Ethylene oxide absorption dealdehyding system

Abstract

The utility model discloses an ethylene oxide absorption dealdehyding system in the field of dealdehyding, which comprises an ethylene oxide absorption tower, and the bottom of the ethylene oxide absorption tower is connected with a desalting delivery pump, a 20% sodium hydroxide solution metering pump and a dealdehyding buffer tank through pipelines. The dealdehyding buffer tank is further connected with a sodium hydrogen sulfite solution metering pump and a quenching stripping tower through pipelines, the top of the dealdehyding buffer tank is provided with a first EO re-absorption tower connecting pipe, the desalting delivery pump is connected with a cooler through a pipeline, the cooler is connected with an ethylene oxide absorption tower through a pipeline, and the ethylene oxide absorption tower is connected with a second EO re-absorption tower through a pipeline. And desalted water equipment is mounted on a pipeline between the cooler and the ethylene oxide absorption tower through a three-way valve. The dealdehyding resin is adopted for dealdehyding of the lean absorption water part, sodium sulfite is added to the quenching section of the EO absorption tower for dealdehyding, and then flash evaporation is performed, so that the content of aldehyde in the lean absorption water can be effectively reduced, and the content of aldehyde in an EO absorption system can be effectively reduced.

Description

Technical Field

[0001] The utility model relates to the field of aldehyde removal, in particular to an ethylene oxide absorption and aldehyde removal system. Background Technique

[0002] The ethylene oxide / ethylene glycol plant adopts the SHELL-MASTER process technology to produce ethylene glycol and ethylene oxide. Ethylene and oxygen react in a certain proportion, with methane (nitrogen) as the stabilizer gas, to synthesize ethylene oxide under the action of a silver catalyst. During the ethylene oxidation process, multiple side reactions occur, including the side reactions of EO isomerization to acetaldehyde and ethylene oxidation to formaldehyde. There are trace amounts of acetaldehyde and formaldehyde in the product. Most of the impurities such as aldehydes in the reaction product gas are absorbed in the quench section of the EO absorption tower. In an acidic environment, a large amount of aldehyde substances are easily generated in the aqueous solution of ethylene oxide. Ethylene glycol and diethylene glycol are oxidized or dehydrogenated under the catalysis of Fe2O3 to produce hydroxyacetaldehyde (CH2OHCHO). Aldehydes are easily oxidized to acids and dissolve in water, resulting in equipment corrosion. If the aldehyde content generated during the reaction process is too high, it will directly affect the quality of ethylene oxide. GB / T 13098-2006 "Ethylene Oxide for Industrial Use" requires that the aldehyde content of the ethylene oxide product of the first-class product be controlled below 30 ppm.

[0003] Aldehydes are absorbed by process water together with EO and accumulate continuously with the circulation of process water and EO in the device. Therefore, those skilled in the art have provided an ethylene oxide absorption and aldehyde removal system to solve the problems raised in the above background technique. Summary of the Invention

[0004] The purpose of the utility model is to provide an ethylene oxide absorption and aldehyde removal system to solve the problems raised in the above background technique.

[0005] To achieve the above purpose, the utility model provides the following technical solutions:

[0006] An ethylene oxide absorption and aldehyde removal system includes an ethylene oxide absorption tower. The bottom of the ethylene oxide absorption tower is connected with a desalination transfer pump, a 20% sodium hydroxide solution metering pump, and an aldehyde removal buffer tank through pipelines. The aldehyde removal buffer tank is also connected with a sodium bisulfite solution metering pump and a quench and stripping tower through pipelines. A first EO reabsorption tower connection pipe is installed at the top of the aldehyde removal buffer tank. A cooler is connected to the desalination transfer pump through a pipeline. The cooler is connected to the ethylene oxide absorption tower through a pipeline, and a desalted water device is installed through a three-way valve on the pipeline between the cooler and the ethylene oxide absorption tower. The top of the ethylene oxide absorption tower is connected with a lean absorption water pipe. A first aldehyde removal resin tank is connected in parallel to the lean absorption water pipe. Two pipelines are respectively connected to a second aldehyde removal resin tank and a third aldehyde removal resin tank on one side of the first aldehyde removal resin tank on the lean absorption water pipe.

[0007] As a further solution of the present utility model: one side of the second aldehyde removal resin tank is connected to an EO reabsorption tower through the second EO reabsorption tower connecting pipe, and the third aldehyde removal resin tank is connected to a tail gas absorption tower through a tail gas absorption tower connecting pipe.

[0008] As a further solution of the present utility model: a circulating gas conveying pipe and a rich absorption water pipe are connected to the ethylene oxide absorption tower from bottom to top.

[0009] As a further solution of the present utility model: an EO reabsorption tower is installed on the first EO reabsorption tower connecting pipe installed at the top of the aldehyde removal buffer tank.

[0010] As a further solution of the present utility model: on the pipelines on both sides of the cooler, a bypass cooling valve parallel to the cooler is connected through a pipeline.

[0011] Compared with the prior art, the beneficial effects of the present utility model are:

[0012] In the present utility model, the lean absorption water part uses aldehyde removal resin for aldehyde removal, and sodium sulfite is added to the quench section of the EO absorption tower for aldehyde removal and then flash evaporation, which can effectively reduce the aldehyde content in the lean absorption water and can effectively reduce the aldehyde content in the EO absorption system. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a system diagram of the present utility model.

[0014] In the figure: 1. Aldehyde removal buffer tank; 2. Sodium bisulfite solution metering pump; 3. Desalted water delivery pump; 4. 20% sodium hydroxide solution metering pump; 5. Desalted water equipment; 6. Circulating gas conveying pipe; 7. Rich absorption water pipe; 8. First aldehyde removal resin tank; 9. Second aldehyde removal resin tank; 10. First EO reabsorption tower connecting pipe; 11. Tail gas absorption tower connecting pipe; 12. Third aldehyde removal resin tank; 13. Quench and stripping tower connecting pipe; 14. Second EO reabsorption tower connecting pipe; 15. Cooler; 16. Bypass cooling valve; 17. Ethylene oxide absorption tower. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present utility model.

[0016] Please refer to Figure 1, in the embodiment of the present utility model, an ethylene oxide absorption and aldehyde removal system includes an ethylene oxide absorption tower 17. The bottom of the ethylene oxide absorption tower 17 is connected by pipelines to a desalted water transfer pump 3, a 20% sodium hydroxide solution metering pump 4, and an aldehyde removal buffer tank 1. The aldehyde removal buffer tank 1 is also connected by a pipeline to a sodium bisulfite solution metering pump 2 and a quench stripping tower. A first EO reabsorption tower connection pipe 10 is installed at the top of the aldehyde removal buffer tank 1. A cooler 15 is connected by a pipeline to the desalted water transfer pump 3. The cooler 15 is connected to the ethylene oxide absorption tower 17 by a pipeline, and a desalted water device 5 is installed through a three-way valve on the pipeline between the cooler 15 and the ethylene oxide absorption tower 17. The top of the ethylene oxide absorption tower 17 is connected by a pipeline to a lean absorption water pipe. A first aldehyde removal resin tank 8 is connected in parallel to the lean absorption water pipe. On one side of the first aldehyde removal resin tank 8 on the lean absorption water pipe, a second aldehyde removal resin tank 9 and a third aldehyde removal resin tank 12 are respectively connected by two pipelines.

[0017] By adopting the above technical solution, part of the lean absorption water is de-aldehydeized by using aldehyde removal resin. Sodium sulfite is added for aldehyde removal in the quench section of the EO absorption tower and then flash evaporation is carried out. The aldehyde content in the lean absorption water of ethylene oxide is about 20 ppm. After the lean absorption water absorbs ethylene oxide in the recycle gas, the aldehyde content in the rich absorption water increases by 4 - 5 ppm. Reducing the aldehyde content in the lean absorption water can effectively reduce the aldehyde content in the EO absorption system.

[0018] Among them, one side of the second aldehyde removal resin tank 9 is connected to an EO reabsorption tower through a second EO reabsorption tower connection pipe 14. The third aldehyde removal resin tank 12 is connected to a tail gas absorption tower through a tail gas absorption tower connection pipe 11. A recycle gas transfer pipe 6 and a rich absorption water pipe 7 are connected to the ethylene oxide absorption tower 17 from bottom to top.

[0019] Among them, an EO reabsorption tower is installed on the first EO reabsorption tower connection pipe 10 installed at the top of the aldehyde removal buffer tank 1. On the pipelines on both sides of the cooler 15, a bypass cooling valve 16 parallel to the cooler 15 is connected by a pipeline.

[0020] By adopting the above technical solution, by controlling the opening and closing of the bypass cooling valve 16, when cooling is not required, the circulating water can directly pass through the bypass cooling valve 16, improving the efficiency.

[0021] The above is only a preferred specific embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present utility model, according to the technical solution of the present utility model and its inventive concept, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present utility model.

Claims

1. An ethylene oxide absorption and dealdehyde removal system, comprising an ethylene oxide absorption tower (17), characterized in that: The bottom of the ethylene oxide absorption tower (17) is connected to a desalting delivery pump (3), a 20% sodium hydroxide solution metering pump (4) and a dealdehyde buffer tank (1) via a pipeline; the dealdehyde buffer tank (1) is also connected to a sodium bisulfite solution metering pump (2) and a quenching stripping tower via a pipeline; an EO reabsorption tower connecting pipe 1 (10) is installed on the top of the dealdehyde buffer tank (1); the desalting delivery pump (3) is connected to a cooler (15) via a pipeline; the cooler (15) is connected to the ethylene oxide absorption tower (17) via a pipeline; and a desalting water device (5) is installed on the pipeline between the cooler (15) and the ethylene oxide absorption tower (17) via a three-way valve; The top of the ethylene oxide absorption tower (17) is connected to a lean absorption water pipe via a pipeline, and the lean absorption water pipe is connected in parallel to a formaldehyde-removing resin tank one (8). The lean absorption water pipe is located on one side of the formaldehyde-removing resin tank one (8) and is connected to a formaldehyde-removing resin tank two (9) and a formaldehyde-removing resin tank three (12) via two pipelines respectively.

2. The ethylene oxide absorption and dealdehyde removal system according to claim 1, characterized in that: One side of the formaldehyde-removing resin tank 2 (9) is connected to the EO reabsorption tower via the EO reabsorption tower connecting pipe 2 (14), and the upper side of the formaldehyde-removing resin tank 3 (12) is connected to the tail gas absorption tower via the tail gas absorption tower connecting pipe (11).

3. The ethylene oxide absorption and dealdehyde removal system according to claim 1, characterized in that: The ethylene oxide absorption tower (17) is connected from bottom to top with a circulating gas delivery pipe (6) and a rich absorption water pipe (7).

4. The ethylene oxide absorption and dealdehyde removal system according to claim 1, characterized in that: An EO reabsorption tower is installed on the EO reabsorption tower connecting pipe 1 (10) installed on the top of the dealdehyde buffer tank (1).

5. The ethylene oxide absorption and dealdehyde removal system according to claim 1, characterized in that: The pipelines on both sides of the cooler (15) are connected via pipelines to a cooling valve (16) connected in parallel with the cooler (15).

Images