Modelling of a distillation column with operating state changes

A method for operating a distillation column (12) having multiple column stages for separating a feed fluid stream into individual fluid components, comprising:

• determining a state of the distillation column from a plurality of states by means of a model in a manner dependent on pressure differences prevailing between each two adjacent column stages of said multiple column stages, wherein the plurality of states represent a complete operating range of the distillation column,
• wherein, in the model, both gaseous flows and liquid flows between the each two adjacent column stages are determinded by the pressure differences prevailing between the each two adjacent column stages,
• wherein, in the model, a substance quantity flow {dot over (N)}V which characterizes the gaseous flow between the each two adjacent column stages of said multiple column stages is given by {dot over (N)}V·RV=CV·ΔpV, and a substance quantity flow {dot over (N)}L which characterizes the liquid flow between the each two adjacent column stages is given by {dot over (N)}L·RL=CL·ΔpL,
• wherein, Δpv is a total gaseous pressure difference between the each two adjacent column stages, ΔpL is a total liquid pressure difference between the each two adjacent column stages, RV is a gaseous coefficient of resistance between the each two adjacent column stages, RL is a liquid coefficient of resistance between the two each adjacent column stages,
• CV is a gaseous conductance value of the gaseous flow between the two each adjacent column stages, and CL is a liquid conductance value of the liquid flow between the two each adjacent column stages,
• on the basis of the determined state, for at least one manipulated variable influencing the state, setting a manipulated variable value influencing the state, in a manner dependent on at least one control variable, wherein the at least one control variable comprises a product quality, a product volume flow, a product mass flow or a cost variable, and
• operating the distillation column (12) using the determined state of the distillation column (12) using the at least one control variable.