Method of producing clinker from cement raw meal

Patent metadata

Field	Value
Publication number	US-2024002288-A1
Application number	US-202118255311-A
Country	US
Kind code	A1
Filing date	Dec 7, 2021
Priority date	Dec 9, 2020
Publication date	Jan 4, 2024
Grant date	—

Abstract

A method of producing clinker from cement raw meal, includes preheating cement raw meal in a preheater string, the preheater string including a plurality of preheater stages, pre-calcining preheated raw meal in a pre-calciner to obtain a pre-calcined product, introducing the pre-calcined product into a rotary kiln for calcining the pre-calcined product to obtain cement clinker, wherein a partial flow of at least partly preheated raw meal is diverted from the preheater string, introduced into a calcination device and at least partially decarbonated in the calcination device in order to obtain an at least partially decarbonated product and CO2, wherein the calcination device is heated by electrical energy, and wherein the at least partially decarbonated product is fed into the rotary kiln and the CO2 is drawn off from the calcination device.

First claim

1 . A method of producing clinker from cement raw meal, comprising:
preheating cement raw meal in a preheater string, said preheater string comprising a plurality of preheater stages, pre-calcining preheated raw meal in a pre-calciner to obtain a pre-calcined product, introducing the pre-calcined product into a rotary kiln for calcining the pre-calcined product to obtain cement clinker,
wherein a partial flow of at least partly preheated raw meal is diverted from the preheater string, introduced into a calcination device and at least partially decarbonated in the calcination device in order to obtain an at least partially decarbonated product and CO 2 , wherein the calcination device is heated by electrical energy, and wherein the at least partially decarbonated product is fed into the rotary kiln and the CO 2 is drawn off from the calcination device.

2 . The method according to claim 1 , wherein the at least partly preheated raw meal is extracted from the preheater string at a temperature of 650-750° C.

3 . The method according to claim 1 , wherein the at least partly preheated raw meal is heated to a temperature of 750-950° C. in the calcination device.

4 . The method according to claim 1 , wherein decarbonating the at least partly preheated raw meal comprises converting limestone into CaO and CO 2 .

5 . The method according to claim 1 , wherein the least partly preheated raw meal is transported through the calcination device by means of a screw conveyor while being at least partially decarbonated.

6 . The method according to claim 1 , wherein the calcination device is configured as a screw conveyor.

7 . The method according to claim 6 , wherein a conveyor screw of the screw conveyor is configured as a heating element that is heated by electrical energy, such as by resistance heating.

8 . The method according to claim 1 , wherein the CO 2 drawn off from the calcination device is fed through a heat exchanger, in which a fluid or gaseous medium is heated by heat exchange with the CO 2 .

9 . The method according to claim 8 , wherein heat obtained by heat exchange with the CO 2 is used in a thermodynamic cycle to evaporate a working fluid of said thermodynamic cycle.

10 . The method according to claim 9 , wherein the thermodynamic cycle is designed as a gas turbine process or as an Organic Rankine Cycle.

11 . The method according to claim 10 , wherein a gas turbine of the gas turbine process or of the Organic Rankine Cycle is used to generate electrical energy by means of an electrical generator and wherein the electrical energy is optionally fed to the calcination device for electrically heating the same.

12 . The method according to claim 1 any one of claim 1 , wherein the CO 2 drawn off from the calcination device is fed to a reactor, in which CO 2 and further reactants are transformed into a synthetic fuel.

13 . A device for carrying out a method according to claim 1 , comprising:
a preheater string for preheating cement raw meal, said preheater string comprising a plurality of preheater stages, a pre-calciner for pre-calcining preheated raw meal to obtain a pre-calcined product, a rotary kiln for calcining the pre-calcined product to obtain cement clinker, a calcination device having electrical heating means, said calcination device comprising an inlet that is connected to the preheater string to divert a partial flow of at least partly preheated raw meal from the preheater string and introduce the same into the calcination device in order to obtain an at least partially decarbonated product and CO 2 , said calcination device comprising an outlet that is connected to the rotary kiln for feeding the at least partially decarbonated product into the rotary kiln, and said calcination device comprising a CO 2 discharge opening for drawing off the CO 2 from the calcination device.

14 . The device according to claim 13 , wherein the calcination device comprises at least one contact heating element that is arranged to be in heat exchanging contact with the at least partly preheated raw meal while the same is being conveyed from the inlet to the outlet, wherein said at least one contact heating element is configured to be heated by the electrical heating means.

15 . The device according to claim 13 , wherein the calcination device comprises a screw conveyor for conveying the at least partly preheated raw meal from the inlet to the outlet.

16 . The device according to claim 15 , wherein a conveyor screw of the screw conveyor is configured as the at least one contact heating element.

17 . The device according to claim 13 , wherein the electrical heating means is configured as a resistance heating.

18 . The device according to claim 13 , wherein the CO 2 discharge opening is connected to a heat exchanger, in which a fluid or gaseous medium is heated by heat exchange with the CO 2 .

19 . The device according to claim 13 , wherein a thermodynamic cycle is provided, which comprises an evaporator and which is arranged so that heat obtained by heat exchange with the CO 2 is used in the thermodynamic cycle to evaporate a working fluid of said thermodynamic cycle in said evaporator.

20 . The device according to claim 19 , wherein the thermodynamic cycle is designed as a gas turbine process or as an Organic Rankine Cycle.

21 . The device according to claim 20 , wherein a gas turbine of the gas turbine process or of the Organic Rankine Cycle is connected to an electrical generator and wherein the electrical energy generated by said electrical generator is optionally fed to the calcination device for electrically heating the same.

22 . The method according to claim 2 , wherein the at least partly preheated raw meal is extracted from the preheater string at a temperature of 680-720° C.

23 . The method according to claim 3 , wherein the at least partly preheated raw meal is heated to a temperature of 800-950° C.

24 . The method according to claim 23 , wherein the at least partly preheated raw meal is heated to a temperature of 850-900° C.

Assignees

• Holcim Technology Ltd

Inventors

• Bucher Ernst
• Brusco Guillermo
• Blum Rudy
• Stoffel Beat
• Weihrauch Michael

Classifications

• F27D17/30

  Arrangements for extraction or collection of waste gases; Hoods therefor · CPC title

• F27D17/10

  Arrangements for using waste heat · CPC title

• C04B7/46 Primary

  electric · CPC title

• C04B7/432 Primary

  Preheating without addition of fuel · CPC title

• C04B7/475

  using the waste heat, e.g. of the cooled clinker, in an other way than by simple heat exchange in the cement production line, e.g. for generating steam · CPC title