Making Steam the RN Way

I had a few old posts on this subject.

A-type boilers were definitely a prewar design in the USN.

The Russian Navy Needs to Have a Propulsion Examining Board

As an old steam engineer, let me say this: There is no excuse for an oil-fired warship in good condition to send up black smoke, especially in this quantity.

Shit, coal-fired ships often didn't smoke that badly.

The smoke suggests to me that either the plant design or the snipes of the Admiral Kuznetsov suck. Proper naval boilers have economizers; the hot flue gasses from the boiler fires pass over the economizer tubes to pre-heat the feedwater prior to it being fed into the boiler. The fuel savings of economizers are significant, something like 10%, but that level of efficiency can't be achieved if the economizer tubes and their vanes are covered with soot.

Even if the ship was "blowing tubes" (using steam to blow the soot from boiler tubes), for that much soot to be blown off indicates that the plant is running too rich a mixture. There should be no smoke visible from a properly-fired naval boiler.

This article may overstate things, but I am prepared to believe that the Kuznetsov is a piece of shit.

Stick-Shift Boilers

(Might want to read this first.)

Let's say that you're on a steam ship and the order comes down to increase speed. The throttleman in the engine room acknowledges the bell change and opens the throttle. More steam is admitted to the turbines and they spin faster.

The real fun is in the fire room. When the throttle is opened, the first thing that happens is that steam pressure drops in the main steam line. Because of that drop in pressure, the level of water in the boiler goes up. But that's just a momentary reaction.

In response to the lower steam pressure, the automatic combustion control (ACC) on a modern 1,200lb. steam plant[1] did three things and, in a well-maintained system, did them very well: It would add water to the boiler, increase the firing rate at the burner front and speed up the forced draft blowers. The Burnerman would, as ordered by the Boiler Tech of the Watch (BTOW), cut in more burners.

The Blowerman (or "Lower Levelman") would, if ordered, start an additional forced-draft blower. Each boiler had two blowers, but in normal peacetime steaming, only one blower per boiler would be running.

It took the boiler techs a long time to come to Jesus on ACC systems. There was a special Naval Enlisted Classification code for an ACC technician. One of the things that got Insurv riled up was the failure of surface ships to properly set up, maintain and run ACC systems. When things like that happen, the way that the surface line community[2] handles things is to publicly fire people until everyone gets the message.

The thing was, of course, that the senior boiler technicians had learned their jobs on World War Two-era ships. Those ships had 600lb. steam plants that were manually controlled. The Upper Levelman stood watch by the boiler water-level gauge glasses and he controlled the rate that feedwater was added to the boiler. The Burnerman controlled both the number of burners and the amount of fuel oil that was fed to the burner front. The Blowerman controlled the speed of the blowers.

So now the Throttleman opens up the throttle. The Upper Levelman sees the water level rise in the gauge glass, but he knows that is a temporary effect, so he makes ready to add feedwater. The Burnerman sees the boiler's pressure drop, he increases the firing rate. The Blowerman speeds up his blowers to feed more air to the firebox.

Those three men, naturally, were told what the speed change was and they could react based on experience. But the Blowerman and Burnerman rarely were able to harmonize exactly during big speed changes. Given the choice between too little air and too much air, the Blowerman always opted for too little. Too little air meant that the boiler would emit black smoke out of the stack. Too much air and the boiler would emit white smoke. White smoke was finely atomized fuel and, as you might suspect, a white smoke condition was dangerous: You would get a fuel-air buildup in the upper works of the boiler and the stack and then, if it were not brought under control quickly, very bad things would happen.[3]

Ships with boilers that had tuned ACC systems didn't emit smoke on power changes. If a boiler that was run on an ACC emitted smoke on a power change, that was a sign that the ACC wasn't working properly.[4] So if you see photos or video of a Navy steam-powered warship blasting out smoke as she accelerated, you probably were seeing a ship with a stick-shift plant.
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[1]"Modern" being "post Korean War".
[2] Our motto: "We Eat Our Young".
[3] The rule was that if white smoke couldn't be eliminated in a minute or less, the boiler's fires were pulled and the boiler wrapped up.
[4] There was a test called a "boiler flex" in which the Throttleman would rapidly spin the throttle open or shut in order to change the steam demand across 80% of the boiler's operating range, in order to stress-test the ACC system. This was an OPPE fail item.

Helpful Guidance From the Afloat Staff

This is no shit[1]:

There was a task group of warships heading into Yokosuka, Japan. One of the double-ended cruisers had had a boiler casualty and was sort of limping in on one screw. The demineralizer in one of the plants had failed and, instead of removing minerals from the condensate coming from the main engine, had dumped minerals into the feed water system. That salts up a boiler faster than you can think of it.

Besides replacing the resin guts in the demineralizer, the affected plant has to be washed out with copious amounts of fresh water, then rinsed with a citric-acid based wash, and then rinsed again. It was that cruiser's dumb luck that she was steaming all four boilers at the time, which meant that both boilers in the affected plant had to be opened up and cleaned.

After the engineers had stopped steaming the salted-up plant, the Chief Engineer recommended to the Captain that he place the ship on water hours. "Water hours" meant that unless you were a cook or you were covered in grease and oil, you didn't get to take a shower. And you might as well wear the same uniform for awhile, as the ship's laundry was also secured. It didn't take very long until the inside of the ship smelled like a locker room.

The plan that the Engineer recommended to the Captain was to do all of the flushing of the salted boilers at sea, so that they wouldn't have to worry about disposing of the water used to flush the boilers.[2] Once in port, where a Culligan truck was available, they would then close out the boilers and hydrostatically test them.[3]

All of this, of course, was the subject of a CASREP and follow-on updates. So nobody could say that anyone in the staffs wasn't informed.

So now it's a little after 2300, two days before the task group is to arrive. One of the bright young lads on the embarked staff on the aircraft carrier got on the secure UHF circuit[4], called over to the cruiser and asked to speak to the Engineer. CIC called down to Engineering. The EOOW called the Engineer in his stateroom and told him that he was wanted on the Red Phone.

The Engineer was not happy. It seemed as though he was going to be able to get a good six hours' of uninterrupted rack time, which was almost unheard-of. So he pulled on his filthy uniform and went up to Combat. The CICWO pointed to the correct handset. The Engineer picked it up. The conversation went about like this:

"Staff, Cruiser, Chief Engineer speaking. Over."

"Staff here. Due to the sensitivity surrounding discharges from warships, we want to make sure that you complete your boiler flushing well before we enter Japanese waters. Over"

In the cruiser's CIC, sailors swore that they could see smoke wisping from the Engineer's ears. He keyed the handset and responded. "Cruiser, Engineer here. We had no idea that there would be any political ramifications from intentionally dumping pollutants into Japanese waters. It never occurred to us that they might not approve of it. We will take that into account and make sure that we finish well before then. Anything further? Over."

"Staff, roger, thank you. Out."

Supposedly, the bright one on the staff was pleased with himself, until it was gently pointed out to him that the Engineer's response was heavily laced with sarcasm. By breakfast the following morning, every engineering officer throughout the task group was laughing about it.

The watch in the cruiser's CIC held their laughs until the Chief Engineer had left Combat, slamming the door behind him.
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[1] Some details have been changed to protect the guilty, at least one of whom is still on active duty
[2] Why there was such concern over dumping water that had salt and/or diluted citric acid was more a matter of politics than science.
[3] Any time you opened up a boiler, you had to hydro it. High-pressure steam leaks are bad news.
[4] Also known as the "Red Phone", from the color of the remote stations in CIC and the Bridge.

Steam Applications (non-naval)

Steam power had some interesting applications, other than driving ships, trains and generating electricity.

This is a website about a very large steam pump, the Cruquius Engine, that was used to help dewater Holland.

This is an animation of the engine room. This is an animation of the operation of the engine and pumps and a schematic animation to show the basic flow of steam.

The engine ran for something like 70 to 80 years.

(H/T)

Fires Lighted, 1A Boiler

(It might not hurt to occasionally refer to the diagram here.)

So we now have fires lit in 1A boiler. Naval boilers, when not steaming, are always laid up in a manner that helps prevent corrosion. The most common short-term layup is a "steam blanket", where steam that is supplied from either a steaming boiler or, in port, from a steam supply line from the pier, is piped to the top of the boiler to keep air out. If we have a steam blanket, that means the water in the boiler is somewhat warmed. You secure the steam blanket, obviously, just before light-off.

Initially, not much happens. The boiler slowly heats, as you can only run one burner with the electric forced air blower. If you put in more fuel than the light-off blower can supply air for, you will emit black smoke and that is bad form. Once you get to about 50psi on the steam pressure gauge, you can open the outlet for the boiler and start to feed steam to the steam pipes to warm them up.

Gradual warming up of the steam lines is critical. The steam lines at light off are at room temperature. At operating pressure and temperature, the main steam line has a steam pressure of 1,175# at 950degF. You must heat the lines evenly and slowly in order to prevent uneven expansion, which in turn, leads to leaks around the gaskets that connect valves to the pipes and sections of the steam pipes to each other. At this point, the main steam valves are all closed (they are large gate valves). Each main steam valve has a small bypass line to equalize the pressure on either side of the valve before opening it; the bypass valves are opened, in sequence, to heat the steam lines. You pressurize and start to heat each section before you start on the next one. Then you open the main steam valves and begin feeding steam, now at 100# or more, through the plant.

Now stuff starts to happen. You can start rolling the main forced draft blowers, which are powered by steam turbines, and you can secure the electric blower. The main forced draft blowers can put out a lot more volume of air, so you can start a second burner. Once you have one burner going, when you start more, you just open them up, as they will light off from the burner in use. You also start the steam-driven main feed pump, as it can supply feedwater at higher pressures than the main feed booster pump, which is what you were using.

Both the man forced-draft blowers and and the main feed pumps exhaust their working steam into the auxiliary exhaust system, as do all steam auxiliary systems. The aux exhaust (which are not liquid, this is steam at 5-25# or so) feed to the deaerating feed tank (DFT), which both deaerates the feedwater and supplies feedwater to the main feed booster pump. The aux exhaust also dump into the condensers for the ship's service turbogenerators (SSTGs) and the main engines. But you cannot do that until you have enough steam pressure to roll the SSTGs, as the aux steam will unevenly heat the turbines of the SSTGs, and that is a bad thing.

The problem is that the DFT cannot handle the steam load that is being dumped into the aux exhaust, so the aux exhaust system overpressurizes and lifts the relief valve, which vents out the stack just below the smoke vents. A steady cloud of steam vapor comes out the vents, and that is water that has to be made up from the feedwater tanks. This is a tricky time, you have to get pressure built fast enough so you have enough steam pressure to at least one SSTG rolling so you can cut in aux exhaust to its condenser. This is where the EOOW doing the light-off of the plant has to pray that the Chief Engineer doesn't go topside and sees the steam blowing out the vents, as regardless of whether the light-off is going well or not, you can bet the CHENG will have something caustic to say about the feedwater being used up.

Once you can roll a SSTG and get aux exhaust cut into the SSTG's condenser, the steam system becomes closed and you aren't using that much feedwater. But until you do, from the time you blow the relief valve, you use a lot of feedwater. It is considered to be bad form to have to call the Culligan truck to top your feedwater tanks off once you start the light-off. It happens to everyone sooner or later, but if you make a habit of it, your ship will get a bad reputation as being unable to do a light-off unassisted, which means the Captain will hear about it at various social parties, if not officially from the Squadron or Group Commanders, which means you will hear about it from the Captain and the conversation will not be pleasant.

Once you have one SSTG rolling, then you can crank up the blowers and build steam pressure faster. When the 150# aux steam lines in the Engineroom are up to pressure, the machinist's mates can start the evaporators so the evaps can begin making distilled water from the surrounding water in port, so you can refill the feedwater tanks. This water has to go to feedwater; you don't cut the evaps to the potable water tanks in port unless it is an emergency, for the water then must be heavily treated to be safe. You are about where you can start feeding steam though the "hotel" system to feed the heating systems, the water heaters and the galleys, and you can secure the steam lines from the pier.

Now you are up to main steam pressure. You bring one SSTG up to speed and it feeds to the main electrical switchboard. You call the Quarterdeck and have the word passed over the ship's PA system (the "1MC"): "Place all electronic equipment in standby while the ship shifts from shore power to ships' power." You wait about five minutes, then order the EM on watch to switch to ship's power. Using a synchroscope that is built into the switchboard's panel, the EM matches the phases of shore power and the output of the SSTG, controlling the SSTG to run at a slightly higher frequency. When the needle of the sychroscope is between 11 and 12 o'clock, the EM parallels the SSTG to shore power and then immediately trips the breaker to shore power.

You wait a few minutes to see if everything is stable. If it is, you call the Quarterdeck and ask them to pass the word "the ship is now on ship's power."

You are now "auxiliary steaming." The only services the ship is receiving from the pier are fresh water in, sewage out, and telephones.

On the USS Theoretical: Prepare to Light Fires, 1A Boiler

The first thing you have to know is when you are sailing and for what reason. If you are going out on a deployment or for a major exercise, you were required to be on stable ship’s power 72 hours before sailing, to give a fair amount of time for the electronics types to tweak their gear and for the radiomen to have shifted over to the message traffic frequencies. (Message traffic for the ships that were in port was handled by the ashore communications station.) Which means that you have to light fires at least four hours before that time, unless you’re going to cheat on the 72 hours. If your sailing time is 0800, you are going to cheat, just to be fair to the engineers. If you are going out for a short exercise, then you light off the day before.

The division officers and chiefs for B, M and E divisions have to draw up an in-port steaming watch bill for the approval of the Chief Engineer, so that everyone knows when they are on duty. Unlike cold-iron conditions, the Duty Engineer must be an EOOW.

You need to make sure that the feedwater tanks are at 100%. You can’t just fill them from the potable water lines feeding the ships at the piers, feedwater is deionized to prevent any contamination of the boilers. So you need to get the deionization truck, known as the “Culligan truck”, to filter the potable water from the piers and feed it to the tanks.

And finally, you want to light fires during the day, for you want to make sure you have an awake and alert team on duty.

The Water King will do a series of tests on the light-off boiler to make sure the chemistry is within limits. He may have to treat the boiler before light-off or soon after. In a worse-case scenario, he may recommend dumping the boiler and refilling it (call the Culligan truck). The Oil King will check the fuel oil service tank for contamination. The chiefs of each machinery space will do a check to make sure that no vital equipment is out of commission and that all of the “red tags” and “yellow tags” that need to be cleared are cleared.

The fireroom crew has to run a “man aloft” chit to make sure that all of the radars on the ship and any ships nested alongside are shut down. Any rotating radar antennas have to be secured. This has to be done because the BTs must now climb the stacks to remove the herculite stack covers, which keep rain from falling into the stacks when the boilers are offline (and rusting out the insides of the stacks and the economizers on the boilers).

By now, you might be wondering how anyone can keep track of this, for the preparations for lighting off take hours, if not more than a day. The answer is by the use of a set of procedures known as the Engineering Operational Sequencing System, or EOSS. EOSS is a series of laminated checklists in looseleaf binders with laminated pages for every watch station in the plant. If you go to start up or shut down any piece of machinery in the plant, there is an EOSS checklist for it.

The fireroom crew now is in its final preparations with the light-off watch on station. They start the fuel oil pump, which begins to circulate fuel oil from the fuel oil service tank to the burner front of the boiler and back to the service tank. When the lines are up to pressure, they are very carefully checked for leaks. Fuel is recirculated from now on, though the supply lines to the individual burner are closed. They start the electric forced draft blower to feed air through the air casing around the boiler and into the firebox through the vanes around each burner. The air casing must be pressurized to a certain number (measured in “inches of water”, not PSI) for a specified minimum time before lighting off.

Now we are ready to light fires.

The fireroom watch is in place. The light-off is done under the command of the BTOW. The EOOW must also be present. When lighting fires, only two sailors are permitted in the “firing alley”, the lowest level catwalk which runs in front of the firebox, the Burnerman and the sailor who is assisting in the light-off, usually the Lower Levelman. The Burnerman is wearing a welder’s jacket, a faceshield and welder’s gloves. The light-off torch is made of metal round stock about 1/4" thick and it is about six feet long. On one end, some rags are wrapped with bailing wire to the torch and soaked with fuel oil. There is a round metal shield that slides along most of the length of the torch. The other end of the torch ends in a triangular handgrip.

The Burrnerman’s assistant lights the torch, using a Zippo lighter, never a match or a butane lighter.* The Burnerman turns the torch to make sure the torch is burning properly and then pronounces that he is ready. The vanes feeding air to the firebox are closed to prevent blowing out the torch. On the order of the BTOW, the torch is inserted as far as it will go through the light-off-port; the port cover is then closed as much as possible onto the shaft of the torch. Between the port cover being mostly closed, the safety gear worn by the Burnerman and the round shield on the torch, the Burnerman is well-protected against a flareback, when a boiler being lit off shoots flames out the light-off port.

The Burnerman looks through the burner’s observation port and checks to see if the torch is burning. “Torch still lit” is the announcement everyone wants to hear.

The BTOW commands: “Light fires, 1A Boiler.”

The Burnerman opens the burner’s fuel valve. The Lower Levelman then opens the feed valve to the burrnerfront and starts loudly chanting: "One thousand one, one thousand two, one thousand three.” If by the time he finishes his count, the Burnerman hasn’t yelled “Fires lit,” the Lower Levelman will shut off the feed valve. In that case, the torch is withdrawn and extinguished, then a periscope is inserted into the light-off port to inspect for spilled fuel oil. In a bad case, the burnerfront will have to be opened and people sent in to clean up the oil, but usually you only have to re-purge the firebox.

“Fires lit, 1A Boiler!” The Burnerman fans the air supply vanes open and shut to make sure that the burner is stable and stays lit. The Lowerlevelman opens the fuel supply valve the rest of the way and secures the return valve to the service tank. The Burnerman removes the torch and shoves it into the torch holder (a long pipe closed on the far end), which extinguishes it. The BTOW calls “fires lit” on the intercom throughout the hot plant, the MMOW in Main Control logs it in the Engineering Log and announces that hearing protection must be work in the plant. The MMOW calls the DC Central watch, which, in turn, calls the Quarterdeck to inform the Officer of the Deck. The Petty Officer of the Watch logs it in the ship’s Deck Log.

And now the fun begins.
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* The use of a Zippo was by regulation, not by custom. There was likely a good reason for it, though I never was told why.

Making Steam the Navy Way

A while back, a friend of mine asked me what happens if there is a loss of steam pressure in an operating naval boiler. Short answer: The generating tubes melt. The boiler could blow up.

Long answer: Take a look at the schematic of a 1200psi naval plant. look at the boiler on the upper left corner. See the circle in the boiler labelled "SD" and one labelled "WD" and the two curved lines between them? Those are the steam drum and the water drum. (Click on it to enlarge it)



Naval boilers do not have circulation pumps. There is a steam drum at the top, the water level is kept at the half-full mark. The water drum is at the bottom, it's also called the mud drum. The two drums are connected by the steam generating tubes and the downcomers. The generating tubes are in the firebox, the downcomers run between the boiler and the air casing. (There are also screenwall tubes, which protect the sides and rear wall of the boiler casing. Those tubes also generate steam, but not a significant amount.)

If you've ever closely watched a pot of water boil on a gas burner, you'll see there is a point where bubbles are coming off the bottom of the pot where the flames are hitting the underside of the pot. The cooler water goes down to where the flames aren't hitting the other side to replace the steam bubbles coming up, you are watching natural circulation. That's how a naval boiler keeps water circulating; slightly cooler water goes down the downcomers to the mud drum and then it replenishes the water in the generating tubes that has turned to steam.

Look again at the pot of water. When the little bubbles are coming off the bottom, that's called "nucleate boiling".

So let's start with a cold boiler and light fires. As the water heats, you get nucleate boiling off the sides of the tubes. The little bubbles go up the center of the tubes and rise to the steam drum. This is "bubble flow", the tubes are about 5% quality (5% steam) . As the water has more heat applied, the bubbles become larger and now you have slug flow. More heat and the center of the generating tubes is just steam with a ring of water around the inner wall of the tubes, which keeps the tubes cooled. This is annular flow and it's about 30% quality; you still have nucleate boiling going on and water is being replenished by natural circulation. The steam coming out of the generating tubes into the steam drum is heavily saturated with moisture.

This is as far as you can fire a boiler at normal pressures of 1,200psi, you will reach the "endpoint of combustion", you can't get any more fuel through the burner nozzles.

Now, say you lower the boiler's operating pressure below the operating set point. The water boils at lower levels of heat, so you can get more steam generated in the tubes. Then you can get to spray flow, where you still have nucleate boiling but the tubes are only just wetted on the inside and the steam is about 60% quality.

Lower the pressure a little more and you get to DNB or "departure from nucleate boiling", where there is no longer any water on the inside of the tubes. The steam is 100% quality or even slightly superheated, no moisture is carried over to the steam drum ("endpoint of carryover"). This is, to quote Rod Machado, A Bad Thing, for the generating tubes are designed to be cooled by the water inside of them. The tubes will start to melt.

If you can push it even hotter, you will generate so much steam that the downcomers will not be able to supply water to the water drum. This the endpoint of circulation and at this point, the damn thing may very well blow up. This is like having the water level in an old steam locomotive or traction engine drop below the crown sheet over the firebox.

So, to prevent that from happening, if the main steam pressure drops below 1080psi, the fireroom crew will call out a low pressure casualty and they will wrap up the boiler.