[Gasification] questions for Tom Reed on stratified downdraft parameters

[Jeff Davis]

Hi Ken,

Don’t forget to include your exhaust gases into your calculations.


Jeff



> Jeff n all, Hi!
>                     I think that you have got your thermodynamics all
> wrong.
> The major heat load of hot gas is in the
> latent heat of vapourisation of the moisture.    It takes a lot of heat to
> boil water into steam and when steam condenses
> back into water it gives back that heat. All that happens at 100oC. Will
> an
> Icyball  run at 100oC?
> To cool gas at  say 500oC down to 200oC doesn't take much effort, and that
> means that it won't give up much energy either.
> Too old and too lazy to do the maths on that but check it out.  Don't take
> it that I am a downer on your ideas. Keep thinking, but
> this is supposed to save you a lot of effort in experimentation.  Cheers
> Ken
> C.
>
>
> ----- Original Message -----
> From: "Jeff Davis" <jeff0124 at velocity.net>
> To: <gasification at listserv.repp.org>
> Sent: Wednesday, April 18, 2007 9:27 AM
> Subject: Re: [Gasification] questions for Tom Reed on stratified downdraft
> parameters
>
>
>> Dear Tom,
>>
>> It's the heat that the IcyBall would absorb, in order to recharge it's
>> self. Like a heat absorbtion fridge. We can use the waste heat in the
>> gas
>> outlet to power an absorbtion fridge system. Next the system can cool
>> the
>> gas.
>>
>>
>>
>> Jeff
>>
>>
>>
>>> Dear Jeff:
>>>
>>> Not my field of expertise, but I doubt if any of the gases in producer
>>> gas would be absorbed in the icy ball cycle...  Just intuition.
>>>
>>> TOM REED
>>> ------------------------------------------------------------------------
>>>
>>> Jeff Davis wrote:
>>>> Dear Tom & All,
>>>>
>>>>
>>>>
>>>> I?ve considered using an automotive A/C unit to cool the gases just
>>>> before
>>>> the engine. I would think that this would remove a sizeable amount of
>>>> the
>>>> moisture from the gas.
>>>>
>>>> Now with the discovery of the IcyBall waste heat from the gasifier,
>>>> and
>>>> or
>>>> engine, could possibly be employed to cool the gas. In a simple batch
>>>> mode
>>>> you would have two IcyBalls, one being recharged via the waste heat
>>>> and
>>>> the second cooling the gas. Of course they would require manual
>>>> exchange.
>>>> Possible a re-circulating absorption cooler could be designed for this
>>>> task?
>>>>
>>>>
>>>> Jeff
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Tom wrote:
>>>>
>>>>> The efficiency and power of engines depends in part on the
>>>>> temperature
>>>>> of the intake mixture, and since we have gases, it would be tempting
>>>>> to
>>>>> have the lowest possible input temperature to the engine.  However,
>>>>> as
>>>>> you point out, paper filters and baghouses rapidly collect the fog
>>>>> and
>>>>> can generate too high a pressure drop.
>>>>> The easiest solution is to control your input air to 60 or 70C,
>>>>> depending on input fuel moisture and accept the small loss in power
>>>>> (make up with turbo charger?).
>>>>>
>>>>> Another solution could be to cool the gas to 10C (if you have a cold
>>>>> river nearby), drop out the fog, then reheat to 15 C to keep the
>>>>> filters
>>>>> dry.
>>>>>
>>>>> Good subject for discussion...
>>>>>
>>>>> TOM REED               BEF
>>>>> ------------------------------------------------------------------------
>>>>>
>>>>> Jeff Davis wrote:
>>>>>
>>>>>> Jim wrote:
>>>>>>
>>>>>>
>>>>>>> 6. filters:
>>>>>>> i am finding dry filters for secondary particulate filtering to not
>>>>>>> stay
>>>>>>> very dry, and generally become rather useless very quickly.  or
>>>>>>> rather,
>>>>>>> they get wet and then require huge vacuum to pull through them.  i
>>>>>>> am
>>>>>>> using
>>>>>>> shop vac paper/synthetic filters.  i am using them after a giant
>>>>>>> cooler/radiator and the gas going into the filter is very cool.  i
>>>>>>> think
>>>>>>> about 80-90deg.  i realize i could reheat partially before the
>>>>>>> filter
>>>>>>> to
>>>>>>> prevent this problem, but such isn't very attractive.  so from the
>>>>>>> experience of others out there, are dry "paper" filters generally
>>>>>>> unreasonable on gasifiers for condensate reasons?  do dry filters
>>>>>>> usually
>>>>>>> end up as some sort of sawdust, coffee or other granular filter
>>>>>>> media?
>>>>>>> are
>>>>>>> others finding the "wisdom" of wet filters after the failure of dry
>>>>>>> ones?
>>>>>>>
>>>>>>>
>>>>>> Dear Jim,
>>>>>>
>>>>>>
>>>>>> Yes, dew point is a big issue with dry filters.
>>>>>>
>>>>>> You might want to give composted horse dung a try.
>>>>>>
>>>>>> Better yet, moss. It keeps it's spongyness well.
>>>>>>
>>>>>>
>>>>>>
>>>>>> Jeff
>>>>>>
>>>>
>>>>
>>>>


-- 
Jeff Davis

Some where 20 miles south of Lake Erie, USA