Normal Cell Room Operation

While the data gave little reason for concern over the exposure of the general population to the field in a chlor-alkali plant, it is possible for the field to interfere with the operation of low-power electronic devices. Cardiac pacemakers are one example. The ACGIH in the same list of TLVs referred to above suggested a value of 5 G for persons with these devices. Adams reported that one company had set its own limit of 1G. Since this is a small multiple of the normal background, the rule effectively bars those with pacemakers from approaching a cell room. While not covered specifically by these rules, there should also be special concern for those who wear or carry other medical devices such as aneurysm clips, suture staples, and prostheses. These can respond to forces produced by stronger fields, but no definite limits have been set. 

The suction pressure controller, rather than the flow controller normally controls the recycle valve. However, if the compressor flow decreases to a critical point, the flow controller will take over operation of the valve and increase the flow to prevent surge. This will increase the suction pressure and in some cases can raise the cell room header pressure to the point where the seal pot opens. This would also occur if the compressor were allowed to go into surge. 

The most important considerations determining the normal operating philosophy and procedures adopted for the cell room include ... 

The brine system should be fully operational, on recycle and bypassing saturation and the electrolyzers, at a rate equivalent to that required for operation at 2-3 kA m. The brine temperature should be about 50°C at the cell room. Concentration should be as specified for normal operation (typically 300 gpl), and quality should meet all specifications. Analytical routines for the brine system should be in full operation by this time. 

General. Normal operating and monitoring routines for the individual electrolyzers, the cell room, and the associated plant are to be established and followed carefully. Process parameters should remain within the specified ranges. When upsets occur or an important parameter moves out of specification, the appropriate actions, which may include shutdown of the plant, must be taken. 

Brine and caustic should continue to flow through the electrolyzers at rates at least equivalent to those required for 3 kA m operation for some time after loss of current. This keeps the electrolyzers full on both sides and flushes free chlorine from the anolyte. Flushing should last at least 30 min or until the free chlorine content of the brine leaving the cells is below 1 gpl. Appropriate measures also should be taken to prevent reverse flow of chlorine from any part of the system into the electrolyzers. If circulation continues after flushing, the brine and caustic flows should be approximately those required for operation at 2 kA m . Monitoring of cell room parameters should continue at normal frequencies. 

A plant performance test will normally be carried out over a defined period (usually 48 hr or longer) during which the cell room will be operated steadily near the design load. To enable this, it must be established before the test that all peripheral systems are capable of steady operation at the required throughput. 

The normal range of acceptable operating temperature is 80-90°C. In a new cell room with new membranes of similar performance, it is possible to maintain temperatures on individual cells and electrolyzers within a tight band, and a typical target exit temperature would be 87°C. In an established cell room, the acceptable range provides adequate flexibility to accommodate membranes of different ages with different voltage performance. 

Typical cell rooms are shown in Figures 42 (bipolar cells) and 43 (monopolar cells). A cell in normal operation requires little attention. The critical requirement is that the brine flow rate is sufficient to maintain an anolyte level above the cathode. 

After acquiring a minimal amount of specimen, ranging from a few hundred to a few million cells, current proteomic analyses are able to generate MS patterns in a relatively short time span. In one study, less than 2 hours was needed to process human breast tissue that had been removed from the patient in the operating room until the MS data had been acquired. Mammary tissue containing normal breast epithelium and invasive carcinoma was compared, and over 40 peaks were identified that significantly differed in intensity [54]. This study employed LCM to acquire the tissue specimens. 

Concentrated H2SO4 solution is supplied in tank trucks and is transferred into storage tanks close to the formation room. The concentrated H2SO4 solution (1.84 rel.dens.) has to be diluted before being used for battery formation. Formation of batteries/cells is conducted in diluted electrolyte of e.g. 1.10 rel. den. At the end of the formation process, before the batteries are dispatched for sale, this electrolyte is replaced by a more concentrated H2SO4 solution of 1.28 rel. den., which is the electrolyte concentration for normal battery operation. 

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