WET
END
Technologies
3
(11)
1. Circulating loops of PM Approach / short circulation process 上浆系统循环回路/短循环工艺
If the dosage location has a long distance to the headbox, it generates some significant disadvantages:
The long delay time keeps the chemical extended time together with stock components, it meets randomly
disturbing colloidal material, entrained gas bubbles and liquids/additives circulating or injected into the
process with different pH, temperature, concentration and chemical composition. Reactions may be partly
meaningful with targeted results, but partly reactions are generated randomly, uncontrolled and by accident
resulting to unwanted outcome.
如果计量点离流浆箱距离远将产生重大缺陷：长的延时时间导致化学品在浆料化合物中滞留遇上无序混合的胶
体材料，产生气泡和液体循环或以不同的 PH 值、温度、浓度、以及化学品消耗量注入工艺过程，反应效果可
能只是预期效果的一部分，这仅有的一部分也只是意外产生的无序的失控的并不期望的结果。
Several circulating loops of the PM short circulation process will keep part of chemicals in circulation longer
periods thus extending the time with above, explained effect. The figure 2 shows the circulating loops and first
pass percentage of additive flows to the slice.
由于上述滞留造成化学品在上浆系统的各个回路都有一定的滞留。图 2 单程通过在各个回路的通过百分率。
If additive is added into the mixing chest, approx. only 50% of the flow has straight access as a first pass flow
to headbox and as much as 50% of the flow begins to re-circulate in loops. The long delay time with
circulations slows down and makes it more difficult to make production adjustments. The extended delay time,
multiple re-circulations of partial flows makes the whole process complex: Chemical reactions and the wet end
surface chemistry is difficult to predict and follow - specially in situations when the process is not well
balanced. System cleanliness also can be widely reduced due to these facts. The process can generate
deposits in uncontrolled situations.
如果添加剂在混合浆池加入单程通过量只有 50%或者说只有 50%的添加剂直接到达了流浆箱，其余 50%的添
加剂在系统中循环，延时时间越长系统生产调节越困难，延时时间加倍了再循环药品的量使工艺系统系统成分
复杂化，使得湿部化学品反应平衡越来越难以预料，难以控制，难以追踪。特别是在系统平衡还没有完全达到
时，这种无序状态会产生大量失控垃圾，使系统的清洁度回大大降低。
Slow blending versus fast and effective mixing of additives 添加剂的缓慢混合与快速混合比较
If mixing of reactive additive into a complex process media is made with a fast and effective manner, outcome
is a reaction or reactions with the correct manner and with targeted end result. Reaction is e.g.: R + K
Æ AB
Only small number of side effects may come up.
如果添加剂以快速高效的风格混合到一个复杂的系统中，反应的结论是混合的风格正确结果可达到预期效果例
如：R + K
Æ AB
If mixing is made slowly and with a random interaction and concentrations, result is that the injected additive
will meet varying conditions on its way forward in the process. There can be several different reactions
如果混合是在缓慢并且伴随有无序交感作用以及浓度，结论是注射的添加剂在其在工艺系统的进程中遇到了各
种不同的条件产生了多种可能的效果:
R + H
Æ YV
R + K
Æ AB
R + YV
Æ LKJ
YV + AB
Æ ED
Extended time and random additive concentrations bring possibilities for additional unwanted side reactions.
The background and problems can be summarized as follows 延时时间和无序浓度带来了一些有害的边缘反应:
-dosage points of additives vary from mixing chest to headbox feed pipe
- 添加剂的计量点从混合池到流浆箱喂料管之间变化
-circulating loops distribute additives across the process with large variation of time delay
-
循环回路中化学添加剂的分配随时间延时变化大
-addition points are located early in the process to “guarantee” decent mixing
-
增加早期加入点以“保证”完全混合
-additives have a long delay in the process before sheet formation
-
添加剂在纸页成型之前已在工艺过程中长时间滞留
-long response times in dosing adjustments and control
-
在计量以及控制调整后响应时间长
-strong beliefs exist about “right” dosage locations 坚信现有的就是“”正确的”
-complex
chemistry
化学品复杂化