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fluidized bed technology Answered

im currently working this one in my master's degree.. i let you know about my findings when i'll finish this.. as of now, i'm open to any suggestions or comments.. also, i need more references, materials and books, even journals that would deepen my understanding on this research..


What kind of waste were you planning on using? It seems pretty feaible to have a massive fan and gravity fed hoppers as a means of fuelling a large static furnace, if you got a good mix with the material you could burn extremely hot and extremely clean...

i will be using common waste here in our locality.. since we're rice eaters here.. i'm planning to use rice hulls..

That sounds like a pretty good material to use, if they're well dried they'd be usable as is, an old blower fan for factory ventilation would probably be usable if you ran it on a shaft and put the motor out of the heat...

yeah.. even it has as much as 40 - 50% moisture content, fluidized bed combustor can still burn it, according to some literatures on other waste.. but of course the combustion efficiency is not that good..

I was thinking more in terms of the dynamics, they'd burn better for sure but they'd also move better dry, rather than having to be ground up any... The only issue about them is you may need to have a pilot fire to keep things going, I'm not sure it depends on how well the husks burn...

yeah.. that might also another option.. but i think there will be some sort of pre-burner for the fluidizing gas, so that it will be heated up to a higher temperature in such a way that it will reach the ignition temperature of the rice hulls..

Maybe a starter burner would be needed but you could reroute some of the gas after it's reached sustainable temperatures to save the extra complexity, if it's planned to be a constantly running machine then a little extra awkwardness in starting would be acceptable...

yeah that's right.. i was out of town again.. im back now.. kip in touch bro.. i might have some questions for you soon..

Ask away, I'm planning a few experiments with this kind of stuff...

wow that's nice.. myb we can exchange some ideas and thoughts soon..

Cool, I'm planning some very small scale versions to start with though...

ok2x.. that's nice.. u can refer to esnips.com to have some literature f u want to.. theoretical background.. etc..

We'll see, I'll have a go first, so far following standard theory has failed me, it's why my cakes don't work out nice... I'll probably get a working something soon...

ok.. goodluck then.. i just have to wait for the materials, especially for the equipments after i'll defend this to the panel.. so it would take me longer.. good for you, you might have almost everything you need.. what waste are you planning to use as fuel by d way?

for now I'm planning on picking up a bag of sawdust as a test medium since the joinery dept. is happy to hand it over... I can get really fine stuff aswell, still need to get a higher speed fan system, most I've found so far can't put enough motion in to it...

. Wood has a lot of "tarry" materials in it (eg, creosote ). If these are allowed to cool, they will condense and plug things up. Not a big problem as long as you are aware of it and don't allow the gases to cool too soon.
. Depending on the depth and density of your bed, you more than likely need fairly high pressure and flow to actually fluidize the bed. Spargers will help distribute the air more evenly (and increase the need for pressure).
. One big problem with fluidized beds is channeling, where the air follows paths through the media and is not evenly distributed. Wood loves to clump, so you may need a mechanical stirrer/vibrator.

One nice thing is I can avoid some issues by choosing my source from many things including tiny spirals left from the planer... I'll only be using them as a testing ground anyway, my main aim is to have something that works in the same principle but probably wont be that close to a normal fulidized bed since I don't have those materials...

. I helped do some of the electrical design on a rice hull burner near Kuala Lumpur and a bagasse (sugar cane waste) burner in Columbia but neither uses a fluidized bed. I can't divulge any details, due to non-disclosure agreements, but may be able to answer some general questions.

thnx.. just kip in touch.. ill be asking some questions soon.. i was out for 1 week.. had some conection problems here in out city..

. I was an Instrument Tech/Electrician at a hazmat incinerator. No hands-on experience with fludized beds, but I read quite a bit about it and have seen some process diagrams. This was 10+ years ago, so any info I have is probably out-of-date. . Check some of the HazMat-related (and other industries that might use fluidized bed incinerators) trade magazines. The ads can give you an idea of what's going on and there are usually some practical articles. I'll bet that most of the ppl that write articles for those publications would love to get an e-mail from an interested reader.

i already visited the hazmatmag.com.. i hop they will respond to my e-mail.. i just want to ask you, even your not exposed to fluidized bed, how are the products of combustion treated? i mean technically speaking..

. We fed the solid material into rotary kilns in pyrolysis. Gases were sent through cyclonic separators to the main furnace (2000oF+) and ash was landfilled. Liquids were injected into the kilns or main furnace. If material was low BTU, natural gas was used to keep the temperatures up. Gases from the main furnace (primarily HCl and CO2 ) were wet scrubbed with Ca(OH)2 (lime).
. Primary driver for the system was a HUGE steam jet. Boilers were fired with high BTU waste.

ic.. i was out of town again.. that's why i wsnt able to rply.. anywya.. just kip in touch bro.. have some questions for you soon..

do you have a friend who is in contact with fluidized bed at that time you were employed in hazmat? if you have his contact please give me, an email add wud be a good start.. thnx..

. No. :( That was a loooonnnngggg time ago.

thnx bro.. i hop it will help.. i really wanted to be more specific and have a deeper knowledge of this.. i appreciate it..

You need to be more specific - are you looking at fluidised beds as a way of burning fuels in a furnace, coating things with powder, or something else?

yahh.. yah.. i'm more on the combustion technology part.. u know, sort of recycling waste materials which are low grade fuels.. instead of dumping this in a site, probably we can use this as fuel.. so u have some materials that wud help me?

i already did it, surfing the net, etc.. but i still dont have the enough sources.. there is this sciencedirect website but they try to sell their journals as much as 30 dollars.. it's quite expensive u know.. what i'm trying now is to look for websites that will let me atleast subscribe journals yearly..

In that case, I suggest you register at The Science Forums - there are some very knowledgeable people there.

Tell them I sent you, see what happens (I was one of the first members there).

ok thnx.. hope it will help. thnx kite.. i'll post soon about the update of my work..