TWM604391U - Safety structure of waste acid recovery roaster - Google Patents

Abstract

The invention relates to a safety structure of a waste acid recovery roasting furnace, which is a combination structure of stacking furnace bodies. The safety structure of the roasting furnace includes: a furnace bottom, a furnace middle layer, and a furnace roof. The furnace bottom, furnace middle layer, and furnace top with different furnace wall thicknesses are combined together to produce a low-cost, lightweight, and safe operation of the overall structure of the furnace body.

Description

Safety structure of waste acid recovery roaster

The model belongs to the technical field of regeneration of waste acid by spray roasting method, in particular to a safety structure of a roasting furnace.

[化2]

According to this, after filtering, pre-concentrating and pressurizing the waste mixed acid discharged from the pickling line in the stainless steel manufacturing process, it will be sprayed into the furnace from the spray gun 91 on the top of the conventional roasting furnace 9, as shown in Figure 5; There are several burners 92 around the middle section of the furnace body to spray and burn the acid mist in the furnace. The temperature of the furnace top 93 is about 303°C, the temperature of the middle section 94 is about 634°C, and the temperature of the bottom 95 is about 363°C. , And the overall negative pressure in the furnace is controlled to -0.4kpa, so that the vaporized water and free acid generated by spray roasting in the conventional roasting furnace 9 will be discharged from the channel in the roof 93, and the reaction in the furnace The chemical formulas are shown in [Chemical Formula 1] and [Chemical Formula 2]. The metal oxides produced by the calcination are transported to the discharge port of the furnace bottom 95 and discharged. Both of them can be recycled and reused after being treated separately. [化1]

[化2]

The existing conventional roasting furnace 9 has a furnace body steel plate welded with a 20mm thick 1.4876 high nickel stainless steel (namely Incoloy 800) plate. It is a roasting furnace with a uniform wall thickness, but it is found in the bottom of the furnace after several years of use. A large amount of iron oxide powder was observed outside 95. When the furnace was shut down to inspect the furnace top 93, the middle section of the furnace 94, and the furnace bottom 95, it was found that the turning point 96 between the middle section of the furnace 94 and the furnace bottom 95 became thinner and formed stress corrosion. , Resulting in cracking and affecting use.

Analysis of the main reason for the corrosion and thinning of the roasting furnace body is that most of the iron oxide powder produced by roasting waste mixed acid stays in the bottom 95 of the furnace for a long time. Because these iron oxide powders contain a small amount of nitric acid and hydrofluoric acid, It has not yet been completely evaporated, leaving these iron oxide powders at the bottom 95 of the furnace to still have fluoride ions, which will cause an additive effect under high temperature conditions, and further quickly corrode the steel plate of the bottom 95 of the furnace.

Therefore, the existing conventional roasting furnace must be guaranteed and its structure improved, and the existing conventional roasting furnace has the following problems: (1) the furnace body is easy to quickly thin, (2) the furnace body is not easy to renovate, and (3) it is difficult. Forecast and maintenance, (4) the overall replacement cost is too high, (5) difficult to combine different materials.

For this reason, in view of the problems of the aforementioned conventional roasting furnaces, the inventors worked hard to develop a safe structure for waste acid recovery roasting furnaces. Therefore, the main purpose of the present invention is to provide a lightweight, low-cost and durable A safety structure for waste acid recovery roasting furnace.

In order to achieve the above purpose, the present invention uses the following technical means: Regarding the safety structure of the new waste acid recycling roaster, it includes: a furnace bottom, which is made of heat-resistant and corrosion-resistant steel, and further includes a bottom plate and a furnace wall, and The bottom plate and the furnace wall form a turning point, and an inner lining ring is connected at the turning point, wherein the bottom circumference of the lining ring is connected to the bottom plate, and the top circumference of the lining ring is connected to the wall plate , And the lining ring and the bottom plate are made of different materials, and the lining ring and the wall plate are made of different materials; a furnace intermediate layer is made of heat-resistant and corrosion-resistant steel, and the furnace intermediate layer is combined Above the bottom of the furnace; and a furnace top, which is made of heat-resistant and corrosion-resistant steel, and combines the furnace top with the upper part of the furnace middle layer; by setting the furnace bottom, furnace middle layer, and furnace top It is a combination of different materials to produce a roasting furnace that strengthens the overall structure of the furnace body.

The bottom of the furnace, the middle layer of the furnace, and the top of the furnace are set to have the same wall thickness.

The furnace bottom has a first wall thickness (t1), the furnace middle layer has a third wall thickness (t3), and the furnace top has a fourth wall thickness (t4), and t1>t3>t4.

The furnace bottom further includes an upper furnace bottom layer and a lower furnace bottom layer, wherein the upper furnace bottom layer is combined above the lower furnace bottom layer, and the upper furnace bottom layer and the lower furnace bottom layer are set to have different outer diameters; and The upper layer of the furnace bottom further includes the bottom plate and the wall plate, and the lower layer of the furnace bottom and the bottom plate are provided with the first wall thickness (t1), and the wall plate and the inner lining ring are both set to have The second wall thickness (t2), again t1>t2>t3>t4.

There is another tube channel connected to the furnace cover layer of the furnace roof, and the tube channel is made of heat-resistant and corrosion-resistant steel with a fifth wall thickness (t5), and t1>t2>t3>t4>t5.

Among them, based on the test data of 2.5 to 3 years, several repair plates made of heat-resistant and corrosion-resistant steel were welded and joined in areas where the wall thickness had become thinner by at least half.

The heat-resistant and corrosion-resistant steel material is made of inconel (Inconel) 316L, inconel 625 or inconel 800, and the first wall thickness (t1) is set to 20mm, and the second wall thickness (t2) is set to 14 mm, the third wall thickness (t3) is 12 mm, the fourth wall thickness (t4) is 10 mm, and the fifth wall thickness (t5) is 8 mm.

With the above technical means, the present invention can achieve the following effects: 1. The safety structure of the new type of roasting furnace body is composed of furnace bottom, furnace middle layer, and furnace roof with different wall thicknesses. Relatively thin steel is used for parts that are not prone to corrosion, and relatively thick steel is used for parts that are prone to corrosion. The lining ring is used to protect the turning point of the bottom of the furnace so that it cannot form stress corrosion, so as to provide a low-cost, lightweight, and take into account the safe operation of the overall structure of the furnace body to meet the requirements of regulations. 2. This new model provides a safe structure for roasting furnaces that takes into account structural safety and light weight. Relatively thin steel is used for parts that are not prone to corrosion, and relatively thick steel is used for parts that are prone to corrosion, which can prolong the life of the roaster many times. At the same time, it saves material resources and is environmentally friendly.

First of all, please refer to Figure 1 and Figure 2. The present invention relates to a safety structure A of a waste acid recovery roasting furnace. The furnace body is formed into a layered welding joint structure, and the materials of each layer of the furnace body can be the same material. Or different materials, can also have the same wall thickness or different wall thicknesses, in order to respond to different acid recovery properties, wherein the roaster safety structure A includes: a furnace bottom 1, a furnace middle layer 2, a furnace top 3 or / And tube passage 4; as shown in Figure 2, the bottom 1 of the furnace is defined as section h1, the middle layer 2 of the furnace is defined as section h2, the top 3 is defined as section h3, and the tube passage 4 is connected to The upper part of the furnace roof 3 is described below with several embodiments.

Regarding the first embodiment of the safety structure A of the new type of roasting furnace, the furnace bottom 1, the furnace middle layer 2, and the furnace top 3 are made of the same material combination, and heat-resistant and corrosion-resistant steel materials are selected, and the furnace The bottom 1, the furnace middle layer 2, and the furnace top 3 can be set to the same wall thickness, and the preferred embodiment is that the wall thickness of the furnace bottom 1 is greater than the wall thickness of the furnace middle layer 2 and the furnace top 3; A bottom plate 121 and a furnace wall 122 provided in the bottom 1 of the furnace form a turning point 110, and an inner lining ring 13 is connected to the turning point 110, and the bottom circumference of the lining ring 13 is connected to the bottom plate 121, The top circumference of the lining ring 13 is connected to the wall 122, the lining ring 13 and the bottom plate 121 are made of different materials, and the lining ring 13 and the wall 122 are made of different materials to make A roasting furnace that strengthens the overall structure and safety of the furnace body; in particular, the aforementioned heat-resistant and corrosion-resistant steel materials are selected from high-corrosion resistant inconel 316L, inconel 625 or inconel 800 and other high nickel alloy steel plates.

Regarding the second embodiment of the safety structure A of the new type of roasting furnace, the second embodiment and the first embodiment have the same furnace body structure. The difference between the two is that the second embodiment is the furnace bottom 1, the furnace The middle layer 2 and the furnace top 3 are set to be a combination of different materials, and the high corrosion-resistant inconel 316L, inconel 625 or inconel 800 and other British high nickel alloy steel plates are selected, and the three are arranged according to the corrosion resistance. The inconel 625 is better than the inconel 800, and the inconel 800 is better than the inconel 316L.

Regarding the third embodiment of the safety structure A of the new type of roasting furnace, the furnace bottom 1, the furnace middle layer 2, and the furnace top 3 are set to different wall thicknesses; wherein the furnace bottom 1 is used with the first It is made of heat-resistant and corrosion-resistant steel with a wall thickness (t1), and the furnace bottom 1 further includes an upper furnace bottom layer 12 and a lower furnace bottom layer 11, wherein the upper furnace bottom layer 12 is welded to the upper part of the lower furnace bottom layer 11 , And the furnace bottom upper layer 12 and the furnace bottom lower layer 11 are set to have unequal diameters.

In addition, the upper layer 12 of the furnace bottom further includes a turning point 110, a bottom plate 121, and a wall plate 122. The turning point 110 is formed by combining the bottom plate 121 and the wall plate 122, and a turning point 110 is connected to it. The inner lining ring 13 is also made of heat-resistant and corrosion-resistant steel, and has the function of protecting the turning point 110 from damage due to stress corrosion caused by contact with acid medium; further , The bottom bottom layer 11 and the bottom plate 121 are set to have a first wall thickness (t1), and the wall plate 111 and the lining ring 110 are set to have a second wall thickness (t2), and the second wall thickness (t2) t2) is between the first wall thickness (t1) and the third wall thickness (t3).

The furnace middle layer 2 is made of heat-resistant and corrosion-resistant steel with a third wall thickness (t3), and the furnace middle layer 2 is welded to the upper part of the furnace bottom 1, and the third wall thickness (t3) is smaller than the first wall thickness (t1) of the bottom 1 of the furnace.

The furnace roof 3 is made of heat-resistant and corrosion-resistant steel with a fourth wall thickness (t4), and the furnace roof 3 is welded and joined to the upper part of the furnace middle layer 2, and the fourth wall thickness (t4 ) Is less than the third wall thickness (t3) of the furnace middle layer 2; further, the furnace roof 3 further includes a furnace cover layer 31, a furnace roof middle layer 32, and a furnace roof lower layer 33, wherein the furnace cover layer 31 is welded and combined It is above the furnace roof middle layer 32, and the furnace roof middle layer 32 is welded and joined to the upper furnace roof lower layer 33.

The tube channel 4 is welded and joined to the furnace cover layer 31 of the furnace roof 3 as a channel for vaporized water and free acid generated by spray roasting, and the tube channel 4 has a fifth wall thickness (t5) It is made of heat-resistant and corrosion-resistant steel, and the fifth wall thickness (t5) is smaller than the fourth wall thickness (t4).

In view of the fact that the lower part of the roasting furnace is easily corroded and damaged, the safety structure A of the new roasting furnace is mainly to weld together the furnace bottom 1, furnace middle layer 2, furnace roof 3, or/and pipe channel 4 with different furnace wall thicknesses. In particular, the thickness of the new type of roasting furnace is reduced from bottom to top (t1>t2>t3>t4>t5) to produce a low-cost, lightweight, and safe operation of the overall structure of the furnace; In addition, the above-mentioned heat-resistant and corrosion-resistant steel materials are preferably selected as high-corrosion resistant inconel 316L, inconel 625 or inconel 800 and other Anglo-nickel alloy steel materials. The wall thickness (t1) is preferably set to 20mm, the second wall thickness (t2) is preferably set to 14mm, the third wall thickness (t3) is preferably set to 12mm, and the fourth wall thickness (t4) It is preferably set to 10 mm, and the fifth wall thickness (t5) is preferably set to 8 mm. 【Table 1】 project Furnace body part Thickness(mm) Use heat and corrosion resistant materials 1 The bottom of the furnace 11 t1=20 inconel 316L 2 Base plate 121 t1=20 inconel 800 3 Turning point 110 t2=14 inconel 800 4 Lining ring 13 t2=14 inconel 800 5 Siding 122 t2=14 inconel 800 6 Furnace middle layer 2 t3=12 inconel 800 7 Lower floor 33 t4=10 inconel 800 8 Furnace top middle layer 32 t4=10 inconel 316L 9 Furnace cover 31 t4=10 inconel 316L 10 Tube channel 4 t5=8 inconel 316L

Please refer to Figures 3 and 4. Regarding the safety repair method B of the new type of waste acid recovery roasting furnace, it mainly provides repairing the thinning area 5 of the furnace wall of the roasting furnace to avoid the overall replacement of the roasting furnace. It includes: : A furnace body inspection step a, a repairing plate step b, a welding and joining step c or/and a weld bead inspection step d.

The furnace body detection step a is to obtain the area where the wall thickness of the roasting furnace is at least half thinner by observation or instrument measurement; the observation method is to observe that the operating power of the exhaust gas exhaust fan is increased from 82% to 90%, And a large amount of iron oxide powder was observed on the outside of the furnace bottom 95; while the instrument measurement type was used to stop the furnace and use an ultrasonic thickness gauge to check the wall thickness of the furnace top 93, the middle section of the furnace 94, and the furnace bottom 95 .

The step b of taking the repairing plate is to take several repairing plates 6 of heat-resistant and corrosion-resistant steel, and the repairing plate 6 is preferably the same material as the original furnace; further, the length and width of the repairing plate 6 is set to 900mm*900mm , And carry it into the furnace from the furnace door for attachment welding, and the repair plate 6 is made of inconel 316L, inconel 625 or inconel 800 and other inconel alloy materials.

In the welding and joining step c, the repairing plates 6 are welded and arranged in the thinned area 5 of the furnace wall, as shown in FIG. 4, and constructed by a direct current welding machine, and the electrode used is GNC112- 4.0mm nickel-based welding rod; in other words, the weld bead 7 is spread around the repaired plates 6 and the gaps; in particular, the thinned area 5 of the furnace wall may be the entire furnace wall or a local part of the furnace body.

The weld bead detection step d is to detect all the weld beads 7 in the welding bonding step c by non-destructive testing (Penetrant Testing, PT) to ensure the safety of the repaired part.

Through the above steps, a low-cost, periodic repair method is provided to extend the service life of the roasting furnace, so as to reduce the maintenance cost of the roasting equipment, save resources and materials and environmental protection requirements; further, put the safety structure A of the new roaster into actual production The experiment was conducted for a total of three years. After nearly two years (time T~time T2), the wall thickness of the furnace body was measured regularly with an ultrasonic thickness gauge every one and a half months, and the following table 2 and table 3 were obtained. The wall thickness measurement data shown (unit: mm), of which Table 3 continues Table 2 and adds (3.1), (4.1), (4.2), (5.1), (5.2) the furnace body wall thickness detection The oblique line in Table 2 and Table 3 means that the furnace body does not need to be measured. 【Table 2】 Test items Furnace body part Time T (put into production line) Time T1 Time T2 repair Time T3 Time T4 Time T5 (1) Tube channel 4 8 9 8 8 8 (2) Furnace cover 31 10 9 6.3 6.4 6.3 6.3 (3) Furnace top middle layer 32 10 9.8 8.2 8.1 8 8 (4) Lower floor 33 10 10 10 (5) Furnace middle layer 2 12 12 12 (6) Siding 122 14 14 14 14 14 (7) Lining ring 13 14 4.5 3 Use patch panels (inconel 625) 10.7 10.6 10.6 (8) Turning point 110 14 14 14 (9) Base plate 121 20 7.4 0.5 Use patch panels (inconel 625) 10.7 10.7 10.5 (10) The bottom of the furnace 11 20 20 20 【table 3】 Test items Furnace body part T time (put into production line) Time T6 Time T7 Time T8 repair Time T9 (1) Tube channel 4 8 8 8 7.8 7.8 7.6 (2) Furnace cover 31 10 6.3 6.3 4.7 4.6 (3) Furnace top middle layer 32 10 8 8 7.9 7.5 (3.1) Furnace roof middle layer 32 (10 cm away from the lower weld bead) 10 5 Use patch panels (inconel 625) 10 (4) Lower floor 33 10 10 7.5 10 (4.1) Lower layer of furnace roof 33 (10 cm away from upper weld bead) 10 10 Use patch panels (inconel 625) 10 (4.2) Lower layer of furnace roof 33 (10 cm away from the lower weld bead) 10 10 10 (5) Furnace middle layer 2 12 12 12 (5.1) Furnace middle layer 2 (10 cm away from the upper weld bead) 12 11 11 (5.2) Intermediate layer 2 (10 cm away from the lower weld bead) 12 12 12 (6) Siding 122 14 14 14 14 14 14 (7) Lining ring 13 14 10.3 10.2 10.5 10.4 (8) Turning point 110 14 14 (9) Base plate 121 20 10.3 10 10.3 10 (10) The bottom of the furnace 11 20 20 20

From Table 2 and Table 3 above, it can be known that the new type of roasting furnace in the trial operation, the bottom plate 121, the liner ring 13 and other parts of the corrosion and thinning rate are faster, about 2 years of operation (time T ~ time T2), the bottom plate 121 is left from the original thickness of 20mm to 0.5mm, and the lining ring 13 is left from the original thickness of 14mm to 3mm. Therefore, the new type of baking furnace safety repair method B can be used for the bottom plate 121, lining ring 13 and other parts Several repair plates 6 made of inconel 625 are welded and repaired until the thickness of the bottom plate 121 and the inner lining ring 13 is restored to 10.8mm. After about another year (time T3~time T9) of operation, the thickness of the bottom plate 121 is still The thickness of the lining ring 13 is still 10mm, and the thickness of the lining ring 13 is still 10mm. Therefore, the periodic use of the new type of roasting furnace safety repair method B can indeed prolong the service life of the roasting furnace many times and avoid replacing the whole roasting furnace.

In the same way, item (3.1) of the wall thickness inspection of the new type of baking furnace, that is, the middle layer 32 of the furnace roof is easily thinner at 10 cm away from the lower weld bead. The test operation time is about 2.5 years (time T~time T8). The part is left from the original 10mm to 5mm, so the repairing method B of the new type of roasting furnace can be used at this time. In other words, the new type of roasting furnace safety repairing method B is not only applicable to the new type of roasting furnace, but also suitable for repairing other conventional roasting furnaces; From the above table 2 and table 3, it can be known that the turning point 110 of the furnace bottom 1 has been used for 3 years (time T~time T9), and there is no cracking and damage due to stress corrosion. The structure of the backing ring 13 does protect the turning point 110.

In addition, using the new type of roasting furnace safety repair method B for the thinning of the furnace bottom 1 part of the furnace bottom 1 using the repair plate 6 made of inconel 625 after repairing, let it return to 10.7mm thickness, and after the repair test operation use about After more than 1 year (time T3~time T9), the thickness is still 10.4mm. It can be seen that the part after repairing by the new type of roaster safety repair method B, the corrosion and thinning rate is slower than the original, so the new type of roaster Safety repair method B is the best and simple method for repairing roasting furnace in the industry.

Therefore, the new type of roasting furnace is actually put into production. After three years of tests (time T~time T9), it is indeed found that the bottom 1 of the roasting furnace corrodes and thins faster, followed by the top 3 and the middle of the furnace. Layer 2 is hardly affected by acid corrosion. Therefore, the third embodiment of the present invention uses furnace layers of different materials and different thicknesses, and the structure of the lining ring 13 at the turning point 110 in the furnace can be used as reinforcement A better solution for the safety of the roaster body structure.

A: Safety structure of roaster B: Roaster safety repair method a: steps b: step c: steps d: steps 1: furnace bottom 11: The bottom of the furnace 110: turning point 12: The upper floor of the furnace bottom 121: bottom plate 122: siding 13: Lining ring 2: Furnace middle layer 3: stove top 31: Furnace cover 32: Furnace top middle layer 33: The bottom of the stove top 4: Tube channel 5: Thinning area 6: Repair the board 7: Weld bead 9: Custom roaster 91: spray gun 92: burner 93: stove top 94: At the middle of the furnace 95: stove bottom 96: Turning Point

Figure 1: It is a three-dimensional appearance view of the safety structure of the new type of waste acid recycling roaster. Figure 2: is a cross-sectional view of the safety structure of the new type of waste acid recovery roaster. Figure 3: This is a step-by-step flow chart of the new type of waste acid recovery roaster safety repair method. Figure 4 is a schematic diagram of the implementation of the new safety repair method for the waste acid recovery roaster. Figure 5: is a schematic diagram of a conventional roasting furnace.

A: Safety structure of roaster

1: furnace bottom

11: The bottom of the furnace

110: turning point

12: The upper floor of the furnace bottom

2: Furnace middle layer

3: stove top

31: Furnace cover

32: Furnace top middle layer

33: The bottom of the stove top

Claims (7)

A safety structure of waste acid recycling roaster, which contains: A furnace bottom is made of heat-resistant and corrosion-resistant steel and further includes a bottom plate and a furnace wall. The bottom plate and the furnace wall form a turning point, and an inner lining ring is connected to the turning point, wherein the inner lining ring The bottom circumference of the lining ring is connected to the bottom plate, and the top circumference of the lining ring is connected to the wall plate, and the lining ring and the bottom plate are made of different materials, and the lining ring and the wall plate are made of different materials ； A furnace middle layer is made of heat-resistant and corrosion-resistant steel, and the furnace middle layer is bonded to the top of the furnace bottom; and A furnace roof is made of heat-resistant and corrosion-resistant steel, and the furnace roof is combined above the middle layer of the furnace; The furnace bottom, furnace middle layer, and furnace top are combined with different materials to produce a roasting furnace that strengthens the overall structure of the furnace body. The safety structure of the waste acid recovery roasting furnace according to claim 1, wherein the bottom of the furnace, the middle layer of the furnace, and the top of the furnace are set to have the same wall thickness. The safety structure of the waste acid recovery roasting furnace according to claim 1, wherein the furnace bottom has a first wall thickness (t1), the furnace middle layer has a third wall thickness (t3), and the furnace top has a fourth wall thickness (t4), again t1>t3>t4. The safety structure of the waste acid recovery roasting furnace according to claim 3, wherein the furnace bottom further includes an upper furnace bottom layer and a lower furnace bottom layer, wherein the upper furnace bottom layer is combined above the lower furnace bottom layer, and the upper furnace bottom layer The lower layer of the furnace bottom is set to have different outer diameters; and the upper layer of the furnace bottom further includes the bottom plate and the wall plate, and the bottom layer of the furnace bottom and the bottom plate are provided with the first wall thickness (t1), and the wall The plate and the inner lining ring are both set to have a second wall thickness (t2), and t1>t2>t3>t4. The safety structure of the waste acid recovery roasting furnace according to claim 4, in which a pipe channel is connected to the furnace cover layer of the furnace roof, and the pipe channel is made of heat-resistant and corrosion-resistant steel with a fifth wall thickness (t5) , And t1>t2>t3>t4>t5. According to the safety structure of the waste acid recovery roaster described in claim 1, based on the test operation data of 2.5 to 3 years, several repair plates made of heat-resistant and corrosion-resistant steel are welded and joined in areas where the wall thickness is thinned by at least half. For example, the safety structure of the waste acid recycling roaster described in any one of claim 1 to claim 6, wherein the heat-resistant and corrosion-resistant steel is made of inconel 316L, inconel 625 or inconel 800, and the first wall thickness (t1) Set to 20mm, the second wall thickness (t2) to 14mm, the third wall thickness (t3) to 12mm, the fourth wall thickness (t4) to 10mm, and the fifth wall thickness (t5) to 8mm.

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