def Q_deph(P_mass, r_dist, R):
    """
    Calculates the heat load of dephlegmator.
    Parameters
    ----------
    P_mass : float
        The mass flow rate of dist , [kg/s]
    R : float
        The reflux number [dimensionless]
    r_dist : float
        The heat vaporazation of dist, [J/kg]
    Returns
    -------
    Q_deph : float
        The heat load of dephlegmator, [W] , [J/s]
    References
    ----------
    Дытнерский, формула 2.2, стр.45
    """   
    return P_mass * (R + 1) * r_dist