电解车压差控制-中英对照
电解车间压差控制
通常，电解车间中的压差总体的控制，是通过对共同电解车间排出管上游氯气和氢冷却的工作压强和差压的测量来进行。对一个有下游氯气和
干燥管的电解车间来说，最简单人们最会倾向于采取的控制策略包括将氯作为主工作压强控制器，同时通过一个压差控制器将氢排出到大气中
，以此同时来控制氢压强。
电解车间压差控制器内的设定值必须时刻保持在氢大于氯15mbar，控制系统应起调节作用，这样在稳态运行状态下，压差的波动相对于设定值
不会超过正负3mbar。但是，必须避免离子膜震颤的发生，由于控制系统过于敏感， 它会引起离子膜和网眼之间的摩擦损害。
对于偏差和脱扣运行来说，测量到的差数波动性增大是可以允许的，压差控制系统必须设计成在所有可能的分离带来的干扰下，比如整流器脱
扣，压差不会超过氢大于氯-10到+40mbar的范围，一旦超出这个范围，无论超出时间多段，都会对离子膜和电解组件造成不可修复的损害。
至关重要的一点是，要充分考虑到压差测量设备的可靠程度和系统中建立冗余的潜在需求。
4.6.2局部电解压差控制
对于装载超过一个BICHLORTM 电解槽的电解车间来说，关键是压强和差压控制器要在一台BICHLORTM 电解槽和另一台BICHLORTM 电解槽的开车
和停车要分开。控制器营控制电解槽局部支流的排出，当通往主总管的气体隔离阀关闭后，通过极化并净化气体形成氯吸收（氯气）和大气排
放（氢气）。
局部压差控制器的设定值必须在氢大于氯10-15mbar之间，控制系统应起调节作用，在稳定开车或停车状态下，压差的波动相对于设定值不会超
过正负3mbar。控制系统应设计为，当开车和停车运行时，在所有可能的瞬间突发状况发生时，压差不会超过氢大于氯0到+30mbar的范围。
系统大小须满足开车和停车时所有无用杂料的净化要求，同时适用于极化阶段产生气体。尽管如此，若在一台电解槽的开车和停车阶段，需要
防止净化气体进入主总管，那么可能需要调整系统尺寸，满足等值于1千安/m2。同时系统必须可调试，这样压强就能顺利地在大气压强和电解
车间运作压强之间提高或降低，并使得压差一直处于上述定义的控制区间内。
4.6 Differential Pressure Control
4.6.1 Cellroom Differential Pressure Control
Differential pressure is normally controlled on the cellroom as a whole from measurements of working pressure and differential pressure at the common cellroom outlet headers upstream of chlorine and hydrogen cooling. For a typical cellroom with downstream chlorine cooling and drying train, the simplest preferred control scheme involves using chlorine as the master working pressure controller with hydrogen pressure following this via a differential pressure controller that vents hydrogen to atmosphere.
The cellroom differential pressure controller must operate at all times with a set point of 15 mbars hydrogen over chlorine. The control systems should be tuned, such that under steady state operating conditions, the fluctuation in differential pressure around the set point does not exceed +/- 3 mbar.
However, what must be avoided is membrane ‘flutter’ due to an oversensitive control system, which can cause abrasive damage of membranes against the meshes.
For operating excursions, trips etc greater fluctuations in measured differential are permissible. The differential pressure control system must be designed such that under all conceivable operating excursions from disturbances such as rectifier trips, the differential pressure never goes outside the range of –10 to + 40 mbars hydrogen over chlorine. Any departure from this range, however short in duration, could result in irreversible damage to membrane and Electrolyser components.
It is essential that full consideration is given to the reliability of differential pressure measurement instruments and the potential requirement for building redundancy into this system.
4.6.2 Local Electrolyser Differential Pressure Control
For cellrooms containing more than one BICHLORTM Electrolyser, it is essential that pressure and differential pressure controllers are provided to permit start-up and shutdown of an Electrolyser independently from other Electrolysers in the cellroom. The controllers will control local sidestream vents from the Electrolyser, which will pass polarisation and purge gases into chlorine absorption (for chlorine) and atmosphere (for hydrogen), when the isolation valves to the main gas headers are closed.
The set point for the local differential pressure controllers must be 10-15 mbars hydrogen over chlorine. The control systems should be tuned, such that under steady start-up / shutdown conditions, the fluctuation in differential pressure around the set point does not exceed +/- 3 mbar. The control system must be designed such that under all conceivable transient events during start-up and shut-down operations, differential pressure never goes outside the range of 0 to + 30 mbars, hydrogen over chlorine.
These systems must be sized for full inerts purge requirements at start-up and shutdown, and for gases generated during polarisation. However, it may be necessary to size them for process gas flows up to the equivalent of 1 kA/m2 if there is a requirement to prevent purge gases entering the main gas headers during start-up and shut-down of a single electrolyser. They must also be set-up so that pressure can be smoothly raised and lowered between atmospheric and cellroom operating pressure, with differential pressure always within the control envelope defined above.
2014.8.22