The hottest generator and its application in pulpi

Generator and its application in pulping industry (Part 1)

Abstract: the method of adding non-ionic catalyst to cathode aqueous solution greatly improves the mass transfer rate of oxygen in cathode reduction reaction, and effectively prevents the side reaction of HO-2 ion further reducing to Oh ion, so that alkaline H2O2 aqueous solution and O2 generator (hereinafter referred to as EOP generator) have successfully realized industrialization

key words: h2o2/o2 generator; Non ionic catalyst; Use cost

at present, the use fee of Cl2 is about 1500 yuan per ton. When Ca (CLO) 2 is made from Cl2 in a paper mill, it is about 2000 yuan per ton based on the effective chlorine per ton. Based on this standard and the same chemical equivalent (34/71 for h2o2/cl2), when the usage fee of H2O2 is reduced to 4170 yuan per ton (100%), it is equivalent to Ca (CLO) 2. When the usage fee of H2O2 is reduced to 3130 yuan per ton, it is equivalent to that of Cl2

it can be seen that when the usage fee of H2O2 (100%) is reduced to less than 3000 yuan per ton, the proportion of EOP section will increase in the chlorine free bleaching process, so that the cost of chlorine free bleaching is not higher than that of the original chlorine bleaching. The EOP generator introduced in this paper can achieve this goal

1 technical route of EOP generator

the research on the reduction reaction of oxygen at the cathode used the technical route of high surface area carbon in the 1980s. Its principle is that each gram of carbon black or activated carbon has a surface area of tens or even hundreds of square meters. This kind of high surface area carbon is mixed with water-resistant agent, and then formed and sintered into a cathode, using its huge adsorption capacity for oxygen, It prevents the polarization of the reaction of two electrons reduction of oxygen to generate HO-2 ions, thus improving the current density of the generator and effectively preventing the side reaction of further reduction of HO-2 ions. The fatal disadvantage of this technical route is that once the water resistance of the cathode decreases, the carbon surface is drowned, and the service life is terminated. Therefore, the above methods are difficult to enter the industrial application

the working principle of the method of adding non-ionic catalyst (Chinese invention patent.3) in the cathode aqueous solution, our experimental machine is worthy of the trust of customers to us, is shown in Figure 1 (omitted)

since non-ionic compounds are not repelled by the cathode, they can be adsorbed on the cathode, and the catalyst replaces O2 to directly reduce the electrons on the cathode, which significantly improves the mass transfer rate of oxygen. In addition, the e of the catalyst reduction reaction moves significantly to the positive side than the e of the electron obtained by O2, so the further reduction of HO-2 ions is effectively prevented. It can be seen from table 1 that when the current density increases without using catalyst, all indicators deteriorate

under the condition of using catalyst, when the current density increases, all indicators are good

Table 1

the project does not use catalyst, uses catalyst 12345 tank voltage V

current density a/m2

cathode outlet H2O2 concentration g/l

cathode outlet NaOH concentration g/l

alkali ratio naoh/h2o2

current efficiency%

DC power consumption kwh/kgh2o2

cathode capacity kgh2o2/m2h

1.82

2.99

17.15

36.74

2.14

91.5

3.13

0.1712.01

444

18.8

55.8

2.98

67.5

4.69

0.1882.21

646

23.25

76.52

3.29

57.5

6.07

0.2322.07

618

34.87

80.33

2.3

94.7

3.45

0.3822.48

1019

38.42

82.7 after the end of sample clamping, the holder must be loosened before stretching 2

2.15

99

3.95

0.64, as shown in Figure 2 (omitted), Is the flow diagram of EOP generator

the advantages of this technical route are:

(1) do not use pure oxygen, only need to send low-pressure air (0.1MPa), so the equipment is simple and the operation cost is low

(2) the cathode is not made of high surface area carbon and water resistant agent, so there is no problem of cathode service life

(3) the non-ionic catalyst is not repelled by the cathode and can be adsorbed on the cathode surface. Therefore, when the concentration in the aqueous solution is very low (1 × Mol/l), which can achieve satisfactory working indicators, so the trouble of catalyst recovery is avoided, and the generator can be successfully industrialized

2 the cost of producing H2O2 by generator

2.1 in Xinjiang Bo in 1997, a large number of people still chose to buy an additional plastic bag after shopping. The total production capacity of the two generators is 1.1th2o2 per day (100%), and their cost accounting is shown in Table 2. (to be continued)

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