A sulfuric acid purification plant

Abstract

The application relates to the technical field of waste sulfuric acid recovery, and particularly discloses a sulfuric acid purification device. The device comprises a sealed heating pipe, an original acid feeding pipe for conveying sulfuric acid into the heating pipe, an acid vapor reflux pipe for recovering acid vapor at the top end of the heating pipe, and a condensing pipe connected with the acid vapor reflux pipe and used for condensing the acid vapor. The original acid feeding pipe is provided with a first preheating pipe and a second preheating pipe, the heating pipe is sleeved with the acid vapor reflux pipe, the acid vapor reflux pipe is sleeved with the second preheating pipe for raw sulfuric acid, and the lower end of the condensing pipe is sleeved with the first preheating pipe for raw sulfuric acid. The acid vapor reflux pipe is sleeved with the second preheating pipe in the mode of the heating pipe sleeving the acid vapor reflux pipe, so that the technical problem that heat energy is greatly lost in the sulfuric acid purification process, the waste sulfuric acid recovery cost is high, and the development of enterprises is restricted is solved.

Description

Technical Field

[0001] This invention relates to the field of waste sulfuric acid recovery technology, specifically to a sulfuric acid purification device. Background Technology

[0002] Sulfuric acid is an inorganic compound and the most reactive dibasic inorganic strong acid, capable of reacting with the vast majority of metals. Due to its wide range of applications, sulfuric acid is used in many industries, such as: the non-ferrous metals industry, where the purification process of flue gas from copper, lead, and zinc smelting typically employs dilute acid washing and adiabatic evaporation, generating approximately 10% waste sulfuric acid. In the iron and steel and metal pickling industry, steel wire ropes and metal products are typically cleaned with approximately 18% dilute sulfuric acid during production, producing waste sulfuric acid containing ferrous sulfate and ferric sulfate (6% content). In the petrochemical industry, waste sulfuric acid is mainly generated from petroleum refining and alkylation oil production. In petroleum refining, concentrated sulfuric acid is used to remove impurities (sulfides and unsaturated hydrocarbons) from gasoline and lubricating oil. Therefore, with the rapid development of various industries in China in recent years, the consumption of sulfuric acid has been increasing, and the amount of waste sulfuric acid generated has also been increasing year by year. If waste sulfuric acid is not recycled, it will inevitably lead to a large waste of non-metallic sulfur resources. Therefore, the resource recovery of waste sulfuric acid is becoming increasingly important.

[0003] There are generally three processes for recycling waste sulfuric acid: high-temperature pyrolysis, concentration and purification, and chemical oxidation. Concentration and purification is the most widely used due to its mature technology. The process involves first heating dilute sulfuric acid to evaporate the water, thus concentrating the waste sulfuric acid. However, the concentrated sulfuric acid still contains impurities and cannot reach reagent-grade quality. Therefore, the second step typically involves purifying the concentrated sulfuric acid using sulfuric acid purification equipment. This process involves heating the sulfuric acid to vaporize it, then condensing the vaporized sulfuric acid back into liquid sulfuric acid, thereby separating the sulfuric acid from the impurities to obtain reagent-grade sulfuric acid. However, the most crucial step in the entire process is the vaporization of the raw sulfuric acid. This step requires heating the raw sulfuric acid to its boiling point of 338 degrees Celsius. This heating process consumes a large amount of energy, resulting in high costs and hindering the development of the sulfuric acid recycling industry. Solving the problem of heat energy loss during the heating process to maximize the collection and utilization of heat energy is crucial for achieving efficient production and cost savings.

[0004] To maximize energy utilization, existing technologies utilize the characteristic that vaporized sulfuric acid needs condensation while raw sulfuric acid requires heating. This involves heat exchange between the vaporized sulfuric acid and the raw sulfuric acid, allowing the heat from the acid vapor to heat the raw sulfuric acid, thus utilizing the heat from the acid vapor. For example, patent application CN201220501437.X discloses a reagent sulfuric acid purification heating device that uses acid vapor to heat the raw sulfuric acid twice, preheating the raw material with acid vapor and making efficient use of the acid vapor's heat.

[0005] Although the aforementioned patents can utilize the heat of acid vapor, their structure is relatively loose, resulting in heat waste during the heat exchange process. Furthermore, the entire device cannot control parameters such as the heat exchange time and flow of the raw sulfuric acid, thus failing to maximize the utilization of the heat from the acid vapor and thus hinder efficient production and cost savings. Summary of the Invention

[0006] The purpose of this invention is to provide a sulfuric acid purification device to solve the technical problems mentioned above in the prior art, such as high heat loss during sulfuric acid purification, resulting in high waste sulfuric acid recycling costs and hindering enterprise development.

[0007] To solve the above problems, the technical solution adopted by the present invention is as follows: A sulfuric acid purification device includes a sealed heating tube, a raw acid feed pipe for conveying sulfuric acid into the heating tube, an acid vapor reflux pipe for recovering acid vapor from the top of the heating tube, and a condenser pipe connected to the acid vapor reflux pipe for condensing acid vapor. The raw acid feed pipe includes a first preheating tube and a second preheating tube. The acid vapor reflux pipe is sleeved inside the heating tube. The second preheating tube containing the raw sulfuric acid is sleeved in the acid vapor reflux pipe. The heating tube, the acid vapor reflux pipe, and the second preheating tube form a three-layer sleeve structure. The lower end of the condenser pipe is sleeved with the first preheating tube containing the raw sulfuric acid. The raw acid feed pipe also includes a feed inlet, which is directly connected to the first preheating tube. The diameter of the first preheating tube is twice that of the feed inlet, and the diameter of the second preheating tube is the same as that of the feed inlet.

[0008] The beneficial effects of this implementation plan are as follows:

[0009] 1. Existing heat recovery devices have a relatively loose structure, resulting in heat waste during the acid vapor heat exchange process. In contrast, this solution connects the heating pipe, acid vapor return pipe, and second preheating pipe to form a three-layer sleeve structure. The heating pipe forms an insulation layer for the acid vapor return pipe, making it easier for the heat generated by the acid vapor in the acid vapor return pipe to be dissipated. This allows the waste acid in the second preheating pipe and the heating pipe to be heated, greatly improving the heat recovery efficiency, saving energy, and reducing costs.

[0010] 2. In existing technologies, it is very difficult to control parameters such as heat exchange time and acid flow of raw sulfuric acid because the pipe diameters of the heat exchange structures are inconsistent, the required heat exchange time is also inconsistent, and the pipes are interconnected as a whole. Segmented control requires the installation of many flow control devices and sensors. However, in this solution, the diameter of the first preheating pipe is twice that of the feed inlet, and the diameter of the second preheating pipe is the same as that of the feed inlet. Therefore, it is only necessary to control the overall flow rate of waste acid entering the device to ensure that the heat exchange time of each part meets the process requirements.

[0011] Furthermore, the raw acid feed pipe also includes a feed inlet, which is directly connected to the first preheating pipe. The diameter of the first preheating pipe is twice that of the feed inlet, and the diameter of the second preheating pipe is the same as that of the feed inlet.

[0012] Furthermore, 2. The feed inlet has a diameter of 2cm, and the first preheating pipe has a diameter of 4cm.

[0013] Furthermore, the heating tube includes a straight tube with a spherical vaporization chamber at its upper end. The diameter of the spherical vaporization chamber is twice the diameter of the straight tube. A sealing column with a diameter smaller than that of the straight tube is located at the upper end of the spherical vaporization chamber. The design of the spherical vaporization chamber provides ample space above the added waste acid for vaporization, preventing acid vapor from accumulating and forming high pressure, thus facilitating the vaporization of acid vapor within the heating tube.

[0014] Furthermore, the lower end of the straight pipe has an angled opening, and a slag discharge pipe is provided downwards from the angled opening. Impurities can easily fall into the slag discharge pipe and be discharged under the influence of gravity.

[0015] Furthermore, the feed inlet is located at the lowest point of this application. Since the inlet is at the lowest point of the entire device, the raw sulfuric acid cannot enter the equipment without passing through the pump body. Therefore, the flow rate of the raw sulfuric acid in this application can be controlled by controlling the pump body, thereby controlling the inflow rate. However, when the pump body stops, the raw sulfuric acid cannot move upwards under the influence of gravity, ensuring that this application can stop and start immediately, and there is no waste of raw sulfuric acid due to production inertia when the machine stops.

[0016] Furthermore, a tail gas exhaust pipe is provided above the condenser tube. Uncondensed steam impurities after passing through the condenser tube can be discharged to the outside through the tail gas exhaust pipe. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention. Detailed Implementation

[0018] The following detailed description illustrates the specific implementation method:

[0019] The reference numerals in the accompanying drawings include: feed inlet 1, first preheating pipe 2, through pipe 3, second preheating pipe 4, heating pipe feed inlet 41, heating pipe 5, heating wire 51, spherical gasification chamber 52, slag discharge pipe 53, acid vapor reflux pipe 6, connecting reflux pipe 7, condenser pipe 8, tail gas discharge pipe 81, and reagent-grade sulfuric acid discharge pipe 82.

[0020] Implementation, for example, attached Figure 1 As shown: A sulfuric acid purification device includes a raw acid feed pipe, which includes an inlet 1, a first preheating pipe 2, a connecting pipe 3, a second preheating pipe 4, and a heating pipe inlet 41. Sulfuric acid enters the raw acid feed pipe through the inlet 1, which is a pipe with a length of 15cm at one end. The pipe opening is located at the lowest point of the entire device. Therefore, the raw sulfuric acid cannot enter the device of this application without passing through the pump body. The flow rate of the raw sulfuric acid can be controlled by controlling the pump body to control the inflow rate. However, when the pump body stops, the raw sulfuric acid cannot continue to move upward under the action of gravity, ensuring that the device can stop and start at any time without wasting raw sulfuric acid due to production inertia when the machine is stopped.

[0021] A first preheating pipe 2 is connected to the upper end of the feed inlet 1. The diameter of the first preheating pipe 2 is twice the diameter of the feed inlet 1. In this embodiment, the diameter of the feed inlet 1 is 2 cm, and the diameter of the first preheating pipe is 4 cm. Therefore, after the raw sulfuric acid enters the first preheating pipe 2, it will accumulate for a period of time before completely filling the first preheating pipe 2, so that the flow rate of the raw sulfuric acid in the first preheating pipe 2 is 1 / 2 of that inlet 1. This ensures the heat exchange time in the first preheating pipe 3. To avoid the first preheating failing to reach the specified temperature, the first preheating pipe 2 is built into the bottom of the condenser pipe 8. When the sulfuric acid in the condenser pipe 8 condenses, it will flow back to the bottom of the condenser pipe 8 under the action of gravity. Since the first preheating pipe 2 is sleeved inside the condenser pipe 8, the sulfuric acid, after condensation into liquid, is used to heat the waste acid that has just entered the equipment of this scheme for the first time through the first preheating pipe 2. Because the reagent-grade sulfuric acid outlet pipe 82, connected to the lowest point of the bottom of the condenser tube 8, is vertically upward and its opening is located at eight-tenths of the height of the first preheating tube 2, liquefied sulfuric acid will accumulate at the bottom of the condenser tube 8. It will only overflow from the equipment when the accumulated sulfuric acid level is higher than the opening of the reagent-grade sulfuric acid outlet pipe 82. Therefore, the heat exchange time between the first preheating tube 2 and the sulfuric acid is long. Furthermore, the connection between the reagent-grade sulfuric acid outlet pipe 82 and the lowest point of the bottom of the condenser tube 8 ensures that the overflowing sulfuric acid is cooled, guaranteeing the quality of heat exchange.

[0022] The first preheating pipe 2 is horizontally connected to a connecting pipe 3, the diameter of which is half that of the first preheating pipe 4, which is 2 cm in this embodiment.

[0023] The right end of the connecting pipe 3 bends upward and then vertically connects to the second preheating pipe 4. The diameter of the second preheating pipe 4 is the same as that of the connecting pipe 3. Therefore, the flow rate of the raw sulfuric acid through the second preheating pipe 4 is half that of the flow rate through the first preheating pipe 2. Thus, the heating time of the raw sulfuric acid in the second preheating pipe 4 is also half that of the first preheating pipe 2.

[0024] A transverse heating pipe inlet 41 is connected to the upper end of the second preheating pipe 4. The raw material sulfuric acid enters the heating pipe 5 through the heating pipe inlet 41. The heating pipe 5 includes a straight pipe structure with a diameter 3.5-4 times that of the first preheating pipe 2. In this embodiment, the diameter of the straight pipe structure is 14.5 cm. The lower end of the straight pipe structure is designed with a bevel, making the length of the left end shorter than the length of the right end, with the difference being 0.25-0.3 times the length of the right end. In this embodiment, the length of the left end of the straight pipe is 40 cm and the length of the right end is 55 cm, with a difference of 15 cm. Left and right; the beveled end of the straight pipe connects to the right slag discharge pipe 53. The beveled design allows the waste acid in the heating pipe 5 to settle during the heating process. Some solidified precipitates and impurities after heating can fall directly into the slag discharge pipe 53 under the action of gravity through the beveled end. The diameter of the slag discharge pipe 53 is larger than the diameter of the feed inlet. Since the raw sulfuric acid enters this application through the feed inlet 1, there cannot be impurities larger than the feed inlet 1 in the raw sulfuric acid. Therefore, the diameter of the slag discharge pipe 53 is designed to be larger than the feed inlet 1 so that impurities can easily fall into the slag discharge pipe 53 under the action of gravity.

[0025] The heating tube 5 in the straight tube structure is equipped with a heating wire 51, so after the waste acid enters the heating tube 5, it is heated into acid vapor in the straight tube structure.

[0026] A spherical vaporization chamber 52 is provided above the straight pipe. The diameter of the spherical vaporization chamber 52 is twice the diameter of the straight pipe, so in this embodiment it is 29 cm. At the upper end of the spherical vaporization chamber 52 is a sealing column, the diameter of which is smaller than the diameter of the straight pipe of the heating tube 5. In this embodiment, the diameter of the sealing column is 9.5 cm and the height is 15.5 cm.

[0027] An acid vapor return pipe 6 is fitted inside the center of the heating tube 5. The diameter of the acid vapor return pipe 6 is three times the diameter of the feed inlet 1, therefore 6 cm in this embodiment. The upper end of the acid vapor return pipe 6 is higher than the spherical vaporization chamber 52 and connects to the inside of the heating tube 5. By controlling the level of the raw sulfuric acid entering the heating tube 5 to be no higher than the bottom of the spherical vaporization chamber 52, it can be ensured that only acid vapor can flow out of the heater 5 through the acid vapor return pipe 6. The lower end of the acid vapor return pipe 6 is fitted with a second preheating pipe 4. Therefore, a three-layer sleeve structure is formed at the lower end of the heating tube 5, consisting of the heating tube 5 fitted with the acid vapor return pipe 6 and the acid vapor return pipe 6 fitted with the second preheating pipe 4. This three-layer sleeve structure allows the acid vapor return pipe 6 to heat the raw sulfuric acid in the heater 5 and preheat the raw sulfuric acid in the second preheating pipe 4. The heat transfer to the raw sulfuric acid from both inside and outside maximizes the utilization of the heat of the acid vapor.

[0028] The bottom of the heating tube 5 is penetrated through the lower end of the acid vapor return pipe 6, and the extended part is horizontally connected to the return pipe 7 to the left. The left end of the return pipe 7 is inclined downwards. This inclined design allows some acid vapor to flow into the condenser pipe 8 even if it has already condensed in the second preheating tube 4. The return pipe 7 is connected to the condenser pipe 8, which mainly uses air to condense the acid vapor. The condenser pipe 8 is a spike-shaped condenser pipe (not shown in the figure). The reagent-grade sulfuric acid condensed into liquid will drip onto the lower end of the condenser pipe 8, and the first preheating tube 2 is sleeved inside the lower end of the condenser pipe 8. Therefore, the condensed sulfuric acid can be used to preheat the raw sulfuric acid for the first time. A tail gas exhaust pipe 81 is provided at the upper end of the condenser pipe 8, so that the uncondensed vapor impurities after passing through the condenser pipe 8 can be discharged to the outside through the tail gas exhaust pipe 81.

[0029] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A sulfuric acid purification device, comprising a sealed heating tube, a raw acid feed pipe for conveying sulfuric acid into the heating tube, an acid vapor return pipe for recovering acid vapor from the top of the heating tube, and a condenser pipe connected to the acid vapor return pipe for condensing the acid vapor, characterized in that: The raw acid feed pipe includes a first preheating pipe and a second preheating pipe. An acid vapor reflux pipe is sleeved inside the heating pipe. The acid vapor reflux pipe is sleeved with the second preheating pipe containing raw sulfuric acid. The heating pipe, acid vapor reflux pipe, and second preheating pipe form a three-layer sleeve structure. The lower end of the condenser pipe is sleeved with the first preheating pipe containing raw sulfuric acid. The raw acid feed pipe also includes a feed inlet, which is directly connected to the first preheating pipe. The diameter of the first preheating pipe is twice that of the feed inlet, and the diameter of the second preheating pipe is the same as that of the feed inlet. The lower end of the acid vapor reflux pipe penetrates the bottom of the heating pipe, and its extended portion laterally connects to a return flow pipe to the left. The left end of the return flow pipe slopes downwards towards the horizontal line and is connected to the condenser pipe.

2. The sulfuric acid purification equipment according to claim 1, characterized in that: The feed inlet has a diameter of 2cm, and the first preheating pipe has a diameter of 4cm.

3. The sulfuric acid purification equipment according to claim 1, characterized in that: The heating tube includes a straight tube, the upper end of which is provided with a spherical vaporization chamber, the diameter of which is twice the diameter of the straight tube, and the upper end of which is provided with a sealing column, the diameter of which is smaller than the diameter of the straight tube.

4. The sulfuric acid purification equipment according to claim 3, characterized in that: The lower end of the straight pipe has an oblique opening, and a slag discharge pipe is provided downward from the oblique opening of the straight pipe.

5. The sulfuric acid purification equipment according to claim 1, characterized in that: The feed inlet is located at the lowest point of the entire purification equipment.

6. The sulfuric acid purification equipment according to claim 1, characterized in that: An exhaust pipe is provided above the condenser pipe.

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