An extensively long computation time makes it difficult to apply mixed-integer linear programming (MILP)-based simultaneous compensation to large industrial processes. This paper shows successful application of the MILP-based simultaneous compensation to a large industrial process of a byproduct gases network. To reduce the computation time, the set of gross error candidates is calculated before MILP formulation, and then a simultaneous compensation problem is formulated to identify the existence of gross errors from the members of the gross error candidate set. A significant reduction in the computation time makes it possible to apply the MILP-based simultaneous method to hourly management of byproduct gases. Gross errors are identified in measuring instruments for byproduct gas generation and are corrected by the MILP with the gross error candidate method. Variances of the rectified flow rates are smaller than those of measurements, which shows that random and gross errors are corrected by the MILP with the gross error candidate method.