For a 52L hydrogen storage tank, the pressure is 70 Mpa at 15°C. What is the pressure inside the tank when the temperature rises to 110°C? How to calculate it?
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For a 52L hydrogen storage tank, the pressure is 70 Mpa at 15°C. What is the pressure inside the tank when the temperature rises to 110°C? How to calculate it?
P15/T15=P110/T110 P15, T15——pressure and temperature at 15°C； P110, T110 — Pressure and temperature at 110°C. Is this formula okay?
pV=nRT (Clapeyron equation); p is the gas pressure, in Pa. V is the gas volume, in m3. n is the amount of substance of the gas, in units of mol, T is the temperature of the system, and for an ideal gas the state equation uses K as the unit. R is the proportionality constant, which varies depending on the conditions; its unit is J/(mol·K). In equation of state expressed in terms of moles, R is a constant value that remains the same for any ideal gas, approximately 8.31441±0.00026 J/(mol·K). Then one should know the proportional relationship between pressure and temperature.
For a simple calculation, using the ideal gas law is sufficient. For details, one needs to consult a table or use property software.
Although the pressure is already high, for hydrogen it is still possible to estimate the effect of temperature on pressure using the ideal gas law. At a constant volume and constant amount of moles, temperature is directly proportional to pressure; that is, as the temperature rises, the pressure rises as well. P110=P15*(273.15+110)/(273.15+15)=70*1.33=93.08MPa.