Annual shutdown

Scheduling of work tasks and therefore labor utilization can be carried out in a number of different methods on a computer, depending on the software system purchased. These methods can be similar to the manual system or they may take the form of automatic scheduling. That is, the work tasks are entered into the computer system with the appropriate hours and trades and the software program automatically schedules the hours evenly over the weeks of the year. In implementing such scheduling care has to be taken to ensure that such items as weekends, statutory holidays, annual leave, annual shutdown and seasonal... 

Figure 1 - The Effective Working Time, Amount of Roasted Concentrate, Sulfuric Acid Production, Concentrate Grain Size and Amount of Leached Concentrate in the Kokkola Plant. (Note the annual shutdown is included in the effective working time.)...

Regular replacement of the tubes every 2 years and pressure tests during annual shutdowns will be found useful. 

Regular replacement of the tubes every 2 years, provision of stainless steel AISI-316 ferrules at the gas entries of the tubes, and pressure tests during annual shutdowns will be found useful. 

Earlier designs used a circular shape for the submerged coils. It was difficult to take out these coils for maintenance or for complete cleaning of the pit during annual shutdowns due to the settled sludge. 

It may be noted that the hot gas filters not only minimized deposition of dust particles in the catalyst beds but also increased the heat capacity of the conversion system. In the case of a long plant stoppage, there could be more heat retention in the plant when blinds are inserted in the gas inlet line of the HGF. The unit would also protect the top layer of the first pass catalyst from any soot/unbumt carbon particles during plant start-up (during commissioning or after an annual shutdown.)... 

After annual shutdown same as above but generally is done over a shorter period of 36-48 h. 

Contract personnel for issue of sulfur, water treatment, general housekeeping, and for annual shutdown jobs. 

Annual shutdown costs (for cleaning of sulfur pits, catalyst replacement, acid tower cleaning, etc.) depend on the run and the problems faced by the plant during the year and the need for replacement of any eqnipment. 

Arrangement for creating a whirling (rotating) zone of burning sulfur spray. Arrangement for removal of ash deposits during annual shutdown. 

Activity analysis, vanadium pentoxide contents, and attrition loss reports from catalyst mannfactnrer regarding the samples taken out during annual shutdown... 

The profit per MT and return on investment shall be estimated on these figures. It is obvious that all efforts shall be made to minimise the annual shutdown period and other stoppages during the year. 

Case Study An Annual Shutdown of a Sulphuric Add-Oleum Plant... 

It is noticed many times that the production rate slowly reduces as the annual shutdown approaches due to building up of scales and dust in boilers, heat exchangers, and catalyst passes and deposits on the demisters in the acid towers. This can cause increased pressure drop in the process units, and the air blower has to deliver against considerably more total back pressure. Plant operators may have to reduce the airflow to the plant in such situation. 

Alternative arrangement made to dispatch by carboys or by direct pumping to nearby customers or the production rates may be curtailed if nothing is possible. Any pending maintenance job may be taken up or annual shutdown may be advanced if possible. 

Any pending major maintenance job may be taken up or annual shutdown may... 

The plant should not cause any enviromnental pollution. Waste generation shall be minimum during start, normal running, and also during annual shutdown of the plant. There should be in-built effluent treatment facilities to treat all effluents. 

TAPS-l was under annual shutdown from July 1996 to mid January 1997 for mandatory regulatory inspection of core shroud and other systems. 

TAPS-2 started generation from June 1996 after annual shutdown from September 1995 to May... 

MAPS-1 started generation from September 1996, after annual shutdown from April 1995 to August... 

Even in factories where planned maintenance is not officially applied the first method of breakdown maintenance is rarely followed completely. When a given item of equipment has failed several times in the same way or after similar intervals of time, someone is sure to suggest that some preventative action should be taken before the time that the next failure is due. This may be as simple as saying that a particular pump, gearbox, or motor is overhauled in the annual shutdown because it is known from past experience that it will not last for another year . 

Partial core refuelling takes place annually, and the nuclear barge contains the refuelling facilities and fuel storage pond. Any major maintenance is also scheduled for the annual shutdown. 

Annual operating hours required—this depends on maximum time permitted for annual shutdown and stoppages during the year for various maintenance jobs. Generally 90% availability should be assured. The evaporation capacity should be specified accordingly on per hour and per annum basis. 

The packing items are generally washed thoroughly before placing in the towers for the first time or during an annual shutdown. 

Assume that in a company s annual shutdown for retooling and maintenance, a task is to be performed for which the likelihood of occurrence of a hazardous event was rated as Even chance could happen and the outcome would be Fatalities. In the illustration in Table 19, the ratings are purposely kept the same for likelihood of occurrence, frequency of exposure, and degree of possible harm. Ratings vary only for the number of people exposed. 

When the issue is looked at closely, then it may be noted that it is very difficult to test to detect the valve health. Full 100% travel, it can only be done during annual shutdown. From FMEDA tests results, shown in clause number 1.4.1 of Chapter Vlll, it is seen that higher the proof test interval higher will be PFD value, meaning that when such testing interval is high then it will have direct nearly linear impact on SIL value which is directly related to PFD value. 

Your assignment is to provide recommendations as to how much immediate scale-down is possible and what, if any, modifications would be needed to scale down by 50%. For now, you are to consider only the portion of the process prior to the switch condensers. You should also recommend any other changes that you feel should be made to inprove performance in Unit 700. Because our plant is due for annual shutdown in a few months, we want specific recommendations as to what should be done at that time and the cost of these alterations and/or modifications. 

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