5 replies to this topic

[curtin]

Hi,

I work at a large Alumina Refinery, and we are evaluating the use of Syngas as a supplement / alternative to our current natural gas supply. We currently use natural gas in our turbine generators and our Calciners.

I would particually like to know if anyone has had any experience with the inductrial use of syngas as a feed, or if they have used it as a cheep supplement for their natural gas supply. Any info on its use would be appreciated, as I have not had any experience with syngas to date.

FYI - the syngas we are looking at is being produced from a local coal reserve, with the main composition quoted as:
H2O - 0.3%
H2 - 22.2%
CO - 60.2%
CO2 - 7.2%
N2 - 9.8%

Thanks heaps,
Chad

[pawan]

I would rather prefer to use this valuable source for better value added products e.g. ammonia or methanol & downstream products.

In terms of fuel value it may be same ( I dont see any harm using it) but its got lot of value in terms of hydrogen availability the sysnthesis of which from natural gas itself is very costly.

Try to use natural gas for heating / fuel purpose and consider this syn gas for downstream products starting from a reactor.

[curtin]

Thanks pawan,

This particular stream will be an off gas from the production of ammonia. Hence the company is trying to offload this gas to us... if we can find a suitable use for it.

The HHV seems to be around 1/4 to 1/3 of our normal natural gas supply, but if the price is right we will use it where we can (gas is in short supply around here).

Hence the remote location is making it feasible for the supplier to offload this gas to us, rather then find some other more capital intensive way of selling it.

Apart from the extra volumetric flow rate required, we can not really see a reason why we shouldn't use it if the price is right.

[djack77494]

I see no reason not to use this gas as fuel. Of course, with its properties being so different from those of natural gas, you must expect to treat it very differently. I'd suspect that you'd have to go so far as to have a completely independent system at each spot where you want to use this fuel. By this I mean that you should treat it as an alternative fuel, with its own burners, controls, etc. - almost how you might configure (say) a boiler that could fire either fuel oil or fuel gas. Alternatively, if you expect the proportions of natural gas and syngas to remain in a fairly narrow range, it may be possible to design for a mixed fuel gas with considerable capital savings. You'd have to carefully evaluate the reliability of the mixed gas and have options for synthesizing it if one of the fuels is not available.
Good luck,
Doug

[imtiaz]

Hi Chad,
From the composition given, the systhesis gas will be of a lower calorific value than that of natural gas, so you can expect to be using much more for your heating requirements. Have you evaluated what quantity of syn gas you would require to provide the heating requirements if natural gas will no loger be used normally? Also, will this quantity be supplied in adequate amounts?
From the composition you should be able to used the syn gas.
From my experience in the methanol industry, we have used it in the reformer burners and cut back on the natural gas requirement with good results.

regards,
Imtiaz.

[Satyajit]

This syngas could be a good source of feed for ammonia , methanol, butanol plant.

As the H2 content is too low, it will be little difficult to upgrade this syngas for ammonia, methanol and butanol or sponge iron plant.

There are few thinks need to be considered for the feasibility of such projects.

1. syn gas price ( economical if it is available as low calorific valued fuel gas cost}

2. Presence of heavy metals, Impurities etc.

3. Volume of gas available and consistency of quality

4. Selection of technologies :

i. Shift converter >CO2 Removal> ammonia synthesis. ,
ii. CO2 Removal > Cold Box > Ammonia and Acetic Acid
iii. CO2 removal > Membrane Unit > Butanol manufacturing
iv. Methanol manufacturing

Alternatively it can be used in fuel; Based on experience I can say that it's not a good fuel to use in furnace and has following implications:

1. Furnace draft
2. Increase in flue gas Volume
3. Increase in fuel gas header pressure
4. Velocity of H2 is very high comparatively which may lead to flame impingement on tubes in the furance and tube failure subsequently.
5. Reduces available heat flux when replaced by natural Gas.

Hope this information is useful to you.

Good luck.

Satyajit