Enhanced electricity cogeneration in cement clinker production

A method to produce electricity in a cement clinker production unit, comprising:

• providing the cement clinker production unit with rotary kiln and a precalciner as combustion chambers to generate electricity, the precalciner comprising successively a precalciner combustor receiving raw meal and generating at least partially precalcined meal and a precalciner separator receiving the at least partially precalcined meal from the precalciner combustor;
• supplying a first quantity of fuel to the precalciner and a second quantity of fuel to the rotary kiln, the sum of the first quantity and the second quantity corresponding to at least 110% of an optimized heat value requirement for the clinker production operation of the precalciner and the rotary kiln per unit weight of clinker;
• leading hot flue gasses from the rotary kiln, through the precalciner combustor, through the precalciner separator, and to a heat recovery steam generator along a first flow path, wherein the heat recovery steam generator produces steam;
• bypassing a portion of hot flue gases from the rotary kiln that includes bypassing a first portion of hot flue gases from the rotary kiln and bypassing a second portion of hot flue gases from the precalciner separator and wherein a ratio of mass flow rate of the first portion of hot flue gases and the second portion of hot flue gases is less than 0.5;
• leading the first portion of hot flue gases from the rotary kiln to the heat recovery steam generator along a second flow path, wherein the second flow path does not pass through the precalciner separator or the precalciner combustor;
• leading the second portion of hot flue gases from the rotary kiln, through the precalciner separator, and to the heat recovery steam generator along a third flow path;
• and
• producing electricity with a power island comprising a steam turbine equipped with an electrical generator operable in response to the produced steam.