Method and device for reprocessing wet waste materials containing organic components

Patent metadata

Field	Value
Publication number	US-9273904-B2
Application number	US-201214354028-A
Country	US
Kind code	B2
Filing date	Oct 18, 2012
Priority date	Oct 25, 2011
Publication date	Mar 1, 2016
Grant date	Mar 1, 2016

Abstract

In a method for reprocessing wet waste materials containing organic components, in particular sludges in a cement clinker production plant, in which raw meal is preheated in a preheater ( 3 ) in countercurrent flow to the hot exhaust gases of a clinker furnace ( 2 ), and calcined in a calciner ( 4 ) fired with alternative fuels, the wet waste materials are dried in a drying unit ( 18 ) using a hot gas produced from the preheater waste heat and the dried waste materials and the drier exhaust gases are discharged from the drying unit ( 18 ), wherein the drier exhaust gases are introduced into the calciner ( 4 ).

First claim

The invention claimed is:

1. A method for reprocessing wet waste materials containing organic components comprising sludges in a cement clinker production plant, wherein said method comprises preheating raw meal in a preheater in countercurrent flow to the hot exhaust gases of a clinker furnace, calcining in a calciner fired with alternative fuels, drying the wet waste materials in a drying unit using a hot gas produced from the preheater as waste heat, wherein the preheater waste heat is drawn off from the preheater in at least two different points of the preheater at two different temperature levels, so that at least two waste heat streams are created and the temperature of the hot gas which is fed to the drying unit is adjusted by selecting the mixing ratio of the waste heat streams, discharging the dried waste materials and the drier exhaust gases from the drying unit, and feeding the drier exhaust gases into the calciner.

2. The method according to claim 1 , wherein the drier exhaust gases are introduced into the calciner together with tertiary air.

3. The method according to claim 1 , wherein the drier exhaust gases are passed through the clinker cooler before they are introduced into the calciner.

4. The method according to claim 3 , wherein the drier exhaust gases are introduced into the clinker cooler at a point of the clinker cooler that is positioned vertically below the tertiary air extractor.

5. The method according to claim 1 , wherein the preheater comprises a plurality of preheater stages and the one waste heat stream is formed from hot gas that is tapped after the last preheater stage, and the other heat stream is formed from hot gas that is tapped at the outlet from an upstream preheater stage, particularly the first preheater stage.

6. The method according to claim 1 , wherein the hot gas streams diverted from the preheater are forwarded to a mixing cyclone, and the hot meal separated in the mixing cyclone is returned to the calciner or the raw meal.

7. The method according to any of claim 1 , wherein the hot gas supplied to the drying unit is at a temperature of 300-600° C.

8. The method according to claim 1 , wherein a partial quantity of the hot gas is drawn off before the drying unit and cooled in a heat exchanger with the drier exhaust gases, and that the cooled hot gas is forwarded to the drying unit as sealing gas.

9. The method according to claim 1 , wherein the drying unit is in the form of a grinding dryer.

10. A device for reprocessing wet waste materials containing organic components, in particular sludges in a cement clinker production plant, particularly for carrying out the method according to claim 1 , comprising a clinker furnace ( 2 ) with a clinker cooler ( 6 ) that is connected to the outlet end thereof, and with a calciner ( 4 ) and a preheater ( 3 ) arranged at the inlet end thereof, in which raw meal is preheated and calcined in countercurrent flow to the hot exhaust gases of the clinker furnace ( 2 ), and a drying unit ( 18 ) for the wet waste materials, which is connected to a hot gas line ( 20 ) that is supplied with waste heat from the preheater ( 3 ), and is followed by a separator ( 36 ) for separating the drier exhaust gases from the dried waste materials, characterised in that the separator ( 36 ) and the calciner ( 4 ) are in fluid communication with each other for the purpose of forwarding the drier exhaust gases to the calciner ( 4 ), and that the preheater ( 3 ) comprises at least two tapping points ( 21 , 26 ) arranged at a distance from one another in direction of flow for tapping hot gas via one branch line for each ( 22 , 27 ), that control elements ( 24 , 28 ), particularly sliders, are provided for adjusting the volume flows of the tapped hot gas, and that the hot gas streams are fed to a mixing device ( 25 ), the outlet opening of which is connected to the hot gas line ( 20 ).

11. The device according to claim 10 , wherein a segment of the fluid communication between the separator ( 36 ) and the calciner ( 4 ) is formed by a tertiary air duct ( 46 ), which links the tertiary air extractor ( 44 ) in the clinker cooler ( 6 ) with the calciner ( 4 ).

12. The device according to claim 11 , wherein the fluid communication between the separator ( 36 ) and the calciner ( 4 ) comprises a drier exhaust gas line ( 40 ) that opens into the clinker cooler ( 6 ).

13. The device according to claim 12 , wherein the drier exhaust gas line ( 40 ) opens into the clinker cooler ( 6 ) at a point below the tertiary air extractor ( 44 ).

14. The device according to claim 1 , wherein a temperature sensor ( 32 ) is provided for measuring the temperature of the hot gas ( 20 ) in the hot gas line, wherein the measured values of the temperature sensor ( 32 ) are transmitted to a controller ( 33 ) that cooperates with the control elements ( 24 , 28 ) to set a hot gas temperature from 300-600° C.

15. The device according to claim 1 , wherein the preheater ( 3 ) comprises a plurality of serially connected preheater stages ( 8 , 9 , 10 ), particularly gas suspension heat exchangers, and the one tapping point ( 26 ) is arranged after the last preheater stage ( 9 ) and the other tapping point ( 21 ) is arranged at the outlet from an upstream preheater stage, particularly the first preheater stage ( 8 ).

16. The device according to claim 1 , wherein the mixing device ( 25 ) is in the form of a mixing cyclone, from which the solid discharge ( 29 ) is connected to the calciner ( 4 ) or a raw meal infeed or transportation device ( 12 ) for the separated hot meal.

17. The device according to claim 9 , wherein a branch line ( 49 ) leads away from the hot gas line ( 20 ) to divert a partial flow of the hot gas, wherein the branch line opens into a heat exchanger ( 50 ) that can be charged with the drier exhaust gases, so that the branched hot gas can be cooled with the drier exhaust gases, and wherein a line for supplying the cooled hot gas to sealing gas ports ( 51 ) of the drier unit ( 18 ) is connected to the heat exchanger ( 50 ).

18. The device according to claim 9 , wherein the drier unit ( 18 ) is in the form of a grinding dryer.

19. The device according to any of claim 9 , wherein curtain walls ( 45 ) are arranged in the clinker cooler ( 6 ) upstream and downstream of the point at which the drying gas line ( 40 ) opens into the clinker cooler ( 6 ) in the direction of movement of the clinker.

20. A method according to claim 1 , wherein the hot dry gas supplied to the drying unit is at a temperature of 500-600° C.

Assignees

• Holcim Technology Ltd
• Holcim Technology Ltd

Inventors

• Gasser Urs

Classifications

• F27D17/10

  Arrangements for using waste heat · CPC title

• F27D17/20

  Arrangements for treatment or cleaning of waste gases · CPC title

• F23G2900/50211

  Evaporating, e.g. liquid waste before burning · CPC title

• F23G2206/201

  with an industrial furnace · CPC title

• F23G7/001

  for sludges or waste products from water treatment installations (F23G5/008 takes precedence) · CPC title