A shock wave reactor (11a, 11b, 102) for thermal cracking of hydrocarbon-containing feedstock, comprising a casing (4) wherein a duct (10) is formed with inlet (6, 6a) and outlet (7); a rotor (1, 1a) the periphery of which contains an axial- flow blade cascade (2); wherein the casing substantially encloses the periphery of the rotor (la) and a number of stationary vane cascades (8, 9) inside the duct, and further wherein the cascades (2, 8, 9) are configured to direct feedstock containing process stream to repeatedly pass said cascades in accordance with helical trajectory while propagating within the duct between the inlet and outlet and to generate stationary shock-waves to heat the feedstock. The axial- flow rotor cascade (2) is configured to provide kinetic energy and to add velocity to the feedstock containing process stream, and the stationary vanes located downstream the rotor cascade (2) are configured to reduce the velocity of the stream and convert kinetic energy into heat. The reactor may be configured for the realization of thermal cracking processes utilizing hydrocarbons; however it may be utilized for processing carbohydrate- and glyceride-based feedstock, including processing of gaseous biomass matter. Related methods for processing feedstock matter are presented.