Process and installation for thermal hydrolysis of sludge using a group of thermal hydrolysis reactors (71, 72, 73, 74) characterized in that it comprises of the successions of cycles, each of these cycle successions being dedicated to a reactors, each cycle comprising: a step a) of feeding a batch of sludge to be treated no preheated in a reactor (71,72,73,74), said supplying step comprising the passage continuous sludge batch sludge in a dynamic mixer (13) in Which one is injected with the recovery steam； a step b) steam injection live in said reactor (71,72,73,74) containing the batch of sludge so as to increase the temperature and the pressure prevailing in it； a step c) of thermal hydrolysis of the batch of sludge in the thermal hydrolysis reactor； a step d) emptying the contents of the batch of sludge hydrolyzed thermal hydrolysis reactor to a recovery tank (13), and concomitant depressurization of the reactor causing the emission of steam from recovery from the recovery tank (13)； the cycle beginnings of successions of cycles being shifted in time so that steps a) of a succession of cycles concomitant with steps d) of another cycle sequence, the steam of recovery emitted during steps d) of a succession of constituent cycles the steam of recovery injected during steps a) of another succession of cycles.Procédé et installation d'hydrolyse thermique de boues mettant en oeuvre ungroupe deréacteurs d'hydrolyse thermique (71,72,73,74) caractérisé en ce qu'il comprenddessuccessions de cycles, chacune des ces successions de cycle étant dédiée à undes réacteurs,chaque cycle comprenant : une étape a) d'amenée d'un lot de boues à traiternonpréchauffées dans un réacteur (71,72,73,74), ladite étape d'amenée comprenantle passageen continu des boues du lot de boues dans un mélangeur dynamique (13) danslequel estinjectée de la vapeur de récupération ； une étape b) d'injection de vapeurvive dans leditréacteur (71,72,73,74) contenant le lot de bou
