Damage column

This can lead to nonlinearity, peak broadening, tailing, and even a damaged column. Check the method. 

Caustic or acid must be removed as thoroughly as possible from the system prior to the commencement of a water wash otherwise, a violent reaction may occur and damage column internals. 

Finally, as described in section Loss of Vertical Carrying Capacity, axial failure of a shear-damaged column can occur by sliding along an inclined crack plane, with resistance provided by... 

Elwood K, Moehle JP (2005b) Axial capacity model for shear-damaged columns. ACI Struct J 106(S45) 578-587... 

When fluid flows past objects or through orifices or similar restrictions, vortices may periodically be shed downstream. Objects such as smokestacks, chemical-processing columns, suspended pipehnes, and electrical transmission lines can be sul ected to damaging vibrations and forces due to the vortices, especially if the shedding frequency is close to a natural vibration frequency of the objecl. The shedding can also produce sound. See Krzywoblocki (Appl. Mech. Rev., 6, 39 397 [1953]) and Marris (J. Basic Eng., 86, 185-196 [1964]). 

Effects. Trays can become damaged several ways. A pressure surge can cause damage. A slug of water entering a heavy hydrocarbon fractionator will produce copious amounts of vapor. The author is aware of one example where all the trays were blown out of a crude distillation column. If the bottom liquid level is allowed to reach the reboiler outlet line, the wave action can damage some bottom trays. 

Whatever the cause of the tray damage, however, it is often hard to prove tray damage without column shutdown and inspection, especially if damage is slight. Besides poorer fractionation, a damaged tray section will experience a decrease in temperature difference because of the... 

Here, we refer to small amounts of water rather than large slugs that could damage the trays. Often the water will boil overhead and be drawn off in the overhead accumulator bootleg (water drawoff pot). However, if the column top temperature is too low, the water is prevented from coming overhead. This plus too hot a bottom temperature for water to remain a liquid will trap and accumulate water within the column. The water can often make the tower appear to be in flood. 

Tube and shell heat exchangers, small distillation columns, reactors, valves, pumps and other items are available in impregnated grapliite. Graphite can be joined only by cementing, which embrittles on aging. It is prone to mechanical damage, particularly when subjected to tensile stresses. 

While drain valves are installed to get rid of unwanted liquid, vent lines get rid of unwanted gas or vapor. They should be located so that the vapor is unlikely to ignite, so that damage is minimal if it does ignite, and so that people are not affected by the gas or vapor discharged. One fire destroyed a small plant. It started because the vent on a distillation column condenser discharged into the control room, possibly to prevent pollution of the surroundings, which had given rise to complaints about the smell [1] (see Section 2.11.3). 

Water can be trapped behind heat exchanger baffles and then suddenly vaporized by circulation of hot oil. It can also be trapped in dead-ends and U-bends in pipework (see Section 9.1.1). Such U-bends can form when one end of a horizontal pipe is raised by thermal expansion. The trays in a distillation column were damaged during startup when hot gas met water, from previous steaming, dripping down the column [3J. Section 17.12 describes an incident somewhat similar to a foamover. 

Do not connect the column to the detector. This precaution will prevent any contaminants precipitating in the flow cell that could damage it. 

Note that if Ko values are above 1, there must be a nonspecific interaction between the target molecule and the matrix. In the case of Ko values below 0, the column packing is probably damaged. 

There are different reasons to discard a column a column can be damaged by irreversible adsorption of reactive polymer samples. Small amounts of styrene oligomers are known to permanently elute from styrene-divinylbenzene materials with tetrahydrofuran as the eluent, which means a continuous shear degradation of the separation material and consequently a decrease of the packing quality this observation is very important if fractions are collected and used for further analyses, e.g., for the determination of infrared (IR) spectra. One can presume that similar effects are present with other organic materials too. 

---