CN114574870B - Waste acid treatment automatic control system - Google Patents

Waste acid treatment automatic control system Download PDF

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Publication number
CN114574870B
CN114574870B CN202210168623.4A CN202210168623A CN114574870B CN 114574870 B CN114574870 B CN 114574870B CN 202210168623 A CN202210168623 A CN 202210168623A CN 114574870 B CN114574870 B CN 114574870B
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China
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gas
heat exchange
waste acid
temperature
liquid
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CN114574870A (en
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钱永清
吕学彦
曹韧
刘大欢
康兴文
朱福美
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Ningbo Bochuan Waste Liquor Treatment Co ltd
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Ningbo Bochuan Waste Liquor Treatment Co ltd
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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
    • C23G1/36—Regeneration of waste pickling liquors
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B25/00—Phosphorus; Compounds thereof
    • C01B25/16—Oxyacids of phosphorus; Salts thereof
    • C01B25/26—Phosphates
    • C01B25/37—Phosphates of heavy metals
    • C01B25/375—Phosphates of heavy metals of iron
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D133/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Coating compositions based on derivatives of such polymers
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/08—Anti-corrosive paints
    • C09D5/082—Anti-corrosive paints characterised by the anti-corrosive pigment
    • C09D5/084—Inorganic compounds
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Abstract

The invention provides an automatic control system for waste acid treatment, which comprises a waste acid storage tank and a gas-liquid mixing device, wherein a waste acid liquid is sprayed into the gas-liquid mixing device through a nozzle; the heat exchange device is provided with a low-temperature medium channel and a high-temperature medium channel; the roasting furnace is provided with a first feeding hole and a second feeding hole, the second feeding hole is connected with an outlet of the low-temperature medium channel, and solid fuel is added into the roasting furnace through the first feeding hole; the separation and dust removal device is used for treating the roasting furnace gas to form clean furnace gas and solid dust particles; the automatic control system for waste acid treatment has the advantages of simple structure, high production stability and continuity, energy conservation and environmental protection.

Description

Waste acid treatment automatic control system
Technical Field
The invention relates to the field of waste acid treatment, in particular to an automatic control system for waste acid treatment.
Background
Steel products, such as steel plates, steel pipes and the like, are important materials for production and life of people. In the production process of steel products, if the steel products are placed for a long time, a layer of iron oxide scale is formed on the surface of the steel products, the iron oxide scale needs to be washed away by acid liquor before cold rolling, and after the acid liquor is repeatedly used for a period of time, the acid concentration in the acid liquor becomes low, the impurity content in the acid liquor is increased, the iron oxide scale on the surface of the steel products cannot be effectively removed, and the acid liquor becomes waste acid liquor. Taking a small and medium-sized cold rolling plant as an example, the amount of waste acid liquid generated per day can reach dozens to hundreds of tons, and thus a large amount of waste acid liquid needs to be treated and recovered in time so as to realize the discharge and treatment of the waste acid liquid, realize the recycling of resources and reduce the production cost.
The detection result shows that: generally, the content of free hydrochloric acid in the spent acid solution generated in the cold rolling process is about 10wt%, and the content of free iron ions is about 20 to 30wt%. At present, methods for treating waste acid liquid generated by cold rolling mainly include a neutralization method, a roasting method, an evaporation method, a sulfuric acid replacement method and the like, wherein the roasting method is a method for recovering hydrochloric acid in waste acid through high-temperature roasting and simultaneously generating iron oxide red particles, and roasting modes mainly include a spray roasting method and a vulcanization roasting method.
Specifically, the spray roasting method adopts a nozzle to spray the waste acid solution into the roasting furnace from the top of the roasting furnace, simultaneously, gas is ignited to directly heat the waste acid solution in the roasting furnace for spraying, and after roasting at 500-800 ℃, hydrochloric acid in the waste acid solution is discharged out of the roasting furnace along with tail gas to form iron oxide particles at the bottom of the roasting furnace. The method has the advantages of high hydrochloric acid recovery rate, convenience and quickness, is the most widely applied method for treating the waste acid liquor at present, and accordingly, in the layout design of the acid washing machine set in China at present, the waste acid liquor is basically recovered by adopting a spray roasting method.
However, in practical use, the spray roasting method has the following defects:
firstly, the nozzle is in a high-temperature and corrosive environment for a long time, and is easy to corrode, block and scar, so that the spray roasting process is interrupted and the production cannot be stably and continuously carried out;
secondly, before roasting, the waste acid liquid is required to be introduced into a pre-concentrator to be concentrated to a set concentration and then can be sprayed into a roasting furnace for roasting, and the waste acid liquid is easy to block the throat of the pre-concentrator in the concentration process, so that the waste acid liquid treatment process is forced to be interrupted;
third, in the acid water shift process in the spray roasting method, since the hydrochloric acid concentration in both the preconcentrator and the absorption tower is low, on the one hand: iron oxide powder in the roasting furnace gas cannot fully react, and on the other hand, fine-particle iron oxide powder in the roasting furnace gas cannot be removed, so that the content of iron oxide in smoke discharged into the air exceeds the standard, and the phenomenon of red smoke is generated;
fourthly, in the roasting process, the waste acid liquid in the roasting furnace is directly heated by coal gas for spraying, so that a large amount of coal gas fuel is consumed, and environmental protection and cost reduction are not facilitated;
fifthly, in the roasting process, the waste acid liquid is directly sprayed into the roasting furnace through a nozzle, and the temperature of the waste acid liquid sprayed out from the nozzle is low, so that on one hand, the temperature of the upper part in the roasting furnace is low and unstable, and the roasting process and the discharge of roasting furnace gas are not facilitated; on the other hand, the treatment efficiency and the service life of the roasting furnace are easy to reduce;
sixthly, the impurity content of the product iron oxide particles obtained by recycling waste acid is high, and on one hand, the product iron oxide particles can be used after impurity removal treatment and are limited and troublesome in application; on the other hand, the iron-containing product obtained by the current roasting method is mainly iron oxide, so that the iron oxide produced in the market is over-supplied and over-demanded, the marketing difficulty is high, and the development of a new iron-containing product which is in line with the market demand is urgently needed.
The present application is proposed to solve the above technical problems.
Disclosure of Invention
The invention designs an automatic control system for waste acid treatment, which aims to overcome the defects that a nozzle and a preconcentrator are easy to block and damage and the continuous production stability is poor when the acid washing waste liquid is treated by the conventional roasting method; the tail gas emits red smoke; and the problems of large fuel consumption, low waste acid treatment efficiency and single product formed by waste acid treatment.
In order to solve the above problems, the present invention discloses an automatic control system for waste acid disposal, comprising:
the waste acid storage tank stores waste acid liquid generated in the pickling process;
the gas-liquid mixing device is connected with the waste acid storage tank, a nozzle is arranged in the gas-liquid mixing device, and the waste acid liquid discharged from the waste acid storage tank is sprayed into the gas-liquid mixing device in a mist shape through the nozzle;
the heat exchange device is provided with a low-temperature medium channel and a high-temperature medium channel, and the gas-liquid mixing device is connected with an inlet of the low-temperature medium channel;
the roasting furnace is provided with a first feeding hole, a second feeding hole, a furnace gas discharge hole and a slag discharge hole, the second feeding hole is connected with an outlet of the low-temperature medium channel, and solid fuel is added into the roasting furnace through the first feeding hole;
the separation and dust removal device is connected with the furnace gas discharge port, and the roasting furnace gas discharged from the furnace gas discharge port is treated by the separation and dust removal device to form clean furnace gas and solid dust particles captured by the separation and dust removal device;
the absorption device is connected with the separation and dust removal device, the separation and dust removal device is also connected with the gas-liquid mixing device, a part of clean furnace gas discharged by the separation and dust removal device enters the absorption device, and a part of gas in the clean furnace gas is absorbed by the absorption device to form recovered acid; and the other part of clean furnace gas discharged by the separation and dust removal device enters the gas-liquid mixing device, is mixed with the waste acid mist in the gas-liquid mixing device and then is discharged into the low-temperature medium channel.
Further, the waste acid disposal automatic control system further comprises:
the washing device is used for absorbing part of gas in the clean furnace gas entering the absorption device, and the rest gas enters the washing device and is discharged into the atmosphere after being washed by the washing device;
the crushing device is respectively connected with a slag discharge port in the roasting furnace and the separation and dust removal device, solid matters formed in the roasting furnace through roasting are discharged into the crushing device through the slag discharge port, and meanwhile, solid dust particles captured in the separation and dust removal device can also be discharged into the crushing device, crushed by the crushing device and uniformly mixed to form a recovery product of iron;
and the high-temperature flue gas discharge device is connected with an inlet of the high-temperature medium channel, and high-temperature flue gas discharged by the high-temperature flue gas discharge device is subjected to heat exchange with a liquid-liquid mixture discharged by the gas-liquid mixing device in the heat exchange device, and then discharged to the atmosphere after being subjected to gas washing treatment in the washing device.
Further, the gas-liquid mixing device is provided with a low-temperature waste acid liquid inlet, a medium-temperature mixture outlet and a gas return inlet, the low-temperature waste acid liquid inlet is connected with a waste acid discharge port in a waste acid storage tank, the gas return inlet is connected with the high-temperature flue gas discharge device, the medium-temperature mixture outlet is connected with an inlet of the low-temperature medium channel, the low-temperature waste acid liquid inlet, the medium-temperature mixture outlet and the gas return inlet are communicated with one another, waste acid liquid entering the gas-liquid mixing device through the low-temperature waste acid liquid inlet and high-temperature flue gas entering the gas-liquid mixing device through the gas return inlet can be mixed in the gas-liquid mixing device to form a mist gas-liquid mixture, and the mist gas-liquid mixture is discharged into the low-temperature medium channel in the heat exchange device through the medium mixture outlet.
Further, the gas-liquid mixing device includes:
the outer sleeve is a tubular structure with a hollow interior;
the inner sleeve is of a hollow tubular structure, the inner sleeve is sleeved inside the outer sleeve, and a plurality of mixing holes are formed in the side wall of the inner sleeve and are through holes;
and the side wall of the outer sleeve is provided with an air return inlet, and the two ends of the inner sleeve are opened to form the low-temperature waste acid liquid inlet and the medium-temperature mixture outlet respectively.
Further, the heat exchange device comprises: many heat exchange tubes that set up side by side, the inside space of heat exchange tube constitutes high temperature medium passageway, and the clearance between the adjacent heat exchange tube constitutes low temperature medium passageway, the heat exchange tube includes:
the heat exchange tube body is hollow inside and forms the high-temperature medium channel;
the first fin is of a sheet structure arranged on the outer side of the heat exchange tube body, and extends along the length direction of the heat exchange tube body;
the second fin is a sheet structure arranged on the outer side of the heat exchange tube body, the second fin extends along the length direction of the heat exchange tube body, and the first fin and the second fin are oppositely arranged on two sides of the heat exchange tube body by 180 degrees.
Furthermore, the first fins extend continuously along the length direction of the heat exchange tube body, and the second fins are arranged at intervals along the length direction of the heat exchange tube body.
Further, the cross section of the heat exchange tube body has a shuttle-shaped structure, and on the cross section of the heat exchange tube body, a side where the first fin is located is referred to as an upper side, a side where the second fin is located is referred to as a lower side, a straight line M is drawn through a position of the cross section of the heat exchange tube body where the horizontal width is the widest, an intersection point of the straight line M and the left tube wall is referred to as b1, an intersection point of the right tube wall is referred to as b2, an intersection point of the first fin and the heat exchange tube body is referred to as a1, an intersection point of the second fin and the heat exchange tube body is referred to as a2, a distance between the straight line M and a1 is referred to as L1, a distance between the straight line M and a2 is referred to as L2, and a distance between the points b1 and b2 is referred to as W, a value range of W is 20 to 100mm, (L1 + L2): the numeric area of W is 1.3-2, L2: the value range of L1 is 1.5-3.
Further, the roasting furnace comprises a melting cavity, a transition connection cavity and a combustion cavity which are sequentially arranged from bottom to top, wherein the cross section area of the melting cavity in the horizontal direction and the cross section area of the combustion cavity in the horizontal direction are both larger than the cross section area of the transition connection cavity in the horizontal direction.
Further, a first feeding hole is formed in the melting cavity and used for feeding solid fuel and primary air into the melting cavity;
the transition connecting cavity is provided with a second feed inlet which is used for sucking waste acid steam discharged by the heat exchange device into the transition connecting cavity;
and a third feeding port is arranged on the combustion cavity and used for feeding secondary air into the combustion cavity.
Further, the solid fuel input into the roasting furnace from the first feed inlet is a mixture of acid sludge powder and sludge powder.
The automatic control system is dealt with to spent acid have simple structure, production stability and continuity height, and energy-concerving and environment-protective advantage.
Drawings
FIG. 1 is a schematic structural diagram of an automatic control system for waste acid disposal according to the present invention;
FIG. 2 is a schematic perspective view of a gas-liquid mixing device according to the present invention at a first viewing angle;
FIG. 3 is a schematic perspective view of a gas-liquid mixing device according to the present invention at a second viewing angle;
FIG. 4 is a schematic side view of the gas-liquid mixing apparatus according to the present invention;
FIG. 5 isbase:Sub>A schematic cross-sectional view taken along the line A-A in FIG. 4;
FIG. 6 is a schematic perspective view of a heat exchange device according to the present invention;
FIG. 7 is a schematic front view of a heat exchange device according to the present invention;
FIG. 8 is a schematic top view of the heat exchange device of the present invention;
FIG. 9 is a schematic side view of the heat exchange device of the present invention;
FIG. 10 is a schematic perspective view of a heat exchange tube according to the present invention;
FIG. 11 is a schematic elevation view of a heat exchange tube according to the present invention;
FIG. 12 is a schematic top view of the heat exchange tube of the present invention;
FIG. 13 is a schematic side view of the heat exchange tube of the present invention;
fig. 14 is a schematic structural view of the roasting furnace of the present invention.
Description of reference numerals:
1. a waste acid storage tank; 101. a waste acid discharge port; 102. a waste acid discharge port; 2. a gas-liquid mixing device; 201. a low-temperature waste acid liquid inlet; 202. an outlet of the medium-temperature mixture; 203. a return air inlet; 204. an outer sleeve; 205. an inner sleeve; 206. a mixing hole; 207. an end cap; 208. a nozzle; 3. a heat exchange device; 301. a cryogenic medium channel; 302. a high temperature medium channel; 303. a tube sheet; 304. a heat exchange pipe; 304a, heat exchange tube bodies; 304b, a first fin; 304c, a second fin; 4. roasting furnace; 401. a melting chamber; 402. a transition connection cavity; 403. a combustion chamber; 404. a first feed port; 405. a second feed port; 406. a third feed inlet; 407. a furnace gas discharge port; 408. a slag discharge port; 5. a separation dust removal device; 501. a clean furnace gas discharge port; 502. a solid dust particle discharge port; 6. an absorption device; 7. a washing device; 8. a crushing device; 9. a high-temperature flue gas discharge device; 10. and a three-way valve.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
As shown in fig. 1-14, the present application provides an automatic waste acid disposal control system, comprising:
a waste acid storage tank 1 for storing waste acid liquid generated in the pickling process;
the gas-liquid mixing device 2 is connected with the waste acid storage tank 1, a nozzle 208 is arranged in the gas-liquid mixing device 2, and the waste acid liquid discharged from the waste acid storage tank 1 is sprayed into the gas-liquid mixing device 2 in a mist shape through the nozzle 208;
the heat exchange device 3 is provided with a low-temperature medium channel 301 and a high-temperature medium channel 302, and the gas-liquid mixing device 2 is connected with an inlet of the low-temperature medium channel 301;
a roasting furnace 4 having a first feed port 404, a second feed port 405, a furnace gas discharge port 407, and a slag discharge port 408, the second feed port 405 being connected to an outlet of the low-temperature medium channel 301, and solid fuel being fed into the roasting furnace 4 through the first feed port 404;
the separation and dust removal device 5 is connected with the furnace gas discharge port 407, and the roasting furnace gas discharged from the furnace gas discharge port 407 is processed by the separation and dust removal device 5 to form clean furnace gas and solid dust particles captured by the separation and dust removal device 5;
the absorption device 6 is connected with the separation and dust removal device 5, the separation and dust removal device 5 is also connected with the gas-liquid mixing device 2, a part of clean furnace gas discharged by the separation and dust removal device 5 enters the absorption device 6, and a part of gas such as HCl in the clean furnace gas is absorbed by the absorption device 6 to form recovered acid; the other part of clean furnace gas discharged by the separation and dust removal device 5 enters the gas-liquid mixing device 2, is mixed with the waste acid mist in the gas-liquid mixing device 2 and then is discharged into the low-temperature medium channel 301;
the washing device 7 is used for absorbing part of gas in the clean furnace gas entering the absorption device 6 by the absorption device 6, and the rest gas enters the washing device 7 and is discharged into the atmosphere after being washed by the washing device 7;
the crushing device 8 is respectively connected with a slag discharge port 408 in the roasting furnace 4 and the separation and dust removal device 5, solid substances formed by roasting in the roasting furnace 4 are discharged into the crushing device 8 through the slag discharge port 408, and meanwhile, solid dust particles captured in the separation and dust removal device 5 can also be discharged into the crushing device 8, crushed by the crushing device 8 and uniformly mixed to form a recovered iron product;
and the high-temperature flue gas discharge device 9 is connected with an inlet of the high-temperature medium channel 302, and high-temperature flue gas discharged by the high-temperature flue gas discharge device 9 is subjected to heat exchange with a liquid-liquid mixture discharged by the gas-liquid mixing device 2 in the heat exchange device 3, and then discharged into the washing device 7, subjected to gas washing treatment and then discharged into the atmosphere.
Further, the waste acid storage tank 1 is provided with a waste acid discharge port 101 and a waste acid discharge port 102, and a waste acid solution generated in the pickling process is discharged into the waste acid storage tank 1 through the waste acid discharge port 101 in real time, and then is discharged out of the waste acid storage tank 1 through the waste acid discharge port 102 and enters the gas-liquid mixing device 2.
Further, the gas-liquid mixing device 2 is provided with a low-temperature waste acid liquid inlet 201, a medium-temperature mixture outlet 202 and a return gas inlet 203, the low-temperature waste acid liquid inlet 201 is connected with the waste acid discharge port 102, the return gas inlet 203 is connected with the high-temperature flue gas discharge device 9, the medium-temperature mixture outlet 202 is connected with an inlet of the low-temperature medium channel 301, the low-temperature waste acid liquid inlet 201, the medium-temperature mixture outlet 202 and the return gas inlet 203 are communicated with each other, waste acid liquid entering the gas-liquid mixing device 2 through the low-temperature waste acid liquid inlet 201 and high-temperature flue gas entering the gas-liquid mixing device 2 through the return gas inlet 203 can be mixed in the gas-liquid mixing device 2 to form a mist gas-liquid mixture, and the mist gas-liquid mixture is discharged into the low-temperature medium channel 301 in the heat exchange device 3 through the medium-temperature mixture outlet 202.
Further, as shown in fig. 2 to 5, the gas-liquid mixing device 2 includes:
an outer sleeve 204, which is a tubular structure with a hollow interior;
the inner sleeve 205 is a hollow tubular structure, the inner sleeve 205 is sleeved inside the outer sleeve 204, a plurality of mixing holes 206 are formed in the side wall of the inner sleeve 205, and the mixing holes 206 are through holes;
a return air inlet 203 is arranged on the side wall of the outer sleeve 204, two ends of the inner sleeve 205 are opened to form the low-temperature spent acid liquid inlet 201 and the medium-temperature mixture outlet 202 respectively, and a part of clean furnace gas discharged by the separation and dust removal device 5 can enter the outer sleeve 204 through the return air inlet 203 and then enter the inner sleeve 205 through the mixing hole 206; after the waste acid liquid discharged from the waste acid storage tank 1 into the low-temperature waste acid liquid inlet 201 is sprayed into the inner sleeve 205 through the nozzle 208, the waste acid liquid can be mixed with clean furnace gas in the inner sleeve 205 to exchange heat to form a mist gas-liquid mixture, and the mist gas-liquid mixture is discharged through the medium-temperature mixture outlet 202.
Preferably, as shown in fig. 4, a plurality of nozzles 208 are provided at the low-temperature waste acid liquid inlet 201, and the waste acid liquid in the waste acid storage tank 1 is sprayed into the inner sleeve 205 in the form of mist through the nozzles 208.
More preferably, as shown in fig. 4, a plurality of nozzles 208 are uniformly provided in the central region of the low-temperature waste acid liquid inlet 201.
Furthermore, a plurality of mixing holes 206 are uniformly arranged on the tube side wall of the inner sleeve 205, and the number and the size of the mixing holes 206 can be changedThe opening area of the single mixing hole 206 is less than or equal to 5cm 2 To ensure the dispersion of return air, the mixing of gas and liquid and the heat exchange effect.
Further, ring-shaped end caps 207 are provided at both end portions of the outer sleeve 204, and a gap between the outer sleeve 204 and the inner sleeve 205 at both end portions is sealed by the end caps 207.
As some embodiments of the present application, the gas-liquid mixing device 2 may be used after being arranged in a horizontal direction, that is, the central axes of the outer sleeve 204 and the inner sleeve 205 are arranged in a horizontal direction; it is also possible to use the device after being arranged in the vertical direction, i.e. the central axes of the outer sleeve 204 and the inner sleeve 205 are arranged in the vertical direction.
Preferably, the gas-liquid mixing device 2 is used after being arranged in the vertical direction, the low-temperature waste acid liquid inlet 201 is located at the upper end of the gas-liquid mixing device 2, and correspondingly, the medium-temperature mixture outlet 202 is located at the lower end of the gas-liquid mixing device 2, so that waste acid mist sprayed by the spray nozzle 208 can move downwards under the action of gravity and the spray force of the spray nozzle 208, and is mixed with return air in the inner sleeve 205 to generate heat exchange, and then becomes a mist gas-liquid mixture with a higher temperature.
Further, the heat exchange device 3 is a tube type heat exchanger, the heat exchange device 3 is provided with a low-temperature medium channel 301 and a high-temperature medium channel 302, the high-temperature flue gas discharge device 9 enables high-temperature flue gas and other fluids generated in the production process of steel products to enter the high-temperature medium channel 302, and the atomized gas-liquid mixture discharged from the medium-temperature mixture outlet 202 enters the low-temperature medium channel 301 for heat exchange.
Specifically, as shown in fig. 6 to 13, the heat exchanger 3 includes:
a plurality of heat exchange tubes 304 arranged in parallel;
tube plates 303 at both ends of the heat exchange tube 304;
the space inside the heat exchange tubes 304 forms the high-temperature medium channel 302, and the gap between adjacent heat exchange tubes 304 forms the low-temperature medium channel 301, that is, the tube-side heat exchange medium of the heat exchange device 3 is the high-temperature flue gas discharged from the high-temperature flue gas discharge device 9, and the shell-side heat exchange medium of the heat exchange device 3 is the atomized gas-liquid mixture discharged from the gas-liquid mixing device 2.
In addition, the heat exchange device 2 further comprises a tube box, and a tube pass heat exchange medium inlet and outlet connecting pipe, a shell pass heat exchange medium inlet and outlet connecting pipe and the like which are arranged on the tube box. Only the structure of the heat exchange tubes 304 of the heat exchange device 22 will be described in detail, and the tube box and the heat exchange medium inlet and outlet connection tubes of the heat exchange device 2 are conventional in the prior art and will not be described in detail herein.
Further, as shown in fig. 10 to 13, the heat exchange pipe 304 includes:
the heat exchange tube body 304a is hollow inside and forms the high-temperature medium channel 302;
a first fin 304b having a plate-like structure disposed outside the heat exchange tube body 304a, the first fin 304b extending in a longitudinal direction of the heat exchange tube body 304 a;
and a second fin 304c which is a sheet-like structure and is disposed outside the heat exchange tube body 304a, wherein the second fin 304c extends along the length direction of the heat exchange tube body 304a, and the first fin 304b and the second fin 304c are disposed on two sides of the heat exchange tube body 304a in an opposite manner at an angle of 180 °.
During heat exchange, a low-temperature heat exchange medium enters the low-temperature medium channel 301 from the side where the first fin 304b is located, and leaves the low-temperature medium channel 301 from the side where the second fin 304c is located, that is, the heat exchange process between the low-temperature heat exchange medium and a single heat exchange tube 304 is as follows: first, the heat exchange tube is contacted with the first fin 304b, and in the process of contacting with the first fin 304b, the heat exchange tube exchanges heat with the first fin 304b, and meanwhile, the heat exchange tube is divided into a plurality of parts by the first fin 304b, the parts respectively enter a gap between two adjacent heat exchange tubes 304, and exchange heat with a high-temperature heat exchange medium in the heat exchange tubes 304 through the tube wall of the heat exchange tube body 304a, and then leave the heat exchange tubes 304 along the second fin 304c, and continue to exchange heat with the next heat exchange tube 304 or discharge the heat exchange device 3, and in the process of flowing through the second fin 304c, the heat exchange is simultaneously carried out with the second fin 304 c.
Further, the first fins 304b extend continuously along the length direction of the heat exchange tube body 304a, and the second fins 304c are arranged at intervals along the length direction of the heat exchange tube body 304a, so that the second fins 304c are arranged at intervals to facilitate the generation of vibration and turbulence.
Further, as shown in fig. 13, the cross section of the heat exchange tube body 304a is an axisymmetric structure, and the cross section of the heat exchange tube body 304a is a shuttle-shaped structure with a wide middle and two pointed ends.
Further, in the cross section of the heat exchange tube body 304a shown in fig. 13, when a side where the first fin 304b is located is referred to as an upper side, a side where the second fin 304c is located is referred to as a lower side, a direction parallel to the paper plane and perpendicular to the vertical direction is referred to as a horizontal direction, a straight line M is drawn through a position having the widest horizontal width in the cross section of the heat exchange tube body 304a, an intersection point of the straight line M and the left tube wall is referred to as b1, and an intersection point between the right tube wall is referred to as b2, an intersection point between the first fin 304b and the heat exchange tube body 304a is referred to as a1, an intersection point between the second fin 304c and the heat exchange tube body 304a is referred to as a2, a distance between the straight line M and the point a1 is referred to as L1, a distance between the straight line M and the point a2 is referred to as L2, and a distance between the points b1 and b2 is referred to as W, a range of W is 20 to 100mm (L1 + L2): the numeric area of W is 1.3-2, L2: the value range of L1 is 1.5-3.
Further, in the cross section of the heat exchange tube body 304a shown in fig. 13, when the height of the first fin 304b is denoted as H1 and the height of the second fin 304c is denoted as H2, the range of the H1 is 10 to 30mm, and the range of the H2 is 20 to 50mm.
This application has constituted a streamlined heat exchange tube 304 through setting gradually of the heat exchange tube body 304a of first fin 304b, fusiformis structure and second fin 304c, along the flow direction of low temperature heat transfer medium, can make fluidic flow resistance reduce by a wide margin, and heat transfer performance improves simultaneously. Specifically, the method comprises the following steps: in the heat exchange process, because the surface temperatures of the heat exchange medium and the heat exchange tube 304 are different, heat transfer can be generated, wherein a layer with the temperature continuously changing from the temperature of the heat exchange medium to the surface temperature of the heat exchange tube 304, namely a temperature boundary layer, exists on the surface of the heat exchange tube 304, the thicker the temperature boundary layer is, the larger the thermal resistance in the heat exchange process is, through the arrangement of the streamline heat exchange tube 304, when the heat exchange medium passes through gaps among the heat exchange tubes 304, on one hand, the pressure is increased, the flow velocity of fluid can be improved, on the other hand, strong turbulence can be generated, the temperature boundary layer is thinned under the combined action of the two, and the heat exchange effect is improved.
Specifically, when the fluid passes through the gaps between the heat exchange tubes 304, the process of generating turbulence is as follows: first, the low temperature heat exchange medium encounters the first fin 304b and is cut into a plurality of portions, generating tangential partial flow rates; then, the heat exchanger tube body moves along the surface of the heat exchanger tube body 304a, at this time, because the distance between two adjacent heat exchanger tube bodies 304a is smaller than the distance between two adjacent first fins 304b, a space is rapidly narrowed, pressure is rapidly increased, which will result in an increase in the flow velocity of the fluid, a thinning of a temperature boundary layer, and an improvement in the heat exchange effect; then, when the fluid continues to move, passes through the heat exchange tube body 304a, and flows to the surface of the second fin 304c, due to the obvious widening of the flow space and the sudden drop of pressure, an obvious turbulent flow is generated at the second fin 304c, and under the action of the turbulent flows at the two sides, the second fin 304c swings and generates a swing to further promote the generation of the turbulent flow, so that the temperature boundary layer is finally thinned, and the heat exchange effect is improved. In addition, the waste acid liquid and the return gas mixture in the atomized state in the low-temperature medium channel 301 are in a heterogeneous structure, and the gas and the liquid droplets are contained in the heterogeneous structure, and the gas-liquid coexisting state can disturb the flow of the fluid, so that the fluid can rapidly cross different flow layers, the generation of turbulence is further promoted, and the improvement of the heat exchange effect is promoted.
Preferably, the first fin 304b and the second fin 304c are thin sheets made of metal materials with good heat conductivity, such as copper sheets, aluminum sheets, and the like, and the arrangement of the first fin 304b and the second fin 304c can increase the heat exchange area, thereby further improving the heat exchange effect.
Generally, after passing through the heat exchange device 3, the temperature of the atomized gas-liquid mixture discharged from the gas-liquid mixing device 2 is further increased, the content of gaseous substances in the atomized gas-liquid mixture is further increased, and liquid droplets become smaller, so that the atomized gas-liquid mixture becomes a gas-liquid mixture similar to waste acid steam.
Further, as shown in fig. 14, the roasting furnace 4 includes a melting chamber 401, a transition connection chamber 402, and a combustion chamber 403, which are sequentially arranged from bottom to top, and both a horizontal cross-sectional area of the melting chamber 401 and a horizontal cross-sectional area of the combustion chamber 403 are larger than a horizontal cross-sectional area of the transition connection chamber 402. In this way, a venturi-like structure is formed by the roasting furnace 4, so that waste acid steam in the heat exchange device 3 can be automatically sucked into the roasting furnace 4.
Further, the melting chamber 401 and the combustion chamber 403 each include a lower cone section, a straight cylinder section, and an upper cone section.
Further, a first feed port 404 for feeding solid fuel and primary air into the melting chamber 401 is provided in the melting chamber 401.
Further, a third feeding port 406 is provided in the combustion chamber 403 for feeding secondary air into the combustion chamber 403.
Further, a second feed inlet 405 is disposed on the transition connection cavity 402, and is used for sucking waste acid steam discharged from the heat exchange device 3 into the transition connection cavity 402.
Furthermore, the first feed opening 404, the second feed opening 405 and/or the third feed opening 406 are tangential feed openings for feeding the respective materials tangentially into the furnace 4 and forming a rotating gas flow.
Further, a furnace gas discharge port 407 is provided at the top of the roaster 4, and a slag discharge port 408 is provided at the bottom.
In the working process of the roasting furnace 4, after heat exchange is performed by the heat exchange device 3, a gas-liquid mixture discharged from the low-temperature medium channel 301 enters a transition connection cavity 402 in the roasting furnace 4, solid fuel particles enter the melting cavity 401, the solid fuel particles are melted and liquefied in the melting cavity 401 to generate liquid slag and combustible flue gas, the combustible flue gas drives the gas-liquid mixture in the transition connection cavity 402 to move upwards under the action of combustion heat and furnace negative pressure, then the gas-liquid mixture is combusted in the combustion cavity 403, roasting furnace gas generated by combustion is discharged through furnace gas discharge ports 407 at the upper part of the roasting furnace 4, the solid furnace gas generated by combustion falls into the liquid slag in the melting cavity 401, and the solid furnace gas generated by combustion is discharged through a slag discharge port 408 at the lower part of the roasting furnace 4 after reacting with the liquid slag.
Further, the separation and dust removal device 5 is provided with a clean furnace gas discharge port 501 and a solid dust particle discharge port 502, and after the roasting furnace gas discharged from the furnace gas discharge port 407 is treated by the separation and dust removal device 5, the formed clean furnace gas and the solid dust particles captured by the separation and dust removal device 5 are discharged through the clean furnace gas discharge port 501 and the solid dust particle discharge port 502, respectively.
As some examples of the present application, the separation and dust removal device 5 may be a cyclone separator or the like.
Further, a three-way valve 10 is arranged between the separation and dust removal device 5 and the absorption device 6, an inlet of the three-way valve 110 is connected with the clean furnace gas discharge port 501, two outlets are respectively connected with the absorption device 6 and the return gas inlet 203, and the opening degrees of the two outlets in the three-way valve 10 can be continuously and automatically adjusted.
Furthermore, an absorption liquid is arranged in the absorption device 6, and after the clean furnace gas discharged from the clean furnace gas discharge port 501 is introduced into the absorption liquid, the absorption liquid can absorb gases such as HCl in the clean furnace gas, so as to form recovered acid.
As some examples of the present application, the absorption liquid is water or the like.
Furthermore, a washing liquid is arranged in the washing device 7, and the washing liquid is Na 2 CO 3 And the like.
Further, the crushing device 8 is connected to a slag discharge port 408 in the roaster 4 and a solid dust particle discharge port 502 in the dust separation and removal device 5, respectively, solid matters formed by roasting in the roaster 4 are discharged into the crushing device 8 through the slag discharge port 407, and meanwhile, solid dust particles captured in the dust separation and removal device 5 can also be discharged into the crushing device 8.
Preferably, a granulating device is provided between the slag discharge port 408 and the crushing device 8 so that the slag discharged from the slag discharge port 408 is granulated.
Further, the slag powder discharged from the crushing apparatus 8 can be used as a rust preventive in a rust preventive pigment or a corrosion preventive paint.
Preferably, when the solid powder discharged from the crushing apparatus 8 is used as a rust preventive in an anticorrosive paint, the anticorrosive paint includes: 60-80 parts of acrylic emulsion, 20-30 parts of purified water, 10-25 parts of epoxy resin, 5-20 parts of wollastonite, 3-5 parts of phosphoric acid, 0.5-3 parts of antirust agent and 0.5-1 part of dispersing agent; the preparation process of the anticorrosive coating comprises the following steps: adding purified water, wollastonite, phosphoric acid, an antirust agent and a dispersing agent into a grinding machine, grinding until the average particle size is 30-100 um, adding acrylic emulsion and epoxy resin, stirring uniformly, and adjusting the pH value to 7-9 to obtain the anticorrosive paint.
Furthermore, an automatic control valve is arranged on each feeding and discharging port, such as the waste acid discharging port 101, the waste acid discharging port 102, and the like, and the opening and closing of the corresponding feeding and discharging port are controlled through the opening and closing of the automatic control valve.
In addition, this application still provides a spent acid processing method, and the aforesaid spent acid is dealt with automatic control system and is dealt with according to the following method and carry out the spent acid, the method includes the step:
s1, opening a first feeding hole 404 to input solid fuel and primary air into a roasting furnace 4, and simultaneously opening a third feeding hole 406 to input secondary air into the roasting furnace 4;
s2, after the solid fuel is melted and liquefied in the roasting furnace 4, liquid slag and combustible flue gas are generated, the combustible flue gas moves upwards under the action of primary air and negative pressure in the furnace, then the combustible flue gas is combusted in a combustion cavity 403, furnace gas generated by combustion is discharged through a furnace gas discharge port 407 in the upper part of the roasting furnace 4, solid particles generated by combustion fall into the liquid slag in the melting cavity 401, and the solid particles are discharged through a furnace slag discharge port 408 in the lower part of the roasting furnace 4 after reacting with the liquid slag;
s3, monitoring furnace gas discharged from the roasting furnace 4, opening the three-way valve 10 when the temperature of the furnace gas discharged from the furnace gas discharge port 407 reaches 300 ℃, introducing part of the furnace gas discharged from the furnace gas discharge port 407 into the air return inlet 203 of the gas-liquid mixing device 2, and introducing the rest of the furnace gas into the absorption device 6; meanwhile, a waste acid outlet 102 of the waste acid storage tank 1 is opened, waste acid mist formed by waste acid liquid is sprayed into an inner sleeve 205 of the gas-liquid mixing device 2, furnace gas introduced through a gas return inlet 203 enters the inner sleeve 205 through a mixing hole 206, is mixed with the waste acid mist in the inner sleeve 205, exchanges heat and then is discharged into a low-temperature medium channel 301 in the heat exchange device 3; before the temperature of furnace gas discharged from a furnace gas discharge port 407 reaches 300 ℃, the furnace gas can be directly discharged into a washing device 7, and is discharged to the atmosphere after being treated by the washing device 7 and reaching the discharge standard;
s4, opening the high-temperature flue gas discharge device 9 to introduce high-temperature flue gas into the high-temperature medium channel 302 in the heat exchange device 3, and allowing a gas-liquid mixture in the low-temperature medium channel 301 to exchange heat with the high-temperature flue gas in the high-temperature medium channel 302 and then enter the roasting furnace 4 through the second feed port 405;
s5, after the solid fuel is melted and liquefied in the roasting furnace 4, liquid slag and combustible flue gas are generated, the combustible flue gas drives the gas-liquid mixture fed by the second feeding hole 405 to move upwards under the action of primary air and negative pressure in the furnace, then the combustible flue gas is combusted in the combustion cavity 403, furnace gas generated by combustion is discharged through a furnace gas discharge port 407 at the upper part of the roasting furnace 4, solid particles generated by combustion fall into the liquid slag in the melting cavity 401, and the solid particles are reacted with the liquid slag and then discharged through a furnace slag discharge port 408 at the lower part of the roasting furnace 4;
s6, the furnace gas discharged from the furnace gas discharge port 407 enters a separation and dust removal device 5, and the clean furnace gas formed after being processed by the separation and dust removal device 5 and the solid dust particles captured by the separation and dust removal device 5 are discharged through the clean furnace gas discharge port 501 and the solid dust particle discharge port 502 respectively;
s6, introducing part of clean furnace gas discharged from the clean furnace gas discharge port 501 into a gas return inlet 203 in the gas-liquid mixing device 2, introducing the rest furnace gas into an absorption device 6, and forming recovered acid after HCl and other gases in the clean furnace gas are absorbed by the absorption device 6;
s7, introducing the gas which is not absorbed by the absorption device 6 in the clean furnace gas into a washing device 7, treating the gas by the washing device 7 to reach the emission standard, and then discharging the gas to the atmosphere.
Further, in the step S5, the temperature in the combustion chamber 403 is about 500 to 800 ℃, and the temperature in the melting chamber 401 is about 400 to 600 ℃.
Further, the temperature of the flue gas discharged by the high-temperature flue gas discharge device 9 is more than or equal to 300 ℃, preferably, the temperature of the flue gas discharged by the high-temperature flue gas discharge device 9 is 300-500 ℃.
As some embodiments of the present application, the high temperature flue gas discharge device 9 may be a device that generates high temperature flue gas in the production process of steel products, and may also be other devices that can discharge high temperature flue gas.
Preferably, in the production process of the steel product, the cold rolling and annealing processes are usually matched to eliminate the residual stress generated in the cold rolling process through annealing, so that the high-temperature flue gas discharge device 9 selects annealing equipment such as a belt type continuous annealing furnace and the like, and discharges the generated high-temperature flue gas into the high-temperature medium channel 302 in the heat exchange device 3 for heat exchange.
Further, the solid fuel input into the roasting furnace 4 from the first input port 404 is a mixture of acid sludge powder and sludge powder.
Preferably, the acid sludge powder is obtained by filtering the waste acid solution to obtain a solid, and then drying and crushing the solid to obtain the acid sludge powder with the average particle size of less than or equal to 1mm and the water content of less than 10 wt%.
More preferably, before the waste acid liquid is sent to the gas-liquid mixing device 2 or the waste acid storage tank 1, the waste acid liquid is filtered, dried and crushed to obtain acid sludge powder.
Preferably, the sludge powder is a crushed solid waste, and more preferably, the sludge powder is dried sludge with a water content of less than 10 wt%.
Furthermore, the weight ratio of the acid sludge to the sludge in the solid fuel is 1:5-1.
Further, in the waste acid disposal method, the amount of the solid fuel input from the first input port 404 is determined according to the calorific value of the solid fuel used and the amount of the waste acid steam input from the second input port 405, and generally, 1 to 3Kg of the solid fuel with the calorific value of 10 to 15KJ/Kg is consumed for every 1L of the waste acid steam; the first inlet 404 preferably feeds the primary air in an amount to achieve an oxygen content of 0.8 to 1 in the melting chamber 401, and the third inlet 406 preferably feeds the secondary air in an amount to achieve an oxygen content of 1.1 to 1.3 in the combustion chamber 403.
Further, generally, after the operation is performed for 10 to 30 minutes, the automatic waste acid disposal control system can reach a stable operation state, and in the stable operation state, when the temperature of the high-temperature flue gas discharged by the high-temperature flue gas discharge device 9 is 300 to 500 ℃ and the temperature of the furnace gas discharged by the roasting furnace 4 is 300 to 500 ℃, after passing through the separation and dust removal device 5, the temperature of the clean furnace gas flowing back to the gas return port 203 is about 200 to 400 ℃, and when the temperature of the waste acid liquid discharged by the waste acid storage tank 1 is about room temperature to 55 ℃, the waste acid liquid is mixed with the clean furnace gas in the gas-liquid mixing device 2, exchanges heat, forms waste acid mist with the temperature of about 80 to 95 ℃, then forms waste acid steam with the temperature of about 100 to 150 ℃ after exchanging heat with the high-temperature flue gas in the heat exchange device 3, and then is sucked into the roasting furnace 4 to be combusted in the combustion chamber 403.
Further, the opening of the three-way valve 10 is adjusted according to the amount of the waste acid solution entering the gas-liquid mixing device 2, so that waste acid mist with a temperature of about 80 to 95 ℃ can be formed after mixing and heat exchange by the gas-liquid mixing device 2.
Further, the opening degree of the waste acid discharge port 102 is adjusted according to the amount and temperature of the high-temperature flue gas discharged by the high-temperature flue gas discharge device 9, so that waste acid steam with the temperature of about 100-150 ℃ can be formed after heat exchange by the heat exchange device 3.
In addition, the red smoke phenomenon is not generated in the process of carrying out the waste acid liquid recovery treatment according to the waste acid treatment method.
Specifically, the chemical reaction performed in the roasting furnace 4 mainly includes the following types:
under the action of high temperature in the roasting furnace 4, organic matters in the solid fuel are rapidly combusted and decomposed to form CO 2 、H 2 Discharging O, etc., and removing the rest non-combustible components such as SiO 2 、CaO、P 2 O 5 Melting the components such as trace heavy metals and the like and then remaining in the liquid slag;
heating volatile gases such as HCl in the waste acid liquid to volatilize;
FeCl in waste acid liquid 2 The particles are roasted into free hydrogen chloride and ferric oxide when falling in the furnace, and then fall into liquid slag to be melted;
the iron oxide melted into the liquid slag undergoes a complex chemical reaction with the components in the liquid slag, and a mixture containing iron phosphate, calcium hydrogen phosphate, calcium dihydrogen phosphate, calcium carbonate, iron silicate and the like is finally generated.
In conclusion, it is easy to find that the automatic control system for waste acid disposal described in the present application has the following advantages:
firstly, the nozzle 208 is moved forward and arranged at the low-temperature waste acid liquid inlet 201 of the gas-liquid mixing device 2, so that the nozzle 208 is in a relatively low-temperature environment, and on one hand, the corrosion is slowed down due to the reduction of the temperature; on the other hand, the waste acid liquid is not easy to react in a low-temperature environment, block the nozzle 208 or generate scab on the nozzle 208, and finally the service life of the nozzle 208 can be greatly prolonged;
secondly, the method of returning part of the clean furnace gas to the gas-liquid mixing device 2 is adopted, so that the content of HCl in the fluid entering the heat exchange device 3 and the fluid entering the roasting furnace 4 can be rapidly increased, the pre-treatment by using a pre-concentrator is avoided, and the problem of production interruption caused by blockage of the pre-concentrator is solved; meanwhile, as the content of HCl in the fluid entering the roasting furnace 4 is increased, the phenomenon of red smoke caused by insufficient reaction and removal of ferric oxide powder is avoided;
thirdly, the mixture of the sludge and the waste acid sludge is adopted to replace a gas dye, so that the waste acid liquid is roasted while the sludge and the waste acid sludge are incinerated, the environment is protected, and the cost can be reduced;
fourthly, the gas-liquid mixing device 2 and the heat exchange device 3 are adopted to pretreat the waste acid liquid, the waste acid liquid introduced into the roasting furnace 4 is waste acid steam with the temperature of 100-150 ℃, on one hand, the high-temperature waste acid steam can quickly and completely react with combustible flue gas to complete the roasting process, so that the overall treatment efficiency of the waste acid liquid is improved, on the other hand, the furnace temperature is stably controlled, the stable continuity of production is improved, and the service life of the roasting furnace is prolonged;
fifth, in recent years, due to rapid development of the battery industry, the consumption of lithium iron phosphate is too high, and further, iron phosphate gaps are too large and the price of iron phosphate is increased, so that the price of an antirust pigment and an antirust agent which take iron phosphate as a main active ingredient is increased.
The above waste acid disposal method is illustrated by the following specific examples:
example 1
S1, opening a first feeding hole 404 to input solid fuel and primary air into a roasting furnace 4, and simultaneously opening a third feeding hole 406 to input secondary air into the roasting furnace 4, wherein the heat value of the solid fuel is 10MJ/Kg, the input speed is 3Kg/min, the peroxide coefficient in a melting cavity 401 is 0.8, and the peroxide coefficient in a combustion chamber 403 is 1.2;
s2, after the solid fuel is melted and liquefied in the roasting furnace 4, liquid slag and combustible flue gas are generated, the pressure in the furnace is-0.01 MPa, the combustible flue gas moves upwards under the action of primary air and negative pressure in the furnace, the movement speed is about 0.4m/S, then the combustible flue gas is combusted in a combustion cavity 403, furnace gas generated by combustion is discharged through a furnace gas discharge port 407 at the upper part of the roasting furnace 4, solid particles generated by combustion fall into the liquid slag in the melting cavity 401, and the solid particles are discharged through a furnace slag discharge port 408 at the lower part of the roasting furnace 4 after reacting with the liquid slag;
s3, monitoring the furnace gas discharged from the roasting furnace 4, and after 22min, when the temperature of the furnace gas discharged from the furnace gas discharge port 407 reaches 306 ℃, opening the three-way valve 10, introducing 80% of the furnace gas discharged from the clean furnace gas discharge port 501 into the return air inlet 203 of the gas-liquid mixing device 2, and introducing the rest furnace gas into the absorption device 6; simultaneously, a waste acid outlet 102 of the waste acid storage tank 1 is opened, waste acid mist formed by waste acid liquid is sprayed into an inner sleeve 205 of the gas-liquid mixing device 2, the speed of the waste acid liquid discharged from the waste acid outlet 102 is 2L/min, furnace gas introduced through a gas return inlet 203 enters the inner sleeve 205 through a mixing hole 206, is mixed with the waste acid mist in the inner sleeve 205, forms waste acid mist with the temperature of about 85 ℃ after heat exchange, and is discharged into a low-temperature medium channel 301 in the heat exchange device 3;
s4, opening the high-temperature flue gas discharge device 9 to introduce high-temperature flue gas into the high-temperature medium channel 302 in the heat exchange device 3, wherein the temperature of the high-temperature flue gas in the high-temperature medium channel 302 is 450 ℃, and the flow rate of the high-temperature flue gas is 0.7m 3 The fluid in the low-temperature medium channel 301 exchanges heat with the high-temperature flue gas in the high-temperature medium channel 302 to form waste acid steam, the temperature of the waste acid steam is about 120 ℃, and then the waste acid steam enters the roasting furnace 4 through the second feed port 405;
s5, the solid fuel is melted and liquefied in the roasting furnace 4 to generate liquid slag and combustible flue gas, the temperature in the melting cavity 401 is about 450-480 ℃, and the peroxide coefficient is 0.8; the combustible flue gas drives the waste acid liquid steam fed by the second feeding hole 405 to move upwards under the action of primary air and negative pressure in the furnace, then the waste acid liquid steam is combusted in the combustion cavity 403, the temperature in the combustion cavity 403 is about 600-650 ℃, the peroxide coefficient is 1.3, furnace gas generated by combustion is discharged through a furnace gas discharge port 407 at the upper part of the roasting furnace 4, solid particles generated by combustion fall into liquid slag in the melting cavity 401, and the solid particles are reacted with the liquid slag and then discharged through a furnace slag discharge port 408 at the lower part of the roasting furnace 4;
s6, furnace gas discharged from the furnace gas discharge port 407 enters the separation and dust removal device 5, and clean furnace gas formed after treatment by the separation and dust removal device 5 and solid dust particles captured by the separation and dust removal device 5 are discharged through the clean furnace gas discharge port 501 and the solid dust particle discharge port 502 respectively;
s6, after the operation is carried out for 1.5 hours, 40% of clean furnace gas discharged from the clean furnace gas discharge port 501 is adjusted to be introduced into the gas return inlet 203 of the gas-liquid mixing device 2 by the separation and dust removal device 5, the rest furnace gas is introduced into the absorption device 6, HCl and other gases in the clean furnace gas are absorbed by the absorption device 6 to form recovered acid, and the mass percentage concentration of HCl in the recovered acid is 26%;
s7, introducing the gas which is not absorbed by the absorption device 6 in the clean furnace gas into a washing device 7, treating the gas by the washing device 7 to reach the emission standard, and then discharging the gas to the atmosphere.
Example 2
S1, opening a first feeding hole 404 to input solid fuel and primary air into a roasting furnace 4, and simultaneously opening a third feeding hole 406 to input secondary air into the roasting furnace 4, wherein the heat value of the solid fuel is 14MJ/Kg, the input speed is 3Kg/min, the peroxide coefficient in a melting cavity 401 is 0.9, and the peroxide coefficient in a combustion chamber 403 is 1.1;
s2, after the solid fuel is melted and liquefied in the roasting furnace 4, liquid slag and combustible flue gas are generated, the pressure in the furnace is-0.03 MPa, the combustible flue gas moves upwards under the action of primary air and negative pressure in the furnace, the movement speed is about 0.5m/S, then the combustible flue gas is combusted in a combustion cavity 403, furnace gas generated by combustion is discharged through a furnace gas discharge port 407 at the upper part of the roasting furnace 4, solid particles generated by combustion fall into the liquid slag in the melting cavity 401, and the solid particles are discharged through a furnace slag discharge port 408 at the lower part of the roasting furnace 4 after reacting with the liquid slag;
s3, monitoring the furnace gas discharged from the roasting furnace 4, and after 16min, when the temperature of the furnace gas discharged from the furnace gas discharge port 407 reaches 304 ℃, opening the three-way valve 10, introducing 80% of the furnace gas discharged from the clean furnace gas discharge port 501 into the return air inlet 203 of the gas-liquid mixing device 2, and introducing the rest furnace gas into the absorption device 6; simultaneously, a waste acid outlet 102 of a waste acid storage tank 1 is opened, waste acid mist formed by waste acid liquid is sprayed into an inner sleeve 205 of the gas-liquid mixing device 2, the speed of the waste acid liquid discharged from the waste acid outlet 102 is 1L/min, furnace gas introduced through a gas return inlet 203 enters the inner sleeve 205 through a mixing hole 206, is mixed with the waste acid mist in the inner sleeve 205, forms waste acid mist with the temperature of about 93 ℃ after heat exchange, and is discharged into a low-temperature medium channel 301 in a heat exchange device 3;
s4, opening the high-temperature flue gas discharge device 9 to introduce high-temperature flue gas into the high-temperature medium channel 302 in the heat exchange device 3, wherein the temperature of the high-temperature flue gas in the high-temperature medium channel 302 is 460 ℃, and the flow rate is 0.65m 3 The fluid in the low-temperature medium channel 301 exchanges heat with the high-temperature flue gas in the high-temperature medium channel 302 to form waste acid steam, the temperature of the waste acid steam is about 128 ℃, and then the waste acid steam enters the roasting furnace 4 through the second feeding hole 405;
s5, after the solid fuel is melted and liquefied in the roasting furnace 4, liquid slag and combustible flue gas are generated, the temperature in the melting cavity 401 is about 450-480 ℃, and the peroxide coefficient is 0.8; the combustible flue gas drives the waste acid liquid steam fed by the second feed port 405 to move upwards together under the action of primary air and negative pressure in the furnace, then the waste acid liquid steam is combusted in the combustion chamber 403, the temperature in the combustion chamber 403 is about 600-650 ℃, the peroxide coefficient is 1.3, furnace gas generated by combustion is discharged through a furnace gas discharge port 407 at the upper part of the roasting furnace 4, solid particles generated by combustion fall into liquid slag in the melting chamber 401, and the solid particles are discharged through a furnace slag discharge port 408 at the lower part of the roasting furnace 4 after reacting with the liquid slag;
s6, the furnace gas discharged from the furnace gas discharge port 407 enters a separation and dust removal device 5, and the clean furnace gas formed after being processed by the separation and dust removal device 5 and the solid dust particles captured by the separation and dust removal device 5 are discharged through the clean furnace gas discharge port 501 and the solid dust particle discharge port 502 respectively;
s6, after the operation is carried out for 1h, adjusting the separation and dust removal device 5 to ensure that 40% of clean furnace gas discharged from the clean furnace gas discharge port 501 is introduced into the gas return inlet 203 of the gas-liquid mixing device 2, introducing the rest furnace gas into the absorption device 6, and forming recovered acid after HCl and other gases in the clean furnace gas are absorbed by the absorption device 6, wherein the mass percentage concentration of HCl in the recovered acid is 28%;
s7, introducing the gas which is not absorbed by the absorption device 6 in the clean furnace gas into a washing device 7, treating the gas by the washing device 7 to reach the emission standard, and then discharging the gas to the atmosphere.
Example 3
An anticorrosive paint was prepared by using, as rust inhibitors, slag powders obtained by the treatment of the crushing apparatus 8 in the above examples 1 and 2, respectively, and the anticorrosive paint included: 65 parts of acrylic emulsion, 20 parts of purified water, 12 parts of epoxy resin, 10 parts of wollastonite, 3 parts of phosphoric acid, 1 part of antirust agent and 0.5 part of dispersing agent.
The preparation process of the anticorrosive paint is as follows: adding purified water, wollastonite, phosphoric acid, an antirust agent and a dispersing agent into a grinding machine, grinding until the average particle size is 50-60 um, adding acrylic emulsion and epoxy resin, stirring uniformly, and adjusting the pH value to 9 to obtain the anticorrosive paint.
Comparative example 1
The comparative example differs from example 3 only in that analytically pure iron phosphate was used as the rust inhibitor, and the remaining components and the anticorrosive paint were prepared in the same manner.
Test example 1
The anticorrosive coatings prepared in the above example 3 and comparative example 1 are uniformly coated on a steel plate, and after the coatings are completely dried, a salt spray test is performed according to GB/T1771-2007 standard, and the test results are as follows:
test time (h) Example 3 Comparative example 1
24 The coating is intact and unchanged The coating is intact and unchanged
48 The coating is intact and unchanged The coating is intact and unchanged
72 The coating is intact and unchanged Has a spot-like precipitate and no rust
96 Has a spot-like precipitate and no rust Little falling off and no rust
Although the present invention is disclosed above, the present invention is not limited thereto. In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (8)

1. An automatic control system for spent acid disposal, comprising:
the waste acid storage tank (1) stores waste acid liquid generated in the pickling process;
the gas-liquid mixing device (2) is connected with the waste acid storage tank (1), a nozzle (208) is arranged in the gas-liquid mixing device (2), and the waste acid liquid discharged from the waste acid storage tank (1) is sprayed into the gas-liquid mixing device (2) in a mist shape through the nozzle (208);
the heat exchange device (3) is provided with a low-temperature medium channel (301) and a high-temperature medium channel (302), and the gas-liquid mixing device (2) is connected with an inlet of the low-temperature medium channel (301);
a roasting furnace (4) having a first feed opening (404), a second feed opening (405), a furnace gas discharge opening (407) and a slag discharge opening (408), the second feed opening (405) being connected to an outlet of the cryogenic medium channel (301), solid fuel being introduced into the roasting furnace (4) through the first feed opening (404);
the separation and dust removal device (5) is connected with the furnace gas discharge port (407), and the roasting furnace gas discharged from the furnace gas discharge port (407) is treated by the separation and dust removal device (5) to form clean furnace gas and solid dust particles captured by the separation and dust removal device (5);
the absorption device (6) is connected with the separation and dust removal device (5), the separation and dust removal device (5) is also connected with the gas-liquid mixing device (2), a part of clean furnace gas discharged by the separation and dust removal device (5) enters the absorption device (6), and a part of gas in the clean furnace gas is absorbed by the absorption device (6) to form recovered acid; the other part of clean furnace gas discharged by the separation and dust removal device (5) enters the gas-liquid mixing device (2), is mixed with the waste acid mist in the gas-liquid mixing device (2) and then is discharged into the low-temperature medium channel (301);
the washing device (7) is used for absorbing part of gas in the clean furnace gas entering the absorption device (6) by the absorption device (6), and the rest gas enters the washing device (7), is washed by the washing device (7) and is discharged to the atmosphere;
the high-temperature flue gas discharging device (9) is connected with an inlet of the high-temperature medium channel (302), and high-temperature flue gas discharged by the high-temperature flue gas discharging device (9) is subjected to heat exchange with a liquid-liquid mixture discharged by the gas-liquid mixing device (2) in the heat exchange device (3), discharged into the washing device (7), subjected to gas washing treatment and discharged into the atmosphere;
the gas-liquid mixing device (2) is provided with a low-temperature waste acid liquid inlet (201), a medium-temperature mixture outlet (202) and a return gas inlet (203), the low-temperature waste acid liquid inlet (201) is connected with a waste acid discharge port (102) in a waste acid storage tank (1), the return gas inlet (203) is connected with a clean furnace gas discharge port (501) in the separation and dust removal device (5), the medium-temperature mixture outlet (202) is connected with an inlet of the low-temperature medium channel (301), the low-temperature waste acid liquid inlet (201), the medium-temperature mixture outlet (202) and the return gas inlet (203) are communicated with each other, waste acid liquid entering the gas-liquid mixing device (2) through the low-temperature waste acid liquid inlet (201) and high-temperature flue gas entering the gas-liquid mixing device (2) through the return gas inlet (203) can be mixed in the gas-liquid mixing device (2) to form a mist gas-liquid mixture, and the gas-liquid mixture can be discharged into the low-temperature medium channel (301) in the heat exchange device (3) through the medium mixture outlet (202);
the gas-liquid mixing device (2) comprises:
an outer sleeve (204) which is a tubular structure with a hollow interior;
the inner sleeve (205) is of a hollow tubular structure, the inner sleeve (205) is sleeved inside the outer sleeve (204), the side wall of the inner sleeve (205) is provided with a plurality of mixing holes (206), and the mixing holes (206) are through holes;
and a return air inlet (203) is arranged on the side wall of the outer sleeve (204), and two ends of the inner sleeve (205) are opened to form the low-temperature waste acid liquid inlet (201) and the medium-temperature mixture outlet (202) respectively.
2. The spent acid treatment automatic control system of claim 1, further comprising:
crushing device (8), crushing device (8) respectively with slag discharge port (408) in the burning furnace (4) and separation dust collector (5) are connected, the solid matter that forms through the calcination in the burning furnace (4) passes through slag discharge port (408) arrange extremely in crushing device (8), simultaneously, the solid dust granule that catches in separation dust collector (5) also can arrange extremely in crushing device (8), warp form the recovery product of iron after crushing device (8) is broken and the mixing.
3. An automatic control system for waste acid disposal according to claim 1, wherein said heat exchange means (3) comprises: a plurality of heat exchange tubes (304) arranged in parallel, the space inside the heat exchange tubes (304) constitutes the high temperature medium channel (302), the gap between adjacent heat exchange tubes (304) constitutes the low temperature medium channel (301), the heat exchange tubes (304) include:
the heat exchange tube body (304 a) is hollow inside and forms the high-temperature medium channel (302);
a first fin (304 b) which is a sheet-like structure provided outside the heat exchange tube body (304 a), the first fin (304 b) extending in a longitudinal direction of the heat exchange tube body (304 a);
and a second fin (304 c) which is a sheet-like structure and is arranged outside the heat exchange tube body (304 a), wherein the second fin (304 c) extends along the length direction of the heat exchange tube body (304 a), and the first fin (304 b) and the second fin (304 c) are oppositely arranged on two sides of the heat exchange tube body (304 a) in an angle of 180 degrees.
4. An automatic control system of waste acid disposal as recited in claim 3, wherein said first fins (304 b) extend continuously along a length of said heat exchange tube body (304 a), and said second fins (304 c) are spaced along a length of said heat exchange tube body (304 a).
5. The automatic control system for waste acid disposal according to claim 3 or 4, wherein the cross section of the heat exchange tube body (304 a) is in a shuttle-shaped structure, the side where the first fin (304 b) is located is referred to as upper side, the side where the second fin (304 c) is located is referred to as lower side, a straight line M is drawn through the widest horizontal position in the cross section of the heat exchange tube body (304 a), the intersection point of the straight line M and the left tube wall is referred to as b1, the intersection point of the right tube wall is referred to as b2, the intersection point of the first fin (304 b) and the heat exchange tube body (304 a) is referred to as a1, the intersection point of the second fin (304 c) and the heat exchange tube body (304 a) is referred to as a2, the distance between the straight line M and the point a1 is referred to as L1, the distance between the straight line M and the point a2 is referred to as L2, and the distance between the points b1 and b2 is referred to as W, and the range of values of (20-L + 1002) is defined as: the value range of W is 1.3 to 2, L2: the value range of L1 is 1.5 to 3.
6. An automatic control system for waste acid disposal according to claim 1, wherein said roasting furnace (4) comprises a melting chamber (401), a transitional connection chamber (402) and a combustion chamber (403) arranged in sequence from bottom to top, and both the cross-sectional area of said melting chamber (401) in the horizontal direction and the cross-sectional area of said combustion chamber (403) in the horizontal direction are larger than the cross-sectional area of said transitional connection chamber (402) in the horizontal direction.
7. The spent acid treatment automatic control system of claim 6,
a first feeding hole (404) is formed in the melting cavity (401) and used for feeding solid fuel and primary air into the melting cavity (401);
a second feeding hole (405) is formed in the transitional connection cavity (402) and is used for sucking waste acid steam discharged by the heat exchange device (3) into the transitional connection cavity (402);
the combustion chamber (403) is provided with a third feed opening (406) for feeding secondary air into the combustion chamber (403).
8. An automatic control system for waste acid disposal according to claim 1 or 7, wherein the solid fuel fed into the roasting furnace (4) through the first feed inlet (404) is a mixture of acid sludge powder and sludge powder.
CN202210168623.4A 2022-02-23 2022-02-23 Waste acid treatment automatic control system Active CN114574870B (en)

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