Papermaking wastewater mainly comes from the pulping and papermaking processes in the papermaking industry.
Pulping is to separate the fiber from the plant raw materials into a slurry, and then bleach it.
Papermaking is to dilute, shape, squeeze, and dry the slurry to make paper.
Both processes discharge large amounts of waste water. Wastewater from pulping is the most polluted.
The wastewater discharged from pulp washing is dark brown, called black water. The concentration of pollutants in the black water is very high, the BOD is as high as 5-40g/L, and it contains a lot of fibers, inorganic salts and pigments.
The wastewater discharged from the bleaching process also contains a large amount of acid and alkali substances.
The waste water discharged from the paper machine is called white water, which contains a large amount of fiber and fillers and rubber materials added in the production process.
The treatment of wastewater from the papermaking industry focuses on increasing the recycling rate, reducing water consumption and wastewater discharge, and actively exploring various reliable, economical and capable of fully utilizing the useful resources in wastewater treatment methods.
The flotation method can recover fibrous solids in white water, the recovery rate can reach 95%, and the clarified water can be reused.
The combustion method can recover sodium hydroxide, sodium sulfide, sodium sulfate and other sodium salts combined with organic matter in black water. The neutralization method adjusts the pH value of wastewater.
Coagulation sedimentation or flotation method can remove suspended solids in wastewater.
Chemical precipitation method can decolorize; biological treatment method can remove BOD, which is more effective for kraft paper wastewater.
The wet oxidation process is more successful in treating sulfite pulp wastewater. There are also treatment methods such as reverse osmosis, ultrafiltration, and electrodialysis.
A large-scale paper industry sewage treatment project in Guangdong: The system mainly treats the discharged sewage from the papermaking production line, with a cooling system designed to handle 60000m³/d. The heat exchange method is adopted to exchange heat and reduce the temperature of the sewage, so that the temperature of the effluent reaches the target of ≤37°C.
In response to this working condition, Jiema has fully considered the working environment of the project in the selection of heat exchange equipment, and has taken anti-corrosion and anti-rust measures. The use of a special plate heat exchanger effectively solves the purpose of heat exchange and cooling of sewage and improves the recycling rate of sewage.
Jiema’s products are widely used in all aspects of papermaking industry:
|Heat exchanger used in pulping process||Heat exchanger type|
|Exhaust condenser of wood storehouse||Shell&tube heat exchanger|
|Cold spray cooler||Shell&tube heat exchanger|
|Cooking circulation heater||Shell&tube heat exchanger|
|Cooking steam saving device||Shell&tube heat exchanger|
|Black liquid cooler||Shell&tube heat exchanger|
|Hot water heater||Shell&tube heat exchanger|
|Oxygen defiltrate cooler||Shell&tube heat exchanger|
|Oxygen defiltrate condenser||Shell&tube heat exchanger|
|PO defiltrate heater||Shell&tube heat exchanger|
|Alkaline waste water cooler||Shell&tube heat exchanger|
|Demineralized water heater||Shell&tube heat exchanger|
|Pulp machine fresh air heater||Finned tube heat exchanger|
|Cadre damaged paper blower heater||Finned tube heat exchanger|
|Heat exchanger used in alkali recovery process|
|Evaporative intercondenser||Shell&tube heat exchanger|
|Condenser tube after evaporation||Shell&tube heat exchanger|
|Spare ethylene glycol steam preheater for gasifier||Shell&tube heat exchanger|
|Stripper adjusting condenser||Shell&tube heat exchanger|
|Top condenser of stripper||Shell&tube heat exchanger|
|Methanol condenser||Shell&tube heat exchanger|
|Top condenser of methanol tower||Shell&tube heat exchanger|
|Alkali furnace water refill & condensate heat exchanger||Shell&tube heat exchanger|
|Dilute white liquid cooler||Shell&tube heat exchanger|
|Causticizing dilute odor condenser||Shell&tube heat exchanger|
|Gasifier air preheater||Finned tube heat exchanger|
|Odor DNGG preheater||Finned tube heat exchanger|
|Evaporating heavy pollution condensate heat exchanger||Plate heat exchanger|
|Evaporating high-concentration odor heat exchanger||Plate heat exchanger|
|Causticizing sewage condensate heat exchanger||Plate heat exchanger|
|Demineralized water heat exchanger for gasifier power plant||Plate heat exchanger|
Post time: Sep-22-2020