Separation system and separation method of nitrotoluene / waste acid mixed solution

Abstract

The invention relates to the technical field of chemical product separation, and discloses a separation system and a separation method of nitrotoluene / waste acid mixed liquor. The separation system comprises a rotary drum, a central pipe, a disc group, a heavy liquid outlet and a light liquid outlet, the disc group is formed by superposing a plurality of umbrella-shaped discs at equal intervals, and neutral holes are formed in the umbrella-shaped discs; a heavy liquid channel is formed between the edge, far away from the central pipe, of the disc group and the inner wall of the rotary drum and is used for discharging waste acid; a light liquid channel is formed between the edge, close to the central pipe, of the disc group and the outer wall of the central pipe and is used for discharging nitrotoluene; a pore plate is arranged between every two adjacent umbrella-shaped discs, the number of holes in each pore plate is 10-50, and the hole diameter of each hole is 0.01-0.08 mm. The pore plate is arranged between the umbrella-shaped discs, the size of the pore plate is smaller than a flame chain reaction propagation free path, the effect of quenching flames is achieved, the safety of the production process can be improved, and the separation efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of separation of chemical products, and particularly to a separation system and a separation method for a nitro - toluene / waste acid mixture. Background Art

[0002] Nitro - toluene is one of the main components in double - base gunpowder and modified gunpowder, and occupies an extremely important position in industry and military. However, nitro - toluene is also a highly sensitive dangerous good, and there is a risk of explosion in production and use, and its accident frequency ranks first among fire - explosive accidents. Through investigation and analysis, it is found that the safe production of nitro - toluene is highly related to the production process and the operation level of operators. It is feasible to reduce safety accidents and avoid dangers by improving the production process and enhancing the qualities of operators (safety awareness, operation ability, and abnormal situation handling ability).

[0003] In the workshop production process of the nitrification process, the self - decomposition of nitro - toluene is one of the main factors causing accident risks. When the material addition amount exceeds the specified ratio or the separation of the nitrification product from the waste acid is not timely, the nitrification internal solution will self - decompose, accompanied by an oxidation - decomposition reaction, causing the temperature to rise sharply. If the temperature cannot be controlled in time, an explosion will occur. Separation and washing are both the main process steps in the production of nitro - toluene and are key processes in production. The separation and washing conditions largely determine production safety, yield, and quality.

[0004] The Nanjing Chemical Industry Group Research Institute has published a series of patent applications for the separation and washing of nitrated compounds (CN102675118A, CN103664629A, CN106278903A). These mainly focus on the development of the separation and washing processes for nitro - benzene and nitro - chlorobenzene. The static separation of nitrated compounds (oil phase) and waste acid (water phase) is achieved through a coalescing separator, and then counter - current mixing washing is carried out by means of centrifugal extraction. This method reduces the floor area of equipment and focuses more on the design and optimization of the process, but it cannot improve process safety.

[0005] Through the analysis and summary of domestic and foreign patent literatures, it is found that the separation and washing technology of nitrated compounds was initially mainly based on the combined process technology of gravity sedimentation and static mixing washing. The main problem is poor safety. Since the nitrated compounds and the waste acid are in an emulsified state after the nitrification reaction, the two phases should be separated quickly to promptly carry out the stabilization treatment of the acidic nitrated compounds, which is directly related to the safety of nitrated compound production, product quality, and production efficiency. At present, both domestic and foreign, most nitrification process technologies rely on gravity to separate the nitrification product from the waste acid, and the separation time of gravity sedimentation is long and the separation efficiency is low. Summary of the Invention

[0006] The object of the present invention is to overcome the problems existing in the prior art that when the nitrification process technology relies on gravity sedimentation to separate the nitrification product from the waste acid, the separation time of the nitrification product and the waste acid is long and the separation efficiency is low. A separation system and a separation method for a nitro - toluene / waste acid mixture are provided. The separation system and the separation method for the nitro - toluene / waste acid mixture can improve the process safety and separation efficiency, reduce the separation time of the nitro - toluene / waste acid mixture, and realize the flexible control of the process and market adaptability.

[0007] To achieve the above object, on the one hand, the present invention provides a separation system for a nitro - toluene / waste acid mixture. The separation system includes a drum, a central tube, a disc stack, a heavy - liquid outlet, and a light - liquid outlet; the disc stack is formed by equidistantly stacking a plurality of umbrella - shaped discs, and neutral holes are provided on the umbrella - shaped discs; a heavy - liquid channel is formed between the edge of the disc stack far from the central tube and the inner wall of the drum for discharging waste acid; a light - liquid channel is formed between the edge of the disc stack close to the central tube and the outer wall of the central tube for discharging nitro - toluene; a perforated plate is arranged between adjacent umbrella - shaped discs, the number of openings on the perforated plate is 10 - 50, and the diameter of the openings is 0.01 - 0.08 mm.

[0008] Preferably, the number of the perforated plates 5 equidistantly arranged between adjacent umbrella - shaped discs is 5 - 10.

[0009] Preferably, the number of horizontal openings on the perforated plate is 5 - 10, and the number of vertical openings on the perforated plate is 2 - 5.

[0010] Preferably, the shape of the openings on the perforated plate is a round hole, an oval hole, or a square hole.

[0011] Preferably, the number of the umbrella - shaped discs in the disc stack is 50 - 100.

[0012] Preferably, the vertical distance between adjacent umbrella - shaped discs is 0.1 - 1 mm.

[0013] Preferably, the thickness of the umbrella - shaped disc is 0.1 - 0.5 mm.

[0014] Preferably, the neutral holes are round holes, and the diameter of the neutral holes is 100 - 300 mm.

[0015] Preferably, the separation system further includes a jacket, and the jacket is sleeved outside the drum.

[0016] Preferably, a cooling device is provided on the jacket, and the cooling device is used to cool down the drum.

[0017] The second aspect of the present invention provides a method for separating a nitro - toluene / waste - acid mixture, which is implemented in the above - mentioned separation system for the nitro - toluene / waste - acid mixture. The separation method includes the following steps:

[0018] (1) Inject the nitro - toluene / waste - acid mixture from the inlet of the central tube into the bottom of the rotating drum. The nitro - toluene / waste - acid mixture flows upward through the neutral holes and enters between adjacent umbrella - shaped discs;

[0019] (2) The waste acid passes through the orifice plate along the lower surface of the umbrella - shaped disc and enters the heavy - liquid gap, and is discharged from the heavy - liquid outlet; the nitro - toluene passes through the orifice plate along the upper surface of the umbrella - shaped disc and enters the light - liquid gap, and is discharged from the light - liquid outlet.

[0020] Preferably, the rotational speed of the rotating drum is 1600 - 3200 r / min.

[0021] Preferably, the nitro - toluene / waste - acid mixture contains nitro - toluene and waste acid, and the volume ratio of nitro - toluene to waste acid is 1:(0.5 - 0.7).

[0022] Preferably, the flow rate of the nitro - toluene / waste - acid mixture is 100 - 1000 L / h.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] (1) In the separation system for the nitro - toluene / waste - acid mixture of the present invention, an orifice plate is arranged between the umbrella - shaped discs. The pore size on the orifice plate is smaller than the free path of flame - chain reaction propagation, which plays a role in quenching the flame, can improve the safety of the production process, and improve the separation efficiency;

[0025] (2) In the separation system for the nitro - toluene / waste - acid mixture of the present invention, a jacket is arranged outside the rotating drum, and the cooling device on the jacket can take away the heat generated by the rotating drum to prevent energy accumulation;

[0026] (3) In the separation method for the nitro - toluene / waste - acid mixture of the present invention, the concept of process intensification - high - gravity acceleration is adopted to separate the nitro - toluene / waste - acid mixture, which can shorten the separation time, improve the separation efficiency, and realize the essential safety upgrade of the nitration process. Description of the Drawings

[0027] Figure 1 It is a schematic diagram of the separation system for the nitro - toluene / waste - acid mixture.

[0028] Description of the Reference Numerals

[0029] 1. Rotating drum; 2. Central tube; 3. Neutral hole; 4. Disc group; 5. Orifice plate; 6. Heavy - liquid outlet; 7. Light - liquid outlet; 8. Jacket. Detailed Embodiments

[0030] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not intended to limit the present invention.

[0031] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range and a single point value, and between single point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0032] On the one hand, the present invention provides a separation system for a nitro - toluene / waste acid mixture, as Figure 1 shown. The separation system includes a drum 1, a central tube 2, a disc stack 4, a heavy - liquid outlet 6, and a light - liquid outlet 7; the disc stack 4 is formed by equidistantly stacking a plurality of umbrella - shaped discs, and neutral holes 3 are provided on the umbrella - shaped discs; a heavy - liquid channel is formed between the edge of the disc stack 4 far from the central tube 2 and the inner wall of the drum 1 for discharging waste acid; a light - liquid channel is formed between the edge of the disc stack 4 close to the central tube 2 and the outer wall of the central tube 2 for discharging nitro - toluene.

[0033] In the separation system of the present invention, in order to provide sufficient installation space for the central tube 2 and the disc stack 4, and sufficient flow space for the nitro - toluene / waste acid mixture, the inner diameter of the drum 1 is 100 - 300 mm. Specifically, the inner diameter of the drum 1 can be 100 mm, 150 mm, 200 mm, 250 mm, or 300 mm.

[0034] In the separation system of the present invention, in order to keep the drum 1 balanced during operation, the central tube 2 is arranged on the central axis of the drum 1, and the shape of the central tube 2 is a cube or a cylinder. In a specific embodiment, the shape of the central tube 2 is a cylinder, and the diameter of the bottom surface of the cylinder is 10 - 100 mm. Specifically, the diameter of the bottom surface of the cylinder can be 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, or 100 mm.

[0035] In the separation system of the present invention, in order to promote the flow of the nitrotoluene / waste acid mixture, the umbrella-shaped disc is inclined, and the angle between the upper surface of the umbrella-shaped disc and the central tube 2 is 105°-135°. Specifically, the angle between the upper surface of the umbrella-shaped disc and the central tube 2 can be 105°, 110°, 115°, 120°, 125°, 130° or 135°.

[0036] In the separation system of the present invention, the light liquid outlet 7 is arranged on the side of the central tube 2. In a specific embodiment, the number of the light liquid outlets 7 is two, and the two light liquid outlets 7 are symmetrically arranged on both sides of the central tube 2.

[0037] In the separation system of the present invention, the heavy liquid outlet 6 is arranged on the side of the light liquid outlet 7. In a specific embodiment, the number of the heavy liquid outlets 6 is two, and the two heavy liquid outlets 6 are symmetrically arranged on the sides of the two light liquid outlets 7.

[0038] In the separation system of the present invention, since free radical collisions occur during the flow of the nitrotoluene / waste acid mixture, heat is released and combustion produces flames. When the flames propagate in a slit or a narrow channel, if the spacing of the slit or the diameter of the channel is small enough, the flames will automatically go out after propagating a certain distance. To suppress the flame propagation, an orifice plate 5 is arranged between adjacent umbrella-shaped discs, and the orifice plate 5 is used to provide a flow channel for the nitrotoluene / waste acid mixture.

[0039] In the separation system of the present invention, the number of openings on the orifice plate 5 is 10-50. Specifically, the number of openings on the orifice plate 5 can be 10, 20, 30, 40 or 50.

[0040] In a specific embodiment, in order to allow more nitrotoluene / waste acid mixture to flow through the openings, the orifice plate 5 is vertically arranged between adjacent umbrella-shaped discs, and the nitrotoluene / waste acid mixture flows through the openings on the orifice plate 5.

[0041] In the separation system of the present invention, the shape of the openings on the orifice plate 5 is a round hole, an oval hole or a square hole, and the diameter of the openings is 0.01-0.08 mm.

[0042] In a specific embodiment of the present invention, the shape of the openings on the orifice plate 5 is a round hole, and the diameter of the round hole is 0.01-0.08 mm. Specifically, the diameter of the round hole can be 0.01 mm, 0.02 mm, 0.04 mm, 0.06 mm or 0.08 mm.

[0043] In another specific embodiment of the present invention, the opening shape on the orifice plate 5 is a square hole, and the side length of the square hole is 0.01 - 0.08 mm. Specifically, the side length of the square hole can be 0.01 mm, 0.02 mm, 0.04 mm, 0.06 mm, or 0.08 mm.

[0044] In still another specific embodiment of the present invention, the opening shape on the orifice plate 5 is an oval hole, the major axis of the oval hole is 0.01 - 0.04 mm, and the minor axis of the oval hole is 0.05 - 0.08 mm.

[0045] In the separation system of the present invention, the number of the orifice plates (5) equidistantly arranged between adjacent umbrella-shaped discs is 5 - 10.

[0046] In the separation system of the present invention, in order to further suppress flame propagation, the number of transverse openings on the orifice plate 5 is 5 - 10, and the number of longitudinal openings on the orifice plate 5 is 2 - 5. Specifically, the number of transverse openings on the orifice plate 5 can be 5, 6, 7, 8, 9, or 10, and the number of longitudinal openings on the orifice plate 5 can be 2, 3, 4, or 5.

[0047] In the separation system of the present invention, the distance between the two ends of the umbrella-shaped discs in the disc group 4 is 30 - 120 mm. Specifically, the distance between the two ends of the umbrella-shaped discs in the disc group 4 can be 30 mm, 60 mm, 90 mm, or 120 mm.

[0048] In the separation system of the present invention, the number of the umbrella-shaped discs in the disc group 4 is 50 - 100. Specifically, the number of the umbrella-shaped discs in the disc group 4 can be 50, 60, 70, 80, 90, or 100.

[0049] In the separation system of the present invention, the vertical distance between adjacent umbrella-shaped discs is 0.2 - 1.5 mm. Specifically, the vertical distance between adjacent umbrella-shaped discs can be 0.2 mm, 0.5 mm, 1 mm, or 1.5 mm.

[0050] In the separation system of the present invention, the thickness of the umbrella-shaped disc is 0.1 - 0.5 mm. Specifically, the thickness of the umbrella-shaped disc can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm.

[0051] In the separation system of the present invention, the neutral hole 3 is a round hole, and the diameter of the neutral hole 3 is 100 - 300 mm. Specifically, the diameter of the neutral hole 3 can be 100 mm, 150 mm, 200 mm, 250 mm, or 300 mm.

[0052] In the separation system of the present invention, a heavy liquid channel is formed between the edge of the disc stack 4 away from the central tube 2 and the inner wall of the drum 1, and the waste acid is discharged from the heavy liquid outlet 6 through the heavy liquid channel.

[0053] In the separation system of the present invention, the heavy liquid outlet 6 is circular, and the diameter of the heavy liquid outlet 6 is 80 - 150 mm. Specifically, the diameter of the heavy liquid outlet 6 can be 80 mm, 90 mm, 100 mm, 110 mm, 120 mm, 130 mm, 140 mm or 150 mm.

[0054] In the separation system of the present invention, a light liquid channel is formed between the edge of the disc stack 4 close to the central tube 2 and the outer wall of the central tube 2, and the nitrotoluene is discharged from the light liquid outlet 7 through the light liquid channel.

[0055] In the separation system of the present invention, the light liquid outlet 7 is circular, and the diameter of the light liquid outlet 7 is 50 - 100 mm. Specifically, the diameter of the light liquid outlet 7 can be 50 mm, 60 mm, 70 mm, 80 mm, 90 mm or 100 mm.

[0056] In the separation system of the present invention, heat is generated by friction during the rotation of the drum 1, and the heat can cause the decomposition of nitrates. To cool the drum 1, the separation system further includes a jacket 8 sleeved outside the drum 1, and a cooling device is provided on the jacket 8 for cooling the drum 1.

[0057] In the separation system of the present invention, a cooling medium is filled in the cooling device. The cooling effect of the cooling medium is related to the specific heat. The higher the specific heat, the better the cooling effect. The cooling medium is selected from one or more of water, oil or salt. The weight ratio of the amounts of water, oil and salt is 1:(0.7 - 0.9):(1.5 - 1.9). Specifically, the weight ratio of the amounts of water, oil and salt can be 1:0.7:1.5, 1:0.8:1.6 or 1:0.9:1.9.

[0058] In the separation system of the present invention, the oil is selected from one or more of methyl silicone oil, polydimethylsiloxane, organic phosphate ester, paraffin, mineral oil and phenolic resin; the salt is selected from one or more of sodium sulfate, sodium chloride, potassium chloride and potassium nitrate.

[0059] In the preferred case of the present invention, the cooling medium of the cooling device is a mixture of water, oil and salt.

[0060] In the separation system of the present invention, the jacket 8 does not rotate with the drum 1.

[0061] The second aspect of the present invention provides a method for separating a nitrotoluene / waste acid mixture, which is implemented in the above-mentioned separation system for nitrotoluene / waste acid mixture. The separation method includes the following steps:

[0062] (1) Inject the nitrotoluene / waste acid mixture from the inlet of the central tube 2 into the bottom of the drum 1. The nitrotoluene / waste acid mixture flows upward through the neutral hole 3 and enters between adjacent umbrella-shaped discs;

[0063] (2) The waste acid passes through the orifice plate 5 along the lower surface of the umbrella-shaped disc and enters the heavy liquid gap, and is discharged from the heavy liquid outlet 6; the nitrotoluene passes through the orifice plate 5 along the upper surface of the umbrella-shaped disc and enters the light liquid gap, and is discharged from the light liquid outlet 7.

[0064] In the separation method of the present invention, in step (1), the inlet of the central tube 2 is the end of the central tube 2 extending out of the drum 1.

[0065] In the separation method of the present invention, based on the density difference between nitrotoluene and waste acid, in steps (1) and (2), the rotation speed of the drum 1 is 1600 - 3200 r / min. Specifically, the rotation speed of the drum 1 can be 1600 r / min, 2000 r / min, 2400 r / min, 2800 r / min or 3200 r / min.

[0066] In the separation method of the present invention, in steps (1) and (2), the nitrotoluene / waste acid mixture contains nitrotoluene and waste acid, and the volume ratio of nitrotoluene to waste acid is 1:(0.5 - 0.7). Specifically, the volume ratio of nitrotoluene to waste acid can be 1:0.5, 1:0.6 or 1:0.7.

[0067] In the separation method of the present invention, in order to enable the drum 1 to accommodate the nitrotoluene / waste acid mixture, in steps (1) and (2), the flow rate of the nitrotoluene / waste acid mixture is 100 - 1000 L / h. Specifically, the flow rate of the nitrotoluene / waste acid mixture can be 100 L / h, 200 L / h, 300 L / h, 400 L / h, 500 L / h, 600 L / h, 700 L / h, 800 L / h, 900 L / h or 1000 L / h.

[0068] In the separation method of the present invention, in steps (1) and (2), the centrifugal force of the drum 1 is 500 - 2710 kg. Specifically, the centrifugal force of the drum 1 can be 500 kg, 1000 kg, 1500 kg, 2000 kg, 2500 kg or 2710 kg.

[0069] In the separation method of the present invention, in steps (1) and (2), since the distance between the umbrella-shaped discs is very small, the incoming nitro toluene / waste acid mixture is divided into many very thin liquid layers.

[0070] In the separation method of the present invention, the nitro toluene / waste acid mixture will continue to undergo a nitration reaction during the flow process, thus releasing heat and decomposing and burning. In order to inhibit flame propagation, a perforated plate 5 is provided between adjacent umbrella-shaped discs. A number of openings are provided on the perforated plate 5, and the openings are used to provide a flow channel for the nitro toluene / waste acid mixture. Since the openings on the perforated plate 5 are very small, the flame will automatically go out after propagating a certain distance in the narrow channels. Therefore, after the nitro toluene / waste acid mixture enters the space between adjacent umbrella-shaped discs, it flows through the openings on the perforated plate 5, thereby inhibiting flame propagation and achieving the purpose of intrinsic safety; at the same time, since the nitro toluene / waste acid mixture flows through the openings on the perforated plate 5, the number of free radical collisions is reduced, and the loss of nitro toluene and waste acid during the flow process is small or there is no loss, so the separation efficiency is also improved.

[0071] In the separation method of the present invention, in steps (1) and (2), since the densities of nitro toluene and waste acid contained in the nitro toluene / waste acid mixture are different, the centrifugal forces acting on the nitro toluene and waste acid in the drum 1 are also different. In the gap between the umbrella-shaped discs, the waste acid flows downward and outward through the openings on the perforated plate 5 along the lower surface of the umbrella-shaped discs; the nitro toluene is subjected to a centripetal buoyancy force due to the reaction force of the centrifugal force of the outer waste acid. Under the action of the centripetal buoyancy force, the nitro toluene flows upward and inward through the openings on the perforated plate 5 along the upper surface of the umbrella-shaped discs. Finally, the heavy liquid waste acid accumulates in the heavy liquid channel, and the waste acid is discharged from the heavy liquid outlet 6 through the heavy liquid channel; the nitro toluene accumulates in the light liquid channel, and the nitro toluene is discharged from the light liquid outlet 7 through the light liquid channel, thereby achieving the purpose of separation.

[0072] In the preferred separation method of the present invention, a jacket 8 is sleeved outside the drum 1, and the cooling device provided on the jacket 8 is used to take away the heat generated by the drum 1 to prevent energy accumulation.

[0073] In the separation method of the present invention, the separation efficiency of the drum 1 is 70%-95%.

[0074] In a specific embodiment of the present invention, a nitro - toluene / waste - acid mixture is injected from the inlet of the central tube 2 to the bottom of the drum 1. Then, the nitro - toluene / waste - acid mixture flows upward through the neutral holes 3 on the umbrella - shaped discs, and enters between adjacent umbrella - shaped discs respectively. The distance between adjacent umbrella - shaped discs is very small, so that the flowing - in nitro - toluene / waste - acid mixture is divided into many very thin liquid layers. Since the densities of nitro - toluene and waste acid contained in the nitro - toluene / waste - acid mixture are different, the centrifugal forces acting on nitro - toluene and waste acid in the drum 1 are also different. In the gap between the umbrella - shaped discs, the waste acid flows downward and outward through the openings on the orifice plate 5 along the lower surface of the umbrella - shaped disc. The nitro - toluene generates a centripetal buoyancy force due to the reaction force of the centrifugal force of the outer - layer waste acid. Under the action of the centripetal buoyancy force, the nitro - toluene flows upward and inward through the openings on the orifice plate 5 along the upper surface of the umbrella - shaped disc. Finally, the heavy - liquid waste acid accumulates in the heavy - liquid channel, and the waste acid is discharged from the heavy - liquid outlet 6 through the heavy - liquid channel. The nitro - toluene accumulates in the light - liquid channel, and the nitro - toluene is discharged from the light - liquid outlet 7 through the light - liquid channel, thereby achieving the purpose of separation. A jacket 8 is sleeved outside the drum 1, and a cooling device is arranged on the jacket 8. The cooling device is used to take away the heat generated by the drum 1 to prevent energy accumulation.

[0075] The present invention will be described in detail through examples below. The separation efficiency of the drum 1 is shown in Table 1.

[0076] The separation method of the nitro - toluene / waste - acid mixture in the following examples is as follows Figure 1It is carried out in the separation system of the nitro - toluene / waste acid mixture. This separation system includes a drum 1, a central tube 2, a disc stack 4, a heavy - liquid outlet 6, and a light - liquid outlet 7. The shape of the central tube 2 is cylindrical, and the diameter of the bottom surface of the cylinder is 10 - 100 mm. The disc stack is formed by equidistantly stacking multiple umbrella - shaped discs. The angle between the upper surface of the umbrella - shaped disc and the central tube 2 is 120°. Neutral holes 3 are provided on the umbrella - shaped discs, and orifice plates 5 are provided between adjacent umbrella - shaped discs. 5 - 10 orifice plates 5 are equidistantly arranged between adjacent umbrella - shaped discs. The orifice plates 5 are vertically arranged between adjacent umbrella - shaped discs, and the number of openings on the orifice plates 5 is 10 - 50. The number of umbrella - shaped discs in the disc stack 4 is 50 - 100. The distance between the two ends of the umbrella - shaped discs in the disc stack 4 is 100 mm, and the vertical distance between adjacent umbrella - shaped discs is 0.2 - 1.5 mm. The thickness of the umbrella - shaped disc is 0.1 - 0.5 mm. The neutral holes 3 are round holes, and the diameter of the neutral holes 3 is 100 - 300 mm. The space between the edge of the disc stack 4 far from the central tube 2 and the inner wall of the drum 1 forms a heavy - liquid channel, and the waste acid is discharged from the heavy - liquid outlet 6 through the heavy - liquid channel. The space between the edge of the disc stack 4 close to the central tube 2 and the outer wall of the central tube 2 forms a light - liquid channel, and the nitro - toluene is discharged from the light - liquid outlet 7 through the light - liquid channel. This separation system also includes a jacket 8, and the jacket 8 is sleeved outside the drum 1. A cooling device is provided on the jacket 8, and a cooling medium is filled in the cooling device.

[0077] Example 1

[0078] The inner diameter of the drum 1 is 178 mm, the rotation speed of the drum 1 is set to 2320 r / min, the centrifugal force of the drum 1 is 1510 kg, the shape of the central tube 2 is cylindrical, the diameter of the bottom surface of the cylinder is 80 mm, the diameter of the neutral hole 3 is 157 mm, the number of umbrella-shaped discs in the disc pack 4 is 80, the thickness of the umbrella-shaped disc is 0.35 mm, the distance between adjacent umbrella-shaped discs is 0.6 mm, 10 orifice plates 5 are arranged at equal distances between adjacent umbrella-shaped discs, the number of openings on the orifice plate 5 is 50 (the number of horizontal openings on the orifice plate 5 is 10, and the number of vertical openings on the orifice plate 5 is 5), the shape of the openings on the orifice plate 5 is an oval hole, the major axis of the oval hole is 0.05 mm, the minor axis of the oval hole is 0.04 mm, the diameter of the heavy liquid outlet 6 is 105 mm, the diameter of the light liquid outlet 7 is 85 mm, the jacket 8 is sleeved outside the drum 1, a cooling device is provided on the jacket 8, a cooling medium is filled in the cooling device, the cooling medium is a mixture of water, oil and salt, and the weight ratio of the amounts of water, oil and salt used is 1:0.7:1.5; the oil is polydimethylsiloxane, and the salt is sodium chloride;

[0079] Start the drum 1, inject a nitro toluene / waste acid mixture (the flow rate of the nitro toluene / waste acid mixture is 1000 L / h, and the volume ratio of nitro toluene to waste acid is 1:0.5) from the inlet of the central tube 2 to the bottom of the drum 1. Then, the nitro toluene / waste acid mixture flows upward through the neutral hole 3 on the umbrella-shaped disc and enters between adjacent umbrella-shaped discs respectively. In the gap between the umbrella-shaped discs, the waste acid flows downward and outward through the oval holes on the orifice plate 5 along the lower surface of the umbrella-shaped disc, and the nitro toluene flows upward and inward through the oval holes on the orifice plate 5 along the upper surface of the umbrella-shaped disc. Finally, the heavy liquid waste acid accumulates in the heavy liquid channel, and the waste acid is discharged from the heavy liquid outlet 6 through the heavy liquid channel. The nitro toluene accumulates in the light liquid channel and is discharged from the light liquid outlet 7 through the light liquid channel. The jacket 8 can take away the heat generated by the drum 1 to prevent energy accumulation; the separation efficiency of the drum 1 is 95%.

[0080] Example 2

[0081] The inner diameter of the drum 1 is 300 mm, the rotation speed of the drum 1 is set to 1600 r / min, the centrifugal force of the drum 1 is 2710 kg, the shape of the central tube 2 is cylindrical, the diameter of the bottom surface of the cylinder is 100 mm, the diameter of the neutral hole 3 is 292 mm, the number of umbrella-shaped discs in the disc group 4 is 50, the thickness of the umbrella-shaped disc is 0.5 mm, the distance between adjacent umbrella-shaped discs is 1 mm, 8 orifice plates 5 are arranged at equal distances between adjacent umbrella-shaped discs, the number of openings on the orifice plate 5 is 30 (the number of horizontal openings on the orifice plate 5 is 8, and the number of vertical openings on the orifice plate 5 is 5), the shape of the opening on the orifice plate 5 is a square hole, the side length of the square hole is 0.08 mm, the diameter of the heavy liquid outlet 6 is 150 mm, the diameter of the light liquid outlet 7 is 100 mm, the jacket 8 is sleeved outside the drum 1, a cooling device is arranged on the jacket 8, a cooling medium is filled in the cooling device, the cooling medium is a mixture of water, oil and salt, and the weight ratio of the amounts of water, oil and salt used is 1:0.8:1.6; the oil is polydimethylsiloxane, and the salt is sodium chloride;

[0082] Start the drum 1, inject a nitro toluene / waste acid mixture (the flow rate of the nitro toluene / waste acid mixture is 1000 L / h, and the volume ratio of nitro toluene to waste acid is 1:0.6) from the inlet of the central tube 2 to the bottom of the drum 1. Then, the nitro toluene / waste acid mixture flows upward through the neutral hole 3 on the umbrella-shaped disc and enters between adjacent umbrella-shaped discs respectively. In the gap between the umbrella-shaped discs, the waste acid flows downward and outward through the square holes on the orifice plate 5 along the lower surface of the umbrella-shaped disc, and the nitro toluene flows upward and inward through the square holes on the orifice plate 5 along the upper surface of the umbrella-shaped disc. Finally, the heavy liquid waste acid accumulates in the heavy liquid channel and the waste acid is discharged from the heavy liquid outlet 6 through the heavy liquid channel, and the nitro toluene accumulates in the light liquid channel and the nitro toluene is discharged from the light liquid outlet 7 through the light liquid channel. The jacket 8 can take away the heat generated by the drum 1 to prevent energy accumulation; the separation efficiency of the drum 1 is 85%.

[0083] Example 3

[0084] The inner diameter of the drum 1 is 295 mm, the rotation speed of the drum 1 is set to 3200 r / min, the centrifugal force of the drum 1 is 1710 kg, the shape of the central tube 2 is cylindrical, the diameter of the bottom surface of the cylinder is 35 mm, the diameter of the neutral hole 3 is 192 mm, the number of umbrella-shaped discs in the disc group 4 is 80, the thickness of the umbrella-shaped disc is 0.35 mm, the distance between adjacent umbrella-shaped discs is 0.4 mm, 6 orifice plates 5 are arranged at equal distances between adjacent umbrella-shaped discs, the number of openings on the orifice plate 5 is 30 (the number of horizontal openings on the orifice plate 5 is 6, and the number of vertical openings on the orifice plate 5 is 5), the shape of the openings on the orifice plate 5 is circular, the diameter of the circular hole is 0.05 mm, the diameter of the heavy liquid outlet 6 is 95 mm, the diameter of the light liquid outlet 7 is 75 mm, the jacket 8 is sleeved outside the drum 1, a cooling device is arranged on the jacket 8, a cooling medium is filled in the cooling device, the cooling medium is a mixture of water and salt, and the weight ratio of the usage amounts of water and salt is 1:1.6; the salt is sodium chloride;

[0085] Start the drum 1, inject a nitro toluene / waste acid mixture (the flow rate of the nitro toluene / waste acid mixture is 1000 L / h, and the volume ratio of nitro toluene to waste acid is 1:0.7) from the inlet of the central tube 2 to the bottom of the drum 1. Then, the nitro toluene / waste acid mixture flows upward through the neutral hole 3 on the umbrella-shaped disc and enters between adjacent umbrella-shaped discs respectively. In the gap between the umbrella-shaped discs, the waste acid flows downward and outward through the circular holes on the orifice plate 5 along the lower surface of the umbrella-shaped disc, and the nitro toluene flows upward and inward through the circular holes on the orifice plate 5 along the upper surface of the umbrella-shaped disc. Finally, the heavy liquid waste acid accumulates in the heavy liquid channel and the waste acid is discharged from the heavy liquid outlet 6 through the heavy liquid channel, and the nitro toluene accumulates in the light liquid channel and the nitro toluene is discharged from the light liquid outlet 7 through the light liquid channel. The jacket 8 can take away the heat generated by the drum 1 to prevent energy accumulation; the separation efficiency of the drum 1 is 70%.

[0086] Example 4

[0087] According to the method of Example 1, the difference is that in Example 4, the cooling medium of the cooling device is water. The waste acid is discharged from the heavy liquid outlet 6 through the heavy liquid channel, and the nitro toluene accumulates in the light liquid channel and the nitro toluene is discharged from the light liquid outlet 7 through the light liquid channel; the separation efficiency of the drum 1 is 75%.

[0088] Example 5

[0089] According to the method of Example 1, the difference is that in Example 5, 8 of the orifice plates 5 are arranged at equal distances between adjacent umbrella-shaped discs, the number of openings on the orifice plate 5 is 30 (the number of horizontal openings on the orifice plate 5 is 6, and the number of vertical openings on the orifice plate 5 is 5), the shape of the openings on the orifice plate 5 is an elliptical hole, the major axis of the elliptical hole is 0.05 mm, and the minor axis of the elliptical hole is 0.04 mm; waste acid is discharged from the heavy liquid outlet 6 through the heavy liquid channel, nitrotoluene accumulates in the light liquid channel, and nitrotoluene is discharged from the light liquid outlet 7 through the light liquid channel; the separation efficiency of the rotating drum 1 is 70%.

[0090] Example 6

[0091] According to the method of Example 1, the difference is that in Example 6, the distance between adjacent umbrella-shaped discs is 1.8 mm, waste acid is discharged from the heavy liquid outlet 6 through the heavy liquid channel, nitrotoluene accumulates in the light liquid channel, and nitrotoluene is discharged from the light liquid outlet 7 through the light liquid channel; the separation efficiency of the rotating drum 1 is 70%.

[0092] Example 7

[0093] According to the method of Example 1, the difference is that in Example 7, the number of umbrella-shaped discs in the disc group 4 is 60, waste acid A7 is discharged from the heavy liquid outlet 6 through the heavy liquid channel, nitrotoluene accumulates in the light liquid channel, and nitrotoluene B7 is discharged from the light liquid outlet 7 through the light liquid channel; the separation efficiency of the rotating drum 1 is 75%.

[0094] Example 8

[0095] According to the method of Example 2, the difference is that the side length of the square hole is 0.05 mm, waste acid is discharged from the heavy liquid outlet 6 through the heavy liquid channel, nitrotoluene accumulates in the light liquid channel, and nitrotoluene is discharged from the light liquid outlet 7 through the light liquid channel; the separation efficiency of the rotating drum 1 is 88%.

[0096] Example 9

[0097] According to the method of Example 2, the difference is that the rotation speed of the rotating drum 1 is set to 1500 r / min, waste acid is discharged from the heavy liquid outlet 6 through the heavy liquid channel, nitrotoluene accumulates in the light liquid channel, and nitrotoluene is discharged from the light liquid outlet 7 through the light liquid channel; the separation efficiency of the rotating drum 1 is 70%.

[0098] Example 10

[0099] According to the method of Example 2, except that the rotation speed of the drum 1 is set to 3300 r / min, waste acid is discharged from the heavy liquid outlet 6 through the heavy liquid channel, nitro toluene accumulates in the light liquid channel, and nitro toluene is discharged from the light liquid outlet 7 through the light liquid channel; the separation efficiency of the drum 1 is 85%.

[0100] Comparative Example 1

[0101] According to the method of Example 1, except that in Comparative Example 1, the orifice plate 5 is not provided between adjacent umbrella-shaped discs. Waste acid flows downward and outward along the lower surface of the umbrella-shaped discs, and nitro toluene flows upward and inward along the upper surface of the umbrella-shaped discs. Finally, heavy liquid waste acid accumulates in the heavy liquid channel, and waste acid is discharged from the heavy liquid outlet 6 through the heavy liquid channel. Nitro toluene accumulates in the light liquid channel, and nitro toluene is discharged from the light liquid outlet 7 through the light liquid channel; the separation efficiency of the drum 1 is 35%.

[0102] Comparative Example 2

[0103] According to the method of Example 2, except that in Comparative Example 2, the side length of the square hole is 0.09 mm, and the separation efficiency of the drum 1 is 60%.

[0104] Comparative Example 3

[0105] According to the method of Example 3, except that in Comparative Example 3, the number of openings on the orifice plate 5 is 9 (the number of horizontal openings on the orifice plate 5 is 3, and the number of vertical openings on the orifice plate 5 is 3); the separation efficiency of the drum 1 is 50%.

[0106] Test Example 1

[0107] The total discharge amount is obtained by adding the discharged waste acid and the discharged nitro toluene, and the separation efficiency is obtained by dividing the total discharge amount by the injection amount of the nitro toluene / waste acid mixture injected into the bottom of the drum 1.

[0108] The separation efficiencies of the drum 1 in Examples 1-10 and Comparative Examples 1-3 were calculated, and the results are shown in Table 1 below.

[0109] Test Separation efficiency Example 1 95％ Example 2 85％ Example 3 70％ Example 4 75％ Example 5 70％ Example 6 70％ Example 7 75％ Example 8 88％ Example 9 70％ Example 10 85％ Comparative Example 1 35％ Comparative Example 2 60％ Comparative Example 3 50％

[0110] It can be seen from the results in Table 1 that in the separation system of the present invention, an orifice plate is provided between adjacent umbrella-shaped discs, and the number of openings on the orifice plate, the distance between adjacent umbrella-shaped discs, the number of umbrella-shaped discs, the rotation speed of the drum, etc. are all key parameters affecting the separation efficiency. When these key parameters are set within a reasonable range, the problem of difficult to balance flame quenching and separation efficiency can be solved.

[0111] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of technical features. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A separation system for a nitro-toluene / waste acid mixture, characterized in that, The separation system includes a drum (1), a central tube (2), a disc stack (4), a heavy liquid outlet (6), and a light liquid outlet (7); the disc stack (4) is formed by equidistantly stacking a plurality of umbrella-shaped discs, and neutral holes (3) are provided on the umbrella-shaped discs; a heavy liquid channel is formed between the edge of the disc stack (4) far from the central tube (2) and the inner wall of the drum (1) for discharging waste acid; a light liquid channel is formed between the edge of the disc stack (4) close to the central tube (2) and the outer wall of the central tube (2) for discharging nitrotoluene. An orifice plate (5) is provided between adjacent umbrella-shaped discs. The number of openings on the orifice plate (5) is 10 - 50, and the diameter of the openings is 0.01 - 0.08 mm.

2. The separation system for the nitro-toluene / waste acid mixture according to claim 1, wherein The number of orifice plates (5) equidistantly arranged between adjacent umbrella-shaped discs is 5 - 10.

3. The separation system for the nitro-toluene / waste acid mixture according to claim 1 or 2, characterized in that, The number of horizontal openings on the orifice plate (5) is 5 - 10, and the number of vertical openings on the orifice plate (5) is 2 - 5.

4. The separation system for nitro-toluene / waste acid mixture according to claim 3, characterized in that, The shape of the openings on the orifice plate (5) is a round hole, an oval hole, or a square hole.

5. The separation system for the nitro-toluene / waste acid mixture according to claim 1, characterized in that, The number of umbrella-shaped discs in the disc stack (4) is 50 - 100.

6. The separation system for nitro - toluene / waste acid mixture according to claim 1 or 5, characterized in that, The vertical distance between adjacent umbrella-shaped discs is 0.1 - 1 mm.

7. The separation system for nitro-toluene / waste acid mixture according to claim 1 or 5, characterized in that, The thickness of the umbrella-shaped disc is 0.1 - 0.5 mm.

8. The separation system for the nitro - toluene / waste acid mixture according to claim 1, characterized in that, The neutral hole (3) is a round hole, and the diameter of the neutral hole (3) is 100 - 300 mm.

9. The separation system for nitro-toluene / waste acid mixture according to claim 1, characterized in that The separation system further includes a jacket (8) sleeved outside the drum (1).

10. The separation system for the nitro-toluene / waste acid mixture according to claim 9, characterized in that, A cooling device is provided on the jacket (8) for cooling the drum (1).

11. A method for separating a nitro - toluene / waste acid mixture, characterized in that, The separation method is implemented in the separation system for nitrotoluene / waste acid mixture according to any one of claims 1 - 10, and is characterized in that the separation method includes the following steps: (1) Inject the nitrotoluene / waste acid mixture from the inlet of the central tube (2) to the bottom of the drum (1). The nitrotoluene / waste acid mixture flows upward through the neutral holes (3) and enters the space between adjacent umbrella-shaped discs. (2) The waste acid passes through the orifice plate (5) along the lower surface of the umbrella-shaped disc and enters the heavy liquid gap, and is discharged from the heavy liquid outlet (6); the nitrotoluene passes through the orifice plate (5) along the upper surface of the umbrella-shaped disc and enters the light liquid gap, and is discharged from the light liquid outlet (7).

12. The separation method of the nitro toluene / waste acid mixture according to claim 11, characterized in that, The rotational speed of the drum (1) is 1600 - 3200 r / min.

13. The separation method of the nitro-toluene / waste acid mixture according to claim 11, characterized in that, The nitrotoluene / waste acid mixture contains nitrotoluene and waste acid, and the volume ratio of nitrotoluene to waste acid is 1:(0.5 - 0.7).

14. The separation method of the nitro-toluene / waste acid mixture according to claim 11, characterized in that, The flow rate of the nitrotoluene / waste acid mixture is 100 - 1000 L / h.

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