Two-Stage Heat Exchange CO Oxidation Furnace

Defaee Two-Stage Heat Exchange CO Oxidation Furnace is a high-performance integrated environmental protection and energy-saving equipment, integrating CO catalytic oxidation, two-stage high-efficiency heat recovery, low-pressure natural gas combustion and intelligent control technology. It is widely deployed for CO-containing industrial exhaust gas purification and waste heat recovery systems in metallurgy, chemical, building materials and other industries.

Using natural gas as a low-pressure heat source, the equipment recovers waste heat from high-temperature flue gas step by step through a two-stage plate heat exchange structure, realizing harmless treatment of CO exhaust gas and efficient utilization of thermal energy simultaneously. With core advantages of environmental compliance, energy consumption reduction and stable operation, it is a mainstream solution for comprehensive industrial exhaust gas treatment.

Core Operating Principle

1 CO Catalytic Oxidation

After pre-treatment (dust removal and fire arresting), CO-containing industrial exhaust gas enters the furnace reaction chamber. With noble metal catalysts (platinum, palladium), catalytic oxidation reaction occurs at a low temperature of 450-480℃, converting toxic CO into non-toxic CO₂.

Reaction formula: 2CO + O₂ → 2CO₂ (catalyst, 450-480℃)

This flameless process features high safety, and can simultaneously decompose trace VOCs in exhaust gas to meet national environmental emission requirements.

2 Two-Stage Heat Exchange

The built-in two-stage plate heat exchangers adopt a graded cooling, gradient heat exchange design to maximize waste heat recovery from post-reaction high-temperature flue gas:

1. First-stage heat exchange: 480℃ high-temperature flue gas enters the first-stage plate heat exchanger, exchanging heat countercurrently with low-temperature inlet exhaust gas. The flue gas temperature drops to 240-260℃, while the inlet gas is preheated to 200-220℃, reducing subsequent natural gas heating energy consumption.

2. Second-stage heat exchange: The pre-cooled flue gas enters the second-stage heat exchanger, exchanging heat with fresh air or low-temperature medium further. The flue gas temperature drops below 120℃, and the waste heat recovery rate reaches over 75%, far higher than single-stage heat exchange.

3. Temperature regulation: After heat exchange, three sets of air dampers precisely adjust the flue gas to stabilize the discharge temperature at around 80℃, avoiding equipment failure or thermal pollution caused by excessive temperature.

3 Low-Pressure Natural Gas Combustion

The equipment is equipped with a low-pressure natural gas combustion system, with gas supply pressure controlled at 0.02-0.05MPa to adapt to industrial low-pressure gas conditions. After precise proportioning through a pressure reducing valve, filter and flow meter, natural gas enters the burner and fully mixes with combustion air, burning at low temperature in the furnace to provide stable heat for the catalytic reaction.

The low-pressure combustion design eliminates safety risks of high-pressure combustion, with a combustion efficiency of over 99%. NOₓ and CO emission concentrations in flue gas are far below national standards, and operating cost is 30%-40% lower than electric heating solutions.

Core Equipment Structure

1 Furnace Assembly

The furnace adopts a double-layer structure of high-temperature resistant carbon steel + aluminum silicate insulation layer. The inner layer withstands 600℃, and the outer surface temperature is ≤50℃ to minimize heat loss. The furnace is divided into five sections: inlet section, preheating section, catalytic reaction section, two-stage heat exchange section and exhaust section. It is integrally welded with good sealing performance, and equipped with a built-in pressure relief port for automatic overpressure protection.

2 Two-Stage Heat Exchange Module

The core consists of two stages of high-efficiency plate heat exchangers made of 304 stainless steel, with high temperature resistance, corrosion resistance and excellent heat transfer performance. The two-stage heat exchangers are arranged in series with guide plates in the middle to ensure uniform flue gas flow. Optimized plate spacing reduces flue gas resistance and fan energy consumption, and the module is easy to disassemble and clean for dusty exhaust gas conditions.

3 Low-Pressure Natural Gas Combustion System

It consists of natural gas pipeline, low-pressure pressure reducing valve, gas filter, flow regulating valve, burner, ignition device and flame detector. The pressure reducing valve stabilizes gas pressure at 0.02-0.05MPa, and the flow valve precisely controls gas supply. The porous injection burner ensures full mixing of gas and air. The automatic ignition device and real-time flame detector cut off gas supply automatically in case of flameout to prevent leakage.

4 Catalytic Reaction System

It includes a catalyst bed with honeycomb ceramic substrate loaded with platinum-palladium noble metal catalysts, featuring anti-poisoning, high temperature resistance and 2-3 years of service life. At least 5 temperature sensors are installed in the furnace to monitor key temperature points in real time, precisely controlling the reaction temperature at 450-480℃ and ensuring CO conversion rate ≥99%.

5 Intelligent Control System

Adopting PLC (Programmable Logic Controller) with touch screen operation, it integrates temperature control, pressure monitoring, gas interlock, fault alarm and data recording functions. It supports fully automatic operation, one-key start/stop, and automatic adjustment of gas flow and damper opening. It monitors pressure difference, gas pressure and flame status in real time, with automatic alarm and shutdown for abnormalities, and supports remote monitoring and data upload.

6 Safety Auxiliary System

· Fire arrestors and dust collectors at both inlet and outlet isolate production lines from treatment equipment and intercept dust to prevent backfire and clogging.

· Pressure relief port with explosion-proof membrane on the top of the reaction chamber automatically relieves pressure in case of overpressure.

· Reliable grounding of the metal shell with grounding resistance ≤4Ω prevents static accumulation and electric shock accidents.

Key Performance Advantages

1 High-Efficiency Purification & Compliant Emission

CO catalytic conversion rate reaches ≥99%, with CO emission concentration ≤50mg/m³ and simultaneous VOCs removal, complying with the national air pollutant emission standard for industrial furnaces. Low-pressure natural gas combustion ensures NOₓ emission ≤100mg/m³, with no black smoke or peculiar smell.

2 High Waste Heat Recovery Rate & Remarkable Energy Saving

The two-stage plate heat exchange structure achieves a waste heat recovery rate of ≥75%, reducing natural gas consumption by 20%-25% compared with single-stage heat exchange. Flue gas discharge temperature is ≤120℃, and recovered waste heat can be used for inlet preheating, hot water supply or heating, realizing cascade energy utilization.

3 Low-Pressure Operation & High Reliability

Low-pressure gas combustion (0.02-0.05MPa) eliminates high-pressure leakage risks. Multiple safety interlocks (flameout, over-temperature, over-pressure, grounding protection) provide full-process safety protection. The redundant two-stage heat exchange design ensures continuous operation even if one stage fails.

4 Intelligent Control & Low Maintenance

Fully automatic PLC control requires no on-duty personnel with simple operation. Real-time parameter display and automatic fault alarm enable quick troubleshooting. The detachable heat exchanger and easy-to-replace catalyst reduce maintenance costs, with an overall equipment service life of 10-15 years.

5 Strong Adaptability & Wide Application

It treats industrial exhaust gas with 0.5%-5% CO concentration and 100-300℃ temperature, adapting to blast furnace exhaust, chemical synthesis exhaust, kiln exhaust and other working conditions. It matches conventional industrial low-pressure gas pipelines without extra high-pressure transformation.

Technical Specifications (Standard Model)

Installation & Commissioning Guidelines

1 Installation Requirements

1. Install on flat concrete ground with foundation bearing capacity ≥5t/m², and reserve ≥1.5m maintenance space around.

2. Natural gas pipelines adopt seamless steel pipes with welded connections, and shall pass an air tightness test (0.1MPa, 30min no leakage).

3. Reliable equipment grounding with ≥4mm² yellow-green grounding wire, grounding resistance ≤4Ω.

4. Flexible connections at inlet and outlet pipelines to avoid vibration damage.

5. Install differential pressure gauges at heat exchanger inlets and outlets to monitor clogging.

2 Commissioning Procedures

1. No-load commissioning: Power on, start the fan and control system, verify normal operation and accurate parameter display.

2. Gas commissioning: Introduce natural gas for low-pressure debugging, confirm no pipeline leakage, normal ignition and stable flame.

3. Load commissioning: Introduce CO-containing exhaust gas, gradually adjust gas flow and dampers to stabilize reaction temperature at 450-480℃, and run continuously for 24h after emission reaches the standard.

4. Interlock commissioning: Simulate flameout, over-temperature and over-pressure faults to verify alarm and shutdown functions.

Routine Maintenance

· Daily: Check gas pressure, flame status, furnace temperature, pressure difference and grounding, and record operation data.

· Weekly: Clean the gas filter and fire arrestor, check damper flexibility, and tighten connecting bolts.

· Monthly: Inspect the catalyst bed, clean surface dust, and clean heat exchanger plates to prevent clogging.

· Annually: Comprehensively inspect insulation, heat exchanger, burner and control system, replace aging components, and calibrate sensors.

· Long-term shutdown: Close gas valves, drain pipeline gas, protect the equipment from dust, and ventilate regularly to prevent moisture corrosion.

Applications & Value

This equipment is widely used for CO exhaust gas purification in metallurgical blast furnaces, chemical synthesis processes, building material kilns and machinery heat treatment. It delivers comprehensive value: it achieves harmless exhaust gas treatment for environmental compliance, reduces operating costs through high-efficiency waste heat recovery, ensures production safety with multiple protection mechanisms, and achieves investment payback within 1-2 years through recovered heat revenue, providing a win-win solution of environmental protection and energy saving for industrial enterprises.