[Gasification] Blue Water gas - Back to the future?

[Thomas Reed]

Dear Das and All:

"Those who do not study history are bound to repeat its mistakes."  
(Santayana) or bound to have to reinvent the better parts.  For >150 
years humans enjoyed the comforts of manufactured gas before methane 
displaced it.  Now we may need to revive some of that technology. 

Synthesis gas (CO, H2 low CH4 and no N2) will be important for making 
methanol fuels, mixed alcohols, FT diesel and fertilizer from now on.  
The simplest process for making it is the "blue water gas" process in 
continuous use from 1850s to 1940s. We were discussing the production of 
"blue water gas" yesterday and I was ignorant of details.  I found the 
following at http://en.wikipedia.org/wiki/Town_gas: 


*"The problem of nitrogen dilution was overcome by the **blue water gas 
(BWG) process, developed in the 1850s by Sir William Siemens 
<http://en.wikipedia.org/wiki/Carl_Wilhelm_Siemens>. The incandescent 
fuel bed would be alternately blasted with air followed by steam. The 
air reactions during the blow cycle are exothermic, heating up the bed, 
while the steam reactions during the make cycle, are endothermic and 
cool down the bed. The products from the air cycle contain non-caloric 
nitrogen and are exhausted out the stack while the products of the steam 
cycle are kept as blue water gas. This gas is composed almost entirely 
of CO and H_2 , and burns with a pale blue flame similar to natural gas. 
BWG has a CV of 11 MJ/m^3 (300 Btu/ft^3 (std)).*

Because blue water gas lacked illuminants it would not burn with a 
luminous flame in a simple fishtail gas jet as existed prior to the 
discovery of the Welsbach mantle 
<http://en.wikipedia.org/wiki/Gas_mantle> in the 1890s. Various attempts 
were made to enrich BWG with illuminants from gas oil in the 1860s. Gas 
oil was the flammable waste product from kerosene refining, made from 
the lightest and most volatile fractions (tops) of crude oil.

In 1875 Thaddeus S. C. Lowe <http://en.wikipedia.org/wiki/Thaddeus_Lowe> 
invented the *carburetted water gas* process. This process 
revolutionized the manufactured gas industry and was the standard 
technology until the end of manufactured gas era. A CWG generating set 
consisted of three elements; a producer (generator), carburettor and a 
super heater connected in series with gas pipes and valves.

During a make run, steam would be passed through the generator to make 
blue water gas. From the generator the hot water gas would pass into the 
top of the carburetor where light petroleum oils would be injected into 
the gas stream. The light oils would be thermocracked as they came in 
contact with the white hot checkerwork firebricks inside the 
carburettor. The hot enriched gas would then flow into the superheater, 
where the gas would be further cracked by more hot fire bricks."

I'm not sure this is all correct and neither was the author at Wikipedia. 

A more general discussion of the "gaslight" era and plant cleanup can be 
found at http://www.heritageresearch.com/manufactured_gas_index.htm. 

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Is it possible that we could make even better synthesis gas (water gas) 
using the blue water gas process and densified biomass?

Comments?

TOM REED            BEF