Blast furnace slag granulation and waste heat recovery and utilization device and method

Patent metadata

Field	Value
Publication number	US-2023100959-A1
Application number	US-202017802605-A
Country	US
Kind code	A1
Filing date	Dec 31, 2020
Priority date	Feb 28, 2020
Publication date	Mar 30, 2023
Grant date	—

Abstract

Disclosed are an apparatus and a method for granulation of a blast furnace slag and recycling of waste heat. The apparatus comprises an aerosol granulation nozzle module, a flow guide, a cyclone separator and a waste heat recovery device; wherein the aerosol granulation nozzle module comprises a slag flow controller, a compressed air flow control valve, a water volume control valve and an aerosol spray gun; the flow guide is configured to fully mix the medium temperature gas and the high-temperature granular slag having a primarily solidified surface in the flow guide; and the cyclone separator is configured to separate the high-temperature granular slag and the medium-to-high-temperature gas. The present invention completes the granulation of blast furnace slag, and organically couples slag sensible heat recovery with sludge drying, thereby recovering the waste heat in the process of slag granulation and improving the efficiency of waste heat recovery and utilization.

First claim

1 . An apparatus for granulation of a blast furnace slag and recycling of waste heat, wherein the apparatus comprises an aerosol granulation nozzle module, a flow guide ( 7 ), a cyclone separator ( 8 ) and a waste heat recovery device;
wherein the aerosol granulation nozzle module comprises a slag flow controller ( 2 ), a compressed air flow control valve ( 3 ), a water volume control valve ( 4 ) and an aerosol spray gun ( 5 ); wherein the slag flow controller ( 2 ) is coupled to a slag inlet of the flow guide ( 7 ); the compressed air flow control valve ( 3 ) is coupled to a gas inlet of the aerosol spray gun ( 5 ); the water volume control valve ( 4 ) is coupled to a liquid inlet of the aerosol spray gun ( 5 ); wherein a nozzle of the aerosol spray gun ( 5 ) is configured to face an inlet of the flow guide ( 7 ) to enable an aerosol to impinge a slag stream entering the flow guide ( 7 ) through the slag flow controller ( 2 ) to form a medium-temperature gas and a high-temperature granular slag ( 6 ) having a primarily solidified surface; wherein the flow guide ( 7 ) is configured to fully mix the medium-temperature gas and the high-temperature granular slag ( 6 ) having a primarily solidified surface in the flow guide, wherein an outlet of the flow guide ( 7 ) is coupled to a feed port of the cyclone separator ( 8 ) to allow for entry of a completely solidified high-temperature granular slag ( 6 ) and a medium-to-high-temperature gas formed in the flow guide ( 7 ) into the cyclone separator ( 8 ); wherein the cyclone separator ( 8 ) is configured to separate the high-temperature granular slag ( 6 ) and the medium-to-high-temperature gas; wherein a discharge port of the cyclone separator ( 8 ) is coupled to a feed port of the waste heat recovery device for delivery of the medium-to-high-temperature gas and the completely solidified high-temperature granular slag ( 6 ) to the waste heat recovery device.

2 . The apparatus for granulation of a blast furnace slag and recycling of waste heat according to claim 1 , wherein a slag stream ( 1 ) is subjected to flow control by the slag flow controller ( 2 ) and flows into a slag inlet of the flow guide ( 7 ); a high pressure gas is directed to the gas inlet of the aerosol spray gun ( 5 ) through the compressed air flow control valve ( 3 ); water is directed to the liquid inlet of the aerosol spray gun ( 5 ) through the water volume control valve ( 4 ); wherein the nozzle of the aerosol spray gun ( 5 ) is configured to face the inlet of the flow guide ( 7 ) to enable an aerosol to impinge the slag stream ( 1 ) to form a medium-temperature gas and a high-temperature granular slag ( 6 ) having a primarily solidified surface.

3 . The apparatus for granulation of a blast furnace slag and recycling of waste heat according to claim 1 , wherein after formed by impinging the aerosol from the aerosol granulation nozzle module on the slag stream ( 1 ), the medium-temperature gas has a temperature of 200-400° C., and the high-temperature granular slag ( 6 ) having a preliminarily solidified surface has a temperature of 1000-1200° C.; wherein after mixed in the flow guide ( 7 ), the medium-to-high temperature gas has a temperature of 300-500° C., and the completely solidified high-temperature granular slag ( 6 ) has a temperature of 800-1100° C.; wherein after separated by the cyclone separator ( 8 ), the high-temperature granular slag ( 6 ) has a temperature of 700-950° C., and the medium-to-high temperature gas has a temperature of 350-550° C.

4 . The apparatus for granulation of a blast furnace slag and recycling of waste heat according to claim 1 , wherein the waste heat recovery device is a sludge drying module comprising a screw mixer ( 9 ), a sludge dryer ( 10 ), a sludge pre-drying module, a slag-sludge recovery module and a tail gas treatment module; wherein the discharge port of the cyclone separator ( 8 ) is coupled to a first feed port of the screw mixer ( 9 ) to transport the completely solidified high-temperature granular slag ( 6 ) into the screw mixer ( 9 ); wherein an aerosol port of the cyclone separator ( 8 ) is coupled to an aerosol port of the sludge pre-drying module to transport the medium-to-high-temperature gas into the sludge pre-drying module, so that the medium-to-high-temperature gas is mixed with a wet sludge in the sludge pre-drying module to form a semi-dry sludge; wherein a discharge port of the sludge pre-drying module is coupled to a second feed port of the screw mixer ( 9 ) to transport the semi-dry sludge into the screw mixer ( 9 ), so that the semi-dry sludge and the high-temperature granular slag ( 6 ) are mixed in the screw mixer ( 9 ) to form a slag-sludge mixture; wherein a discharge port of the screw mixer ( 9 ) is coupled to a feed port of the sludge dryer ( 10 ) to transport the slag-sludge mixture into the sludge dryer ( 10 ); wherein a discharge port of the sludge dryer ( 10 ) is coupled to a feed port of the slag-sludge recovery module to transport a dry sludge powder and slag granules into the slag-sludge recovery module; wherein a gas inlet of the tail gas treatment module is coupled to a gas outlet of the sludge pre-drying module, a gas outlet of the sludge dryer ( 10 ) and a gas outlet of the slag-sludge recovery module.

5 . The apparatus for granulation of a blast furnace slag and recycling of waste heat according to claim 1 , wherein the waste heat recovery device is a high-temperature steam preparation module, wherein the high-temperature steam preparation module is coupled to the cyclone separator ( 8 ) to recover heat of the medium-to-high-temperature gas and the high-temperature granular slag ( 6 ) to prepare a high-temperature steam having a temperature of 200-250° C.; wherein a tail gas outlet of the high-temperature steam preparation module is coupled to a tail gas treatment module.

6 . The apparatus for granulation of a blast furnace slag and recycling of waste heat according to claim 5 , wherein the high-temperature steam preparation module comprises a slag bin ( 11 ), a tail gas treatment device ( 17 ), a gas purifier ( 18 ), an exhauster ( 19 ), a chimney ( 20 ), a high-temperature feed conveyor ( 21 ), a high-temperature granular slag heat exchanger ( 22 ), a boiler ( 23 ) and an economizer ( 24 );
wherein the high-temperature feed conveyor ( 21 ) is provided between the discharge port of the cyclone separator ( 8 ) and a feed port of the high-temperature granular slag heat exchanger ( 22 ) to transport the high-temperature granular slag ( 6 ) separated by the cyclone separator ( 8 ) to an upper part of the high-temperature granular slag heat exchanger ( 22 ); a coil containing circulating water is provided in the high-temperature granular slag heat exchanger ( 22 ) for reverse heat exchange of the coil and a gas stream rising from bottom to top with the high-temperature granular slag ( 6 ); the slag bin ( 11 ) is provided under a discharge port located at a bottom of the high-temperature granular slag heat exchanger ( 22 ) to receive the granular slag after cooling; a top of the high-temperature granular slag heat exchanger ( 22 ) is provided with a gas port which is coupled to the boiler ( 23 ); the economizer ( 24 ) is coupled to the boiler ( 23 ) and the high-temperature granular slag heat exchanger ( 22 ) respectively, so that pure water sent to the economizer ( 24 ) through an external pipe network is preheated to 80° C. or higher by a tail gas emitted from the boiler ( 23 ), and divided into two parts, one part being sent into the boiler ( 23 ), and the other part entering the coil of the high-temperature granular slag heat exchanger ( 22 ) to absorb heat of the high-temperature granular slag ( 6 ); wherein a gas inlet of the tail gas treatment device ( 17 ) is coupled to a tail gas outlet of the economizer ( 24 ), a gas outle

Assignees

• Baoshan Iron & Steel

Inventors

• Xiao Yongli
• Li Yongqian
• Zhang Youping
• Guan Yunze
• Xie Mengqin
• Wang Yingjie

Classifications

• F01K25/14

  using industrial or other waste gases · CPC title

• C21B2400/08

  with energy recovery · CPC title

• C21B2400/062

  Jet nozzles or pressurised fluids for cooling, fragmenting or atomising slag · CPC title

• Y02P10/25

  Process efficiency · CPC title

• F27D17/00

  Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases · CPC title