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1. Typical range of evaporation rate – Low evaporation rate design: Advanced storage tanks using high-vacuum multi-layer insulation (such as multiple layers of aluminum foil + glass fiber) or vacuum powder insulation (such as perlite) can achieve an evaporation rate as low as 0.02%~0.05%/day. - Standard design: The evaporation rate of ordinary vacuum-insulated jacketed storage tanks is usually between 0.05% and 0.1%/day. Example calculation: If the tank volume is 1,000 cubic meters and the evaporation rate is 0.1%/day, then the daily evaporation amount is approximately 1 cubic meter of ethylene. 2. Key factors affecting evaporation rate – Insulating materials and vacuum level: – Vacuum multi-layer insulation (VIP) is more effective than vacuum powder insulation (such as perlite), but it is more expensive. - The vacuum level needs to be maintained over the long term (usually below 1×10⁻² Pa); if the vacuum jacket leaks, the evaporation rate will increase significantly. - Tank design: – Jacket thickness, thermal bridge design of the support structure (to minimize heat conduction paths). - Tank size (large storage tanks generally have a better evaporation rate due to their lower surface area-to-volume ratio). - Environmental conditions: – High temperatures or high humidity increase the transfer of external heat, leading to an increased evaporation rate. - The shading and ventilation measures of the storage tank also affect its performance. - Operating pressure: The boiling point of ethylene at atmospheric pressure is -103.7°C; if the storage tank is designed for low pressure (near atmospheric pressure), the evaporation rate is even lower ； The evaporation rate of pressurized storage tanks (such as 0.2~0.3 MPa) may be slightly higher, but emissions can be reduced through pressure control. 3. Optimization measures in practical applications – Regular maintenance of the vacuum system: Ensure stable vacuum levels in the jacket to prevent a decline in insulation performance. - Thermal shielding technology: Adding a radiation shielding layer (such as aluminum foil) inside the jacket to reduce radiation heat transfer. - Vapor recovery: Recover the evaporated ethylene through a recondensation system or compressor to reduce actual losses. 4. Comparison with other media - LNG tanks: BOR is typically 0.05%~0.15%/day (the evaporation rate of ethylene is slightly lower due to its higher boiling point than that of LNG at -162°C). - Liquid nitrogen storage tank: BOR is approximately 0.1%~0.3%/day (ethylene storage tanks require higher insulation but lower temperatures, so the evaporation rate is lower). In summary, vacuum-insulated jacketed ethylene storage tanks can maintain an evaporation rate of 0.02%–0.1%/day thanks to their efficient insulation design; the exact value depends on the actual operating conditions and design parameters. Under ideal conditions, advanced storage tanks can even achieve lower evaporation rates, but care must be taken regarding maintenance costs and operational complexity. For accurate data, it is recommended to refer to the manufacturer’s technical specifications or the results of thermodynamic simulations for the specific project.