WO2004055264A1

WO2004055264A1 - System and method for utilizing the heat of smelting fume in papermaking and eliminating the pollution of black lye and the exhaust gas and residue of smelting

Info

Publication number: WO2004055264A1
Application number: PCT/CN2003/001073
Authority: WO
Inventors: Shujun Liu
Original assignee: Shujun Liu
Priority date: 2002-12-17
Filing date: 2003-12-16
Publication date: 2004-07-01
Also published as: AU2003292853A1; CN2599049Y

Abstract

This invention relates a method and a system for utilizing the heat of smelting fume in papermaking and eliminating the pollution of the black lye and the exhaust gas and residue of smelting. The system includes: an evaporator, with a fume inlet and a residue outlet on its downside and a black lye inlet and a vent on its upside; a boiler, laying on the upside of the evaporator and contacting its body completely with the entering fume; a condenser, connecting with the evaporator vent and a precipitator; a precipitator, where condensated water enters; a water-pressing pool, where the black lye in the paper pulp from the boiler be pressed out by the rinsing to yield the pulp; and a black lye pool, where the black lye from the water-pressing pool be pumped to the black lye inlet of the evaporator. In this system the black lye react with the fume and yield the residues and the mixture of gases, then the mixture of gases is condensed in the condenser and the resulted water flow into the precipitator, then the resulted rinsing from precipitator being recovered to the static-pressure of papermaking and the resulted black lye flowing into the black lye pool and being pumped into the evaporator, thus one circle is accomplished. The residue of smelting mixes and react with lime in a caustic pool, then the resulted sodium hydroxide being recovered to papermaking and the resulted gypsum mixing with grid and asbestos of the exhausted batteries to being pavior. According to the invention, the cost of eliminating pollution is decreased largely, thus the aim of treating waste with waste and making the let of waste be zero can be realized.

Description

Method and system for removing papermaking black liquor and smelting waste gas waste residue by using smelting waste heat paper

Technical field

A "" month relates to a method and a system for removing pollution from black liquor generated during the papermaking process and pollution from waste gas and slag generated during the smelting process by using waste heat papermaking smelting, and particularly relates to neutralizing the black liquor generated from papermaking by the soot and exhaust gas discharged from the smelting furnace, In order to achieve the method and system of eliminating smelting soot pollution, eliminating papermaking black liquor pollution, and utilizing the waste heat of soot and dust. Background technique

Papermaking black liquor and smelting soot have great harm to the environment. Direct emissions can cause severe environmental pollution. At present, the papermaking black liquor is treated by alkali recovery chemicals or thorium recovery processing, but the recycling project has a large investment, high energy consumption, and high operating costs. The smelting (waste lead storage battery) flue gas components are mainly waste sulfuric acid and metal fly ash, such as: lead fly ash, sulfur dioxide, various impurity particles and dust and a large amount of heat energy. The currently used bag dust removal method not only has high equipment cost, but also reduces flying dust, which cannot be treated with sulfur dioxide. Disclosure of invention

The purpose of the present invention is to disclose a method and a system for removing papermaking black liquor and smelting waste gas residues by using smelting waste heat for papermaking, to solve the environmental pollution caused by the above-mentioned papermaking and smelting furnaces, and proposing a method for utilizing soot discharged from smelting furnaces to neutralize papermaking The black liquor generated in the process can also use the waste heat of the discharged soot to make energy for papermaking, in order to achieve the comprehensive benefits of energy saving, pollution control and ecological environment protection.

Another object of the present invention is to recover the waste residue produced by the method and system of the present invention to produce gypsum and other materials, so as to achieve the full utilization of resources.

The technical solutions adopted by the present invention to solve the technical problems are: 1. The method of the present invention has the following process flow:

1. The paper black liquor is sent to the evaporator, and at the same time, the smelting flue gas enters the evaporator, and the two are mixed to form. The sediment and the harmless gas are evaporated and discharged;

2. The mixed gas from the evaporator is condensed by the condensation tower to generate an aqueous solution and discharged into the precipitation tank;

3. The clear water precipitated in the sedimentation tank is recovered for papermaking and black liquor, and the produced black liquor is sent to the evaporator to complete a cycle.

4. The sediment produced in step 1 is calcined in a reflection furnace to produce carbon monoxide and carbon dioxide, and a mixed waste residue of sodium sulfate and sodium carbonate is formed in the upper layer, and recyclable metals such as lead and antimony are used in the lower layer.

5. The mixed waste slag of sodium sulfate and sodium carbonate generated in the above step 4 enters the pool together with the clear water in the precipitation tank, and then adds caustic reaction such as lime to generate calcium sulfate (gypsum), calcium sulfite sediment, and hydrogen. Aqueous sodium oxide solution can be recycled for papermaking.

6. Calcium sulfate and calcium sulfite residues remaining in the causticizing reaction from step 5 above are neutralized with sulfuric acid in a battery, and are neutral.

7. The sediment produced in step 6 above can be used as a paving substrate or as a raw material for a cement plant. Since most calcium sulfate (gypsum), calcium sulfite, calcium carbonate reacts with air to calcify to stone, it is difficult for residual metals It dissolves in water and enters the atmosphere, thus ensuring no pollution. Second, the system of the present invention

In order to realize the steps of the above invention, the system for eliminating pollution of black liquor in papermaking and pollution of smelting waste gas of the present invention includes cooking equipment, cooling tower, sedimentation tank, static pressure tank and black liquor tank, which is further characterized by: an evaporator, The lower part is provided with a dust inlet and a waste discharge outlet, and the upper part is provided with a black liquid inlet and an exhaust outlet; a flue, the flue gas discharged from the smelting furnace passes through the flue of the smelting furnace, and enters the evaporator from the fume inlet of the evaporator; The cooking equipment is a cooking device located on an evaporator, and its pot body is in full contact with the smoke and dust entering the evaporator; the sedimentation tank has the function of storing condensed water and sedimentary clear water, and the black liquid in the black liquid tank passes pressure The pump is pressurized to enter the evaporator from the black liquid inlet; the cooling tower is respectively connected to the exhaust port of the evaporator and the precipitation tank, and the gas from the evaporator is cooled and condensed into a liquid into the precipitation tank.

The system for eliminating the pollution of black liquor of papermaking and the pollution of exhaust gas of the invention can be provided with a pipe and a pressure pump between the black liquor inlet of the evaporator and the black liquor tank outlet, and the nozzle at the black liquor inlet can make the black liquor entering the evaporator The liquid was sprayed in a mist.

Compared with the prior art, the beneficial effects of the present invention are:

1. Investment in fixed assets for pollution control, including plant and equipment, has been significantly reduced. There is no need to use expensive heat-resistant cloth bags, and no stainless steel equipment is needed.

2. The present invention treats waste by waste, and the wastes are mutually utilized. The residual alkali in the papermaking black liquor is the solvent for smelting lead. The organic matter in the papermaking black liquor is calcined to form carbon monoxide, and it is a reducing agent for smelting lead. At the same time, the causticizing reaction can be further used to generate alkali that can be recycled as a raw material for papermaking.

3. By implementing the method of the present invention, zero emissions of papermaking and smelting industry can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the overall structure of a system for removing pollution from papermaking black liquor and smelting waste gas residues by using smelting waste heat for papermaking according to the present invention;

In the picture

1 smelting furnace 10 row nozzle

2.Flue 11 black liquor outlet

3.Exhaust port 12 sedimentation tank 4 Evaporator 3 Fresh water outlet

Flue gas inlet 4 cooling tower

8 black liquor inlet 7 causticizing;

9 pressure pump

Best way to implement the invention

The following uses the smelting waste heat papermaking method of the present invention to remove papermaking black liquor and smelting waste gas waste in accordance with the accompanying drawings

'Slag contamination systems and methods are described in detail. '

1. The papermaking black liquor stored in the black liquor tank 16 is sent to the evaporator 4 through the black liquor inlet 8 provided on the evaporator 4 through the pressure pump 9; at the same time, the smelting flue gas in the smelting furnace 1 goes down the flue 2 After entering the evaporator 4, both the papermaking black liquor and the smelting flue gas are mixed in the evaporator 4, and the generated slag is discharged and discharged at the discharge port 10, and the generated mixed gas is evaporated and discharged through the exhaust port 3.

The sediment discharged from the discharge port 10 includes sodium hydroxide, sodium sulfate, sodium sulfite, coal dust, metal dust such as lead, antimony, and metal oxide dust. The mixed gas contains sodium sulfate, sodium sulfite, and sodium hydroxide.

2. The mixed gas from the evaporator 4 enters the condensing tower 14. Part of the mixed gas is condensed by the condensing tower 14 to form an aqueous solution and discharged into the precipitation tank 12. The other part of the gas conforming to the discharge standard is discharged from the exhaust port of the condensing tower 14.

3. The clear water precipitated in the lake 12 is recovered into the static pressure pool 15 and used to statically press the black liquor for papermaking. The generated black liquor is sent to the black liquor pool 16 and is ready to be transported from the black liquor pool 16 to the evaporator 4 at any time. To complete a cycle.

4. The slag generated in step 1 is mixed with metal oxides (smelting raw materials) in proportion, and then calcined in a reverberatory furnace to produce carbon monoxide and carbon dioxide, and a mixed waste slag with sodium sulfate and sodium carbonate in the upper layer and lead that is recyclable in the lower layer. , Antimony.

5. The mixed waste slag of sodium sulfate and sodium carbonate generated in the above step 4 enters the causticizing tank 17 together with the clear water in the precipitation tank 12, and the lime is added for causticizing reaction to generate calcium sulfate (gypsum), calcium sulfite sediment, and generated hydrogen. The sodium oxide aqueous solution can be recovered and added to the digester 7 for papermaking.

6. In step 5 above, the causticizing reaction in the causticizing tank 17 is left with residual sodium hydroxide, calcium sulfate, and calcium sulphite, which is neutralized with sulfuric acid in a waste battery. It is neutral and is used for sale to a cement plant as Raw materials.

7. The sediment generated in step 6 above is mixed with the grid and asbestos in the waste battery as the paving substrate. Because most calcium sulfate (gypsum), calcium sulfite, calcium carbonate reacts with air to calcify into stones, the residual metals are difficult to dissolve in water and enter the atmosphere, thereby ensuring no pollution. FIG. 1 is an overall schematic diagram of a system for removing pollution from papermaking black liquor and smelting waste gas residues by using smelting waste heat paper in the present invention. As shown in FIG. 1, the system of this embodiment includes an evaporator 4 and a cooker 7. The cooker 7 is installed above the interior of the evaporator 4, and a flue gas inlet 5 is provided at the bottom of the evaporator 4, and the flue 2 enters the evaporator 4. Smoke and dust contain a large amount of thermal energy, the main component is waste sulfuric acid, containing metallic fly dust including lead, sulfur dioxide, various impurity particles, etc .; the upper part of the evaporator 4 is provided with a black liquor inlet 8, and the black liquor for paper making passes through the pump through this pump. 9 Pressurized into the evaporator 4 and sprayed from the top of the device; with the same progress, the smelting flue gas enters the evaporator 4 and is sprayed from the bottom to the top. The bottom of the boiler 7 and the smelting flue are in full contact to heat Exchange, use the waste heat to cook the paper paddle, the black liquor of the papermaking and the smelting flue gas are fully mixed, and the sediment is generated and the mixed gas is evaporated and discharged. After cooling, the water (salt-containing liquid) is sent out and evacuated to harmless gas.

The components of the black liquor are alkali and organic matter in the papermaking process. The papermaking black liquor is sent to the evaporator 4 through the pressure pump 9 and sprayed into the mist through the nozzle of the black liquor inlet 8. The smelting soot is from the flue gas at the bottom of the evaporator 4 The inlet 5 enters, and the black liquor is thoroughly mixed from the bottom up. The heat in the soot heats the cooker 7, completing the pulp process. At the same time, the mixed soot and black liquor react chemically, and the generated sludge and mixed gas are discharged respectively.

The mixed gas from the evaporator 7 is condensed by the condensation tower 14 to form an aqueous solution and discharged into the precipitation tank 12. In order to enhance the fluidity of the mixed gas, a duct that connects the exhaust port 3 of the evaporator 4 and the cooling tower 14 may be provided with an induced draft fan.

The clear water precipitated in the sedimentation tank is recovered and injected into the static pressure tank 15, and is used for the static pressure pulp in the papermaking process. The generated black liquor enters the black liquor tank 16 and is fed into the evaporator 4 under pressure to complete a cycle.

The resulting slag is mixed with metal oxides (smelting raw materials) in proportion, and calcined by a reflector furnace to produce carbon monoxide and carbon dioxide. The upper layer is a mixed waste slag of sodium sulfate and sodium carbonate, and the lower layer is recyclable metal lead and antimony.

The residue produced by the chemical causticizing reaction in the above steps is neutralized with sulfuric acid in the waste battery used for sodium hydroxide and calcium sulfite sedimentation.

The sediment generated in the above step is mixed with the grid and asbestos in the waste battery as the paving substrate _P. Most of the sulfuric acid (gypsum), calcium sulfite, calcium carbonate reacts with air to calcify into stones, and the residual metals are difficult to dissolve in water. , Into the atmosphere to ensure no pollution.

1. Investment in fixed assets for pollution control, including plant and equipment, has been significantly reduced. No need for bags or stainless steel equipment.

2. The present invention treats waste by waste, and the wastes are mutually utilized. The residual alkali in papermaking black liquor is the solvent for smelting lead. Organic matter in the papermaking black liquor is calcined to generate carbon monoxide, and it is a metal reducing agent for smelting including lead. At the same time, the causticizing reaction can be further used to generate an alkali that can be used as a raw material for papermaking.

3. By implementing the method of the utility model, zero emissions of papermaking and smelting industry can be realized. Industrial applicability

"The system and method for removing pollution from papermaking black liquor and smelting waste gas waste residues by using smelting waste heat papermaking are characterized in that the papermaking black liquor is sent to the evaporator and sprayed from the top of the device; the smelting flue gas enters the evaporator at the same time, On the upper spray, the sediment is generated and the mixed gas is evaporated and discharged; the mixed gas from the evaporator is condensed by the condensation tower to generate an aqueous solution and discharged into the sedimentation tank; the clear water precipitated in the sedimentation tank is recycled for the papermaking black liquor, and the produced black liquor is sent to It enters the evaporator and completes a cycle. The sodium hydroxide produced by the continuous caustic reaction is recycled for papermaking, and the generated gypsum is mixed with waste battery grids and asbestos, or it can be incinerated and digested as a paving substrate. This technology completely overcomes the current problem. There are shortcomings in technology. Through waste treatment and waste management across industries, turning waste into treasure, protecting the ecological environment, reducing production costs, investment in pollution control has been greatly reduced, and waste management has been implemented to achieve zero emissions.

Claims

A method for removing pollution from papermaking black liquor and smelting waste gas residue by using waste heat papermaking is characterized by the following process flow:

a. The papermaking black liquor is sent to the evaporator, and at the same time, the smelting flue gas enters the evaporator, and the papermaking black liquor is mixed with the smelting flue gas to generate sediment and the mixed gas is evaporated and discharged;

b. The mixed gas from the evaporator is condensed by the condensing tower to generate an aqueous solution and discharged into the precipitation tank; c. The clear water precipitated in the precipitation tank is recovered for papermaking black liquor, and the produced black liquor is sent to the evaporator to complete a cycle. 7. The method for removing contamination of papermaking black liquor and smelting waste gas by using papermaking smelting waste heat as claimed in claim 1, characterized in that the sediment and smelting raw materials generated in step a are calcined by a reflection furnace to generate carbon monoxide and carbon dioxide, and an upper layer is formed as The mixed residue of sodium sulfate and sodium carbonate, the lower layer is recyclable metals, such as lead and antimony. The method for removing pollution from papermaking black liquor and smelting waste gas waste residue by using smelting waste heat papermaking according to claim 2, characterized in that the generated mixed residue of sodium sulfate and sodium carbonate enters the causticizing reaction tank together with the clear water in the precipitation tank, and lime is added. Causticization is carried out to produce calcium sulfate (gypsum), calcium sulfite sediment, and an aqueous solution of sodium hydroxide is used for papermaking. The method for removing pollution from papermaking black liquor and smelting waste gas by using waste heat of papermaking as claimed in claim 3, characterized in that sodium hydroxide, calcium sulfite, and calcium sulfite precipitates remaining in the waste battery for causticizing reaction The sulfuric acid is neutralized and becomes neutral, and the generated neutral sediment is a building material. The method for removing papermaking black liquor and smelting waste gas pollution by using smelting waste heat papermaking according to claim 2, characterized in that said smelting raw materials are metal oxides. A system for removing contamination of papermaking black liquor and smelting waste gas residue by using waste heat of papermaking, including cooking equipment, cooling tower (14), sedimentation tank (12), static pressure tank (15), black liquor tank (16) and harsh The chemical pool (17), further comprising:

An evaporator (4), the lower part is provided with a flue gas inlet (5) and a slag discharge port (10), and the upper part is provided with a black liquid inlet (8) and an exhaust port (3);

A flue (2), the flue gas discharged from the smelting furnace (1) passes through the smelting flue (2) and enters the evaporator (4) from the flue gas inlet (5) of the evaporator (4);

The cooker (7) of the cooking equipment is located above the interior of the evaporator (4); The static pressure tank (15) described in 2004/055264 is connected to the digester (7);

The cooling tower (14) is respectively connected to the exhaust port (3) of the evaporator (4) and the precipitation tank (12). The gas from the evaporator (4) is cooled and condensed into a liquid into the precipitation in the cooling tower (14). Pool (12);

The black liquid pool (16) is respectively connected with the black liquid inlet (8) of the static pressure pool (15) and the evaporator (4). The system for removing contamination from papermaking black liquor and smelting waste gas residue by using smelting waste heat for papermaking according to claim 6, characterized in that: the duct connecting the exhaust port (3) of the evaporator (4) and the cooling tower (14) An induced draft fan is provided on it. The system for removing pollution from papermaking black liquor and smelting waste gas residues by using smelting waste heat for papermaking according to claim 6, characterized in that: an evaporator black liquor inlet (8) and a black liquor pond outlet (11) are arranged between the evaporator The pressure pump (9) is provided with a spray nozzle at the black liquid inlet (8) of the evaporator.