Production system for safely preparing formaldehyde by adopting silver method

Abstract

The utility model relates to the technical field of formaldehyde production, in particular to a production system for safely producing formaldehyde by adopting a silver method, which is characterized in that a fan is connected with a preheater through a pipeline, a methanol storage tank, a methanol evaporator, a methanol reboiler and the preheater are sequentially connected through pipelines, and a steam distributor is respectively connected with a jacket of the methanol evaporator and the preheater; the steam distributor is connected with a steam input pipe, the preheater is connected with the filter mixer through a flange, the filter mixer is connected with the oxidizer, the oxidizer is connected with a condenser, and the condenser is connected with a formaldehyde output pipe. According to the utility model, a plurality of temperature, flow and pressure detectors are arranged, and each detector is interlocked with independent equipment and valves, so that the actual production condition of the production system is comprehensively monitored, the production system is ensured to always run under a controllable condition, once the reaction condition is exceeded, an input channel of raw materials can be cut off in time, and the production efficiency is improved. The safety of the production system is greatly improved, and the stable and reliable operation of the production system is ensured.

Description

Technical Field

[0001] This utility model relates to the field of formaldehyde production technology, specifically to a production system for safe formaldehyde production using the silver method. Background Technology

[0002] Formaldehyde is a versatile basic organic chemical raw material that can be used to produce various organic chemical products such as urea-formaldehyde, phenol-formaldehyde, butanediol, pentaerythritol, and paraformaldehyde. Currently, the silver catalyst method is the most widely used method in formaldehyde production. The silver catalyst method has a long history and has advantages such as mature technology, short process flow, low power consumption, low investment, and large single-series production capacity.

[0003] In the silver-process formaldehyde production process, methanol and oxygen react to produce formaldehyde, water, and hydrogen. The feed ratio must maintain an excess of methanol in the reaction. During the oxidation reaction, the oxygen content in the system must be kept below the explosive range of the methanol-oxygen mixture. If the oxygen content is too high, the oxidizer will overheat, or the explosion-proof membrane will rupture, causing a large leakage of methanol and formaldehyde gas from the oxidizer. A large amount of oxygen from the air will then enter the oxidizer, causing even more serious secondary disasters. Utility Model Content

[0004] To address the aforementioned problems, this utility model provides a safe formaldehyde production system using the silver method, which solves the problems that may occur in the prior art, such as excessively high oxygen content causing high temperature or explosion of the oxidizer, resulting in a large leakage of methanol and formaldehyde, or oxygen entering the oxidizer and causing secondary disasters.

[0005] To achieve the above objectives, this utility model provides a safe formaldehyde production system using the silver process, comprising a blower, a methanol storage tank, a methanol input pump, a methanol evaporator, a methanol reboiler, a steam distributor, a preheater, a filter mixer, and an oxidizer. The blower is connected to the preheater via a pipeline. The methanol storage tank, the methanol input pump, the methanol evaporator, and the methanol reboiler are sequentially connected via pipelines. The methanol reboiler is connected to the preheater. The steam distributor is connected to the jacket of the methanol evaporator and the preheater via pipelines. A steam input pipe is connected to the steam distributor. The preheater and the filter mixer are connected via flanges. The filter mixer is connected to the oxidizer. The oxidizer is connected to a condenser. The condenser is connected to a formaldehyde output pipe.

[0006] The methanol reboiler is equipped with a temperature detector, and a steam inlet valve is installed on the pipe between the steam distributor and the jacket of the methanol evaporator. The temperature detector is electrically connected to the steam inlet valve.

[0007] An air shut-off valve is installed on the pipeline between the fan and the preheater, and a second temperature detector is installed on the oxidizer. The second temperature detector is electrically connected to the air shut-off valve and the fan.

[0008] The filter mixer is equipped with an oxygen-to-ethanol ratio detector, which is electrically connected to the air shut-off valve and the fan.

[0009] Furthermore, an air filter is provided between the air shut-off valve and the preheater, and a methanol filter is provided between the methanol input pump and the methanol evaporator.

[0010] Furthermore, a nitrogen input pipe is connected to the filter mixer, and a nitrogen inlet valve is provided on the nitrogen input pipe.

[0011] Furthermore, the oxidizer is jacketed and connected to a steam drum, and the steam input pipe is connected to the steam drum.

[0012] Furthermore, the steam distributor is connected to two steam inlet branches, one of which is equipped with a second steam inlet valve, and both steam inlet branches are simultaneously connected to a first flow detector, which is connected to the preheater via a pipe.

[0013] Furthermore, a flow detector is installed between the methanol reboiler and the preheater.

[0014] Furthermore, a pressure detector and a flow detector are installed between the air filter and the preheater.

[0015] Furthermore, a pressure detector 2 is provided on the oxidizer.

[0016] The beneficial effects of this utility model are:

[0017] This utility model is equipped with multiple temperature, flow and pressure detectors, and interlocks each detector with some power supplies and valves to comprehensively monitor the production status of the production system, ensuring that the production system always operates under controllable conditions. Once the reaction conditions are exceeded, the input channel of the raw materials can be cut off in time, which greatly improves the safety of the production system and ensures the stable and reliable operation of the production system.

[0018] In this invention, a temperature detector is installed on the methanol reboiler. The temperature detector is interlocked with the steam inlet valve to effectively control the heating of the methanol evaporator by steam, thereby regulating the generation rate of methanol gas in the methanol evaporator, avoiding excessive methanol gas, and stopping the heating of the methanol evaporator in time when the temperature of the methanol reboiler is too high.

[0019] In this invention, a second temperature detector is installed on the oxidizer, and an oxygen-to-ethanol ratio detector is installed on the filter mixer. Both the second temperature detector and the oxygen-to-ethanol ratio detector are interlocked with the air shut-off valve and the fan power supply. The air intake speed of the fan is adjusted by the oxygen-to-ethanol ratio detector to prevent the reaction from getting out of control. If the oxidizer temperature exceeds the limit, the air input pipeline can be quickly shut off to prevent the continuous intake of air under the condition of temperature runaway, which could cause greater harm.

[0020] In this invention, the filter mixer is connected to a nitrogen input pipe. In the event of an accident, nitrogen can be introduced to protect the equipment and ensure its safety. Attached Figure Description

[0021] To more clearly illustrate the technical solution of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the production system structure;

[0023] Among them, 1-fan, 2-methanol storage tank, 3-methanol evaporator, 4-methanol reboiler, 5-steam distributor, 6-preheater, 7-filter mixer, 8-oxidizer, 9-methanol input pump, 10-steam input pipe, 11-condenser, 12-formaldehyde output pipe, 13-temperature detector one, 14-steam inlet valve one, 15-air shut-off valve, 16-temperature detector two, 17-oxygen-methanol ratio detector, 18-air filter, 19-methanol filter, 20-nitrogen input pipe, 21-nitrogen inlet valve, 22-steam drum, 23-steam inlet branch, 24-steam inlet valve two, 25-flow detector one, 26-flow detector two, 27-pressure detector one, 28-flow detector three, 29-pressure detector two. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0025] In one specific embodiment of this utility model, such as Figure 1As shown, a formaldehyde production system using the silver method includes a blower 1, a methanol storage tank 2, a methanol input pump 9, a methanol evaporator 3, a methanol reboiler 4, a steam distributor 5, a preheater 6, a filter mixer 7, and an oxidizer 8. The blower 1 is connected to the preheater 6 via a pipeline. The methanol storage tank 2, methanol input pump 9, methanol evaporator 3, and methanol reboiler 4 are connected sequentially via pipelines. The methanol reboiler 4 is connected to the preheater 6. The steam distributor 5 is connected to the jacket of the methanol evaporator 3 and the preheater 6 via pipelines. A steam input pipe 10 is connected to the steam distributor 5. The preheater 6 and the filter mixer 7 are connected via flanges. The filter mixer 7 is connected to the oxidizer 8. A steam drum 22 is connected to the jacket of the oxidizer 8. The steam input pipe 10 is connected to the steam drum 22. The oxidizer 8 is connected to a condenser 11. The condenser 11 is connected to a formaldehyde output pipe 12.

[0026] A temperature detector 13 is installed on the methanol reboiler 4, and a steam inlet valve 14 is installed on the pipe between the steam distributor 5 and the jacket of the methanol evaporator 3. The temperature detector 13 is electrically connected to the steam inlet valve 14.

[0027] An air shut-off valve 15 is installed on the pipe between the blower 1 and the preheater 6, and a temperature detector 2 16 is installed on the oxidizer 8. The temperature detector 2 16 is electrically connected to the air shut-off valve 15 and the blower 1.

[0028] The filter mixer 7 is equipped with an oxygen-to-ethanol ratio detector 17, which is electrically connected to the air shut-off valve 15 and the fan 1.

[0029] An air filter 18 is installed between the air shut-off valve 15 and the preheater 6, and a methanol filter 19 is installed between the methanol input pump 9 and the methanol evaporator 3.

[0030] A nitrogen inlet pipe 20 is connected to the filter mixer 7, and a nitrogen inlet valve 21 is installed on the nitrogen inlet pipe 20.

[0031] The steam distributor 5 is connected to two steam inlet branches 23. One of the steam inlet branches 23 is equipped with a second steam inlet valve 24. Both steam inlet branches 23 are connected to a first flow detector 25. The first flow detector 25 is connected to the preheater 6 through a pipe.

[0032] A flow detector 26 is installed between the methanol reboiler 4 and the preheater 6. A pressure detector 27 and a flow detector 3 28 are installed between the air filter 18 and the preheater 6. A pressure detector 29 is installed on the oxidizer 8.

[0033] The process of using this utility model:

[0034] Air is introduced into the preheater 6 through the air filter 18 by the blower 1. Methanol is introduced into the preheater 6 through the methanol storage tank 2 through the methanol filter 19, methanol evaporator 3, and methanol reboiler 4. Soft water is contained in the steam drum 22. The soft water is heated by the jacket of the oxidizer 8 to produce saturated steam at about 0.35 MPa. The steam is sent to the jacket of the methanol evaporator 3 through the steam distributor 5 to heat the methanol evaporator 3, and to the preheater 6. In the preheater 6, a ternary mixture of methanol, air, and steam is formed. After being heated by the preheater 6 and filtered by the filter mixer 7 to remove impurities, the ternary mixture enters the oxidizer 8 for a high-temperature reaction. The oxidizer 8 is equipped with a silver catalyst. The ternary mixture reacts with the silver catalyst at 20~30 kPa and 620~650℃ to convert methanol into formaldehyde gas. After being cooled by the condenser 11, the formaldehyde is sent to the subsequent absorption tower for formaldehyde collection through the formaldehyde output pipe 12.

[0035] A temperature detector 13 is installed on the methanol reboiler 4. A steam inlet valve 14 is installed on the pipe between the steam distributor 5 and the jacket of the methanol evaporator 3. The temperature detector 13 is electrically connected to the steam inlet valve 14. Once the temperature exceeds the set value, the steam inlet valve 14 is automatically shut off, thereby stopping the heating of the methanol evaporator 3, stopping the methanol evaporation and the feeding process into the methanol reboiler 4.

[0036] An air shut-off valve 15 is installed on the pipeline between the blower 1 and the preheater 6. A temperature detector 16 is installed in the oxidizer 8. The temperature detector 16 is electrically connected to the air shut-off valve 15 and the blower 1. The temperature detector 16 is connected to four temperature measuring points in the oxidizer 8. If any two temperature measuring points exceed the set value, the air shut-off valve 15 will be automatically shut off and the blower 1 will stop running.

[0037] The filter mixer 7 is equipped with an oxygen-to-ethanol ratio detector 17, which is electrically connected to the air shut-off valve 15 and the fan 1. By detecting the oxygen-to-ethanol ratio in the filter mixer 7, if the oxygen-to-ethanol ratio is not within the set range, the air shut-off valve 26 will be automatically shut off and the fan 1 will be stopped.

[0038] The steam distributor 5 is connected to two steam inlet branches 23. One of the steam inlet branches 23 is equipped with a second steam inlet valve 24. Both steam inlet branches 23 are connected to a first flow detector 25. The first flow detector 25 is connected to the preheater 6 through a pipe. The first flow detector 25 is used to detect the amount of steam input into the preheater 6. If the amount of steam input is lower than the set value, steam compensation can be performed by opening the second steam inlet valve 24.

[0039] Pressure detector 27 and flow detector 28 are installed on the pipeline between fan 1 and preheater 6. When the pressure and flow of fan 1 are out of range, an alarm will be triggered and the air shut-off valve 15 will be shut off in time for emergency shutdown.

[0040] After the production system is shut down in an emergency, nitrogen is introduced into the production unit through the nitrogen inlet pipe 20 to protect the production unit and prevent accidents such as overheating and explosion.

[0041] Unless otherwise specified or further limited to one preferred or alternative technical means being another, the preferred and alternative technical means disclosed in this utility model can be arbitrarily combined to form several different technical solutions. Therefore, equivalent changes made according to the claims are still within the scope of this utility model.

Claims

1. A production system for the safe production of formaldehyde using the silver method, characterized in that, The system includes a blower (1), a methanol storage tank (2), a methanol input pump (9), a methanol evaporator (3), a methanol reboiler (4), a steam distributor (5), a preheater (6), a filter mixer (7), and an oxidizer (8). The blower (1) is connected to the preheater (6) via a pipe. The methanol storage tank (2), the methanol input pump (9), the methanol evaporator (3), and the methanol reboiler (4) are connected in sequence via pipes. The methanol reboiler (4) is connected to the preheater (6). The steam distributor (5) is connected to the jacket of the methanol evaporator (3) and the preheater (6) via pipes. A steam input pipe (10) is connected to the steam distributor (5). The preheater (6) and the filter mixer (7) are connected via flanges. The filter mixer (7) is connected to the oxidizer (8). The oxidizer (8) is connected to a condenser (11). The condenser (11) is connected to a formaldehyde output pipe (12). A temperature detector (13) is installed on the methanol reboiler (4), and a steam inlet valve (14) is installed on the pipe between the steam distributor (5) and the jacket of the methanol evaporator (3). The temperature detector (13) is electrically connected to the steam inlet valve (14). An air shut-off valve (15) is installed on the pipe between the blower (1) and the preheater (6), and a temperature detector (2) (16) is installed on the oxidizer (8). The temperature detector (2) (16) is electrically connected to the air shut-off valve (15) and the blower (1). The filter mixer (7) is equipped with an oxygen-to-ethanol ratio detector (17), which is electrically connected to the air shut-off valve (15) and the fan (1).

2. The silver-based safe formaldehyde production system according to claim 1, characterized in that, An air filter (18) is provided between the air shut-off valve (15) and the preheater (6), and a methanol filter (19) is provided between the methanol input pump (9) and the methanol evaporator (3).

3. The silver-based safe formaldehyde production system according to claim 1, characterized in that, The filter mixer (7) is connected to a nitrogen input pipe (20), and a nitrogen inlet valve (21) is provided on the nitrogen input pipe (20).

4. The silver-based safe formaldehyde production system according to claim 1, characterized in that, The oxidizer (8) is jacketed with a steam drum (22), and the steam input pipe (10) is connected to the steam drum (22).

5. The silver-based safe formaldehyde production system according to claim 1, characterized in that, The steam distributor (5) is connected to two steam inlet branches (23), one of which is equipped with a second steam inlet valve (24). Both steam inlet branches (23) are connected to a first flow detector (25), which is connected to the preheater (6) through a pipe.

6. The silver-based safe formaldehyde production system according to claim 1, characterized in that, A flow detector 26 is provided between the methanol reboiler (4) and the preheater (6).

7. The silver-based safe formaldehyde production system according to claim 2, characterized in that, Pressure detector 1 (27) and flow detector 3 (28) are provided between the air filter (18) and the preheater (6).

8. The silver-based safe formaldehyde production system according to claim 1, characterized in that, The oxidizer (8) is equipped with a pressure detector 2 (29).

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