Preheating type evaporator with adjustable collision air volume

Abstract

The utility model relates to the technical field of evaporators, in particular to a pre-heating type evaporator with adjustable collision air quantity, which comprises a barrel body consisting of a small-barrel-diameter upper barrel body and a large-barrel-diameter lower barrel body, and the upper end and the lower end of the barrel body are respectively communicated with a gas production outlet and a liquid discharge port; a demister, a heating coil pipe, a spraying pipe, an adjusting mechanism, an anti-explosion electric heater, a heating tube nest and an exhaust disc are arranged in the cylinder body; the adjusting mechanism comprises a plurality of turning plates which are arranged in a staggered lap joint mode, extending arms are arranged on turning plate rotating shafts, the tail ends of the extending arms are provided with hinge arms, the turning plate rotating shafts in the center extend and are provided with sealing seats containing limiting plates, limiting hole sets are formed in the limiting plates in a penetrating mode, rotating rods are fixed to the turning plate rotating shafts in the center, and positioning pins connected with the limiting hole sets in an inserted mode are arranged on the rotating rods. The preheating type evaporator with the adjustable impact air volume is high in methanol vaporization efficiency, good in mixing efficiency and uniform in concentration of produced formaldehyde.

Description

Technical Field

[0001] This utility model relates to the field of evaporator technology, specifically to a preheating evaporator with adjustable airflow. Background Technology

[0002] An evaporator is a device that uses heat energy to cause a partial or complete phase change in a liquid, producing a gaseous phase. The main functions of an evaporator include concentrating solutions, separating components, and generating products.

[0003] Currently, the process principle for producing formaldehyde by methanol oxidation is as follows: liquid methanol is vaporized in an evaporator and mixed with oxygen in the air. Under the catalytic action of the process temperature and catalyst, formaldehyde is generated through oxidative dehydrogenation. In this process, preheated air is used as a carrier and heat source to convert liquid methanol into gaseous methanol and mix them.

[0004] However, conventional evaporators still have the following shortcomings in the process of methanol oxidation to formaldehyde:

[0005] Air is preheated by an external heat exchanger and then sent into the evaporator to contact the sprayed methanol solution, thereby vaporizing and mixing the methanol. As a result, the vaporization efficiency of methanol is low, and in the continuous production process, the formaldehyde concentration produced is uneven. Utility Model Content

[0006] To address the technical problems existing in the background art, this utility model provides a preheating evaporator with adjustable air volume, which has high methanol vaporization efficiency and high mixing efficiency, ensuring uniform formaldehyde concentration in the output.

[0007] The technical solution adopted by this utility model is:

[0008] An adjustable airflow preheating evaporator includes: a cylinder body, which is composed of an upper cylinder body and a lower cylinder body connected in series; the upper cylinder body has an outlet gas port connected to the center of its upper end, and the lower cylinder body has a drain gas port connected to the center of its lower end; the diameter of the upper cylinder body is smaller than the diameter of the lower cylinder body; a demister, a heating coil, and a spray pipe are arranged sequentially from top to bottom inside the upper cylinder body; an adjusting mechanism, an explosion-proof electric heater, a heating tube, and an exhaust plate are arranged sequentially from top to bottom inside the lower cylinder body.

[0009] The adjustment mechanism includes:

[0010] A mounting base is fixed to the inner wall of the lower cylinder. A flap is hinged inside the mounting base. A groove is provided on the surface of the flap. An extension arm extends radially along the flap's rotating shaft. A hinge arm is hinged at the end of the extension arm. The extension arm and the hinge arm are housed in the groove. A central flap rotating shaft extends and is coaxially provided with a sealing seat that is sealed to the lower cylinder. A limit plate is provided on the outer wall of the sealing seat. A limit hole group is provided through the limit plate. A rotating rod extending radially is coaxially fixed on the central flap rotating shaft. A positioning pin is provided on the rotating rod that is inserted into the limit hole group.

[0011] Furthermore, the heating coil is configured as a spiral with the inlet in the center and the outlet on the periphery, and a fan is connected to the inlet pipe of the heating coil.

[0012] The spray pipe is configured as a branch pipe, and a spray pump is connected to the inlet pipe of the spray pipe.

[0013] Furthermore, a support ear is fixedly provided on the inner wall of the upper cylinder. The support ear is arranged in three layers from top to bottom, and is used to fix the demister, heating coil and spray pipe respectively.

[0014] Furthermore, the mounting base is configured as an annular shape, and a notch is provided on one side of the annular mounting base.

[0015] The flaps are arranged in a staggered manner with multiple flaps in parallel. The axes of the multiple flaps are set on the same inclined surface, and the flap axes are inclined downward at the notch of the mounting base.

[0016] Furthermore, the sealing seat is configured as a flange.

[0017] The limiting plate extends radially along the sealing seat and is configured in a fan shape.

[0018] The limiting holes of the limiting hole group are arranged in a circular array around the axis of the sealing seat.

[0019] The positioning pin is designed to be telescopic.

[0020] Furthermore, the exhaust pipe of the exhaust disc extends to the lower cylinder body and is connected to the heating coil outlet.

[0021] Furthermore, a liquid level tank is connected to the outer wall of the lower cylinder on one side of the exhaust plate, and a liquid level gauge, a reflux material port, and an overflow material port are connected to the liquid level tank.

[0022] The level gauge is used to monitor the liquid level of the solution inside the lower cylinder.

[0023] The reflux material inlet and overflow material inlet are used to replenish and discharge the solution in the lower cylinder, respectively.

[0024] Furthermore, a circulating pump is connected to the drain port of the lower cylinder, and a storage tank and a heat exchanger are connected to the outlet of the circulating pump. The storage tank is connected to the material storage tank and the inlet of the spray pump, and the heat exchanger is connected to the waste liquid storage tank.

[0025] Furthermore, a mixer is connected to the inlet of the spray pump, and a filter is connected to the main inlet of the mixer. The filter is connected to the outside air, and the side inlet of the mixer is connected to the storage tank.

[0026] The beneficial effects of this utility model of a preheating evaporator with adjustable airflow are as follows:

[0027] 1. The outside air is preheated once by the heat exchanger, and then the preheated air is preheated a second time by the heating coil. The air that has been preheated twice is discharged through the exhaust plate immersed in the solution, which accelerates the vaporization of the solution in the lower cylinder and speeds up the mixing of gaseous methanol and air.

[0028] 2. By adjusting the air intake and the angle of the flap, the collision air volume of the sprayed solution and mixed gas is changed; by adjusting the output gas discharge volume, the uniformity of the output gas concentration is ensured. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the process flow of an example of this utility model;

[0030] Figure 2 This is a three-dimensional schematic diagram of the interior of the upper cylinder of this utility model embodiment;

[0031] Figure 3 This is a three-dimensional schematic diagram of the adjustment mechanism of this utility model. Figure 1 ;

[0032] Figure 4 This is a three-dimensional schematic diagram of the adjustment mechanism of this utility model. Figure 2 ;

[0033] Figure 5 This is a three-dimensional schematic diagram of the interior of the lower cylinder of this utility model.

[0034] In the picture:

[0035] 10. Upper cylinder; 11. Demister; 12. Heating coil; 13. Spray pipe; 14. Fan; 15. Spray pump.

[0036] 16. Supporting ear,

[0037] 20. Lower cylinder; 21. Adjustment mechanism; 22. Explosion-proof electric heater; 23. Heating tubes; 24. Liquid level tank.

[0038] 25. Exhaust disc, 26. Circulation pump, 27. Heat exchanger.

[0039] 210. Mounting base; 211. Flip plate; 212. Receiving groove; 213. Extension arm; 214. Hinge arm; 215. Sealing seat.

[0040] 216. Limiting plate; 217. Limiting hole assembly; 218. Rotating rod; 219. Positioning pin.

[0041] 30. Storage tank; 31. Mixer; 32. Filter. Detailed Implementation

[0042] To more clearly and explicitly illustrate the specific implementation objectives and methods of this utility model, the technical solution of this utility model will be fully described below. The described embodiments are only some embodiments of this utility model, not all embodiments. Without creative effort, all other embodiments based on the described embodiments of this utility model are within the protection scope of this utility model.

[0043] This utility model discloses a preheating evaporator with adjustable airflow, such as... Figure 1 As shown, it includes:

[0044] The upper cylinder 10 and the lower cylinder 20 are connected from top to bottom, and the diameter of the upper cylinder 10 is smaller than the diameter of the lower cylinder 20.

[0045] An outlet is connected to the center of the upper cylinder 10. Inside the upper cylinder 10, from top to bottom, a demister 11, a heating coil 12, and a spray pipe 13 are arranged in a spiral shape with the inlet in the center and the outlet on the periphery. The inlet and outlet pipes of the heating coil 12 extend to the outside of the upper cylinder 10. A fan 14 is connected to the inlet pipe of the heating coil 12 extending to the outside of the upper cylinder 10. The spray pipe 13 is a branch pipe. The inlet pipe of the spray pipe 13 extends to the outside of the upper cylinder 10 and is connected to a spray pump 15. Support ears 16 are fixedly installed on the inner wall of the upper cylinder 10. The support ears 16 are arranged in three layers from top to bottom and are used to fix the demister 11, the heating coil 12, and the spray pipe 13 respectively.

[0046] The lower cylinder 20 is provided with an adjustment mechanism 21, an explosion-proof electric heater 22, a heating tube 23, and an exhaust plate 25 arranged from top to bottom.

[0047] Adjustment mechanism 21 includes:

[0048] A mounting base 210 is fixedly connected to the inner wall of the lower cylinder 20. The mounting base 210 is annular, with a notch on one side. A flap 211 is hinged inside the ring of the mounting base 210. Multiple flaps 211 are arranged side by side in an overlapping manner, with their axes coplanar. The axes of the multiple flaps 211 face downwards towards the notch of the mounting base 210. A receiving groove 212 is provided on the surface of the flap 211. An extension arm 213 extends radially along the rotating shaft of the flap 211. A hinged arm 214 is hinged at the end of the extension arm 213. The extension arm 213 and the hinged arm 214 are accommodated in the receiving groove 212. The rotating shaft of the central flap 211 extends to the outside of the lower cylinder 20 and is connected to the... The shaft is provided with a sealing seat 215 that is sealed to the lower cylinder 20. The sealing seat 215 is in the form of a flange and is sealed and fixedly connected to the flange on the outer wall of the lower cylinder 20. A limiting plate 216 extending radially is coaxially provided on the outer wall of the sealing seat 215. The limiting plate 216 is fan-shaped and has a limiting hole group 217 through it. The limiting holes of the limiting hole group 217 are arranged in a circular array around the axis of the sealing seat 215. The central flap 211 extends to the outer end of the sealing seat 215 and is coaxially fixed with a rotating rod 218 extending radially along the central flap 211. The rotating rod 218 is provided with a positioning pin 219 that is inserted into the limiting hole group 217. The positioning pin 219 is telescopic.

[0049] The explosion-proof electric heater 22 is located directly below the flap 211, and the heating tube of the explosion-proof electric heater 22 is arranged parallel to the rotating shaft of the flap 211.

[0050] The tube side of the heating tube 23 is connected to the lower cylinder 20, and the shell side of the heating tube 23 is connected to the steam pipeline and the condensate circuit. The catalyst is placed at the upper end of the heating tube 23.

[0051] An exhaust port is connected to the upper end of the exhaust plate 25, and multiple exhaust ports are arranged in a rectangular array. An exhaust pipe is connected to one side of the exhaust plate 25, extending to the outside of the lower cylinder 20 and connecting to the exhaust port pipe of the heating coil 12.

[0052] A liquid level tank 24 is connected to the outer wall of the lower cylinder 20 on one side of the exhaust plate 25. A liquid level gauge, a return material port, and an overflow material port are connected to the liquid level tank 24.

[0053] A drain outlet is connected to the center of the lower end of the lower cylinder 20. A circulation pump 26 is connected to the drain outlet pipe. A storage tank 30 and a heat exchanger 27 are connected to the outlet of the circulation pump 26 via a three-way fitting. A solution inlet, a liquid outlet, and a gas outlet are connected to the storage tank 30. The solution inlet pipe is connected to the material storage tank via a transfer pump. The liquid outlet pipe is connected to the inlet pipe of the spray pump 15. A mixer 31 is connected to the gas outlet pipe. The main inlet of the mixer 31 is connected to the outside air via a filter 32. The main outlet of the mixer 31 is connected to the inlet of the fan 14. The liquid outlet pipe is connected to the inlet of the spray pump 15. The heat exchanger 27 is used to cool the drained liquid and recover waste heat, and to preheat the outside air at the inlet of the filter 32.

[0054] Based on the specific structure of the preheating evaporator with adjustable airflow in the above embodiments, the process flow for the methanol oxidation to formaldehyde is further explained below:

[0055] A. Methanol solution circulation:

[0056] The methanol solution enters the storage tank 30 through the solution inlet. The methanol solution in the storage tank 30 is supplied to the spray pipe 13 by the spray pump 15 and sprayed into the upper cylinder 10 until it enters the lower cylinder 20.

[0057] The methanol solution in the lower cylinder 20 passes through the regulating mechanism 21, the explosion-proof electric heater 22, and the heating tube 23 in sequence until it reaches the bottom of the lower cylinder 20 and submerges the exhaust plate 25.

[0058] The level of methanol solution in the lower cylinder 20 is monitored by a level gauge to ensure that the venting plate 25 is submerged. The overflow port is connected to the methanol solution storage tank. When the level of methanol solution in the lower cylinder 20 is higher than the upper limit, excess methanol solution is discharged through the overflow port. The return port is connected to the methanol solution storage tank or storage tank 30. When the level of methanol solution in the lower cylinder 20 is lower than the lower limit, methanol solution is replenished through the return port.

[0059] The methanol solution at the bottom of the lower cylinder 20 is sequentially transported back to the storage tank 30 through the drain port of the lower cylinder 20 and the circulation pump 26, or transported to the dilute alcohol waste liquid storage tank through the heat exchanger 27.

[0060] B. Evaporation process:

[0061] The outside air is preheated once by the waste heat recovered by the heat exchanger 27. After the first preheating, the outside air passes through the filter 32, mixer 31, and fan 14 in sequence to the heating coil 12 for a second preheating. It is then supplied to the exhaust plate 25 and discharged from the exhaust port on the exhaust plate 25, which accelerates the vaporization of methanol and fully mixes it with oxygen in the air.

[0062] The mixture of methanol and oxygen is heated to the process temperature by heating tube 23 and explosion-proof electric heater 22, and oxidized into formaldehyde gas, which is then discharged from the outlet of the upper cylinder 10.

[0063] C. Adjustment of airflow volume:

[0064] Pull out the positioning pin 219 inside the limiting hole group 217, rotate the rotating rod 218 to make the central flap 211 rotating shaft rotate, which drives the extension arm 213 on the central flap 211 rotating shaft to rotate, thereby causing the hinge arm 214 to rotate and move, which drives the extension arms 213 on the flap 211 rotating shafts on both sides of the central flap 211 on the hinge arm 214 to rotate, that is, the central flap 211 and the flaps 211 on both sides rotate synchronously; adjust the angle of the flap 211 according to the insertion position of the positioning pin 219 and the limiting hole group 217, thereby changing the air volume;

[0065] When the flap 211 is in a closed state, the methanol solution is sprayed from the spray pipe 13 onto the inclined flap 211 and flows down through the notch of the mounting base 210; when the flap 211 is in a semi-closed state, the methanol solution is sprayed from the spray pipe 13 and flows down through the gap between the multiple flaps 211.

[0066] When the concentration of formaldehyde gas produced is too low, adjust the opening of the regulating valve at the gas outlet of the upper cylinder 10, maintain the circulation of methanol solution, keep the flap 211 in a closed or semi-closed state, and adjust the opening of the regulating valve on the external air supply pipeline to prolong the phase change time and mixing time of methanol solution and methanol gas mixed with oxygen in the lower cylinder 20, reduce the amount of external air entering, and thus increase the concentration of formaldehyde gas produced.

[0067] In summary, the above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of this utility model. Based on the above description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification. All equivalent variations and modifications of the shape, structure, features, and spirit described in the claims of this utility model should be included within the scope of the claims of this utility model.

Claims

1. A preheating evaporator with adjustable airflow, comprising: A cylindrical body, comprising an upper cylindrical body (10) and a lower cylindrical body (20) connected in series, wherein an outlet for gas production is connected to the center of the upper end of the upper cylindrical body (10), and a drain outlet for liquid is connected to the center of the lower end of the lower cylindrical body (20), characterized in that: The diameter of the upper cylinder (10) is smaller than the diameter of the lower cylinder (20); Inside the upper cylinder (10), from top to bottom, are arranged a demister (11), a heating coil (12), and a spray pipe (13). The lower cylinder (20) is provided with an adjustment mechanism (21), an explosion-proof electric heater (22), a heating tube (23), and an exhaust plate (25) arranged from top to bottom. The adjustment mechanism (21) includes: A mounting base (210) is fixed to the inner wall of the lower cylinder (20). A flap (211) is hinged inside the mounting base (210). A groove (212) is provided on the surface of the flap (211). An extension arm (213) is provided radially along the rotating shaft of the flap (211). A hinge arm (214) is hinged at the end of the extension arm (213). The extension arm (213) and the hinge arm (214) are accommodated in the groove (212). The flap (211) in the center is... 1) A rotating shaft is extended and a sealing seat (215) is coaxially provided to seal and connect with the lower cylinder (20). A limiting plate (216) is provided on the outer wall of the sealing seat (215). A limiting hole group (217) is provided through the limiting plate (216). A rotating rod (218) extending radially is coaxially fixed on the rotating shaft of the central flap (211). A positioning pin (219) is provided on the rotating rod (218) to be inserted into the limiting hole group (217).

2. The preheating evaporator with adjustable airflow according to claim 1, characterized in that: The heating coil (12) is configured as a spiral with the inlet in the center and the outlet on the periphery, and a fan (14) is connected to the inlet pipe of the heating coil (12). The spray pipe (13) is configured as a branch pipe, and a spray pump (15) is connected to the inlet pipe of the spray pipe (13).

3. A preheating evaporator with adjustable airflow according to claim 1, characterized in that: The upper cylinder (10) is fixedly provided with a support ear (16) on the inner wall. The support ear (16) has three layers from top to bottom, which are used to fix the demister (11), heating coil (12) and spray pipe (13) respectively.

4. A preheating evaporator with adjustable airflow according to claim 2, characterized in that: The mounting base (210) is configured as an annular shape, and a notch is provided on one side of the annular mounting base (210); The flaps (211) are arranged in a staggered manner with multiple flaps (211) in parallel. The axes of the multiple flaps (211) are arranged on the same inclined surface, and the axis of the flaps (211) is inclined downward at the notch of the mounting base (210).

5. A preheating evaporator with adjustable airflow according to claim 4, characterized in that: The sealing seat (215) is configured as a flange. The limiting plate (216) extends radially along the sealing seat (215), and the limiting plate (216) is configured as a fan shape; The limiting hole group (217) has multiple limiting holes arranged in a circular array around the axis of the sealing seat (215); The positioning pin (219) is configured to be telescopic.

6. A preheating evaporator with adjustable airflow according to claim 4, characterized in that: The exhaust pipe of the exhaust plate (25) extends to the outside of the lower cylinder (20) and is connected to the outlet of the heating coil (12).

7. A preheating evaporator with adjustable airflow according to claim 6, characterized in that: A liquid level tank (24) is connected to the outer wall of the lower cylinder (20) on one side of the exhaust plate (25), and a liquid level gauge, a return material port and an overflow material port are connected to the liquid level tank (24). The level gauge is used to monitor the liquid level of the solution inside the lower cylinder (20); The reflux material port and overflow material port are used to replenish and discharge the solution in the lower cylinder (20), respectively.

8. A preheating evaporator with adjustable airflow according to claim 6, characterized in that: The lower cylinder (20) is connected to a circulation pump (26) at its drain port. The outlet of the circulation pump (26) is connected to a storage tank (30) and a heat exchanger (27). The storage tank (30) is connected to a material storage tank and the inlet of a spray pump (15). The heat exchanger (27) is connected to a waste liquid storage tank.

9. A preheating evaporator with adjustable airflow according to claim 8, characterized in that: The spray pump (15) is connected to a mixer (31) at its inlet. The main inlet of the mixer (31) is connected to a filter (32). The filter (32) is connected to the outside air. The side inlet of the mixer (31) is connected to the storage tank (30).

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