net investment of 1 million yuan. The subsidy application process takes 3-6 months.

Question 3: What is your expected order growth over the next 5 years?

RTO / RCO equipment is typically designed with a capacity margin of "current air volume × 1.5-2." If the printing plant's orders are expected to grow by more than 50% within 5 years, equipment should be selected based on the projected air volume after growth; if orders remain stable over the next 5 years, equipment may be selected based on the current air volume.

The most important question for a printing plant owner to ask is: “Environmental protection company, how much design margin is built into the solution you’ve proposed for me? If orders increase by 50% within 5 years, will this equipment still be usable? What modules will need to be added?”

5 Real-World Implementation Differences Across the 3 Types of Equipment

Difference 1: Floor Area

The RTO equipment occupies an area of approximately 60-100 m² (equipment body + thermal storage chamber + control room) and requires a dedicated equipment room or outdoor site.

RCO equipment occupies an area of approximately 40-70 m², which is 30-40% smaller than RTO.

The activated carbon equipment occupies an area of approximately 15-30 m² and can be placed in a corner of the workshop or outdoors.

The most important question for a printing plant owner is: “Does my printing plant have 60 m² of space for installing equipment? If not, I recommend choosing RCO or activated carbon.”

Difference 2: Approval Difficulty

RTO equipment requires an environmental impact assessment report (EIA report). The approval period is 3-6 months, and the approval cost is 150,000-300,000.

RCO equipment requires an Environmental Impact Assessment Report Form (EIA report form). The approval cycle is 1-3 months, and the approval fee is RMB 8-15 ten-thousand yuan.

Activated carbon equipment requires an Environmental Impact Assessment Registration Form. The approval process takes 7-15 days and costs RMB 1-3 ten thousand.

The most important question for a printing plant owner is: “At what stage are my printing plant’s environmental impact assessment procedures? If they are not complete, consider activated carbon (fastest approval).”

Difference 3: Natural Gas Dependency

RTO equipment must be connected to a natural gas pipeline (if no pipeline is available, an LNG gasification station needs to be built, requiring an additional investment of 1-2 million).

RCO equipment can use natural gas or electric heating (the electric heating version costs 200,000–300,000 more but does not require a natural gas pipeline).

The activated carbon equipment requires neither natural gas nor electric heating; it only requires fans and ductwork.

The most important question for a printing plant owner is: “Does my printing plant have a natural gas pipeline? If not, I recommend choosing the activated carbon or RCO electric heating version.”

Difference 4: Consistency in Meeting Standards

RTO equipment treatment efficiency exceeds 99%, with VOCs emissions consistently maintained at 10-20 mg/m³, well below the 50 mg/m³ standard.

RCO equipment treatment efficiency is 95-98%, with VOC emissions consistently maintained at 15-30 mg/m³. This complies with the 50 mg/m³ standard, although the margin is relatively limited.

The activated carbon equipment has a treatment efficiency of 70-90%, with VOCs emissions stably maintained at 30-50 mg/m³. As this approaches the 50 mg/m³ standard, the activated carbon must be replaced frequently.

The most important question for a printing plant owner to ask is: “Are the emission standards in the area where my printing plant is located 50 mg/m³ or 30 mg/m³? If they are 30 mg/m³, choose RTO or RCO rather than activated carbon.”

Difference 5: Hazardous Waste Generation

RTO equipment does not generate hazardous waste (VOCs are decomposed into CO₂ and H₂O).

RCO equipment generates a small amount of spent catalyst (replaced every 3-5 years, approximately 1-2 tons each time, with hazardous waste disposal costs of 2-4 ten-thousand yuan/ton).

Activated carbon equipment generates a large amount of spent activated carbon (replaced every 1-3 months, approximately 2-5 tons per replacement, at a hazardous waste disposal cost of 1.5-3 ten thousand yuan per ton).

The most important question for a printing plant owner is: “How capable is my printing plant’s hazardous waste treatment operation? What is the quote from the hazardous waste treatment company? If hazardous waste treatment costs are high, consider choosing RTO or RCO.”

Real-World Implementation Cost Comparison for 3 Types of Equipment (Based on 4000 m³/h Airflow, 300 days/year, 12 hours of Operation per Day)

Equipment type | Investment | Annual O&M | 5-year total cost | 5-year net cost (including a subsidy of 1 million)

RTO | 3.5 million | 1.05 million / year | 3.5 + 5.25 = 8.75 million | 7.75 million

RCO | 2.2 million | 650,000 / year | 2.2 + 3.25 = 5.45 million | 4.45 million

Activated carbon | 600,000 | 700,000 / year | 600,000 + 3.5 million = 4.1 million | 3.1 million

Cost comparison: Activated carbon has the lowest 5-year net cost (310 × 10,000 RMB), but it must be replaced frequently (1-3 times per month), resulting in high operation and maintenance costs and poor consistency in meeting emission standards. RCO has a mid-range 5-year net cost (445 × 10,000 RMB), offers simple operation and maintenance, and provides consistently reliable emission compliance, making it the mainstream choice for small and medium-sized printing plants. RTO has the highest 5-year net cost (775 × 10,000 RMB), but it offers the simplest operation and maintenance and the most stable emission compliance, making it suitable for large printing plants.

The One Thing a Printing Plant Owner Should Say Most

“VOC treatment is not simply a matter of installing one piece of equipment. It requires selecting among 3 types of processes (RTO / RCO / activated carbon) based on the printing plant’s actual operating conditions. I suggest that you first provide me with 3 data points from the printing plant (air volume / concentration / treatment duration), and I can prepare a ‘operating conditions + process matching list’ for you to use as the basis for equipment selection. If all you have is the statement that the printing plant needs VOC treatment, with no specific data, I recommend consulting a third-party environmental consultancy for an assessment first to avoid selecting the wrong process.”

After hearing this explanation, the customer will understand the true cost of VOCs treatment (equipment investment + operation and maintenance + hazardous waste + subsidy application), reducing the likelihood of disputes arising later due to selecting the wrong process.

Lessons from a Print Shop Owner's Real Financial Accounts

Further Reading

For the actual disposal price differences of three types of printing waste liquid from packaging printing plants, see Actual Disposal Price Differences of Three Types of Printing Waste Liquid. For the actual list of five types of hazardous waste from packaging printing plants, see Actual List of Five Types of Hazardous Waste from Packaging Printing Plants. For three key occupational health indicators for packaging printing plants (VOC / noise / dust), see Three Key Occupational Health Indicators for Packaging Printing Plants.