Temperature difference control (TDC) schemes can clearly suppress the adverse influence of pressure variations on product quality control of various distillation columns (DCs) by employing temperature differences (TDs) between the sensitive stage temperature (

T

S

) and reference stage temperature (

T

R

)

i.e

.

T

S

-

T

R

to infer the controlled product qualities. However

because the TDC scheme has failed to specially take the corresponding relationship between the TD employed in each control loop and the controlled product quality into account

it may suffer from relatively large steady-state errors in the controlled product qualities. To address this problem

an enhanced TDC (ETDC) scheme is proposed in the current article

in which an enhanced TD (ETD)

i.e

.

T

S

-

α

×

T

R

is employed to replace the conventional TD for each control loop. While the locations of the sensitive and reference stages of the ETD are respectively determined according to sensitivity analysis and SVD analysis

the adjusted coefficient α is set to be the ratio b

etween the averaged absolute variation magnitudes (AAVMs) of the

T

S

and

T

R

so that the relationship between the

T

S

and

T

R

can be appropriately coordinated. With reference to the operations of three different distillation systems

i.e

.

one conventional DC distilling an ethanol (E)/butanol (B) binary mixture

one conventional DC distilling an E/propanol (P)/B ternary mixture

and one dividing-wall distillation column distilling an E/P/B ternary mixture

the performance of the ETDC scheme is assessed by compared with the conventional TDC scheme and the double TD control (DTDC) scheme. The dynamic simulation results show that the ETDC scheme is better than the conventional TDC scheme with reduced steady-state errors in the controlled product qualities and improved dynamic responses

and is comparable with the DTDC scheme despite the less temperature measurements are employed.