CN-121990598-A - Zero-carbon-emission aluminum hydroxide roasting system

CN121990598ACN 121990598 ACN121990598 ACN 121990598ACN-121990598-A

Abstract

The invention discloses a zero-carbon-emission aluminum hydroxide roasting system, which relates to the technical field of aluminum hydroxide roasting, wherein aluminum hydroxide materials enter a drying unit through a feeding device, exchange heat with dust removal recovery flue gas and high-temperature flue gas generated by a secondary preheater, the dried materials enter a roasting furnace after sequentially entering a primary preheater, a secondary preheater and a tertiary preheater, enter a four-stage preheater for gas-solid separation after the materials are roasted, enter a suspension reactor, enter a multi-stage cooling unit for multi-stage cooling, and the cooled materials enter a solid-solid heat exchanger to obtain finished aluminum oxide. The invention realizes the full-process secondary utilization of the heat of the flue gas and the finished product materials through the cooperative design of the multi-stage preheating unit, the drying unit, the solid-solid heat exchanger and the steam recovery device, takes hydrogen as the only fuel, takes the hydrogen combustion product as water, and completely eradicates the emission of CO2 and NO x pollutants generated by the combustion of the traditional fossil fuel from the source.

Inventors

CAO WANQIU
SHAN TIANLONG
YIN DEMING
CHEN GUOHUA
LI ZHIGUO
WANG XUEYONG
SUN SHENGREN
CAO YUHANG
WANG YI
WANG XIAOYU

Assignees

沈阳铝镁设计研究院有限公司

Dates

Publication Date: 20260508
Application Date: 20260204

Claims (10)

1. The aluminum hydroxide roasting system with zero carbon emission is characterized by comprising a feeding device, a drying unit, a multi-stage preheating unit, a roasting furnace, a multi-stage cooling unit, a suspension reactor and a dust removal recovery unit, wherein the multi-stage preheating unit comprises a one-stage preheater to a four-stage preheater; The aluminum hydroxide material enters a drying unit through a feeding device, exchanges heat with high-temperature flue gas recovered by a dust removal recovery unit and generated by a secondary preheater, the heat exchanged material sequentially enters a primary preheater, a secondary preheater and a tertiary preheater, then enters a roasting furnace, the material enters a four-stage preheater for gas-solid separation, then enters a suspension reactor, the material subjected to high-temperature suspension reaction enters a multi-stage cooling unit for multi-stage cooling, the cooled material enters a solid-solid heat exchanger to obtain finished aluminum oxide, and the finished aluminum oxide and soft water indirectly exchange heat and are cooled and then enter a receiving device below.
2. The zero-carbon-emission aluminum hydroxide roasting system as claimed in claim 1, wherein the drying unit comprises a hydrate dryer and a dryer connected with a discharge hole of the hydrate dryer, high-temperature flue gas from an outlet of the steam recovery device is introduced into the hydrate dryer, the high-temperature flue gas passes through the hydrate dryer and is connected to an air inlet pipeline of the primary preheater, the material is primarily dried by the hydrate dryer and then enters the dryer for re-drying, and the material passing through the dryer is sent to the primary preheater.
3. The zero-carbon-emission aluminum hydroxide roasting system as claimed in claim 2, wherein the high-temperature flue gas at the outlet of the steam recovery device is conveyed to the hydrate dryer through a fan, and a flue gas flow regulating valve is arranged on a connecting pipeline between the fan and the hydrate dryer.
4. The zero-carbon-emission aluminum hydroxide roasting system as claimed in claim 1, wherein high-temperature flue gas and materials are subjected to gas-solid separation in the primary preheater, the high-temperature flue gas enters a dust remover, collected dust is sent to the secondary preheater, the dust-removed flue gas enters a steam recovery device, a part of the flue gas enters a drying unit, and a part of the flue gas enters a smoke exhaust pipeline.
5. The zero-carbon-emission aluminum hydroxide roasting system as claimed in claim 1, wherein the discharge port of the primary preheater and the air outlet of the tertiary preheater are both communicated with the secondary preheater, the air outlet of the secondary preheater is communicated with the drying unit, the discharge port of the secondary preheater and the air outlet of the quaternary preheater are communicated with the tertiary preheater, the discharge port of the tertiary preheater is connected with the roasting furnace, and the discharge port of the roasting furnace is connected with the quaternary preheater.
6. The zero-carbon-emission aluminum hydroxide roasting system as claimed in claim 1, wherein the roasting furnace is provided with a hydrogen nozzle communicated with hydrogen in both the conical section and the straight section, a hydrogen flow regulating valve is arranged on a hydrogen pipeline, an air inlet below the roasting furnace is communicated with a high-temperature air outlet of the solid-solid heat exchanger, and an air flow regulating valve is arranged on a connecting pipeline.
7. The aluminum hydroxide roasting system with zero carbon emission as claimed in claim 1, wherein the discharge port of the four-stage preheater is connected to a suspension reactor, a fluidization air inlet is arranged at the lower part of the suspension reactor, high-temperature air generated after air passes through the solid-solid heat exchanger is communicated with the fluidization air inlet, and the discharge port of the suspension reactor is connected to a multi-stage cooling unit.
8. The aluminum hydroxide roasting system with zero carbon emission of claim 1, wherein the solid-solid heat exchanger is provided with a feed inlet, a discharge outlet, a soft water inlet, a high-temperature high-pressure steam outlet, an air inlet and a high-temperature air outlet.
9. The aluminum hydroxide roasting system with zero carbon emission according to claim 1, wherein the multistage cooling unit comprises a primary cooler and a secondary cooler, the materials passing through the suspension reactor sequentially enter the primary cooler and the secondary cooler for cooling and then enter the solid-solid heat exchanger, the materials indirectly exchange heat with soft water in the solid-solid heat exchanger and then enter the receiving device, and steam generated in the solid-solid heat exchanger is discharged through a high-temperature high-pressure steam outlet of the solid-solid heat exchanger.
10. The aluminum hydroxide roasting system with zero carbon emission as claimed in claim 9, wherein the discharge port of the primary cooler is communicated with air to the secondary cooler, the air outlet of the primary cooler is communicated with the air inlet of the roasting furnace, and the air outlet of the secondary cooler is communicated with the air inlet of the primary cooler.

Description

Zero-carbon-emission aluminum hydroxide roasting system Technical Field The invention relates to the technical field of aluminum hydroxide roasting, in particular to a zero-carbon-emission aluminum hydroxide roasting system. Background The roasting of aluminum hydroxide is a key process in the production flow of aluminum oxide, and the key function of the roasting is to remove crystal water from aluminum hydroxide and complete crystal form conversion by high-temperature heating, so that an aluminum oxide product meeting the industrial standard is finally produced. The energy consumption level and pollutant emission intensity of the process directly determine the overall environmental protection level, economic cost and market competitiveness of alumina production, and the process is a core management and control link for alumina enterprises to realize green low-carbon development. Currently, the main stream of domestic alumina enterprises adopts equipment such as a gaseous suspension roasting furnace, a rotary kiln and the like to carry out roasting operation, the heat supply mode of the equipment still highly depends on fossil fuels such as natural gas, heavy oil and the like, and the equipment has a single energy structure and high carbon emission intensity. On one hand, the conventional fossil fuel roasting process inevitably generates a large amount of carbon dioxide in the fossil fuel combustion process, zero carbon emission in the roasting process cannot be realized, the long-term dependence on fossil fuel is easily influenced by energy price fluctuation, and the production operation cost is increased, on the other hand, the fossil fuel combustion process is accompanied with the generation of pollutants such as nitrogen oxides (NO x), and the like, so that the tail gas treatment equipment and the cost are additionally input, the environment-friendly standard reaching risk exists, and the green development progress of enterprises is restricted. Hydrogen is taken as an ideal clean fuel, has the remarkable advantages of only water as combustion products, zero carbon dioxide emission, high flame speed and high calorific value, can completely eradicate carbon emission in the roasting process from the source, perfectly meets the green low-carbon transformation requirement of the alumina industry, and provides a brand new technical path for zero carbon upgrading of the aluminum hydroxide roasting process. In the process of roasting aluminum hydroxide, a large amount of high-temperature flue gas and high-temperature alumina products can be generated, while the prior art is provided with a basic preheating and cooling heat exchange device, the heat recovery efficiency is limited, a large amount of waste heat is directly dissipated, the cascade secondary utilization of the heat cannot be realized, and the energy consumption of the system is further increased. Disclosure of Invention In view of the above disadvantages and shortcomings, the invention provides a zero-carbon-emission aluminum hydroxide roasting system, which realizes the full-process secondary utilization of heat of flue gas and finished products by the cooperative design of a multi-stage preheating unit, a drying unit, a solid-solid heat exchanger and a steam recovery device, takes hydrogen as the only fuel, takes a hydrogen combustion product as water, and eliminates the emission of CO 2 and NO x pollutants generated by the combustion of traditional fossil fuels from the source. In order to achieve the aim, the aluminum hydroxide roasting system with zero carbon emission comprises a feeding device, a drying unit, a multi-stage preheating unit, a roasting furnace, a multi-stage cooling unit, a suspension reactor and a dust removal recovery unit, wherein the multi-stage preheating unit comprises a one-stage preheater to a four-stage preheater; The aluminum hydroxide material enters a drying unit through a feeding device, exchanges heat with high-temperature flue gas recovered by a dust removal recovery unit and generated by a secondary preheater, the heat exchanged material sequentially enters a primary preheater, a secondary preheater and a tertiary preheater, then enters a roasting furnace, the material enters a four-stage preheater for gas-solid separation, then enters a suspension reactor, the material subjected to high-temperature suspension reaction enters a multi-stage cooling unit for multi-stage cooling, the cooled material enters a solid-solid heat exchanger to obtain finished aluminum oxide, and the finished aluminum oxide and soft water indirectly exchange heat and are cooled and then enter a receiving device below. The drying unit comprises a hydrate dryer, a dryer connected with a discharge hole of the hydrate dryer, high-temperature flue gas from an outlet of the steam recovery device is introduced into the hydrate dryer, the high-temperature flue gas passes through the hydrate dryer and is connected to an air inlet pipeline of the p