Note:

This calculator estimates the turnaround time during homogeneous-vessel venting when there is a constant external heat input. It determines the time available to take action before a critical event, considering the effects of vaporization and external heating. This is vital for assessing safety in scenarios with external heat sources.

Formula Explanation:

The formula calculates the turnaround time (τ) by subtracting the time required to vaporize the liquid due to external heat input from the emptying time (tr). It provides an estimate of the time window for intervention.

Parameters:

• τ (Turnaround Time): The time available before a critical event occurs.
• tr (Emptying Time): The time it takes to empty the vessel without external heating.
• V (Volume): The volume of the vessel.
• hfa (Latent Heat): The latent heat of vaporization, representing the energy required to vaporize the liquid.
• QT (Constant External Heat Input): The constant rate of heat input from an external source.
• vfa (Specific Volume): The specific volume of the liquid.

Real-life Applications:

• Chemical Process Safety: Estimating the time available to respond to a thermal event with external heating (e.g., fire exposure).
• Emergency Relief System Design: Assessing the required activation time for emergency systems.
• Thermal Hazard Analysis: Evaluating the potential for thermal runaway in processes with external heat sources.

Conclusion:

This calculation helps in understanding the time constraints during venting processes with external heating. Accurate input is crucial for reliable results and effective safety planning. The turnaround time provides a critical metric for emergency response and risk mitigation.