{"id":11943,"date":"2021-12-17T02:45:30","date_gmt":"2021-12-17T02:45:30","guid":{"rendered":"https:\/\/www.newater.com\/?p=11943"},"modified":"2024-03-13T03:45:20","modified_gmt":"2024-03-13T03:45:20","slug":"oil-refining-and-petrochemical-wastewater-treatment","status":"publish","type":"post","link":"https:\/\/www.newater.com\/oil-refining-and-petrochemical-wastewater-treatment\/","title":{"rendered":"Wastewater Treatment for Oil Refining and Petrochemical"},"content":{"rendered":"

1. Background.<\/span><\/h3>\n

The rapid development of the petrochemical industry has brought huge economic effects, but also produced a large number of petrochemical industrial wastewater. At present, there are nearly 500 billion cubic meters of petrochemical industrial wastewater in the world every year, polluting 5.5 trillion cubic meters of fresh water, which is equivalent to more than 14% of the total global runoff. Therefore, for sustainable development, petrochemical industry wastewater needs to be treated before discharge.<\/p>\n

Importantly, advanced treatment and recycling of petrochemical industrial wastewater is also an important measure for water conservation and emission reduction. The wastewater treatment<\/a> of petrochemical enterprises is still one of the difficult problems at home and abroad. It is urgent to solve the technology of treatment of high salt and oil-bearing wastewater and reuse of reclaimed water. As an experienced wastewater treatment company, NEWater is always practicing the concept of sustainable development.<\/p>\n

2. Sources and Characteristics of Refinery and Petrochemical Wastewater.<\/span><\/h3>\n

The main sources of refinery and petrochemical wastewater are petrochemical industrial wastewater and refinery circulating cooling water. It has a wide variety, complex composition, high toxicity, inhibition of biodegradation, and high concentration. The specific characteristics are as follows:<\/p>\n

(1) The water quantity is large, and the water quality is complex and changes greatly.<\/p>\n

The production scale of the petrochemical industry tends to be large-scale, because there is a large amount of sewage treated in the whole plant, and the sewage discharged every day is 10000 tons. Petrochemical enterprises need to add various solvents, additives, and additives in the production process, and then go through various reactions. Therefore, the composition of wastewater is quite complex.<\/p>\n

(2) Serious organic pollution.<\/p>\n

The organic matter contained in petrochemical wastewater is mainly hydrocarbons and their derivatives. The high concentration of waste liquid discharged from some petrochemical units is still high after incineration or other appropriate treatment.<\/p>\n

(3) Sewage contains heavy metals.<\/p>\n

Because many reactions in petrochemical production are completed under the action of catalysts, dozens of catalysts are used in a large petrochemical plant, so the wastewater often contains heavy metals.<\/p>\n

NEWater has developed ultrafiltration<\/a> and reverse osmosis<\/a> combined processes and equipment for wastewater treatment in two application scenarios: petrochemical industrial wastewater and refinery circulating cooling water, which can help enterprises greatly reduce the total amount of wastewater discharge, and save the consumption of primary water, reduce production costs and improve economic and environmental benefits.<\/p>\n

3. Oil Refining and Petrochemical Wastewater Treatment Plant Application Scenarios.<\/h3>\n

3.1 Wastewater Treatment Process in Petrochemical Industry.<\/h3>\n

At present, wastewater reuse technology<\/a> has been popularized in iron and steel, petrochemical, and electric power industries, but the wastewater from the petrochemical industry has high COD concentration, complex residual oil composition, and a large change in water quality. Affected by water quality and the production treatment process, the characteristics of membrane pollution of the same type of petrochemical wastewater at different times and places will be very different. The petrochemical wastewater reuse unit developed by NEWater uses the tertiary treated wastewater of the first purification unit as the water source, adopts the combined process of ultrafiltration and RO, and the product water is used as the make-up water for the petrochemical industry.<\/p>\n

\"Figure2

Ultrafiltration is to separate pollutants through mechanical screening. Ultrafiltration membrane<\/a> elements have the characteristics of selective separation. Under pressure, suspended solids, large organic particles, and oil slicks contained in wastewater are intercepted outside the ultrafiltration membrane, while small water molecules and salts from water production are through the ultrafiltration membrane. A submerged ultrafiltration membrane module is adopted for ultrafiltration of the Jingyi unit, and the design recovery rate of each set is not less than 90%.<\/p>\n

\"Figure3

RO membrane technology<\/a> is a very mature technology for preparing ultrapure water in recent years. The main mechanism is that the same volume of dilute solution and concentrated solution are placed on both sides of the semi-permeable membrane. Due to the concentration difference, the dilute solution penetrates the concentrated solution side. This process is called infiltration. When the permeation reaches equilibrium, the liquid level of the concentrated solution is a certain height higher than that of the dilute solution, thus forming a pressure difference, which is called osmotic pressure.<\/p>\n

The osmotic pressure depends on the properties of the liquid, such as type, concentration, and temperature, and has nothing to do with the properties of the semi-permeable membrane. If a pressure greater than the osmotic pressure is artificially applied on one side of the concentrated solution at this time, the penetration direction of the solvent will be opposite to the original direction, that is, it will flow from the concentrated solution side to the dilute solution side. This phenomenon is called reverse osmosis.<\/p>\n

\"Figure4

The anti-pollution composite reverse osmosis membrane module is adopted for the reverse osmosis of the first purification unit<\/a>, and the stable desalination rate is 98%. A double membrane process, namely ultrafiltration, and reverse osmosis system<\/a> are adopted.<\/p>\n

The reuse process of petrochemical wastewater is as follows: Discharged Petrochemical Wastewater up to Standard \u2192 Bactericide \u2192 Homogenization Regulation of Regulating Tank \u2192 Self-Cleaning Filter<\/a> \u2192 Ultrafiltration Membrane Tank \u2192 Suction of Ultrafiltration Water Production<\/a> Pump \u2192 Ultrafiltration Water Production \u2192 Ultrafiltration Water Production Tank \u2192 Scale Inhibitor\/Effluent Reductant\/Non-Oxidizing Bactericide\u2192 Reverse Osmosis System \u2192 High-Pressure Pump<\/a> \u2192 Output Qualified Water \u2192 Water Tank \u2192 External Supply as Water for Petrochemical Industry.<\/p>\n

Although some petrochemical wastewater can meet the discharge standard, it will still pollute the environment. After the proper treatment, NEWater can be used as water for the petrochemical industry, which can not only reduce environmental pollution but also realize recycling and truly turn waste into treasure. The combined process of ultrafiltration and reverse osmosis can well remove various petrochemical pollutants. The wastewater treated by this process can meet the water standard of the petrochemical industry.<\/p>\n

3.2 Refinery Circulating Cooling Water Treatment.<\/h3>\n

During the use of circulating cooling water in the refinery, through the exchange of heat and mass transfer of cooling structures, the drainage is polluted to a certain extent due to the leakage of pollutants in the air such as soil, sundries, soluble gas, and heat exchanger materials during the open operation of circulating cooling water.<\/p>\n

\"Figure5

The drainage of the circulating cooling water system has the following characteristics:<\/p>\n