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  1. butlen

    Build To Order

    Thanks mate, I didn't pick these URLs up when I googled for some reason. I really wanted a discussion with a real person rather than documents, but the first URL gave me the name of a chap at Cambridge University who has exactly the research base i need. I live in Cambridge so I'll go to his...
  2. butlen

    Build To Order

    How does Build To Order work for car manufacturers? Why would you only build a unit when it is ordered, rather than build units, stock and sell, when unit numbers are so high. This isn't my field so I need some basics.
  3. butlen

    Flammability limits of methane at high pressure eg 100 barg

    Its a long time since your post so I won't spend much time on reply. As posted above increased pressure will dramatically increase HEL once you get above 1 atmosphere gauge pressure. LEL is not significantly affected. Temperature also affects HEL at about 7% per 100 degrees C. This is worth...
  4. butlen

    Vegetable oil as fuel for trucks

    I want to put a static engine in a building, but I am not allowed to cause a nuisance to local residents. The nearest neighbours are c.300m away, but a 1400HP set will give off a large volume of exhaust gas. I could take the exhaust very high for better dispersal, but this would have a negative...
  5. butlen

    Vegetable oil as fuel for trucks

    Bytesmiths, Thanks for your comment. Do you know of any way of mitigating the smell in the exhaust? Would an SCR get rid of the smell? I'm talking about reasonably meaty engines (between 1400HP and 3500HP). Thanks Neil
  6. butlen

    Vegetable oil as fuel for trucks

    If I heated straight vegetable oil (ie not waste or recovered) up to say 80 deg C, and put it into a hot Diesel engine, what type of problems would I be likely to see, and would the exhaust smell like French Fries? I am interested in more in detail than "fuel system O rings, pump and...
  7. butlen

    Natural Gas Compressors

    The gas regulator (control valve) is probably causing the pressure drop at the inlet to the turbine. The compressor discharge pressure is higher than the actual gas pressure utilized at the turbine inlet because the control valve needs a differential pressure to control flow. I have looked at...
  8. butlen

    resistance value on pipeworks and Static Earth on plastic pipe

    (FSPO Floating Pumping Storage Offloading Vessel?) In order to prevent electrostatic charges, a typical leakage resistance of 10^6 ohm should not be exceeded for any part of the system. Polyethylene or PVCU will produce a static charge, but both can be manufactured (specially) with additives...
  9. butlen

    safety factor for operating above UEL

    The thing that determines the safety factor above the UEL is the system design itself. For example we operate extraction pumps down to 25% v/v flammable gas (mines gas CH4 plus other alkanes UEL 15%ish) with a 10% v/v safety factor. This may not seem like a large safety factor, but we use...
  10. butlen

    Maximum Working Pressure for PE pipe under given temperature

    You are right, PE has come on a lot in the last few years. What do the manufacturers of the PE material say? Ask your supplier who the manufacturer is and get their technical department to advise what their current material ratings are. In my experience it is not hugely expensive to get a...
  11. butlen

    H2 MIXING WITH FUEL REDUCES CO2 EMISSION?

    Taking note of your plant details the following comments are obvious:- 1) 40,000 tonnes x £5/tonne = cost £200,000 per year 2) As you are quoting £ sterling per tonne I assume you are in the UK. I would guess that CO2 scrubbing will cost a lot more than £200k. CO2 scrubbing on this size and...
  12. butlen

    H2 MIXING WITH FUEL REDUCES CO2 EMISSION?

    Red Please give the following for clarity 1) How much electricity does your site use? 2) How much electricity does your site generate? 3) What type of generators do you have? 4) How much CO2 do you emit? 5) How much do you need to reduce your CO2 reduction by? 6) What does the tax cost per...
  13. butlen

    Hydrogen Flashback Prevention

    Smply buy a detonation flame arrester suitable for hydrogen and fit it in the line.
  14. butlen

    Flame speed

    Ask a bursting disc manufacturer.
  15. butlen

    Explosion Isolation Valve

    saxon what is a fusible link? Is this a type of bursting disc? The real question is - I know a crimped ribbon flame arrester will work if it is maintained properly - it is a passive device, how reliable could I expect an explosion isolation valve to be in service, - ie when I really need it to...
  16. butlen

    Explosion Isolation Valve

    I have been asked to compare the merits of installing an automatic explosion isolation valve (actuated on rate of change of pressure and IR camera), compared to a crimped ribbon detonation flame arrester. Extended burning is not an issue. Medium is saturated methane+air with light particulate...
  17. butlen

    H2 MIXING WITH FUEL REDUCES CO2 EMISSION?

    Red I agree with TD2k that you need to start at first principles. Look at your energy needs and your entire process. Is your current process (for which the electrical energy is required) efficient, or could you reduce your energy demand. Does your process have byproducts, or waste heat, which...
  18. butlen

    CH4 Explosive Limits

    Thank you. I understand that temp is a factor, but pressure is also. As pressure increases the explosive triangle (as shown on a Coward diagram)increases in size, but I don't know how to calculate the increase in size. Do you know how to calculate HEL/LEL as temperature rises?
  19. butlen

    CH4 Explosive Limits

    Does anybody know the upper and lower explosive limits of methane at elevated pressures? I am working with mines gas which is an air+methane mix. I know that the LEL and HEL are 5-15% at atmospheric pressure, but I also know that as the gas is compressed the higher explosive limit rises.

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