ZEMSIL® в нефтегазовой отрасли

Silicone Materials in Oil and Gas

The oil and gas industry spans upstream (drilling, production), midstream (pipeline, compression), and downstream (refining, petrochemicals) operations — each with distinct temperature, chemical exposure, and mechanical requirements. Silicone materials appear across all three segments, though they are not the universal seal material: compatibility with specific hydrocarbons, H₂S, and aromatic streams must be assessed. Where silicone is specified, it typically wins on temperature range, low-temperature flexibility, or defoaming performance that organic alternatives cannot match.

Seals and Gaskets: Where Silicone Is Specified

PDMS silicone rubber swells significantly in aliphatic and aromatic hydrocarbons — this is a known limitation. Standard silicone O-rings and gaskets are not suitable for hydrocarbon stream sealing in oil production or refining. The exceptions and replacements:

Fluorosilicone (FVMQ) — FL series: The trifluoropropyl side groups dramatically reduce swell in fuels, oils, and aromatic solvents. ZEMSIL FL fluorosilicone maintains volume swell <10% in ASTM Fuel C, <15% in ASTM Oil No. 3, and operates from -55 °C to +175 °C. Applications:

• Wellhead flange seals in gas condensate and crude oil service
• Fuel system seals in gas turbine generators (common on offshore platforms)
• Hydraulic fluid seals on drilling control systems (water-glycol and mineral-oil hydraulics)
• Meter body seals and flow computer interface seals

Standard PDMS sealants (SS-N, SS-S, SB-RTV2) in non-hydrocarbon zones: instrument enclosure seals, electrical junction box seals, HVAC penetrations in offshore modules, and exterior cladding joints on process buildings use standard silicone sealants where hydrocarbon exposure is indirect or absent. These benefit from silicone's UV, ozone, and salt-fog resistance in offshore environments.

High-Temperature Applications in Refining

Fluid catalytic cracking (FCC), hydrocracking, and catalytic reforming units operate at 400–550 °C — well beyond any polymer seal. However, silicone materials appear at lower-temperature support functions:

• Instrumentation and analyzer sample conditioning lines: where process fluid temperature is reduced to sensor operating range (<200 °C), silicone-insulated cable and silicone tubing connectors are used
• Expansion joint backup seals: between ceramic and metallic expansion joint components at 150–300 °C interface temperatures
• Heat tracing tape insulation: HTV silicone rubber jackets on steam and electric heat tracing for freeze protection at ambient conditions up to 200 °C

SS-S silicone sealant (solvent-based, high-temperature grade) and SB-HTV silicone rubber compound fill these mid-temperature insulation roles.

Silicone Defoamers in Oil and Gas Processing

Foam is a persistent process problem across oil and gas: in crude oil separators, amine gas-treating units (MEA/MDEA/DEA), glycol dehydration columns, produced-water treatment, and gas compression lube oil systems. Silicone polydimethylsiloxane (PDMS) defoamers are effective at ppm-level dosing because they spread rapidly at the foam film interface, destabilizing the film by reducing surface viscosity.

ZEMSIL defoamer products for oil and gas:

Dosing is typically 1–50 ppm active silicone. At high dose, silicone defoamers can contaminate downstream catalysts — catalyst vendors specify maximum silicone carry-over (often <50 ppb Si at reactor inlet). This is managed by dosing at the minimum effective level and using emulsion forms with better dispersion/dilution profiles.

Anti-Corrosion and Protective Coatings

Offshore and onshore process equipment faces corrosion from salt spray, H₂S, CO₂, and organic acids. Silicone-modified resins provide heat and corrosion resistance:

Silicone-alkyd and silicone-polyester topcoats: used on exhaust stacks, heat exchangers, and fired heater casing where temperatures reach 200–400 °C and conventional organic coatings carbonize. Silicone content 30–60% (silicone-modified alkyd) to >80% (pure silicone). ZEMSIL SR-AC (silicone-acrylic resin) and SR-M (methyl silicone resin) are binder components for high-temperature coatings.

Zinc-rich primer with silicone topcoat: two-coat system for structural steel on offshore topsides and LNG facilities — zinc-rich epoxy primer provides galvanic protection, silicone topcoat provides heat and UV resistance. Common specification for equipment operating to 250 °C.

Silane surface treatment before coating: CS-560 (epoxysilane) and CS-550 (aminosilane) used as adhesion promoters in coating formulations applied to steel, aluminum, or galvanized substrates to improve coating adhesion in wet/corrosive environments.

Silane Coupling Agents in Elastomeric Seals

Fluorosilicone and HTV silicone rubber compounds for oil and gas seals incorporate fumed silica (FS-200, FS-300) as reinforcing filler. To achieve full reinforcement, the silica surface must be treated with silane coupling agents:

• CS-580 (methacrylsilane) and CS-570 (methacryloxysilane): for peroxide-cured compounds
• CS-550 (aminosilane) or CS-560 (epoxysilane): for condensation-cured RTV compounds

Silane treatment improves tensile strength by 30–60% vs untreated silica, and eliminates moisture-driven strength degradation in humid or immersed service — critical for subsea or wellhead seal compounds.

Related Reading

Fluorosilicone FL series, Defoamer DF-B, Silicone resin SR-AC, Fumed silica FS-200, CS-560 silane coupling agent, Sealing applications, Chemical processing industry guide.