Cement clinker production system and cement clinker production method

Patent metadata

Field	Value
Publication number	US-2023365464-A1
Application number	US-202118246925-A
Country	US
Kind code	A1
Filing date	Sep 29, 2021
Priority date	Dec 17, 2020
Publication date	Nov 16, 2023
Grant date	—

Abstract

A cement clinker producing system, capable of providing a gas containing a carbon dioxide gas at a high concentration by increasing a carbon dioxide gas concentration for a part of an exhaust gas, includes a cyclone preheater to preheat a cement clinker raw material, a rotary kiln to burn the preheated cement clinker raw material so as to provide cement clinker, a calcination furnace to promote decarbonation of the cement clinker raw material, a clinker cooler to cool the cement clinker, a kiln exhaust-gas discharge passages to discharge an exhaust gas generated in the rotary kiln, a combustion-supporting gas supply device to supply a combustion-supporting gas having a higher oxygen concentration than air, a combustion-supporting gas supply passage to guide the combustion-supporting gas to the calcination furnace, and a calcination furnace exhaust-gas discharge passage to discharge a carbon dioxide gas-containing exhaust gas generated in the calcination furnace.

First claim

1 . A cement clinker producing system, comprising:
a cyclone preheater configured to preheat a cement clinker raw material; a rotary kiln configured to burn the cement clinker raw material preheated in the cyclone preheater so as to provide cement clinker; a calcination furnace, which is disposed together with the cyclone preheater on a front stream side of the rotary kiln, and is configured to promote decarbonation of the cement clinker raw material; a clinker cooler, which is disposed on a rear stream side of the rotary kiln, and is configured to cool the cement clinker; and a kiln exhaust-gas discharge passage configured to discharge an exhaust gas generated in the rotary kiln after the exhaust gas passes through the cyclone preheater; wherein the cement clinker producing system further comprising: a combustion-supporting gas supply device configured to supply a combustion-supporting gas having a higher oxygen concentration than an oxygen concentration of air; a combustion-supporting gas supply passage configured to guide the combustion-supporting gas from the combustion-supporting gas supply device to the calcination furnace; and a calcination furnace exhaust-gas discharge passage, which is different from the kiln exhaust-gas discharge passage, configured to discharge a carbon dioxide gas-containing exhaust gas generated in the calcination furnace.

2 . The cement clinker producing system according to claim 1 , further comprising a chlorine bypass device configured to extract and cool a part of the exhaust gas generated in the rotary kiln without allowing the part of the exhaust gas to pass through the cyclone preheater, remove solids, and then discharge an exhaust gas without the solids and classify the solids into coarse powder and fine powder, wherein the classifying is for using the coarse powder as a part of the cement clinker and recovering the fine powder.

3 . The cement clinker producing system according to claim 1 , further comprising a merging flow passage configured to merge a part of the carbon dioxide gas-containing exhaust gas flowing through the calcination furnace exhaust-gas discharge passage into the combustion-supporting gas flowing through the combustion-supporting gas supply passage.

4 . The cement clinker producing system according to claim 1 , further comprising:
a preheated raw-material supply passage configured to supply the preheated cement clinker raw material from the cyclone preheater to the calcination furnace; a first recovery means, which is disposed in the calcination furnace exhaust-gas discharge passage, and is configured to recover a quicklime-containing raw material from the carbon dioxide gas-containing exhaust gas; and a calcination furnace exhaust-gas supply passage, which is coupled to the calcination furnace exhaust-gas discharge passage at a position on a rear stream side of the first recovery means in the calcination furnace exhaust-gas discharge passage, and is configured to merge a part of the carbon dioxide gas-containing exhaust gas flowing through the calcination furnace exhaust-gas discharge passage into the combustion-supporting gas flowing through the combustion-supporting gas supply passage, wherein the cyclone preheater comprises two or more cyclone heat exchangers, wherein the calcination furnace comprises a heating means and is configured to promote the decarbonation of the cement clinker raw material with use of the heating means, and wherein the combustion-supporting gas supply passage is for heat exchange between the carbon dioxide gas-containing exhaust gas flowing through the calcination furnace exhaust-gas discharge passage and the combustion-supporting gas at a position on a front stream side of the first recovery means in the calcination furnace exhaust-gas discharge passage.

5 . The cement clinker producing system according to claim 4 , further comprising a fuel conveying gas supply passage, which branches from at least one of a position in the combustion-supporting gas supply passage, which is closer to the combustion-supporting gas supply device than a portion at which the carbon dioxide gas-containing exhaust gas and the combustion-supporting gas are allowed to exchange heat, or a position in the calcination furnace exhaust-gas supply passage, and is configured to supply a fuel conveying gas to the heating means of the calcination furnace.

6 . The cement clinker producing system according to claim 4 , further comprising an air supply passage configured to convey air in the clinker cooler from the clinker cooler into the kiln exhaust-gas discharge passage.

7 . The cement clinker producing system according to claim 4 ,
wherein the preheated raw-material supply passage is coupled to any one of second to subsequent cyclone heat exchangers from a rearmost stream side in the two or more cyclone heat exchangers of the cyclone preheater, and wherein the cement clinker producing system further comprises: a quicklime-containing raw material supply passage configured to supply the quicklime-containing raw material recovered by the first recovery means from the first recovery means to the cyclone heat exchanger coupled to the preheated raw-material supply passage or a cyclone heat exchanger located on a front stream side of the cyclone heat exchanger in the two or more cyclone heat exchangers; a first decarbonated raw-material supply passage configured to supply the cement clinker raw material decarbonated in the calcination furnace from the calcination furnace to the rotary kiln; a second decarbonated raw-material supply passage configured to supply a part of the decarbonated cement clinker raw material from the first decarbonated raw-material supply passage to a cyclone heat exchanger located on a rearmost stream side in the two or more cyclone heat exchangers; a temperature measurement device configured to measure a temperature of the exhaust gas in the kiln exhaust-gas discharge passage when the exhaust gas passes through the cyclone heat exchanger coupled to the preheated raw-material supply passage; and a decarbonated raw-material supply amount controller configured to adjust an amount of the decarbonated cement clinker raw material to be supplied from the second decarbonated raw-material supply passage to the cyclone heat exchanger located on the rearmost stream side based on the temperature measured by the temperature measurement device and adjust a temperature in the cyclone heat exchanger coupled to the preheated raw-material supply passage through the adjustment of the amount of the decarbonated cement clinker raw material.

8 . The cement clinker producing system according to claim 7 , further comprising a water supply device configured to supply water or a water-containing waste to the exhaust gas flowing through the kiln exhaust-gas discharge passage when the exhaust gas passes through a part of the kiln exhaust-gas discharge passage, the part extending from a portion coupled to the rotary kiln to a portion on a front stream side of the cyclone heat exchanger located on the rearmost stream side.

9 . The cement clinker producing system according to claim 7 , further comprising a denitrating-agent supply device configured to supply a denitrating agent to the exhaust gas flowing through the kiln exhaust-gas discharge passage when the exhaust gas passes through a part of the kiln exhaust-gas discharge passage, the part extending from a portion coupled to the rotary kiln to a portion on the front stream side of the cyclone heat exchanger located on the rearmost stream side.

10 . The cement clinker producing system according to claim 1 , further comprising:
a mixing device configured to mix the carbon dioxide gas-containing exhaust gas

Assignees

• Taiheiyo Cement Corp

Inventors

• Ueno Naoki
• Nomura Koji
• Honma Kenichi
• Terasaki Junichi
• Yoshikawa Tomohisa
• Kimura Takayuki

Classifications

• C25B1/04

  by electrolysis of water · CPC title

• F27D17/25

  using cyclones · CPC title

• F27D17/17

  for preheating fluids, e.g. air or gases · CPC title

• F27B7/2016

  Arrangements of preheating devices for the charge · CPC title

• F27B7/383

  Cooling devices for the charge · CPC title