def A_approx_deph(Qload_deph, deltaT_diff_deph, Kt_approx):
    """
    Calculates the approximate heatransfer area.
    Parameters
    ----------
    Qload_deph : float
        The heat load of dephlegmator, [W] , [J/s]
    deltaT_diff_deph : float
        The coefficient difference of temperatures, [C]
    Kt_approx : float
        The heatransfer coefficient [W/(m**2 * degrees celcium)]
    Returns
    -------
    A_approx_deph : float
        The approximate heatransfer area of dephlegmator, [m**2]
    References
    ----------
    Романков, формула 4.72, стр.168
    """           
    return Qload_deph / (deltaT_diff_deph * Kt_approx)