Sealing Materials for Pyrolysis Furnace Doors

Sealing Materials for Pyrolysis Furnace Doors

Based on the working conditions of batch pyrolysis furnaces, such as high temperature, micro-negative pressure, and oil vapor presence, common sealing materials are categorized as follows, ranked by applicability:

1. Mainstream High-Temperature Sealing Materials

Ceramic fiber rope/tape/packing

Features: Resistant to high temperatures (up to 1200℃), excellent heat insulation, good elasticity; some varieties are reinforced with stainless steel wire for enhanced wear resistance.

Application: Filling furnace door gaps, tenon-and-groove sealing grooves; it is the basic sealing material for batch pyrolysis furnaces.

Graphite packing/graphite composite gaskets

Features: Resistant to high temperatures (above 1000℃), oil vapor corrosion, and excellent resilience; metal-reinforced graphite gaskets offer stronger pressure-bearing capacity.

Application: Sealing surfaces of flange bolt-type furnace doors and self-tightening sealing structures of quick-opening furnace doors; it is the mainstream choice in the industry.

Glass fiber packing

Features: Resistant to high temperatures (1000℃), non-toxic, environmentally friendly, and low-cost; can be reinforced with metal wire for increased strength.

Application: Auxiliary sealing for furnace doors in medium-to-low temperature (≤800℃) conditions, or as a low-cost alternative to ceramic fiber.

2. Enhanced Materials for Special Working Conditions

Metal wound gaskets

Features: Made by winding graphite and stainless steel strips, offering high temperature resistance, high pressure resistance, and corrosion resistance; extremely reliable sealing performance.

Application: Main sealing surfaces of flange bolt-type furnace doors, or high-pressure conditions requiring high sealing precision.

Water-cooled sealing gaskets (composite structure)

Features: Supported by a metal frame, embedded with ceramic fiber or graphite, and equipped with a cooling water jacket for heat dissipation; can withstand extreme temperatures above 1400℃.

Application: Large-scale pyrolysis furnaces processing high-ash, high-abrasion raw materials to prevent furnace door deformation and seal failure.

High-temperature silicone rubber/fluororubber gaskets

Features: Good elasticity and oil resistance, but limited high-temperature tolerance (silicone rubber ≤300℃, fluororubber ≤250℃).

Application: Auxiliary sealing for low-temperature parts such as furnace door observation windows, or as a buffer layer for high-temperature seals.

3. Auxiliary Sealing Materials

High-temperature sealant: Inorganic silicate adhesive or silicone-modified adhesive, resistant to temperatures above 1000℃, used for filling gaps in sealing surfaces to enhance overall sealing performance.

Metal foil-reinforced ceramic fiber tape: Laminated with stainless steel foil on the surface, combining high temperature resistance and wear resistance, suitable for frequently opened quick-opening furnace doors.

Selection Principles

Temperature matching: Prioritize materials with long-term temperature resistance ≥800℃ to avoid material embrittlement due to short-term high temperatures.

Medium compatibility: For oil vapor-containing conditions, choose oil-resistant materials such as graphite or fluororubber to prevent seal swelling and failure.

Operational adaptability: Quick-opening furnace doors require highly resilient materials (e.g., graphite packing), while flange bolt-type furnace doors can use metal wound gaskets to improve pressure-bearing capacity.