Pump, glycol

For ethylene glycol systems copper tubing is often used (up to 3 in), while pumps, cooler tubes, or coils are made of iron, steel, brass, copper, or aluminum. Galvanized tubes should not be used in ethylene glycol systems because of reac tion of the inhibitor with the zinc. Methanol water solutions are compatible with most materials but in sufficient concentration will badly corrode aluminum. 

Many manufacturers will estimate maximum glycol losses to be 1 lb or. 1 gal per MMscf. Improper operation can increase the actual glycol losses to 1, 10, or even 100 gallons per MMscf. One leaking pump can waste 35 gallons per day (Ballard, 1977). 

Rich glycol is leaking into lean glycol in the glycol heat exchanger or in the glycol pump... 

Glycol powered pump. Close the dry discharge valve and see if the pump continues to run if so, the pump needs to be repaired. 

Gas or electric driven pump. Verify adequate circulation by shutting off the glycol discharge from the absorber and timing the fill rate in the gauge glass. 

If a glycol pump has been operating in a clean system, no major service will probably be needed for several years. Only a yearly replacement of packing is usually required. Normally the pump will not stop pumping unless some internal part has been bent, worn, or broken. 

A pump which has been running without glycol for some time should be checked before returning to normal service. The pump will probably need at least new O rings. The cylinders and piston rods may also have been scored from the dry run. ... 

The pump will start and run until the glycol returns from the absorber. The pump then stops or slows appreciably and will not run at its rated speed. 

Pump stops and leaks excessive gas from the wet glycol discharge. 

Traps in the wet glycol power piping send alternate slugs of glycol and gas to the pump. 

Insufficient glycol to the Main Piston D-slide ports. Elevate the control valve end of the pump to correct. 

Maintenance and production records, along with the used lean and rich glycol analyses, can be very helpful to the troubleshooter. A history of filter element, carbon, tower packing, and firetube changeouts can sometimes be very revealing. The frequency of pump repairs and chemical cleaning jobs is also beneficial. With this type of knowledge, the troubleshooter can quickly eliminate and prevent costly problems. 

Most glycol dehydration processes are continuous. That is, gas and glycol flow continuously through a vessel (the contactor" or absorber ) where they come in contact and the glycol absorbs the water. The glycol flows from the contactor to a reboiler (sometimes called "reconcentrator or regenerator where the water is removed or stripped from the glycol and is then pumped back to the contactor to complete the cycle. 

The gas from the glycol/condensate separator can be used for fuel gas. In many small field gas packaged units this gas is routed directly to fire tubes in the reboiler, and provides the heat for reconcentrating the glycol. This se[>.irator is sometimes referred to as a gas/glycol separator or pump gas separator. 

The process flow schematic in Figure 8-6 shows electric motor driven glycol pumps. On smaller systems it is common to use glycol powered pumps. These pumps use the energy contained in the rich (wet) glycol to... 

Figure 8 19. Glycol powered pump—piston moving to left. (Source Kimroy, Inc.]...

Glycol powered pumps are inexpensive and easy to repair in the field. They have many moving parts and because of their slamming reciprocating motion require constant attention. One spare pump should always be installed. 

Forced coolant systems using a mixture of glycol and water are the most common for natural gas compressors. Normally, the compressor cylinder cooling system and compressor frame lube oil cooling system is combined. A single pump is used to circulate the coolant through the cylinders and the lube oil heat exchanger and then to an aerial cooler where the heat is dissipated. 

Figures 13.25-13.28 show the ultrahigh resolution separations in chloroform of polystyrene standards, polytetramethylene glycol, urethanes and isocyanates, and epoxy resins, respectively. Multiple column sets of anywhere from two to six columns in series have been used for well over a year with no apparent loss of efficiency. The 500- and 10 -A gels can easily tolerate 15,000 psi or more. In fact, the limiting factor in the number of columns that can be used in series is generally the pump or injector in the FIPLC system. A pump capable of 10,000 psi operation should allow the use of a column bank of 10-12 50-cm columns with a total plate count of 500,000 or more.

GPSLLK Glycol pump seal leaks undetected... 

PW circulation pumps B/A mechanical failure PW circulation pumps B/A stopped by operator PW collecting tanks pmnps B/A failure PW flow switch failure PW supply pumps B/A controller 2 failure PW supply pumps B/A mechanical failure PW supply pumps B/A stopped by operator PW surge tank instrument failure -15 C glycol storage tank leak PW level valve fails... 

In Section 21.4 tlie effects of the release of toxic vapors were considered in connection witli an accident sequence initiated by the failure of a plant programmable automatic controller. In tliis study, event tree analysis and fault tree analysis led to identification of tlie glycol cooling system circulation pumps as components meriting high priority for inspection. 

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