A coke oven gas roots blower is a positive displacement industrial blower specially designed for pressurization, stable conveying and process supporting of purified coke oven gas (COG). As core gas handling equipment in coking plants, the coke oven gas roots blower features constant flow, stable pressure output and speed-linear flow adjustment, which perfectly matches the variable working conditions of coke oven gas recovery and utilization systems.
Different from centrifugal blowers applied for raw coke oven gas primary transportation, the coke oven gas roots blower is widely used in medium and small coking factories for purified COG pressurization. It handles clean coke oven gas composed of hydrogen, methane and trace corrosive components, supporting multiple downstream industrial applications including furnace reheating, power generation, hydrogen production and methanol synthesis.
3. Core Industrial Applications of Coke Oven Gas Roots Blower in Coking Plants
3.1 Coke Oven Gas Roots Blower for Purified COG Pressurized Conveying (Core Usage)
The standard COG process flow is: Raw coke oven gas → Primary cooler → Electrostatic tar precipitator → Desulfurization → Benzene removal → COG roots blower → End-user pipeline network.
The coke oven gas roots blower stably boosts low-pressure purified COG (2-5kPa inlet pressure) to 30-80kPa, overcoming pipeline and system resistance for long-distance and stable gas delivery. The pressurized gas is mainly supplied for three industrial scenarios: coke oven self-heating, industrial boiler and gas turbine power generation, and deep chemical processing such as COG-to-hydrogen and COG-to-LNG production.
3.2 COG Roots Blower for COG Fine Desulfurization Process Pressurization
In the COG fine desulfurization and hydrolysis process, the roots blower provides continuous and stable system pressure to push coke oven gas through catalytic adsorption towers, heat exchangers and filter devices. The equipment produces a 12-20℃ gas temperature rise during pressurization, which effectively reduces the heat load of subsequent heat exchange equipment and improves the overall operation efficiency of the desulfurization system.
3.3 Coke Oven Gas Roots Blower for Gas Holder Back-End External Gas Supply
Coke oven gas holders stabilize pipeline gas pressure and balance gas supply fluctuations. The matched coke oven gas roots blower unit further pressurizes buffered COG for external grid transmission. Most coking plants adopt one-use-one-standby blower configuration with frequency conversion adjustment and large-circulation bypass pressure control, effectively preventing pipeline overpressure and gas backfire, ensuring safe and continuous external gas supply.
3.4 Limited Application: Coke Oven Gas Roots Blower for Negative Pressure COG Extraction
Roots vacuum blowers can realize negative pressure gas extraction for special small-scale COG processes. However, raw coke oven gas with high tar and naphthalene content is strictly prohibited from directly entering the COG roots blower. Unpurified tar and naphthalene will adhere to rotor gaps, causing equipment jamming, overheating and severe wear. Negative pressure extraction is only applicable for fully pre-treated clean COG.
4. Specialized Design Requirements for Coke Oven Gas Roots Blower (COG Working Condition)
Coke oven gas is flammable, explosive and slightly corrosive, so industrial roots blower for COG service requires customized anti-leakage, explosion-proof and anti-corrosion design, different from ordinary air blowers.
4.1 Professional Sealing System for Coke Oven Gas Roots Blower
Equipped with dual mechanical seals and nitrogen isolation purging systems, the blower isolates flammable COG from external air. Continuous low-pressure nitrogen purging prevents gas leakage and air infiltration, avoiding the formation of explosive mixed gas inside the equipment, which is the core safety design for coke oven gas roots blower.
4.2 Explosion-Proof Configuration Standards for COG Roots Blower
The motor and on-site control box comply with Ex d IIB T4 explosion-proof grade. The whole machine is equipped with anti-static grounding devices to eliminate static spark risks, meeting the strict safety standards of coking plant explosive environments.
4.3 Anti-Corrosion Material Selection for Coke Oven Gas Roots Blower
For conventional low-sulfur COG working conditions, HT250 cast iron is adopted for the blower shell. For high-hydrogen-sulfide COG environments, 304/316 stainless steel is used for flow-through parts, matched with fluororubber and PTFE corrosion-resistant seals to extend equipment service life.
4.4 Essential Safety Accessories for COG Roots Blower Stable Operation
Standard configuration includes overpressure relief valve, inlet precision filter, gas detection alarm, temperature and vibration online monitoring device, and import/export check valves. These accessories effectively prevent pipeline blockage overpressure, gas backflow and backfire faults, ensuring long-term stable operation of the COG roots blower.
5. Standard Operating Parameters of Industrial Coke Oven Gas Roots Blower
Medium: Purified coke oven gas Inlet pressure: 2-6kPa Pressure rise: 49-58.8kPa Inlet temperature: 25-45℃ Outlet temperature rise: 12-20℃ Flow range: 5-120 m³/min Sealing mode: Dual mechanical seal + nitrogen purging
6. Common Faults & Solutions for Coke Oven Gas Roots Blower Operation
6.1 Rotor Blockage & Adhesion of COG Roots Blower
Trace naphthalene and tar in purified COG will crystallize and adhere to rotors after temperature drop. Regular low-temperature steam cleaning (≤70℃) is required to remove scale and avoid equipment jamming.
6.2 Over-Temperature Failure of Coke Oven Gas Roots Blower
High pressure rise will cause rapid temperature increase. The outlet temperature of coke oven gas roots blower must be controlled below 130℃ to prevent seal aging and explosive safety hazards.
6.3 Nitrogen Seal Failure Risk of COG Roots Blower
Nitrogen purging system failure must trigger interlock shutdown to prevent COG leakage and air back suction, eliminating explosion risks.
7. Coke Oven Gas Roots Blower vs Screw Blower vs Centrifugal Blower | Selection Guide
For COG coking processes, equipment selection depends on flow rate, pressure and gas cleanliness, and the comparison of roots blower vs screw blower and centrifugal blower is as follows:
7.1 Performance & Advantages of Coke Oven Gas Roots Blower
Positive displacement structure, constant flow and stable pressure output, low speed linear regulation. Suitable for medium and small flow, variable pressure working conditions and purified COG pressurization. It is the most cost-effective equipment for conventional coking plant gas conveying.
7.2 Roots Blower vs Screw Blower for COG Applications
Higher efficiency and lower noise than traditional roots blower, with better energy-saving performance. Suitable for large-flow, long-term continuous COG operation, but with higher equipment and maintenance costs.
7.3 Roots Blower vs Centrifugal Blower for Coke Oven Gas Handling
Mainly used for raw coke oven gas primary transportation. It has strong impurity resistance and large flow capacity, but poor pressure stability, not suitable for fine pressurization of purified COG.
8. Final Verdict: Value of Coke Oven Gas Roots Blower for Coking Industry
The coke oven gas roots blower / COG roots blower is indispensable core equipment in purified coke oven gas recovery and utilization systems. With stable pressure output, flexible flow adjustment and high safety performance, it covers desulfurization pressurization, gas conveying and external gas supply working conditions in coking industry. Compared in the roots blower vs screw blower system, roots blowers occupy mainstream market share in medium and small coking projects due to high cost performance and reliable operation.
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