Discussion in 'Electronics' started by Ken Bracewell, Jan 29, 2013.
And spray dawn dish soap on the water in the US and go to jail almost...10K fine
Clean-exhaust, meet the EPA and the USCG ...
I suggest a quick glance at 40CFR110.4 to start. Maybe this would work in Nigeria but using dispersants to sink oil slicks will get you all kinds of unwanted attention in most countries.
“certified green” emulsifier ???
Success So Far
So we've now installed two 12KW Heating Units on the generator exhausts (one on each) and they seem to be doing exactly as promised. Our exhaust temperatures are regulated above 375C and the heaters drop offline when they are not needed.
Hull sides are staying clean and my deck crew are ready to buy MARMOT a beer at the first opportunity.
The only unforeseen issue so far occurs when we are running the second generator for the bow thruster. Since it has no load most of the time, the heaters are running at full tilt and we have to manage the load on the house generator.
We are also using a fuel additive, but I won't mention the product until I've put enough hours to make a qualified judgement.
What about a system that takes the electrical end offline on the generator running the electrical when you engage the thruster (that way you have a thruster in case of an emergency), and you'll have full power for the thruster at the push of a button.
Then, only running the 2nd generator for the thruster only, only in inland waters which usually isn't for too long on a yacht your size. Or do you do a lot of intracoastal type cruising?
There is no need to get too complicated. The generators cannot be paralleled, so the only reason to start the second one is if I need the thruster. Managing the load is fairly simple, and you're right that it only runs for short periods of time unless we are running in tight quarter for long periods.
The way you operate is correct for the installation you have. The only reasonable means to avoid running the (hydraulic source) generator with no electrical load is to modify your switchboard to provide for a split buss where vital systems are powered off one generator and non-vitals come off the generator used for hydraulic power. When you are finished with the thruster, close the buss tie and power everything off the online generator. Considering that the bow thruster is a very very low use item even that seems overkill.
The idea of going "dark ship" every time you run the bow thruster is amusing to say the least. I am reminded of the old prison movies where the lights dim when they pull the switch on the electric chair ... everyone looks up and shudders.
There are many vessels that use a dedicated bow thruster engine, either geared to the thruster or driving a hydraulic pump. That engine does nothing else for a living and lasts as long as the boat.
We could size the heaters so that the bow thruster engine (it isn't a generator at that point is it?) will have adequate exhaust temperature when running at zero load but given the time it actually runs there is no cost/benefit advantage in doing so.
A heater running full tilt is doing what it is designed to do and doesn't wear out any earlier. The temperature of the sheath (the tube that holds the resistance element - the part that you see) is what matters and as long as it is below its design temperature it will last for a very long time. When the generator is unloaded, the sheath is cooled by the exhaust, when it is loaded, the power into the heater reduces the temperature proportionally. It is a win-win with regard to operating temperatures. Your system also has a safety feature that ensures the sheath will never exceed a very large margin below its maximum allowed.
This is true,but to save energy & fuel, sequencers make a lot of sense. Lets says you have a 18 Kw electric heater element. In HVAC they are used when the outside airtemp is below that of a heat pumps capability. So 100% electric auxiliary heat elements are installed (3.412 btu per watt) . A 18 Kw unit would have several sequencers installed bringing say 6kw online every 20 seconds to keep peak demand down.
Now for the use here a small modification could be made so if you only need 6Kw, only 6Kw will come online. If 12Kw is needed only 12 Kw will come online and so on,until all the electric heat is on....if thats what is needed. But many times the generator may not need the entire heat load,so only whats needed comes online to meet the minimum temperature requirements.This will keep the exhaust temperature that is needed but not add extra heat load that uses extra fuel to generate.
Many of the current crop of electrically assisted exhaust cleaners do operate in stages.
These heaters don't "sequence." If the power required to deliver 350 - 400C exhaust into the filter is only 2.863kW then that is what is consumed. No "extra heat" is produced and no power is wasted. I could put a 100kW heater in the system and it would still only consume 2.863kW.
Sequencing is an archaic technique. If shoreside systems used that and had to pay the utility for "demand charges" they would pay through the nose every time a heater kicked in. We have come a long way in industrial control technology since the 1960s.
On a boat, the sudden inrush of a sequenced heater kicking in creates an instantaneous load on the generator that few governors can handle, the result is a puff of smoke and soot and a power surge for the voltage regulator to deal with along with EMI spikes.
Our technique ramps up the power on startup over a minute or so (programmable) so that there are no inrush issues, and smoothly and proportionally delivers only the power required to obtain the desired outlet temperature that - within a broad range - remains constant regardless of generator load without the drama and theatrics of switching heaters in an out.
This is what I meant by a small modification..........Your still sequencing the power..... just the rise time, fall time and run time is in milliseconds using solid state components. Unlike mechanical switching (ps: I wasn't alive in 1960) Your probably using a PID with a SCR. I guess you can't get too specific on the forums or anyone could build one.
Well, not really ... I mean, anyone can build a boat, right? I just want to keep a safe distance from posting infomercials here.
Now that you are on this side of the pond, any updates?
P.S.- Welcome back.
I just realized that I haven't yet responded to this.
So, after more than 15,000nm I am thrilled with the combination of MARMOT's heater solution and the GO2 fuel additive.
More importantly, my deck crew is having a much easier time keeping the topsides clean, and the paint is being preserved.
Thanks MARMOT for reaching out and helping to solve this problem!
Thank you Ken for the endorsement! I am very pleased that the system worked as claimed and the deck crew work load is reduced along with paint damage. It's nice when things work the way they are supposed to.
I'll try real hard to avoid sounding like an infommercial but we are installing a growing number of systems to cure soot, smoke, stink, and oil'soot slick problems and to rescue other filters that don't work properly for a number of reasons.
Marmot if you can e mail me a proposal with your partner co's endorsement for 4 x 770kw Gensets please hurry up or we will choose an existing brand as there is no viable alternative.
You are right, we are the only alternative to something you don't want. Seriously though, if this means you got that project then congratulations! Well done.
Note is in the mail ...
How sensitive is the heater system you have adopted and the GO2 additive to differing fuel types brought about by biodiesel use?
Good questions. We have no direct (or to my knowledge - indirect) experience with biodiesel or biodiesel/petroleum fuel blends on any of our installations, or any other DPF installation.
The heater portion of the system is not effected in any manner. The system control algorithm might need to be tweaked to accommodate the slightly different chemistry of the exhaust and its impact on overall system performance but aside from some questions about the filter substrate itself, I don't think it will matter much in the blends normally available.
There are two studies linked below which may either provide some enlightenment or add to the confusion. Apparently the higher oxygen content of biodiesel is "good" for reducing soot and improving filter regeneration (soot burnoff), but the higher inorganic content may lead to shorter cleaning intervals due to higher ash loading.
One study shows potential for filter damage due to higher acidity of biodiesel exhaust constituents but does not seem too indicate the damage produced has any great effect on filter performance or life.
With regard to the fuel additive. I am a proponent of the cerium based additives because the chemistry has been well proven for well over a century of use as a combustion catalyst. It is only new to our application because until recently there has been no way to deliver it consistently to the combustion chamber in the proper proportion.
While I don't have numbers to prove it, my opinion is that the oxygen transport capability of cerium oxide catalyst reduces the temperature required to "light off" a DPF. Our experience with this technology shows very clearly that low exhaust temperature at the face of the DPF is the source of nearly all the problems associated with them. Consistently low temperature is a terminal condition and anything that will maintain the filter at or above minimum regeneration temperature is a good thing.
We will have our test generator in place shortly so that we can document the impact of different fuels, additives, and operational conditions. Hopefully yours will be one of the questions we can answer definitively. I tried to get a filter manufacturer and an additive manufacturer to cooperate in test on a generator to document compatibility but to this date none of them have. We are going to do that ourselves.
I don't believe the figures presented by other suppliers for the percentage of time above a certain temperature to establish regeneration are entirely accurate for real world operations or applications. The life of a marine generator in a yacht application is a world away from terrestrial or even commercial marine use.
Sitting here and thought it would be nice to check the FLL webcam.
Saw a boat that looked familar and checked AIS to see who it might be - 'twas you.
Is the fix still keeping everyone happy?