A method of facilitating simulations of industrial processes is disclosed. The method can be applied to the simulation of hydrocarbon processing, including oil and gas processing and production, refining and petrochemicals processing. The method includes receiving process information defining a process for simulation; creating and storing at least one rule defining a time-dependent property of the process information; and simulating the process based on the received process information under variation of the time-dependent property of the process information. An associated apparatus is also disclosed.