Method for capturing co2 produced by cement plants by using the calcium cycle

A method for capturing CO2 produced by cement plants by using the calcium cycle method wherein the cement is produced by the cement plant by the following method:

• grinding of raw materials comprising limestone, clay, and iron ore;
• homogenizing the raw materials in order to produce a raw meal;
• preheat the raw meal in the preheater section of a cement kiln in order to produce a preheated raw meal;
• calcining the preheated raw meal in the calcining section of the cement kiln in order to produce a calcined raw meal;
• feed said calcined raw meal into a rotary kiln in order to produce a clinker;
• cooling the clinker and feeding it to a mill in order to mix the clinker with gypsum and produce cement, wherein the cement kiln calciner section and rotary kiln produce combustion gases which are cooled and have a content of between a 15 to 30% of CO2 and unreacted raw meal containing CaCO3 which is filtered from the gas;
• and wherein the calcium cycle method comprise:
• contacting said combustion gases containing CO2 with a solid stream having a high CaO content inside a first fluidized bed reactor in order to produce an exothermic reaction between the CO2 and the CaO for producing a solid-gas mixture comprised by a CaCO3 stream and a gaseous stream having a lower CO2;
• content feeding said solid-gas stream to a cyclone for separating the solids from the gaseous stream and obtaining CaCO3 solids and a hot gaseous having a lower CO2 content;
• feeding the CaCO3 solids into a second fluidized bed reactor to which it is provided heat by means of a combustion reaction, in order to decarbonate the CaCO3 and produce a solid-gas mix comprised by a solid CaO stream and a gas stream comprised mainly by hot CO2 coming from the gaseous stream leaving the cement plant and from the combustion reaction that provides heat to second fluidized bed;
• feeding the solid CaO stream and hot CO2 stream into a second cyclone in order to separate the solids from the hot CO2 and produce a hot CO2 stream separated from a solid CaO stream;
• and recycling the CaO to the first fluidized bed reactor, wherein the method of the present invention comprise:
• feeding the combustion gases produced by the calciner section and by the rotary kiln of the cement production plant to the first fluidized bed reactor of the calcium cycle method;
• feeding the solid CaO stream separated by the second cyclone to the first fluidized bed reactor;
• purging an amount of the CaO separated by the second cyclone when the capacity of the CaO to react with the CO2 drops, and feeding it directly to the cement plant rotary kiln;
• and
• making up fresh CaO to the second fluidized bed reactor of the calcium cycle method.