CN112978825A

CN112978825A - Method for treating high-concentration sewage generated in waste oil regeneration process

Info

Publication number: CN112978825A
Application number: CN202011573539.8A
Authority: CN
Inventors: 王洪雷; 郭钢福
Original assignee: Hubei Dajiang Runye Renewable Resources Co ltd
Current assignee: Hubei Dajiang Runye Renewable Resources Co ltd
Priority date: 2020-12-25
Filing date: 2020-12-25
Publication date: 2021-06-18

Abstract

The invention provides a method for treating high-concentration sewage generated in the conventional waste oil regeneration process, which is characterized in that high-concentration sewage generated in the regeneration oil distillation link with extremely large CoD (more than 20 ten thousand) Bod5/Cod being too low (less than 0.3) is subjected to steam stripping evaporation and MVR low-energy consumption evaporation to dryness, oil in the sewage is collected, the CoD of the sewage is greatly reduced to be less than 10000, and Bod5/Cod is more than 0.6, so that the sewage is converted into easily-treated common sewage, and the sewage is treated by a conventional sewage treatment system and then reaches the standard to be discharged.

Description

Method for treating high-concentration sewage generated in waste oil regeneration process

Technical Field

The invention belongs to the technical field of petrochemical industry, and relates to a harmless treatment method of high-concentration sewage generated in a waste oil regeneration process.

Background

All factories in the current waste oil regeneration field can not avoid raw oil flash evaporation dehydration and distillation gas injection process. The link can produce high-concentration sewage with extremely high Cod (20-40W) Bod5/Cod less than 0.3, difficult biochemical treatment and serious odor (sulfur compounds such as mercaptan, thioether and the like).

More than 90% of renewable oil enterprises cannot effectively treat the sewage due to insufficient cognition and lack of research and development capacity of the sewage, and finally only can dilute the drainage network by using a large amount of clear water, so that the sewage treatment capacity and treatment difficulty of the park are increased.

Disclosure of Invention

The technical scheme of the patent of the invention is as follows: because the high-concentration sewage contains a large amount of organic matters (including gas micromolecules causing bad smell sense), the technical scheme adopts the process of evaporation and stripping, oil materials at the bottom of the evaporation tower account for about 1.5-3% of the total mass of the sewage, the non-condensable gas at the top of the tower is mostly micromolecule mercaptan, thioether and other peculiar smell gases, and the gas is introduced into a waste gas main pipe through a wind pipe to enter an incinerator for harmless incineration. The evaporated condensed water basically does not contain organic matters, Bod5/Cod is improved by nearly 3 times, the original sewage which is difficult to biochemically process and has the BC ratio of less than 0.3 is changed into the sewage which is easy to biochemically process and has the BC ratio of 0.8, and other special treatments and dilution are not needed, so that the evaporated condensed water and other sewage of a factory can be normally treated in a sewage plant.

The invention provides a brand-new acid sludge treatment method, which comprises the following steps:

firstly, evaporating, refluxing and stripping;

secondly, performing oil-water separation by using an MVR low-energy-consumption evaporation technology;

and thirdly, treating the water phase.

In the first step, the sewage to be treated is heated and evaporated, the gas flow speed is accelerated by injecting nitrogen at the bottom, and the tower top is cooled and refluxed. So that the organic volatile matter is separated from the water and introduced into the gas pipeline to the incinerator for harmless incineration.

And the second step is further specifically that the water phase separated from the organic volatile matter in the first step is subjected to MVR evaporation, the evaporated bottom accounts for about 1-3% of the total weight of the fuel oil phase, the fuel oil phase is recycled and used as a blending raw material or used as a waste oil raw material for tempering, and the evaporated water phase CoD is less than 10000 and Bod5/CoD is greater than 0.6.

The third step is further conventional biochemical treatment of water phase, and the standard discharge is simply achieved through aerobic, anoxic, anaerobic and other biological treatment links and conventional water treatment methods such as air-float aeration, carbon filtration and the like.

Advantageous technical effects

The high-concentration sewage treatment method can reduce the CoD value of the high-concentration sewage most effectively, improve Bod5/CoD, extract oil in the high-concentration sewage, further realize economic value and avoid environmental pollution.

Drawings

FIG. 1 is a process flow diagram of treatment of high concentration sewage generated in the regeneration of waste oil

Detailed Description

The invention provides a brand-new high-concentration sewage treatment method, which comprises the steps of firstly introducing high-concentration sewage which is difficult to be biochemically treated and has COD higher than 20 ten thousand and Bod5/COD less than 0.3 into an evaporation stripping tank, increasing the flow rate of steam by heating and injecting nitrogen, and cooling and refluxing the top. And after full stripping for 1h, pumping the bottom aqueous phase to an MVR evaporator, evaporating water, collecting oil, cooling water vapor, collecting the cooled water vapor to a low-concentration sewage tank, detecting that the CoD is less than 10000 and the B/C is greater than 0.6, and pumping the aqueous phase from the low-concentration sewage tank to a conventional sewage treatment plant matched with a factory for treatment.

All of the above mentioned intellectual property rights are not intended to be restrictive to other forms of implementing the new and/or new products. Those skilled in the art will take advantage of this important information, and the foregoing will be modified to achieve similar performance. However, all modifications or alterations are based on the new products of the invention and belong to the reserved rights.

The foregoing is directed to preferred embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. However, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the protection scope of the technical solution of the present invention.

Claims

1. A method for treating high-concentration sewage generated in a waste oil regeneration process comprises the following steps:

firstly, evaporating, refluxing and stripping;

and thirdly, treating the water phase.

2. The method for treating high-concentration sewage generated in the waste oil reclamation process as recited in claim 1, wherein the sewage to be treated is heated and evaporated in the first step, the gas flow rate is accelerated by injecting nitrogen gas into the bottom, and the reflux is cooled at the top of the tower, so that the organic volatile matter is separated from water and is introduced into a gas pipeline to the incinerator for harmless incineration.

3. The method for treating high-concentration sewage generated in the waste oil regeneration process according to claim 1 or 2, wherein the second step is further characterized in that the water phase separated from the organic volatile matter in the first step is subjected to MVR evaporation, the evaporated bottom accounts for about 1-3% of the total weight of the fuel oil phase, the fuel oil phase is recycled and used as a blending raw material or used for waste oil recycling, and the evaporated water phase CoD is less than 10000 and Bod5/CoD is greater than 0.6.

4. The method for treating high concentration sewage generated in the waste oil reclamation process as recited in claim 3, wherein the third step is further a conventional biochemical treatment of water phase, and the standard discharge is simply achieved by biological treatment links such as aerobic, anoxic and anaerobic treatment, and conventional water treatment methods such as air-float aeration and carbon filtration.