Not only electrical, but...

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hardworkingstiff

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Wilmington, NC
Customer would like to blend diesel and biodiesel. Unit should be adjustable from 5% to 20% blend.

I was thinking of feeding a common line from separate tanks with submerged pumps and having a PLC control electrically actuated valves. Pulser meters would need to be on each line so the PLC would know how much fuel was passing through each line and the PLC could adjust the ball valve position to keep the blend ratio accurate.

Questions:

Do you think this simple design can work?

Can you recommend the PLC and valves?

Thanks,
 
whats a pulser meter - sounds like it would work
methinks that ball valve position will not give good control
the only meters ive used when doing something like this is a flow style meter - its got a little fan looking vane inside of it
 
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Check regulatories. In Alaska we are allowed to run diesel almost straight out of the cracker for off road machines. In town, better have the right mix, in the tank. The state boys know by the color of the fuel (performance doesn't matter to them) what your running, if they happen to check.
 
Rockyd said:
Check regulatories. In Alaska we are allowed to run diesel almost straight out of the cracker for off road machines. In town, better have the right mix, in the tank. The state boys know by the color of the fuel (performance doesn't matter to them) what your running, if they happen to check.
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The color of the fuel is for the purpose of road taxes. Dyed fuel is off road, and the fines for using it in on road vehicles can be 5 figures.

I'm talking about custom blending of biodiesel and regular diesel. Biodiesel being made from oils/fat/etc.
 
I would use metering pumps way before I'd use flowmeters, pumps, and motorized ball valves. That will not only keep the cost way WAY down, but will eliminate a lot of engineering and error.
 
mdshunk said:
I would use metering pumps way before I'd use flowmeters, pumps, and motorized ball valves. That will not only keep the cost way WAY down, but will eliminate a lot of engineering and error.
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Marc, can you control the flow rate through a metering pump?

I was involved in installing a custom system designed by an Engineer that pushed gas and oil 1/4 mile (in 2 separate lines) then blended it together for 2-cycle outboard engines. We modified it a few times to work out the bugs. The biggest problem he had was controlling the flow of each pump. His theory was to use PD pumps, so they would always pump the same amount of product for a perfect blend. Too many little things messed up the blend. They finally (after 3 years) abandoned the design.
 
hardworkingstiff said:
Customer would like to blend diesel and biodiesel. Unit should be adjustable from 5% to 20% blend.
...
Thanks,
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Wow, you might check the State Laws about this situation, and what conditions, Etc. Etc. I do recall something about it here, but can't state specific's.

Other than the EPA, I've heard the it's all old hat in the farming and rural area's, and being used alot more...
 
cadpoint said:
Wow, you might check the State Laws about this situation, and what conditions, Etc. Etc. I do recall something about it here, but can't state specific's.

Other than the EPA, I've heard the it's all old hat in the farming and rural area's, and being used alot more...
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This is a RFP from the State ports. It's just a typical fuel system EXCEPT they want to custom blend the bio and regular diesel (not so typical).

I did find out that SPATCO has about 50 units like this in the field, but... really pricey.

Edit: Not like I described, they use a PD pump, PLC, pulse meters and variable speed control on the PD pumps.
 
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hardworkingstiff said:
One more thing. We need to fill some vehicles at 3-10 GPM and other short trucks at 60+ GPM.
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By 60+ GPM do you mean gallons per minute i.e. 1+ gallon a second?
In F1 racing they can achieve around 2.6 gallons a second but it requires a team to do that and, as the 2008 season showed, it isn't foolproof.
Anyway, at that sort of rate, I think you'd maybe need the fuel to be already mixed. That would give you a few options on how to produce the required blend.
For measurement, I agree with you on the idea of using a flow meter but controlling flow with a valve is, at best, coarse and inefficient.
In UK water industry it was one of the best justifications for converting to VSDs on pumps.
 
081209-2238 EST

hardworkingstiff:

Is it necessary to precisely mix these as the fuel is being loaded?

If you used turbine flow meters to monitor quantity you should be able to get quite precise total quantities for any desired interval. Then use approximate settings of the flow control valves for the mix.

You would know the total amount to be transferred. From this the total amount for each component can be calculated. When the total amount for each component is reached its flow is turned off. If more uniform mixing is required during filling, then work in smaller subincrements.

.
 
hardworkingstiff said:
it's a meter that has a switch that opens/closes as fuel passes thru, get the right ones and you can be accurate to less than 1 cu. inch (231 cu. inches per gallon)yea, I'm concerned about that too.
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if this is a batch tank that fuels vehicles then you should be fine; i thought for a second that this was a self containd unit that was part of a vehicle - if so then i dont think it will work
this is some stuff i have worked with and recomend
http://www.dultmeier.com/catpages.asp?page=E0387

- i do not know if it will work in your application but it is good stuff - you can program the rates that you need and it will do the rest - probably wont work with your pulser meter though the flow meter i speak of works really well with their acutated valves
sounds like your pulser meters are more acurate - they sell stainless steel pumps that will inject a predetermind amount into another mixture
60 gal/min seems a bit on the far fetched side - if you make it work let me know i would be interested in seeing how you did it
 
If I was going to design that system, I would probably use positive displacement gear pumps with DC motors.

Flow control could be acheived by using RPM sensors on each pump motor.

The sensors would produce input signals to a small PLC that would in turn supply a reference voltage for the DC drive(s) that operates the pumps.

Size the pumps for the maximum flow that you require, and let the PLC turn the motor(s) speed up or down according to a pre-selected ratio.

The positive displacement pumps will give you a accurate and consistent flow rate that is dependant on the pump RPM.....control the speed, control the flow.

Just a idea
steve
 
hillbilly said:
If I was going to design that system, I would probably use positive displacement gear pumps with DC motors.

Flow control could be acheived by using RPM sensors on each pump motor.

The sensors would produce input signals to a small PLC that would in turn supply a reference voltage for the DC drive(s) that operates the pumps.

Size the pumps for the maximum flow that you require, and let the PLC turn the motor(s) speed up or down according to a pre-selected ratio.

The positive displacement pumps will give you a accurate and consistent flow rate that is dependant on the pump RPM.....control the speed, control the flow.

Just a idea
steve
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Sound idea but a PD pump for 60 GPM might be quite pricey.....
 
hillbilly said:
If I was going to design that system, I would probably use positive displacement gear pumps with DC motors.

Flow control could be acheived by using RPM sensors on each pump motor.

The sensors would produce input signals to a small PLC that would in turn supply a reference voltage for the DC drive(s) that operates the pumps.

Size the pumps for the maximum flow that you require, and let the PLC turn the motor(s) speed up or down according to a pre-selected ratio.

The positive displacement pumps will give you a accurate and consistent flow rate that is dependant on the pump RPM.....control the speed, control the flow.

Just a idea
steve
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Good idea.

I would however use AC motors and would count the rotations then compare and adjust.
 
I've found 2 sources that have packages all ready and many in the field. Both basically use a PD pump with variable speed controls for injecting the bio into the low-sulpher diesel. They meter both products (the diesel is pumped with a standard submerged pump in the diesel tank) and modify the bio diesel to obtain the correct blend. Both claim to have accuracy to less than 1%.

Thanks all.
 
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