Startup lines

A dump (or startup) line connecting col-lunn bottom sump and rdwiler liquid line should not be overlooked for once-throu reboilers. 

Pressurization (startup of feedwater pump) Start of nuclear heating Turbine startup Line switching Power raising ... 

The results of over 1 year of continuous, on-line acoustic emission (AE) structural surveillance of high temperature / high pressure steam headers, gained on 2 M-scale 600MW supercritical multifuel ENEL power units in normal operation, are presented in the paper. The influence of background noise, the correlation between plant operating conditions (steady load, load variations, startup / shutdown transients) and AE activity and the diagnostic evaluation of recorded AE events are also discussed. 

Most sulfonation plants monitor and control operations by computer. Sulfur-buming catalytic SO -generating equipment may require a 1—2 h stabilization period on startup. The unit can be kept in a standby position by maintaining heat to the unit when it is off-line. Liquid SO -based sulfonation plants do not require such a stabilization period and hence are more flexible to operate than sulfur-buming sulfonation plants. 

Mass storage device. Typically, fixed-head hard disk drives are used to store ac tive data, including on-line and historical databases and non-memory-resident programs. Memory-resident programs are stored to allow loading at system startups. The tape drives are used for archives and backups. 

The annual rate of straight-line depreciation of the fixed-capital investment Cfc, from 1,000,000 at startup to a salvage value S, of zero at the end of a productive life s of 10 years, is given hy... 

Heat build up Design discharge to avoid bridging, provide reli-due to plugged able instrumentation to detect full receiver (load discharge line. cells or level probe) Check lines to ensure they are clear before startup Monitor and alarm temperature CCPS G-f2 CCPS G-23 CCPS G-29 CCPS G-39... 

Column Bottom Temperature. The bottom temperature is often controlled on the reboiler outlet line with a control valve in the heating medium line. The control point can also be on a bottom section tray. Care must be exercised in location of the temperature control point. It is recommended, especially for large columns, that a cascade arrangement be used. The recommended scheme has a complete flow recorder/controller (FRC) in the heating medium line including orifice and control valve. The set point of this FRC is manipulated by the temperature recorder/controller (TRC). This eliminates the TRC from manipulating the control valve directly (recall that temperature is the most difficult parameter to control). This makes for smoother control for normal operations. Also, it is handy for startup to be able to uncouple the TRC and run the reboiler on FRC for a period. 

It is easy to improperly design a steam trap. The design must work for two circumstances and often a designer will check only one of these. The circumstance often overlooked is as follows On startup or upset the steam control valve can open wide so that the steam chest (assume for this discussion that we are speaking of a reboiler) pressure rises to full steam line pressure. At a... 

Flashback protection is required for H2S flaring systems, either by water seal or continuous gas purge. If a water seal is used, special requirements apply to the disposal of the effluent seal water. In the case of an HjS flaring system handling a flow of HjS which in uninterrupted throughout the period that a plant is in operation, and which stops only when the producing plant is shutdown, then flashback protection is not required. However, steam or inert gas connections are required to permit purging the flare line startup and shutdown. 

The line diagrams had been kept up-to-date despite the pressures on the plant staff during startup. This made it easier to repeat the relief and blowdown review. The plant staff members were so impressed by the results that they decided to have another look at the relief and blowdown after another year. 

Wholesale replaeement of such materials in existing plants is impractical, and there is no universal solution. Some lines can be replaced in different grades of steel. Sometimes low temperature trips or alarms can be used. Sometimes the need to watch the temperature closely during startup has to be impressed on operators. 

Most state laws and safe practice require a safety relief valve ahead of the first stop valve in every positive displacement compressed air system. It is set to release at 1.25 times the normal discharge pressure of the compressor or at the maximum working pressure of the system, whichever is lower. The relief valve piping system sometimes includes a manual vent valve and/or a bypass valve to the suction to facilitate startup and shutdown operations. Quick line sizing equations are (1) line connection, (i/1.75 (2) bypass, ii/4.5 (3) vent, dl63 and (4) relief valve port, cU9. 

Mechanical seals are often chosen and designed to operate with environmental controls. If this is the case, check the seal assembly drawing or equipment drawing to ensure that all environmental control piping is properly installed. Before equipment startup, all cooling and heating lines should be operating and remain so for at least a short period after equipment shutdown. 

Face lubricated-type seals must be connected from the source of lubrication to the tap openings in the seal gland before startup. This is another predetermined environmental control feature that is mandatory for proper seal function. Where double seals are to be operated, it is necessary that the lubrication feed lines be connected to the proper ports for both circulatory or dead-end systems before equipment startup. This is very important because all types of double seals depend on the controlled pressure and flow of the sealing fluid to function properly. Even before the shaft is rotated, the sealing liquid pressure must exceed the product pressure opposing the seal. Be sure a vapor trap does not prevent the lubricant from reaching the seal face promptly. 

In addition to the product, the designer, equipment installer, user, and all others involved in production should all consider performing a risk assessment and target in the direction of perfection. The production is reviewed for hazards created by each part of the line when operating as well as when equipment fails to perform or complete its task. This action includes startups and shutdowns, preventative maintenance, QC/inspection, repair, etc. 

Gas pressure must be properly regulated, all lines purged before use, and ignitors proven to work before initial startup. Also, all gas burning equipment must be regularly inspected for leaks to avoid risks of an explosion. 

One of the first operations in the startup phase is the flushing of all lines using air or water. Its purpose is to remove any foreign material that may have gotten into the lines. This includes welding rods, nails, plastic lunch bags, handkerchiefs, and the like. To do this, the water should flow at a velocity exceeding 12 ft/sec (3.6 m/sec) and the air at a velocity above 200 ft/sec (60 m/sec). 

Startup following maintenance produced process upset in reactor, water found in process materials, reflux line blocked resulted in overheating in reactor. 

On Friday, February 19, a 1.5-inch feed line to the heater column was replaced with a 2-inch line, which delayed startup until later in the morning. The concentration of liquid solution in the charge tank at that time was about 57% hydroxylamine. It steadily increased throughout the day. Between 7 00 and 7 15 p.m., the concentration of liquid solution in the charge tank was recorded as 86% hydroxylamine. 

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