RTO Waste Gas Treatment for Beijing Oriental Petrochemical Relocation & Renovation Project
Project Overview
This project is a key relocation and renovation project of Beijing Oriental Petrochemical. It centrally treats mixed volatile organic compound (VOC) waste gas generated from VAC process units, tank truck loading/unloading vents, EVA silo ventilation air, PVA production exhaust and acetic acid tank farm exhaust. The waste gas contains ethylene, vinyl acetate, methanol, acetaldehyde and other organic substances, featuring both continuous and intermittent discharge conditions. The system requires outstanding stability, strict dioxin control and high operational safety. The designed annual operating hours reach 8,000 hours, with an operational load flexibility ranging from 0% to 110%.
Core Parameters
- Total gas treatment capacity: 29,000 Nm³/h
- Maximum VOC concentration: 7997.7 ppm-v
- Average calorific value of waste gas: 5987.0 kcal/kg
Process Solution
A three-chamber regenerative thermal oxidizer (RTO) system is adopted, with a full positive pressure design to adapt to pressure differences of multiple waste gas streams.
Process Flow: Waste Gas → Buffer Gas-Liquid Separator → Baghouse Dust Collector → Main Fan → Three-Chamber RTO → Secondary Combustion Chamber → High-Altitude Discharge
Pretreatment: The buffer tank realizes gas-liquid separation, and the bag filter intercepts dust and liquid droplets to protect the subsequent furnace body and valves.
Main Combustion: The switching cycle of RTO is 90~120 seconds. The combustion chamber maintains a temperature of 800~850℃, and the flue gas residence time is longer than 0.8 seconds to fully decompose VOC pollutants.
Dioxin Prevention: The secondary combustion chamber ensures flue gas stays above 850℃ for more than 2 seconds, fundamentally inhibiting dioxin formation.
Automatic Control: Equipped with Honeywell full-set combustion control components and Allen-Bradley PLC system to realize automatic ignition, purging, temperature regulation and safety interlock.
Main Equipment
Three-chamber RTO main unit, vertical secondary combustion chamber, pneumatic poppet dampers, natural gas combustion system, main fan, purge fan, combustion air fan, instrumentation and monitoring system, steel structure & piping assembly.
Operation Performance
- Treatment efficiency: VOC destruction efficiency ≥ 98%, all exhaust indicators comply with GB16297-1996 and Beijing Local Standard DB11/447-2007.
- Energy saving: Ceramic regenerator achieves a heat recovery efficiency of 95%. The system can operate self-sustainably under high VOC concentration conditions, greatly reducing natural gas consumption.
- Safety: Multi-stage pressure and temperature interlocks are configured. When the EVA fan shuts down, fresh air is automatically supplied to dilute the waste gas to below 20% of the lower explosive limit (LEL), preventing flashback and explosion risks.
- Operation & Maintenance: Mature structure with few wearing parts, suitable for 24/7 continuous operation in chemical parks.
Technical Highlights
- Three-chamber structure and high-tightness poppet dampers ensure stable switching and adapt to fluctuating waste gas working conditions.
- Comply with IEC hazardous area classification standards, with internationally renowned automatic control and flame detection devices for high intrinsic safety.
- 6-minute pre-purging procedure for the furnace effectively prevents accumulation of flammable gas.