A method for creating a linear programming (LP) model of an industrial process facility is disclosed. The model may be used for interactively simulating and/or optimizing the operation of the facility to facilitate feedstock selection and/or other economic analyses. According to the inventive method, a first principles reference tool is used to create a non-linear reference model of the entire facility. Then, independent input variables and key output variables are specified, and initial values for the independent input variables are specified. Base case values for each key output variable are determined by running the non-linear reference model using the specified initial values for the independent input variables. Next, partial derivatives for each key output variable with respect to each independent input variable are determined. A matrix is constructed containing the base case values and partial derivatives. The matrix serves as the depiction of the industrial process facility in the final LP, which may also include prices, availabilities, and other external constraints.