[Gasification] eliminating carbon monoxide from coal gas

Jeff Davis jeffdavis0124 at gmail.com
Mon Apr 13 10:59:06 MDT 2015


Hi Henri,

I was replying to another post but coal or charcoal gasification will not
sustain reaction temp with only steam. Town gas had two reactors one being
air blown and the other steam blown. When the steamed reactor cooled they
would toggle back and forth. That's in regards to steam and air blowing not
any metal oxide methods.

But if the steam is hot enough maybe it will work as you stated below. Not
sure if that is within Anand's safety zone.

Gotta go,

Jeff





______________________________________________
"Once an owner has got used to charcoal gas he will never revert to the
more expensive fuels", Geo Bray
On Apr 13, 2015 12:47 PM, "Henri" <c_hnaths at telusplanet.net> wrote:

> Hi Jeff
> The reaction , hence the headline of the discussion, I am referring to is
> the elimination of Carbon monoxide.
> CO + H2O <=>CO2+H2. That reaction alone is exothermic. Favourable at low
> temperatures (t<200c)
> I assume you are referring to a charcoal Gasifier. If that be the case,
> are there not combustible by products from the charcoaling that can be
> oxidized to maintain the 900c heat needed to gasify the charcoal on steam
> alone. Because aparently superheated steam plus a char bed of 930c will
> gasify charcoal and yes *that*
>
>
>
> Quoting wiki
> Temperature dependenceEdit
> <http://en.m.wikipedia.org/wiki/Water-gas_shift_reaction#/editor/6>
>
>
> The water gas shift reaction is a moderately exothermic
> <http://en.m.wikipedia.org/wiki/Exothermic_reaction>reversible reaction.
> Therefore with increasing temperature the reaction rate increases but the
> conversion of reactants to products becomes less favorable.[6]
> <http://en.m.wikipedia.org/wiki/Water-gas_shift_reaction#cite_note-6> Due
> to its exothermic nature, high carbon monoxide conversion is
> thermodynamically
> <http://en.m.wikipedia.org/wiki/Thermodynamic_versus_kinetic_reaction_control> favored
> at low temperatures. Despite the thermodynamic favorability at low
> temperatures, the reaction is kinetically
> <http://en.m.wikipedia.org/wiki/Thermodynamic_versus_kinetic_reaction_control> favored
> at high temperatures. The water-gas shift reaction is sensitive to
> temperature
> <http://en.m.wikipedia.org/wiki/Chemical_equilibrium#Effect_of_temperature>,
> with the tendency to shift towards reactants as temperature increases due
> to Le Chatelier's principle
> <http://en.m.wikipedia.org/wiki/Le_Chatelier%27s_principle>. Over the
> temperature range 600 – 2000 K, the logarithm of the equilibrium constant
> for the WGSR is given by the following equation:[3]
> <http://en.m.wikipedia.org/wiki/Water-gas_shift_reaction#cite_note-Callaghan-3>
>
> [image: \log_{10} K_\mathrm{eq} = -2.4198 + 0.0003855T + \frac{2180.6}{T}]
>
>
> On Apr 13, 2015, at 9:05 AM, Jeff Davis <jeffdavis0124 at gmail.com> wrote:
>
> If the gasifier is air blown with some steam added the reaction will
> remain exothermic. If the gasifier is brought up to temp with air and then
> switched to steam blown then the reaction will be endothermic on pure steam
> and will need to be toggled back to air blown hence town gas.
>
> Jeff
>
>
> ______________________________________________
> "Once an owner has got used to charcoal gas he will never revert to the
> more expensive fuels", Geo Bray
> On Apr 12, 2015 9:37 PM, "Viswanathan KS" <viswanathanks at gmail.com> wrote:
>
>> Dr Karve wrote
>> Quote
>> --------. When hot charcoal is treated with steam, it produces coal
>> gas, consisting of a mixture of carbon monoxide and hydrogen. We have
>> used this reaction in an experimental stove, in which the coal gas is
>> used as fuel.   Can anybody suggest a simple method of removing carbon
>> monoxide from coal gas?
>> Unquote
>>
>> Is this reaction sustainable or will the charcoal fire get extinguished
>> due to prolonged passage of steam?
>>
>> The answer to this question should determine the continuation of the
>> discussion.
>>
>> On Mon, Apr 13, 2015 at 6:54 AM, Henri Naths <c_hnaths at telusplanet.net>
>> wrote:
>>
>>> Hello Anand
>>>
>>> Some of  the CO can be removed using the water gas reaction. This well
>>> known stoichiometry of the water the water-gas shift reaction is : co+h20
>>> <=>h2+co2+heat ( exothermic)
>>>
>>> In an efficient heat integrated scheme , the heat of the reaction can be
>>> recovered as superheated high pressure steam.
>>>
>>> H.
>>>
>>>
>>>
>>>
>>>
>>> On Apr 11, 2015, at 9:14 PM, Anand Karve <adkarve at gmail.com> wrote:
>>>
>>> Coal gas as automotive fuel
>>> Agriculture, forests and urban centres  in India produce annually
>>> about 1000 million tons of combustible waste biomass. Its energy
>>> content is almost 3 times as much as the petroleum that we currently
>>> use in our country.  Samuchit Enviro Tech developed a simple and
>>> nonpolluting technology for converting combustible biomass into
>>> charcoal. When hot charcoal is treated with steam, it produces coal
>>> gas, consisting of a mixture of carbon monoxide and hydrogen. We have
>>> used this reaction in an experimental stove, in which the coal gas is
>>> used as fuel.   Can anybody suggest a simple method of removing carbon
>>> monoxide from coal gas?
>>> Yours
>>> A.D.Karve
>>>
>>> ***
>>> Dr. A.D. Karve
>>>
>>> Chairman, Samuchit Enviro Tech Pvt Ltd (www.samuchit.com)
>>>
>>> Trustee & Founder President, Appropriate Rural Technology Institute
>>> (ARTI)
>>>
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