Direct Steam Injection into Cooling Water Line at Pump Suction

Inject the steam into the pump discharge, perhaps. The present scheme is totally f insane.

GA,as usual.

Bear in mind that <...cooling water...> has additives in it to inhibit scaling and biofouling, and operates up to a maximum total dissolved solids before blowdown and replenishment takes place. Raising the temperature by injecting <...steam...> is going to have an effect on both the performance of these additives and the blowdown frequency and duration, as more evaporation is going to take place. Further, as silica is soluble in <...steam...>, the amount of sludge in the <...cooling water...> system is going to increase, leading to increased maintenance activity to remove it.

Operating a cooling water system is a hazardous activity that needs to be properly managed, particularly in respect of the bacterium legionella pneumophila.

Discuss the scheme with the supplier of these additives to come up with a treatment regime that is optimal for the revised arrangement.

Using a heat exchanger to put the heat from <...steam...> onto a proprietary heat transfer fluid for circulation within a closed loop starting at <...60degC...> would be the optimum solution, regardless of current preferences and practices.

If in doubt, consult a local Chemical Engineer well-versed in these concepts.

Are you sure that this is not a vacuum pump designed to allow condensation of steam below atmospheric pressure? The installations look like ordinary end suction pumps, and the discharge ( large diameter) is also piped to the suction. It looks crazy when you see one for the first time. It uses the cooler water to create the vacuum as the steam condenses.

Dear all,

Thank you for the feedback. Its a cooling water pump not vaccum pump. During normal operation it will circulate using cooling water for Reactor, however during no reaction they need to circulate with hot water at 60 deg C so that the fatty alcohol inside the reactor will not solidify. So in order to get hot water at 60 deg C for circulation they directly injection steam at pump suction which they throttle steam via manual valve. This is the current scenario. Please find attached Photo for reference. There is another latest update, i have find out there is condensate tank nearby which most of condensate being send to drain. If i replace the steam injection with this condensate from condensate tank at pump suction to get hot water at 60 deg c, is that it will solve the problem since there will be no steam bubble? Thank you

You could still end up with cavitation depending on the pressure in the pump suction and the temperature of the condensate. The temp of the condensate will likely be similar to the steam, however you won’t have the heat release of condensing the steam. If easy to do, give it a try, without checking the calculations. You will need a heck of a lot more condensate to get the temperature you want, so that might help pressurize the pump suction.

Dear guys,
Thank you for the feedback. The pump suction pressure is 1 barg and and steam injection pressure is 3 barg, hence steam pressure is definitely higher than pump suction pressure.

That suction pressure will help cavitation if you are pumping condensate instead of steam. Your end temp is 60C, so if you control temp into/through pump at 60C, it’s likely it will eliminate your cavitation damage. You just need to make sure you can pump enough condensate to raise the temperature of the water to your 60C target.

Sure. Otherwise the cooling water would get into the steam mains, which is definitely unwanted.

Consensus here suggests that it is a bad design. It cannot possibly have been subjected to a HazOp Study, then, could it (rhetorical question - NNTR)?

"Run, Forrest! Run!"