Freezing problem

QUENCH LIQUID SELECTION The choice of the appropriate quench liquid depends on a number of fac tors. Water is usually the first quench hquid to consider, since it is nontoxic, nonflammable, compatible with many effluent vapors, and has excellent thermal properties. If water is selected as the quench liquid, the tank should oe located indoors, if possible, to avoid freezing problems. If the tank has to be located outdoors in a cold climate, the addition of antifreeze is preferable to heat-tracing the tank, since overheating the tank can occur from tracing, thus reducing its effectiveness. 

Combinations of water and cold or autorefrigerating hydrocarbons which could result in freezing problems. 

Keywords borehole heat exchangers, freezing problem, principal solution... 

The examples below and Figure 59 shows how to avoid problem with freezing in borehole, but in particular what to do about the problem that already exists. In the principal drawings (Figures 60-67), which outlines different ways to solve freezing problems, the scales are incorrect. 

It is not possible to have freezing problem when the tubes are surrounded by air, so the lower level in the casing will minimize the risk of a freezing problem in the casing. This solution means that almost no heat will be extracted from the soil (through the casing) and that a deeper borehole in the rock is required. 

The studied freezing problem in borehole systems is rare, but it causes big problems for those individual who are affected. It is also a problem for the... 

So far there has not been any solution for this problem. In this study however, the problem is analyzed and explained. The risk increases with the soil depth, i.e., long casing. Some of the suggested principal solutions will solve the freezing problem by controlling, reducing or draining the pressure. 

In new systems when there is a high risk of freezing problems to occur some of the suggested measures should be used. 

London and Seban (L8) introduced the method of lumped parameters in melting-freezing problems, whereby the partial differential equation is converted into a difference-differential equation by differencing with respect to the space variable. The resulting system of ordinary differential... 

About one third of the heat produced by an engine is lost through the exhaust, another third to produce propulsion, and the last third is removed by the coolant. Water has the highest heat capacity, so less needs to be used. However, it freezes easily and corrodes engines quickly. Early antifreezes were salt brines. They reduced the freezing problem, but enhanced the corrosion problem. Methanol and ethanol then were used, but they boiled away too easily and were quite flammable. In 1927, Prestone was introduced, which was ethylene glycol (HO-CHjCHj.OH) mixed with anticorrosion additives. 

Attention to low-rate operation is the key to avoiding freezing problems. The following techniques can be used. 

The pipeline crossed the Rocky Mountains, so the elevation varied between a low point of 1676 m (5500 ft) and a high point of 2499 m (8200 ft). To minimize freezing problems, the pipeline was buried to a depth of 1,8 m (6 ft). There are 12 monitoring or testing points along the pipeline to monitor for pressure. If freezing or sedimentation develop, the resultant increase in pressure is automatically detected. 

Kroeger PG, Ostrach S (1974) The solution of a two-dimensional freezing problem including convection effects in the liquid region. Int J Heat Mass Transf 17 1191-1207... 

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