The wastewater from chemical refining mainly consists of oily wastewater and alkaline wastewater. The water is alkaline with a pH of 7.5-8.0 and an oil content of 100-200 mg/L. Conducting research on the treatment of refinery wastewater into oil fields and water injection, using existing facilities for simple pretreatment within the refinery according to technical requirements, and then transporting it to the oil field sewage station for mixed treatment with produced water before injecting it underground, will have both economic and social benefits.

oil refiningWastewater treatment equipmentThe mechanism and characteristics of refinery wastewater generation:

Refinery wastewater mainly comes from the production wastewater generated during the direct distillation of crude oil, cracking and distillation of heavy oil, and refining of certain fractions. Generally, wastewater is classified and diverted based on its quality, including free oily wastewater, emulsified oil wastewater, cooling water, boiler drainage, sulfur-containing wastewater, alkaline wastewater, acidic wastewater, and some special compound wastewater. Its characteristics are reflected in:

The amount of sewage is large, the composition of wastewater is complex, the content of organic matter, especially hydrocarbons and their derivatives, is high, and it contains various heavy metals. In addition to general organic matter, the main pollutants include oil, phenols, sulfides, and ammonia nitrogen. Their COD content is high, and there are many difficult to degrade substances. Moreover, the pH of the wastewater varies greatly due to the influence of alkaline residue wastewater and acid washing water. Tiny oil droplets with a particle size between 100 and 1000 nm are easily surrounded by surfactants and hydrophobic solids, forming emulsified oil that is stably suspended in water. This state of oil cannot be separated from wastewater by static methods. Floating oil larger than 100 μ m in suspension can be separated from water by relying on the relative density difference between oil and water. After oil pollutants are discharged into water bodies, a molecular film is formed, which pollutes the water quality, reduces the dissolved oxygen (DO) content in the water, and generates CO2, forming H2CO3, causing a decrease in pH value and an increase in turbidity.

Chemical refining wastewater treatment equipment process:

Using an air flotation device to remove oil from oily wastewater and obtain a first oil phase and a first water phase; Dehydrate the first oil phase in a centrifuge to obtain a second oil phase and a second water phase, and recycle the second oil phase; The first aqueous phase enters the sand filtration device for fixed bed deep filtration. The solid particles and suspended solids in the first aqueous phase accumulate in the upper layer of the sand filtration device to form solid matter, and the filtered aqueous phase is collected and uniformly treated; Drying the solid matter and sand on the upper layer of the sand filtration device in a belt manner, where the hot air flow is combined with the transportation of the solid matter and sand to form granular solid matter; The granular solids and sand enter the cyclone separator simultaneously with the hot air flow for separation, and the granular solids are collected for unified treatment. The present invention achieves the separation of water, oil, and solid waste in wastewater, with a simple process that reduces the cost and energy consumption of wastewater treatment.