Method for cracking and refining recovery of butanol octanol residual liquid

Abstract

This invention discloses a method for cracking and refining butanol and octanol residue: the cracking agent cracks C12 and C16 in the residue into C4 and C8 components, which are then distilled and condensed before being sent to distillation column #1 for further distillation; the C4 and lower components at the top of distillation column #1 are condensed and sent to distillation column #2 for further distillation, while the C4 and higher components at the bottom are sent to distillation column #3; the butyraldehyde and trace amounts of water mixed at the top of distillation column #2 are condensed and sent to the butyraldehyde distillation system, while the butanol and water mixed at the bottom are sent to distillation column #4 for further distillation. The top of distillation column #3, containing butyl butyrate, C5-C7 compounds, and trace amounts of water, is condensed and sent to the waste tank of the butanol and octanol unit. The bottom of the column, containing octanol, EPA, EHA, and a small amount of uncracked heavy components, is sent to distillation column #5. The top of distillation column #4, containing water and trace amounts of mixed butanol, is condensed and sent to the water stripping system. The bottom of the column, containing mixed butanol, is sent to the butanol distillation system. The top of distillation column #5, containing crude octanol, is condensed and sent to the octanol distillation system. The bottom of the column, containing uncracked heavy components and a small amount of crude octanol, is sent to the cracking feed tank. The recovery rate of the residual liquid in this invention reaches over 90%.

Description

Technical Field

[0001] This invention relates to organic residue pyrolysis and recovery technology, and more specifically, to a method for pyrolysis and refining of butanol and octanol residues. Background Technology

[0002] Butanol and octanol are important basic organic chemical raw materials widely used in various industrial fields. During their production, a certain amount of residual liquid is inevitably generated. This residual liquid is substantial, accounting for approximately 5% to 10% of the butanol and octanol production, and its composition is complex. Besides a small amount of water, it contains dozens of compounds, including C4-C16 alcohols, aldehydes, alkenes, acetals, acids, and esters, making separation extremely difficult. Directly discharging this residual liquid along with wastewater not only wastes valuable resources but also causes serious environmental pollution.

[0003] The industry has explored various methods for recycling this residual liquid, but existing technologies still have significant shortcomings. Currently, the main treatment method involves directly separating light components such as C4 and C8 from the residual liquid through distillation. However, for the heavy components (C8 and above) that make up 40% to 50% of the residual liquid, existing distillation technologies cannot effectively recover them. This unrecovered portion of the residual liquid is typically sold as fuel. Due to this limitation, the current recovery rate of butanol and octanol residual liquid is generally below 50%, and resource utilization urgently needs improvement.

[0004] To improve this situation, recent studies have attempted to use pyrolysis to first break down recombinant C12 and C16 compounds in the residual liquid into recoverable lighter components such as C4 and C8. Then, distillation is used to recover these lighter components one by one. This approach has significantly improved the recovery rate of the residual liquid. Currently, the main pyrolysis methods available are thermal pyrolysis and catalytic pyrolysis, but both methods have their own technical limitations.

[0005] Specifically, traditional thermal cracking processes require the addition of large amounts of water as a cracking agent, reaching 10% to 20% of the residual liquid mass, and the reaction must be carried out at temperatures above 600°C. This process not only consumes a lot of energy but also generates a large amount of wastewater during cracking, resulting in high costs for subsequent wastewater treatment and a high risk of secondary pollution. While catalytic cracking processes do not require high temperatures and can be carried out at lower temperatures of 200°C to 250°C, they require expensive catalysts such as metals, metal salts, and molecular sieves. The preparation of these catalysts is complex and requires high-temperature calcination, resulting in overall high energy consumption and poor economic efficiency for catalytic cracking processes.

[0006] In summary, existing technologies for recovering butanol and octanol residues either suffer from low recovery rates and significant resource waste, or they present problems such as high energy consumption, high costs, and the risk of secondary pollution, making it difficult to meet the dual demands of resource recycling and environmental emission reduction in the current chemical industry. Therefore, developing a method that can overcome the aforementioned shortcomings of existing technologies and achieve efficient, low-consumption, and high-value recovery of butanol and octanol residues has become a pressing technical challenge for the butanol and octanol production industry, possessing significant practical importance and application value. Summary of the Invention

[0007] To overcome the shortcomings of existing technologies, this invention proposes a method for cracking and refining butanol and octanol residues. This method uses a special cracking agent that is inexpensive, easy to prepare, and operates under mild conditions to decompose the C12 and C16 components in the butanol and octanol residues into lighter components such as C4 and C8. The residues are then refined and recovered through a 5-tower distillation process, achieving a recovery rate of over 90%. This method effectively utilizes the residues and transforms waste into valuable resources.

[0008] The objective of this invention can be achieved through the following technical solutions.

[0009] A method for cracking and purifying butanol residue for recovery includes the following steps: Step 1: The butanol and octanol residue from the feedstock tank is transferred to the pyrolysis distillation kettle. Simultaneously, the pyrolysis agent from the pyrolysis agent tank is transferred to the pyrolysis distillation kettle. The pyrolysis agent reacts with the C12 and C16 components in the butanol and octanol residue, pyrolyzing them into C4 and C8 components. These components, along with the original C4-C8 components in the butanol and octanol residue, are distilled to the top of the pyrolysis distillation kettle. After being condensed by the pyrolysis distillation kettle condenser, they flow into the pyrolysis distillation kettle condenser. The condensate is output in two streams: one stream returns to the pyrolysis distillation kettle as reflux, and the other stream goes to the No. 1 distillation column as its feed. Periodically, a portion of the kettle liquid is discharged to the butanol and octanol unit waste liquid tank via the bottom pump of the pyrolysis distillation kettle. Step 2: The material entering distillation column #1 is separated by distillation. The top material, consisting of C4 and lower components, is condensed in the condenser of distillation column #1 and flows into the condenser tank of distillation column #1. The condensate is output in two streams: one stream returns to distillation column #1 as reflux, and the other stream goes to distillation column #2 as its feed. The wastewater in the condenser tank of distillation column #1 is sent to the water stripping system of the butanol and octanol unit to recover the organic phase. The bottom material of distillation column #1, consisting of components with C4 and above, is transported to distillation column #3 as its feed. Step 3: The material entering the No. 2 distillation column is separated by distillation. The top material is a mixture of butyraldehyde and trace amounts of water. After being condensed in the condenser of the No. 2 distillation column, it flows into the condenser tank of the No. 2 distillation column. The condensate is output in two streams: one stream is returned to the No. 2 distillation column as reflux, and the other stream, containing the mixed butyraldehyde, is sent to the butyraldehyde distillation system of the butanol and octanol unit for recovery. The wastewater in the condenser tank of the No. 2 distillation column is sent to the water stripping system of the butanol and octanol unit to recover the organic phase. The bottom material of the No. 2 distillation column is a mixture of butanol and water, which is sent to the No. 4 distillation column as its feed. Step 4: The material entering the No. 3 distillation column is separated by distillation. The top material is butyl butyrate, C5-C7 compounds, and a trace amount of water. After being condensed in the No. 3 distillation column condenser, it flows into the No. 3 distillation column condenser tank. The condensate is output in two streams: one stream is returned to the No. 3 distillation column as reflux, and the other stream, which contains intermediate components, is sent to the waste liquid tank of the butanol and octanol unit for periodic external sale. The wastewater in the condenser tank of the No. 3 distillation column is pumped to the water stripping system of the butanol and octanol unit to recover the organic phase. The bottom material of the No. 3 distillation column is octanol, EPA, EHA, and a small amount of uncracked heavy components, which is sent to the No. 5 distillation column as its feed. Step 5: The material entering the No. 4 distillation column is separated by distillation. The top material is water and a trace amount of mixed butanol. After being condensed by the condenser of the No. 4 distillation column, it flows into the condenser tank of the No. 4 distillation column. The condensate is output in two streams: one stream is returned to the No. 4 distillation column as reflux, and the other stream goes to the water stripping system of the butanol and octanol unit to recover the organic phase. The bottom material of the No. 4 distillation column is mixed butanol. The mixed butanol is collected by the bottom pump of the No. 4 distillation column and sent to the butanol distillation system of the butanol and octanol unit for recovery. Step 6: The material entering the No. 5 distillation column is separated by distillation. The top material is crude octanol, which is condensed by the No. 5 distillation column condenser and flows into the No. 5 distillation column condenser tank. The condensate is output in two streams: one stream is returned to the No. 5 distillation column as reflux, and the other stream is taken out as crude octanol and sent to the octanol distillation system of the butanol and octanol unit for recovery. The bottom material of the No. 5 distillation column is uncracked heavy components and a small amount of crude octanol, which is sent to the cracking feed tank for recycling.

[0010] Further, in the first step, the flow rate of the butanol and octanol residue in the pyrolysis feed tank into the pyrolysis distillation vessel is 2-4 t / h. The pyrolysis agent is an alkaline mixed liquid with the following mass composition: sodium hydroxide 18%-34%, potassium hydroxide 12%-26%, water 35%-55%, ethylene glycol 2%-6%, ethanol 0.4%-1.2%, potassium permanganate 1%-2%, barium hydroxide 0.1%-0.3%, and sodium tetraborate 0.5%-1.5%. The amount of the pyrolysis agent used is 0.1%-0.5% of the mass of the butanol and octanol residue. The bottom pump of the pyrolysis distillation vessel discharges a portion of the vessel liquid every 6-10 hours, with a discharge amount of 5%-8% of the vessel liquid mass. The operating pressure of the pyrolysis distillation vessel is -80 kPa to -50 kPa, the bottom temperature is 200℃-240℃, the top temperature is 140℃-170℃, and the reflux ratio is 0.08-0.1.

[0011] Furthermore, in the second step, the operating pressure of the No. 1 distillation column is -100KPa to -60KPa, the bottom temperature is 155℃ to 175℃, the top temperature is 122℃ to 144℃, and the reflux ratio is 2 to 4.

[0012] Furthermore, in the third step, the operating pressure of the No. 2 distillation column is -30KPa to -10KPa, the bottom temperature is 133℃ to 155℃, the top temperature is 93℃ to 111℃, and the reflux ratio is 1.5 to 5.5.

[0013] Furthermore, the operating pressure of the No. 3 distillation column described in step four is -50KPa to -30KPa, the bottom temperature is 168℃ to 184℃, the top temperature is 150℃ to 170℃, and the reflux ratio is 3 to 7.

[0014] Furthermore, the operating pressure of the No. 4 distillation column described in step 5 is -150KPa to -100KPa, the bottom temperature is 115℃ to 125℃, the top temperature is 94℃ to 108℃, and the reflux ratio is 4 to 8.

[0015] Furthermore, the operating pressure of the No. 5 distillation column described in step six is ​​-70KPa to -30KPa, the bottom temperature is 178℃ to 196℃, the top temperature is 164℃ to 178℃, and the reflux ratio is 3.5 to 7.5.

[0016] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows: (1) By optimizing the cracking process and refining separation process, this invention can efficiently crack the heavy components (such as C12, C16, etc.) accounting for 40%~50% of the butanol and octanol residue into light components with high economic value such as C4 and C8. Then, the mixture of butyraldehyde (n-butyraldehyde, isobutyraldehyde), mixture of butanol (n-butanol, isobutanol), crude octanol (octanol, EPA, EHA) and other components in the cracking residue can be recovered. This invention overcomes the defect of traditional distillation technology that cannot recover heavy components, and increases the overall recovery rate of butanol and octanol residue from the current general level of less than 50% to more than 90%. This invention achieves the goal of making full use of butanol and octanol residue waste and turning waste into treasure, greatly reducing resource waste and transforming the heavy components that could only be sold as cheap fuel into high-value chemical raw materials, thus significantly improving the economic benefits of enterprises.

[0017] (2) The amount of pyrolysis agent used in this invention is very small, accounting for only 0.1% to 0.5% of the mass of butanol and octanol residue. At the same time, the pyrolysis conditions have been optimized, and the heavy components in butanol and octanol residue can be efficiently pyrolyzed at a relatively low temperature (200℃ to 240℃). Compared with traditional thermal pyrolysis (using only water as the pyrolysis agent, the amount of water added is 10% to 20% of the mass of the residue, and the pyrolysis temperature is above 600℃), the amount of water added is reduced by more than 50%, which greatly reduces the generation of wastewater and significantly reduces energy consumption.

[0018] (3) The cracking agent in this invention is inexpensive and easy to make. Compared with the metal, metal oxide, molecular sieve and other catalysts used in traditional catalytic cracking processes, it saves costs and eliminates the cumbersome catalyst preparation process (the general process includes the preparation of precursor solution, impregnation of carrier, drying, washing and calcination). It significantly improves the economic efficiency and industrial feasibility of the process.

[0019] (4) Through precise refining and separation processes, this invention can effectively control the impurity content in the pyrolysis products, avoiding the environmental pollution problems caused by the large amount of wastewater discharge in traditional pyrolysis. This invention realizes the recycling of most components in the residual liquid, significantly reducing the amount of residual liquid that needs to be sold for incineration, reducing the emission risks of waste gas and waste residue during incineration, meeting the requirements of current environmental protection and emission reduction policies, and possessing good environmental friendliness.

[0020] (5) The present invention optimizes the synergistic process parameters of cracking and refining, which can effectively avoid the equipment blockage problem caused by high-temperature coking of heavy components in the existing distillation technology, reduce equipment maintenance costs and the probability of unplanned shutdowns; at the same time, the present invention has good adaptability to butanol and octanol residues of different components and concentrations, without the need to adjust the core process for the residue components, making it easy to upgrade existing butanol and octanol production units, and has broad application prospects. Attached Figure Description

[0021] Figure 1This is a schematic diagram of the process flow for the cracking, refining, and recovery of butanol and octanol residues according to the present invention.

[0022] Figure reference numerals: 1-Pyrolysis agent tank, 2-Pyrolysis agent feed pump, 3-Pyrolysis distillation kettle, 4-Pyrolysis distillation kettle condenser, 5-Pyrolysis distillation kettle condenser, 6-Pyrolysis distillation kettle reflux pump, 7-Pyrolysis distillation kettle reboiler, 8-Pyrolysis distillation kettle bottom pump, 9-Pyrolysis feed pump, 10-Pyrolysis feed tank, 11-#1 distillation column, 12-#1 distillation column condenser, 13-#1 distillation column condenser, 14-#1 distillation column reflux pump, 15-#1 distillation column wastewater pump, 16-#1 distillation column reboiler, 17-#1 distillation column bottom pump, 18-#2 distillation column, 19-#2 distillation column condenser, 20-#2 distillation column condenser, 21-#2 distillation column reflux pump, 22-#2 distillation column wastewater pump 23-2# distillation column reboiler, 24-2# distillation column bottom pump, 25-3# distillation column, 26-3# distillation column condenser, 27-3# distillation column condenser tank, 28-3# distillation column reflux pump, 29-3# distillation column wastewater pump, 30-3# distillation column reboiler, 31-3# distillation column bottom pump, 32-4# distillation column, 33-4# distillation column condenser, 34-4# distillation column condenser tank, 35-4# distillation column reflux pump, 36-4# distillation column reboiler, 37-4# distillation column bottom pump, 38-5# distillation column, 39-5# distillation column condenser, 40-5# distillation column condenser tank, 41-5# distillation column reflux pump, 42-5# distillation column reboiler, 43-5# distillation column bottom pump. Detailed Implementation

[0023] The present invention will now be further described with reference to the accompanying drawings.

[0024] The process flow of the method for cracking and refining the butanol and octanol residue of the present invention is as follows: Figure 1As shown, the main components include: 1. Cracking agent tank; 2. Cracking agent feed pump; 3. Cracking distillation kettle; 4. Cracking distillation kettle condenser; 5. Cracking distillation kettle reflux pump; 6. Cracking distillation kettle reboiler; 7. Cracking distillation kettle bottom pump; 8. Cracking feed pump; 9. Cracking feed tank; 10. No. 1 distillation column; 11. No. 1 distillation column condenser; 12. No. 1 distillation column condenser; 13. No. 1 distillation column reflux pump; 14. No. 1 distillation column wastewater pump; 15. No. 1 distillation column reboiler; 16. No. 1 distillation column bottom pump; 17. No. 2 distillation column; 18. No. 2 distillation column condenser; 19. No. 2 distillation column condenser; 20. No. 2 distillation column reflux pump; 21. No. 2 distillation column wastewater pump; 22. No. 2 distillation column bottom pump; 23. No. 2 distillation column bottom pump; 4. No. 1 distillation column condenser; 5. No. 1 distillation column reflux pump; 6. No. 1 distillation column reboiler; 7. No. 1 distillation column bottom pump; 8. No. 1 distillation column bottom pump; 19. No. 1 distillation column condenser; 20. No. 2 distillation column reflux pump; 21. No. 2 distillation column wastewater pump; 22. No. 2 distillation column bottom pump; 23. No. 2 distillation column bottom pump; 24. No. 1 distillation column reflux pump; 25. No. 1 distillation column bottom pump; 26 The following components are included: reboiler 23, bottom pump 24 of distillation column #2, bottom pump 25 of distillation column #3, condenser 26 of distillation column #3, condenser tank 27 of distillation column #3, reflux pump 28 of distillation column #3, wastewater pump 29 of distillation column #3, reboiler 30 of distillation column #3, bottom pump 31 of distillation column #3, bottom pump 32 of distillation column #4, condenser 33 of distillation column #4, condenser tank 34 of distillation column #4, reflux pump 35 of distillation column #4, reboiler 36 of distillation column #4, bottom pump 37 of distillation column #5, bottom pump 48 of distillation column #5, condenser 39 of distillation column #5, condenser tank 40 of distillation column #5, reflux pump 41 of distillation column #5, reboiler 42 of distillation column #5, bottom pump 43 of distillation column #5, and related connecting pipelines.

[0025] In the above process flow, the cracking agent inlet of the cracking distillation kettle 3 is connected to the cracking agent tank 1 via a pipeline through the cracking agent feed pump 2. The raw material inlet of the cracking distillation kettle 3 is connected to the cracking raw material tank 10 via a pipeline through the cracking raw material feed pump 9. The bottom outlet of the cracking distillation kettle 3 is connected to the waste liquid tank of the butanol and octanol unit via a discharge pipeline through the bottom pump 8. A cracking distillation kettle reboiler 7 is installed at the bottom of the cracking distillation kettle 3. The top outlet of the cracking distillation kettle 3 is connected to the distillation kettle condenser 4 and the cracking distillation kettle condenser 5 in sequence via pipelines. The outlet of the cracking distillation kettle condenser 5 is connected to the inlet of the cracking distillation kettle reflux pump 6 via a pipeline. The outlet of the cracking distillation kettle reflux pump 6 is divided into two paths: one path is connected to the upper reflux port of the cracking distillation kettle 3 via a pipeline, and the other path is connected to the inlet of the No. 1 distillation column 11 via a pipeline.

[0026] In the above process flow, the bottom outlet of the No. 1 distillation column 11 is connected to the inlet of the No. 3 distillation column 25 via a pipeline through the No. 1 distillation column bottom pump 17. The reboiler 16 of the No. 1 distillation column 11 is installed in the bottom of the column. The top outlet of the No. 1 distillation column 11 is connected to the No. 1 distillation column condenser 12 and the No. 1 distillation column condenser tank 13 in sequence via pipelines. The wastewater outlet of the No. 1 distillation column condenser tank 13 is connected to the water stripping system of the butanol and octanol unit via a discharge pipeline through the No. 1 distillation column wastewater pump 15. The reflux outlet of the No. 1 distillation column condenser tank 13 is connected to the inlet of the No. 1 distillation column reflux pump 14 via a pipeline. The outlet of the No. 1 distillation column reflux pump 14 is divided into two paths: one path is connected to the upper reflux port of the No. 1 distillation column 11 via a pipeline, and the other path is connected to the inlet of the No. 2 distillation column 18 via a pipeline.

[0027] In the above process flow, the bottom outlet of the No. 2 distillation column 18 is connected to the inlet of the No. 4 distillation column 32 via a pipeline and the No. 2 distillation column bottom pump 24. The reboiler 23 of the No. 2 distillation column 18 is installed in the bottom of the column. The top outlet of the No. 2 distillation column 18 is connected to the No. 2 distillation column condenser 19 and the No. 2 distillation column condenser tank 20 in sequence via pipelines. The wastewater outlet of the No. 2 distillation column condenser tank 20 is connected to the water stripping system of the butanol and octanol unit via a discharge pipeline and the No. 2 distillation column wastewater pump 22. The reflux outlet of the No. 2 distillation column condenser tank 20 is connected to the inlet of the No. 2 distillation column reflux pump 21 via a pipeline. The outlet of the No. 2 distillation column reflux pump 21 is divided into two paths: one path is connected to the upper reflux port of the No. 2 distillation column 18 via a pipeline, and the other path is connected to the butanol and octanol unit butyraldehyde distillation system via a pipeline.

[0028] In the above process flow, the bottom outlet of the No. 3 distillation column 25 is connected to the inlet of the No. 5 distillation column 38 via a pipeline and the bottom pump 31 of the No. 3 distillation column. The reboiler 30 of the No. 3 distillation column 25 is installed in the bottom of the column. The top outlet of the No. 3 distillation column 25 is connected to the No. 3 distillation column condenser 26 and the No. 3 distillation column condenser tank 27 in sequence via pipelines. The wastewater outlet of the No. 3 distillation column condenser tank 27 is connected to the water stripping system of the butanol and octanol unit via a discharge pipeline and the wastewater pump 29 of the No. 3 distillation column. The reflux outlet of the No. 3 distillation column condenser tank 27 is connected to the inlet of the No. 3 distillation column reflux pump 28 via a pipeline. The outlet of the No. 3 distillation column reflux pump 28 is divided into two paths: one path is connected to the upper reflux port of the No. 3 distillation column 25 via a pipeline, and the other path is connected to the waste liquid tank of the butanol and octanol unit via a pipeline.

[0029] In the above process flow, the bottom outlet of the No. 4 distillation column 32 is connected to the butanol distillation system of the butanol and octanol unit via a pipeline and the bottom pump 37 of the No. 4 distillation column. The reboiler 36 of the No. 4 distillation column 32 is installed in the bottom of the column. The top outlet of the No. 4 distillation column 32 is connected to the condenser 33 and the condenser tank 34 of the No. 4 distillation column via pipelines. The outlet of the condenser tank 34 of the No. 4 distillation column is connected to the inlet of the reflux pump 35 of the No. 4 distillation column via a pipeline. The outlet of the reflux pump 35 of the No. 4 distillation column is divided into two paths: one path is connected to the upper reflux port of the No. 4 distillation column 32 via a pipeline, and the other path is connected to the water stripping system of the butanol and octanol unit via a pipeline.

[0030] In the above process flow, the bottom outlet of the No. 5 distillation column 38 is connected to the cracking feed tank 10 via a pipeline through the No. 5 distillation column bottom pump 43. The reboiler 42 of the No. 5 distillation column 38 is installed in the bottom of the column. The top of the No. 5 distillation column 38 is connected in sequence to the No. 5 distillation column condenser 39 and the No. 5 distillation column condenser tank 40 via pipelines. The outlet of the No. 5 distillation column condenser tank 40 is connected to the inlet of the No. 5 distillation column reflux pump 41 via a pipeline. The outlet of the No. 5 distillation column reflux pump 41 is divided into two paths: one path is connected to the upper reflux port of the No. 5 distillation column 38 via a pipeline, and the other path is connected to the octanol distillation system of the butanol and octanol unit via a pipeline.

[0031] In the above process flow, the condenser 13 of the No. 1 distillation column, the condenser 20 of the No. 2 distillation column, and the condenser 27 of the No. 3 distillation column are all equipped with boots. Their function is to separate oil and water. After the aqueous phase is enriched in the boot, it is sent to the water stripping system of the butanol and octanol unit to recover the organic phase through the wastewater pumps 15, 22, and 29 of the No. 1 distillation column, which are respectively set at the bottom.

[0032] The method for cracking and refining butanol residue of the present invention includes the following steps: Step 1: The butanol and octanol residue in the cracking feed tank 10 is pumped to the cracking distillation vessel 3 at a flow rate of 2-4 t / h via the cracking feed feed pump 9. Simultaneously, the cracking agent in the cracking agent tank 1 is transported to the cracking distillation vessel 3 via the cracking agent feed pump 2. The amount of cracking agent is 0.1%-0.5% of the mass of the butanol and octanol residue. A cracking reaction occurs in the cracking distillation vessel 3. The cracking agent reacts with the C12 and C16 components in the butanol and octanol residue, breaking them down into C4 and C8 components. These components, along with the original C4-C8 components in the butanol and octanol residue, are distilled to the top of the cracking distillation vessel 3. After being condensed by the cracking distillation vessel condenser 4, they flow into the cracking distillation vessel condenser tank 5. The condensate in the cracking distillation vessel condenser tank 5 is output in two streams via the cracking distillation vessel reflux pump 6: one stream returns to the cracking distillation vessel 3 as reflux, and the other stream goes to the No. 1 distillation column 11 as its feed. Periodically (every 6-10 hours), discharge a portion of the liquid in the cracking distillation vessel 3 (5%-8% of the liquid mass) to the waste tank of the butanol and octanol unit via the bottom pump 8 to prevent the cracking agent from accumulating in the cracking distillation vessel 3 and causing the liquid to coke.

[0033] The pyrolysis agent is used to break down the C12 and C16 components in the butanol / octanol residue into C4 and C8 light components. The pyrolysis agent is an alkaline mixed liquid with the following mass composition: sodium hydroxide 18%–34%, potassium hydroxide 12%–26%, water 35%–55%, ethylene glycol 2%–6%, ethanol 0.4%–1.2%, potassium permanganate 1%–2%, barium hydroxide 0.1%–0.3%, and sodium tetraborate 0.5%–1.5%.

[0034] The operating pressure of the pyrolysis distillation vessel 3 is -80KPa to -50KPa, the bottom temperature is 200℃ to 240℃, the top temperature is 140℃ to 170℃, and the reflux ratio is 0.08 to 0.1.

[0035] Step 2: The material entering distillation column 11 is separated by distillation. The top material consists of components of C4 and below (water, n-butyraldehyde, isobutyraldehyde, n-butanol, isobutanol, etc.), which are condensed by condenser 12 and flow into condenser 13. The condensate in condenser 13 is split into two streams by reflux pump 14: one stream returns to distillation column 11 as reflux, and the other goes to distillation column 2 as feed. The wastewater in condenser 13 is sent to the steam stripping system of the butanol and octanol unit by wastewater pump 15 to recover the organic phase. The bottom material of distillation column 11 consists of components of C4 and above (C5~C7, butyl butyrate, EPA, EHA, octanol, and a small amount of uncracked heavy components, etc.), which are sent to distillation column 3 as feed by bottom pump 17.

[0036] The operating pressure of the No. 1 distillation column 11 is -100KPa to -60KPa, the bottom temperature is 155℃ to 175℃, the top temperature is 122℃ to 144℃, and the reflux ratio is 2 to 4.

[0037] Step 3: The material entering distillation column 18 is separated by distillation. The top material is a mixture of butyraldehyde (n-butyraldehyde and isobutyraldehyde) and a trace amount of water. After being condensed by condenser 19 of distillation column 18, it flows into condenser tank 20 of distillation column 18. The condensate in condenser tank 20 is split into two streams by reflux pump 21: one stream returns to distillation column 18 as reflux, and the other stream, containing the mixed butyraldehyde, is sent to the butyraldehyde distillation system of the butanol and octanol unit for recovery. The wastewater in the condenser tank 20 is sent to the water stripping system of the butanol and octanol unit by wastewater pump 22 to recover the organic phase. The bottom material of distillation column 18 is a mixture of butanol (n-butanol and isobutanol) and water, which is sent to distillation column 32 by bottom pump 24 as its feed.

[0038] The operating pressure of the No. 2 distillation column 18 is -30KPa to -10KPa, the bottom temperature is 133℃ to 155℃, the top temperature is 93℃ to 111℃, and the reflux ratio is 1.5 to 5.5.

[0039] Step 4: The material entering distillation column 25 (No. 3) undergoes distillation separation. The top material consists of butyl butyrate, C5-C7 compounds, and a trace amount of water. After condensation in condenser 26 (No. 3), the material flows into condenser 27 (No. 3). The condensate in condenser 27 is split into two streams by reflux pump 28 (No. 3): one stream returns to distillation column 25 as reflux, and the other stream, containing butyl butyrate, C5-C7, and other intermediate components, is sent to the waste liquid tank of the butanol and octanol unit for periodic sale. The wastewater in the condenser 27 is pumped by wastewater pump 29 (No. 3) to the steam stripping system of the butanol and octanol unit to recover the organic phase. The bottom material of distillation column 25 consists of octanol, EPA, EHA, and a small amount of uncracked heavy components. It is pumped by bottom pump 31 (No. 3) to distillation column 38 (No. 5) as feed.

[0040] The operating pressure of the No. 3 distillation column 25 is -50KPa to -30KPa, the bottom temperature is 168℃ to 184℃, the top temperature is 150℃ to 170℃, and the reflux ratio is 3 to 7.

[0041] Step 5: The material entering distillation column 32 is separated by distillation. The top material is water and trace amounts of mixed butanol (n-butanol and isobutanol). After being condensed by condenser 33 of distillation column 4, it flows into condenser 34 of distillation column 4. The condensate in condenser 34 of distillation column 4 is split into two streams by reflux pump 35 of distillation column 4: one stream returns to distillation column 32 as reflux, and the other stream goes to the water stripping system of the butanol and octanol unit to recover the organic phase. The bottom material of distillation column 32 is mixed butanol. The mixed butanol is collected by bottom pump 37 of distillation column 4 and sent to the butanol distillation system of the butanol and octanol unit for recovery.

[0042] The operating pressure of the No. 4 distillation column 32 is -150KPa to -100KPa, the bottom temperature is 115℃ to 125℃, the top temperature is 94℃ to 108℃, and the reflux ratio is 4 to 8.

[0043] Step 6: The material entering the No. 5 distillation column 38 is separated by distillation. The top material is crude octanol (octanol, EPA, EHA), which is condensed by the No. 5 distillation column condenser 39 and flows into the No. 5 distillation column condenser tank 40. The condensate in the No. 5 distillation column condenser tank 40 is divided into two streams by the No. 5 distillation column reflux pump 41: one stream is returned to the No. 5 distillation column 38 as reflux, and the other stream is taken out as crude octanol and sent to the octanol distillation system of the butanol and octanol unit for recovery. The bottom material of the No. 5 distillation column 38 is uncracked heavy components and a small amount of crude octanol, which is sent to the cracking feed tank 10 for recycling by the No. 5 distillation column bottom pump 43.

[0044] The operating pressure of the No. 5 distillation column 38 is -70KPa to -30KPa, the bottom temperature is 178℃ to 196℃, the top temperature is 164℃ to 178℃, and the reflux ratio is 3.5 to 7.5.

[0045] This invention efficiently degrades C12 and C16 compounds in butanol and octanol residue into C4 and C8 components, and then refines and recovers mixed butyraldehyde (n-butyraldehyde and isobutyraldehyde), mixed butanol (n-butanol and isobutanol), and crude octanol (octanol, EPA, and EHA) from the residue. The recovery rate of the residue is over 90%, achieving the goal of fully utilizing waste and turning waste into treasure. The pyrolysis agent used in this invention to achieve the above objectives has the advantages of low price, small dosage, simple preparation, and low pyrolysis temperature.

[0046] Example 1 The method for cracking and refining the butanol / octanol residue in this embodiment includes the following steps: Step 1: The butanol and octanol residue in the cracking feed tank 10 is pumped to the cracking distillation vessel 3 at a flow rate of 2 t / h via the cracking feed pump 9. Simultaneously, the cracking agent in the cracking agent tank 1 is pumped to the cracking distillation vessel 3 via the cracking agent feed pump 2. The amount of cracking agent used is 0.1% of the residue mass. The cracking agent reacts with the C12 and C16 in the residue, cracking them into C4 and C8 components. These components, along with the original C4-C8 components in the residue, are distilled to the top of the cracking distillation vessel 3. After being condensed by the cracking distillation vessel condenser 4, they flow into the cracking distillation vessel condenser tank 5. The condensate in the cracking distillation vessel condenser tank 5 is divided into two streams by the cracking distillation vessel reflux pump 6: one stream returns to the cracking distillation vessel 3 as reflux, and the other stream goes to the No. 1 rectification column 11 as its feed. Every 8 hours, a portion of the liquid in the cracking distillation vessel 3 (6.5% of the liquid volume) is discharged to the waste tank of the butanol and octanol unit via the bottom pump 8 to prevent the cracking agent from accumulating in the cracking distillation vessel 3 and causing the liquid to coke.

[0047] The pyrolysis agent is an alkaline mixed liquid with the following mass composition: sodium hydroxide 34%, potassium hydroxide 26%, water 35%, ethylene glycol 2%, ethanol 0.8%, potassium permanganate 1.5%, barium hydroxide 0.2%, and sodium tetraborate 0.5%.

[0048] The operating pressure of the pyrolysis distillation vessel 3 is -80 kPa, the bottom temperature is 200°C, the top temperature is 140°C, and the reflux ratio is 0.1.

[0049] Step 2: The material entering distillation column 11 undergoes distillation separation. The top material, consisting of C4 and lower components (water, n-butyraldehyde, isobutyraldehyde, n-butanol, isobutanol, etc.), is condensed by condenser 12 and flows into condenser tank 13. The condensate is divided into two streams by reflux pump 14: one stream returns to distillation column 11 as reflux, and the other goes to distillation column 2 as feed. The bottom material of distillation column 11, consisting of components above C4 (C5~C7, butyl butyrate, EPA, EHA, octanol, and a small amount of uncracked heavy components, etc.), is sent to distillation column 3 as feed by bottom pump 17. The wastewater in the condenser tank 13 is sent to the steam stripping system of the butanol / octanol unit by wastewater pump 15 to recover the organic phase.

[0050] The operating pressure of distillation column 11 is -100 kPa, the bottom temperature is 155°C, the top temperature is 122°C, and the reflux ratio is 3.

[0051] Step 3: The material entering distillation column 18 is separated by distillation. The top material is a mixture of butyraldehyde (n-butyraldehyde and isobutyraldehyde) and a trace amount of water. After being condensed by condenser 19 of distillation column 18, it flows into condenser tank 20 of distillation column 18. The condensate is divided into two streams by reflux pump 21 of distillation column 18: one stream returns to distillation column 18 as reflux, and the other stream, containing the mixed butyraldehyde, is sent to the butyraldehyde distillation system of the butanol and octanol unit for recovery. The bottom material of distillation column 18 is a mixture of butanol (n-butanol and isobutanol) and water, which is sent to distillation column 32 of distillation column 4 as its feed by bottom pump 24 of distillation column 18. The wastewater in the condenser tank 20 of distillation column 18 is sent to the water stripping system of the butanol and octanol unit of distillation column 18 by wastewater pump 22 of distillation column 18 to recover the organic phase.

[0052] Among them, the operating pressure of distillation column 2 is -30 kPa, the bottom temperature is 133°C, the top temperature is 93°C, and the reflux ratio is 5.5.

[0053] Step 4: The material entering distillation column 25 (No. 3) undergoes distillation separation. The top material consists of butyl butyrate, C5-C7 compounds, and trace amounts of water. After condensation in condenser 26 (No. 3), the condensate flows into condenser tank 27 (No. 3). The condensate is split into two streams by reflux pump 28 (No. 3): one stream returns to distillation column 25 as reflux, while the other stream, containing butyl butyrate, C5-C7, and other intermediate components, is sent to the waste liquid tank of the butanol and octanol unit for periodic sale. The bottom material of distillation column 25 consists of octanol, EPA, EHA, and a small amount of uncracked heavy components. This material is sent to distillation column 38 (No. 5) as feed via bottom pump 31 (No. 3). The wastewater in the condenser tank 27 (No. 3) is sent to the water stripping system of the butanol and octanol unit via wastewater pump 29 (No. 3) to recover the organic phase.

[0054] Among them, the operating pressure of distillation column 25 is -50KPa, the bottom temperature is 168℃, the top temperature is 150℃, and the reflux ratio is 3.

[0055] Step 5: The material entering distillation column 32 is separated by distillation. The top material is water and trace amounts of mixed butanol (n-butanol and isobutanol). After being condensed by condenser 33 of distillation column 4, it flows into condenser tank 34 of distillation column 4. The condensate is divided into two streams by reflux pump 35 of distillation column 4: one stream returns to distillation column 32 as reflux, and the other stream goes to the water stripping system of the butanol and octanol unit to recover the organic phase. The bottom material of distillation column 32 is mixed butanol. The mixed butanol is collected by bottom pump 37 of distillation column 4 and sent to the butanol distillation system of the butanol and octanol unit for recovery.

[0056] Among them, the operating pressure of distillation column 32 of No. 4 is -150KPa, the bottom temperature is 115℃, the top temperature is 94℃, and the reflux ratio is 6.

[0057] Step 6: The material entering the No. 5 distillation column 38 is separated by distillation. The top material is crude octanol (octanol, EPA, EHA), which is condensed by the No. 5 distillation column condenser 39 and flows into the No. 5 distillation column condenser tank 40. The condensate is divided into two streams by the No. 5 distillation column reflux pump 41: one stream returns to the No. 5 distillation column 38 as reflux, and the other stream is taken out as crude octanol and sent to the octanol distillation system of the butanol unit for recovery. The bottom material of the No. 5 distillation column 38 is uncracked heavy components and a small amount of crude octanol, which is sent to the cracking feed tank 10 for recycling by the No. 5 distillation column bottom pump 43.

[0058] Among them, the operating pressure of the No. 5 distillation column 38 is -70 kPa, the bottom temperature is 178°C, the top temperature is 164°C, and the reflux ratio is 5.5.

[0059] In this embodiment, the recovery rate of butanol residue was 91.8%.

[0060] Example 2 The method for cracking and refining the butanol / octanol residue in this embodiment includes the following steps: Step 1: The butanol and octanol residue in the cracking feed tank 10 is pumped to the cracking distillation vessel 3 at a flow rate of 3 t / h via the cracking feed pump 9. Simultaneously, the cracking agent in the cracking agent tank 1 is pumped to the cracking distillation vessel 3 via the cracking agent feed pump 2. The amount of cracking agent used is 0.3% of the residue mass. The cracking agent reacts with the C12 and C16 in the residue, cracking them into C4 and C8 components. These components, along with the original C4-C8 components in the residue, are distilled to the top of the cracking distillation vessel 3, condensed by the cracking distillation vessel condenser 4, and then flow into the cracking distillation vessel condenser tank 5. The condensate in the cracking distillation vessel condenser tank 5 is divided into two streams by the cracking distillation vessel reflux pump 6: one stream returns to the cracking distillation vessel 3 as reflux, and the other stream goes to the No. 1 rectification column 11 as its feed. Every 6 hours, a portion of the liquid in the cracking distillation vessel 3 (5% of the liquid volume) is discharged to the waste liquid tank of the butanol and octanol unit via the bottom pump 8 to prevent the cracking agent from accumulating in the cracking distillation vessel 3 and causing the liquid to coke.

[0061] The pyrolysis agent is an alkaline mixed liquid with the following composition by mass: sodium hydroxide 18%, potassium hydroxide 12%, water 55%, ethylene glycol 6%, ethanol 1.2%, potassium permanganate 2%, barium hydroxide 0.3%, and sodium tetraborate 1.5%.

[0062] The operating pressure of the pyrolysis distillation vessel 3 is -50 kPa, the bottom temperature is 240°C, the top temperature is 170°C, and the reflux ratio is 0.09.

[0063] Step 2: The material entering distillation column 11 undergoes distillation separation. The top material, consisting of C4 and lower components (water, n-butyraldehyde, isobutyraldehyde, n-butanol, isobutanol, etc.), is condensed by condenser 12 and flows into condenser tank 13. The condensate is divided into two streams by reflux pump 14: one stream returns to distillation column 11 as reflux, and the other goes to distillation column 2 as feed. The bottom material of distillation column 11, consisting of components above C4 (C5~C7, butyl butyrate, EPA, EHA, octanol, and a small amount of uncracked heavy components, etc.), is sent to distillation column 3 as feed by bottom pump 17. The wastewater in the condenser tank 13 is sent to the steam stripping system of the butanol / octanol unit by wastewater pump 15 to recover the organic phase.

[0064] The operating pressure of distillation column 11 is -60 kPa, the bottom temperature is 175°C, the top temperature is 144°C, and the reflux ratio is 2.

[0065] Step 3: The material entering distillation column 18 is separated by distillation. The top material is a mixture of butyraldehyde (n-butyraldehyde and isobutyraldehyde) and a trace amount of water. After being condensed by condenser 19 of distillation column 18, it flows into condenser tank 20 of distillation column 18. The condensate is divided into two streams by reflux pump 21 of distillation column 18: one stream returns to distillation column 18 as reflux, and the other stream, containing the mixed butyraldehyde, is sent to the butyraldehyde distillation system of the butanol and octanol unit for recovery. The bottom material of distillation column 18 is a mixture of butanol (n-butanol and isobutanol) and water, which is sent to distillation column 32 of distillation column 4 as its feed by bottom pump 24 of distillation column 18. The wastewater in the condenser tank 20 of distillation column 18 is sent to the water stripping system of the butanol and octanol unit of distillation column 18 by wastewater pump 22 of distillation column 18 to recover the organic phase.

[0066] The operating pressure of distillation column 2 is -10 kPa, the bottom temperature is 155°C, the top temperature is 111°C, and the reflux ratio is 3.5.

[0067] Step 4: The material entering distillation column 25 (No. 3) undergoes distillation separation. The top material consists of butyl butyrate, C5-C7 compounds, and trace amounts of water. After condensation in condenser 26 (No. 3), the condensate flows into condenser tank 27 (No. 3). The condensate is split into two streams by reflux pump 28 (No. 3): one stream returns to distillation column 25 as reflux, while the other stream, containing butyl butyrate, C5-C7, and other intermediate components, is sent to the waste liquid tank of the butanol and octanol unit for periodic sale. The bottom material of distillation column 25 consists of octanol, EPA, EHA, and a small amount of uncracked heavy components. This material is sent to distillation column 38 (No. 5) as feed via bottom pump 31 (No. 3). The wastewater in the condenser tank 27 (No. 3) is sent to the water stripping system of the butanol and octanol unit via wastewater pump 29 (No. 3) to recover the organic phase.

[0068] The operating pressure of distillation column 25 is -30 kPa, the bottom temperature is 184°C, the top temperature is 170°C, and the reflux ratio is 7.

[0069] Step 5: The material entering distillation column 32 is separated by distillation. The top material is water and trace amounts of mixed butanol (n-butanol and isobutanol). After being condensed by condenser 33 of distillation column 4, it flows into condenser tank 34 of distillation column 4. The condensate is divided into two streams by reflux pump 35 of distillation column 4: one stream returns to distillation column 32 as reflux, and the other stream goes to the water stripping system of the butanol and octanol unit to recover the organic phase. The bottom material of distillation column 32 is mixed butanol. The mixed butanol is collected by bottom pump 37 of distillation column 4 and sent to the butanol distillation system of the butanol and octanol unit for recovery.

[0070] Among them, the operating pressure of distillation column 32 of No. 4 is -100KPa, the bottom temperature is 125℃, the top temperature is 108℃, and the reflux ratio is 4.

[0071] Step 6: The material entering the No. 5 distillation column 38 is separated by distillation. The top material is crude octanol (octanol, EPA, EHA), which is condensed by the No. 5 distillation column condenser 39 and flows into the No. 5 distillation column condenser tank 40. The condensate is divided into two streams by the No. 5 distillation column reflux pump 41: one stream returns to the No. 5 distillation column 38 as reflux, and the other stream is taken out as crude octanol and sent to the octanol distillation system of the butanol unit for recovery. The bottom material of the No. 5 distillation column 38 is uncracked heavy components and a small amount of crude octanol, which is sent to the cracking feed tank 10 for recycling by the No. 5 distillation column bottom pump 43.

[0072] Among them, the operating pressure of the No. 5 distillation column 38 is -30 kPa, the bottom temperature is 196℃, the top temperature is 178℃, and the reflux ratio is 3.5.

[0073] In this embodiment, the recovery rate of butanol residue was 90.9%.

[0074] Example 3 The method for cracking and refining the butanol / octanol residue in this embodiment includes the following steps: Step 1: The butanol and octanol residue in the cracking feed tank 10 is pumped to the cracking distillation vessel 3 at a flow rate of 4 t / h via the cracking feed feed pump 9. Simultaneously, the cracking agent in the cracking agent tank 1 is pumped to the cracking distillation vessel 3 via the cracking agent feed pump 2. The amount of cracking agent used is 0.5% of the residue mass. The cracking agent reacts with the C12 and C16 in the residue, cracking them into C4 and C8 components. These components, along with the original C4-C8 components in the residue, are distilled to the top of the cracking distillation vessel 3, condensed by the cracking distillation vessel condenser 4, and then flow into the cracking distillation vessel condenser tank 5. The condensate in the cracking distillation vessel condenser tank 5 is divided into two streams by the cracking distillation vessel reflux pump 6: one stream returns to the cracking distillation vessel 3 as reflux, and the other stream goes to the No. 1 rectification column 11 as its feed. Every 10 hours, a portion of the liquid in the cracking distillation vessel 3 (8% of the liquid volume) is discharged to the waste liquid tank of the butanol and octanol unit via the bottom pump 8 to prevent the cracking agent from accumulating in the cracking distillation vessel 3 and causing the liquid to coke.

[0075] The pyrolysis agent is an alkaline mixed liquid with the following composition by mass: sodium hydroxide 26%, potassium hydroxide 19%, water 45%, ethylene glycol 4%, ethanol 0.4%, potassium permanganate 1%, barium hydroxide 0.1%, and sodium tetraborate 1%.

[0076] The operating pressure of the pyrolysis distillation vessel 3 is -65 kPa, the bottom temperature is 220°C, the top temperature is 155°C, and the reflux ratio is 0.08.

[0077] Step 2: The material entering distillation column 11 undergoes distillation separation. The top material, consisting of C4 and lower components (water, n-butyraldehyde, isobutyraldehyde, n-butanol, isobutanol, etc.), is condensed by condenser 12 and flows into condenser tank 13. The condensate is divided into two streams by reflux pump 14: one stream returns to distillation column 11 as reflux, and the other goes to distillation column 2 as feed. The bottom material of distillation column 11, consisting of components above C4 (C5~C7, butyl butyrate, EPA, EHA, octanol, and a small amount of uncracked heavy components, etc.), is sent to distillation column 3 as feed by bottom pump 17. The wastewater in the condenser tank 13 is sent to the steam stripping system of the butanol / octanol unit by wastewater pump 15 to recover the organic phase.

[0078] The operating pressure of distillation column 11 is -80 kPa, the bottom temperature is 165°C, the top temperature is 133°C, and the reflux ratio is 4.

[0079] Step 3: The material entering distillation column 18 is separated by distillation. The top material is a mixture of butyraldehyde (n-butyraldehyde and isobutyraldehyde) and a trace amount of water. After being condensed by condenser 19 of distillation column 18, it flows into condenser tank 20 of distillation column 18. The condensate is divided into two streams by reflux pump 21 of distillation column 18: one stream returns to distillation column 18 as reflux, and the other stream, containing the mixed butyraldehyde, is sent to the butyraldehyde distillation system of the butanol and octanol unit for recovery. The bottom material of distillation column 18 is a mixture of butanol (n-butanol and isobutanol) and water, which is sent to distillation column 32 of distillation column 4 as its feed by bottom pump 24 of distillation column 18. The wastewater in the condenser tank 20 of distillation column 18 is sent to the water stripping system of the butanol and octanol unit of distillation column 18 by wastewater pump 22 of distillation column 18 to recover the organic phase.

[0080] The operating pressure of distillation column 2 is -20 kPa, the bottom temperature is 144°C, the top temperature is 102°C, and the reflux ratio is 1.5.

[0081] Step 4: The material entering distillation column 25 (No. 3) undergoes distillation separation. The top material consists of butyl butyrate, C5-C7 compounds, and trace amounts of water. After condensation in condenser 26 (No. 3), the condensate flows into condenser tank 27 (No. 3). The condensate is split into two streams by reflux pump 28 (No. 3): one stream returns to distillation column 25 as reflux, while the other stream, containing butyl butyrate, C5-C7, and other intermediate components, is sent to the waste liquid tank of the butanol and octanol unit for periodic sale. The bottom material of distillation column 25 consists of octanol, EPA, EHA, and a small amount of uncracked heavy components. This material is sent to distillation column 38 (No. 5) as feed via bottom pump 31 (No. 3). The wastewater in the condenser tank 27 (No. 3) is sent to the water stripping system of the butanol and octanol unit via wastewater pump 29 (No. 3) to recover the organic phase.

[0082] The operating pressure of distillation column 25 is -40 kPa, the bottom temperature is 176°C, the top temperature is 160°C, and the reflux ratio is 5.

[0083] Step 5: The material entering distillation column 32 is separated by distillation. The top material is water and trace amounts of mixed butanol (n-butanol and isobutanol). After being condensed by condenser 33 of distillation column 4, it flows into condenser tank 34 of distillation column 4. The condensate is divided into two streams by reflux pump 35 of distillation column 4: one stream returns to distillation column 32 as reflux, and the other stream goes to the water stripping system of the butanol and octanol unit to recover the organic phase. The bottom material of distillation column 32 is mixed butanol. The mixed butanol is collected by bottom pump 37 of distillation column 4 and sent to the butanol distillation system of the butanol and octanol unit for recovery.

[0084] Among them, the operating pressure of distillation column 32 of No. 4 is -125KPa, the bottom temperature is 120℃, the top temperature is 101℃, and the reflux ratio is 8.

[0085] Step 6: The material entering the No. 5 distillation column 38 is separated by distillation. The top material is crude octanol (octanol, EPA, EHA), which is condensed by the No. 5 distillation column condenser 39 and flows into the No. 5 distillation column condenser tank 40. The condensate is divided into two streams by the No. 5 distillation column reflux pump 41: one stream returns to the No. 5 distillation column 38 as reflux, and the other stream is taken out as crude octanol and sent to the octanol distillation system of the butanol unit for recovery. The bottom material of the No. 5 distillation column 38 is uncracked heavy components and a small amount of crude octanol, which is sent to the cracking feed tank 10 for recycling by the No. 5 distillation column bottom pump 43.

[0086] Among them, the operating pressure of the No. 5 distillation column 38 is -50 kPa, the bottom temperature is 187°C, the top temperature is 171°C, and the reflux ratio is 7.5.

[0087] In this embodiment, the recovery rate of butanol residue was 91.2%.

[0088] Although the functions and working processes of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific functions and working processes described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these are within the protection scope of the present invention.

Claims

1. A method for cracking and refining butanol / octanol residue, characterized in that, Includes the following steps: Step 1: The butanol and octanol residue in the cracking feed tank (10) is transported to the cracking distillation kettle (3), and the cracking agent in the cracking agent tank (1) is transported to the cracking distillation kettle (3). The cracking agent reacts with C12 and C16 in the butanol and octanol residue to crack them into C4 and C8 components. These components, along with the original C4~C8 components in the butanol and octanol residue, are distilled to the top of the cracking distillation kettle (3). After being condensed by the cracking distillation kettle condenser (4), they flow into the cracking distillation kettle condenser tank (5). The condensate is output in two streams: one stream returns to the cracking distillation kettle (3) as reflux, and the other stream goes to the No. 1 distillation column (11) as its feed. The liquid in the cracking distillation kettle (3) is periodically discharged to the butanol and octanol unit waste tank through the cracking distillation kettle bottom pump (8). Step 2: The material entering the No. 1 distillation column (11) is separated by distillation. The material at the top of the column is a component of C4 and below. After being condensed by the No. 1 distillation column condenser (12), it flows into the No. 1 distillation column condenser tank (13). The condensate is output in two streams: one stream returns to the No. 1 distillation column (11) as reflux, and the other stream goes to the No. 2 distillation column (18) as its feed. The wastewater in the condenser tank (13) of the No. 1 distillation column is sent to the water stripping system of the butanol and octanol unit to recover the organic phase. The bottom material of the No. 1 distillation column (11) is a component with C4 or higher, which is transported to the No. 3 distillation column (25) as its feed; Step 3: The material entering the No. 2 distillation column (18) is separated by distillation. The material at the top of the column is a mixture of butyraldehyde and a trace amount of water. After being condensed by the No. 2 distillation column condenser (19), it flows into the No. 2 distillation column condenser (20). The condensate is output in two streams: one stream returns to the No. 2 distillation column (18) as reflux, and the other stream is taken out as a mixture of butyraldehyde and sent to the butyraldehyde distillation system of the butanol and octanol unit for recovery. The wastewater in the condenser (20) of the No. 2 distillation column is sent to the water stripping system of the butanol and octanol unit to recover the organic phase. The material at the bottom of the No. 2 distillation column (18) is a mixture of butanol and water, which is sent to the No. 4 distillation column (32) as its feed. Step 4: The material entering the No. 3 distillation column (25) is separated by distillation. The top material is butyl butyrate, C5-C7 and a trace amount of water. After being condensed by the No. 3 distillation column condenser (26), it flows into the No. 3 distillation column condenser tank (27). The condensate is output in two streams: one stream is returned to the No. 3 distillation column (25) as reflux, and the other stream is used to collect intermediate components and send them to the waste liquid tank of the butanol and octanol unit for periodic external sale. The wastewater in the boot of the No. 3 distillation column condenser tank (27) is sent to the water stripping system of the butanol and octanol unit through the No. 3 distillation column wastewater pump (29) to recover the organic phase. The bottom material of the No. 3 distillation column (25) is octanol, EPA, EHA and a small amount of uncracked heavy components, which are sent to the No. 5 distillation column (38) as its feed. Step 5: The material entering the No. 4 distillation column (32) is separated by distillation. The material at the top of the column is water and a trace amount of mixed butanol. After being condensed by the No. 4 distillation column condenser (33), it flows into the No. 4 distillation column condenser tank (34). The condensate is output in two streams: one stream returns to the No. 4 distillation column (32) as reflux, and the other stream goes to the water stripping system of the butanol and octanol unit to recover the organic phase. The material at the bottom of the No. 4 distillation column (32) is mixed butanol. The mixed butanol is collected by the bottom pump (37) of the No. 4 distillation column and sent to the butanol distillation system of the butanol and octanol unit for recovery. Step 6: The material entering the No. 5 distillation column (38) is separated by distillation. The material at the top of the column is crude octanol. After being condensed by the No. 5 distillation column condenser (39), it flows into the No. 5 distillation column condenser tank (40). The condensate inside is output in two streams: one stream returns to the No. 5 distillation column (38) as reflux, and the other stream is taken out as crude octanol and sent to the octanol distillation system of the butanol and octanol unit for recovery. The material at the bottom of the No. 5 distillation column (38) is uncracked heavy components and a small amount of crude octanol, which is sent to the cracking feed tank (10) for recycling.

2. The method for cracking and refining the butanol / octanol residue according to claim 1, characterized in that, In the first step, the flow rate of the butanol and octanol residue in the cracking feed tank (10) into the cracking distillation kettle (3) is 2~4 t / h. The cracking agent is an alkaline mixed liquid with the following mass composition: sodium hydroxide 18%~34%, potassium hydroxide 12%~26%, water 35%~55%, ethylene glycol 2%~6%, ethanol 0.4%~1.2%, potassium permanganate 1%~2%, barium hydroxide 0.1%~0.3%, sodium tetraborate 0.5%~1.5%. The amount of cracking agent used is 0.1%~0.5% of the mass of the butanol and octanol residue. The bottom pump (8) of the cracking distillation kettle discharges part of the kettle liquid every 6~10 hours, and the discharge amount is 5%~8% of the kettle liquid mass. The operating pressure of the cracking distillation kettle (3) is -80KPa~-50KPa, the bottom temperature is 200℃~240℃, the top temperature is 140℃~170℃, and the reflux ratio is 0.08~0.

1.

3. The method for cracking and refining butanol / octanol residue according to claim 1, characterized in that, The operating pressure of the No. 1 distillation column (11) in the second step is -100KPa~-60KPa, the bottom temperature is 155℃~175℃, the top temperature is 122℃~144℃, and the reflux ratio is 2~4.

4. The method for cracking and refining butanol / octanol residue according to claim 1, characterized in that, The operating pressure of the No. 2 distillation column (18) mentioned in the third step is -30KPa~-10KPa, the bottom temperature is 133℃~155℃, the top temperature is 93℃~111℃, and the reflux ratio is 1.5~5.

5.

5. The method for cracking and refining the butanol / octanol residue according to claim 1, characterized in that, The operating pressure of the No. 3 distillation column (25) mentioned in the fourth step is -50KPa~-30KPa, the bottom temperature is 168℃~184℃, the top temperature is 150℃~170℃, and the reflux ratio is 3~7.

6. The method for cracking and refining the butanol / octanol residue according to claim 1, characterized in that, The operating pressure of the No. 4 distillation column (32) mentioned in step 5 is -150KPa~-100KPa, the bottom temperature is 115℃~125℃, the top temperature is 94℃~108℃, and the reflux ratio is 4~8.

7. The method for cracking and refining butanol / octanol residue according to claim 1, characterized in that, The operating pressure of the No. 5 distillation column (38) mentioned in step 6 is -70KPa~-30KPa, the bottom temperature is 178℃~196℃, the top temperature is 164℃~178℃, and the reflux ratio is 3.5~7.5.

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