Formaldehyde filler absorption tower

Abstract

The utility model relates to the technical field of formaldehyde production, in particular to a formaldehyde packing absorption tower which is matched with a water cooling system. The water cooling system comprises a circulating pump, a main pipeline, a first heat exchanger, a desalted water branch pipeline, a second heat exchanger and a cold water branch pipeline. The inlet end and the outlet end of the main pipeline are communicated with the formaldehyde filler absorption tower to form a circulation loop. The circulating pump, the first heat exchanger and the second heat exchanger are sequentially connected to the main pipeline in series in the circulation direction. The desalted water branch pipe, the desalted water channel and the cold water branch pipeline are respectively used for circulating desalted water and cooling water for the steam boiler, and are correspondingly connected to the first heat exchanger and the second heat exchanger in a one-to-one manner. Therefore, on one hand, the heated liquid-phase formaldehyde is fully subjected to heat exchange, so that the formaldehyde filler absorption tower is ensured to keep good working performance for a long time; and on the other hand, the original waste heat is reasonably utilized, the heat production efficiency of the steam boiler is effectively improved, and the cooling water consumption and the total electric energy consumption are both reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of formaldehyde production, in particular to a formaldehyde filling absorption tower. Background Art

[0002] In the process of preparing formaldehyde, the high-temperature formaldehyde gas needs to be absorbed and solidified with the help of liquid formaldehyde. The entire absorption process is carried out in a formaldehyde-filled absorption tower. The high-temperature formaldehyde gas is cooled, while the liquid formaldehyde heats up (over 60°C) due to the absorption of a large amount of heat.

[0003] In order to ensure that the formaldehyde packing absorption tower always maintains good working performance during the production process and is conducive to the overall thermal balance of the absorption system, the liquid formaldehyde needs to be continuously cooled so that its temperature is always kept below 50°C. In view of this, in the prior art, the formaldehyde packing absorption tower is equipped with a water cooling system (such as Figure 1 As shown in ), it mainly uses the heat exchanger H-501 to exchange heat between the heated liquid formaldehyde and the cooling water in the cooling tower, and the heated cooling water flows back to the cooling tower to dissipate heat and cool for recycling. Although this solution can reduce the temperature of the liquid formaldehyde in the formaldehyde packing absorption tower to a certain extent, the heat exchange process is slightly insufficient, the temperature reduction effect of the liquid formaldehyde is relatively limited, and the water cooling system consumes a lot of electricity and water during operation, and the cooling cost remains high. More importantly, a large amount of heat is lost through the cooling tower without being reasonably utilized, and the economic benefits are low. Therefore, technical personnel are urgently needed to solve the above problems. Summary of the invention

[0004] Therefore, in view of the above-mentioned existing problems and defects, the designers of the present invention collected relevant information, conducted multiple evaluations and considerations, and continued to experiment and modify the formaldehyde packing absorption tower after many years of R&D experience in this industry, which ultimately led to the emergence of the formaldehyde packing absorption tower.

[0005] In order to solve the above technical problems, the utility model relates to a formaldehyde packing absorption tower, including a tower body and a stainless steel packing. The stainless steel packing is filled in the tower body and immersed in liquid formaldehyde. In the process of preparing formaldehyde, high-temperature gaseous formaldehyde is transported to the tower body and is cooled and absorbed by the liquid formaldehyde, and the liquid formaldehyde is heated due to the endothermic process. In addition, the formaldehyde packing absorption tower also includes a water cooling system. The water cooling system is used to perform heat exchange and cooling operations on the heated liquid formaldehyde, and it includes a circulating pump, a main pipeline, a first heat exchanger, a desalted water branch pipeline, a second heat exchanger and a cold water branch pipeline. The inlet and outlet ends of the main pipeline are connected to the tower body to form a circulation loop. Along the circulation direction of the liquid formaldehyde, the circulating pump, the first heat exchanger and the second heat exchanger are connected in series to the main pipeline in sequence. The desalted water branch pipeline is used to circulate desalted water for the steam boiler, and it is connected to the first heat exchanger. The cold water branch pipe is used for circulating cooling water and is connected to the second heat exchanger.

[0006] As a further improvement of the technical solution disclosed in the utility model, the water cooling system also includes a first thermocouple thermometer, a second thermocouple thermometer, a third thermocouple thermometer and a fourth thermocouple thermometer. The first thermocouple thermometer and the second thermocouple thermometer are both assembled on the desalted water branch pipe and are respectively arranged upstream and downstream of the first heat exchanger. The third thermocouple thermometer and the fourth thermocouple thermometer are both assembled on the cold water branch pipe and are respectively arranged upstream and downstream of the second heat exchanger.

[0007] As a further improvement of the technical solution disclosed in the utility model, the water cooling system further includes a one-way valve. The one-way valve is assembled on the main pipeline and is located downstream of the circulation pump and upstream of the first heat exchanger.

[0008] As a further improvement of the technical solution disclosed in the utility model, the water cooling system also includes a pipeline filter. The pipeline filter is assembled on the main pipeline and is located upstream of the circulation pump.

[0009] As a further improvement of the technical solution disclosed in the utility model, the water cooling system also includes a flow control valve and a liquid level meter. The liquid level meter is placed in the water supply tank of the steam boiler. The flow control valve is assembled on the desalted water branch pipe, and its opening and closing degree is adjusted according to the water depth value of the water supply tank fed back by the liquid level meter.

[0010] During the formaldehyde preparation process, the circulation pump is kept in the started state, and the liquid formaldehyde that is immersed in the stainless steel filler and heated up by heat exchange with the high-temperature gaseous formaldehyde continuously circulates in the main pipeline under the action of the pumping force. When flowing through the first heat exchanger, it exchanges heat with the desalted water for the steam boiler once, thereby realizing a cooling process. When flowing through the second heat exchanger, it exchanges heat with the cooling water twice, thereby realizing a secondary cooling process. The temperature of the liquid formaldehyde can be reduced to below the design value. At the same time, the desalted water for the steam boiler is heated up due to heat exchange, and the calorific value is increased, thereby effectively increasing the gas production of the steam boiler.

[0011] In practical applications, the formaldehyde packing absorption tower disclosed in the utility model has achieved at least the following beneficial technical effects, specifically:

[0012] 1) When the heated liquid formaldehyde circulates along the main pipeline, it flows through the first heat exchanger and the second heat exchanger in sequence, and respectively exchanges heat with the desalted water and cooling water used in the steam boiler to achieve the primary cooling process and the secondary cooling process. The liquid formaldehyde can be fully heat exchanged, so that the temperature of the liquid formaldehyde refluxed to the formaldehyde packing absorption tower is reduced to below 50°C, thereby ensuring that the formaldehyde packing absorption tower maintains good working performance in the long term, which means that the preparation efficiency of formaldehyde is significantly improved;

[0013] 2) After sufficient heat exchange, the temperature of the desalted water used in the steam boiler is significantly increased, and the calorific value is increased. In this way, on the one hand, a large amount of heat that was originally wasted is effectively utilized, effectively improving the heat production efficiency of the steam boiler; on the other hand, under the premise of a certain total heat exchange rate, the amount of cooling water that needs to be transported to the second heat exchanger and the total power consumption are significantly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 It is a structural schematic diagram of a formaldehyde packing absorption tower in the prior art.

[0016] Figure 2 It is a structural schematic diagram of the first embodiment of the formaldehyde packing absorption tower disclosed in the utility model.

[0017] Figure 3 It is a structural schematic diagram of a second embodiment of the formaldehyde packing absorption tower disclosed in the utility model.

[0018] Figure 4 It is a structural schematic diagram of a third embodiment of the formaldehyde packing absorption tower disclosed in the utility model.

[0019] 1-tower body; 2-stainless steel filler; 3-water cooling system; 31-circulating pump; 32-main pipeline; 33-first heat exchanger; 34-desalted water branch pipeline; 35-second heat exchanger; 36-cold water branch pipeline; 37-first thermocouple thermometer; 38-second thermocouple thermometer; 39-third thermocouple thermometer; 310-fourth thermocouple thermometer; 311-check valve; 312-pipeline filter; 313-flow control valve; 314-liquid level meter. DETAILED DESCRIPTION

[0020] The following is a detailed description of the contents disclosed in the utility model in conjunction with specific embodiments. According to common knowledge, the formaldehyde packing absorption tower is mainly composed of a tower body 1 and a stainless steel packing 2. The stainless steel packing 2 is filled in the tower body 1 and immersed in liquid formaldehyde. During the process of preparing formaldehyde, the high-temperature gaseous formaldehyde is transported to the tower body 1 and is cooled and absorbed by the liquid formaldehyde. The liquid formaldehyde is heated up due to the endothermic process (such as Figure 2 ).

[0021] Figure 2 The schematic diagram of the structure of the first embodiment of the formaldehyde packing absorption tower disclosed in the utility model shows that the formaldehyde packing absorption tower is equipped with a water cooling system 3, which is used to perform heat exchange and cooling operations on the heated liquid formaldehyde. The water cooling system 3 is mainly composed of a circulation pump 31, a main pipeline 32, a first heat exchanger 33, a desalted water branch pipeline 34, a second heat exchanger 35 and a cold water branch pipeline 36. Among them, the inlet end and the outlet end of the main pipeline 32 are connected to the tower body 1 to form a circulation loop. Along the circulation direction of the liquid formaldehyde, the circulation pump 31, the first heat exchanger 33 and the second heat exchanger 35 are connected in series to the main pipeline 32 in sequence. The desalted water branch pipeline 34 is used to circulate desalted water for the steam boiler, and it is connected to the first heat exchanger 33. The cold water branch pipeline 36 is used to circulate cooling water, and it is connected to the second heat exchanger 35.

[0022] In the formaldehyde preparation process, the circulation pump 31 is kept in the started state, and the liquid formaldehyde that is immersed in the stainless steel filler and heated by heat exchange with the high-temperature gaseous formaldehyde continuously circulates in the main pipeline 32 under the action of the pumping force. When flowing through the first heat exchanger 33, it exchanges heat with the desalted water for the steam boiler once, thereby realizing a cooling process. When flowing through the second heat exchanger 35, it exchanges heat with the cooling water twice, thereby realizing a secondary cooling process. The temperature of the liquid formaldehyde is reduced to below the design value. At the same time, the heated desalted water for the steam boiler is transported to the steam boiler for producing steam, and the calorific value is increased, thereby effectively increasing the gas production of the steam boiler.

[0023] By setting up the above technical scheme, the heated liquid formaldehyde flows through the first heat exchanger 33 and the second heat exchanger 35 in sequence during the process of circulating along the main pipeline 32, and respectively exchanges heat with the desalted water and cooling water for the steam boiler to achieve a primary cooling process and a secondary cooling process. The liquid formaldehyde can be fully heat exchanged, so that the temperature of the liquid formaldehyde refluxed into the tower body 1 is reduced to below 50°C, thereby ensuring that the formaldehyde packing absorption tower maintains good working performance in the long term, which means that the preparation efficiency of formaldehyde is significantly improved;

[0024] Here, it is also necessary to explain that after sufficient heat exchange, the temperature of the desalted water used in the steam boiler is significantly increased and the calorific value is increased. In this way, on the one hand, a large amount of originally wasted heat is effectively utilized, which effectively improves the heat production efficiency of the steam boiler; on the other hand, under the premise of a certain total heat exchange amount, the amount of cooling water to be transported to the second heat exchanger 35 and the total electricity consumption are significantly reduced.

[0025] In the actual operation of the formaldehyde packing absorption tower, the circulating cooling water and cooling load are effectively saved, low energy is truly recovered and comprehensively utilized, the investment cost is recovered in a relatively short period of time, and green and low-carbon production is achieved. The specific operation statistics and economic calculation statistics are as follows:

[0026] Operation status: 200 tons of formaldehyde solution at 60℃ are cooled to 58℃ within one hour, and at the same time, the desalted water is heated from 25℃ (flow rate 20 tons / h) to 45℃.

[0027] Tm=(33-15) / ln(33 / 15)=22.83℃

[0028] Q=20*1000*1000*4.2 / 3600=460000W

[0029] Economic calculation: Based on 8,000 hours of operation per year and a boiler desalted water flow rate of 20 tons / h

[0030] The annual steam increase is:

[0031] 20*20*1000*8000 / (539*1000)=5937 tons

[0032] Based on the steam price of 200 yuan per ton, the cost savings are: 5937*200=1187384 yuan, or 1.18 million yuan.

[0033] Furthermore, by Figure 2 It can also be clearly seen that the water cooling system 3 is further provided with a first thermocouple thermometer 37, a second thermocouple thermometer 38, a third thermocouple thermometer 39 and a fourth thermocouple thermometer 310. The first thermocouple thermometer 37 and the second thermocouple thermometer 38 are both assembled on the desalted water branch pipe 34, and are respectively arranged upstream and downstream of the first heat exchanger 33. The third thermocouple thermometer 39 and the fourth thermocouple thermometer 310 are both assembled on the cold water branch pipe 36, and are respectively arranged upstream and downstream of the second heat exchanger 35. In this way, in the process of producing formaldehyde using the formaldehyde packing absorption tower, the first thermocouple thermometer 37 and the second thermocouple thermometer 38 are respectively used to measure the temperature of the liquid formaldehyde before and after flowing through the first heat exchanger 33, and calculate the temperature difference T1, while the third thermocouple thermometer 39 and the fourth thermocouple thermometer 310 are respectively used to measure the temperature of the desalted water for steam boilers before and after flowing through the first heat exchanger 33, and calculate the temperature difference T2. By comparing the temperature differences T1 and T2 with their respective set standard values, the temperature drop effect of the liquid formaldehyde after one heat exchange and the increase in the calorific value of the desalted water for steam boilers can be indirectly known, and it can also indirectly reflect whether the operating status of the first heat exchanger 33 is normal.

[0034] Figure 3 The schematic diagram of the structure of the second embodiment of the formaldehyde packing absorption tower disclosed in the utility model is shown. It can be seen that the difference between the second embodiment and the first embodiment is that the water cooling system 3 is additionally provided with a one-way valve 311 and a pipeline filter 312. Among them, the one-way valve 311 is assembled on the main pipeline 32 and is located downstream of the circulation pump 31 and upstream of the first heat exchanger 33. The pipeline filter 312 is also assembled on the main pipeline 32 and is located upstream of the circulation pump 31. In the actual operation of the formaldehyde packing absorption tower, the presence of the one-way valve 311 can effectively prevent the liquid formaldehyde from flowing back to the circulation pump 31, eliminate the rotation resistance caused by the reverse flow, and ensure that the circulation pump 31 always maintains good working performance (mainly reflected in flow rate, head and pumping efficiency). The pipeline filter 312 can effectively filter the impurities of the liquid formaldehyde entering the circulation pump 31 through the main pipeline 32, thereby avoiding the narrowing or blocking of the circulation pump 31 or the main pipeline 32 due to the entry of large particle impurities.

[0035] Figure 4 The schematic diagram of the structure of the third embodiment of the formaldehyde packing absorption tower disclosed in the utility model is shown. It can be seen that the difference between the third embodiment and the second embodiment is that the water cooling system 3 is additionally provided with a flow control valve 313 and a liquid level meter 314. The liquid level meter 314 is placed in the water supply tank of the steam boiler. The flow control valve 313 is assembled on the desalted water branch pipe 34, and its opening and closing degree can be adjusted according to the measurement result of the liquid level meter 314. In the actual operation of the formaldehyde packing absorption tower, the liquid level meter 314 is used to monitor the water depth of the steam boiler water supply tank in real time, and when the water depth value is lower than the design value, the opening and closing degree of the flow control valve 313 is increased accordingly; and when the water depth value exceeds the design value, the opening and closing degree of the flow control valve 313 is reduced accordingly, so that the water depth of the steam boiler water supply tank is always maintained within a reasonable value range, thereby effectively avoiding the overflow due to excessive desalted water supply to the steam boiler or the occurrence of the phenomenon of "empty burning" of the steam boiler due to insufficient water supply.

[0036] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A formaldehyde filling absorption tower, comprising a tower body and a stainless steel filling; the stainless steel filling is filled in the tower body and immersed in liquid formaldehyde; in the process of preparing formaldehyde, high-temperature gaseous formaldehyde is transported to the tower body and is cooled and absorbed by the liquid formaldehyde, and the liquid formaldehyde is heated due to the endothermic process, characterized in that: It also includes a water cooling system; the water cooling system is used to perform heat exchange and cooling operations on the heated liquid formaldehyde, and includes a circulation pump, a main pipeline, a first heat exchanger, a desalted water branch pipeline, a second heat exchanger and a cold water branch pipeline; the inlet and outlet ends of the main pipeline are both connected to the tower body to form a circulation loop; along the circulation direction of the liquid formaldehyde, the circulation pump, the first heat exchanger and the second heat exchanger are connected in series to the main pipeline in sequence; the desalted water branch pipeline is used to circulate desalted water for the steam boiler, and it is connected to the first heat exchanger in bypass; the cold water branch pipeline is used to circulate cooling water, and it is connected to the second heat exchanger in bypass.

2. The formaldehyde packing absorption tower according to claim 1, characterized in that: The water cooling system also includes a first thermocouple thermometer, a second thermocouple thermometer, a third thermocouple thermometer and a fourth thermocouple thermometer; the first thermocouple thermometer and the second thermocouple thermometer are both assembled on the desalted water branch pipeline, and are respectively arranged upstream and downstream of the first heat exchanger; the third thermocouple thermometer and the fourth thermocouple thermometer are both assembled on the cold water branch pipeline, and are respectively arranged upstream and downstream of the second heat exchanger.

3. The formaldehyde packing absorption tower according to claim 1, characterized in that: The water cooling system further includes a one-way valve; the one-way valve is assembled on the main pipeline and is located downstream of the circulation pump and upstream of the first heat exchanger.

4. The formaldehyde packing absorption tower according to claim 3, characterized in that: The water cooling system also includes a pipeline filter; the pipeline filter is assembled on the main pipeline and is located upstream of the circulation pump.

5. The formaldehyde packing absorption tower according to any one of claims 1 to 4, characterized in that: The water cooling system also includes a flow control valve and a liquid level meter; the liquid level meter is placed in the water supply tank of the steam boiler; the flow control valve is assembled on the desalted water branch pipeline, and its opening and closing degree is adjusted according to the water depth value of the water supply tank fed back by the liquid level meter.

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