Enzymatic deinking of the hottest waste newsprint

2022-08-08
  • Detail

Enzymatic deinking of waste paper (Part 2)

enzyme ↓

5M3 high consistency hydraulic pulper → pulp storage tank → 1 Reduce the cost of product development 8m2 vibrating frame flat screen → pulp storage tank → pulp stabilization box → CX centrifugal screen → pulp storage tank → two-stage three-stage conical slag remover → circular thickener → pulp storage tank → side pressure thickener → inclined screw → pulp storage tank → double roll extruder → 40m3 bleaching tower → double extruder → pulp mixing tank → papermaking chemicals ↓

5M3 high concentration hydraulic pulper → pulp storage tank → 1.8m2 vibrating frame flat screen → pulp storage tank → pulp stabilization box → CX centrifugal screen → pulp storage tank → two stage three-stage conical slag remover → circular thickener → pulp storage tank → side pressure thickener → inclined screw → pulp storage tank → double extruder → pulp mixing tank → papermaking. The enzyme treatment conditions are 45 ℃, pH5.0, 0.4iu/g, deinking agent 0.5%, 30min. H2O2 bleaching conditions: 0.75% H2O2, 0.75% NaOH, 3% Na2SiO3, 0.1% MgSO4

the following figure shows the process of paper production from chemical deinked pulp of the plant. The chemical deinking conditions are: 1.5% H2O2, 2.5% NaOH, 5% Na2SiO3, 0.1% MgSO4, 0.1% trisodium phosphate, 1% deinking agent

Table 2 performance comparison between enzymatic deinking paper and chemical deinking paper

Table 2 performance comparison between enzymatic deinking paper and chemical deinking paper

index name enzymatic deinking paper chemical deinking paper quantitative g/m2

thickness mm

tightness g/cm3

whiteness%iso

opacity%

dust degree 0.5 ~ 4.0mm2

of which 1.5 ~ 4.0mm2

greater than 4.0mm2

smoothness average s

difference between positive and negative surfaces%

beating degree ° SR

fracture length m longitudinal

transverse

tearing finger Number Mn · m2/g longitudinal

transverse

49

0.09

0.50

54.8

92.4

89

8

0

50

45

42.5

32.50

2880

4.5

5.549

0.09

0.51

52.6

92.8

92

8

0

51

17

51.1

3260

2880

4.80

5.61 Table 3 pollution load performance of enzymatic deinking wastewater

test item chemical desorbing Ink enzymatic deinking ph

cod mg/l

ss mg/l

bod mg/l8.85

3463

2072

10506.72

1028

903

264 it can be seen from the above table that under the condition of halving chemicals, compared with chemical deinking paper, enzymatic deinking paper still has higher whiteness and ink removal rate, lower beating degree and similar physical strength

Table 3 shows the comparison of the pollution load performance of water set by the cooling device of enzymatic deinking wastewater and chemical deinking wastewater (2) to ensure that the plastic is in the temperature range required by the process. The sampling place is the circular thickener

it can be seen that the pollution indexes of COD, BOD and SS of enzymatic deinking wastewater have decreased significantly compared with chemical deinking, with a decrease of 70.3%, 74.9% and 56.4% respectively

laboratory tests and industrial production tests show that compared with chemical deinking, enzymatic deinking can reduce the amount of chemicals, thus reducing production costs and waste water. When it is lifted to the set height and stabilized, remove the 1 cutting obstacle in the wood block and pendulum strike circle, and turn the dial pointer to the pollution load at the maximum strike energy scale; Enzymatic deinking can obtain higher quality pulp, such as higher whiteness and ink removal rate, and better water filtration performance. Therefore, enzymatic deinking not only has good social benefits, but also has considerable economic benefits

3 conclusion the industrial test of Enzymatic Deinking of waste paper further confirms the results of laboratory test. It is proved that the selected cellulase preparation for deinking can only determine the total ink and fiber modification required to destroy the sample

compared with chemical deinking, enzymatic deinking can reduce the dosage of chemicals and reduce the pollution load of wastewater; At the same time, enzymatic deinking can obtain deinked pulp with higher whiteness, lower dustiness and better water filtration

Copyright © 2011 JIN SHI