A high-concentration formaldehyde solution production control method and system

Abstract

The application discloses a high-concentration formaldehyde solution production control method and system, relates to the technical field of formaldehyde solution production, and comprises the following steps: S1, installing a deionized water supply tank at one end of a deionized water inlet pipe of an absorption tower, and winding and installing steam heating pipes on the surface of the deionized water supply tank to heat the deionized water in the deionized water supply tank; in the scheme, the steam heating pipes are wound on the deionized water supply tank to heat the deionized water in the deionized water supply tank, the steam in the steam heating pipes is heated by high-temperature formaldehyde gas after distillation and purification, on one hand, the deionized water can be preheated to fully utilize the residual temperature of the high-temperature formaldehyde steam, and the method is more environmentally friendly and energy-saving, and on the other hand, the high-temperature formaldehyde gas in the steam heating pipes can be sent into a quenching tower again, so that the working pressure in the quenching tower can be reduced.

Description

Technical Field

[0001] This invention relates to the field of formaldehyde solution production technology, specifically to a method and system for controlling the production of high-concentration formaldehyde solution. Background Technology

[0002] High-concentration formaldehyde solution typically refers to an aqueous solution of formaldehyde with a concentration ≥37% (commonly known as formalin stock solution). It is a colorless, transparent liquid with a strong, pungent odor and high volatility. Its chemical properties are reactive, and it readily polymerizes to form paraformaldehyde, requiring the addition of stabilizers (such as methanol) to inhibit self-polymerization. This solution is widely used in disinfection and preservation, phenolic resin synthesis, pharmaceuticals, and the textile industry. The production process of high-concentration formaldehyde solution requires the following steps: heating of methanol raw material, methanol evaporation, oxidation reaction, quench absorption, and distillation purification. During the quench absorption process, the high-temperature formaldehyde gas (600℃) after the reaction is sent to a quench tower to cool down to 80℃~100℃. Then, the cooled gas is sent to an absorption tower to be absorbed and mixed with deionized water in a countercurrent manner to form a formaldehyde solution.

[0003] Formaldehyde gas is cooled in a quench tower and then absorbed in an absorption tower. The gas phase temperature of formaldehyde gas in the absorption tower should be controlled between 80℃ and 100℃, and the liquid phase temperature of deionized water in the absorption tower should be controlled between 60℃ and 80℃. However, if the reaction temperature is lower than 60℃ during the formation of formaldehyde solution in the absorption tower, the polymerization rate of formaldehyde will be significantly accelerated, forming white solid paraformaldehyde. The formation of paraformaldehyde not only affects the production volume of high-concentration formaldehyde solution, but its solid form can also cause blockage of the absorption tower and pipes, seriously affecting the production efficiency and cost of high-concentration formaldehyde solution. Therefore, we propose a method and system for controlling the production of high-concentration formaldehyde solution. Summary of the Invention

[0004] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a method and system for controlling the production of high-concentration formaldehyde solution, thereby solving the aforementioned problems in the prior art.

[0005] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: a method for controlling the production of high-concentration formaldehyde solution, comprising the following steps: S1: Install a deionized water supply tank at one end of the deionized water inlet pipe of the absorption tower. Wrap a steam heating pipe around the surface of the deionized water supply tank to heat the deionized water in the tank. Both ends of the steam heating pipe are fixedly connected to the high-temperature gas inlet pipe of the quench tower. One-way control valves are installed at both ends of the steam heating pipe. A temperature sensor is installed on the deionized water supply tank to continuously monitor the deionized water temperature. S2: Obtain the liquid phase temperature in the absorption tower, set the liquid phase temperature tolerance range, and determine whether the deionized water in the supply water tank needs to be preheated by the liquid phase temperature and the liquid phase temperature tolerance range. When the deionized water needs to be preheated, adjust the control valve of the steam heating pipe by the current liquid phase temperature in the absorption tower and the current deionized water temperature in the supply water tank. S3: Obtain the gas phase temperature inside the absorption tower, set the gas phase temperature tolerance range, and determine whether it is necessary to adjust the spray water volume per unit time of the quench tower based on the gas phase temperature and the gas phase temperature tolerance range. When it is necessary to adjust the spray water volume per unit time of the quench tower, adjust the spray water pipe control valve of the quench tower based on the current gas phase temperature inside the absorption tower and the current spray water volume per unit time of the quench tower.

[0006] Preferably, in S1, a temperature sensor is installed on the deionized water supply tank to continuously monitor the deionized water temperature, specifically: S101: Obtain the liquid level in the deionized water supply tank, obtain the water temperature at the highest point of the deionized water in the supply tank, and obtain the water temperature at the lowest point of the deionized water in the supply tank. S102: The average of the lowest and highest temperatures of the deionized water in the supply tank is used to obtain the current ionized water temperature. The measurement time interval is set, and multiple current ionized water temperatures are measured according to the measurement time interval. An ionized water temperature observation database is established, and all current ionized water temperatures are arranged in chronological order and stored in the ionized water temperature observation database.

[0007] Preferably, in step S2, the determination of whether preheating of the deionized water in the supply tank is necessary is based on the liquid phase temperature and the liquid phase temperature tolerance range. Specifically: S201: Obtain the liquid phase temperature in the absorption tower, obtain the liquid phase temperature tolerance range, and determine whether the liquid phase temperature in the absorption tower is within the liquid phase temperature tolerance range. If the liquid phase temperature in the absorption tower is within the liquid phase temperature tolerance range, set a judgment interval period and repeat the judgment according to the judgment interval period. If the liquid phase temperature in the absorption tower is not within the liquid phase temperature tolerance range, execute S202. S202: Obtain the minimum value of the liquid phase temperature tolerance range, and determine whether the liquid phase temperature in the absorption tower is less than or equal to the minimum value of the liquid phase temperature tolerance range. If the liquid phase temperature in the absorption tower is less than or equal to the minimum value of the liquid phase temperature tolerance range, the result is that the deionized water in the supply water tank needs to be preheated. If the liquid phase temperature in the absorption tower is greater than the minimum value of the liquid phase temperature tolerance range, then execute S203. S203: Obtain the highest value of the liquid phase temperature tolerance range and determine whether the liquid phase temperature in the absorption tower is greater than or equal to the highest value of the liquid phase temperature tolerance range. If the liquid phase temperature in the absorption tower is greater than or equal to the highest value of the liquid phase temperature tolerance range, an alarm will be activated to notify the management personnel to cool down the deionized water in the supply water tank. If the liquid phase temperature in the absorption tower is less than the highest value of the liquid phase temperature tolerance range, an alarm will be activated to notify the management personnel that the liquid phase temperature in the absorption tower is malfunctioning and needs to be repaired in time.

[0008] Preferably, in S2, when preheating of deionized water is required, the control valve of the steam heating pipe is adjusted by the current liquid phase temperature in the absorption tower and the current deionized water temperature in the supply water tank, specifically as follows: S204: Obtain the current liquid phase temperature in the absorption tower, obtain the minimum and maximum values ​​of the liquid phase temperature tolerance range, sum the minimum and maximum values ​​of the liquid phase temperature tolerance range and take the average value to obtain the target temperature, and obtain the temperature difference to be raised by subtracting the target temperature from the current liquid phase temperature in the absorption tower. S205: Obtain the current deionized water temperature in the supply water tank, and sum the difference between the current deionized water temperature in the supply water tank and the temperature to be raised to obtain the preheating temperature; S206: Open the control valve of the steam heating tube until the temperature of the deionized water in the supply water tank reaches the preheating temperature, then close the control valve of the steam heating tube.

[0009] Preferably, in S3, the determination of whether it is necessary to adjust the spray water volume per unit time of the quench tower is based on the gas phase temperature and the gas phase temperature tolerance range, specifically: S301: Obtain the gas phase temperature inside the absorption tower, obtain the gas phase temperature tolerance range, determine whether the gas phase temperature inside the absorption tower is within the gas phase temperature tolerance range, if the gas phase temperature inside the absorption tower is within the gas phase temperature tolerance range, then set a judgment time period, and repeat the judgment according to the judgment time period; if the gas phase temperature inside the absorption tower is within the gas phase temperature tolerance range, then execute S302. S302: Obtain the minimum value of the gas phase temperature tolerance range, determine whether the gas phase temperature in the absorption tower is less than or equal to the minimum value of the gas phase temperature tolerance range, if the gas phase temperature in the absorption tower is less than or equal to the minimum value of the gas phase temperature tolerance range, the result is that the spray water volume per unit time of the quench tower needs to be adjusted and the spray water volume per unit time needs to be reduced, if the gas phase temperature in the absorption tower is greater than the minimum value of the gas phase temperature tolerance range, then execute S303. S303: Obtain the highest value of the gas phase temperature tolerance range and determine whether the gas phase temperature in the absorption tower is greater than the highest value of the gas phase temperature tolerance range. If the gas phase temperature in the absorption tower is greater than the highest value of the gas phase temperature tolerance range, the result is that the spray water volume per unit time of the quench tower needs to be adjusted and the spray water volume per unit time needs to be increased. If the gas phase temperature in the absorption tower is less than or equal to the highest value of the gas phase temperature tolerance range, an alarm is activated to notify the management personnel that the gas phase temperature in the absorption tower has been reported as an error and timely maintenance is required.

[0010] Preferably, S301 further includes: S3011: Obtain the adjustment status of the control valve of the steam heating tube and determine whether the adjustment status of the control valve of the steam heating tube has changed; S3012: If the control valve adjustment state of the steam heating pipe changes, immediately execute 301 to determine whether the gas phase temperature in the absorption tower is within the gas phase temperature tolerance range.

[0011] Preferably, in S3, when it is necessary to adjust the spray water volume per unit time in the quench tower, the spray water pipe control valve of the quench tower is adjusted by the current gas phase temperature in the absorption tower and the current spray water volume per unit time in the quench tower, specifically as follows: S304: The opening degree of the quench tower spray water pipe control valve is divided into six different opening degree values ​​from 0 to 5. The current opening degree of the quench tower spray water pipe control valve is obtained, and the judgment result of whether the spray water volume per unit time needs to be increased or decreased is obtained. If the judgment result of the adjustment of the spray water volume per unit time is to increase, the control valve is adjusted to move one opening degree in the direction of increasing the flow rate of the quench tower spray water pipe. If the judgment result of the adjustment of the spray water volume per unit time is to decrease, the control valve is adjusted to move one opening degree in the direction of decreasing the flow rate of the quench tower spray water pipe. S305: Determine whether the opening degree of the control valve for the spray water pipe of the quench tower has changed. If the opening degree of the control valve for the spray water pipe of the quench tower has changed, repeat S301.

[0012] A high-concentration formaldehyde solution production control system includes the following modules: The deionized water temperature monitoring module has a deionized water supply tank installed at one end of the deionized water inlet pipe of the absorption tower. A steam heating pipe is wound and installed on the surface of the deionized water supply tank to heat the deionized water in the tank. Both ends of the steam heating pipe are fixedly connected to the high-temperature gas inlet pipe of the quench tower. A one-way control valve is installed at both ends of the steam heating pipe. A temperature sensor is installed on the deionized water supply tank to continuously monitor the deionized water temperature. The liquid phase temperature control module acquires the liquid phase temperature in the absorption tower, sets the liquid phase temperature tolerance range, and determines whether the deionized water in the supply water tank needs to be preheated based on the liquid phase temperature and the liquid phase temperature tolerance range. When preheating of deionized water is required, the control valve of the steam heating pipe is adjusted based on the current liquid phase temperature in the absorption tower and the current deionized water temperature in the supply water tank. The gas phase temperature control module acquires the gas phase temperature inside the absorption tower, sets the gas phase temperature tolerance range, and determines whether it is necessary to adjust the spray water volume per unit time of the quench tower based on the gas phase temperature and the gas phase temperature tolerance range. When it is necessary to adjust the spray water volume per unit time of the quench tower, the spray water pipe control valve of the quench tower is adjusted based on the current gas phase temperature inside the absorption tower and the current spray water volume per unit time of the quench tower.

[0013] (III) Beneficial Effects This invention provides a method and system for controlling the production of high-concentration formaldehyde solution, which has the following beneficial effects: (1) In this scheme, the deionized water in the deionized water supply tank is heated by wrapping a steam heating pipe around the deionized water supply tank. The steam in the steam heating pipe is heated by the high-temperature formaldehyde gas after distillation and purification. Since the temperature of the high-temperature formaldehyde gas after distillation and purification is about 600℃, the 600℃ high-temperature formaldehyde gas needs to be sent to the cooling tower to cool down during the production process. Therefore, sending some of the uncooled high-temperature formaldehyde gas to the steam heating pipe can preheat the deionized water and make full use of the remaining temperature of the high-temperature formaldehyde steam, which is more environmentally friendly and energy-saving. On the other hand, the high-temperature formaldehyde gas in the steam heating pipe is then sent into the quench tower, which can reduce the working pressure in the quench tower.

[0014] (2) In this scheme, by setting six different opening values ​​of 0-5 on the control valve of the spray water pipe of the quench tower, adjusting the opening level by level and then detecting the temperature to further adjust the opening, it is beneficial to avoid the situation where the formaldehyde gas temperature drops or rises sharply due to a large change in the flow rate of the spray water pipe of the quench tower. This facilitates the stabilization of the formaldehyde gas temperature fluctuation from the quench tower to the absorption tower, thereby avoiding a large impact on the absorption reaction temperature in the absorption tower. This makes the production environment safer while avoiding the generation of paraformaldehyde. Attached Figure Description

[0015] Figure 1 This is a schematic diagram illustrating the structure of a high-concentration formaldehyde solution production control system according to the present invention. Figure 2 This is a flowchart of a high-concentration formaldehyde solution production control method according to the present invention; Figure 3 This is a schematic diagram of the module structure of a high-concentration formaldehyde solution production control system according to the present invention.

[0016] In the diagram: 1. Deionized water supply tank; 2. Steam heating pipe; 3. Formaldehyde high-temperature gas inlet pipe; 4. Quenching tower; 5. Quenching tower spray water pipe control valve; 6. Absorption tower; 7. Steam heating pipe one-way control valve. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Please see Figures 1-2 This invention provides a method for controlling the production of high-concentration formaldehyde solution, comprising the following steps: S1: Install a deionized water supply tank at one end of the deionized water inlet pipe of the absorption tower. Wrap a steam heating pipe around the surface of the deionized water supply tank to heat the deionized water in the tank. Both ends of the steam heating pipe are fixedly connected to the high-temperature gas inlet pipe of the quench tower. One-way control valves are installed at both ends of the steam heating pipe. A temperature sensor is installed on the deionized water supply tank to continuously monitor the deionized water temperature. S2: Obtain the liquid phase temperature in the absorption tower, set the liquid phase temperature tolerance range, and determine whether the deionized water in the supply water tank needs to be preheated by the liquid phase temperature and the liquid phase temperature tolerance range. When the deionized water needs to be preheated, adjust the control valve of the steam heating pipe by the current liquid phase temperature in the absorption tower and the current deionized water temperature in the supply water tank. S3: Obtain the gas phase temperature inside the absorption tower, set the gas phase temperature tolerance range, and determine whether it is necessary to adjust the spray water volume per unit time of the quench tower based on the gas phase temperature and the gas phase temperature tolerance range. When it is necessary to adjust the spray water volume per unit time of the quench tower, adjust the spray water pipe control valve of the quench tower based on the current gas phase temperature inside the absorption tower and the current spray water volume per unit time of the quench tower.

[0019] In this embodiment, the deionized water in the deionized water supply tank is heated by winding a steam heating pipe around the tank. The steam in the heating pipe is heated by distilled and purified formaldehyde high-temperature gas. Since the temperature of the distilled and purified formaldehyde high-temperature gas is around 600°C, it needs to be sent to a cooling tower to cool down during the production process. Therefore, sending some of the uncooled formaldehyde high-temperature gas to the steam heating pipe can preheat the deionized water and make full use of the remaining temperature of the formaldehyde high-temperature steam, which is more environmentally friendly and energy-saving. On the other hand, sending the formaldehyde high-temperature gas in the steam heating pipe into the quench tower can reduce the working pressure in the quench tower. The one-way control valves installed at both ends of the steam heating pipe can control the amount of formaldehyde high-temperature gas entering, thereby controlling the preheating temperature of the deionized water. They can also facilitate the flow of formaldehyde high-temperature gas in the steam heating pipe and avoid backflow. In this scheme, the liquid phase temperature is monitored by a temperature sensor inside the absorption tower. Then, it is determined whether the liquid phase temperature needs to be adjusted based on the liquid phase temperature and the liquid phase temperature tolerance range. The liquid phase temperature tolerance range is generally controlled between 60℃ and 80℃. Based on the judgment result, the control valve of the steam heating pipe is adjusted to preheat the deionized water. This allows the preheated deionized water to enter the absorption tower and neutralize the liquid phase temperature, bringing it within the liquid phase temperature tolerance range. This avoids the deionized water from being too cold in the absorption tower, which would cause paraformaldehyde precipitation and blockage of the tower and pipes. The liquid phase temperature here is the temperature of the deionized water mixture sprayed from top to bottom onto the packing material of the absorption tower. In this scheme, the gas phase temperature is monitored by a temperature sensor inside the absorption tower. Then, based on the gas phase temperature and its tolerance range, it is determined whether the gas phase temperature needs to be adjusted. The tolerance range is generally controlled between 80℃ and 100℃. Based on the judgment result, the spray water volume of the quench tower is adjusted per unit time, thereby regulating the temperature of the formaldehyde gas entering the absorption tower. This avoids the formation of polyformaldehyde precipitation due to excessively low temperature of the formaldehyde gas inside the absorption tower, which can cause tower and pipe blockage. The gas phase temperature here refers to the temperature of the formaldehyde gas mixture blown upwards onto the packing material of the absorption tower.

[0020] In S1, a temperature sensor is installed on the ionized water supply tank to continuously monitor the deionized water temperature, specifically: S101: Obtain the liquid level in the deionized water supply tank, obtain the water temperature at the highest point of the deionized water in the supply tank, and obtain the water temperature at the lowest point of the deionized water in the supply tank. S102: The average of the lowest and highest temperatures of the deionized water in the supply tank is used to obtain the current ionized water temperature. The measurement time interval is set, and multiple current ionized water temperatures are measured according to the measurement time interval. An ionized water temperature observation database is established, and all current ionized water temperatures are arranged in chronological order and stored in the ionized water temperature observation database.

[0021] In this embodiment, by continuously monitoring and recording the temperature of the deionized water, it is convenient to heat the deionized water as soon as it cools down, thereby avoiding the natural loss of temperature of the deionized water and causing the temperature of the deionized water entering the absorption tower to drop below 60 degrees Celsius. This helps to prevent methanol gas in the absorption tower from being absorbed by the low-temperature deionized water to generate paraformaldehyde and cause tower blockage.

[0022] In S2, the need to preheat the deionized water in the supply tank is determined by the liquid phase temperature and its tolerance range. Specifically: S201: Obtain the liquid phase temperature in the absorption tower, obtain the liquid phase temperature tolerance range, and determine whether the liquid phase temperature in the absorption tower is within the liquid phase temperature tolerance range. If the liquid phase temperature in the absorption tower is within the liquid phase temperature tolerance range, set a judgment interval period and repeat the judgment according to the judgment interval period. If the liquid phase temperature in the absorption tower is not within the liquid phase temperature tolerance range, execute S202. S202: Obtain the minimum value of the liquid phase temperature tolerance range, and determine whether the liquid phase temperature in the absorption tower is less than or equal to the minimum value of the liquid phase temperature tolerance range. If the liquid phase temperature in the absorption tower is less than or equal to the minimum value of the liquid phase temperature tolerance range, the result is that the deionized water in the supply water tank needs to be preheated. If the liquid phase temperature in the absorption tower is greater than the minimum value of the liquid phase temperature tolerance range, then execute S203. S203: Obtain the highest value of the liquid phase temperature tolerance range, determine whether the liquid phase temperature in the absorption tower is greater than or equal to the highest value of the liquid phase temperature tolerance range, if the liquid phase temperature in the absorption tower is greater than or equal to the highest value of the liquid phase temperature tolerance range, then activate the alarm to notify the management personnel to cool down the deionized water in the supply water tank; if the liquid phase temperature in the absorption tower is less than the highest value of the liquid phase temperature tolerance range, then activate the alarm to notify the management personnel that the liquid phase temperature in the absorption tower is malfunctioning and needs to be repaired in time. S204: Obtain the current liquid phase temperature in the absorption tower, obtain the minimum and maximum values ​​of the liquid phase temperature tolerance range, sum the minimum and maximum values ​​of the liquid phase temperature tolerance range and take the average value to obtain the target temperature, and obtain the temperature difference to be raised by subtracting the target temperature from the current liquid phase temperature in the absorption tower. S205: Obtain the current deionized water temperature in the supply water tank, and sum the difference between the current deionized water temperature in the supply water tank and the temperature to be raised to obtain the preheating temperature; S206: Open the control valve of the steam heating tube until the temperature of the deionized water in the supply water tank reaches the preheating temperature, then close the control valve of the steam heating tube.

[0023] In this embodiment, it is first determined whether the liquid phase temperature is within the liquid phase temperature tolerance range, and then it is further determined whether the liquid phase temperature is too low or too high. This facilitates heating the deionized water in the supply water tank to increase the temperature of the deionized water in the absorption tower when the liquid phase temperature is too low. Under normal circumstances, the temperature of the deionized water in the supply water tank will not be too high. If the temperature of the deionized water in the supply water tank is too high, the operator only needs to add low-temperature deionized water to the supply water tank to neutralize the water temperature. When a temperature error is detected or the water temperature in the supply water tank is too high, an alarm is activated to notify the operator, which facilitates the operator to troubleshoot the fault. This facilitates the intelligent production of high-concentration formaldehyde solution and avoids serious losses in formaldehyde solution production caused by temperature sensor failure.

[0024] In S3, the need to adjust the spray water volume per unit time of the quench tower is determined by the gas phase temperature and its tolerance range. Specifically: S301: Obtain the gas phase temperature inside the absorption tower, obtain the gas phase temperature tolerance range, determine whether the gas phase temperature inside the absorption tower is within the gas phase temperature tolerance range, if the gas phase temperature inside the absorption tower is within the gas phase temperature tolerance range, then set a judgment time period, and repeat the judgment according to the judgment time period; if the gas phase temperature inside the absorption tower is within the gas phase temperature tolerance range, then execute S302. S3011: Obtain the adjustment status of the control valve of the steam heating tube and determine whether the adjustment status of the control valve of the steam heating tube has changed; S3012: If the control valve adjustment state of the steam heating pipe changes, immediately execute 301 to determine whether the gas phase temperature in the absorption tower is within the gas phase temperature tolerance range. S302: Obtain the minimum value of the gas phase temperature tolerance range, determine whether the gas phase temperature in the absorption tower is less than or equal to the minimum value of the gas phase temperature tolerance range, if the gas phase temperature in the absorption tower is less than or equal to the minimum value of the gas phase temperature tolerance range, the result is that the spray water volume per unit time of the quench tower needs to be adjusted and the spray water volume per unit time needs to be reduced, if the gas phase temperature in the absorption tower is greater than the minimum value of the gas phase temperature tolerance range, then execute S303. S303: Obtain the maximum value of the gas phase temperature tolerance range, determine whether the gas phase temperature in the absorption tower is greater than the maximum value of the gas phase temperature tolerance range, if the gas phase temperature in the absorption tower is greater than the maximum value of the gas phase temperature tolerance range, the result is that the spray water volume per unit time of the quench tower needs to be adjusted and the spray water volume per unit time needs to be increased; if the gas phase temperature in the absorption tower is less than or equal to the maximum value of the gas phase temperature tolerance range, then the alarm is activated to notify the management personnel that the gas phase temperature in the absorption tower is reported as an error and needs to be repaired in time. S304: The opening degree of the quench tower spray water pipe control valve is divided into six different opening degree values ​​from 0 to 5. The current opening degree of the quench tower spray water pipe control valve is obtained, and the judgment result of whether the spray water volume per unit time needs to be increased or decreased is obtained. If the judgment result of the adjustment of the spray water volume per unit time is to increase, the control valve is adjusted to move one opening degree in the direction of increasing the flow rate of the quench tower spray water pipe. If the judgment result of the adjustment of the spray water volume per unit time is to decrease, the control valve is adjusted to move one opening degree in the direction of decreasing the flow rate of the quench tower spray water pipe. S305: Determine whether the opening degree of the control valve for the spray water pipe of the quench tower has changed. If the opening degree of the control valve for the spray water pipe of the quench tower has changed, repeat S301.

[0025] In this embodiment, the first step is to determine whether the gas phase temperature is within the tolerable range. Then, it is further determined whether the gas phase temperature is too high or too low. This allows for targeted adjustment of the opening direction of the control valve on the quench tower spray water pipe. Since the normal temperature of the formaldehyde gas entering the absorption tower is between 80℃ and 100℃, and the temperature range for the formation of paraformaldehyde is large below 60℃, the gas phase temperature will not normally be lower than 60℃. However, because some of the high-temperature formaldehyde gas is used to heat the supply water tank, the temperature of the high-temperature formaldehyde gas flowing into the quench tower will fluctuate. If the flow rate of the quench tower spray water pipe remains constant at this time, the temperature of the formaldehyde gas flowing from the quench tower into the absorption tower will fluctuate. Therefore, when the control valve of the steam heating pipe changes its adjustment state, the monitoring of the gas phase temperature is quickly activated to prevent the gas phase temperature in the absorption tower from falling below 60℃ and generating paraformaldehyde. In this solution, six different opening values ​​(0-5) are set on the control valve of the quench tower spray water pipe, and the opening is adjusted step by step by detecting the temperature and further adjusting the opening. This helps to avoid the situation where the formaldehyde gas temperature drops or rises sharply due to a large change in the flow rate of the quench tower spray water pipe. This facilitates the stabilization of the formaldehyde gas temperature fluctuation from the quench tower into the absorption tower, thereby avoiding a significant impact on the absorption reaction temperature in the absorption tower. This makes the production environment safer while preventing the generation of paraformaldehyde.

[0026] Please see Figures 1-2 This invention provides a high-concentration formaldehyde solution production control system, comprising the following modules: The deionized water temperature monitoring module has a deionized water supply tank installed at one end of the deionized water inlet pipe of the absorption tower. A steam heating pipe is wound and installed on the surface of the deionized water supply tank to heat the deionized water in the tank. Both ends of the steam heating pipe are fixedly connected to the high-temperature gas inlet pipe of the quench tower. A one-way control valve is installed at both ends of the steam heating pipe. A temperature sensor is installed on the deionized water supply tank to continuously monitor the deionized water temperature. The liquid phase temperature control module acquires the liquid phase temperature in the absorption tower, sets the liquid phase temperature tolerance range, and determines whether the deionized water in the supply water tank needs to be preheated based on the liquid phase temperature and the liquid phase temperature tolerance range. When preheating of deionized water is required, the control valve of the steam heating pipe is adjusted based on the current liquid phase temperature in the absorption tower and the current deionized water temperature in the supply water tank. The gas phase temperature control module acquires the gas phase temperature inside the absorption tower, sets the gas phase temperature tolerance range, and determines whether it is necessary to adjust the spray water volume per unit time of the quench tower based on the gas phase temperature and the gas phase temperature tolerance range. When it is necessary to adjust the spray water volume per unit time of the quench tower, the spray water pipe control valve of the quench tower is adjusted based on the current gas phase temperature inside the absorption tower and the current spray water volume per unit time of the quench tower.

[0027] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented in software, the above embodiments can be implemented, in whole or in part, as a computer program product. Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution.

[0028] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0029] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A method for controlling the production of high-concentration formaldehyde solution, characterized in that, Includes the following steps: S1: Install a deionized water supply tank at one end of the deionized water inlet pipe of the absorption tower. Wrap a steam heating pipe around the surface of the deionized water supply tank to heat the deionized water in the tank. Both ends of the steam heating pipe are fixedly connected to the high-temperature gas inlet pipe of the quench tower. One-way control valves are installed at both ends of the steam heating pipe. A temperature sensor is installed on the deionized water supply tank to continuously monitor the deionized water temperature. S2: Obtain the liquid phase temperature in the absorption tower, set the liquid phase temperature tolerance range, and determine whether the deionized water in the supply water tank needs to be preheated by the liquid phase temperature and the liquid phase temperature tolerance range. When the deionized water needs to be preheated, adjust the control valve of the steam heating pipe by the current liquid phase temperature in the absorption tower and the current deionized water temperature in the supply water tank. S3: Obtain the gas phase temperature in the absorption tower, set the gas phase temperature tolerance range, and determine whether it is necessary to adjust the spray water volume per unit time of the quench tower based on the gas phase temperature and the gas phase temperature tolerance range. When it is necessary to adjust the spray water volume per unit time of the quench tower, adjust the spray water pipe control valve of the quench tower based on the current gas phase temperature in the absorption tower and the current spray water volume per unit time of the quench tower. In S3, the need to adjust the spray water volume per unit time of the quench tower is determined by the gas phase temperature and its tolerance range. Specifically: S301: Obtain the gas phase temperature inside the absorption tower, obtain the gas phase temperature tolerance range, determine whether the gas phase temperature inside the absorption tower is within the gas phase temperature tolerance range, if the gas phase temperature inside the absorption tower is within the gas phase temperature tolerance range, then set a judgment time period, and repeat the judgment according to the judgment time period; if the gas phase temperature inside the absorption tower is within the gas phase temperature tolerance range, then execute S302. S302: Obtain the minimum value of the gas phase temperature tolerance range, determine whether the gas phase temperature in the absorption tower is less than or equal to the minimum value of the gas phase temperature tolerance range, if the gas phase temperature in the absorption tower is less than or equal to the minimum value of the gas phase temperature tolerance range, the result is that the spray water volume per unit time of the quench tower needs to be adjusted and the spray water volume per unit time needs to be reduced, if the gas phase temperature in the absorption tower is greater than the minimum value of the gas phase temperature tolerance range, then execute S303. S303: Obtain the maximum value of the gas phase temperature tolerance range, determine whether the gas phase temperature in the absorption tower is greater than the maximum value of the gas phase temperature tolerance range, if the gas phase temperature in the absorption tower is greater than the maximum value of the gas phase temperature tolerance range, the result is that the spray water volume per unit time of the quench tower needs to be adjusted and the spray water volume per unit time needs to be increased; if the gas phase temperature in the absorption tower is less than or equal to the maximum value of the gas phase temperature tolerance range, then the alarm is activated to notify the management personnel that the gas phase temperature in the absorption tower is reported as an error and needs to be repaired in time. S301 also includes: S3011: Obtain the adjustment status of the control valve of the steam heating tube and determine whether the adjustment status of the control valve of the steam heating tube has changed; S3012: If the control valve adjustment state of the steam heating tube changes, immediately execute 301 to determine whether the gas phase temperature in the absorption tower is within the gas phase temperature tolerance range. In S3, when it is necessary to adjust the spray water volume per unit time in the quench tower, the spray water pipe control valve of the quench tower is adjusted by the current gas phase temperature in the absorption tower and the current spray water volume per unit time in the quench tower. Specifically: S304: The opening degree of the quench tower spray water pipe control valve is divided into six different opening degree values ​​from 0 to 5. The current opening degree of the quench tower spray water pipe control valve is obtained, and the judgment result of whether the spray water volume per unit time needs to be increased or decreased is obtained. If the judgment result of the adjustment of the spray water volume per unit time is to increase, the control valve is adjusted to move one opening degree in the direction of increasing the flow rate of the quench tower spray water pipe. If the judgment result of the adjustment of the spray water volume per unit time is to decrease, the control valve is adjusted to move one opening degree in the direction of decreasing the flow rate of the quench tower spray water pipe. S305: Determine whether the opening degree of the control valve for the spray water pipe of the quench tower has changed. If the opening degree of the control valve for the spray water pipe of the quench tower has changed, repeat S301.

2. The method for controlling the production of high-concentration formaldehyde solution according to claim 1, characterized in that: In S1, a temperature sensor is installed on the ionized water supply tank to continuously monitor the deionized water temperature, specifically: S101: Obtain the liquid level in the deionized water supply tank, obtain the water temperature at the highest point of the deionized water in the supply tank, and obtain the water temperature at the lowest point of the deionized water in the supply tank. S102: The average of the lowest and highest temperatures of the deionized water in the supply tank is used to obtain the current ionized water temperature. The measurement time interval is set, and multiple current ionized water temperatures are measured according to the measurement time interval. An ionized water temperature observation database is established, and all current ionized water temperatures are arranged in chronological order and stored in the ionized water temperature observation database.

3. The method for controlling the production of high-concentration formaldehyde solution according to claim 1, characterized in that: In S2, the need to preheat the deionized water in the supply tank is determined by the liquid phase temperature and its tolerance range. Specifically: S201: Obtain the liquid phase temperature in the absorption tower, obtain the liquid phase temperature tolerance range, and determine whether the liquid phase temperature in the absorption tower is within the liquid phase temperature tolerance range. If the liquid phase temperature in the absorption tower is within the liquid phase temperature tolerance range, set a judgment interval period and repeat the judgment according to the judgment interval period. If the liquid phase temperature in the absorption tower is not within the liquid phase temperature tolerance range, execute S202. S202: Obtain the minimum value of the liquid phase temperature tolerance range, and determine whether the liquid phase temperature in the absorption tower is less than or equal to the minimum value of the liquid phase temperature tolerance range. If the liquid phase temperature in the absorption tower is less than or equal to the minimum value of the liquid phase temperature tolerance range, the result is that the deionized water in the supply water tank needs to be preheated. If the liquid phase temperature in the absorption tower is greater than the minimum value of the liquid phase temperature tolerance range, then execute S203. S203: Obtain the highest value of the liquid phase temperature tolerance range and determine whether the liquid phase temperature in the absorption tower is greater than or equal to the highest value of the liquid phase temperature tolerance range. If the liquid phase temperature in the absorption tower is greater than or equal to the highest value of the liquid phase temperature tolerance range, an alarm will be activated to notify the management personnel to cool down the deionized water in the supply water tank. If the liquid phase temperature in the absorption tower is less than the highest value of the liquid phase temperature tolerance range, an alarm will be activated to notify the management personnel that the liquid phase temperature in the absorption tower is malfunctioning and needs to be repaired in time.

4. The method for controlling the production of high-concentration formaldehyde solution according to claim 1, characterized in that: In S2, when preheating of deionized water is required, the control valve of the steam heating pipe is adjusted by the current liquid phase temperature in the absorption tower and the current deionized water temperature in the supply water tank. Specifically: S204: Obtain the current liquid phase temperature in the absorption tower, obtain the minimum and maximum values ​​of the liquid phase temperature tolerance range, sum the minimum and maximum values ​​of the liquid phase temperature tolerance range and take the average value to obtain the target temperature, and obtain the temperature difference to be raised by subtracting the target temperature from the current liquid phase temperature in the absorption tower. S205: Obtain the current deionized water temperature in the supply water tank, and sum the difference between the current deionized water temperature in the supply water tank and the temperature to be raised to obtain the preheating temperature; S206: Open the control valve of the steam heating tube until the temperature of the deionized water in the supply water tank reaches the preheating temperature, then close the control valve of the steam heating tube.

5. A high-concentration formaldehyde solution production control system, applied to the high-concentration formaldehyde solution production control method according to any one of claims 1-4, characterized in that, Includes the following modules: The deionized water temperature monitoring module has a deionized water supply tank installed at one end of the deionized water inlet pipe of the absorption tower. A steam heating pipe is wound and installed on the surface of the deionized water supply tank to heat the deionized water in the tank. Both ends of the steam heating pipe are fixedly connected to the high-temperature gas inlet pipe of the quench tower. A one-way control valve is installed at both ends of the steam heating pipe. A temperature sensor is installed on the deionized water supply tank to continuously monitor the deionized water temperature. The liquid phase temperature control module acquires the liquid phase temperature in the absorption tower, sets the liquid phase temperature tolerance range, and determines whether the deionized water in the supply water tank needs to be preheated based on the liquid phase temperature and the liquid phase temperature tolerance range. When preheating of deionized water is required, the control valve of the steam heating pipe is adjusted based on the current liquid phase temperature in the absorption tower and the current deionized water temperature in the supply water tank. The gas phase temperature control module acquires the gas phase temperature inside the absorption tower, sets the gas phase temperature tolerance range, and determines whether it is necessary to adjust the spray water volume per unit time of the quench tower based on the gas phase temperature and the gas phase temperature tolerance range. When it is necessary to adjust the spray water volume per unit time of the quench tower, the spray water pipe control valve of the quench tower is adjusted based on the current gas phase temperature inside the absorption tower and the current spray water volume per unit time of the quench tower.

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