Formaldehyde de-alcoholization unit

Abstract

This utility model discloses a formaldehyde deethanolination device, comprising a deethanolination tower, a preheater, a reboiler, a condenser, a reflux tank, a reflux pump, a feed pipeline, a reflux pipeline, and a first feeding pipeline. The feed pipeline is used to connect to the formaldehyde solution and is connected to the inlet of the preheater. The outlet of the preheater is connected to the inlet of the deethanolination tower. The top outlet of the deethanolination tower is connected to the inlet of the condenser. The outlet of the condenser is connected to the inlet of the reflux tank. The outlet of the reflux tank is connected to the inlet of the reflux pump. One end of the reflux pipeline and one end of the first feeding pipeline are both connected to the outlet of the reflux pump. This utility model can reduce steam consumption to save energy and improve methanol recovery rate, thereby reducing the residual methanol content in the formaldehyde solution and improving the stability during subsequent formaldehyde solution concentration.

Description

Technical Field

[0001] This utility model relates to a formaldehyde de-alcoholization device. Background Technology

[0002] Currently, dilute formaldehyde solution containing methanol, referred to as formaldehyde solution, can be extracted from drying absorption towers, multi-effect polymerization towers, and formaldehyde distillation towers. This extracted formaldehyde solution contains approximately 2% methanol. If directly treated as low-value wastewater, the methanol in the formaldehyde solution cannot be effectively recovered, resulting in methanol waste. Therefore, some companies choose to use distillation towers to treat this type of formaldehyde solution to recover the methanol. For example, Chinese patent CN1289453C discloses a method for removing methanol from formaldehyde-containing solutions based on distillation towers. However, recovering methanol from formaldehyde solutions using distillation towers not only consumes a large amount of steam, leading to high energy consumption, but also easily forms azeotropes, resulting in low separation efficiency. This leads to a low methanol recovery rate, less than 80%. The low methanol recovery rate also results in a high residual methanol content in the formaldehyde solution, which in turn affects the stability of subsequent formaldehyde solution concentration. Utility Model Content

[0003] The technical problem to be solved by this utility model is to overcome the defects of the prior art and provide a formaldehyde deethanoling device that can reduce the consumption of steam to save energy, improve the recovery rate of methanol, thereby reducing the residual methanol content in the formaldehyde solution and improving the stability of subsequent formaldehyde solution concentration.

[0004] To solve the above-mentioned technical problems, the technical solution of this utility model is: a formaldehyde de-alcoholization device, including a de-alcoholization tower, a preheater, a reboiler, a condenser, a reflux tank, a reflux pump, a feed pipeline, a reflux pipeline and a first feeding pipeline;

[0005] The feed pipe is used to connect to the formaldehyde solution and is connected to the feed inlet of the preheater;

[0006] The outlet of the preheater is connected to the inlet of the deethanolating tower;

[0007] The top outlet of the dealcoholization column is connected to the feed inlet of the condenser, and the outlet of the condenser is connected to the inlet of the reflux tank.

[0008] The outlet of the reflux tank is connected to the inlet of the reflux pump, one end of the reflux pipeline and one end of the first feed pipeline are both connected to the outlet of the reflux pump, and the other end of the reflux pipeline is connected to the reflux port of the dealcoholization tower.

[0009] The bottom of the dealcoholization column has a bottom section, the inlet of the reboiler is connected to the bottom of the bottom section, and the outlet of the reboiler is connected to the upper end of the bottom section.

[0010] Furthermore, the formaldehyde de-alcoholization device also includes a cooler and a second feeding pipeline; wherein, one end of the first feeding pipeline is connected to the outlet of the reflux pump, the other end of the first feeding pipeline is connected to the inlet of the cooler, and the outlet of the cooler is connected to the second feeding pipeline.

[0011] Furthermore, a flow meter and a regulating valve are respectively connected to the feed pipeline, the return pipeline and the second feeding pipeline.

[0012] Furthermore, the formaldehyde dehydrogenation device also includes a discharge pump and a discharge pipeline. The inlet of the discharge pump is connected to the liquid outlet at the bottom of the column bottom section, and the outlet of the discharge pump is connected to the discharge pipeline.

[0013] Furthermore, the formaldehyde deethanoling device also includes a first discharge branch pipe and a second discharge branch pipe. One end of the discharge pipeline is connected to the outlet of the discharge pump, and both the first discharge branch pipe and the second discharge branch pipe are connected to the other end of the discharge pipeline.

[0014] Furthermore, the formaldehyde de-alcoholization device also includes an alkali addition pipeline connected to the second discharge branch pipe and used to inject alkali solution into the second discharge branch pipe.

[0015] Furthermore, the formaldehyde deethanoling device also includes a controller;

[0016] A methanol concentration meter is connected to the bottom section of the tower.

[0017] The reboiler is connected to a steam supply pipeline, and a steam regulating valve is provided in the steam supply pipeline.

[0018] The methanol concentration meter is connected to the controller and is used to detect the concentration of methanol in the solution refluxed to the bottom section of the tower and send the concentration information to the controller;

[0019] The controller is connected to the steam regulating valve and is used to control the operation of the steam regulating valve based on the methanol concentration information measured by the methanol concentration meter.

[0020] Furthermore, a flow meter and a regulating valve are connected to the discharge pipeline.

[0021] Furthermore, two reflux pumps and two discharge pumps are connected in parallel.

[0022] Furthermore, the formaldehyde de-alcoholization device also includes a pressure balancing branch, one end of which is connected to the feed inlet of the condenser, and the other end of which is connected to the reflux tank.

[0023] The above technical solution involves using an inlet for receiving wastewater and an outlet for discharging wastewater. A formaldehyde solution, composed of methanol, water, and formaldehyde, is fed into the preheater. In the preheater, the formaldehyde solution exchanges heat with the wastewater, preheating it before flowing from the outlet into the inlet of the dealcoholization tower. Preheating the formaldehyde solution in the preheater fully utilizes the residual heat energy in the wastewater. The formaldehyde solution entering the dealcoholization tower exchanges heat with the vaporizing gas inside the tower, causing the methanol in the formaldehyde solution to evaporate into gas and flow upwards. The formaldehyde and water in the formaldehyde solution remain liquid and flow downwards back to the bottom section of the tower. The formaldehyde solution returning to the bottom section flows into the reboiler and exchanges heat with the steam in the reboiler to heat the formaldehyde solution. The heated formaldehyde solution then flows from the reboiler outlet back into the bottom section of the tower. Heating in the reboiler further evaporates the methanol, thus separating the remaining methanol. The reboiler inlet is used to receive high-temperature steam, and the reboiler outlet is used to discharge steam. The evaporated methanol gas flows from the top outlet of the dealcoholization tower into the condenser, where it is condensed and liquefied into liquid methanol before flowing into the reflux tank for storage. The condenser inlet is used to receive cooling water, and the condenser outlet is used to discharge cooling water. The reflux pump then pumps the methanol liquid from the reflux tank into the reflux pipeline and the first feed pipeline. The methanol liquid in the reflux pipeline flows back to the de-alcoholizing tower from the reflux port, while the methanol liquid in the first feed pipeline is discharged. The formaldehyde de-alcoholizing device of this embodiment not only optimizes energy utilization and reduces steam consumption throughout the process, thus saving energy, but also improves separation efficiency. It can efficiently separate and recover methanol from the formaldehyde solution, increasing the methanol recovery rate. Calculations show a recovery rate of over 95%, and the recovered methanol can be reused, reducing methanol consumption. Furthermore, the increased methanol recovery rate reduces the residual methanol content in the separated formaldehyde solution, thereby improving the stability of subsequent concentration of the separated formaldehyde solution and the production of paraformaldehyde, and reducing formaldehyde volatilization loss during the concentration process in the production of paraformaldehyde. Attached Figure Description

[0024] Figure 1 This is a process flow diagram of the formaldehyde deethanoling device of this utility model;

[0025] In the diagram: 1. Deethanolating tower; 2. Preheater; 3. Reboiler; 4. Condenser; 5. Reflux tank; 6. Reflux pump; 7. Feed line; 8. Reflux line; 9. First feed line; 10. Tower bottom section; 11. Cooler; 12. Second feed line; 13. Flow meter; 14. Control valve; 15. Discharge pump; 16. Discharge line; 17. First discharge branch; 18. Second discharge branch; 19. Alkali addition line; 20. Methanol concentration meter; 21. Pressure balance branch. Detailed Implementation

[0026] To make the contents of this utility model easier to understand, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0027] like Figure 1 As shown, a formaldehyde de-alcoholization device includes a de-alcoholization tower 1, a preheater 2, a reboiler 3, a condenser 4, a reflux tank 5, a reflux pump 6, a feed pipeline 7, a reflux pipeline 8, and a first feed pipeline 9.

[0028] The feed pipe 7 is used to connect to the formaldehyde solution and is connected to the feed inlet of the preheater 2;

[0029] The outlet of the preheater 2 is connected to the inlet of the deethanolating tower 1;

[0030] The top outlet of the dealcoholization tower 1 is connected to the feed inlet of the condenser 4, and the outlet of the condenser 4 is connected to the inlet of the reflux tank 5.

[0031] The outlet of the reflux tank 5 is connected to the inlet of the reflux pump 6. One end of the reflux pipeline 8 and one end of the first feed pipeline 9 are both connected to the outlet of the reflux pump 6. The other end of the reflux pipeline 8 is connected to the reflux port of the deethanolination tower 1.

[0032] The bottom of the dealcoholization column 1 has a bottom section 10, the inlet of the reboiler 3 is connected to the bottom of the bottom section 10, and the outlet of the reboiler 3 is connected to the upper end of the bottom section 10.

[0033] Specifically, the inlet of the preheater 2 is used to receive wastewater, and the outlet of the preheater 2 is used to discharge wastewater. The feed pipe 7 is used to receive formaldehyde solution, which consists of methanol, water, and formaldehyde. The formaldehyde solution flows into the preheater 2 from the feed pipe 7. In the preheater 2, the formaldehyde solution exchanges heat with the wastewater to preheat the formaldehyde solution, and then flows from the outlet of the preheater 2 into the inlet of the deethanolination tower 1. Preheating the formaldehyde solution through the preheater 2 can fully utilize the residual heat energy in the wastewater. The formaldehyde solution entering the dealcoholization tower 1 exchanges heat with the vaporized gas inside the tower, causing the methanol in the formaldehyde solution to evaporate into gas and flow upwards. The formaldehyde and water in the formaldehyde solution remain liquid and flow downwards back to the bottom section 10. The formaldehyde solution returning to the bottom section 10 flows into the reboiler 3 and exchanges heat with the steam in the reboiler 3 to heat the formaldehyde solution. The heated formaldehyde solution then flows from the outlet of the reboiler 3 back into the bottom section 10. Heating in the reboiler 3 further evaporates the methanol, thus separating the remaining methanol. The inlet of the reboiler 3 is used to receive high-temperature steam, and the outlet of the reboiler 3 is used to discharge steam. The evaporated methanol gas flows from the top outlet of the dealcoholization tower 1 into the condenser 4, where it is condensed and liquefied into liquid methanol before flowing into the reflux tank 5 for storage. The inlet of the condenser 4 is used to receive cooling water, and the outlet of the condenser 4 is used to discharge cooling water. Then, the reflux pump 6 pumps the methanol liquid in the reflux tank 5 to the reflux pipeline 8 and the first feed pipeline 9. The methanol liquid in the reflux pipeline 8 flows back to the de-alcoholizing tower 1 from the reflux port, and the methanol liquid in the first feed pipeline 9 can be discharged. The formaldehyde de-alcoholizing device of this embodiment not only optimizes energy utilization and reduces the amount of steam consumed in the entire process, thereby saving energy, but also improves separation efficiency, enabling efficient separation and recovery of methanol from the formaldehyde solution, increasing the methanol recovery rate. The calculated recovery rate is as high as 95% or more, and the recovered methanol can be reused, reducing methanol consumption. Furthermore, because the methanol recovery rate is improved, the residual methanol content in the separated formaldehyde solution is reduced, thereby improving the stability of subsequent concentration of the separated formaldehyde solution and the production of paraformaldehyde, and reducing the volatilization loss of formaldehyde during the concentration process in the production of paraformaldehyde.

[0034] like Figure 1As shown, the formaldehyde dehydrogenation device may further include a cooler 11 and a second feeding pipeline 12; wherein, one end of the first feeding pipeline 9 is connected to the outlet of the reflux pump 6, the other end of the first feeding pipeline 9 is connected to the inlet of the cooler 11, and the outlet of the cooler 11 is connected to the second feeding pipeline 12. Specifically, the inlet of the cooler 11 is used to receive cooling water, and the outlet of the cooler 11 is used to discharge cooling water. The methanol liquid in the first feeding pipeline 9 flows into the cooler 11 to exchange heat with the cooling water, thereby cooling the methanol liquid before it flows into the second feeding pipeline 12, and then is discharged into the methanol storage tank for storage.

[0035] like Figure 1 As shown, the formaldehyde deethanoling device may further include a discharge pump 15 and a discharge pipeline 16. The inlet of the discharge pump 15 is connected to the liquid outlet at the bottom of the bottom section of the tower 10, and the outlet of the discharge pump 15 is connected to the discharge pipeline 16.

[0036] like Figure 1 As shown, the formaldehyde deethanolination device may further include a first discharge branch pipe 17 and a second discharge branch pipe 18. One end of the discharge pipeline 16 is connected to the outlet of the discharge pump 15, and both the first discharge branch pipe 17 and the second discharge branch pipe 18 are connected to the other end of the discharge pipeline 16. Specifically, the discharge pump 15 is used to pump the formaldehyde solution in the bottom section 10 of the tower to the discharge pipeline 16. Then, a portion of the formaldehyde solution will be discharged from the first discharge branch pipe 17 to the formaldehyde storage tank for storage, and another portion of the formaldehyde solution will be discharged from the second discharge branch pipe 18 to the formaldehyde treatment equipment.

[0037] like Figure 1 As shown, the formaldehyde de-alcoholization device may further include an alkali addition pipeline 19 connected to the second discharge branch pipe 18 and used to inject alkali solution into the second discharge branch pipe 18; specifically, by injecting alkali solution into the second discharge branch pipe 18 so that the alkali solution flows into the formaldehyde treatment equipment along the second discharge branch pipe 18, the pH value in the formaldehyde treatment equipment can be controlled.

[0038] like Figure 1 As shown, the formaldehyde de-alcoholization device may further include a controller;

[0039] A methanol concentration meter 20 is connected to the bottom section 10 of the tower.

[0040] A steam supply pipeline is connected to the steam inlet of reboiler 3, and a steam regulating valve is installed in the steam supply pipeline.

[0041] The methanol concentration meter 20 is connected to the controller and is used to detect the concentration of methanol in the solution refluxed to the bottom section 10 of the tower and send the concentration information to the controller.

[0042] The controller is connected to the steam regulating valve and is used to control the operation of the steam regulating valve based on the methanol concentration information measured by the methanol concentration meter 20; specifically, when the methanol concentration in the solution in the bottom section 10 of the tower is above 0.2%, the controller controls the steam regulating valve to increase its opening.

[0043] like Figure 1 As shown, a flow meter 13 and a regulating valve 14 are respectively connected to the feed pipe 7, the return pipe 8, the second feed pipe 12 and the discharge pipe 16.

[0044] like Figure 1 As shown, there are two reflux pumps 6 connected in parallel, and two discharge pumps 15 are also connected in parallel.

[0045] like Figure 1 As shown, the formaldehyde de-alcoholization device may further include a pressure balancing branch 21, one end of which is connected to the feed inlet of the condenser 4, and the other end of which is connected to the reflux tank 5. The pressure balancing branch 21 can balance the gas pressure of the condenser 4 and the reflux tank 5.

[0046] In summary, the inlet of the preheater 2 is used to receive wastewater, and the outlet of the preheater 2 is used to discharge wastewater. The feed pipe 7 is used to receive formaldehyde solution, which consists of methanol, water, and formaldehyde. The formaldehyde solution flows into the preheater 2 from the feed pipe 7. In the preheater 2, the formaldehyde solution exchanges heat with the wastewater to preheat the formaldehyde solution, which then flows into the inlet of the dehydrogenation tower 1 from the outlet of the preheater 2. Preheating the formaldehyde solution through the preheater 2 can fully utilize the residual heat energy in the wastewater. The formaldehyde solution entering the dealcoholization tower 1 exchanges heat with the vaporized gas inside the tower, causing the methanol in the formaldehyde solution to evaporate into gas and flow upwards. The formaldehyde and water in the formaldehyde solution remain liquid and flow downwards back to the bottom section 10. The formaldehyde solution returning to the bottom section 10 flows into the reboiler 3 and exchanges heat with the steam in the reboiler 3 to heat the formaldehyde solution. The heated formaldehyde solution then flows from the outlet of the reboiler 3 back into the bottom section 10. Heating in the reboiler 3 further evaporates the methanol, thus separating the remaining methanol. The inlet of the reboiler 3 is used to receive high-temperature steam, and the outlet of the reboiler 3 is used to discharge steam. The evaporated methanol gas flows from the top outlet of the dealcoholization tower 1 into the condenser 4, where it is condensed and liquefied into liquid methanol before flowing into the reflux tank 5 for storage. The inlet of the condenser 4 is used to receive cooling water, and the outlet of the condenser 4 is used to discharge cooling water. Then, the reflux pump 6 pumps the methanol liquid in the reflux tank 5 to the reflux pipeline 8 and the first feed pipeline 9. The methanol liquid in the reflux pipeline 8 flows back to the de-alcoholizing tower 1 from the reflux port, and the methanol liquid in the first feed pipeline 9 can be discharged. The formaldehyde de-alcoholizing device of this embodiment not only optimizes energy utilization and reduces the amount of steam consumed in the entire process, thereby saving energy, but also improves separation efficiency, enabling efficient separation and recovery of methanol from the formaldehyde solution, increasing the methanol recovery rate. The calculated recovery rate is as high as 95% or more, and the recovered methanol can be reused, reducing methanol consumption. Furthermore, because the methanol recovery rate is improved, the residual methanol content in the separated formaldehyde solution is reduced, thereby improving the stability of subsequent concentration of the separated formaldehyde solution and the production of paraformaldehyde, and reducing the volatilization loss of formaldehyde during the concentration process in the production of paraformaldehyde.

[0047] The specific embodiments described above further illustrate the technical problems, technical solutions, and beneficial effects of this utility model. It should be understood that the above descriptions are merely specific embodiments of this utility model and are not intended to limit this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A formaldehyde de-alcoholization device, characterized in that, It includes a dealcoholization tower (1), a preheater (2), a reboiler (3), a condenser (4), a reflux tank (5), a reflux pump (6), a feed line (7), a reflux line (8), and a first feed line (9). The feed pipe (7) is used to connect to the formaldehyde solution and is connected to the feed port of the preheater (2); The outlet of the preheater (2) is connected to the inlet of the deethanolating tower (1); The top outlet of the dealcoholization tower (1) is connected to the feed inlet of the condenser (4), and the outlet of the condenser (4) is connected to the inlet of the reflux tank (5). The outlet of the reflux tank (5) is connected to the inlet of the reflux pump (6), one end of the reflux pipeline (8) and one end of the first feed pipeline (9) are both connected to the outlet of the reflux pump (6), and the other end of the reflux pipeline (8) is connected to the reflux port of the deethanolating tower (1). The bottom of the dealcoholization tower (1) has a bottom section (10), the feed inlet of the reboiler (3) is connected to the bottom of the bottom section (10), and the discharge outlet of the reboiler (3) is connected to the upper end of the bottom section (10).

2. The formaldehyde deethanoling apparatus according to claim 1, characterized in that, It also includes a cooler (11) and a second feeding pipeline (12); wherein one end of the first feeding pipeline (9) is connected to the outlet of the reflux pump (6), the other end of the first feeding pipeline (9) is connected to the inlet of the cooler (11), and the outlet of the cooler (11) is connected to the second feeding pipeline (12).

3. The formaldehyde deethanoling device according to claim 2, characterized in that, A flow meter (13) and a regulating valve (14) are respectively connected to the feed pipe (7), the return pipe (8) and the second feed pipe (12).

4. The formaldehyde deethanoling apparatus according to claim 1, characterized in that, It also includes a discharge pump (15) and a discharge pipeline (16). The inlet of the discharge pump (15) is connected to the liquid outlet at the bottom of the bottom section (10) of the tower, and the outlet of the discharge pump (15) is connected to the discharge pipeline (16).

5. The formaldehyde deethanoling apparatus according to claim 4, characterized in that, It also includes a first discharge branch pipe (17) and a second discharge branch pipe (18). One end of the discharge pipe (16) is connected to the outlet of the discharge pump (15), and the first discharge branch pipe (17) and the second discharge branch pipe (18) are both connected to the other end of the discharge pipe (16).

6. The formaldehyde de-alcoholization apparatus according to claim 5, characterized in that, It also includes an alkali addition pipeline (19) connected to the second discharge branch pipe (18) and used to inject alkali solution into the second discharge branch pipe (18).

7. The formaldehyde deethanoling apparatus according to claim 5, characterized in that, The discharge pipeline (16) is connected to a flow meter (13) and a regulating valve (14).

8. The formaldehyde deethanoling apparatus according to claim 5, characterized in that, Two reflux pumps (6) are connected in parallel, and two discharge pumps (15) are connected in parallel.

9. The formaldehyde deethanoling apparatus according to claim 1, characterized in that, It also includes the controller; A methanol concentration meter (20) is connected in the bottom section (10) of the tower. The reboiler (3) is connected to a steam supply pipeline, and a steam regulating valve is provided in the steam supply pipeline. The methanol concentration meter (20) is connected to the controller and is used to detect the concentration of methanol in the solution refluxed to the bottom section (10) of the tower and send the concentration information to the controller; The controller is connected to the steam regulating valve and is used to control the operation of the steam regulating valve based on the methanol concentration information measured by the methanol concentration meter (20).

10. The formaldehyde deethanoling apparatus according to claim 1, characterized in that, It also includes a pressure balancing branch (21), one end of which is connected to the feed inlet of the condenser (4), and the other end of which is connected to the reflux tank (5).

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