Patent ID: 6749681
Filing Date: 2004-06-15
Classification: C04B,F22B,Y02P

Abstract:
In a method of producing cement clinker and electricity, comprising feeding cement raw mix and hydrocarbon in a circulating fluidized bed, calcining the cement raw mix in the circulating fluidized bed and producing steam therein, discharging hot bed material in a rotary kiln, clinkering the calcined material in the rotary kiln and subsequently cooling the clinker, further comprising the gas and the solids out of the fluidized bed entering a cyclone, the solids being separated therein being returned to the bed, whereby part of those solids being first cooled down in a solids heat exchanger producing steam, whereas the gas and the fly ash escaping the cyclone being passed through at least one heat exchanger and through a filter, further comprising the produced steam being fed to a steam turbine island comprising a steam turbine being drivingly connected to a generator, the improvement comprisingfeeding part of the cement raw mix in pulverized form, lime-rich fly ash obtained from calcination of limestone from the pulverized part of the cement raw mix escaping the cyclone system, feeding the predominant part of the remaining part of the cement raw mix in crushed form for forming bed and circulating material, and grinding the hot bed material as well as additives before blending them with lime being separated in the filter, separated in the filter, obtained from calcination of limestone in the cement raw mix.