This book presents a theoretical and experimental analysis of the solar thermal gasification of petroleum coke, focussing on thermodynamics, chemical kinetics and reactor design. The following main topics are included: (i) Equilibrium computation of the stoichiometric system of pet coke and steam at 1bar and 1300K. (ii) Rate laws for pyrolysis and reactive gasification with steam and carbon dioxide. (iii) Experimental determination of the rate constants using thermogravimetry. (iv) Experiments with a laboratory scale fluidized bed reactor heated by the ETH's high-flux solar simulator using transparent and opaque fluidization tubes. (v) Design and testing of a 5kW solar thermal cavity reactor with entrained flow of gas and solids operated at PSI's solar furnace. (vi) A mathematical reactor model based on the axial dispersion model. The axial dispersion number is obtained from residence time distribution measurements.