Oxy-calcination process

Patent metadata

Field	Value
Publication number	US-10633282-B2
Application number	US-201515532325-A
Country	US
Kind code	B2
Filing date	Nov 30, 2015
Priority date	Dec 1, 2014
Publication date	Apr 28, 2020
Grant date	Apr 28, 2020

Abstract

Method and installation for calcining cement raw meal in a calciner whereby fuel and a calciner oxidant having an oxygen content of at least 30% vol are introduced into the calciner so as to generate either an oxidant-lean zone or a fuel-lean zone in the calciner located between the lowermost fuel inlet level and the lowermost oxidant inlet level of the calciner, between 50% and 100% by weight of the raw meal being supplied to the calciner upstream of and/or within the oxidant-lean, respectively the fuel-lean zone.

First claim

What is claimed is:

1. A method of calcining cement raw meal in a calciner having a total calciner height and extending between a bottom end and a top end in a longitudinal direction, said method comprising:
introducing fuel and calciner oxidant into the calciner so that to ensure complete or substantially complete combustion of the fuel with the calciner oxidant and generate heat inside the calciner, the calciner oxidant having an oxygen content of at least 30% vol and being introduced into the calciner at at least one oxidant inlet level, said at least one oxidant inlet level consisting of or including a lowermost oxidant inlet level; the fuel being introduced into the calciner at at least one fuel inlet level, said at least one fuel inlet level consisting of or comprising a lowermost fuel inlet level;
supplying the raw meal is to the calciner, entrained towards the top end by an upward gas flow within the calciner and calcined to generate calcined meal, the calcined meal being evacuated from the calciner at the top end together with a calciner flue gas, the upward gas flow comprising flue gases generated by the combustion of the fuel with the calciner oxidant, decarbonation gas generated by a decarbonation of the raw meal and part of the calciner flue gas which is introduced into the calciner at the bottom end as a recycle flue gas; and
separating the calcined meal from the calciner flue gas and part of the separated calciner flue gas is introduced into the calciner as the recycle flue gas, wherein:
the lowermost oxidant inlet level is located downstream of the lowermost fuel inlet level at an oxygen-lean zone distance Do>0 from said lowermost fuel inlet level thereby creating an oxygen-lean zone in the calciner in which fuel is mixed with the recycle flue gas, said oxygen-lean zone being located between the lowermost fuel inlet level and the lowermost oxidant inlet level, between 50% and 100% by weight of the raw meal being supplied to the calciner upstream of and/or at the lowermost oxidant inlet level, or
the lowermost fuel inlet level is located at a fuel-lean zone distance Df>0 downstream of the lowermost oxidant inlet thereby creating a fuel-lean zone in the calciner between the lowermost oxidant inlet level and the lowermost fuel inlet level in which calciner oxidant is mixed with the recycled flue gas, between 50% and 100% by weight of the raw meal being supplied to the calciner upstream of and/or at the lowermost fuel inlet level.

2. The method of claim 1 , wherein:
the lowermost oxidant inlet level is located downstream of the lowermost fuel inlet level at an oxygen-lean zone distance Do>0 from said lowermost fuel inlet level thereby creating an oxygen-lean zone in the calciner in which fuel is mixed with the recycle flue gas, said oxygen-lean zone being located between the lowermost fuel inlet level and the lowermost oxidant inlet level, between 50% and 100% by weight of the raw meal being supplied to the calciner upstream of and/or at the lowermost oxidant inlet level; and
the oxygen-lean zone distance Do is between 1/10 and 4/10 of the total calciner height.

3. The method of claim 1 , whereby at least part of the calciner oxidant is introduced into the calciner at the lowermost oxidant inlet level through a plurality of first calciner oxidant inlets, at least some of said first oxidant inlets being radially spaced apart from one another in the longitudinal direction of the calciner and/or around the longitudinal direction of the calciner.

4. The method of claim 1 , whereby the calciner oxidant is divided in a first and second portion, the first portion being introduced into the calciner at the lowermost oxidant inlet level through one or more first oxidant inlets, the second portion of the calciner oxidant being introduced into the calciner at one or more second oxidant levels downstream of the lowermost oxidant inlet level through one or more second oxidant inlets.

5. The method of claim 4 , whereby the second portion of the calciner oxidant is introduced into the calciner through more than one second oxidant inlet, at least some of said second oxidant inlets being spaced apart from one another in the longitudinal direction of the calciner and/or radially around the longitudinal direction of the calciner.

6. The method of claim 1 , whereby the recycle flue gas contains at least 40% by dry volume of CO2.

7. The method of claim 1 , whereby the recycle flue gas is introduced into the calciner at a temperature of at least 400° C.

8. The method of claim 1 , whereby the separated calciner flue gas is thereafter introduced in a raw meal preheater before part of the separated calciner flue gas is introduced into the calciner as the recycle flue gas.

9. The method of claim 1 , whereby a second part of the separated calciner flue gas is subjected to a gas purification process to extract constituents other than CO2 therefrom and is not introduced into the calciner as recycle flue gas.

10. The method of claim 9 , whereby following the gas purification process, the purified second part of the calciner flue gas is stored and/or used as CO2 in an industrial process.

11. The method of claim 1 , wherein:
the lowermost fuel inlet level is located at a fuel-lean zone distance Df>0 downstream of the lowermost oxidant inlet thereby creating a fuel-lean zone in the calciner between the lowermost oxidant inlet level and the lowermost fuel inlet level in which calciner oxidant is mixed with the recycled flue gas, between 50% and 100% by weight of the raw meal being supplied to the calciner upstream of and/or at the lowermost fuel inlet level; and
the fuel-lean zone distance Df is between 1/10 and 4/10 of the total calciner height.

Assignees

• Air Liquide
• Lafarge Sa

Inventors

• Panier Faustine
• Paubel Xavier
• Renna Carlo
• Gimenez Michel
• Paxton Colin
• Wassard Henrik
• Drivsholm Morten
• Tsiava Remi

Classifications

• C04B7/434 Primary

  Preheating with addition of fuel, e.g. calcining · CPC title

• C01B32/50

  Carbon dioxide · CPC title

• F27B7/2033

  with means for precalcining the raw material · CPC title

• F27B7/20

  Details, accessories or equipment specially adapted for rotary-drum furnaces · CPC title

• C04B2/10

  Preheating, burning calcining or cooling (decarbonation during burning of cement raw materials C04B7/43; {obtaining CaO or MgO otherwise than by thermal decomposition of the corresponding carbonates C01F11/02, C01F5/02}) · CPC title