Oil sludge, if unused, is one of the major industrial wastes requiring trea
tment from petroleum refinery plants or the petrochemical industry. It cont
ains a large amount of combustibles with high heating values. The treatment
of waste oil sludge by burning has certain benefits; however, it cannot pr
ovide the useful resource efficiently. On the other hand, the conversion of
oil sludge to lower molecular weight organic compounds by pyrolysis not on
ly solves the disposal problem but also has the appeal of resource utilizat
ion. The major sources of oil sludge include the oil storage tank sludge, t
he biological sludge, the dissolve air flotation (DAF) scum, the American P
etroleum Institute (API) separator sludge and the chemical sludge. In this
study, the oil sludge from the oil storage tank of a typical petroleum refi
nery plant located in northern Taiwan is used as the raw material of pyroly
sis. Its heating value of dry basis and low heating value of wet basis are
about 10681 kcal kg(-1) and 5870 kcal kg(-1), respectively. The removal of
the moisture from oil sludge significantly increases its heating value. The
pyrolysis of oil sludge is conducted by the use of nitrogen as the carrier
gas in the temperature range of 380-1073 K and at various constant heating
rates of 5.2, 12.8 and 21.8 K min(-1). The pyrolytic reaction is significa
nt at 450-800 K and complex. For the sake of simplicity and engineering use
, a one-reaction kinetic model is proposed for the pyrolysis of oil sludge,
and is found to satisfactorily fit the experimental data. The activation e
nergy, reaction order and frequency factor of the corresponding pyrolysis r
eaction in nitrogen for oil sludge are 78.22 kJ mol(-1), 2.92 and 9.48 x 10
(5) min(-1), respectively. For precise use, the two- and three-reaction mod
els are proposed to describe the pyrolysis results. Among the three models
proposed, the three-reaction model gives the best fit. These results are ve
ry useful for the proper design of the pyrolysis system of the oil sludge u
nder investigation. (C) 2000 Society of Chemical Industry.