Low NOx calciner

Patent metadata

Field	Value
Publication number	US-10974992-B2
Application number	US-201816643190-A
Country	US
Kind code	B2
Filing date	Aug 29, 2018
Priority date	Aug 30, 2017
Publication date	Apr 13, 2021
Grant date	Apr 13, 2021

Abstract

A system for reducing NOx emission levels during the manufacture of cement clinker having a calciner unit with the following features: an upper portion; a lower portion; a NOx reduction zone in the lower portion; a tertiary air inlet in the upper portion for introducing tertiary air into the upper portion; a main calciner meal inlet located above the NOx reduction zone for introducing a main calciner meal portion into the upper portion; a first cooling calciner meal inlet located in the NOx reduction zone for introducing a first cooling calciner meal portion into a periphery of the NOx reduction zone; and a fuel inlet located in or below the NOx reduction zone for introducing fuel into the reduction zone.

First claim

The invention claimed is:

1. A system for reducing NO x emission levels during the manufacture of cement clinker comprising a calciner unit further comprising:
an upper portion;
a lower portion;
a NO x reduction zone in the lower portion having a refractory layer on the inside surface thereof;
a tertiary air inlet in the upper portion for introducing tertiary air into the upper portion;
a main calciner meal inlet located above the NO x reduction zone for introducing a main calciner meal portion into the upper portion;
a first cooling calciner meal inlet located in the NO x reduction zone for introducing a first cooling calciner meal portion into a periphery of the NO x reduction zone for forming a peripheral layer of meal in the NO x reduction zone for protecting the refractory layer from hot kiln gas;
a second cooling calciner meal inlet located in the NO x reduction zone;
a fuel inlet located in or below the NO x reduction zone for introducing fuel into the NO x reduction zone for supporting a hot core of the hot kiln gas within the peripheral layer of the meal in the NO x reduction zone;
wherein the first or second cooling calciner meal inlets located in the NO x reduction zone are arranged such that the cooling calciner meal portion is introduced tangentially into the NO x reduction zone; and
a constriction located between the upper portion and lower portion for inhibiting the main calciner meal portion in the upper portion from entering the NO x reduction zone.

2. The system of claim 1 , wherein the main calciner meal inlet is located above the tertiary air inlet.

3. The system of claim 1 , further comprising a riser unit located below the NO x reduction zone wherein the fuel inlet is located below the NO x reduction zone in the riser unit.

4. The system of claim 3 , wherein a cross-sectional area of the NO x reduction zone is larger than a cross-sectional area of the riser unit.

5. The system of claim 1 , wherein the NO x reduction zone comprises a reduction zone inlet cone and wherein the fuel inlet is located immediately adjacent to and below the inlet cone.

6. The system of claim 1 , wherein the second cooling calciner meal inlet is positioned laterally opposite the first cooling calciner meal inlet for introducing a second cooling calciner meal portion into the periphery of the NO x reduction zone forming a peripheral layer of the meal in the NO x reduction zone for further protecting the refractory layer from the hot kiln gas.

Assignees

• Smidth As F L

Inventors

• Grévain Damien
• Nielsen Mads

Classifications

• F27B7/205

  with precalcining means on the string supplied with exhaust gases from the cooler · CPC title

• F27B7/2033 Primary

  with means for precalcining the raw material · CPC title

• C04B7/364 Primary

  Avoiding environmental pollution during cement-manufacturing · CPC title

• F27B1/005

  wherein no smelting of the charge occurs, e.g. calcining or sintering furnaces · CPC title

• C04B7/4469

  in shaft or vertical kilns · CPC title