You can calculate kilowatts from kilojoules and seconds, but you can't convert kilojoules to kilowatts, since kilojoule and kilowatt units represent different quantities.
The power P in kilowatts (kW) is equal to the energy E in kilojoules (kJ), divided by the time period t in seconds (s):
P(kW) = E(kJ) / t(s)
kilowatt = kilojoule / second
kW = kJ / s
What is the power consumption of an electrical circuit that has energy consumption of 9 kilojoules for time duration of 3 seconds?
P(kW) = 9kJ / 3s = 3kW