Solution pipe

These systems are typically provided for the protection of atmospheric or low pressure storage tanks. They consist of one or more foam chambers installed on the shell of a tank just below the roof joint. A foam solution pipe is extended from the proportioning source, which is located in a safe location, to a foam aspirating mechanism just upstream of the foam chamber or pourer. A deflector is usually positioned on the inside tank wall at the foam chamber. It is used to deflect the foam against the tank wall and onto the surface of the tank or the tank and shell seal area. 

In a warm and semi-arid climate thick calcretes can develop. Alteration in the vadose zone is relatively rapid but not as rapid as in the phreatic zone. Surface karst is present locally, and caves are small and rare. The mineralogical changes follow the pattern of Figure 7.25, but at a rate slower than that for a warm, subtropical climate like Bermuda. Under the extreme of a warm, wet tropical climate, extensive terra-rossa soils can develop, and dissolution features, such as caves, solution pipes and fractures, should be prevalent. Mineralogical stabilization should occur rapidly. 

Solution is normally supplied to or removed from the solution circulation zone through solution pipe 53 attached to the top of heat exchanger 15. Solution can be more quickly removed from the system by an axial dump... 

Discontinuities are the fundamental factors governing the mass permeability of chalk. Chalk also is subject to dissolution along discontinuities. However, subterranean solution features generally tend not to develop in chalk since it is usually softer than limestone and, hence, so collapses as solution occurs. Nevertheless, solution pipes and swallow holes are present in chalk. 

The amount of water held in a soil or rock mass depends on its reservoir storage properties (see Chapter 4) that, in turn, influence the amount of water that can drain into a tunnel. Isolated heavy flows of water may occur in association with faults, solution pipes and cavities, abandoned mine workings or even pockets of gravel. Tunnels driven under lakes, rivers and other surface bodies of water may tap a considerable volume of flow. Flow also may take place from a perched water table to a tunnel beneath. 

It is readily observed that the pipe intersection standard can be useful in the design of solution pipe intersection systems. The review of the standard and its development efforts (past and present) provide an understanding of the standard effort, its dynamic character, and the opportunity for individuals to enhance the standard with constructive comments or suggestions. 

Recommended Maximum Amine Solution Piping Velocities for Rich and Lean Amine Solutions... 

The presence of these acids in crude oils and petroleum cuts causes problems for the refiner because they form stable emulsions with caustic solutions during desalting or in lubricating oil production very corrosive at high temperatures (350-400°C), they attack ordinary carbon steel, which necessitates the use of alloy piping materials. 

Concentrate each of the two solutions (or eluates) to about 20 ml, by distilling off the greater part of the benzene, the distilling-flask being immersed in the boiling water-bath. Then pour the concentrated solution into an evaporating-basin, and evaporate the remaining benzene (preferably in a fume-cupboard) in the absence of free flames, i.e., on an electrically heated water-bath, or on a steam-bath directly connected to a steam-pipe. Wash the dry residue from the first eluate with petrol and then dry it in a desiccator pure o-nitroaniline, m.p. 72°, is obtained. Wash the second residue similarly with a small quantity of benzene and dry pure />--nitroaniline, m.p. 148" , is obtained. Record the yield and m.p. of each component. 

Now, contrary to popular opinions, this method need not be conducted in a sealed pipe bomb. Secondary amination by substitution is as much a reaction of opportunity as it is of brute force and heat. In fact, heating can tend to cause the reformation of safrole and isosafrole. So the simplest way to do this would be to use 500mL of ammonium hydroxide or alcoholic ammonia or, for those wishing to make MDMA or meth, 40% aqueous methylamine or alcoholic methylamine (to tell you the truth, methylamine is preferable in this method because it is more reactive that ammonia so yield will increase). This 500mL is placed in a flask and into it is poured a solution of 35g bromosafrole (30g phenylisopropyl-bromide) mixed with 50mL methanol. The flask is stoppered and stirred at room temperature for anywhere from 3 to 7 days. The chemist could also reflux the same mixture for 6-12 hours or she could throw the whole mix into a sealed pipe bomb (see How to Make section) and cook it for 5 hours in a 120-130°C oil bath. 

METHOD 2 [89]--1M MDA or benzedrine and 1M benzaldehyde is dissolved in 95% ethanol (Everclear), stirred, the solvent removed by distillation then the oil vacuum distilled to give 95% yellow oil which is a Schiff base intermediate. 1M of this intermediate, plus 1M iodomethane, is sealed in a pipe bomb that s dumped in boiling water for 5 hours giving an orangy-red heavy oil. The oil is taken up in methanol, 1/8 its volume of dH20 is added and the solution refluxed for 30 minutes. Next, an equal volume of water is added and the whole solution boiled openly until no more odor of benzaldehyde is detected (smells like almond extract). The solution is acidified with acetic acid, washed with ether (discard ether), the MDMA or meth freebase liberated with NaOH and extracted with ether to afford a yield of 90% for meth and 65% for MDMA. That s not a bad conversion but what s with having to use benzaldehyde (a List chemical) Strike wonders if another aldehyde can substitute. 

All of this careful addition is to keep the reaction from starting before the bomb is sealed. It is also important to note that the chemist must scale up or scale down the amount of reactants so that the total amount of all the ingredients consumes no less than 90 of the volume space of her particular pipe bomb. Too much head space with its atmospheric air will lower the yield. The bomb is heated in an oil bath or oven at 105-115°C for 18-24 hours and the contents are then distilled with the 1,3 benzodioxole coming over at about 170-175°C with no vacuum, Alternatively, the chemist can only distill off the methanol, wash with dilute NaOH solution and extract with ether, etc. 

Steel is an acceptable material of constmction for handling solutions of up to 50% NaOH below 40°C. Above 40°C the steel corrosion rate increases rapidly and iron is picked up in the solution. Materials for handling 50% NaOH are lined steel for tank cars and lined or unlined steel for tanks and piping. 

Fig. 23. TVA pipe reactor system for production of 10—34—0 or 11-37-0 base solution from low conversion superphosphoric acid.

Filtration of viscose is not a straightforward chemical engineering process. The solution of cellulose xanthate contains some easy-to-deal-with undissolved pulp fibers, but also some gel-like material which is retarded rather than removed by the filters. The viscose is unstable and tends to form more gel as it ages. Its flow characteristics make the material close to the walls of any vessel or pipe move more slowly, get older, and gel more than the mainstream viscose. So while filtration can hold back gels arising from incomplete mixing, new gels can form in the pipework after the filters. 

---