Study On Cooling Water Stability And Resourcization Of Waste Water In Pelletizing Plant

Focusing on the characteristics of water quality of circulating cooling water and wastewater in a pellet plant, base on 《The standard for industrial circulating cooling water treatment design》(GB 50050-2007) and the industrial wasterwater reuse standard.Through the experimental study, put forward the circulation cooling water corrosion and scale inhibitor, biocide parameters of circulating cooling water and industrial wastewater treatment process, used in practical engineering.The average annual corrosion rate of circulating water is 0.0907 mm, the average annual corrosion rate is 0.1095 mm. Composite corrosion and scale inhibitor(HEDP: acid or sulfonic acid groups: zinc salt=3:3:1),dosage of 10mg/L,the inhibition rate can reach more than 70%.After 4 times of the circulating water concentration, the composite corrosite and scale inhibitor was added to 80mg/L, the inhibition rate was 82.2%, the average annual corrosion rate was 0.0473 mm, the corrosion rate was less than 0.075mm/a, meet the requiremants.The thermal resistance of the circulating water fouling is 4 2 19.9 10 m K W--? ? ?. Composite corrosion and scale inhibitor has good scale inhibition effect, dosage of 10mg/L, the annual fouling thermal resistance reached less than 4 2 11.4(10 m K W)--? ? After 4 times of the circulating water concentration, the composite corrosion and scale inhibitor dosage of 60mg/L, the annual fouling thermal resistance is achieved 4 2 13.04(10 m K W)--? ?,less than 4 2 13.44 10 m K W--? ? ?, reached the expected target.Isothiazolone and organic guanidine bactericide efficiency is high, at the dosage of 30mg/L, the sterilization rate is more than 99%, algae removal rate is 97.5%, the number of heterotrophic bacteria less than 51?10 / m L,reached the target requirments.And the performance of the composite corrosion and scale inhibitor is also demonstrated.On the basis of the experiment put forward the project of the water quality stability method, when the concentration factor is 4 times, the composite corrosion and scale inhibitor is 80mg/L, the treatment cost is 0.022 yuan/m3.Annual savings 600000m3,significant economic benefits.For the pre-grinding wastewater, the best coagulant is PAC, the best dosage is 15mg/L; The best optimal coagulant is PAM, the best dosage is 0.5mg/L. Designing the pre-gringding waster water treatment method, the scale of the water for scheme one is 4800m3/d, the scheme two is 2400m3/d. The total investment for scheme one is 2200000 yuan, running costs 0.3284 yuan/ton. The total investment for scheme two is 1580000 yuan, running costs 0.3804 yuan/ton.This project solved the environmental problems caused by the circulation cooling water and pre-grinding wasterwater, and promote the sustainable development of enterprises.The annual water saving 1000000 m3, has good environmental benefit, social benefit and economic benefit.