電解車(chē)壓差控制-中英對(duì)照
電解車(chē)間壓差控制

通常，電解車(chē)間中的壓差總體的控制，是通過(guò)對(duì)共同電解車(chē)間排出管上游氯氣和氫冷卻的工作壓強(qiáng)和差壓的測(cè)量來(lái)進(jìn)行。對(duì)一個(gè)有下游氯氣和

干燥管的電解車(chē)間來(lái)說(shuō)，最簡(jiǎn)單人們最會(huì)傾向于采取的控制策略包括將氯作為主工作壓強(qiáng)控制器，同時(shí)通過(guò)一個(gè)壓差控制器將氫排出到大氣中

，以此同時(shí)來(lái)控制氫壓強(qiáng)。

電解車(chē)間壓差控制器內(nèi)的設(shè)定值必須時(shí)刻保持在氫大于氯15mbar，控制系統(tǒng)應(yīng)起調(diào)節(jié)作用，這樣在穩(wěn)態(tài)運(yùn)行狀態(tài)下，壓差的波動(dòng)相對(duì)于設(shè)定值

不會(huì)超過(guò)正負(fù)3mbar。但是，必須避免離子膜震顫的發(fā)生，由于控制系統(tǒng)過(guò)于敏感， 它會(huì)引起離子膜和網(wǎng)眼之間的摩擦損害。

對(duì)于偏差和脫扣運(yùn)行來(lái)說(shuō)，測(cè)量到的差數(shù)波動(dòng)性增大是可以允許的，壓差控制系統(tǒng)必須設(shè)計(jì)成在所有可能的分離帶來(lái)的干擾下，比如整流器脫

扣，壓差不會(huì)超過(guò)氫大于氯-10到+40mbar的范圍，一旦超出這個(gè)范圍，無(wú)論超出時(shí)間多段，都會(huì)對(duì)離子膜和電解組件造成不可修復(fù)的損害。

至關(guān)重要的一點(diǎn)是，要充分考慮到壓差測(cè)量設(shè)備的可靠程度和系統(tǒng)中建立冗余的潛在需求。

4.6.2局部電解壓差控制

對(duì)于裝載超過(guò)一個(gè)BICHLORTM 電解槽的電解車(chē)間來(lái)說(shuō)，關(guān)鍵是壓強(qiáng)和差壓控制器要在一臺(tái)BICHLORTM 電解槽和另一臺(tái)BICHLORTM 電解槽的開(kāi)車(chē)

和停車(chē)要分開(kāi)�？刂破鳡I(yíng)控制電解槽局部支流的排出，當(dāng)通往主總管的氣體隔離閥關(guān)閉后，通過(guò)極化并凈化氣體形成氯吸收（氯氣）和大氣排

放（氫氣）。

局部壓差控制器的設(shè)定值必須在氫大于氯10-15mbar之間，控制系統(tǒng)應(yīng)起調(diào)節(jié)作用，在穩(wěn)定開(kāi)車(chē)或停車(chē)狀態(tài)下，壓差的波動(dòng)相對(duì)于設(shè)定值不會(huì)超

過(guò)正負(fù)3mbar�？刂葡到y(tǒng)應(yīng)設(shè)計(jì)為，當(dāng)開(kāi)車(chē)和停車(chē)運(yùn)行時(shí)，在所有可能的瞬間突發(fā)狀況發(fā)生時(shí)，壓差不會(huì)超過(guò)氫大于氯0到+30mbar的范圍。

系統(tǒng)大小須滿(mǎn)足開(kāi)車(chē)和停車(chē)時(shí)所有無(wú)用雜料的凈化要求，同時(shí)適用于極化階段產(chǎn)生氣體。盡管如此，若在一臺(tái)電解槽的開(kāi)車(chē)和停車(chē)階段，需要

防止凈化氣體進(jìn)入主總管，那么可能需要調(diào)整系統(tǒng)尺寸，滿(mǎn)足等值于1千安/m2。同時(shí)系統(tǒng)必須可調(diào)試，這樣壓強(qiáng)就能順利地在大氣壓強(qiáng)和電解

車(chē)間運(yùn)作壓強(qiáng)之間提高或降低，并使得壓差一直處于上述定義的控制區(qū)間內(nèi)。
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