4 replies to this topic

[chemengisfun]

Hi,

I am trying to get an estimate on the amount of steam that can be generated in the jacket of the gasifier. Is there any heuristics available, such as % of heat of reaction/% heat loss from gasification is used for steam generation? I got a flowsheet simulation giving the exothermic heat duties from gasification.(I don't have any info on heat transfer coefficient etc). Many Thanks

[pavanayi]

chemengisfun,


Are you doing a conceptual study/feasibility study?
How detailed/accurate are you expecting to do the calculation?

Edited by pavanayi, 29 April 2011 - 02:56 PM.

[Art Montemayor]

chemengisfun:

I believe pavanayi's questions are very justified. Installing a jacket on a (coal?) gasifier is a serious decision. Unless you are dealing with a licensed process, I wouldn't normally attempt to do it.

The main function of a coal gasifier is to gasify. In that respect it functions as a reactor - but at very high temperatures - conditions that are taxing on the materials of construction. That is why you normally will find heat recovery downstream of a gasifier - in a heat recovery unit that is designed specifically for that purpose.

Can you please furnish some basic data of what is being proposed and a complete explanation?

[chemengisfun]

I am doing a conceptual study on an IGCC plant. I would only need a crude estimate of the steam generation from the jacket. I am using ASPEN Plus for my simulation, and I've got ~750 MW of exothermic heat from the gasifier (with coal feed of 2000 t/d), using Gibbs free energy minimization method. I don't think all of the heat can be utilised into the jacket, therefore I wish to know how to estimate this. I would be very grateful if any reference/literature can be provided.

Many thanks for your help.

[pavanayi]

chemengisfun,


For a basic conceptual study stage, I would probably assume a 85% total recovery potential to the nett recoverable heat (heat generated - heat lost along with exhaust gases) with an efficient heat recovery network. This nett heat will have to be used for generation and superheating of steam. Then apply a 30% factor for power generation. For a 2000TPD plant, I would estimate (out of my head) a nett power generation (power generated - power used within the process itslef) from steam at around 120-140MW.

If you want a better calculation, you would want to contact vendors. They will be able to quickly tell you a order of magnitude cost estimate as well as the steam generation.

As earlier said, I would not seriously think about a jacket around the gasifier. There are more efficient designs.

Edited by pavanayi, 01 May 2011 - 07:20 AM.