Device for increasing feeding temperature of pre-rectifying tower by using refined methanol product
By modifying the methanol distillation unit, the methanol in the pressurized tower reflux tank is pre-cooled and then cooled, and the bypass preheating medium is sent to the condensate main pipe. This solves the problems of low feed temperature and high energy consumption in the pre-distillation tower, reduces methanol product loss and energy consumption, and achieves significant environmental pollution control results.
Patent Information
- Application Number
- CN202423029022.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-09
- Publication Date
- 2025-11-21
- Estimated Expiration
- 2034-12-09
AI Technical Summary
In the methanol distillation process, the low feed temperature of the pre-distillation tower leads to a large amount of volatilization, high energy consumption, and serious product loss and environmental pollution, especially when the temperature changes.
By modifying the equipment, the methanol at the bottom of the pressurized tower reflux tank is first pre-cooled by the crude methanol preheater in the pre-tower, then cooled by the refined methanol cooler, and then sent to the intermediate storage tank. At the same time, the condensate of the preheating medium vapor originally used by the crude methanol preheater in the pre-tower is bypassed to the condensate main pipe, and the refined methanol product is used to increase the feed temperature of the pre-distillation tower.
This effectively reduced methanol product losses and energy consumption, decreased volatile organic compound emissions, and improved the operational stability and economic benefits of the plant.
Smart Images
Figure CN223570050U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the field of methanol rectification, especially to a device for improving the feed temperature of a pre-distillation column by using refined methanol products. BACKGROUND
[0002] The principle of methanol rectification is to separate methanol from a mixture by using the different boiling points of the components in the crude methanol, partially vaporizing the liquid mixture containing methanol multiple times in the methanol rectification column, and partially condensing the gas mixture multiple times, thereby obtaining refined methanol of the required quality.
[0003] The composition of the rectification system mainly consists of a rectification column, a column kettle heater, a column top condenser, and other auxiliary equipment. The rectification column is divided into upper and lower sections by a feeding plate. The upper section is called the rectification section, and the lower section is called the stripping section. The main function of the rectification section is to concentrate volatile components to increase the concentration of volatile components in the distillate (column top product). The main function of the stripping section is to concentrate non-volatile components to obtain a residue with a high purity of non-volatile components at the bottom of the kettle.
[0004] Currently, in the 4-column rectification process, crude methanol is first preheated by a crude methanol preheater before entering the pre-distillation column. The preheating is usually performed using steam condensate from the pre-column reboiler, and then the preheated crude methanol enters the pre-distillation column. The refined methanol product from the pressurized column reflux tank is cooled by a circulating water cooler and then directly sent to the product storage tank.
[0005] In actual production, the following problems exist: In winter, the methanol product from the rectification pressurized column is cooled by a circulating water cooler and has a temperature of about 40-42℃ (the circulating water temperature is about 26℃). After mixing with the methanol product from the rectification atmospheric column (temperature: about 37-40℃), the mixture directly enters the methanol intermediate storage tank. Due to the high temperature, the amount of volatilized methanol from the storage tank is relatively large, which may cause the pressure in the storage tank to rise and other risks. In summer, during normal production, the ambient temperature and the circulating water temperature increase by about 3-6℃, which causes the temperature of the mixture of the methanol products from the pressurized column and the atmospheric column to rise by about 5-8℃, resulting in a larger amount of volatilized methanol, which may cause the pressure in the storage tank to rise and other risks. At the same time, methanol vapor is discharged from the breather valve at the top of the storage tank and directly enters the air, causing methanol loss and environmental pollution.
[0006] After the pre-distillation column feed is preheated by the steam condensate from the pre-column reboiler, the temperature is generally about 32-35℃, while the design temperature of the feed is about 72℃. To meet the process requirements, the amount of heating steam must be increased, but the effect is not obvious. At the same time, increasing the amount of steam will increase the energy consumption of the rectification system. SUMMARY
[0007] The utility model discloses a method for raising pre rectification tower feed temperature by utilizing produced refined methanol, which can effectively solve the problems of high temperature of rectification produced product, large volatile amount, low pre rectification tower feed temperature and high energy consumption in the production process, and has good practical value for reducing methanol rectification product loss, reducing cost and increasing efficiency of the device and VOCS treatment.
[0008] To solve the above problems, the utility model provides a device for raising pre rectification tower feed temperature by utilizing refined methanol product, which is composed of a pressurized reflux tank, a pre rectification tower preheater, a pre rectification tower, a reboiler, a refined methanol product cooler and a reflux pump; the pre rectification tower preheater is connected with the pre rectification tower, the pre rectification tower bottom is provided with the reboiler, the reboiler condensate outlet is connected with the fourth shut -off valve and the fifth shut -off valve, the fifth shut -off valve is connected with the condensate liquid inlet of the pre rectification tower preheater, the fourth shut -off valve is connected with the condensate liquid discharge outlet, and the condensate liquid outlet of the pre rectification tower preheater is connected with the condensate liquid discharge outlet through the sixth shut -off valve; the pressurized reflux tank outlet is connected with the reflux pump, the first shut -off valve and the second shut -off valve; the first shut -off valve is connected with the condensate liquid inlet of the pre rectification tower preheater, the second shut -off valve is connected with the refined methanol product cooler, and the condensate liquid outlet of the pre rectification tower preheater is connected with the refined methanol product cooler through the third shut -off valve. Opening the first shut -off valve, closing the second shut -off valve, opening the third shut -off valve, opening the fourth shut -off valve, closing the fifth shut -off valve and the sixth shut -off valve, the refined methanol enters the condensate liquid inlet of the pre rectification tower preheater through the first shut -off valve, preheats the pre rectification tower preheater, and then enters the refined methanol product cooler from the condensate liquid outlet of the pre rectification tower preheater through the third shut -off valve.
[0009] Further, the sixth shut -off valve is provided with an 8-shaped blind plate on the side of the condensate liquid outlet of the pre rectification tower preheater, and the fifth shut -off valve is provided with an 8-shaped blind plate on the side of the condensate liquid inlet of the pre rectification tower preheater. The 8-shaped blind plate can increase the shut -off effect of the fifth shut -off valve and the sixth shut -off valve.
[0010] The utility model discloses a bottom methanol of pressurized reflux tank is first cooled after preheating through pre tower crude methanol preheater, then is cooled through refined methanol cooler, finally is sent to methanol intermediate storage tank, and the preheating medium (the steam condensate liquid of pre rectification tower reboiler) originally used to pre tower crude methanol preheater is directly sent to condensate liquid main pipe through pre tower preheater bypass. Effectively solve the problems of high temperature of methanol product, large loss, environmental pollution, low pre rectification tower feed temperature and high energy consumption, and achieve two goals at one stroke. The utility model has the characteristics of simple transformation, stable operation and strong practicability, and has very beneficial value for reducing energy consumption in the rectification production process, reducing methanol rectification product loss, reducing cost and increasing efficiency of the device, VOCS treatment and other practical problems. DRAWINGS
[0011] Figure 1It is the device structure schematic diagram of using refined methanol product to promote pre rectification tower feed temperature.
[0012] Reference signs:
[0013] 1: first cut-off valve; 2: second cut-off valve; 3: pressurized tank reflux tank; 4: pre rectification tower preheater; 5: pre rectification tower; 6: reboiler; 7: refined methanol product cooler; 8: reflux pump; 9: third cut-off valve; 10: fourth cut-off valve; 11: fifth cut-off valve; 12: sixth cut-off valve. DETAILED DESCRIPTION
[0014] To make the purpose, technical scheme and advantages of the utility model more clear and intelligible, the utility model is further explained in detail below in combination with specific implementation manners and with reference to the drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the utility model. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the utility model.
[0015] As Figure 1 shown, a device for using refined methanol product to promote pre rectification tower feed temperature is provided, which is composed of a pressurized tank reflux tank 3, a pre rectification tower preheater 4, a pre rectification tower 5, a reboiler 6, a refined methanol product cooler 7 and a reflux pump 8. The pre rectification tower preheater 4 is connected with the pre rectification tower 5, the pre rectification tower 5 is provided with the reboiler 6 at the bottom, the reboiler 6 is connected with the fourth cut-off valve 10 and the fifth cut-off valve 11 at the condensate liquid outlet, the fifth cut-off valve 11 is connected with the condensate liquid inlet of the pre rectification tower preheater 4, the fourth cut-off valve 10 is connected with the condensate liquid discharge outlet, the condensate liquid outlet of the pre rectification tower preheater 4 is connected with the condensate liquid discharge outlet through the sixth cut-off valve 12. The outlet of the pressurized tank reflux tank 3 is connected with the reflux pump 8, the first cut-off valve 1 and the second cut-off valve 2. The first cut-off valve 1 is connected with the condensate liquid inlet of the pre rectification tower preheater 4, the second cut-off valve 2 is connected with the refined methanol product cooler 7, and the condensate liquid outlet of the pre rectification tower preheater 4 is connected with the refined methanol product cooler 7 through the third cut-off valve 9. Open the first cut-off valve 1, close the second cut-off valve 2, open the third cut-off valve 9, open the fourth cut-off valve 10, close the fifth cut-off valve 11 and the sixth cut-off valve 12, and the refined methanol enters the condensate liquid inlet of the pre rectification tower preheater 4 through the first cut-off valve 1, preheats the pre rectification tower preheater 4, and then enters the refined methanol product cooler 7 from the condensate liquid outlet of the pre rectification tower preheater 4 through the third cut-off valve 9.
[0016] The sixth cut-off valve 12 is provided with an 8-shaped blind plate on the side of the condensate liquid outlet of the pre rectification tower preheater, and the fifth cut-off valve 11 is provided with an 8-shaped blind plate on the side of the condensate liquid inlet of the pre rectification tower preheater. The 8-shaped blind plate can increase the cut-off effect of the fifth cut-off valve and the sixth cut-off valve.
[0017] It should be understood that the above specific embodiments of the present application are only used for illustrative or explanatory purposes of the principles of the present application, and do not constitute a limitation on the present application. Therefore, any modification, equivalent replacement, improvement, etc. made without departing from the spirit and scope of the present application shall be included in the protection scope of the present application. In addition, the appended claims of the present application are intended to cover all changes and modifications falling within the scope and boundaries of the appended claims, or the equivalent forms of such scope and boundaries.
Claims
1. An apparatus for raising the feed temperature of a pre-distillation column using refined methanol products, characterized in that, It consists of a pressurized tower reflux tank, a pre-distillation tower preheater, a pre-distillation tower, a reboiler, a refined methanol product cooler, and a reflux pump. The pre-distillation tower preheater is connected to the pre-distillation tower. A reboiler is installed at the bottom of the pre-distillation tower. The condensate outlet of the reboiler is connected to a fourth and a fifth shut-off valve. The fifth shut-off valve is connected to the condensate inlet of the pre-distillation tower preheater. The fourth shut-off valve is connected to the condensate outlet. The condensate outlet of the pre-distillation tower preheater is connected to the condensate outlet through a sixth shut-off valve. The outlet of the pressurized tower reflux tank is connected to the reflux pump, a first shut-off valve, and a second shut-off valve. The first shut-off valve is connected to the condensate inlet of the pre-distillation tower preheater. The second shut-off valve is connected to the refined methanol product cooler. The condensate outlet of the pre-distillation tower preheater is connected to the refined methanol product cooler through a third shut-off valve.
2. The apparatus for raising the feed temperature of the pre-distillation column using refined methanol products according to claim 1, characterized in that, The sixth shut-off valve is equipped with a figure-eight blind flange on the side near the condensate outlet of the pre-distillation column preheater, and the fifth shut-off valve is equipped with a figure-eight blind flange on the side near the condensate inlet of the pre-distillation column preheater.