Cost of Shutdown

To maintain good relations with customers, get the products outsourced, i.e. manufactured on contract by supplying raw materials and paying conversion charges to another industry for manufacturing the products—strictly as per specifications. 

Cogeneration products such as power, steam, hot air, or hot water cannot be sold during the plant shutdown. 

Consumption of power, water, steam, etc., may stiU continue to prevent solidification of products and choking of pipelines or to maintain low temperatures in storages for volatile liquids, plant lighting, water supply, operation of effluent treatment facilities, etc. 

Costs incurred due to replacement of damaged parts/repairs to machinery by purchase of new spares. 

lubricants, and consumables for welding and gas cutting. Electrical, instmmentation spares and civil repair jobs (flooring, support beams and columns, and storm water drains lining). 

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In addition to environmental and safety factors, some of the early decline in manufacture was hastened by a series of plant shutdowns between 1971 and 1973 resulting primarily from the high costs of the acetylene-based process. No new production capacity is planned in the United States for the foreseeable future. 

For gas turbines, especially the more advanced high-temperature gas turbines, the oil of choice should be synthetic oil, since synthetic oils have a high flash point. Gas turbine lubrication systems should be run for about 20 minutes after shutdown since maximum temperatures are reached after 10 minutes of shutdown especially in the bearing area. Most gas turbines are also on turning gear to avoid sagging in the shaft. Mineral oils can be used for the compressor. It is not uncommon to have two types of oil in a petrochemical plant. Mineral oil costs much less than the synthetic oil. 

Several steps can be taken to maximize the run time for the reciprocating compressor. Since wear is a function of rubbing speed, the piston speed can be kept to a minimum. Chapter 3 made recommendations for piston speed. Reliability problems due to valves are reputed to account tor 40% of the maintenance cost of the compressor. Valves are the single largest cause for unplanned shutdowns. Basically, valve life can he increased by keeping the speed of the compressor as low as practical. At 360 rpm, the valves are operated six times a second. At 1,200 rpm, ihc valves operate 20 times a second or 1,728,000 times in a day. It is not difficult to understand why the valves are considered critical. To keep the reliability in mind, valve type, material selection and application considerations such as volume ratio, gas corrosiveness, and gas cleanliness need attention by the experts. One final note is that while lubrication is an asset to the rubbing parts, it is not necessarily good for valve reliability. 

The principal economic implications of corrosion of a plant are the initial cost of construction, the cost of maintenance and replacement, and the loss of production through unplanned shutdowns. The initial cost of the plant is influenced by material selection, and a choice of material that is more corrosion resistant than is necessary for the safe operation of the plant over its design life is a very expensive error. This cost involves initial outlay of money, and plants have been built which could never be profitable because of the inappropriate materials selection. 

Operators who balk at the cost of providing water treatment for resistance boilers are perhaps the very same people who fail to provide adequate maintenance from the beginning of their employment and end up complaining because of unplanned production shutdowns and considerable (and unnecessary) high-cost repairs. Water treatment does not have to be sophisticated or expensive for such relatively small and simple items of boiler equipment, but some form of treatment and control is required. 

Most waterside problems develop insidiously. Over time, scale and other types of deposit are gradually formed on internal heat transfer surfaces, which gradually raises the cost of providing heat energy. Some types of deposition can be very difficult and costly to remove. Corrosion wastes away the fabric of the plant (sometimes very quickly) and may produce an unexpected and untimely boiler plant shutdown, with a consequential loss of space heating, electricity, or process manufacturing capability. Likewise, fouling reduces the size of waterways and increases boiler operational problems. 

In 1997, an explosion occurred in a furnace of an oil distillation unit, resulting in a shutdown of the whole unit. The explosion occurred during a hot restart and resulted in a rupture of the entire furnace, which badly injured one operator. The total costs of damage was estimated to be 10,000,000 for loss of production and business interruption. 

If the operating cost during filtration is 10/ks and the cost of a shutdown is 100, what is the optimum filtration time for minimum cost ... 

Taking Cc as the cost of a shutdown and the variable cost during operation including a labour component as Cb, then the total cost during period tP is ... 

In a sold-out market, a DuPont intermediates process was operating at 56% of peak capacity. The major cause of the rate limitation was identified as poor decanter operation. The decanter recovered a valuable catalyst, and the poor operation was caused by fouling from catalyst solids. Returning the process to high utility required a 20-day shutdown. During the shutdown, the vessel was pumped out and cleaned by water washing. The solids and hydrolyzed catalyst were then drummed and incinerated. A waste stream analysis identified three cost factors the volume of wastewater that had to be treated, the cost of the lost catalyst, and the incineration cost. 

Research to reduce the liquefaction costs for hydrogen could potentially benefit its cost of shipment by truck, ship, or rail, but could also be advantageous for storage at plant sites to guard against unplanned shutdowns. The committee views this research as more appropriate for nearer-term investment, since this mode of shipment could dominate in the early stages of fuel cell vehicle introduction. 

In addition to the purchase price of catalysts, the refining operation has to be shut down for several days to replace the catalyst, which represents a lost revenue. Refiners always try to schedule catalyst replacements at the time of routine maintenance shutdowns. However, the need for catalyst replacement sometimes necessitates costly unscheduled shutdowns. An in-situ catalyst regeneration process not only can increase the life of the catalyst but also can alleviate the unscheduled shutdowns. 

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