NOAA Teacher at Sea
Dieuwertje “DJ” Kast
Aboard NOAA Ship Henry B. Bigelow
May 19 – June 3, 2015
Mission: Ecosystem Monitoring Survey
Geographical area of cruise: East Coast
Date: June 2, 2015
Chief Engineer Tour of Engine Room!
SCHEMATICS- Drawn by John
Chief Engineer John Hohmann took me on a tour of the Engine room here on NOAA Ship Henry B. Bigelow. It was fascinating to learn all of the components that make this type of research vessel work. The electrical components, the seawater distillation apparatus, biological sewage treatment, etc. It was an amazing tour. The Bigelow has a diesel-electric drive system using four diesel generators to power to two electric motors. The motors turn one shaft which rotates the propeller. Overall rated horsepower for main propulsion is 3017hp.
The sewage enters the aeration compartment where it is digested by aerobic bacteria and micro-organisms, whose existence is aided by atmospheric oxygen which is pumped in. The sewage then flows into the settling compartment where the activated sludge is settled out. The clear liquid flows to the chlorinator and after treatment to kill any remaining bacteria it is discharged. Tablets are placed in the chlorinator and require replacement as they are used up. The activated sludge in the settling tank is continuously recycled and builds up, so that every two to three months it must be partially removed. This sludge must be discharged only in a decontrolled area. Photo and Caption info by Machinary Spaces.com
The most fascinating part for me was the Evaporator.
Distillation is the production of pure water from sea water by evaporation and re-condensing. Distilled water is produced as a result of evaporating sea water either by a boiling or a flash process. This evaporation enables the reduction of the 32 parts per thousand of dissolved solids in sea water down to the one or two present in distilled water. The machine used is called an ‘evaporator’, although the word ‘distiller’ is also used.
Boiling process:
The vacuum in the evaporation machine reduces the pressure to 30 inches of Hg or Mercury to boil water at 180F instead of 212 F
The sea water from the ship’s services is first circulated through the condenser and then part of the outlet is provided as feed to the evaporation chamber. Hot diesel engine jacket water or steam is passed through the heater nest and, because of the reduced pressure in the chamber, the sea water boils. The steam produced rises and passes through a water separator, or demister, which prevents water droplets passing through. In the condensing section the steam becomes pure water, which is drawn off by a distillate pump. The sea water feed is regulated by a flow controller and about half the feed is evaporated. The remainder constantly overflows a weir and carries away the extra salty water or brine. A combined brine and air ejector draws out the air and brine from the evaporator.
They need to make their own electricity on board ranging from 110 Volts for phones and computers to 750 Volts for some of the ship propulsion motors. Each of those require various circuit breakers seen below.
Nice job with your engine room post, DJ. I was going to do one, but I think that you captured it perfectly — especially since we are on sister ships (I’m aboard the Pisces). Looks like you had a great time! Those engines are gnarly!