Reactivation of sorbent in a fluid bed boiler

In a circulating fluidized bed combustion process for burning a sulfur-containing fuel in a circulating bed of fluidized sorbent particles in a combustor to generate flue gas and sulfur dioxides, separating the generated flue gas from the circulating particles and returning the separated particles to the combustor wherein the sulfur oxides react with sorbent material on the surface of said sorbent particles and wherein unreacted sorbent material remains inside said particles, the improvement comprising injecting a jet of fracturing medium of liquid water or steam at a sufficiently high pressure and direcrted so as to impinge upon said sorbent particles containing unreated sorbent material inside whereby said sorbent particles are mechanically fractured to expose said unreacted sorbent material to said sulfur oxides.