Desulfurization process system of methyl tert-butyl ether crude product
By adding light diesel as a solvent during the distillation process of methyl tert-butyl ether crude product and using diesel hydrodesulfurization device to convert sulfide, the problem of coking at the bottom of the distillation tower is solved, and economical desulfurization of methyl tert-butyl ether crude product and efficient self-digestion of hydrogen sulfide are achieved.
Patent Information
- Application Number
- CN202420389329.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-01
- Publication Date
- 2025-02-28
- Estimated Expiration
- 2034-03-01
AI Technical Summary
The prior art is prone to coking problems of the distillation tower bottom reboiler during the distillation process of methyl tert-butyl ether (MTBE) crude product, which affects the normal operation of the device, and the price of anti-coking agents is high.
A desulfurization process system using a crude methyl tert-butyl ether product is used. By adding light diesel to the distillation tower as a solvent, the substances other than sulfur dioxide are cut by boiling point difference, and are sent to the diesel hydrodesulfurization device through recombinant condensation to convert high temperature and high pressure into hydrogen sulfide, which is self-digested.
The economical desulfurization of methyl tert-butyl ether crude product is achieved, reducing the desulfurization cost and avoiding secondary pollution.
Smart Images
Figure CN222534103U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of desulfurization technology, in particular to a desulfurization process system for a crude methyl tert-butyl ether product. Background Art
[0002] The reduction of sulfur content in gasoline quality upgrade is one of the important factors. At the National V stage, the sulfur content in gasoline is required to be reduced to below 10μg / g. Methyl tert-butyl ether (MTBE) is an important blending component of gasoline, and the amount of MTBE added is generally between 10 and 20%. In order not to affect the blending of gasoline, refineries generally require that the sulfur content in MTBE products be purified to below 10μg / g.
[0003] In order to meet this requirement, refineries generally use distillation technology to purify the crude MTBE product produced from the MTBE unit, but the reboiler at the bottom of the distillation tower will cause coking, which affects the normal operation of the unit. To solve this problem, the existing technology has developed a coking retarder, which is added to the bottom of the distillation tower to prevent coking. However, the price of the coking retarder is high, and the annual addition cost is more than one million yuan. Utility Model Content
[0004] In view of the above problems, the utility model proposes a desulfurization process system for a crude methyl tert-butyl ether product, so as to achieve the economic desulfurization of the crude methyl tert-butyl ether product.
[0005] To achieve the above purpose, the following technical scheme is adopted: a desulfurization process system for crude methyl tert-butyl ether product, comprising a feed main line, a distillation tower, a tower top cooler, a reflux tank, a reboiler and a heavy component cooler, the feed end of the feed main line is connected to a crude product feed pipeline and a light diesel feed pipeline, the discharge end is connected from the middle tray position of the distillation tower, the tower top of the distillation tower is connected to the tower top cooler, the tower top cooler is connected to the liquid inlet of the reflux tank, the liquid outlet of the reflux tank is connected back to the tower top of the distillation tower through a reflux pump, and the other part is connected to the refined product discharge pipeline, a heat bypass is added between the tower top of the distillation tower and the reflux tank for control; a liquid level line is preset in the distillation tower, the bottom discharge port of the reboiler is connected to the bottom of the distillation tower, the top liquid injection port of the reboiler is connected to the top of the liquid level line of the distillation tower, the bottom of the distillation tower is also connected to the heavy component cooler through a heavy component external delivery pump, and the heavy component cooler is externally connected to a diesel hydrodesulfurization device.
[0006] Furthermore, a sulfur slurry level control line is arranged on the sulfur slurry stirring tank and a sulfur slurry level controller is arranged at a corresponding position, a water phase level control line and an oil phase level control line are arranged on the refined sulfur kettle and a water phase level controller and an oil phase level controller are arranged correspondingly, the sulfur slurry level controller is connected to the control valve on the salt discharge pipeline and controls its opening and closing, the water phase level controller is connected to the control valve on the reflux hot water pipeline and controls its opening and closing, and the oil phase level controller is connected to the control valve on the oil discharge pipeline and controls its opening and closing.
[0007] Furthermore, the amount of light diesel added to the distillation tower is 0.1%-0.2% of the crude methyl tert-butyl ether product.
[0008] Furthermore, the initial boiling point of the light diesel in the distillation tower is 239°C, and the final boiling point is 306°C.
[0009] Furthermore, the distillation tower uses 40-50 floating valve trays, and the reflux ratio is controlled at 0.5-0.8.
[0010] Furthermore, the reflux tank top pressure is controlled at 0.02MPag-0.05MPag.
[0011] Furthermore, the steam pressure of the reboiler heating source is 0.5 MPag.
[0012] Beneficial effects of the utility model: The utility model utilizes the difference in boiling points of the components in the crude raw material in the distillation tower, cuts all the substances in the tower except sulfur dioxide into the top of the tower, and the distilled gas phase enters the reflux tank after condensation, a part of which is output as a refined product, and the other part returns to the distillation tower; the auxiliary material uses light diesel as a solvent to make up for the defect that heat cannot be transferred due to too low sulfide content at the bottom of the tower. The sulfide and light diesel at the bottom of the tower are condensed by the heavy components and sent to the existing diesel hydrodesulfurization device of the refinery to be converted into hydrogen sulfide at high temperature and high pressure, and then digested by itself. This process system uses light diesel that is easily obtained in the refinery as an auxiliary material, and the generated hydrogen sulfide is digested in the refinery's own device, which greatly reduces the desulfurization cost of methyl tert-butyl ether. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 Schematic diagram of an embodiment of the present invention.
[0014] As shown in the figure: 1. Main feed line; 2. Distillation tower; 3. Top cooler; 4. Reflux tank; 5. Reboiler; 6. Heavy component cooler; 7. Reflux pump; 8. Heavy component delivery pump; 100. Crude product feed pipeline; 200. Light diesel feed pipeline; 300. Refined product discharge pipeline; 400. Diesel hydrodesulfurization unit; 500. Thermal bypass. DETAILED DESCRIPTION
[0015] Example 1
[0016] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.
[0017] like Figure 1 A desulfurization process system for a crude methyl tert-butyl ether product is provided, the system comprising a main feed line 1, a distillation tower 2, a tower top cooler 3, a reflux tank 4, a reboiler 5 and a heavy component cooler 6, and external pipelines and equipment include a crude product feed pipeline 100, a light diesel feed pipeline 200, a product discharge pipeline 300 and a diesel hydrodesulfurization device 400.
[0018] The feed end of the main feed line 1 is connected to the crude product feed line 100 and the light diesel feed line 200, and the discharge end is connected from the middle tray position of the distillation tower 2. The top of the distillation tower 2 is connected to the top cooler 3, and the top cooler 3 is connected to the liquid inlet of the reflux tank 4. The liquid outlet of the reflux tank 4 is connected back to the top of the distillation tower 2 through a reflux pump 7, and the other part is connected to the refined product discharge line 300. A heat bypass 500 is added between the top of the distillation tower 2 and the reflux tank 4 for control; a liquid level line is preset in the distillation tower 2, the bottom discharge port of the reboiler 5 is connected to the bottom of the distillation tower 2, and the top liquid injection port of the reboiler 5 is connected to the liquid level line above the distillation tower 2. The bottom of the distillation tower 2 is also connected to the heavy component cooler 6 through the heavy component external pump 8, and the heavy component cooler 6 is connected to the diesel hydrodesulfurization device 400.
[0019] In this process system, the crude methyl tert-butyl ether product S1 in the crude product feed pipeline 100 and the light diesel oil S2 in the light diesel oil feed pipeline 200 are mixed in the main feed pipeline 1 and injected into the distillation tower 2. The bottom of the distillation tower 2 is heated by a reboiler 5. The steam pressure of the heating source of the reboiler 5 is 0.5MPag. The amount of light diesel oil S2 added is 0.1%-0.2% of the crude methyl tert-butyl ether product S1. The initial distillation point of the light diesel oil S2 in the distillation tower 2 is 239°C and the final distillation point is 306°C. The mixed material enters from the middle of the tower plate of the distillation tower 2. The tower top pressure is controlled at a slightly positive pressure. The distillation tower 2 uses 40-50 floating valve tower plates. The gas phase at the top of the tower is After cooling, methyl tert-butyl ether enters the reflux tank 4, and the top pressure of the reflux tank 4 is controlled at 0.02MPag-0.05MPag. A part of the liquid in the reflux tank 4 refluxes into the top of the distillation tower 2, and the reflux ratio is controlled at 0.5-0.8. The other part produces refined methyl tert-butyl ether S3 from the refined product discharge pipeline 300; the bottom of the distillation tower 2 is a gasified sulfide and light diesel mixture S4, which is boosted by the heavy component delivery pump 8 and then cooled by the heavy component cooler 6 and then enters the diesel hydrodesulfurization device 400. The sulfide and light diesel mixture S4 can be desulfurized after being converted into hydrogen sulfide at high temperature and high pressure in the diesel hydrodesulfurization device 400 without causing secondary pollution.
[0020] The working basis of this embodiment is that in the crude product S1 of methyl tert-butyl ether, the content of methyl tert-butyl ether (boiling point 55.2°C) is usually more than 98% (wt), and the impurities contained mainly include: isobutane (boiling point -11.72°C), 1-butene (boiling point -6.25°C), cis-butylene (boiling point 3.72°C), trans-butene (boiling point 0.88°C), normal butane (boiling point -0.5°C), methyl sec-butyl ether (boiling point 59°C), tert-butyl alcohol (boiling point 82.42°C), methanol (boiling point 64.7°C) and sulfide. Sulfide mainly exists in the form of dimethyl disulfide (boiling point 109.74°C), and its content is usually more than 90% of the total sulfide, and the boiling points of other types of sulfide are higher. By taking advantage of the difference in boiling points, the distillation method can be used to cut all substances except disulfide into the top of the distillation tower, and the bottom of the tower is sulfide. Although this can be achieved, the sulfide content in the raw material is too low, resulting in no bottom material at the bottom of the tower, and heat cannot be transferred at the bottom of the tower. Especially at the start of operation, the liquid level cannot be established at the bottom of the tower for a long time. Therefore, a solvent needs to be added to achieve heat transfer. At the same time, this solvent is easy to obtain in the refinery. After comprehensive consideration, light diesel S2 is selected as this solvent.
[0021] Obviously, the described embodiments are only some embodiments of the utility model, not all embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
Claims
1. A desulfurization process system for crude methyl tert-butyl ether product, characterized in that: The invention comprises a main feed line (1), a distillation tower (2), a tower top cooler (3), a reflux tank (4), a reboiler (5) and a heavy component cooler (6). The feed end of the main feed line (1) is connected to a crude product feed line (100) and a light diesel feed line (200). The discharge end is connected to a tray in the middle of the distillation tower (2). The top of the distillation tower (2) is connected to the tower top cooler (3). The tower top cooler (3) is connected to a liquid inlet of a reflux tank (4). The liquid outlet of the reflux tank (4) is connected back to the distillation tower (5) through a reflux pump (7). 2), and the other part is connected to the top of the tower (2), and the other part is connected to the refined product discharge pipeline (300); a heat bypass (500) is added between the top of the distillation tower (2) and the reflux tank (4) for control; a liquid level line is preset in the distillation tower (2), the bottom discharge port of the reboiler (5) is connected to the bottom of the distillation tower (2), and the top injection port of the reboiler (5) is connected to the top of the liquid level line of the distillation tower (2); the bottom of the distillation tower (2) is also connected to the heavy component cooler (6) through the heavy component external delivery pump (8), and the heavy component cooler (6) is externally connected to the diesel hydrodesulfurization device (400).
2. The desulfurization process system according to claim 1, characterized in that: The amount of light diesel added to the distillation tower (2) is 0.1%-0.2% of the crude methyl tert-butyl ether product.
3. The desulfurization process system according to claim 2, characterized in that: The initial distillation point of the light diesel in the distillation tower (2) is 239°C, and the final distillation point is 306°C.
4. The desulfurization process system according to claim 3, characterized in that: The distillation tower (2) uses 40-50 floating valve trays, and the reflux ratio is controlled at 0.5-0.
8.
5. The desulfurization process system according to claim 4, characterized in that: The top pressure of the reflux tank (4) is controlled at 0.02MPag-0.05MPag.
6. The desulfurization process system according to claim 5, characterized in that: The steam pressure of the heating source of the reboiler (5) is 0.5 MPag.