CN-121988071-A - Sodium removal method and system for waste alkali butter

CN121988071ACN 121988071 ACN121988071 ACN 121988071ACN-121988071-A

Abstract

The application relates to a sodium removal method of waste alkali butter, which comprises the following steps of fully mixing waste alkali butter with acetic acid solution to obtain a mixture, separating the mixture to obtain an oil phase and a water phase, and collecting the oil phase to obtain the sodium-removed butter. According to the application, acetic acid is used as a sodium removing agent, so that the tendency of sodium ions to diffuse into an acetic acid solution can be enhanced, and the extraction efficiency of water on sodium is remarkably improved. Meanwhile, the biodegradability of the acetic acid is good, so that the subsequent treatment process of the water phase is easier after the phase separation. The water phase can be directly discharged into a sewage biochemical treatment field or discharged into a waste alkali oxidation reactor. Will not affect the existing wastewater treatment facilities.

Inventors

YI KE
WU BOYU

Assignees

中国石油天然气集团有限公司
中国寰球工程有限公司

Dates

Publication Date: 20260508
Application Date: 20241107

Claims (10)

1. A method for removing sodium from waste alkali butter, which is characterized by comprising the following steps: fully mixing waste alkali butter and acetic acid solution to obtain a mixture; Phase-separating the mixture to obtain an oil phase and a water phase; And collecting the oil phase to obtain the butter after sodium removal.
2. The method for removing sodium from waste alkali butter according to claim 1, wherein the pH of the acetic acid solution is 3-5.
3. The method of claim 1, wherein the waste butter is thoroughly mixed with the acetic acid solution, and the waste butter is mixed with the acetic acid solution by a static mixer.
4. The method for the sodium removal of spent caustic butter according to claim 1, characterized in that the phase separation is performed by a disk centrifuge.
5. A sodium removal system for spent caustic butter, the sodium removal system comprising: Acetic acid holding vessel, desalted water holding vessel and waste alkali butter holding vessel; The acetic acid solution storage tank is communicated with the acetic acid solution storage tank, and the desalted water storage tank is communicated with the acetic acid solution storage tank; the waste alkali butter storage tank is communicated with the mixer, and the acetic acid solution storage tank is communicated with the mixer; A buffer tank, the mixer being in communication with the buffer tank; The buffer tank is communicated with the phase separation device; The device comprises an oil phase storage tank and a water phase storage tank, wherein the phase separation device is communicated with the oil phase storage tank, and the phase separation device is communicated with the water phase storage tank.
6. The sodium removal system of spent caustic butter of claim 5, further comprising pH monitoring means for monitoring the pH of the acetic acid solution in the acetic acid solution storage tank.
7. The sodium removal system of spent caustic butter of claim 5, further comprising a first flow control valve and a second flow control valve, wherein the acetic acid storage tank is in communication with the acetic acid solution storage tank via the first flow control valve, and wherein the spent caustic butter storage tank is in communication with the acetic acid solution storage tank via the second flow control valve.
8. The spent caustic butter sodium removal system of claim 5, wherein the mixer is a static mixer.
9. The spent caustic soda butter sodium removal system of claim 5, wherein the phase separation device is a disk centrifuge.
10. The sodium removal system of spent caustic butter as defined in claim 5, further comprising a level sensing device for sensing a level of liquid in the acetic acid solution storage tank, And a third flow regulating valve is further arranged on a pipeline which is communicated with the acetic acid solution storage tank and the phase separation device, and the third flow regulating valve is in communication connection with the liquid level sensing device.

Description

Sodium removal method and system for waste alkali butter Technical Field The application relates to ethylene industry, in particular to waste alkali butter treatment. Background The pyrolysis gas during caustic washing produces liquid polymers that tend to take on a yellow viscous state and are therefore commonly referred to as "spent caustic butter". In ethylene units, the usual treatment process of waste alkali butter is to send the waste alkali butter along with waste alkali into a waste alkali oxidation unit, and separate the waste alkali butter from the waste alkali after treatment measures such as skimming, etc., and take the waste alkali butter as waste oil to be sold. However, as environmental protection policies become more and more strict, waste alkali butter belongs to dangerous waste and cannot be directly taken as a product for take-out. So that there is currently a need for further treatment of spent caustic butter. However, if waste alkali butter is sent to a fuel oil boiler or a waste liquid incinerator for incineration treatment, sodium ions in the waste alkali butter can cause ash accumulation in a convection flue of the boiler and corrosion of a furnace lining. If spent caustic butter is blended into pyrolysis gasoline for hydrotreating, sodium ions in the spent caustic butter can in turn lead to poisoning of the gasoline hydrogenation catalyst. Therefore, the key point of the resource utilization of the waste alkali butter is to remove sodium ions. At present, the method for removing sodium ions from the industrial and practical waste alkali butter adopts a water washing process, the waste alkali butter and water are mixed and kept stand, the long-time standing is carried out, the layering of an oil phase and a water phase is realized, and sodium ions in the waste alkali butter are transferred into the water phase, so that the purpose of removing sodium from the waste alkali butter is realized. The method has the limitations that an emulsion layer is easy to generate in the water washing process, an additional demulsifier is needed, the water phase and oil phase separation effect depends on the standing time, the longer the standing time is, the better the phase separation effect is, and according to the practical operation experience of a certain petrochemical factory in China, the standing time is more than 36 hours to achieve the sodium removal effect, so that the technology is large in equipment volume, occupied in units and large in investment. And continuous operation cannot be realized, and the limitation of the sodium removal process is large. Disclosure of Invention The embodiment of the application provides a sodium removal method and a sodium removal system for waste alkali butter, which aim to solve the technical problem of difficult sodium removal of waste alkali butter. In a first aspect, an embodiment of the present application provides a method for removing sodium from waste alkali butter, the method including the steps of: fully mixing waste alkali butter and acetic acid solution to obtain a mixture; Phase-separating the mixture to obtain an oil phase and a water phase; And collecting the oil phase to obtain the butter after sodium removal. In some embodiments of the application, the pH of the acetic acid solution is 3-5. In some embodiments of the application, the spent caustic butter is thoroughly mixed with the acetic acid solution, which is mixed by a static mixer. In some embodiments of the application, the phase separation is performed by a disk centrifuge. In a second aspect, an embodiment of the present application provides a sodium removal system for waste alkali butter, the sodium removal system for waste alkali butter comprising: Acetic acid holding vessel, desalted water holding vessel and waste alkali butter holding vessel; The acetic acid solution storage tank is communicated with the acetic acid solution storage tank, and the desalted water storage tank is communicated with the acetic acid solution storage tank; the waste alkali butter storage tank is communicated with the mixer, and the acetic acid solution storage tank is communicated with the mixer; A buffer tank, the mixer being in communication with the buffer tank; The buffer tank is communicated with the phase separation device; The device comprises an oil phase storage tank and a water phase storage tank, wherein the phase separation device is communicated with the oil phase storage tank, and the phase separation device is communicated with the water phase storage tank. In some embodiments of the application, the sodium removal system of spent caustic butter further comprises a pH monitoring device for monitoring the pH of the acetic acid solution in the acetic acid solution storage tank. In some embodiments of the application, the sodium removal system of spent caustic butter further comprises a first flow control valve and a second flow control valve, the acetic acid storage tank is in communicat