[Gasification] back to gasification

linvent at aol.com linvent at aol.com
Thu Jun 2 06:30:35 CDT 2011


With the exception that CO found in producer gas moderates the H2 combustion rate and moves the potential compression ratio way up above CH4 tolerable compression levels. There is also the question of whether taking the producer gas to methane has the economic benefit of doing so when you are then competing with natural gas which in the US is selling for $4/mmBTU. 
 
Sincerely,
Leland T. "Tom" Taylor
President
Thermogenics Inc. 




-----Original Message-----
From: Jim Leach <jleach at danatech.net>
To: 'Discussion of biomass pyrolysis and gasification' <gasification at lists.bioenergylists.org>
Sent: Wed, Jun 1, 2011 5:35 pm
Subject: Re: [Gasification] back to gasification

Thanks again Florian,
 
I do have a couple of comments.  You still have to cool the product gas down for the gas turbine, not because of the turbine, but because of the gas control valves.  They have temperature limits that cannot be exceeded, typically about 60C.  Also, there is an energy benefit to methanation for application to engines.  The benefit is that converting the H2 to CH4 will allow engines with higher BMEPs to be applied, and that means higher efficiency, and greater output for the same engine frame size.
 
Best Regards,
 
JAMES T. LEACH, P.E.
President
 
DANA TECHNOLOGIES, INC.
32242 Paseo Adelanto, Suite D
San Juan Capistrano, CA 92675
Ph 949-496-6516
Fx 949-496-8133
Mobile 949-933-6518
 

From: gasification-bounces at lists.bioenergylists.org [mailto:gasification-bounces at lists.bioenergylists.org] On Behalf Of Florian Nagel
Sent: Wednesday, June 01, 2011 4:07 PM
To: 'Discussion of biomass pyrolysis and gasification'
Subject: Re: [Gasification] back to gasification



Hi James
 
Regarding gas engines, you are right that cooling is a must from a thermodynamical perspective. Regarding gas turbines, a hot gas cleaning process would be very nice to have (excuse me mentioning gas turbines in the last sentence of the last comment…clearly doesn’t belong there…) because the turbines have the potential to stand high combustion temperatures. The according exhaust gas would be in turn very hot, which makes the use of this heat possible in a bottoming cycle. So, looking at a gasturbine combined cycle, high fuel gas temperature does make sense if you adjust the combustion temperature in a way that the gas turbine stands it and if you use the exhaust heat. However, this requires a hot gas cleaning process. At PSI, we operated high-temperature fuel cell  with producer gas that was cleaned in a hot gas cleaning system where the gas temperature never dropped below 500C. Thus, there are ways to remove tars, etc. at high temperature (Catalytic partial oxidation or high-temperature reforming steps). Anyways, I wouldn’t go so far and say that this technology is readily available ;o)
 
In any case, methanation is a great way to convert woody biomass into a more usable and storable form but I don’t quite see it in combination with gas engines. Just to expensive and without real efficiency benefit if you aim at electricity as end product.
 
Cheers
Florian
 
From: gasification-bounces at lists.bioenergylists.org [mailto:gasification-bounces at lists.bioenergylists.org] On Behalf Of Jim Leach
Sent: Wednesday, June 01, 2011 17:18
To: 'Discussion of biomass pyrolysis and gasification'
Subject: Re: [Gasification] back to gasification


 
Thanks Florian,
 
If one wants to burn the product gas in an engine or a gas turbine you have to cool and clean the gas anyway.  So dropping the temperature would be a part of the tar removal process and would occur anyway.  Adding water is not good because the product gas must be well below the dew point for the combustion device.  So it you put it in for methanation, you will have to take it out later. But what I was interested in was simply converting the H2 to CH4, because engines (including GT's) don't really like H2 (it burns too fast).  Reciprocating engines in particular, would much prefer a steady diet of CH4.  But I think I understand from your answer is that it is not worth it.  Unfortunately, an answer I was expecting.
 

JAMES T. LEACH, P.E.
President
 
DANA TECHNOLOGIES, INC.
32242 Paseo Adelanto, Suite D
San Juan Capistrano, CA 92675
Ph 949-496-6516
Fx 949-496-8133
Mobile 949-933-6518
 

 

From: gasification-bounces at lists.bioenergylists.org [mailto:gasification-bounces at lists.bioenergylists.org] On Behalf Of Florian Nagel
Sent: Wednesday, June 01, 2011 2:52 PM
To: 'Discussion of biomass pyrolysis and gasification'
Subject: Re: [Gasification] back to gasification
Hi James
 
I cant comment on the cost of the methanation step but I can comment on your idea regarding a methanation step as fuel upgrade in a gasification- and gas engine-based power plant. I did my thesis together with Jan at PSI working on the combination of high-temperature fuel cells with woody biomass gasifiers: http://e-collection.library.ethz.ch/view/eth:41553 . Hi Jan, I m still on that list as you see :D
 
Methanation is an exothermic process that yields the highest methane concentration in the product gas when kept around 400C process temperature. Hence, you ll first have to cool your syngas down to 400C. Depending on your gasifier type and syngas composition, you might get into carbon deposition problems (Boudouard reaction for example where 2 CO molecules decompose into carbon and carbon dioxide). You can overcome these problems by injecting steam into your syngas (which will cool it down at the same time..) which you will also need to increase your hydrogen atom content in a way that allows methanation. Then you can take it from there and produce methane.
 
Problem I see is that by introducing water into your fuel gas, you already lower its heating value. This results in a lower combustion temperature in your gas engine. Gas engines are limited by the Carnot efficiency rule that clearly states that the efficiency of a combustion engine increases with the difference between the temperature of the hot compressed combusted gas and the temperature of the expanded exhaust gas. Hence, the efficiency of a combustion engine running on humidized syngas should definitely be lower than running on unhumidified syngas. Next problem is, during the methanation you have to cool the reactor. Thus you are again reducing the energy content of your syngas or by that time synthetic methane (relative to the energy content of the initial feedstock). The energy you extract from the methanation process is in form of low-temperature heat (400C) which you can hardly use economically to produce electricity with a steam cycle. Once you have your synthetic methane gas mixture, you ll have to reduce the high water content of it to not run into above mentioned efficiency issues of the combustion engine. This can only be done by cooling the gas close to ambient temperature were the water simply condenses. Another point in the process were you extract energy at very very low temperature level. I would consider this energy as a complete loss. From there you can use the dried, cold synthetic methane in your engine and produce electricity.
 
To put it in numbers: Good gasification-gas engine plants reach efficiencies around 25 to 30% without bottoming-cycle (steam cycle to use exhaust heat). The methanation process has an efficiency around 65%. Together with a very high combustion engine efficiency of 42.5%, you end up with a maximum efficiency of a gasification-methanation-gas engine scheme of around 27.5%. However, with considerably higher equipment cost. I definitely recommend not to use a methanation step as fuel upgrading step but to use the syngas directly in your engine. In any case, the world totally changes if you aim at using high-temperature fuel cells, gas turbines or if you want to make the wood energy transportable and storable. The latter was the idea of the PSI methanation project given Switzerlands dependence on foreign gas imports.
 
Cheers
Florian 
 
From: gasification-bounces at lists.bioenergylists.org [mailto:gasification-bounces at lists.bioenergylists.org] On Behalf Of Jim Leach
Sent: Wednesday, June 01, 2011 15:51
To: 'Discussion of biomass pyrolysis and gasification'
Subject: Re: [Gasification] back to gasification


 
Jan,
I am curious what method you selected for tar removal. Also, was the methanation step expensive?  The methane would make a better engine fuel than the H2 and CO but I am concerned about the cost.
 
Best Regards,
 
 
 

JAMES T. LEACH, P.E.
President
 
DANA TECHNOLOGIES, INC.
32242 Paseo Adelanto, Suite D
San Juan Capistrano, CA 92675
Ph 949-496-6516
Fx 949-496-8133
Mobile 949-933-6518
 

 

From: gasification-bounces at lists.bioenergylists.org [mailto:gasification-bounces at lists.bioenergylists.org] On Behalf Of Jan Kopyscinski
Sent: Wednesday, June 01, 2011 1:13 PM
To: Discussion of biomass pyrolysis and gasification
Subject: Re: [Gasification] back to gasification
Hi Kevin,

I did my Phd thesis on this topic. You can find more information there:
http://e-collection.library.ethz.ch/view/eth:1059

or under www.bio-sng.com and www.biosng.com, http://www.biofuelstp.eu/bio-sng.html and on other pages.

In  a nut shell the process consits of:
1) low temperature steam gasification
2) gas cleaning (ash, tar, H2S, ...)
3) methanation = conversion of the syngas into methan (catalytic process, mostly Nickelcatalyst)
 CO + 3 H2 --> CH4 + H2O
 CO + H2O --> H2 + CO2

If you use a different catalyst you can go for higher hydrocarbon such as Fischer Tropsch Diesel, or Methanol, ....

4) Fuel upgrading = removal of H2O, CO2

We at the Paul Scherrer Institute in Switzerland (http://tpe.web.psi.ch/) investigated this process from wood to BioSNG in two scales for more than 1000h.

Regards

Jan
- Dr. sc. Jan KopyscinskiPostdoctoral fellowDepartment of Chemical and Petroleum EngineeringSchulich School of EngineeringUniversity of Calgary2500 University Drive NWCalgary, Alberta, Canada  T2N 1N4 Email: jan.kopyscinski at ucalgary.caPhone: 001 403 2109575 




Von: Kevin <kchisholm at ca.inter.net>
Gesendet: May 31, 2011 5:02:24 PM
An: "Discussion of biomass pyrolysis and gasification" <gasification at lists.bioenergylists.org>
Betreff: Re: [Gasification] back to gasification
Dear Jan

 

Very interesting!!

 

What steam temperature and pressure is required to gasify wood?

 

Once one has such gas, what sort processing is required to convert it to CH4? (That is, what temperatures, pressures, catalysts, etc)

 

Is there any way this can be done on a small scale?

 

Is there any way this process can be modified to produce methanol on a small scale? If so, this would be awesome... it would then yield a very portable liquid fuel.

 

Thanks!

 

Kevin

----- Original Message -----

From: Jan Kopyscinski

To: Discussion of biomass pyrolysis and gasification

Sent: Tuesday, May 31, 2011 11:30 AM

Subject: Re: [Gasification] back to gasification

 


Hi,

First of all, there are at least two different types of biofuel:
First Generation:  agricultural feedstock, which is converted by means of biochemical processes (i.e., digestion) --> Biogas
Second Generation: woody biomass that is converted via thermochemical converiosn into a producer or so-calles syngas (Gasification).
Thus, if your goal is to produce Methan or Natural Gas substite for a gas engine or transportation fuel you have different options. But you need to know what is your feedstock (dry , wet, digestable or not digestable such as wood):
If you have a rather dry feedstock you can go for steam gasifiaction (no air, means no Nitrogen). The produced syngas you can catalytilcally convert to CH4, CO2 and H2O. Prior to the methanation process you need to remove the sulphur since it is deactivating your catalyts. H2O and CO2 can then be removed. This process has been investiaget by the Paul Scherrer Institiute in Switzerland (www.psi.ch and www.bio-sng.com).
Removal of nitrogen is too expensive, thus you should avoid feeding it into your process. 2 vol% to max 5vol% N2 in the methan rich gas is acceptable.

Regards,

Jan

Von: "Pannirselvam P.V" <pannirbr at gmail.com>
Gesendet: May 31, 2011 12:46:54 PM
An: "Discussion of biomass pyrolysis and gasification" <gasification at lists.bioenergylists.org>
Betreff: Re: [Gasification] back to gasification

Dear A.D Karve  
 

      One of the project we have been studying  is based on the  IGT,Instuite  Gas technology patented process  called Biotherm , in which the  wood  gas or syngqs  can be passed into the biodigestor, in which  CO and  Hydrogen can  be converted into  methane ; the  NOX .COX, SOX removed via simple  known wet or  dry process using activated charcoal and  lime ; the methane is then compressed.The N  can be removed  as ammonia,as this can be very toxic to bio methane bacteria; Syngas obtained via pyrogas can reduce this N2 problem and complexity.Thus pyrogas technology  has more potential than  wood gas technology

 

  we are studying how to make this complex process into simple innovative process to  make possible charcoal and  methane economy which is practiced  in the developed country  in big scale  can be  made possible in developing village level technology too in small scale ,The project is yet in design stage to reduce CO2 to use as liquid  fertilizer too increasing the calorific valued the compressed biogas.

 

Yours truely

Pannirselvam

 

 
On Mon, May 30, 2011 at 11:01 PM, Anand Karve <adkarve at gmail.com> wrote:
Dear List,
We are already using, in India, wood gas made from agricultural waste
to run stationary internal combustion engines. But, for using it as
automobile fuel, it would have to be filled into cylinders, for which
the nitrogen in the wood gas would have to be removed in order to
reduce its bulk and to increase its calorfiic value. Does anybody have
a suggestion as to how this can be achieved?
Yours
A.D.Karve

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