Oxidative absorption system and method for producing acrylic acid from propylene

Abstract

The present invention discloses a propylene-to-acrylic acid oxidation absorption system and a method thereof. The system is characterized by comprising a propylene vaporization tower, a first oxidation reactor, a second oxidation reactor and a three-in-one tower, wherein the top portion of the propylene vaporization tower is provided with a mixing superheater, the top portion outlet of the mixing superheater, the top portion inlet of the oxidation reactor and the bottom portion outlet of the second oxidation reactor are sequentially connected in series with the lower end inlet of the three-in-one tower, a product steam generator is arranged between the second oxidation reactor and the three-in-one tower, and an upper portion washing water steam stripping section, a middle portion acrylic acid absorption section and a lower portion reactant cooling section are arranged inside the three-in-one tower. The system and the method have the following advantages that the finally obtained acrylic acid solution has characteristics of high concentration and low impurity content, and characteristics of safety, environmental protection, energy saving and effective oxidation catalyst protecting are provided.

Description

technical field [0001] The invention relates to an oxidation absorption system and method for producing acrylic acid from propylene. Background technique [0002] The production of acrylic acid by oxidation of propylene is a mature process. Acrylic acid is usually produced from propylene through a two-step oxidation reaction. The oxidative absorption of propylene is the basis for the subsequent purification of acrylic acid. The effect of oxidation absorption and the level of energy consumption determine whether the technology is advanced. In the process of oxidation and absorption, the conventional method is that the raw material liquid propylene is vaporized by a kettle evaporator and then superheated by a shell-and-tube superheater, then mixed with water vapor and air, and then enters the first and second oxidation reactors successively, and undergoes two-stage oxidation. The gas after reaction to generate acrylic acid is sent to the quenching tower, the top of the quen...

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Problems solved by technology

[0003] 1. The raw material liquid propylene feed is directly vaporized by the kettle-type vaporizer. The polymer produced during the storage of propylene is not removed and will be vaporized and brought into the reactor. The polymer adheres to the surface of the catalyst, affecting the yield of the oxidation reaction and reducing Catalyst life

[0004] 2. Propylene vaporization, overheating, and mixing need to pass through multiple devices connected in sequence. Due to the flammability and explosiveness of propylene, the more devices passed through, the more connection points, the greater the risk of leakage and the higher the danger

[0005] 3. When the oxidation product is sent to the absorption tower for absorption, desalted water is used as the cooling absorption medium at the top of the tower, so a large amount of desalted water is consumed, and a large amount of sewage containing organic matter will be discharged in the subsequent acrylic acid refining process, polluting the environment

[0006] 4. The temperature of the exhaust gas discharged from the top of the tower is low, and the calorific value is low when it is sent to incineration, resulting in high incineration cost

[0007] 5. There are no tower internals suitable for acrylic acid absorption. Conventional tower internals lead to poor absorption effect and prone to tray flooding. Therefore, it is urgent to develop high-efficiency tower internals suitable for acrylic acid absorption.

However, since the tail gas at the top of the oxidation absorption tower contains a variety of organic impurities, direct return to the reactor will reduce the life of the oxidation catalyst, resulting in an increase in production costs

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