US 4,392,890 A · Cement clinker production

Abstract

Cement clinker is produced from cold, dry, finely divided raw material by causing hot flue gases to flow in a first direction out of a rotary kiln and suspending a major portion of the finely divided raw material in the hot flue gases until the raw material has been preheated and at least partially decarbonized. The preheated and at least partially decarbonized raw material is introduced into the kiln. A fraction of the cold, dry, finely divided raw material is pneumatically injected into an end of the kiln to flow countercurrently to said first direction approximately parallel to the axis of the kiln to form a dust cloud of the raw material occupying substantially the entire cross section of the kiln at said end, the end being upstream with respect to a second direction of flow of the raw material into the kiln.

Claims12

Dependent claims

A method of producing cement clinker from cold, dry, finely divided raw material, which comprises the steps of

(a) causing hot flue gases to flow in a first direction out of a rotary kiln having an axis,
(b) suspending a major portion of the finely divided raw material in the hot flue gases until the raw material has been preheated and at least partially decarbonized,
(c) introducing the preheated and at least partially decarbonized raw material into the kiln, and
(d) pneumatically injecting a fraction of the cold, dry, finely divided raw material into an end of the kiln and countercurrently to said first direction approximately parallel to the axis of the kiln to form a dust cloud of the raw material occupying substantially the entire cross section of the kiln at said end, the end being upstream with respect to a second direction of flow of the raw material into the kiln.

1 more element

An installation for producing cement clinker from a cold, dry, finely divided raw material, which comprises

(a) a rotary kiln having an axis and an upstream end,
(b) a casing defining a smoke chamber at the upstream end and receiving hot flue gases from the kiln flowing in a first direction,
(c) a multi-stage heat exchanger having a last stage and arranged to receive a major portion of the finely divided raw material flowing therethrough to the last stage,
(d) a flue connecting the smoke chamber to the last heat exchanger stage and directing the flue gases into the heat exchanger for suspending the major portion of the raw material therein until it has been preheated and at least partially decarbonized,
(e) means for introducing the preheated and at least partially decarbonized raw material into the kiln, and,
(f) a pneumatic injection nozzle mounted in the casing, extending substantially parallel to the kiln axis and directed towards the upstream kiln end for injecting a fraction of the cold, dry, finely divided raw material through the upstream end into the kiln to form a dust cloud of the raw material occupying substantially the entire cross section of the kiln at said end.

3 more elements

Dependencies are inferred from the claim text.

Cement clinker production

Life of this patent

Cement clinker production

Life of this patent

Abstract

Claims12