Based on N 2 Method for optimizing main condenser of molecular air separation

Abstract

The invention relates to the technical field of air separation equipment, and in particular to a method for optimizing a molecular air separation main condenser based on N2O, comprising: calculating a standard content of N2O according to the purity of liquid oxygen in the main condenser; comparing the standard content with the N2O content to judge whether the liquid oxygen is sufficiently discharged; calculating a solid precipitation content value of N2O according to the pressure in the main condenser and the temperature of the liquid oxygen; drawing a N2O content change curve, determining a change trend of the N2O content, and judging a risk level of solid precipitation of N2O; arranging an auxiliary condenser to discharge N2O in the liquid oxygen of the main condenser; adjusting a condenser cleaning cycle according to an integral value of the N2O content curve and the solid precipitation content; monitoring the N2O content in real time and adjusting operating parameters of an air separation device, and reducing the accumulation of N2O and the solid precipitation risk by formulating regular condenser cleaning and N2O emission strategies to prevent N2O from reaching a solidification point.

Description

Technical Field

[0001] The present invention relates to the technical field of air separation equipment, in particular to a method for separating air from a substrate by using N 2 OMethod for optimizing the main condenser of molecular air separation. Background Art

[0002] The molecular formula of nitrous oxide is N 2 O, also known as nitrous oxide, commonly known as "laughing gas". The concentration of nitrous oxide in the atmosphere is about 3×10 -9 With the deterioration of the ecological environment, its content increases at a rate of 0.2% to 0.3% per year. 2 Near the O generation source, N 2 The content of O can reach 3×10 -6 Above. Although N 2 O is chemically inactive and will neither cause corrosion nor explosion, but its physical properties are harmful to air separation. Its critical temperature is 309.7K, its critical pressure is 7.27MPa, and its triple point is 182.3K and 0.088MPa. Under the pressure and temperature conditions of the air separation unit, it has the property of sublimation. At normal pressure, its boiling point is 185K, which is lower than N 2 , O 2 The boiling points of Ar are high, so during the separation of oxygen and nitrogen, it will be concentrated in liquid oxygen.

[0003] N 2 O has a low solubility in water, 2 O cannot be separated or removed after passing through the air filter, compressor, cooler, and water separator with the processed air. Most of N 2 O will be brought into the molecular sieve purifier, and the molecular sieve will 2 The adsorption capacity of O is lower than that of CO 2 The adsorption capacity of N 2 O first penetrates the adsorption bed and enters the distillation tower, and the molecular sieve 2 O、CO 2 , C 2 H 2 In the co-adsorption process of hydrocarbons such as CO 2 It can absorb the N adsorbed by molecular sieve 2 O molecules are replaced.

[0004] Chinese Patent Publication No.: CN202547277U discloses a main condenser evaporator of an air separation device, which includes at least a first cavity, a second cavity and at least one cavity pair from top to bottom, each cavity pair is composed of an upper cavity and a lower cavity, wherein the first cavity includes a first overflow port arranged on the side wall of the first cavity at a predetermined height from the bottom, and at least one outflow port; the second cavity is connected to the first cavity through the first overflow port, and includes a second overflow port arranged on the side wall of the second cavity at a predetermined height from the bottom; the upper cavity in the at least one cavity pair is connected to the first cavity through at least one outflow port, and includes an upper cavity overflow port arranged on the side wall of the upper cavity at a predetermined height from the bottom; the lower cavity in the at least one cavity pair is connected to the upper cavity in the at least one cavity pair through the upper cavity overflow port, and includes a lower cavity overflow port arranged on the side wall of the lower cavity in the at least one cavity pair at a predetermined height from the bottom.

[0005] It can be seen that the main condenser evaporator under the current technology has the following problems:

[0006] In the distillation tower, because N 2 O vs. N 2 , O 2 , Ar component is a high boiling point component, so it will dissolve in liquid oxygen, resulting in the inability to obtain high-purity liquid oxygen and gaseous oxygen products at the bottom of the upper tower. 2 O accumulates in liquid oxygen. 2 O content is greater than 50×10 -6 When it is condensed, it will precipitate in solid form and block the main condenser evaporator channel. Summary of the invention

[0007] To this end, the present invention provides a method based on N 2 O Method for optimizing the main condenser of molecular air separation to overcome the problem in the prior art that when the liquid oxygen is not discharged sufficiently, N 2 O accumulates in liquid oxygen. 2 O content is greater than 50×10 -6 When it is condensed, it will precipitate in solid form and block the main condenser evaporator channel.

[0008] To achieve the above object, the present invention provides a method based on N 2 The method for optimizing the main condenser of molecular air separation comprises the following steps:

[0009] Detect the purity of liquid oxygen in the main condenser and calculate N based on the purity of liquid oxygen in the main condenser 2 Standard content of O;

[0010] Sampling and analysis of liquid oxygen in the main condenser to detect N in the liquid oxygen in the main condenser in real time 2O content, N in liquid oxygen 2 The O content is compared with the standard content, and whether the liquid oxygen discharge is sufficient is judged according to the comparison result to determine the liquid oxygen discharge rate;

[0011] Detect the pressure in the main condenser and the temperature of liquid oxygen in the main condenser, and calculate the N 2 Solid precipitation content of O;

[0012] According to the real-time detection of N 2 O content draws the content change curve and calculates the N content in liquid oxygen 2 The derivative function of the O content change curve;

[0013] N in liquid oxygen 2 The corresponding N 2 O content value is compared with the solid precipitation content value, and the N 2 Determine the N content in liquid oxygen by taking the derivative of the O content curve 2 The change trend of the O content change curve is used to judge the solid precipitation risk level based on the comparison results and the change trend to determine the pressure in the main condenser;

[0014] Set up the auxiliary discharge unit in liquid oxygen N 2 When O is at risk of solid precipitation, reduce the N content in the main condenser liquid oxygen 2 O content;

[0015] Calculate the N in the condenser liquid oxygen 2 O content curve and N in liquid oxygen 2 The integral value of the surface surrounded by the O solid precipitation content value is used to determine the condenser cleaning cycle based on the calculation results.

[0016] Furthermore, the purity of liquid oxygen in the main condenser is detected, and the purity of liquid oxygen in the main condenser is compared with the purity of N in the standard liquid oxygen. 2 Calculation of average O content 2 The standard content of O.

[0017] Furthermore, when N 2 When comparing the O content with the standard content,

[0018] If N in liquid oxygen 2 The O content is greater than the N content in liquid oxygen 2 O standard content, then determine the N content in liquid oxygen 2 The O content exceeds the standard content range, the liquid oxygen discharge is insufficient, and the liquid oxygen discharge rate in the distillation tower is increased.

[0019] Furthermore, the pressure in the main condenser and the temperature of liquid oxygen in the main condenser are detected. According to the N 2The solid precipitation content of O is calculated by the N content of liquid oxygen at the detected pressure temperature. 2 The solid precipitation content value of O.

[0020] Furthermore, when N 2 The corresponding N 2 O content and N in liquid oxygen 2 When comparing the solid precipitation content of O,

[0021] If N 2 O content is less than the solid precipitation content value, then it is judged that N 2 O content does not reach the solid precipitation content value. According to the content change curve, N 2 The change trend of O content is used to make a secondary risk assessment on the solid precipitation risk level;

[0022] If N 2 O content is greater than or equal to the solid precipitation content value, then it is judged that N 2 The O content has reached the solid precipitation content value, and the N 2 O solid precipitation, the main condenser has the risk of solid precipitation, according to the content change curve of N 2 The risk level is determined by the changing trend of O content.

[0023] Further, according to the content change curve of N 2 The change trend of O content is used for secondary risk assessment, among which:

[0024] If N 2 The derivative of the O content is less than zero, so it is determined that N 2 O No risk of solid precipitation, the correction parameter of the content change curve is equal to zero;

[0025] If N 2 The derivative of the O content is greater than or equal to zero, and it is determined that the main condenser is at the first risk level of solid precipitation, and the content change curve correction parameter is equal to the first preset value of the content change curve correction parameter.

[0026] Further, according to the content change curve of N 2 The changing trend of O content determines the risk level.

[0027] If N 2 The derivative of the O content is less than zero, and it is determined that the main condenser is at the second risk level of solid precipitation, and the content change curve correction parameter is equal to the second preset value of the content change curve correction parameter;

[0028] If N 2If the derivative of the O content is greater than or equal to zero, the main condenser is judged to be at the third level of solid precipitation risk and an alarm message is issued.

[0029] Furthermore, when the main condenser is at risk of solid precipitation, the internal pressure of the main condenser is determined according to the solid precipitation risk level. By increasing the internal pressure of the main condenser, the boiling temperature of liquid oxygen increases, thereby increasing the N 2 The solubility of O.

[0030] Furthermore, an auxiliary discharge unit is provided to be connected to the main condenser, wherein the auxiliary discharge unit includes an auxiliary condenser and a discharger. 2 When there is a risk level of solid precipitation, the liquid oxygen at the bottom of the main condenser is transferred to the auxiliary condenser and led to the discharger. The liquid oxygen accumulated at the bottom of the discharger is discharged regularly.

[0031] Furthermore, for N 2 The O content change curve is analyzed, and the integral expression parameters of the content change curve are determined according to the analysis results.

[0032] At any time point, if the content of the content change curve is less than the solid precipitation content, the integral expression parameter is zero; if the content of the content change curve is greater than or equal to the solid precipitation content, the integral expression parameter is the preset value, which is consistent with N 2 The difference between the O content and the solid precipitation content is positively correlated.

[0033] Furthermore, a condenser cleaning cycle is set to calculate the N 2 O content curve and N 2 The integral value of the solid precipitation content of O is used to determine the adjusted condenser cleaning cycle based on the calculation result of the integral value.

[0034] Compared with the prior art, the invention has the following beneficial effects: specifically, N 2 The content of O is affected by the purity of liquid oxygen. According to the purity of liquid oxygen in the main condenser and the N content in liquid oxygen at the standard liquid oxygen purity, 2 O content, calculate the N 2 O content, increases the accuracy of the invention; and by 2 O content and N in liquid oxygen 2 O standard content to judge whether the liquid oxygen discharge is sufficient. When the liquid oxygen discharge is insufficient, N 2 O accumulates continuously in liquid oxygen, and its content increases continuously. Adjust the liquid oxygen discharge rate, increase the liquid oxygen discharge volume, and reduce N 2 O content in liquid oxygen.

[0035] Furthermore, N in liquid oxygen 2The solid precipitation content of O is affected by the pressure in the main condenser and the temperature of the liquid oxygen in the main condenser. The N in the liquid oxygen at the current pressure in the main condenser and the temperature of the liquid oxygen is calculated based on the detected pressure in the main condenser, the temperature of the liquid oxygen in the main condenser and the standard parameters. 2 The solid precipitation content value of O increases the accuracy of the invention.

[0036] Furthermore, part of the liquid oxygen in the main condenser is extracted for liquid oxygen sampling and analysis; according to the detected N 2 O content, plotting N in liquid oxygen 2 O content change curve, and calculate the N in liquid oxygen 2 The derivative of the O content change curve; N 2 O content change curve real-time content value and N in liquid oxygen 2 O solid precipitation content values ​​are compared, and according to N 2 The derivative of the real-time content value of the O content change curve determines the N content in liquid oxygen 2 The changing trend of the O content curve has increased the N 2 The accuracy of prediction of O content;

[0037] According to the predicted N in liquid oxygen 2 The trend of the change curve of O content is 2 The solid precipitation risk level of O is evaluated and the N 2 The expression parameters of the O content change curve are based on the N 2 The risk level of solid precipitation of O is adjusted by adjusting the pressure in the main condenser, increasing the boiling temperature of liquid oxygen, and increasing the N 2 The solubility of O decreases, 2 Risk of solid precipitation of O.

[0038] Specifically, by setting up an auxiliary condenser and regularly cleaning the main condenser evaporator, N 2 O accumulation causes blockage of the main condenser evaporator, thereby ensuring the safety of the main condenser evaporator and increasing the practicality of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 In the embodiment of the present invention, based on N 2 O Step diagram of the method for optimizing the main condenser of molecular air separation;

[0040] Figure 2 In the embodiment of the present invention, according to N 2 Flow chart of adjusting liquid oxygen discharge rate with O content;

[0041] Figure 3 In the embodiment of the present invention, according to N 2 O content change curve to judge N2 Flowchart of O solid precipitation risk. DETAILED DESCRIPTION

[0042] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0043] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0044] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0045] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] See also Figure 1 As shown, it is based on N in the embodiment of the present invention. 2 O Step diagram of the method for optimizing the main condenser of molecular air separation;

[0047] The embodiment of the present invention provides a method based on N 2 A method for optimizing a main condenser of a molecular air separation system, comprising:

[0048] Step S1, detecting the purity of liquid oxygen in the main condenser, and calculating N according to the purity of liquid oxygen in the main condenser 2 Standard content of O;

[0049] Step S2, sampling and analyzing the liquid oxygen in the main condenser, and detecting the N 2 O content, N in liquid oxygen 2 The O content is compared with the standard content, and whether the liquid oxygen discharge is sufficient is judged according to the comparison result to determine the liquid oxygen discharge rate;

[0050] Step S3, detecting the pressure in the main condenser and the temperature of the liquid oxygen in the main condenser, and calculating the N 2 Solid precipitation content of O;

[0051] Step S4: according to the real-time detection of N in the main condenser liquid oxygen 2 O content draws the content change curve and calculates the N content in liquid oxygen 2 The derivative function of the O content change curve;

[0052] Step S5, N 2 The corresponding N 2 O content value is compared with the solid precipitation content value, and the N 2 Determine the N content in liquid oxygen by taking the derivative of the O content curve 2 The change trend of the O content change curve is used to judge the solid precipitation risk level based on the comparison results and the change trend to determine the pressure in the main condenser;

[0053] Step S6, setting the auxiliary discharge unit in liquid oxygen N 2 When O is at risk of solid precipitation, reduce the N content in the main condenser liquid oxygen 2 O content;

[0054] Step S7, calculate the N in the condenser liquid oxygen 2 O content curve and N in liquid oxygen 2 The integral value of the surface surrounded by the O solid precipitation content value is used to determine the condenser cleaning cycle based on the calculation results.

[0055] Specifically, extract part of the liquid oxygen in the main condenser for liquid oxygen sampling and analysis, detect the purity of the liquid oxygen in the main condenser, and calculate N based on the purity of the liquid oxygen in the main condenser. 2 The standard content of O provides a standard parameter. According to the measurement, when the purity of liquid oxygen Hp is 99.5%, N 2 The average O content Gp is ​​1.4×10 -5 , set the purity of liquid oxygen in the main condenser to H1, and the purity of N 2 The standard content of O is Gb, Gb=H1÷Hp×Gp×b1, where b1 is the N content in liquid oxygen. 2 Calculation correction parameters for O standard content Gb.

[0056] Extract part of the liquid oxygen in the main condenser for liquid oxygen sampling and analysis, and use a thermal conductivity detector to detect the N in the liquid oxygen. 2 O content G1, N in liquid oxygen 2 O content G1 and N in liquid oxygen 2 O standard content Gb for comparison:

[0057] If G1≤Gb, then determine the N 2The O content G1 is within the normal range and liquid oxygen is discharged sufficiently.

[0058] If G1>Gb, then determine the N in liquid oxygen 2 O content G1 exceeds the normal range, and insufficient liquid oxygen discharge leads to N 2 O accumulates continuously in liquid oxygen, increasing the liquid oxygen discharge rate V0. Suppose the adjusted liquid oxygen discharge rate is V1, V1=G1÷Gb×V0.

[0059] Specifically, N in liquid oxygen 2 The content of O is affected by the purity of liquid oxygen. According to the purity of liquid oxygen in the main condenser and the N content in liquid oxygen at the standard liquid oxygen purity, 2 O content, calculate the N 2 O content, increases the accuracy of the invention; and by 2 O content and N in liquid oxygen 2 O standard content to judge whether the liquid oxygen discharge is sufficient. When the liquid oxygen discharge is insufficient, N 2 O accumulates continuously in liquid oxygen, and its content increases continuously. Adjust the liquid oxygen discharge rate, increase the liquid oxygen discharge volume, and reduce N 2 O content in liquid oxygen.

[0060] Specifically, the current pressure P0 in the main condenser and the liquid oxygen temperature T0 in the main condenser are detected, and the N in the liquid oxygen is calculated according to the current pressure P0 and the liquid oxygen temperature T0 in the main condenser. 2 The solid precipitation content of O provides a standard parameter. When the pressure Pb in the main condenser is 0.6MPa and the liquid oxygen temperature Tb is 83K, N 2 The solid precipitation content of O is 5×10 -5 , set the liquid oxygen N in the current main condenser pressure P0 and liquid oxygen temperature T0 2 The solid precipitation content of O is Ge, Ge=P0÷Pb×Tb÷T0×Ge1×c1, where c1 is the N in liquid oxygen. 2 Correction parameters for calculating the solid precipitation content of O.

[0061] Specifically, N in liquid oxygen 2 The solid precipitation content of O is affected by the pressure in the main condenser and the temperature of the liquid oxygen in the main condenser. The N in the liquid oxygen at the current pressure in the main condenser and the temperature of the liquid oxygen is calculated based on the detected pressure in the main condenser, the temperature of the liquid oxygen in the main condenser and the standard parameters. 2 The solid precipitation content value of O increases the accuracy of the invention.

[0062] Specifically, part of the liquid oxygen in the main condenser was extracted for liquid oxygen sampling and analysis, and the N 2O content G1, according to the N in liquid oxygen 2 O content G1 draws N in liquid oxygen 2 The variation curve of O content G1 is F(x), and the derivative function of the content variation curve F(x) is f(x).

[0063] For the content variation curve F(x) of N in liquid oxygen 2 O real-time content analysis, N 2 O real-time content value and N in liquid oxygen 2 The solid precipitation content of O Ge is compared:

[0064] If F(t)<Ge, then determine the N in liquid oxygen 2 O content G1 does not reach the solid precipitation content value,

[0065] Among them, if f(t)<0, it is judged that N in liquid oxygen 2 O content G1 is decreasing, N in liquid oxygen 2 ONo risk of solid precipitation, α=0.

[0066] If f(t) = 0, then determine the N 2 O content G1 remains unchanged, N in liquid oxygen 2 ONo risk of solid precipitation, α=0.

[0067] If f(t)>0, then determine the N 2 The O content G1 is rising, and the air separation main condenser is at the first risk level of solid precipitation, α=α1.

[0068] If F(t)≥Ge, then determine the N 2 The O content G has reached the solid precipitation content value, and the N 2 O solid precipitation, the main condenser of air separation needs to be cleaned,

[0069] Among them, if f(t)<0, it is judged that N in liquid oxygen 2 The O content G1 is decreasing, and the air separation main condenser is at the second risk level of solid precipitation, α=α2.

[0070] If f(t)=0, then determine the N 2 The O content G1 remains unchanged, and the air separation main condenser is at the second level of solid precipitation risk, α=α2;

[0071] If f(t)>0, then determine the N 2 The O content G1 continued to rise, and the air separation main condenser was at the third level of solid precipitation risk, and an alarm message was issued to notify the management personnel to handle it;

[0072] Where F(t) is the N of the content change curve at any time point t2 O content value, f(t) is the slope of the content change curve at any time point t, and α is the content expression parameter of the content change curve.

[0073] For the expression parameter α of the content change curve, its value is related to the corresponding N 2 O content G1 is related to the N content of different liquid oxygen 2 The O content sets expression parameters for different content change curves, α1 is the preset value of the content expression parameter when the solid precipitation has the first risk level, α2 is the preset value of the content expression parameter when the solid precipitation has the second risk level, and α2>α1.

[0074] Specifically, when the air separation main condenser is at the risk of solid precipitation, the internal pressure P0 of the air separation main condenser is adjusted. Assume that the adjusted internal pressure of the air separation main condenser is P1. When the air separation main condenser is at the first risk level of solid precipitation, P1=Ge÷G1×P0×α. When the air separation main condenser is at the second risk level of solid precipitation, P1=G1÷Ge×P0×α. By increasing the internal pressure of the air separation main condenser, the boiling temperature of liquid oxygen is increased, thereby increasing the N 2 The solubility of O reduces the N 2 Risk of solid precipitation of O.

[0075] Specifically, part of the liquid oxygen in the main condenser is extracted for liquid oxygen sampling and analysis; according to the detected N 2 O content, plotting N in liquid oxygen 2 O content change curve, and calculate the N in liquid oxygen 2 The derivative of the O content change curve; N 2 O content change curve real-time content value and N in liquid oxygen 2 O solid precipitation content values ​​are compared, and according to N 2 The derivative of the real-time content value of the O content change curve determines the N content in liquid oxygen 2 The changing trend of the O content curve has increased the N 2 The accuracy of O content prediction.

[0076] According to the predicted N in liquid oxygen 2 The trend of the change curve of O content is 2 The solid precipitation risk level of O is evaluated and the N 2 The expression parameters of the O content change curve are based on the N 2 The risk level of solid precipitation of O is adjusted by adjusting the pressure in the main condenser, increasing the boiling temperature of liquid oxygen, and increasing the N 2 The solubility of O decreases, 2 Risk of solid precipitation of O.

[0077] Specifically, an auxiliary discharge unit is connected to the main condenser of the air separation system. The auxiliary discharge unit consists of an auxiliary condenser and an discharger. 2 When O is at the first risk level of solid precipitation and the second risk level of solid precipitation, the liquid oxygen at the bottom of the main condenser is transferred to the auxiliary condenser for evaporation. As the liquid oxygen in the auxiliary condenser evaporates, the purity of the liquid oxygen gradually decreases, and the N 2 O content continues to increase. 2 Liquid oxygen with a higher O concentration is led to the ejector, accumulated at the bottom of the ejector and discharged periodically.

[0078] Specifically, for N in liquid oxygen 2 The O content change curve F(x) is analyzed and the integral expression parameters are determined based on the analysis results.

[0079] If F(t)<Ge, then β=β1;

[0080] If F(t)≥Ge, then β=β2;

[0081] Where F(t) is the N of the content change curve at any time point t 2 O content value, β1=0, β2 and N 2 The difference between the O content and the solid precipitation content is positively correlated.

[0082] Set the condenser cleaning cycle T0 and calculate the N in the condenser liquid oxygen 2 O content curve and N in liquid oxygen 2 The integral value of the solid precipitation content of O is used to adjust the condenser cleaning cycle T0 according to the calculation results. Suppose that the N 2 O content curve F(x) and N in liquid oxygen 2 The integral value of O solid precipitation content Ge is △G, △G= ; If △G>0, assume that the adjusted cleaning cycle is T1, T1=△G÷Ge×T0×b1, where b1 is the calculation correction parameter for calculating the adjusted cleaning cycle T1.

[0083] Specifically, by setting up an auxiliary condenser and regularly cleaning the main condenser evaporator, N 2 O accumulation causes blockage of the main condenser evaporator, thereby ensuring the safety of the main condenser evaporator and increasing the practicality of the present invention.

[0084] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0085] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for optimizing the main condenser of molecular air separation based on N2O, characterized in that: include: Detect the purity of liquid oxygen in the main condenser and calculate the standard content of N2O based on the purity of liquid oxygen in the main condenser; Sampling and analyzing the liquid oxygen in the main condenser, detecting the N2O content in the liquid oxygen in the main condenser in real time, comparing the N2O content in the liquid oxygen with the standard content, judging whether the liquid oxygen discharge is sufficient according to the comparison result, so as to determine the liquid oxygen discharge rate; Detect the pressure in the main condenser and the temperature of liquid oxygen in the main condenser, and calculate the solid precipitation content of N2O in liquid oxygen; Draw a content change curve according to the real-time detected N2O content in the liquid oxygen of the main condenser, and calculate the derivative function of the N2O content change curve in the liquid oxygen; Compare the corresponding N2O content value in the N2O content change curve in liquid oxygen with the solid precipitation content value, determine the change trend of the N2O content change curve in liquid oxygen by the derivative of the N2O content change curve, judge the solid precipitation risk level according to the comparison result and the change trend, and determine the pressure in the main condenser; Among them, when N2O in liquid oxygen is at risk of solid precipitation, the N2O content in the liquid oxygen of the main condenser is reduced; Calculate the integral value of the surface formed by the N2O content curve in the condenser liquid oxygen and the N2O solid precipitation content value in the liquid oxygen, and determine the condenser cleaning cycle based on the calculation results.

2. The method for optimizing the main condenser of molecular air separation based on N2O according to claim 1, characterized in that: The purity of liquid oxygen in the main condenser is detected, and the standard content of N2O is calculated according to the purity of liquid oxygen in the main condenser and the average content of N2O in the standard liquid oxygen purity.

3. The method for optimizing the main condenser of molecular air separation based on N2O according to claim 2, characterized in that: When comparing the N2O content in liquid oxygen with the standard content, If the N2O content in the liquid oxygen is greater than the standard N2O content in the liquid oxygen, it is determined that the N2O content in the liquid oxygen exceeds the standard content range, the liquid oxygen discharge is insufficient, and the liquid oxygen discharge rate in the distillation tower is increased.

4. The method for optimizing the main condenser of molecular air separation based on N2O according to claim 3, characterized in that: The pressure in the main condenser and the temperature of the liquid oxygen in the main condenser are detected, and the solid precipitation content value of N2O in the liquid oxygen at the detected pressure temperature is calculated according to the solid precipitation content value of N2O at the standard pressure temperature.

5. The method for optimizing the main condenser of molecular air separation based on N2O according to claim 4, characterized in that: When comparing the corresponding N2O content value in the N2O content change curve in liquid oxygen with the solid precipitation content value of N2O in liquid oxygen, If the N2O content in the content change curve is less than the solid precipitation content value, it is judged that the N2O content in the liquid oxygen has not reached the solid precipitation content value, and a secondary risk determination is performed on the solid precipitation risk level according to the change trend of the N2O content in the content change curve; If the N2O content in the content change curve is greater than or equal to the solid precipitation content value, it is judged that the N2O content in the liquid oxygen has reached the solid precipitation content value, N2O in the liquid oxygen in the main condenser is precipitated in the solid state, and there is a solid precipitation risk in the main condenser. The risk level is determined based on the changing trend of the N2O content in the content change curve.

6. The method for optimizing the main condenser of molecular air separation based on N2O according to claim 5, characterized in that: A secondary risk assessment is performed based on the changing trend of N2O content in the content change curve, where: If the derivative of the N2O content in the content change curve is less than zero, it is determined that there is no risk of solid precipitation of N2O in the liquid oxygen, and the correction parameter of the content change curve is equal to zero; If the derivative of the N2O content in the content change curve is greater than or equal to zero, it is determined that the main condenser is at the first risk level of solid precipitation, and the content change curve correction parameter is equal to the first preset value of the content change curve correction parameter.

7. The method for optimizing the main condenser of molecular air separation based on N2O according to claim 6, characterized in that: Determine the risk level based on the changing trend of N2O content in the content change curve. If the derivative of the N2O content in the content change curve is less than zero, it is determined that the main condenser is at the second risk level of solid precipitation, and the content change curve correction parameter is equal to the second preset value of the content change curve correction parameter; If the derivative of the N2O content in the content change curve is greater than or equal to zero, the main condenser is judged to be at the third level of solid precipitation risk and an alarm message is issued.

8. The method for optimizing the main condenser of molecular air separation based on N2O according to claim 7, characterized in that: When the main condenser is at risk of solid precipitation, the internal pressure of the main condenser is determined according to the solid precipitation risk level. By increasing the internal pressure of the main condenser, the boiling temperature of liquid oxygen increases, thereby increasing the solubility of N2O in liquid oxygen.

9. The method for optimizing the main condenser of molecular air separation based on N2O according to claim 8, characterized in that: An auxiliary discharge unit is arranged to be connected to the main condenser, and the auxiliary discharge unit includes an auxiliary condenser and an discharger. When there is a risk level of solid precipitation of N2O in the liquid oxygen in the main condenser, the liquid oxygen at the bottom of the main condenser is transferred to the auxiliary condenser and led to the discharger. The liquid oxygen accumulated at the bottom of the discharger is discharged regularly.

10. The method for optimizing the main condenser of molecular air separation based on N2O according to claim 9, characterized in that: The N2O content change curve in liquid oxygen is analyzed, and the integral expression parameters of the content change curve are determined based on the analysis results. At any time point, if the content of the content change curve is less than the solid precipitation content, the integral expression parameter is zero; if the content of the content change curve is greater than or equal to the solid precipitation content, the integral expression parameter is a preset value, which is positively correlated with the difference between the N2O content value and the solid precipitation content value.

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