A method for controlling the explosion limit of cyclohexanone in the preparation of epsilon-caprolactone

Abstract

The application aims to provide a kind of cyclohexanone preparation epsilon-caprolactone intrinsic safety explosion limit control method, the technical problem of chemical production intrinsic safety to be solved;Its technical scheme: one) cyclohexanone, benzaldehyde, metal porphyrin catalyst, solvent are added to high pressure reactor, at 0.5-4MPa, 50-70 DEG C reaction obtains gas-liquid mixed reaction liquid;Two) input the chemical name used before and after reaction in Aspen Plus chemical simulation software, and based on cyclohexanone, epsilon-caprolactone binary gas-liquid equilibrium selects NRTL property model, determines pure component and binary parameter, establishes cyclohexanone, epsilon-caprolactone reaction separation process, runs model and analyzes stream data;Three) according to each material in stream and its content, based on the explosion limit formula of le chatelier, the explosion limit of each stream mixed flammable gas is calculated;Through the explosion limit calculation result of each gas phase stream, the air feed amount is determined by comparison and feedback;Belongs to fine chemical technology field.

Description

TECHNICAL FIELD

[0001] The application discloses a cyclohexanone epsilon-caprolactone intrinsic safety explosion limit control method, which adopts fine chemical technology. BACKGROUND

[0002] In industrial production, mixed combustible gas is transported and leaked in pipelines. In this process, combustible gas explosion hazards exist, mainly because combustible gas leaks out, mixes with air to form combustible mixed gas with a suitable concentration, is ignited by a fire source medium, and causes combustion, deflagration or even detonation. In general, the pipeline for transporting combustible gas is safe, because the combustible and explosive gas transported in the pipeline network is pure gas without doping oxygen or other oxidizing agents. However, in the process of green fine chemical production, many existing processes need to use oxygen as an oxidizing agent and nitrogen as a protective gas. Combustible gas explosion needs to meet the condition that the combustible gas is in the explosion limit, i.e. in the lower explosion limit and the upper explosion limit. If the combustible gas is in the explosion limit, a flame or explosion will occur when it encounters a fire, lightning or other combustion conditions, causing serious safety accidents.

[0003] In the face of the problem of controlling the explosion limit of mixed gas, enterprises often avoid using air as an oxidizing agent in industrial production, and instead use liquid oxidizing agents. However, liquid oxidizing agents will produce a lot of liquid waste in the reaction and subsequent separation process, reducing the purity of the product and increasing the difficulty of integrating the process to be green and environmentally friendly. However, air as an oxidizing agent is different, air is recyclable and affordable, and will not produce too much waste in the reaction and separation process. The gas after the reaction is mainly nitrogen, which can be directly discharged and will not have adverse effects on the entire process. In the aspect of seeking green environmental protection, it also plays a good leading role.

[0004] In view of the above problems, the purpose of the present application is to develop a set of intrinsic safety explosion limit control method in chemical production, which is a cyclohexanone epsilon-caprolactone intrinsic safety explosion limit control method. SUMMARY

[0005] In view of the deficiencies in the prior art, the purpose of the present application is to provide a cyclohexanone epsilon-caprolactone intrinsic safety explosion limit control method, which aims to solve the problem of combustible gas explosion limit control in the process of preparing epsilon-caprolactone from cyclohexanone.

[0006] The purpose of the present application is achieved by the following scheme:

[0007] A cyclohexanone epsilon-caprolactone intrinsic safety explosion limit control method,

[0008] i) cyclohexanone, benzaldehyde, metalloporphyrin catalyst, solvent are added into a high-pressure reactor, and a gas-liquid mixed reaction liquid is obtained at 0.5-4 MPa and 50-70 DEG C;

[0009] ii) chemical names used before and after the reaction are input into Aspen Plus chemical simulation software, NRTL property model is selected based on cyclohexanone and epsilon-caprolactone binary gas-liquid equilibrium, pure components and binary parameters are determined, a cyclohexanone and epsilon-caprolactone reaction and separation process is established, the model is run, and stream data are analyzed;

[0010] The NRTL is an activity coefficient model.

[0011] iii) based on the substances and contents in the streams, the explosion limit of the combustible gas mixture in each stream is calculated based on the Le Chatelier explosion limit formula; the air feed amount is determined by comparing and feeding back the calculation results of the explosion limit of each gas phase stream.

[0012] Further, in the method, the mass ratio of the cyclohexanone to the benzaldehyde is 1-2:2-3.

[0013] Further, in the method, the solvent is one of n-butane, cyclohexane, acetonitrile, methyl benzoate, and toluene.

[0014] Further, in the method, step i) is specifically as follows:

[0015] 1) the cyclohexanone is pumped into a first stream, the benzaldehyde is pumped into a second stream, the metalloporphyrin catalyst and the solvent are pumped into a third stream, and the three streams are mixed uniformly in a mixing tank;

[0016] 2) a gas path valve of a microchannel reactor is opened, the air flow rate of a fourth stream is set to 20 mL / min, a temperature is set to 50-70 DEG C on a circulating device, the temperature in the microchannel reactor reaches the set value, the air flow rate of the fourth stream is adjusted to 70 mL / min, then a liquid path valve is opened, and the mixed liquid of the cyclohexanone, the benzaldehyde, the metalloporphyrin catalyst, and the solvent is pumped into the reactor through a sixth stream at a speed of 5 mL / min for 5 min;

[0017] 3) the microchannel reactor is purged by the high-pressure gas flow of the fourth stream for 5 min;

[0018] 4) after the purging, the air flow rate of the fourth stream is adjusted to 85 mL / min, then the liquid path valve is opened, and the mixed liquid is pumped into the reactor through the sixth stream at a speed of 7 mL / min;

[0019] 5) The 8th stream of reaction solution is cooled by a heat exchanger and then enters the 9th stream. The reaction solution in the 9th stream is introduced into a three-necked flask. One branch of the three-necked flask is connected to the 10th stream for exhaust, and the other branch is connected to the 11th stream for collecting the product.

[0020] Further, in the above-mentioned method for controlling the explosion limit of the preparation of ε-caprolactone from cyclohexanone, the reaction and separation process of cyclohexanone and ε-caprolactone in step ii) is as follows: the product in the 11th stream is introduced into the 12th stream through a pressure-reducing valve, the product in the 12th stream is separated by a rectification and deacidification tower, the incondensable gas is introduced into the 13th stream, the light component is introduced into the 14th stream, and the heavy component is introduced into the 15th stream; the light component in the 14th stream is introduced into the 16th stream through a pump, the component in the 16th stream is separated by a rectification and light component removal tower, the light component is introduced into the 17th stream, the heavy component is introduced into the 18th stream, the light component in the 17th stream is introduced into the 19th stream through a pump, and the light component in the 19th stream is recycled back to the mixing tank.

[0021] Further, in the above-mentioned method for controlling the explosion limit of the preparation of ε-caprolactone from cyclohexanone, the analysis method of each substance in the stream is as follows: a gas chromatography column HT-FFAP is selected, the column volume is 30m x 0.25mm x 0.25μm, the column temperature is 20℃-240℃, the vaporization chamber temperature is set to 240℃, the detection chamber temperature is set to 240℃, the carrier gas is 99.999% high-purity nitrogen, the split ratio is set to 30:1, the air is a GA-2009 air generator, the hydrogen is a HF-300 hydrogen generator, the sample size is set to 0.6μl, the workstation is N2000, and the temperature rising program is set to 100℃ for 2min, rising to 140℃ at a rate of 20℃ / min for 3min, rising to 160℃ at a rate of 5℃ / min for 2min, and rising to 235℃ at a rate of 20℃ / min for 18min.

[0022] Further, in the above-mentioned method for controlling the explosion limit of the preparation of ε-caprolactone from cyclohexanone, the incondensable gas in the 13th stream mainly comprises nitrogen, oxygen and cyclohexanone; the light component in the 14th stream mainly comprises cyclohexanone, methyl benzoate, benzaldehyde and ε-caprolactone; the heavy component in the 15th stream mainly comprises benzoic acid, 2-benzal cyclohexanone and 6-hydroxy hexanoic acid; the light component in the 17th stream mainly comprises cyclohexanone, methyl benzoate and benzaldehyde; and the heavy component in the 18th stream mainly comprises ε-caprolactone.

[0023] Further, in the above-mentioned method for controlling the explosion limit of the preparation of ε-caprolactone from cyclohexanone, the explosion limit calculation formula of each gas phase stream is as follows:

[0024]

[0025] Lm - Explosion limits of the explosive mixture (%);

[0026] L1, L2, L3, Ln - Explosion limits of the components of the mixture (%);

[0027] V1, V2, V3,... Vn - Concentration of the components in the mixture (%). V1+V2+V3+...Vn = 100; n - Concentration of the components in the mixture (%). V1+V2+V3+...Vn = 100;

[0028] L f - Explosion limits of the mixture containing inert gas (%);

[0029] B - Content of inert gas (%).

[0030] Further, in the above-mentioned intrinsic safety explosion limit control method for preparing ε-caprolactone from cyclohexanone, the lower explosion limit of cyclohexanone is 1.1 / %, the upper explosion limit is 9.4 / %; the lower explosion limit of benzaldehyde is 1.5 / %, the upper explosion limit is 8.4 / %; the lower explosion limit of methyl benzoate is 1.2 / %, the upper explosion limit is 6.7 / %; the lower explosion limit of caprolactone is 1.2 / %, the upper explosion limit is 9 / %; the lower explosion limit of 2-benzylidene cyclohexanone is 1.6 / %, the upper explosion limit is 7.3 / %; the lower explosion limit of isobutyl formate is 2 / %, the upper explosion limit is 8 / %; the lower explosion limit of 6-hydroxyhexanoic acid is 1.3 / %, the upper explosion limit is 8.4 / %; the lower explosion limit of 2,6-dibenzylidene cyclohexanone is 1.2 / %, the upper explosion limit is 8 / %.

[0031] Further, in the above-mentioned intrinsic safety explosion limit control method for preparing ε-caprolactone from cyclohexanone, the upper explosion limit of the 8th stream is

[0032] 8.62L 上 / %, the lower explosion limit is 1.28L 下 / %; the upper explosion limit of the 9th stream is 8.71L 上 / %, the lower explosion limit is 1.28L 下 / %; the upper explosion limit of the 10th stream is 4.89L 上 / %, the lower explosion limit is 0.69L 下 / %; the upper explosion limit of the 12th stream is 8.73L 上 / %, the lower explosion limit is 1.25L 下 / %; the upper explosion limit of the 13th stream is 8.77L 上 / %, the lower explosion limit is 1.23L 下 / %.

[0033] Further, the above-mentioned method for controlling the explosion limit of cyclohexanone preparation of ε-caprolactone is intrinsically safe, the software Aspen Plus is a large chemical simulation software, and a suitable property model NRTL is explored through cyclohexanone and ε-caprolactone binary gas-liquid equilibrium experiments.

[0034] Compared with the prior art, the method has the following beneficial effects:

[0035] 1. The method for controlling the explosion limit of cyclohexanone preparation of ε-caprolactone is provided, which provides a solution for the preparation of ε-caprolactone from cyclohexanone in fine chemical industry, and provides a good reference for industrial production. Before the industrial production of ε-caprolactone product, the method for controlling the explosion limit of cyclohexanone preparation of ε-caprolactone can be used to calculate the air feed amount, so that the mixed gas explosion limit in the gas phase stream of the whole system is within a safe range.

[0036] 3. The process flow of cyclohexanone preparation of ε-caprolactone provided by the application is green and environmentally friendly, and no three wastes are generated. The micro-interface reactor has high reaction efficiency, good airtightness and safety and reliability. The reaction and separation process is simulated and analyzed by using the large chemical simulation software Aspen Plus, so that the component change of each stream can be clearly known. The gas phase stream in the system is simulated and calculated by using the mixed gas explosion limit calculation method, and then whether the air intake amount is within the safe control range is fed back according to the calculation result.

[0037] In summary, the technical scheme provided by the application provides the intrinsic safety guarantee applied to industrial production of ε-caprolactone. The method combines the simulation of modern industrial production by using Aspen Plus and the control of mixed combustible gas explosion limit in industrial production, solves the intrinsic safety of the pipeline in the industrial production process, and provides technical guidance for realizing industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 The process flowchart provided by the application is shown in the figure. DETAILED DESCRIPTION

[0039] The preferred embodiments of the application are described in detail below, so that the advantages and features of the application can be more easily understood by those skilled in the art, and the protection scope of the application is more clearly defined.

[0040] The % content not limited in detail in the application is volume percent.

[0041] The purpose of the application is achieved by the following scheme:

[0042] A method for controlling the explosion limit of cyclohexanone preparation of ε-caprolactone,

[0043] 1) adding cyclohexanone, benzaldehyde, a metalloporphyrin catalyst, and a solvent into a high-pressure reactor, and reacting at 0.5-4 MPa and 50-70° C. to obtain a gas-liquid mixed reaction liquid;

[0044] 2) Enter the names of the chemicals used before and after the reaction into Aspen Plus chemical simulation software, select the NRTL physical property model based on the binary vapor-liquid equilibrium of cyclohexanone and ε-caprolactone, determine the pure components and binary parameters, establish a cyclohexanone and ε-caprolactone reaction and separation process, run the model, and analyze the stream data;

[0045] The NRTL is an activity coefficient model.

[0046] 3) Calculate the explosion limits of the mixed combustible gas in each stream based on the Richard-Chartry explosion limit formula based on the various substances and their contents in the stream; and determine the air feed rate by comparing and feeding back the calculated explosion limit results for each gas phase stream.

[0047] Furthermore, in the above-mentioned intrinsically safe explosion limit control method for preparing ε-caprolactone from cyclohexanone, the mass ratio of cyclohexanone to benzaldehyde is 1-2:2-3.

[0048] Step 1) The specific method is:

[0049] 1) cyclohexanone is mixed in a mixing tank through a first stream, benzaldehyde is mixed in a second stream, and a metalloporphyrin catalyst and a solvent are mixed in a third stream;

[0050] 2) Opening the gas valve of the microchannel reactor, setting the air flow rate of the fourth stream to 20 mL / min, and setting the temperature on the circulation device to 50-70°C; after the temperature in the microchannel reactor reaches the set value, adjusting the air flow rate of the fourth stream to 70 mL / min, then opening the liquid valve, and pumping the mixed solution of cyclohexanone, benzaldehyde, metalloporphyrin catalyst, and solvent into the reactor through the sixth stream at a rate of 5 mL / min for 5 minutes;

[0051] 3) Purge the interior of the microchannel reactor with the fourth high-pressure air stream for 5 minutes;

[0052] 4) After the purge is completed, the air flow rate of the fourth stream is adjusted to 85 mL / min, and then the liquid valve is opened, and the mixed liquid is pumped into the reactor through the sixth stream at a rate of 7 mL / min;

[0053] 5) The reaction liquid of the 8th stream is cooled through a heat exchanger and then enters the 9th stream. The reaction liquid in the 9th stream is passed into a three-necked flask. One branch of the three-necked flask is exhausted through the 10th stream, and the other branch is used to collect the product through the 11th stream.

[0054] Step two) the cyclohexanone, ε-caprolactone reaction separation process flow, see Figure 1 Specifically as follows: the 11th stream collects the product into the 12th stream through a pressure reducing valve, the product in the 12th stream is separated by rectification through a rectification deacidification tower, the incondensable gas enters the 13th stream, the light component enters the 14th stream, and the heavy component enters the 15th stream; the light component in the 14th stream enters the 16th stream through a pump, the components in the 16th stream are separated by rectification through a rectification light removal tower, the light component enters the 17th stream, and the heavy component enters the 18th stream; the light component in the 17th stream enters the 19th stream through a pump, and the light component in the 19th stream is recycled back to the mixing tank.

[0055] The analysis method of each substance in the stream is as follows: a gas chromatography column HT-FFAP is selected, the column volume is 30m x 0.25mm x 0.25μm, the column temperature is 20℃-240℃; the vaporization chamber temperature is set to 240℃; the detection chamber temperature is set to 240℃; the carrier gas is 99.999% high-purity nitrogen; the split ratio is set to 30:1; the air is a GA-2009 air generator; the hydrogen is a HF-300 hydrogen generator; the sample size is set to 0.6μl; the workstation is N2000; the temperature rising program is set to 100℃ for 2min, rising to 140℃ at 20℃ / min, holding for 3min; rising to 160℃ at 5℃ / min, holding for 2min; rising to 235℃ at 20℃ / min, holding for 18min.

[0056] The explosion limit calculation formula of the explosion limit calculation of each gas phase stream is as follows:

[0057]

[0058] L m The explosion limit of the explosive mixture (%);

[0059] L1, L2, L3, Ln - the explosion limit of each component of the mixed gas (%);

[0060] V1, V2, V3, … V n The concentration of each component in the mixed gas (%) V1+V2+V3+…Vn=100;

[0061] L f The explosion limit of the mixed gas containing inert gas (%);

[0062] B - the content of inert gas (%).

[0063] Preparation of ε-caprolactone intrinsic safety explosion limit control method, the software Aspen Plus is a large chemical simulation software, with rich property database, through cyclohexanone, ε-caprolactone binary liquid-liquid equilibrium experiment, explore the appropriate property model NRTL.

[0064] Its cyclohexanone preparation of ε-caprolactone process reaction, separation process chart, see Figure 1 , combined with the data of Aspen Plus software simulation, the process only 8, 9, 10, 12, 13 stream contains gas phase composition, so the gas phase composition in the five streams are calculated.

[0065] The gas components contained in each stream and its content, the following table is the content of each component in each gas phase stream:

[0066] Table 1. the composition of stream 8

[0067]

[0068] Table 2. the composition of stream 9

[0069]

[0070] Table 3. the composition of stream 10

[0071]

[0072] Table 4. the composition of stream 12

[0073]

[0074] Table 5. the composition of stream 13

[0075]

[0076] The upper explosive limit, lower explosive limit of each substance in each gas component

[0077] Table 6. the explosion limit of each pure component

[0078]

[0079] Table 7. the explosion limit of each stream mixed gas

[0080]

[0081] Example 1

[0082] With the example of 400 tons / year of ε-caprolactone chemical simulation process, through the large chemical simulation software Aspen Plus to model, optimize and export the molar fraction of each material in each gas phase stream of the process of preparing ε-caprolactone from cyclohexanone. The feed amount of cyclohexanone, benzaldehyde and solvent is about 140 kg / hr, 300 kg / hr and 250 kg / hr respectively, and the main product cyclohexanone is about 400 t / year and the by-product benzoic acid is about 490 t / year. By querying the chemical handbook and the online explosion limit of single component material, i.e. the upper explosion limit and the lower explosion limit. According to the Le Chatelier explosion limit formula, the multi-component explosion limit of the gas phase stream is calculated. Through the calculation results, it is fed back whether the air intake amount is reasonable and whether it meets the lower limit of the mixed gas in the gas phase stream after the reaction. If it does not meet, the air intake amount in the system of preparing ε-caprolactone from cyclohexanone needs to be adjusted, and the simulation results are calculated again. In this way, a suitable air intake amount can be finally obtained. Through the analysis of the process stream, it is known that there are 5 gas phase streams in the process, and through the calculation, the explosion limit of the inert gas mixed gas in each gas phase stream is 10.38%~45.81%, 11.33%~48.54%, 6.31%~33.33%, 11.91%~50.44% and 5.91%~32.60% respectively. And by comparing the content of each component in each gas phase stream, the intrinsic safety of each stream is verified, and finally the reasonable value of the calculated air intake amount is 35 kg / hr.

[0083] Example 2

[0084] Take the example of 400 tons / year of cyclohexene epoxide chemical simulation process, through the large chemical simulation software Aspen Plus on cyclohexene preparation process modeling, optimization and export of each gas phase stream of each substance molar fraction. Cyclohexene, isobutyraldehyde, solvent feed rate is about 204 kg / hr, 65 kg / hr, 50 kg / hr, the main product cyclohexene epoxide is about 400 tons / year, by-product isobutyric acid is about 616 t / year. By querying the chemical handbook and online single component material explosion limit, that is, the upper explosive limit and the lower explosive limit. According to the Rietzler explosion limit formula, the multi-component explosion limit of gas phase stream is calculated. Through the calculation results, feedback whether the air intake is reasonable, whether it meets the mixed gas in the gas phase stream after the reaction in the lower limit of the explosion limit, if not, the air intake of cyclohexene preparation cyclohexene epoxide system needs to be adjusted, and the simulation results are calculated again. Through the process stream analysis, it can be known that the process exists 7 gas phase streams, and through the calculation, the inert gas mixed gas explosion limit of each gas phase stream is 13.91%~49.54%, 17.46%~56.15%, 8.22%~35.2%, 17.46%~56.15%, 10.33%~41.0%, 13.72%~49.05, 17.46%~56.15%. And compare the content of each component in each gas phase stream to verify the intrinsic safety of each stream, and finally feedback the reasonable value of the calculated air intake is 605 kg / hr.

[0085] Example 3

[0086] Taking the simulation process of 400 tons / year of benzoic acid as an example, the process of preparing benzoic acid from toluene was modeled, optimized and the mole fraction of each substance in each gas stream was exported by using large chemical simulation software Aspen Plus. The toluene, 420 kg / hr, the main product benzoic acid is about 400 tons / year, the by-products benzaldehyde and benzyl alcohol are about 424 t / year and 184 t / year respectively. By querying the chemical handbook and the online explosion limit of single component substance, the upper and lower explosion limits are obtained. According to the Le Chatelier explosion limit formula, the multi-component explosion limit of gas stream is calculated. Through the calculation results, it is feedback whether the air intake is reasonable and whether it meets the lower limit of the mixed gas in the gas stream after the reaction. If not, the air intake of the toluene preparation benzoic acid system needs to be adjusted, and the simulation results need to be calculated again. Through the process stream analysis, it is known that there are two gas streams in the process, and the inert gas mixed gas explosion limit of each gas stream can be calculated as 2.95%~15.96% and 5.54%~28.68% respectively. And by comparing the content of each component in each gas stream, the intrinsic safety of each stream is verified, and the reasonable value of the calculated air intake is 104 kg / hr.

Claims

1. A method for controlling the explosion limit of cyclohexanone in the preparation of ε-caprolactone, characterized in that, I) cyclohexanone, benzaldehyde, metal porphyrin catalyst and solvent are added to a high-pressure reactor, and a gas-liquid mixed reaction liquid is obtained at 0.5-4 MPa and 50-70℃; II) the chemical names used before and after the reaction are input into the Aspen Plus chemical simulation software, and the NRTL property model is selected based on the cyclohexanone and ε-caprolactone binary gas-liquid equilibrium to determine the pure components and binary parameters, establish the cyclohexanone and ε-caprolactone reaction separation process, run the model and analyze the stream data; III) based on the Le Chatelier explosion limit formula, the explosion limit of the mixed combustible gas in each stream is calculated according to the substances and their contents in the stream; the air feed amount is determined by comparing and feeding back the calculation results of the explosion limit of each gas stream. The specific method of step I) is as follows: Cyclohexanone is pumped into the first stream, benzaldehyde is pumped into the second stream, and metal porphyrin catalyst and solvent are pumped into the third stream in a mixing tank; Open the gas path valve of the microchannel reactor, set the air flow rate of the fourth stream to 20 mL / min, and set the temperature on the circulating device to 50-70℃; after the temperature in the microchannel reactor reaches the set value, adjust the air flow rate of the fourth stream to 70 mL / min, then open the liquid path valve, and pump the mixed liquid of cyclohexanone, benzaldehyde, metal porphyrin catalyst and solvent into the reactor through the sixth stream at a speed of 5 mL / min for 5 min; Purge the inside of the microchannel reactor with high-pressure gas through the fourth stream for 5 min; After the purge is completed, adjust the air flow rate of the fourth stream to 85 mL / min, then open the liquid path valve, and pump the mixed liquid into the reactor through the sixth stream at a speed of 7 mL / min; The reaction liquid in the eighth stream is cooled by a heat exchanger and then enters the ninth stream, the reaction liquid in the ninth stream is introduced into a three-necked flask, one branch of the three-necked flask is exhausted through the tenth stream, and the other branch collects the product through the eleventh stream; The product collected in the eleventh stream is introduced into the twelfth stream through a pressure reducing valve, the product in the twelfth stream is separated by rectification through a rectification and deacidification tower, non-condensable gas is introduced into the thirteenth stream, light components are introduced into the fourteenth stream, and heavy components are introduced into the fifteenth stream; the light components in the fourteenth stream are pumped into the sixteenth stream, the components in the sixteenth stream are separated by rectification through a rectification and light component removal tower, light components are introduced into the seventeenth stream, heavy components are introduced into the eighteenth stream, the light components in the seventeenth stream are pumped into the nineteenth stream, and the light components in the nineteenth stream are recycled back to the mixing tank. The mass ratio of cyclohexanone to benzaldehyde is 1-2:2-3. The solvent is one of n-butane, cyclohexane, acetonitrile, methyl benzoate and toluene.

2. The method according to claim 1, wherein the method is a method for controlling the explosion limit of cyclohexanone for preparing ε-caprolactone, characterized by, ​ 3. The method according to claim 1, wherein the method is a method for controlling the explosion limit of cyclohexanone for preparing ε-caprolactone, characterized by, ​ 4. The method according to claim 1, wherein the method is a method for controlling the explosion limit of cyclohexanone for preparing ε-caprolactone, characterized by, The analysis method of the flow data is as follows: the gas chromatographic column HT-FFAP is selected, the column volume is 30 m*0.25 mm*0.25 μm, the column temperature is 20-240 DEG C; the vaporization chamber temperature is set to 240 DEG C; the detection chamber temperature is set to 240 DEG C; the carrier gas is 99.999% high-purity nitrogen; the split ratio is set to 30:1; the air is GA-2009 air generator; the hydrogen is HF-300 hydrogen generator; the sample injection volume is set to 0.6 μl; the workstation is N2000; the temperature rising program is set to 100 DEG C for 2 min, rising to 140 DEG C at a rate of 20 DEG C / min, keeping for 3 min, rising to 160 DEG C at a rate of 5 DEG C / min, keeping for 2 min, and rising to 235 DEG C at a rate of 20 DEG C / min, keeping for 18 min.

5. The method according to claim 4, wherein the method is a method for controlling the explosion limit of cyclohexanone for preparing ε-caprolactone, characterized by, The non-condensable gas in the 13th flow is mainly nitrogen, oxygen and cyclohexanone; the light components in the 14th flow are mainly cyclohexanone, methyl benzoate, benzaldehyde and epsilon-caprolactone; the heavy components in the 15th flow are mainly benzoic acid, 2-benzal cyclohexanone and 6-hydroxyhexanoic acid; the light components in the 17th flow are mainly cyclohexanone, methyl benzoate and benzaldehyde; and the heavy components in the 18th flow are mainly epsilon-caprolactone.

6. The method according to claim 1, wherein the method is a method for controlling the explosion limit of cyclohexanone for preparing ε-caprolactone, characterized by, The explosion limit calculation formula for calculating the explosion limit of each gas phase flow is as follows: ； L m - the explosion limits of the explosive mixture; L1, L2, L3, Ln - explosion limit of each component of the mixed gas%; V1, V2, V3,..., V n - Concentration of each component in the mixture gas; V1+ V2+ V3+……+Vn =100; L f - is the explosion limit of the inert gas mixture; B - content of inert gas%.

7. The method according to claim 6, wherein the method is a method for controlling the explosion limit of cyclohexanone for preparing ε-caprolactone, characterized by, The lower explosion limit of cyclohexanone is 1.1%, the upper explosion limit is 9.4%; the lower explosion limit of benzaldehyde is 1.5%, the upper explosion limit is 8.4%; the lower explosion limit of methyl benzoate is 1.2%, the upper explosion limit is 6.7%; the lower explosion limit of caprolactone is 1.2%, the upper explosion limit is 9%; the lower explosion limit of 2-benzal cyclohexanone is 1.6%, the upper explosion limit is 7.3%; the lower explosion limit of isobutyl formate is 2%, the upper explosion limit is 8%; the lower explosion limit of 6-hydroxyhexanoic acid is 1.3%, the upper explosion limit is 8.4%; the lower explosion limit of 2,6-benzal cyclohexanone is 1.2%, the upper explosion limit is 8%.

8. The method according to claim 7, wherein the method is a method for controlling the explosion limit of cyclohexanone for preparing ε-caprolactone, characterized by, Explosive upper limit of 8.62 L 上 Explosive lower limit of 1.28 L 下 Explosive upper limit of 8.71 L 上 Explosive lower limit of 1.28 L 下 Explosive upper limit of 4.89 L 上 Explosive lower limit of 0.69 L 下 Explosive upper limit of 8.73 L 上 Explosive lower limit of 1.25 L 下 Explosive upper limit of 8.77 L 上 Explosive lower limit of 1.23 L 下 .

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