An evaporation separator, a method and a urea production device using the same

Abstract

The present invention belongs to an evaporation separator, a method and a urea production device using the same; it includes a separator housing, the separator housing is provided with a volute-type urea solution inlet pipe, the volute-type urea solution inlet pipe is communicated with the urea solution inlet, the bottom of the separator housing is provided with a urea solution outlet, the top of the separator housing is provided with a gas phase outlet, a separation cylinder is arranged inside the separator housing, the upper part of the separation cylinder is connected to the inner wall of the separator housing, and the lower part of the separation cylinder is a gas phase inlet communicated with the gas phase outlet; a gas phase acceleration cylinder is arranged between the separation cylinder and the gas phase outlet, a steam coil is arranged between the gas phase acceleration cylinder and the separation cylinder, a spray head is arranged at the lower part of the steam coil, and the position corresponding to the lower part of the spray head is the inner wall of the lower part of the separation cylinder; it has the advantages of simple structure, reasonable design, no need to use a flushing water pipe, stable operation, reduced investment cost, avoidance of condensate generation, and effectively reducing the influence of condensate on the main system during urea production.

Description

Technical Field

[0001] The present invention belongs to the technical field of urea production, and particularly relates to an evaporation separator, a method, and a urea production device using the same. Background Art

[0002] In the process of urea production, taking advantage of the characteristic that urea solution has two boiling points during evaporation, generally, whether it is the aqueous solution full recycle method, the carbon dioxide stripping method, or the ammonia stripping process, the final evaporation of urea solution basically selects the method of using secondary evaporation to concentrate the urea solution, that is, the so-called primary evaporation heater and secondary evaporation heater. Condensate is an inevitable product in the urea production process, usually determined by side reactions of urea; after the condensate is generated, it usually falls off under the action of flushing water and then enters the final granulation system along with the urea solution. Under normal circumstances, the condensate has little impact on the system, but larger condensates will cause a rapid change in urea flow rate, and in severe cases, it will cause the device to stop. Currently, the solutions to this problem mainly focus on the transformation of the separator and the addition of new auxiliary equipment; for example: integrating the heater and the separation device directly into one, and the liquid flowing out of the separator does not flow out from the bottom but from the side, which avoids the impact of the falling off of the condensate on the stable production of the system, but the condensate still remains in the system; another example is to add a mist eliminator to separate urea in the gas phase, reduce the height of the shell, and increase a negative pressure air suction device to reduce the residence time of the gas phase in the shell; the above methods are not only complex in structure, but also cannot ensure that no condensate is generated in the evaporation separator, and can only reduce the generation amount of condensate, and cannot fundamentally solve the problem of condensate generation; specifically, adding a mist eliminator to separate urea in the gas phase can reduce the content of urea in the gas phase, but cannot eliminate it, so the amount of condensate generated will decrease, but it will still be generated; reducing the height of the shell and increasing a negative pressure air suction device, but there will inevitably be blind spots in the shell. In addition, the evaporation separator itself is in a negative pressure state during operation, and adding a new negative pressure device cannot achieve an ideal gas flow rate under the influence of the shell's own structure; therefore, the generation of condensate cannot be avoided. Summary of the Invention

[0003] The purpose of the present invention is to overcome the defects in the prior art, and provide an evaporation separator, a method, and a urea production device using the same, which have a simple structure, reasonable design, do not require the use of a flushing water pipe, operate stably, and can eliminate the generation of condensate without adding large-scale equipment.

[0004] The purpose of the present invention is achieved as follows:

[0005] An evaporation separator, which includes a separator housing. There is a volute-shaped urea solution inlet pipe in the middle of the separator housing. The volute-shaped urea solution inlet pipe is connected to the urea solution inlet provided on the separator housing. The bottom of the separator housing is provided with a urea solution outlet, and the top of the separator housing is provided with a gas phase outlet. Inside the separator housing, there is a separation cylinder with a funnel-shaped structure. The upper part of the separation cylinder is connected to the inner wall of the separator housing, and the lower part of the separation cylinder is a gas phase inlet connected to the gas phase outlet. A gas phase acceleration cylinder is provided between the separation cylinder and the gas phase outlet. A steam coil is provided at the connection between the gas phase acceleration cylinder and the separation cylinder. A nozzle is provided below the steam coil, and the position corresponding to the lower part of the nozzle is the inner wall of the lower part of the separation cylinder.

[0006] Further, the steam coil is connected to a steam pipe network provided outside the separator housing through a steam pipe.

[0007] Further, the cross-section of the gas phase acceleration cylinder is one of a rectangle or a trapezoid with a smaller upper part and a larger lower part.

[0008] Further, the upper part of the gas phase acceleration cylinder is connected to the inner wall of the gas phase outlet.

[0009] Further, the lower part of the gas phase acceleration cylinder is connected to the top of the steam coil.

[0010] Further, there is a gap between the steam coil and the separation cylinder.

[0011] A method for an evaporation separator, which includes the following steps:

[0012] Step 1: The steam in the steam pipe network enters the steam coil through the steam pipe, and blows the inner wall of the lower part of the separation cylinder through the nozzle.

[0013] Step 2: While the nozzle blows steam in Step 1, the urea solution enters the separator housing through the volute-shaped urea solution inlet pipe and the urea solution inlet for gas-liquid separation. The liquid phase enters the next process section through the urea solution outlet.

[0014] Step 3: The gas phase separated in Step 2 is discharged into the next process section through the gas phase inlet at the lower part of the separation cylinder, the gas phase acceleration cylinder, and the gas phase outlet.

[0015] Step 4: When the gas phase in Step 3 passes through the inner wall of the lower part of the separation cylinder, due to continuous blowing of steam, the gas phase cannot stay on the inner wall of the lower part of the separation cylinder and cannot form condensates.

[0016] Step 5: When the gas phase in Step 3 passes through the gap, due to the continuous injection of steam, the gas phase cannot enter the space between the separator housing and the gas phase acceleration cylinder, and no condensate can be formed.

[0017] Step 6: When the gas phase in Step 3 passes through the gas phase acceleration cylinder, the gas phase is mixed with steam and the space in the gas phase acceleration cylinder is small. Under the dual action, the gas phase can quickly pass through the gas phase acceleration cylinder, preventing the gas phase from staying on the inner wall of the gas phase acceleration cylinder and thus no condensate can be formed.

[0018] Step 7: During operation, the inside of the separator housing is in a negative pressure state, and the setting of the gap can make the pressure inside the separator housing the same.

[0019] Preferably, in Step 1, the steam pressure in the steam pipeline network is 0.3 - 0.5 MPa, and the temperature is 140 - 160 °C.

[0020] Preferably, in Step 3, the flow rate of the gas phase passing through the gas phase inlet at the lower part of the separation cylinder, the gas phase acceleration cylinder, and the gas phase outlet is not less than 7 m / s.

[0021] The present invention also provides a urea production device, including a first-stage evaporation heater and a second-stage evaporation heater, and both the first-stage evaporation heater and the second-stage evaporation heater are the above-mentioned evaporation separators.

[0022] The present invention has the advantages of simple structure, reasonable design, no need to use a flushing water pipe, stable operation, reduced investment cost, avoidance of condensate formation, and effectively reducing the impact of condensate on the main system during urea production. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic structural diagram of the present invention.

[0024] Figure 2 is Figure 1 a partial enlarged view of part A in

[0025] Figure 3 is a schematic structural diagram of the gas phase acceleration cylinder in the present invention.

[0026] Figure 4 is another schematic structural diagram of the gas phase acceleration cylinder in the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] For a clearer understanding of the technical features, objectives, and effects of the present invention, the specific embodiments of the present invention are now described with reference to the accompanying drawings. The same reference numerals in the drawings represent the same components. To make the drawings concise, only the parts related to the invention are schematically shown in each drawing, and they do not represent the actual structure of the product.

[0028] AsFigures 1-4 As shown in the figure, the present invention relates to an evaporation separator, a method thereof, and a urea production device using the same. Among them, the evaporation separator includes a separator housing 1. A volute-shaped urea solution inlet pipe 7 is provided in the middle of the separator housing 1. The volute-shaped urea solution inlet pipe 7 is connected to a urea solution inlet 10 provided on the separator housing 1. A urea solution outlet 9 is provided at the bottom of the separator housing 1. A gas phase outlet 5 is provided at the top of the separator housing 1. A separation cylinder 4 with a funnel-shaped structure is provided inside the separator housing 1. The upper part of the separation cylinder 4 is connected to the inner wall of the separator housing 1. The lower part of the separation cylinder 4 is a gas phase inlet connected to the gas phase outlet 5. A gas phase acceleration cylinder 3 is provided between the separation cylinder 4 and the gas phase outlet 5. A steam coil 2 is provided at the connection between the gas phase acceleration cylinder 3 and the separation cylinder 4. A spray head 8 is provided below the steam coil 2. The position corresponding to the lower part of the spray head 8 is the inner wall of the lower part of the separation cylinder 4.

[0029] Further, the steam coil 2 is connected to a steam pipe network provided outside the separator housing 1 through a steam pipe 6.

[0030] Further, the cross-section of the gas phase acceleration cylinder 3 is one of a rectangle or a trapezoid with a smaller upper part and a larger lower part.

[0031] Further, the upper part of the gas phase acceleration cylinder 3 is connected to the inner wall of the gas phase outlet 5.

[0032] Further, the lower part of the gas phase acceleration cylinder 3 is connected to the top of the steam coil 2.

[0033] Further, a gap 11 is provided between the steam coil 2 and the separation cylinder 4.

[0034] A method for an evaporation separator includes the following steps:

[0035] Step 1: Steam in the steam pipe network enters the steam coil 2 through the steam pipe 6 and blows the inner wall of the lower part of the separation cylinder 4 through the spray head 8.

[0036] Step 2: While the spray head 8 blows steam in Step 1, the urea solution enters the separator housing 1 through the volute-shaped urea solution inlet pipe 7 and the urea solution inlet 10 for gas-liquid separation. The liquid phase enters the next process section through the urea solution outlet 9.

[0037] Step 3: The gas phase separated in Step 2 is discharged through the gas phase inlet at the lower part of the separation cylinder 4, the gas phase acceleration cylinder 3, and the gas phase outlet 5 into the next process section.

[0038] Step 4: When the gas phase in Step 3 passes through the inner wall of the lower part of the separation cylinder 4, due to the continuous injection of steam, the gas phase cannot stay on the inner wall of the lower part of the separation cylinder 4 and no condensate can be formed.

[0039] Step 5: When the gas phase in Step 3 passes through the gap 11, due to the continuous injection of steam, the gas phase cannot enter between the separator housing 1 and the gas phase acceleration cylinder 3 and no condensate can be formed.

[0040] Step 6: When the gas phase in Step 3 passes through the gas phase acceleration cylinder 3, the gas phase is mixed with steam and the space in the gas phase acceleration cylinder 3 is small. Under the dual action of the above, the gas phase can quickly pass through the gas phase acceleration cylinder 3, avoiding the gas phase staying on the inner wall of the gas phase acceleration cylinder 3 and no condensate can be formed.

[0041] Step 7: During operation, the inside of the separator housing 1 is in a negative pressure state. Setting the gap 11 can make the pressure inside the separator housing 1 the same.

[0042] Further, in Step 1, the steam pressure in the steam pipe network is 0.3 - 0.5 MPa and the temperature is 140 - 160 °C.

[0043] Further, in Step 3, the flow rate of the gas phase passing through the gas phase inlet at the lower part of the separation cylinder 4, the gas phase acceleration cylinder 3 and the gas phase outlet 5 is not less than 7 m / s.

[0044] The present invention also provides a urea production device, including a first-stage evaporation heater and a second-stage evaporation heater, and both the first-stage evaporation heater and the second-stage evaporation heater are the evaporation separators as described above.

[0045] Through research, it is found that the current gas velocity in the separator is between 3 and 4 m / s. After the equipment is transformed by current means, the general gas velocity is about 4.5 m / s. However, the present invention treats from the generation and shedding principles of condensates to inhibit the generation of condensates and avoid the direct shedding of condensates from affecting the system. Specifically speaking, one of the reasons why condensates are generated inside the separator for urea solution is that the urine carried in the gas phase of the urea solution accumulates at the top of the separator. Over time, it will cause the generation and agglomeration of condensates. Therefore, according to this situation, by changing the internal structure of the separator, reducing the volume of the gas phase section, and increasing the gas velocity, the agglomeration of the gas phase with urine at the top of the separator can be avoided. The urine will be directly carried into the subsequent process section by the airflow and will not be washed off and enter the urea main unit system to cause fluctuations in the urine flow rate. By breaking the traditional design parameters of the separator, the present invention increases the gas velocity inside the separator, reduces the residence time of the gas phase inside the equipment, and avoids the accumulation of urine carried by the gas phase at the top of the separator, thus avoiding the generation of condensates inside the separator and ensuring the stable operation of the device. The present invention can achieve no generation of condensates inside the evaporation separator. Specifically, the urea solution in the present invention enters the separator housing 1 through the volute-type urea solution inlet pipe 7 and the urea solution inlet 10. When the urea solution enters the separator housing 1, it enters along the tangential direction to avoid the generation of condensates in the separator housing 1. The urea solution undergoes gas-liquid separation in the present invention, and the liquid phase is discharged through the urea solution outlet 9. The gas phase is discharged through the gas phase inlet at the lower part of the separation cylinder 4, the gas phase acceleration cylinder 3, and the gas phase outlet 5. The process of discharging the gas phase includes the natural operation law of the gas phase from bottom to top, increasing steam injection to prevent the gas phase from contacting the inner wall of the lower part of the separation cylinder 4 for a long time in the early stage, reducing the volume of the gas phase section, avoiding blind areas in the gas phase section, mixing steam with the gas phase to reduce the urea content in the gas phase, etc., and the state of negative pressure during operation to accelerate the gas velocity, so as to avoid the generation of condensate lumps for the gas phase with urine. At the same time, in order to ensure the same pressure inside the separator housing 1 and avoid deformation of the separation cylinder 4 and the gas phase acceleration cylinder 3 from affecting the normal operation of the equipment, a gap 11 is designed. In addition, it should be noted that the diameters of the gas phase inlet at the lower part of the separation cylinder 4, the gas phase acceleration cylinder 3, and the gas phase outlet 5 in the present invention are in a state of being the same or gradually decreasing. The steam temperature in the present invention cannot be lower than the temperature of the urea solution. To sum up, the present invention has the characteristics of less investment, simple process, and can effectively reduce the influence of condensates on the main system during urea production.

[0046] To explain the present invention in more detail, the present invention will be further elaborated in combination with embodiments. The specific embodiments are as follows:

[0047] Example 1

[0048] An evaporation separator, comprising a separator housing 1, a volute-shaped urea solution inlet pipe 7 is provided in the middle of the separator housing 1, the volute-shaped urea solution inlet pipe 7 is communicated with a urea solution inlet 10 provided on the separator housing 1, a urea solution outlet 9 is provided at the bottom of the separator housing 1, a gas phase outlet 5 is provided at the top of the separator housing 1, a separation cylinder body 4 with a funnel-shaped structure is provided inside the separator housing 1, the upper part of the separation cylinder body 4 is connected to the inner wall of the separator housing 1, and the lower part of the separation cylinder body 4 is a gas phase inlet communicated with the gas phase outlet 5; a gas phase acceleration cylinder body 3 is provided between the separation cylinder body 4 and the gas phase outlet 5, a steam coil 2 is provided at the connection between the gas phase acceleration cylinder body 3 and the separation cylinder body 4, a spray head 8 is provided below the steam coil 2, and the position corresponding to the lower part of the spray head 8 is the inner wall of the lower part of the separation cylinder body 4. The steam coil 2 is connected to a steam pipe network provided outside the separator housing 1 through a steam pipe 6. The cross section of the gas phase acceleration cylinder body 3 is one of a rectangle or a trapezoid with a smaller upper part and a larger lower part. The upper part of the gas phase acceleration cylinder body 3 is connected to the inner wall of the gas phase outlet 5. The lower part of the gas phase acceleration cylinder body 3 is connected to the top of the steam coil 2. A gap 11 is provided between the steam coil 2 and the separation cylinder body 4.

[0049] A method for an evaporation separator, comprising the following steps:

[0050] Step 1: Steam in the steam pipe network enters the steam coil 2 through the steam pipe 6, and blows the inner wall of the lower part of the separation cylinder body 4 through the spray head 8;

[0051] Step 2: While the spray head 8 blows steam in Step 1, the urea solution enters the separator housing 1 through the volute-shaped urea solution inlet pipe 7 and the urea solution inlet 10 for gas-liquid separation, and the liquid phase enters the next process section through the urea solution outlet 9;

[0052] Step 3: The gas phase separated in Step 2 is discharged into the next process section through the gas phase inlet at the lower part of the separation cylinder body 4, the gas phase acceleration cylinder body 3, and the gas phase outlet 5;

[0053] Step 4: When the gas phase in Step 3 passes through the inner wall of the lower part of the separation cylinder body 4, due to continuous steam blowing, the gas phase cannot stay on the inner wall of the lower part of the separation cylinder body 4 and no condensate can be formed;

[0054] Step 5: When the gas phase in Step 3 passes through the gap 11, due to continuous steam blowing, the gas phase cannot enter between the separator housing 1 and the gas phase acceleration cylinder body 3 and no condensate can be formed;

[0055] Step 6: When the gas phase in Step 3 passes through the gas phase acceleration cylinder 3, the gas phase is mixed with steam and the space in the gas phase acceleration cylinder 3 is small. Under the dual effects, the gas phase can quickly pass through the gas phase acceleration cylinder 3, avoiding the gas phase staying on the inner wall of the gas phase acceleration cylinder 3 and preventing the formation of condensates.

[0056] Step 7: During operation, the inside of the separator housing 1 is in a negative pressure state, and the void 11 is provided to make the pressure inside the separator housing 1 the same.

[0057] Further, in Step 1, the steam pressure in the steam pipe network is 0.3 MPa and the temperature is 140 °C.

[0058] Further, in Step 3, the flow rate of the gas phase passing through the gas phase inlet at the lower part of the separation cylinder 4, the gas phase acceleration cylinder 3, and the gas phase outlet 5 is not less than 7 m / s.

[0059] The present invention also provides a urea production device, including a first-stage evaporation heater and a second-stage evaporation heater, and both the first-stage evaporation heater and the second-stage evaporation heater are the evaporation separators as described above.

[0060] Example 2

[0061] An evaporation separator includes a separator housing 1. A volute-shaped urea solution inlet pipe 7 is provided in the middle of the separator housing 1. The volute-shaped urea solution inlet pipe 7 is connected to a urea solution inlet 10 provided on the separator housing 1. A urea solution outlet 9 is provided at the bottom of the separator housing 1. A gas phase outlet 5 is provided at the top of the separator housing 1. A separation cylinder 4 with a funnel-shaped structure is provided inside the separator housing 1. The upper part of the separation cylinder 4 is connected to the inner wall of the separator housing 1. The lower part of the separation cylinder 4 is a gas phase inlet connected to the gas phase outlet 5. A gas phase acceleration cylinder 3 is provided between the separation cylinder 4 and the gas phase outlet 5. A steam coil 2 is provided at the connection between the gas phase acceleration cylinder 3 and the separation cylinder 4. A spray head 8 is provided below the steam coil 2, and the position corresponding to the lower part of the spray head 8 is the inner wall of the lower part of the separation cylinder 4. The steam coil 2 is connected to a steam pipe network provided outside the separator housing 1 through a steam pipe 6. The cross-section of the gas phase acceleration cylinder 3 is one of a rectangle or a trapezoid with a smaller upper part and a larger lower part. The upper part of the gas phase acceleration cylinder 3 is connected to the inner wall of the gas phase outlet 5. The lower part of the gas phase acceleration cylinder 3 is connected to the top of the steam coil 2. A void 11 is provided between the steam coil 2 and the separation cylinder 4.

[0062] A method for an evaporation separator includes the following steps:

[0063] Step 1: Steam in the steam pipe network enters the steam coil 2 through the steam pipe 6 and blows the inner wall of the lower part of the separation cylinder 4 through the spray head 8.

[0064] Step 2: While the nozzle 8 blows steam in Step 1, the urea solution enters the separator housing 1 through the volute type urea solution inlet pipe 7 and the urea solution inlet 10 for gas-liquid separation. The liquid phase enters the next process section through the urea solution outlet 9.

[0065] Step 3: The gas phase separated in Step 2 is discharged through the gas phase inlet at the lower part of the separation cylinder body 4, the gas phase acceleration cylinder body 3 and the gas phase outlet 5 and enters the next process section.

[0066] Step 4: When the gas phase in Step 3 passes through the inner wall at the lower part of the separation cylinder body 4, due to continuous steam blowing, the gas phase cannot stay on the inner wall at the lower part of the separation cylinder body 4 and no condensate can be formed.

[0067] Step 5: When the gas phase in Step 3 passes through the gap 11, due to continuous steam blowing, the gas phase cannot enter between the separator housing 1 and the gas phase acceleration cylinder body 3 and no condensate can be formed.

[0068] Step 6: When the gas phase in Step 3 passes through the gas phase acceleration cylinder body 3, the gas phase is mixed with steam and the space of the gas phase acceleration cylinder body 3 is small. Under the dual action, the gas phase can quickly pass through the gas phase acceleration cylinder body 3, avoiding the gas phase staying on the inner wall of the gas phase acceleration cylinder body 3 and no condensate can be formed.

[0069] Step 7: During operation, the inside of the separator housing 1 is in a negative pressure state. The setting of the gap 11 can make the pressure inside the separator housing 1 the same.

[0070] Further, the steam pressure in the steam pipe network in Step 1 is 0.5 MPa and the temperature is 160 °C.

[0071] Further, the flow rate of the gas phase through the gas phase inlet at the lower part of the separation cylinder body 4, the gas phase acceleration cylinder body 3 and the gas phase outlet 5 in Step 3 is not less than 7 m / s.

[0072] The present invention also provides a urea production device, including a first-stage evaporation heater and a second-stage evaporation heater, and both the first-stage evaporation heater and the second-stage evaporation heater are the evaporation separators as described above.

[0073] Example Three

[0074] An evaporation separator, comprising a separator housing 1. A volute-shaped urea solution inlet pipe 7 is provided in the middle of the separator housing 1. The volute-shaped urea solution inlet pipe 7 is communicated with a urea solution inlet 10 provided on the separator housing 1. A urea solution outlet 9 is provided at the bottom of the separator housing 1. A gas phase outlet 5 is provided at the top of the separator housing 1. A separation cylinder 4 with a funnel-shaped structure is provided inside the separator housing 1. The upper part of the separation cylinder 4 is connected to the inner wall of the separator housing 1. The lower part of the separation cylinder 4 is a gas phase inlet communicated with the gas phase outlet 5. A gas phase acceleration cylinder 3 is provided between the separation cylinder 4 and the gas phase outlet 5. A steam coil 2 is provided at the connection between the gas phase acceleration cylinder 3 and the separation cylinder 4. A spray head 8 is provided below the steam coil 2. The position corresponding to the lower part of the spray head 8 is the inner wall of the lower part of the separation cylinder 4. The steam coil 2 is connected to a steam pipe network provided outside the separator housing 1 through a steam pipe 6. The cross section of the gas phase acceleration cylinder 3 is one of a rectangle or a trapezoid with a smaller upper part and a larger lower part. The upper part of the gas phase acceleration cylinder 3 is connected to the inner wall of the gas phase outlet 5. The lower part of the gas phase acceleration cylinder 3 is connected to the top of the steam coil 2. A gap 11 is provided between the steam coil 2 and the separation cylinder 4.

[0075] A method for an evaporation separator, comprising the following steps:

[0076] Step 1: Steam in the steam pipe network enters the steam coil 2 through the steam pipe 6, and blows the inner wall of the lower part of the separation cylinder 4 through the spray head 8;

[0077] Step 2: While the spray head 8 blows steam in Step 1, the urea solution enters the separator housing 1 through the volute-shaped urea solution inlet pipe 7 and the urea solution inlet 10 for gas-liquid separation. The liquid phase enters the next process section through the urea solution outlet 9;

[0078] Step 3: The gas phase separated in Step 2 is discharged through the gas phase inlet at the lower part of the separation cylinder 4, the gas phase acceleration cylinder 3, and the gas phase outlet 5 into the next process section;

[0079] Step 4: When the gas phase in Step 3 passes through the inner wall of the lower part of the separation cylinder 4, due to continuous steam blowing, the gas phase cannot stay on the inner wall of the lower part of the separation cylinder 4 and no condensate can be formed;

[0080] Step 5: When the gas phase in Step 3 passes through the gap 11, due to continuous steam blowing, the gas phase cannot enter between the separator housing 1 and the gas phase acceleration cylinder 3 and no condensate can be formed;

[0081] Step 6: When the gas phase in Step 3 passes through the gas phase acceleration cylinder 3, the gas phase is mixed with steam and the space in the gas phase acceleration cylinder 3 is small. Under the dual effects, the gas phase can quickly pass through the gas phase acceleration cylinder 3, avoiding the gas phase staying on the inner wall of the gas phase acceleration cylinder 3 and preventing the formation of condensates.

[0082] Step 7: During operation, the inside of the separator housing 1 is in a negative pressure state. The provision of the void 11 enables the pressure inside the separator housing 1 to be the same.

[0083] Further, in Step 1, the steam pressure in the steam pipe network is 0.4 MPa and the temperature is 150 °C.

[0084] Further, in Step 3, the flow rate of the gas phase passing through the gas phase inlet at the lower part of the separation cylinder 4, the gas phase acceleration cylinder 3, and the gas phase outlet 5 is not less than 7 m / s.

[0085] The present invention also provides a urea production device, including a first-stage evaporation heater and a second-stage evaporation heater, and both the first-stage evaporation heater and the second-stage evaporation heater are the evaporation separators described above.

[0086] Experimental Example

[0087] Device 1: An evaporation separator, including a separator housing 1, a volute-shaped urea solution inlet pipe 7 is provided in the middle of the separator housing 1, the volute-shaped urea solution inlet pipe 7 is connected to the urea solution inlet 10 provided on the separator housing 1, the bottom of the separator housing 1 is provided with a urea solution outlet 9, the top of the separator housing 1 is provided with a gas phase outlet 5, a separation cylinder 4 with a funnel-shaped structure is provided inside the separator housing 1, the upper part of the separation cylinder 4 is connected to the inner wall of the separator housing 1, and the lower part of the separation cylinder 4 is a gas phase inlet connected to the gas phase outlet 5; a mist eliminator is fixedly provided in the volute-shaped urea solution inlet pipe 7; and a flushing water pipe is provided; both the first-stage evaporation heater and the second-stage evaporation heater are this Device 1;

[0088] Device 2: An evaporation separator, including a separator housing 1, a volute-shaped urea solution inlet pipe 7 is provided in the middle of the separator housing 1, the volute-shaped urea solution inlet pipe 7 is connected to the urea solution inlet 10 provided on the separator housing 1, the bottom of the separator housing 1 is provided with a urea solution outlet 9, the top of the separator housing 1 is provided with a gas phase outlet 5, a separation cylinder 4 with a funnel-shaped structure is provided inside the separator housing 1, the upper part of the separation cylinder 4 is connected to the inner wall of the separator housing 1, and the lower part of the separation cylinder 4 is a gas phase inlet connected to the gas phase outlet 5; a mist eliminator is fixedly provided in the volute-shaped urea solution inlet pipe 7; the height of the housing is reduced (the housing height of Device 2 is 4 / 5 of the housing height of Device 1) and a negative pressure air suction device and a flushing water pipe are added; both the first-stage evaporation heater and the second-stage evaporation heater are this Device 2;

[0089] Device 3: Randomly select Example 3 as the group of the present invention. The first-stage evaporation heater and the second-stage evaporation heater are both in the group of the present invention.

[0090] From March 15, 2019 to June 20, 2019, the weight of the condensate cleaned out from the first-stage evaporation heater and the second-stage evaporation heater in Device 1 was 1.1 tons. The weight of the condensate cleaned out from the first-stage evaporation heater and the second-stage evaporation heater in Device 2 was 0.6 tons. After the disassembly and assembly of the first-stage evaporation heater and the second-stage evaporation heater in Device 2, the interior was smooth and there was no condensate. From the above results, it can be seen that due to Device 1 and Device 2 in Example 3 of the present invention, it can improve the overall stability of the urea production device and ensure that the equipment can operate normally and stably.

[0091] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, terms such as "connection", "connected" and the like should be understood in a broad sense. For example, it can be a fixed connection, an integral connection, or a detachable connection; it can also be the communication inside two components; it can be directly connected, or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The above examples are only specific descriptions of the feasible implementation manners of the present invention, and they are not used to limit the protection scope of the present invention. Any equivalent implementation manners, changes and modifications made without departing from the technical spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. An evaporation separator, which comprises a separator housing (1), a volute-shaped urea solution inlet pipe (7) is provided in the middle of the separator housing (1), the volute-shaped urea solution inlet pipe (7) is communicated with a urea solution inlet (10) provided on the separator housing (1), and a urea solution outlet (9) is provided at the bottom of the separator housing (1), and is characterized in that: A gas phase outlet (5) is provided at the top of the separator housing (1). A separation cylinder body (4) with a funnel-shaped structure is provided inside the separator housing (1). The upper part of the separation cylinder body (4) is connected to the inner wall of the separator housing (1), and the lower part of the separation cylinder body (4) is a gas phase inlet communicating with the gas phase outlet (5). A gas phase acceleration cylinder body (3) is provided between the separation cylinder body (4) and the gas phase outlet (5). A steam coil (2) is provided at the connection between the gas phase acceleration cylinder body (3) and the separation cylinder body (4). A spray head (8) is provided at the lower part of the steam coil (2), and the position corresponding to the lower part of the spray head (8) is the inner wall of the lower part of the separation cylinder body (4). The upper part of the gas phase acceleration cylinder body (3) is connected to the inner wall of the gas phase outlet (5). The lower part of the gas phase acceleration cylinder body (3) is connected to the top of the steam coil (2). A gap (11) is provided between the steam coil (2) and the separation cylinder body (4). The temperature of the steam in the steam coil (2) shall not be lower than the temperature of the urea solution.

2. The evaporation separator according to claim 1, characterized in that: The steam coil (2) is connected to a steam pipe network provided outside the separator housing (1) through a steam pipe (6).

3. The evaporation separator according to claim 1, wherein: The cross-section of the gas phase acceleration cylinder body (3) is one of a rectangle or a trapezoid with a smaller upper part and a larger lower part.

4. A method of an evaporation separator according to any one of claims 1-3, characterized in that: The method includes the following steps: Step 1: The steam in the steam pipe network enters the steam coil (2) through the steam pipe (6), and blows the inner wall of the lower part of the separation cylinder body (4) through the spray head (8). Step 2: While the spray head (8) blows steam in Step 1, the urea solution enters the separator housing (1) through the volute-type urea solution inlet pipe (7) and the urea solution inlet (10) for gas-liquid separation. The liquid phase enters the next process section through the urea solution outlet (9). Step 3: The gas phase separated in Step 2 is discharged through the gas phase inlet at the lower part of the separation cylinder body (4), the gas phase acceleration cylinder body (3), and the gas phase outlet (5) into the next process section. Step 4: When the gas phase in Step 3 passes through the inner wall of the lower part of the separation cylinder body (4), due to continuous steam blowing, the gas phase cannot stay on the inner wall of the lower part of the separation cylinder body (4) and cannot form condensates. Step 5: When the gas phase in Step 3 passes through the gap (11), due to continuous steam blowing, the gas phase cannot enter between the separator housing (1) and the gas phase acceleration cylinder body (3) and cannot form condensates. Step 6: When the gas phase in Step 3 passes through the gas phase acceleration cylinder body (3), the gas phase is mixed with steam and the space of the gas phase acceleration cylinder body (3) is small. Under the dual action, the gas phase can quickly pass through the gas phase acceleration cylinder body (3), avoiding the gas phase staying on the inner wall of the gas phase acceleration cylinder body (3) and unable to form condensates. Step 7: During operation, the inside of the separator housing (1) is in a negative pressure state. Setting the gap (11) can make the pressure inside the separator housing (1) the same.

5. A method for an evaporation separator according to claim 4, characterized in that: In Step 1, the steam pressure in the steam pipe network is 0.3 - 0.5 MPa, and the temperature is 140 - 160 °C.

6. A method of an evaporation separator according to claim 4, characterized in that: The flow rate of the gas phase passing through the gas phase inlet at the lower part of the separation cylinder body (4), the gas phase acceleration cylinder body (3), and the gas phase outlet (5) in the step 3 is not less than 7 m / s.

7. A urea production device, characterized in that: It includes a first-stage evaporation heater and a second-stage evaporation heater, and both the first-stage evaporation heater and the second-stage evaporation heater are evaporation separators as described in any one of claims 1-3.

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