[Gasification] Soot on tubes

[N. Selvakumar]

Dear Rex,

The penetration of tar and dust through the heat exchanger tube is the
function of time-temperature profile and radial temperature gradient
inaddition to the information of dust particle size distribution.  Low tar
content does not mean anything when you want to cool the gas. It is the
boiling point and group of tar species present in the tar content.  Milne et
al (1998) reports on Biomass Gasifiers Tars: Their Nature, Formation, and
Conversion.

About tar, more you drop the temperature of gas more the quantity of tar
produced in the gas.

If you want to generate low quality steam, by cooling the producer gases
temperature from say 400C. My answer/opinion is yes, provided if you
understood the system well.

With regards
Selvakumar

Zietsman, Rex wrote:
> Doug wrote:
>
> "Hi Rex,
>
> You Ask:
>> Please can you elaborate more on the soot formation in cooling gas
> down.           > While I knew that soot occurs, I got an undertone from
> your comment that it may > coat the cooling heat exchanger. Has this
> been your experience?
>
> Remember that I said it depends on where the exchanger is located in the
> system. Until the gas is stripped of dust, it will coat the inside of
> any tubing.
>
>> If it does coat, what do you do to keep it from doing so or to get it
> off?
>
> You have to open them up and scrape the tubes, or have some type of
> mechanized scraper system. The rate of sooting depends on many factors,
> which is why designing these cooling systems is more than just
> calculations. For sure you will need to know what quality of gas you are
> going to cool, because if pyrolisis oils are present, nothing will stop
> the tubes fouling. Producer gas is a very challenging task master, and
> many normal design rules just do not apply.
>
> The alternative is wet scrubbers, or water sprays in the tubes, but then
> it becomes a liquid disposal problem.
>
> Regards,
> Doug Williams,
> Fluidyne"
>
> Doug,
>
> Does the dust and soot pack on in the tubes due to tar in the gas? What
> I am asking is, if the tar content is low, the dust and soot should be
> entrained and leave the heat exchanger?
>
> Rex
>
> _______________________________________________
> Gasification mailing list
> Gasification at listserv.repp.org
> http://listserv.repp.org/mailman/listinfo/gasification_listserv.repp.org
> http://gasifiers.bioenergylists.org
> http://info.bioenergylists.org
>


It is not the aptitude but the attitude that decides a persons altitude
_______________________________________________

With Regards
N. Selvakumar
Research Scholar
CESE
IIT Bombay
Powai,Mumbai
India 400 076