A device and process for zero-emission resource disposal of pickling process waste

Abstract

The present invention relates to a zero-emission resource disposal device for wastes from a pickling process, wherein the acid sludge outlet of the pickling unit is connected to a sludge evaporator, a grinder and a solid-liquid mixer in sequence; the waste rinsing water outlet of the pickling unit is connected to a rinsing water concentrator and a solid-liquid mixer in sequence; the waste acid outlet and the solid-liquid mixer of the pickling unit are both connected to a roasting reactor; the tail gas outlet of the pickling unit and the roasting reactor are both connected to an acid absorber, and the acid absorber is connected to a denitrification reactor and a sludge evaporator in sequence; and the disposal process thereof is as follows: the acid sludge discharged from the pickling unit is dried and ground, mixed with the concentrated rinsing water after the waste rinsing water discharged from the pickling unit is concentrated, and is supplied to the roasting reactor together with the waste acid discharged from the pickling unit for reaction, and the generated acid regeneration tail gas and the tail gas discharged from the pickling unit are subjected to acid absorption and denitrification, and then heat exchanged with the acid sludge. The present invention completely recycles the acidic solid waste, waste liquid and waste gas generated by the pickling unit to achieve zero emission, and also utilizes waste heat to reduce energy consumption.

Description

Technical Field

[0001] The present invention relates to the technical field of resource disposal and recycling of pickling waste, and in particular to a zero-emission resource disposal device and process for pickling process waste. Background Art

[0002] In the pickling process of the metallurgical industry, a large amount of acid is used to pickle plates, rods and wires, etc., which produces a large amount of acid waste gas and pickling waste liquid, as well as a large amount of acid sludge solid waste composed of iron oxide scale on the surface of the substrate and settled metal acid compounds. These pickling waste liquids and acid sludge contain waste acid and heavy metals, which are the most serious pollutants in metallurgical enterprises and are listed in the list of hazardous wastes.

[0003] For pickling waste liquid and sludge solid waste, steel enterprises usually use lime to neutralize them to form neutralized sludge sediments. The treatment cost is very high and a larger amount of heavy metal sludge is produced, which has a greater impact on the environment and greatly wastes resources. For pickling waste gas, an acid mist purification tower is usually set up to absorb it, and then the absorption liquid is combined with other pickling waste liquids before being neutralized with lime.

[0004] Some companies also use filter presses to filter pickling sludge solid waste into mud cakes, and then transport them to metallurgical smelting systems as raw materials and mixed with iron ore as a treatment method. However, since acid sludge contains a large amount of acidic components, it will cause serious corrosion to smelting equipment, often resulting in equipment damage and affecting production.

[0005] Especially in the production and preparation of stainless steel, nitric acid is often used as the pickling raw material, which produces highly corrosive nitric acid-containing waste liquid and NO-containing waste liquid. x If the exhaust gas is not properly treated, it will cause serious pollution to the environment. The denitrification reactor set up to meet the emission standards needs to use a heat source to meet the temperature requirements of tail gas denitrification. In addition, the denitrification reaction is exothermic. If the tail gas is discharged directly, this part of the heat will be directly lost. Summary of the invention

[0006] In order to overcome the deficiencies of the above-mentioned prior art, the purpose of the present invention is to provide a zero-emission resource disposal device and process for pickling process waste, which can completely recycle the acidic solid waste, waste liquid and waste gas generated by the pickling unit to achieve zero emission.

[0007] To achieve the above-mentioned purpose, the technical solution of the present invention is a zero-emission resource disposal device for pickling process waste, comprising a pickling unit, a sludge evaporator, a grinder, a rinse water concentrator, a solid-liquid mixer, a roasting reactor, an acid absorber and a denitrification reactor; the acid sludge outlet of the pickling unit is connected to the sludge evaporator, the grinder and the solid-liquid mixer in sequence through a material pipeline; the waste rinse water outlet of the pickling unit is connected to the rinse water concentrator, and the concentrated rinse water outlet of the rinse water concentrator is connected to the solid-liquid mixer; the waste acid outlet of the pickling unit and the material outlet of the solid-liquid mixer are both connected to the material inlet of the roasting reactor; the exhaust gas outlet of the pickling unit and the exhaust gas outlet of the roasting reactor are both connected to the acid absorber, and the exhaust gas outlet of the acid absorber is connected to the denitrification reactor and the sludge evaporator in sequence through a gas pipeline.

[0008] Furthermore, the sludge evaporation tail gas outlet of the sludge evaporator is connected to the acid absorber through a gas pipeline.

[0009] Furthermore, the regeneration acid outlet of the acid absorber is connected to the pickling unit.

[0010] Furthermore, the regenerated rinse water outlet of the rinse water concentrator is connected to the pickling unit.

[0011] Further, the regenerated rinse water outlet of the rinse water concentrator is communicated with the acid absorber.

[0012] Furthermore, a heat exchange cooling device is connected in series to the acid absorber.

[0013] Furthermore, the rinse water concentrator is a reverse osmosis membrane device.

[0014] The present invention also provides a zero-emission resource disposal process for pickling process waste using the above-mentioned disposal device, and the specific steps are:

[0015] The acid sludge discharged from the pickling unit is supplied to the sludge evaporator, and heat exchange is performed with the high-temperature tail gas discharged from the denitration reactor to evaporate the acid sludge to dryness, and the generated dry sludge is supplied to the grinder, and after being ground into dry sludge powder, it is added to the solid-liquid mixer;

[0016] The waste rinsing water discharged from the pickling unit is supplied to the rinsing water concentrator for concentration, the concentrated rinsing water is added to the solid-liquid mixer, and is fully mixed with the dry sludge powder added to the solid-liquid mixer by the grinder in the solid-liquid mixer, and the formed sludge mixed liquid is transported to the roasting reactor;

[0017] The waste acid discharged from the pickling unit is supplied to the roasting reactor, and undergoes high-temperature thermal hydrolysis reaction with the sludge mixed liquid supplied to the roasting reactor by the solid-liquid mixer to generate acid regeneration tail gas and metal oxides;

[0018] The metal oxides in the roasting reactor are recovered and transported out; at the same time, the acid regeneration tail gas in the roasting reactor and the tail gas of the pickling unit discharged by the pickling unit are transported to the acid absorber for acid absorption, and the acidic components in the tail gas are absorbed to form regenerated acid; the acid absorption tail gas discharged by the acid absorber is transported to the denitrification reactor for denitrification treatment, and the high-temperature tail gas after the denitrification treatment is reused in the sludge evaporator for heat exchange with the acid sludge and then discharged.

[0019] Furthermore, the sludge evaporation tail gas generated by heat exchange in the sludge evaporator is transported to the acid absorber, and is absorbed with acid together with the acid regeneration tail gas and the acid washing unit tail gas in the acid absorber, and the regenerated acid generated after absorption is reused in the acid washing unit.

[0020] Furthermore, the absorption liquid used for absorbing acid in the tail gas in the acid absorber is supplemented by the condensate produced by the heat exchange cooling device connected in series on the acid absorber or the regenerated rinsing water produced by concentrating the waste rinsing water in the rinsing water concentrator.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The zero-emission resource disposal device and process for pickling process waste provided by the present invention can completely recycle the acidic solid waste, waste liquid and waste gas generated by the pickling unit to achieve zero emission;

[0023] (2) The present invention converts metal ions in pickling sludge solid waste and pickling waste liquid into a complete resource form of metal oxides;

[0024] (3) The present invention reduces the gas temperature in the acid absorber through a heat exchange cooling device, so that a large amount of water in the gas condenses into the absorption liquid, replenishes the absorption liquid, and can complete the acid absorption by itself without additional water replenishment. At the same time, it is beneficial to the discharge of gas after it meets the standards;

[0025] (4) Using the waste heat from the denitrification reactor to heat and evaporate the acid sludge solid waste is beneficial to reducing system energy consumption;

[0026] (5) The present invention removes the moisture and free acid in the acid sludge solid waste by evaporation first, which can greatly reduce the corrosion of subsequent process equipment such as grinders. The sludge is then ground. The fully ground dry sludge powder is more conducive to the preparation of sludge mixed liquor and is easy to react and regenerate in the roasting reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 A schematic diagram of the structure of a zero-emission resource disposal device for pickling process waste provided by an embodiment of the present invention;

[0029] In the figure: 1. Pickling unit, 2. Sludge evaporator, 3. Grinder, 4. Rinse water concentrator, 5. Solid-liquid mixer, 6. Roasting reactor, 7. Acid absorber, 8. Denitrification reactor, 9. Heat exchange cooling device. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0032] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0033] like Figure 1As shown, an embodiment of the present invention provides a zero-emission resource disposal device for pickling process waste, including a pickling unit 1, a sludge evaporator 2, a grinder 3, a rinsing water concentrator 4, a solid-liquid mixer 5, a roasting reactor 6, an acid absorber 7 and a denitrification reactor 8; the acid sludge outlet of the pickling unit 1 is connected to the sludge evaporator 2, the grinder 3 and the solid-liquid mixer 5 in sequence through a material pipeline, and is used to supply the dry sludge powder formed by drying and grinding the acid sludge discharged from the pickling unit 1 into the solid-liquid mixer 5; the waste rinsing water outlet of the pickling unit 1 is connected to the rinsing water concentrator 4, and the concentrated rinsing water outlet of the rinsing water concentrator 4 is connected to the solid-liquid mixer 5, and is used to supply the concentrated rinsing water obtained by concentrating the waste rinsing water discharged from the pickling unit 1 into the solid-liquid mixer 5, and mix it with the dry sludge powder supplied into the solid-liquid mixer 5 by the grinder 3 to form a sludge mixed liquid; the waste acid of the pickling unit 1 The outlet and the material outlet of the solid-liquid mixer 5 are both connected to the material inlet of the roasting reactor 6, which are used to supply the sludge mixed liquid discharged from the solid-liquid mixer 5 and the waste acid discharged from the pickling unit 1 into the roasting reactor 6 for high-temperature thermal hydrolysis reaction to generate acid regeneration tail gas and metal oxides; the tail gas outlet of the pickling unit 1 and the tail gas outlet of the roasting reactor 6 are both connected to the acid absorber 7, which are used to transport the acid regeneration tail gas generated in the roasting reactor 6 and the pickling unit tail gas discharged from the pickling unit 1 to the acid absorber 7 for acid absorption to generate regeneration acid; the tail gas outlet of the acid absorber 7 is connected to the denitration reactor 8 and the sludge evaporator 2 in sequence through a gas pipeline, which is used to transport the acid-absorbed tail gas after acid absorption in the acid absorber 7 to the denitration reactor 8 for denitration treatment, and use the high-temperature tail gas after the denitration reaction to perform heat exchange with the acid sludge in the sludge evaporator 2 to evaporate the acid sludge.

[0034] The disposal device of this embodiment can simultaneously dispose of the acid sludge, waste rinsing water, waste acid and tail gas generated by the pickling unit, and convert the metal ions in the acid sludge and waste rinsing water into a complete resource form of metal oxides, and convert the tail gas of the high-temperature thermal hydrolysis reaction of the acid sludge, waste rinsing water and waste acid and the acidic components in the tail gas of the pickling unit into regenerated acid and recover them to achieve zero waste discharge; at the same time, since the denitrification reaction carried out in the denitrification reactor 8 is an exothermic reaction, the heat released by the denitrification reaction is used to heat and evaporate the acid sludge, which is beneficial to reducing the energy consumption of the system.

[0035] Furthermore, the sludge evaporation tail gas outlet of the sludge evaporator 2 is connected to the acid absorber 7 through a gas pipeline. In this embodiment, the sludge evaporation tail gas evaporated from the sludge evaporator 2 is transported to the acid absorber 7, and after spraying and absorption, the recoverable effective acid components in the sludge evaporation tail gas are absorbed by water to form regenerated acid.

[0036] Furthermore, the regenerated acid outlet of the acid absorber 7 is connected to the pickling unit 1. In this embodiment, the acid regeneration tail gas generated in the roasting reactor 6, the pickling unit tail gas discharged from the pickling unit 1, and the sludge evaporation tail gas evaporated from the sludge evaporator 2 are transported to the acid absorber 7 for acid absorption, and the generated regenerated acid can be reused in the pickling unit 1.

[0037] Furthermore, the rinse water concentrator 4 may be a reverse osmosis membrane device. Furthermore, the regenerated rinse water outlet of the rinse water concentrator 4 is connected to the pickling unit 1; and / or the regenerated rinse water outlet of the rinse water concentrator 4 is connected to the acid absorber 7. The rinse water concentrator of this embodiment uses reverse osmosis technology to concentrate the waste rinse water, and the concentrated liquid generated is sent to the solid-liquid mixer 5. The generated regenerated rinse water can be reused in the pickling unit 1 or used to supplement the absorption liquid in the acid absorber 7, so that the overall waste liquid volume can be ensured not to increase while the regenerated rinse water is recovered.

[0038] Furthermore, a heat exchange cooling device 9 is connected in series to the acid absorber 7. In this embodiment, the heat exchange cooling device 9 is used to reduce the gas temperature in the acid absorber 7, so that a large amount of water in the gas is condensed into the absorption liquid, and the absorption liquid is replenished. The acid absorption can be completed automatically without additional water replenishment, and at the same time, it is beneficial to the discharge of the gas after it meets the standards.

[0039] Furthermore, the sludge evaporator 2 of the present embodiment is an indirect heat exchange device. The high-temperature exhaust gas discharged from the denitrification reactor 8 enters through the heat source gas inlet of the sludge evaporator 2, undergoes indirect heat exchange with the acid sludge in the sludge evaporator 2, and is directly discharged from the cold source gas outlet of the sludge evaporator 2.

[0040] like Figure 1 As shown, this embodiment also provides a zero-emission resource disposal process for pickling process waste using the above-mentioned disposal device, and the specific steps are:

[0041] The acid sludge discharged from the pickling unit 1 is supplied to the sludge evaporator 2, and heat exchange is performed with the high-temperature tail gas discharged from the denitration reactor 8 to evaporate the acid sludge, and the generated dry sludge is supplied to the grinder 3, and after being ground into dry sludge powder, it is added to the solid-liquid mixer 5;

[0042] The waste rinsing water discharged from the pickling unit 1 is supplied to the rinsing water concentrator 4 for concentration, and the concentrated rinsing water produced is added to the solid-liquid mixer 5, and is fully mixed with the dry sludge powder added to the solid-liquid mixer 5 by the grinder 3 in the solid-liquid mixer 5, and the formed sludge mixed liquid is transported to the roasting reactor 6; the regenerated rinsing water produced in the rinsing water concentrator 4 is reused in the pickling unit 1;

[0043] The waste acid discharged from the pickling unit 1 is supplied to the roasting reactor 6, and undergoes high-temperature thermal hydrolysis reaction with the sludge mixed liquid supplied to the roasting reactor 6 by the solid-liquid mixer 5 to generate acid regeneration tail gas and metal oxides;

[0044] The metal oxides in the roasting reactor 6 are recovered and transported out; at the same time, the acid regeneration tail gas in the roasting reactor 6 and the pickling unit tail gas discharged by the pickling unit 1 are transported to the acid absorber 7 for acid absorption, and the acid components in the tail gas are absorbed to form regenerated acid; the acid absorption tail gas discharged by the acid absorber 7 is transported to the denitrification reactor 8 for denitrification treatment, and the high-temperature tail gas after the denitrification treatment is reused in the sludge evaporator 2 for heat exchange with the acid sludge, and the system tail gas after heat exchange and cooling is discharged into the atmospheric environment when it meets the standards.

[0045] Furthermore, the sludge evaporation tail gas generated by heat exchange in the sludge evaporator 2 is transported to the acid absorber 7, and is absorbed with the acid regeneration tail gas and the pickling unit tail gas in the acid absorber 7, and the regenerated acid generated after the absorption is recycled to the pickling unit 1.

[0046] Furthermore, the absorption liquid used for absorbing acid in the tail gas in the acid absorber 7 can be supplemented by the condensate produced by the heat exchange cooling device 9 connected in series with the acid absorber 7 or the regenerated rinsing water produced by concentrating the waste rinsing water in the rinsing water concentrator 4. In this embodiment, the condensate produced by the heat exchange cooling device 9 is preferably used to supplement the absorption liquid. When the condensate cannot meet the absorption liquid supplement, the regenerated rinsing water is used to supplement the absorption liquid.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A zero-emission resource disposal process for pickling process waste, characterized by: The process adopts a zero-emission resource disposal device for pickling process waste, which includes a pickling unit, a sludge evaporator, a grinder, a rinse water concentrator, a solid-liquid mixer, a roasting reactor, an acid absorber and a denitrification reactor; the acid sludge outlet of the pickling unit is connected to the sludge evaporator, the grinder and the solid-liquid mixer in sequence through a material pipeline; the waste rinse water outlet of the pickling unit is connected to the rinse water concentrator, and the concentrated rinse water outlet of the rinse water concentrator is connected to the solid-liquid mixer; the waste acid outlet of the pickling unit and the material outlet of the solid-liquid mixer are both connected to the material inlet of the roasting reactor; the tail gas outlet of the pickling unit and the tail gas outlet of the roasting reactor are both connected to the acid absorber, and the tail gas outlet of the acid absorber is connected to the denitrification reactor and the sludge evaporator in sequence through a gas pipeline; The specific steps of this process are: The acid sludge discharged from the pickling unit is supplied to the sludge evaporator, and heat exchange is performed with the high-temperature tail gas discharged from the denitration reactor to evaporate the acid sludge to dryness, and the generated dry sludge is supplied to the grinder, and after being ground into dry sludge powder, it is added to the solid-liquid mixer; the acid sludge is the acid sludge generated in the pickling process of the metallurgical industry, which contains iron oxide scale on the surface of the substrate and precipitated metal acidic compounds; The waste rinsing water discharged from the pickling unit is supplied to the rinsing water concentrator for concentration, the concentrated rinsing water is added to the solid-liquid mixer, and is fully mixed with the dry sludge powder added to the solid-liquid mixer by the grinder in the solid-liquid mixer, and the formed sludge mixed liquid is transported to the roasting reactor; The waste acid discharged from the pickling unit is supplied to the roasting reactor, and undergoes high-temperature thermal hydrolysis reaction with the sludge mixed liquid supplied to the roasting reactor by the solid-liquid mixer to generate acid regeneration tail gas and metal oxides; The metal oxides in the roasting reactor are recovered and transported out; at the same time, the acid regeneration tail gas in the roasting reactor and the tail gas of the pickling unit discharged by the pickling unit are transported to the acid absorber for acid absorption, and the acidic components in the tail gas are absorbed to form regenerated acid; the acid absorption tail gas discharged by the acid absorber is transported to the denitrification reactor for denitrification treatment, and the high-temperature tail gas after the denitrification treatment is reused in the sludge evaporator for heat exchange with the acid sludge and then discharged.

2. The zero-emission resource disposal process for pickling process waste according to claim 1, characterized in that: The sludge evaporation tail gas outlet of the sludge evaporator is connected to the acid absorber through a gas pipeline.

3. The zero-emission resource disposal process for pickling process waste according to claim 1, characterized in that: The regeneration acid outlet of the acid absorber is communicated with the pickling unit.

4. The zero-emission resource disposal process for pickling process waste according to claim 1, characterized in that: The regenerated rinse water outlet of the rinse water concentrator is communicated with the pickling unit.

5. The zero-emission resource disposal process for pickling process waste according to claim 1, characterized in that: The regenerated rinse water outlet of the rinse water concentrator is in communication with the acid absorber.

6. The zero-emission resource disposal process for pickling process waste according to claim 1, characterized in that: A heat exchange cooling device is connected in series to the acid absorber.

7. The zero-emission resource disposal process for pickling process waste according to claim 1, characterized in that: The rinse water concentrator is a reverse osmosis membrane device.

8. The zero-emission resource disposal process for pickling process waste according to claim 1, characterized in that: The sludge evaporation tail gas generated by heat exchange in the sludge evaporator is transported to the acid absorber, and is absorbed with acid together with the acid regeneration tail gas and the acid washing unit tail gas in the acid absorber, and the regenerated acid generated after absorption is recycled to the acid washing unit.

9. The zero-discharge resource disposal process for pickling process waste according to claim 1 or 8, characterized in that: The absorption liquid used for absorbing acid in tail gas in the acid absorber is supplemented by the condensate produced by the heat exchange cooling device connected in series on the acid absorber or the regenerated rinsing water produced by concentrating the waste rinsing water in the rinsing water concentrator.

Images