Device for removing total nitrogen in methanol water system
By using sulfuric acid additives and ion exchange resins in a methanol-water system, ammonium salts are generated and total nitrogen is adsorbed, thus solving the problem of amines circulating and affecting the catalyst, achieving catalyst protection and improved economic efficiency.
Patent Information
- Application Number
- CN202520337339.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-27
- Publication Date
- 2026-02-06
- Estimated Expiration
- 2035-02-27
AI Technical Summary
In the direct oxidation of propylene to propylene oxide technology, amines circulate in the methanol-water system, affecting the performance of the PO reaction catalyst and causing catalyst degradation or deactivation. Therefore, it is necessary to effectively remove total nitrogen.
Sulfuric acid is used as an auxiliary agent to react with amines before circulating methanol enters the methanol separation tower to generate ammonium salts which are discharged with the wastewater. Ion exchange resin is installed in the methanol system to adsorb and remove total nitrogen, thus protecting the PO reaction catalyst.
It effectively reduces the amine content in recycled methanol, protects the PO reaction catalyst, extends catalyst life, and improves the economic benefits of enterprises.
Smart Images
Figure CN223875065U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the technical field of total nitrogen removal in chemical production, especially to a total nitrogen removal device in methanol water system. BACKGROUND
[0002] In the field of propylene oxide production technology, although the chlorohydrination process and the co-oxidation process have been widely used, there are still many deficiencies. For example, the treatment of waste water and waste residue generated by the chlorohydrination process is difficult and requires large investment, and the by-products of the co-oxidation process cannot be treated. Therefore, the development of a green and simple process with less pollution and fewer by-products has become a focus. The direct oxidation method of propylene can solve the problems existing in the above processes and has many unique advantages, so it has become a hot spot for companies at home and abroad to compete in research and development in recent years. The HPPO technology for preparing propylene oxide by direct epoxidation of propylene is a new process technology, which is simple, has fewer by-products, and has high added value, and is currently being widely promoted.
[0003] The HPPO process uses methanol as a solvent, and amine substances need to be added as an aid to control the reaction and the quality of propylene oxide (PO) product in the system. Amine compounds will flow into the downstream unit methanol water system with the material, and if effective measures are not taken, the amine substances will circulate in the system with the methanol water solution, affecting the PO reaction and causing the catalyst to lose activity. Therefore, it is crucial to remove the total nitrogen in the methanol water system, especially the amine substances. SUMMARY
[0004] The utility model aims to provide a total nitrogen removal device in methanol water system, adopt sulfuric acid as an aid, before the circulating methanol enters the methanol separation tower, through the reaction of sulfuric acid and amine substance to generate ammonium salt and discharge with waste water, at the same time, in order to further control the content of amine substance in the material of circulating methanol to PO reactor, ion exchange resin is also arranged in the methanol system, through the resin adsorption to remove the total nitrogen in the methanol water solution, to protect the PO reaction catalyst.
[0005] The above technical purpose of the utility model is realized by the following technical scheme: a total nitrogen removal device in methanol water system, comprising
[0006] The mixer is used to mix sulfuric acid and circulating methanol.
[0007] The methanol separation tower is connected to the outlet of the mixer.
[0008] The resin bed is connected to the outlet of the methanol separation tower.
[0009] As a preferred, the inlet of the mixer is connected with a sulfuric acid pipeline and a circulating methanol pipeline, and the sulfuric acid pipeline is provided with a first flow meter.
[0010] Preferably, a first analyzer is arranged after the mixer.
[0011] Preferably, a reflux tank is further arranged, a feed end of the reflux tank is connected to a top of the methanol separation tower, and a discharge end of the reflux tank is connected with a reflux pump and connected to the methanol separation tower.
[0012] Preferably, a resin bed feed pipeline is further connected to the discharge end of the reflux pump, and the resin bed feed pipeline is connected to the resin bed.
[0013] Preferably, a second flow meter is arranged on the resin bed feed pipeline.
[0014] Preferably, the resin bed comprises resin bed a and resin bed b, and the resin bed a and the resin bed b are connected in series.
[0015] Preferably, a second analyzer is arranged before the resin bed a, and a first pressure gauge and a first differential pressure gauge are arranged on the resin bed a.
[0016] Preferably, a third analyzer is arranged between the resin bed a and the resin bed b.
[0017] Preferably, a second pressure gauge and a second differential pressure gauge are arranged on the resin bed b, a resin bed discharge pipeline is connected to a discharge end of the resin bed b, and a fourth analyzer is arranged on the resin bed discharge pipeline.
[0018] According to the utility model, the following beneficial effects are achieved:
[0019] The utility model discloses sulfuric acid as adjuvant, and before circulating methanol enters methanol separation tower, ammonium salt is generated with amine substance reaction of sulfuric acid and is discharged with waste water, and in order to further control the content of amine substance in the material of circulating methanol to PO reactor, ion exchange resin is further arranged in the methanol system, and total nitrogen in methanol aqueous solution is removed through ion exchange resin adsorption, to protect PO reaction catalyst. Through the method, amine substance in circulating methanol is reduced, PO reaction catalyst is effectively protected, the service life of catalyst is prolonged, and the economic benefit of enterprise is improved. BRIEF DESCRIPTION OF DRAWINGS
[0020] Figure 1 It is the schematic diagram of adsorption experiment in the embodiment;
[0021] Figure 2 It is the schematic diagram of the device in the embodiment.
[0022] In the figure, 1, sulfuric acid pipeline; 2, first flow meter; 3, circulating methanol pipeline; 4, mixer; 5, first analyzer; 6, methanol separation tower; 7, reflux tank; 8, waste water pipeline; 9, reflux pump; 10, resin bed feed pipeline; 11, second flow meter; 12, second analyzer; 13, first pressure gauge; 14, first differential pressure gauge; 15, resin bed a; 16, third analyzer; 17, resin bed b; 18, second pressure gauge; 19, second differential pressure gauge; 20, fourth analyzer; 21, resin bed discharge pipeline; 22, methanol tank; 23, metering pump; 24, resin bed; 25, receiving tank. DETAILED DESCRIPTION
[0023] The utility model will be further explained in detail below in combination with the drawings.
[0024] The specific embodiment is only the explanation of the utility model, and it is not the limitation of the utility model, and the person skilled in the art can make the modification without the creative contribution according to the need after reading the present specification, but as long as in the utility model's right claim range all receive the patent law's protection.
[0025] Embodiment: as shown in the figure, the methanol material with high total nitrogen in methanol tank 22 is transported to resin bed 24 by metering pump 23 with small flow, and the flow is about 400ml / h, and the material after resin adsorption treatment enters receiving tank 25.The resin adsorption experiment data are as shown in the following table. Figure 1
[0026]
[0027] Table 1 resin adsorption experiment data
[0028] Through the above experiment, it can be seen that the resin adsorption has obvious effect on total nitrogen in circulating methanol, and total nitrogen rapidly decreases, and the material PH also decreases simultaneously.
[0029] As shown in the figure, the methanol material with high total nitrogen in methanol tank 22 is transported to resin bed 24 by metering pump 23 with small flow, and the flow is about 400ml / h, and the material after resin adsorption treatment enters receiving tank 25.The resin adsorption experiment data are as shown in the following table. Figure 2 As shown, the device mainly includes a mixer 4, a methanol separation tower 6, a reflux tank 7, a reflux pump 9, a resin bed a 15, a resin bed b 17, and related pipelines, valves, instruments, etc. The circulating methanol in the system is transported to the mixer 4 through the circulating methanol pipeline 3. The sulfuric acid is transported to the mixer 4 through the sulfuric acid pipeline 1 and mixed with the circulating methanol in the system; the sulfuric acid is controlled by the first flow meter 2 to control the amount of sulfuric acid added. The material mixed with the circulating methanol is transported to the methanol separation tower 6 through the pipeline. The overhead material of the methanol separation tower 6 is transported to the reflux tank 7 through the pipeline. The material in the reflux tank 7 is transported by the reflux pump 9, part of which is used as reflux of the methanol separation tower 6, and the other part enters the resin bed a 15 and the resin bed b 17 through the resin bed feed pipeline 10. The tower bottom material of the methanol separation tower 6 is transported to the downstream for treatment through the wastewater pipeline 8. The methanol material entering the resin bed a 15 and the resin bed b 17 is controlled by the second flow meter 11 to control the flow; the resin bed a 15 and the resin bed b 17 are connected in series. The material after total nitrogen removal through the resin bed a 15 and the resin bed b 17 is transported to the PO reactor for circulation through the resin bed discharge pipeline 21.
[0030] Specifically, the working mode of removing total nitrogen in the methanol water system is as follows: the circulating methanol in the system is transported to the mixer 4 through the circulating methanol pipeline 3. The sulfuric acid is transported to the mixer 4 through the sulfuric acid pipeline 1 and mixed with the circulating methanol in the system; the sulfuric acid is controlled by the first flow meter 2 to control the amount of sulfuric acid added; the first analyzer 5 is arranged after the mixer 4 to monitor the PH value and total nitrogen content in the material, and the PH value is controlled to be 3-5. The material mixed by the sulfuric acid and the circulating methanol is transported to the methanol separation tower 6 through the pipeline. The methanol material separated from the top of the methanol separation tower 6 is transported to the reflux tank 7 through the pipeline. The material in the reflux tank 7 is transported by the reflux pump 9, part of which is used as reflux of the methanol separation tower 6, and the other part enters the resin bed a 15 and the resin bed b 17 through the resin bed feed pipeline 10. The tower kettle material of the methanol separation tower 6 is transported to the downstream for treatment through the wastewater pipeline 8. The methanol material entering the resin bed a 15 and the resin bed b 17 is controlled by the second flow meter 11 to control the flow; the resin bed a 15 and the resin bed b 17 are connected in series. The second analyzer 12 is arranged for monitoring the PH value and total nitrogen content in the material of the resin bed a 15 feed, and the feed PH value is controlled to be 5.5-8.5; the third analyzer 16 is arranged at the outlet of the resin bed a to monitor the PH value and total nitrogen content of the material, and the PH value is controlled to be below 6.5; the first pressure gauge 13 and the differential pressure gauge PD1 14 are arranged for the resin bed a 15, the pressure of the resin bed a 15 is controlled to be 0.5-0.6 MPag, and the bed layer differential pressure is controlled to be below 0.2 MPag. The fourth analyzer 20 is arranged at the outlet of the resin bed b to monitor the PH value and total nitrogen content of the material, and the PH value is controlled to be below 6.5; the second pressure gauge 18 and the differential pressure gauge PD2 19 are arranged for the resin bed b 17, the pressure of the resin bed b 17 is controlled to be 0.5-0.6 MPag, and the bed layer differential pressure is controlled to be below 0.2 MPag. The material after removing total nitrogen by the resin bed a 15 and the resin bed b 17 is transported to the PO reactor for circulation through the resin bed discharge pipeline 21.
[0031] Wherein, the circulating methanol pipeline 3 flow is about 200-240 t / h, the sulfuric acid pipeline 1 sulfuric acid flow is about 180-220 kg / h, after mixing by the mixer 4, it enters the methanol separation tower 6 for separation, the methanol from the top enters the reflux tank 7, is transported to the ion exchanger a 15 by the reflux pump 9, the feed flow is about 120-160 t / h, and the circulating methanol enters the downstream unit after being adsorbed by the resin bed a 15 and the resin bed b 17. The operation data is shown in Table 2.
[0032]
[0033] Table 2 operation data
[0034] As can be seen from Table 2, after the mixed reaction of the circulating methanol by sulfuric acid, the total nitrogen will be significantly reduced by a part, and sulfuric acid can remove a part of the total nitrogen. After adsorption by ion exchange resin, the total nitrogen at the outlet of the resin bed is greatly reduced and basically removed, and the total nitrogen at the outlet of the resin bed b is less than 1.0 ppm. However, the adsorption capacity of a single resin bed is limited, and the time is short, and after 72 h, the saturation is basically reached, and the total nitrogen and PH at the outlet of the resin bed a are greatly increased. After adsorption by the resin bed b, the use of two resin beds in series can effectively ensure that the total nitrogen in the circulating methanol material can be effectively removed, and switching treatment and resin replacement can be carried out.
Claims
1. A device for removing total nitrogen from a methanol water system, characterized by, Comprising a mixer (4) for mixing sulfuric acid and recycled methanol; a methanol separation column (6) having its feed end connected to the discharge of the mixer (4); a resin bed having its feed connected to the discharge of the methanol separation column (6).
2. The device for removing total nitrogen in a methanol water system according to claim 1, characterized in that, The feed end of the mixer (4) is connected to a sulfuric acid line (1) and a recycled methanol line (3), the sulfuric acid line (1) being provided with a first flow meter (2).
3. The device for removing total nitrogen in a methanol water system according to claim 1, characterized in that, The mixer (4) is followed by a first analyzer (5).
4. The device for removing total nitrogen in a methanol water system according to claim 1, characterized in that, Also included is a reflux tank (7), the top of the methanol separation column (6) being connected to the feed end of the reflux tank (7), the discharge end of the reflux tank (7) being connected to a reflux pump (9) and to the methanol separation column (6).
5. A device for removing total nitrogen from a methanol water system according to claim 4, characterized in that The discharge of the reflux pump (9) is also connected to a resin bed feed line (10) which is connected to the resin bed.
6. The device for removing total nitrogen in a methanol water system according to claim 5, characterized in that, The resin bed feed line (10) is provided with a second flow meter (11).
7. The device for removing total nitrogen in a methanol water system according to claim 1, characterized in that, The resin bed comprises a resin bed a (15) and a resin bed b (17) which are connected in series.
8. The device for removing total nitrogen in a methanol water system according to claim 7, characterized in that, The resin bed a (15) is preceded by a second analyzer (12) and is provided with a first pressure gauge (13) and a first differential pressure gauge (14).
9. The device for removing total nitrogen in a methanol water system according to claim 7, characterized in that, Between the resin bed a (15) and the resin bed b (17) is a third analyzer (16).
10. The device for removing total nitrogen from a methanol water system according to claim 1, characterized in that, The resin bed b (17) is provided with a second pressure gauge (18) and a second differential pressure gauge (19), the discharge end of the resin bed b (17) being connected to a resin bed discharge line (21) which is provided with a fourth analyzer (20).