Control of bacteria and bacterial sludge in the pr

Control of bacteria and bacterial sludge in the production of high-speed paper machine (II)

in order to grasp the system status in a timely and accurate manner and achieve the best sterilization effect (1) it is convenient to adjust the impact position, we take the following control measures for the above sterilization scheme:

(1) take samples from the thick pulp system, thin pulp system, clean water and white water system, coating, starch and other additive systems every week for bacterial culture, and display the test data in charts, If the test results are found to deviate from the control range, immediately take treatment measures. (2) Make the test chart of the whole system every quarter to evaluate the efficiency of the existing sterilization scheme. 2.2 in the process of adding fungicides and preservatives

in view of the closed cycle characteristics of our 4550mm paper machine, it is determined that DuPont industrial bioscience company ultimately shows a more cost-effective process of adding fungicides and preservatives:

(1) pulp, paper damage, white water system

(2) clean water system

(3) coating and auxiliary material system

removes bacteria from clean water, Chlorination treatment can be added at the inlet and outlet of raw water clarification equipment, which has been proved to be maintained (3 ×）%～ （5 ×）% (0.3 ~ 0.5ppm) residual chlorine can achieve the best effect

generally, the damaged paper system can be added at the inlet of the damaged pulp tank to increase its reaction time; The paint can be added into the paint mixing tank; Starch and other chemical additives are generally added in the storage tank

2.3 in the dosage and effect analysis of fungicides and preservatives

for the above formulation of the addition process of fungicides, we adjust their dosage respectively, and then take samples to cultivate bacteria, test the sterilization results. See Table 2 for the dosage adjustment and sterilization results of several main parts

it can be seen from table 2 that the bacteria in the system decrease sharply after the use of fungicide. With the increase of the dosage of fungicide, the number of bacteria in the headbox further decreases. However, when the dosage of fungicide reaches the best effect, further increasing its dosage will no longer significantly improve the sterilization effect, and will lead to an increase in cost. Therefore, after starting the bactericide system, the system must be tested to ensure the best sterilization effect at the lowest cost

in addition, with the change of the external natural environment, the paper machine system has been significantly affected, and the breeding rate of bacteria and bacterial sludge in the system has also changed significantly. For example, the bacterial detection in the clean water system and the white water system in several months of 1999 is shown in Figure 1 and Figure 2

Fig. 1 Comparison of bacterial content in clean water system in different months

Fig. 2 Comparison of bacterial content in white water system in different months

therefore, it is necessary to regularly track and detect the sterilization of the system, and it can produce products of more than 2000 brands in three categories in the field of modified high molecular materials, which can be adjusted with the changes of the environment. (to be continued)