Separation and extraction process for isopropyl ether in bisphenol A wastewater
By employing a preheating-distillation-extractive distillation process in bisphenol A wastewater, and optimizing the number of trays and reflux ratio, the problem of incomplete separation of isopropyl ether and phenol in bisphenol A wastewater was solved, achieving efficient recovery of isopropyl ether and reducing environmental pollution.
Patent Information
- Application Number
- CN202511472140.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-15
- Publication Date
- 2025-11-21
AI Technical Summary
Existing technologies have poor separation effects between isopropyl ether and phenol in bisphenol A wastewater, leading to waste of isopropyl ether and environmental pollution, and are also detrimental to the subsequent purification of BPA.
Bisphenol A wastewater is preheated by a preheater and then enters a distillation column for distillation. A mixture of isopropyl ether is collected from the top gas outlet of the column. Acetone is then separated and dehydrated in an extractive distillation column. Ethylene glycol is used as the extractant. The theoretical plate number, feed position and reflux ratio are optimized to improve the separation effect.
This method achieves a phenol content of less than 0.05% in isopropyl ether, meeting the raw material requirements of subsequent processes and realizing efficient recovery of isopropyl ether and environmental protection.
Smart Images
Figure CN120987736A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of chemical wastewater treatment, and in particular to a process for separating and extracting isopropyl ether from bisphenol A wastewater. Background Technology
[0002] Bisphenol A (BPA), also known as 2,2-bis(p-hydroxyphenyl)propane, is used in the production of various polymer materials such as polycarbonate, epoxy resin, polyester resin, and polyphenylene ether resin. It is also used in the production of fine chemical products such as plasticizers, flame retardants, plastic antioxidants, heat stabilizers, rubber antioxidants, ultraviolet absorbers, bactericides, and coatings.
[0003] BPA is produced by the condensation of phenol and acetone in an acidic medium. The production process generates a series of saline wastewater containing isopropyl ether, phenol, and acetone. Isopropyl ether is an important raw material and solvent, widely used in chemical, environmental protection, and pharmaceutical industries. Direct discharge of it will pollute the environment and is also detrimental to the subsequent refining of BPA.
[0004] Furthermore, phenol is a common chemical raw material that can participate in various chemical reactions. To avoid the impact of residual phenol on the subsequent application of isopropyl ether, the separation of the two should be ensured. Case studies of separating isopropyl ether and phenol from bisphenol A wastewater are rare.
[0005] Therefore, in order to avoid isopropyl ether waste, save costs, improve BPA purity, and protect the environment, it is necessary to establish an efficient isopropyl ether recovery process from BPA wastewater. Summary of the Invention
[0006] The purpose of this invention is to address the technical difficulty in separating and extracting isopropyl ether from bisphenol A (BPA) wastewater, and to provide a process for separating and extracting isopropyl ether from BPA wastewater. The BPA wastewater is preheated in a preheater and then fed into a distillation column for distillation. The isopropyl ether mixture is collected from the overhead gas outlet of the distillation column and then further separated into acetone in an extractive distillation column, followed by dehydration and drying to obtain isopropyl ether. The isopropyl ether obtained using this method has a phenol content of less than 0.05%, meeting the raw material requirements for subsequent processes.
[0007] The technical solution adopted to achieve the purpose of this invention is: A process for separating and extracting isopropyl ether from bisphenol A wastewater includes the following steps: Step 1: Preheat the bisphenol A wastewater using a preheater; Step 2: The preheated bisphenol A wastewater is transported to the distillation column through the inlet of the distillation column for distillation; Step 3: The isopropyl ether mixture is collected from the top gas outlet of the distillation column; Step 4: The obtained isopropyl ether mixture is separated from acetone by an extractive distillation column and then dehydrated and dried to obtain isopropyl ether.
[0008] Furthermore, the process system includes a preheater, a distillation column, an extractive distillation column, and a storage tank; The preheater is connected to the material inlet of the distillation column; The overhead gas outlet of the distillation column is connected to the feed inlet of the extractive distillation column; the extractant outlet of the extractive distillation column is connected to the extractant feed inlet of the extractive distillation column. The side outlet of the extractive distillation column is connected to the storage tank.
[0009] Furthermore, the theoretical plate number of the distillation column is 27-30. This invention investigated the effect of the theoretical plate number on the phenol content in the top isopropyl ether of the isopropyl ether column. When the theoretical plate number is 18-23, the phenol content at the top of the column decreases rapidly with increasing theoretical plate number. When the theoretical plate number is 27, the required phenol content at the top of the column is met.
[0010] Furthermore, the material inlet is located at trays 14-16 from bottom to top. This invention investigated the effect of the feed location on the phenol content in the top of the isopropyl ether column. As the number of trays at the feed location increases, the phenol content at the top of the column gradually decreases and then tends to stabilize. When the feed location is at trays 6-11, the phenol content at the top of the column decreases rapidly with the increase of the number of trays; when the feed location is 14, the phenol content at the top of the column meets the requirements. Further increasing the number of trays at the feed location does not significantly change the phenol content at the top of the column.
[0011] Furthermore, the reflux ratio of the distillation column is 0.9-1.0. This invention investigated the effect of the reflux ratio on the phenol content in the top isopropyl ether of the isopropyl ether column. When the reflux ratio is 0.2-0.6, the top phenol content decreases rapidly with increasing reflux ratio. From a reflux ratio of 0.6 to 0.9, the top phenol content decreases slightly. When the reflux ratio is 0.9, the top phenol content meets the requirements.
[0012] Furthermore, the extractant in the extractive distillation column is ethylene glycol.
[0013] Furthermore, the theoretical number of trays in the extractive distillation column is 20-40, and the feed inlet is located at tray 10-20.
[0014] Furthermore, the extractant inlet is located at the 3rd to 10th tray from the bottom.
[0015] Furthermore, the reflux ratio of the extractive distillation column is 0.8-2.
[0016] Furthermore, the phenol content in the obtained isopropyl ether is less than 0.05%. The isopropyl ether at the top of the separated column contains virtually no phenol, meeting the needs of subsequent production.
[0017] Compared with the prior art, the beneficial effects of the present invention are: The present invention provides a process for the separation and extraction of isopropyl ether from bisphenol A wastewater. The bisphenol A wastewater is preheated in a preheater and then fed into a distillation column for distillation. An isopropyl ether mixture is collected from the top gas outlet of the distillation column and then separated from acetone in an extractive distillation column. The acetone is then dehydrated and dried to obtain isopropyl ether. The isopropyl ether obtained by this method has a phenol content of less than 0.05%, meeting the raw material requirements for subsequent processes. Attached Figure Description
[0018] Figure 1 The diagram shows a schematic of the isopropyl ether separation and extraction process system in bisphenol A wastewater. In the diagram: 1-Preheater, 2-Distillation column, 2-1-Material inlet, 2-2-Top gas outlet, 2-3-Bottom liquid outlet, 3-Extractive distillation column 3, 3-1-Feed inlet, 3-2-Extractant outlet, 3-3-Extractant inlet, Storage tank 4. Detailed Implementation
[0019] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
[0020] Example 1 A process system for separating and extracting isopropyl ether from bisphenol A wastewater, such as Figure 1 As shown, it includes a preheater 1, a distillation column 2, an extractive distillation column 3, and a storage tank 4; The preheater 1 is connected to the material inlet 2-1 of the distillation column 2 so that the preheated bisphenol A wastewater enters the distillation column 2 through the material inlet 2-1 for distillation. The top gas outlet 2-2 of the distillation column 2 is connected to the feed inlet 3-1 of the extractive distillation column 3, so that the mixture containing isopropyl ether, acetone and water after distillation is fed into the extractive distillation column 3 through the feed inlet 3-1 for further separation; the phenol and heavy components remaining after distillation are discharged through the bottom liquid outlet 2-3.
[0021] The extractant outlet 3-2 of the extractive distillation column 3 is connected to the extractant inlet 3-3 of the extractive distillation column 3 so that the extractant can be recycled. The side outlet 3-4 of the extractive distillation column 3 is connected to the storage tank 4. Isopropyl ether, after being further separated and deacetone removed, flows into the storage tank 4 and is dried to obtain isopropyl ether.
[0022] Example 2
[0023] This embodiment and the comparative example are based on the process system in Example 1, and further investigate the theoretical number of trays in the distillation column.
[0024] A process system for separating and extracting isopropyl ether from bisphenol A wastewater includes the following steps: Step 1: Preheat the bisphenol A wastewater through a preheater; the bisphenol A wastewater comes from a chemical plant in Cangzhou and has the following composition: phenol 1822 kg / h, acetone 30 kg / h, isopropyl ether 3891 kg / h, water 138 kg / h, and heavy component impurities 191 kg / h.
[0025] Step 2: The preheated bisphenol A wastewater is transported to the distillation column for distillation; the material inlet is located at the 14th tray from the bottom; the feed rate is 6072.00 kg / h.
[0026] Step 3: The isopropyl ether mixture is collected from the overhead gas outlet of the distillation column; the theoretical plate number of the distillation column is 27; the reflux ratio of the distillation column is 0.9. The isopropyl ether mixture contains 95.83% isopropyl ether, 0.74% acetone, 3.40% water, and 0.03% phenol. The material discharged from the bottom liquid outlet contains 90.45% phenol, 9.48% heavy components, and 0.05% isopropyl ether, achieving efficient recovery of isopropyl ether.
[0027] Step 4: The obtained isopropyl ether mixture is separated from acetone by an extractive distillation column, and then dehydrated and dried to obtain isopropyl ether. The extractant in the extractive distillation column is ethylene glycol. The extractive distillation column has 20 theoretical plates, and the feed inlet is located at plate 10. The extractant feed inlet is also located at plate 10. The reflux ratio of the extractive distillation column is 2.
[0028] Comparative Example A process system for separating and extracting isopropyl ether from bisphenol A wastewater includes the following steps: Step 1: Preheat the bisphenol A wastewater through a preheater; the bisphenol A wastewater comes from a chemical plant in Cangzhou and has the following composition: phenol 1822 kg / h, acetone 30 kg / h, isopropyl ether 3891 kg / h, water 138 kg / h, and heavy component impurities 191 kg / h.
[0029] Step 2: The preheated bisphenol A wastewater is transported to the distillation column for distillation; the material inlet is located at the 14th tray from the bottom; the feed rate is 6072.00 kg / h.
[0030] Step 3: The isopropyl ether mixture is collected from the overhead gas outlet of the distillation column; the theoretical plate number of the distillation column is 25; the reflux ratio of the distillation column is 0.9. The isopropyl ether mixture contains 95.66% isopropyl ether, 0.74% acetone, 3.40% water, and 0.20% phenol. The phenol content is too high and does not meet the requirements for subsequent production.
[0031] Example 3
[0032] This embodiment and the comparative example are based on the process system in Example 1, and further investigate the influence of the material inlet on the separation effect.
[0033] A process system for separating and extracting isopropyl ether from bisphenol A wastewater includes the following steps: Step 1: Preheat the bisphenol A wastewater through a preheater; the bisphenol A wastewater comes from a chemical plant in Cangzhou and has the following composition: phenol 1822 kg / h, acetone 30 kg / h, isopropyl ether 3891 kg / h, water 138 kg / h, and heavy component impurities 191 kg / h.
[0034] Step 2: The preheated bisphenol A wastewater is transported to the distillation column for distillation; the material inlet is located at the 14th tray from the bottom.
[0035] Step 3: The isopropyl ether mixture is collected from the overhead gas outlet of the distillation column; the theoretical plate number of the distillation column is 30; the reflux ratio of the distillation column is 1.0. The isopropyl ether mixture contains 95.63% isopropyl ether, 0.82% acetone, 3.54% water, and 0.01% phenol. The material discharged from the bottom liquid outlet contains 90.48% phenol, 9.46% heavy components, and 0.04% isopropyl ether, achieving efficient recovery of isopropyl ether.
[0036] Step 4: The obtained isopropyl ether mixture is separated from acetone by an extractive distillation column, and then dehydrated and dried to obtain isopropyl ether. The extractant in the extractive distillation column is ethylene glycol. The theoretical number of plates in the extractive distillation column is 40, and the feed inlet is located at plate 20. The extractant feed inlet is located at plate 3. The reflux ratio of the extractive distillation column is 0.8.
[0037] Comparative Example A process system for separating and extracting isopropyl ether from bisphenol A wastewater includes the following steps: Step 1: Preheat the bisphenol A wastewater through a preheater; the bisphenol A wastewater comes from a chemical plant in Cangzhou and has the following composition: phenol 1822 kg / h, acetone 30 kg / h, isopropyl ether 3891 kg / h, water 138 kg / h, and heavy component impurities 191 kg / h.
[0038] Step 2: The preheated bisphenol A wastewater is transported to the distillation column for distillation; the material inlet is located at the 11th tray from the bottom.
[0039] Step 3: The isopropyl ether mixture is collected from the overhead gas outlet of the distillation column; the theoretical plate number of the distillation column is 30; the reflux ratio of the distillation column is 1.0. The isopropyl ether mixture contains 95.53% isopropyl ether, 0.80% acetone, 3.49% water, and 0.18% phenol. The phenol content is too high and does not meet the requirements for subsequent production.
[0040] Example 4
[0041] This embodiment and the comparative example are based on the process system in Example 1, and further study the effect of the distillation column reflux ratio on the separation effect.
[0042] A process system for separating and extracting isopropyl ether from bisphenol A wastewater includes the following steps: Step 1: Preheat the bisphenol A wastewater through a preheater; the bisphenol A wastewater comes from a chemical plant in Cangzhou and has the following composition: phenol 1822 kg / h, acetone 30 kg / h, isopropyl ether 3891 kg / h, water 138 kg / h, and heavy component impurities 191 kg / h.
[0043] Step 2: The preheated bisphenol A wastewater is transported to the distillation column for distillation; the material inlet is located at the 15th tray from the bottom.
[0044] Step 3: The isopropyl ether mixture is collected from the overhead gas outlet of the distillation column; the theoretical plate number of the distillation column is 28; the reflux ratio of the distillation column is 0.9. The isopropyl ether mixture contains 95.28% isopropyl ether, 1.05% acetone, 3.64% water, and 0.03% phenol. The material discharged from the bottom liquid outlet contains 90.42% phenol, 9.50% heavy components, and 0.06% isopropyl ether, achieving efficient recovery of isopropyl ether.
[0045] Step 4: The obtained isopropyl ether mixture is separated from acetone by an extractive distillation column, and then dehydrated and dried to obtain isopropyl ether. The extractant in the extractive distillation column is ethylene glycol. The theoretical number of plates in the extractive distillation column is 25, and the feed inlet is located at plate 15. The extractant feed inlet is located at plate 10. The reflux ratio of the extractive distillation column is 1.0.
[0046] Comparative Example A process system for separating and extracting isopropyl ether from bisphenol A wastewater includes the following steps: Step 1: Preheat the bisphenol A wastewater through a preheater; the bisphenol A wastewater comes from a chemical plant in Cangzhou and has the following composition: phenol 1822 kg / h, acetone 30 kg / h, isopropyl ether 3891 kg / h, water 138 kg / h, and heavy component impurities 191 kg / h.
[0047] Step 2: The preheated bisphenol A wastewater is transported to the distillation column for distillation; the material inlet is located at the 15th tray from the bottom.
[0048] Step 3: An isopropyl ether mixture is collected from the overhead gas outlet of the distillation column; the theoretical plate number of the distillation column is 28; the reflux ratio of the distillation column is 0.8. The isopropyl ether mixture contains 95.50% isopropyl ether, 0.82% acetone, 3.47% water, and 0.15% phenol. The phenol content is too high and does not meet the requirements for subsequent production.
[0049] The above description is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A process for separating and extracting isopropyl ether from bisphenol A wastewater, characterized in that, Includes the following steps: Step 1: Preheat the bisphenol A wastewater using a preheater; Step 2: The preheated bisphenol A wastewater is transported to a distillation column for distillation; Step 3: The isopropyl ether mixture is collected from the top gas outlet of the distillation column; Step 4: The obtained isopropyl ether mixture is separated from acetone by an extractive distillation column and then dehydrated and dried to obtain isopropyl ether.
2. The process for separating and extracting isopropyl ether from bisphenol A wastewater as described in claim 1, characterized in that, The process system includes a preheater, a distillation column, an extractive distillation column, and a storage tank; The preheater is connected to the material inlet of the distillation column; The overhead gas outlet of the distillation column is connected to the feed inlet of the extractive distillation column; the extractant outlet of the extractive distillation column is connected to the extractant feed inlet of the extractive distillation column. The side outlet of the extractive distillation column is connected to the storage tank.
3. The isopropyl ether separation and extraction process from bisphenol A wastewater as described in claim 2, characterized in that, The theoretical number of plates in the distillation column is 27-30.
4. The process for separating and extracting isopropyl ether from bisphenol A wastewater as described in claim 3, characterized in that, The material inlet is located at the 14th-16th tray from the bottom.
5. The process for separating and extracting isopropyl ether from bisphenol A wastewater as described in claim 4, characterized in that, The reflux ratio of the distillation column is 0.9-1.
0.
6. The process for separating and extracting isopropyl ether from bisphenol A wastewater as described in claim 2, characterized in that, The extractant in the extractive distillation column is ethylene glycol.
7. The process for separating and extracting isopropyl ether from bisphenol A wastewater as described in claim 6, characterized in that, The theoretical number of trays in the extractive distillation column is 20-40, and the feed inlet is located at tray 10-20.
8. The process for separating and extracting isopropyl ether from bisphenol A wastewater as described in claim 7, characterized in that, The extractant inlet is located at tray 3-10.
9. The process for separating and extracting isopropyl ether from bisphenol A wastewater as described in claim 7, characterized in that, The reflux ratio of the extractive distillation column is 0.8-2.
10. The process for separating and extracting isopropyl ether from bisphenol A wastewater as described in any one of claims 1-9, characterized in that, The phenol content in the obtained isopropyl ether is less than 0.05%.