Effect of iron and sulphur dosage in coal liquefaction : modelling and optimisation

Abstract Hydrogenation reactions using Samla, Kottadih coal and low temperature tar oil (230–330°C) at different iron and sulphur concentrations have been carried out in a batch autoclave under a constant H 2 pressure of 24.5 ± 0.2 MPa at 450°C. Non-linear parameter estimation and statistical analysis reveal that variation of total, coal, benzene soluble product (BSP) and asphaltene conversions with iron and sulfur dosage can be explained quite satisfactorily through a simple second order regression model. Furthermore, optimisation of multivariable, non-linear objective functions under various sets of non-linear constraints indicate that at specific dosages of iron and sulphur the oil yield becomes maximum with the minimum yield of undesired products.