Thanks all of you.
The shell of exchanger was made of A537.
We had chemical cleaning in folloing procedure,
1.Isolated the exchanger and drain out the residuals.
2.Clean the exchanger with water.
3.Operated the soda circulation in 60?, and the solution pH value was control at 12. This...
I have tried injecting steam into the drain located on inlet of chemical cleaning and hoped it caused water hammer which can loosen the deposites. But it did not
work, even the drain was damaged by the vibraton.
Thank you for help.
In fact, it is an all welded unit. There are only two nozzels,12 inches and 14 inches, for the shell side and could not remove the tube at all.
Could sandblasting be applied in such case?
I have no idea about to burn out the deposits. Is it easy and safe to...
Does anyone have the experiences of cleaning spiral wound heat exchanger? Especially the exchangers are operated in Rectisol Unit.
The feed gas is 65% H2, 33% CO2, 0.5% H2S and contained traces of soot and heavy metal. This feed gas entered the shell side of the exchanger and a part of the...
The differential pressure between sour gas and lube oil in a H2 expander remains a low value. It causes the spare lube oil pump start several times a day. When I decrease the sour gas pressure, the lube oil pressure located in upstream of bearing also become lower. I just want to increase the...
Dear IRstuff
Thank you for the information.
In my case, we have redundant PLC System that means it has two Digital Output Card to deal with the signal. But the problem locates outside the system, in case the fuse, the srecw on terminal or damaging on the cable were failure. This loop will out of...
Dear Vinzzzz,
I have read an article said the octagonal ring joint flange is suitable for oval and octagnoal ring.
But oval ring joing flang is only for oval type ring.
I am not sure it is corrcet.
Because my plant only has octagnoal type flange, we use both oval and octagnoal ring. until now...
yes, it could be a solution. In fact there is a backup pump standby. But there is no automaticly startup design.
Add a dealy off timer in the interlock. Before the trip signal activated, the spare pump must startup automaically.
How about the wiring loop?
Does anything we can do?
Thanks!
Some of our critical loops which could cause the whole plant to stop are designed with single loop. It means we can not allow any failure in this loop.
For example, an interlock of level switch causes to stop pump that will activate the other interlock and stop plant. We have a 2oo3 design for...
Hi Milutin,
There are three different feeds to the stripper.
The top one temperature rich co2 methanol is -58 DegC,the the middle one temperature riched H2S methanol is no indicator and the bottom one temperature lean co2 methanol is -30 DegC.
The top and bottom feed in upper section stripper...
The stripper bottom temperature decreased when the methanol spilled out. It is an endothermic reaction as the methanol contained CO2 flush into the stripper.
If there is a flooding in the stripper that it should accumulate more methanol in tower. Since the inlet flow rate is fixed and then the...
In fact, I had no ideas in which upset to cause the downcmoer problem. In two years ago, there was an upset in this stripper when started up the oter unit. An operator opened 1",50kg/cm2 valve connected to stripping N2 line too much.
There are no NaOH and water upstream of stripper. Why did...
Dear Milutin,
You definitely have good experiences on the column operation. The situation was exactly what you mentioned. One more problem is such flooding occurred in the lower section column will cause the liquid methanol blow out throuth the demister?
Why does it only occurred two times in...
This stripper has 89 valve trays divided into two sections.
The overhead temperature is -58 degC and bottom temperature is -23 degC. From my experience on cleaning the stripper,the internal of the stripper is very clean. what reasons will cause fouling at such operated variable?
There has...
Dear all,
we have the CO2 Stripper which stripes the CO2 from the Methanol by N2.
Recently its differential pressure is increasing gradually from 0.35 to 0.45 Kg/cm2 in past 2 months. Sometimes as the differential pressure increased quickly and reached 0.5 Kg/cm2, the methanol will spill out in...
There are three expansion control valves in the bottom of H2 stripper in the cold box.
The normal process conditions are following:
1. Stripper operates at 18 kg/cm2.
2. The liquid CO on bottom of stripper flows paralleled through three expansion valves, but only one of the temperature of the...
dear jamesbanda
you have to identify your level transmitter type first.
If the level transmitter type is float, it is easily to install the magnetic level switch on the chamber.You can consult with instrument maintenace people.
I don't think the tray will seriously damaged by the reboil return...
Could some one tell me what is the difference between NaOH % and free NaOH %?
From analysis report for the caustic soda solution, only NaOH % data was detected and didn’t any free NaOH % contain in the solution. The laboratory person said the caustic soda was losing ability to remove hydrogen...
dear Simpson,
There are a point in your article I could not understand. Would you mind describing more clearly for me? thank you.
“If you drift to 35 psig then the second stage will take extra load.”
In my experiences, most process reciprocating compressor discharge pressure are varied with...
