3 replies to this topic

[Naushad]

Dear Members
can anyone please guide me or send me some detailed literature on the methods/process/equipment details on the coal gasification technology. can we have a pipeline grade natural gas by virtue of this technology to augment existing natural gas T&D network

Regards
Naushad

[Dazzler]

Hi Naushad

Yes - one of the possible products for coal gasification processes can be SNG (Synthetic Natural Gas).

Overall a typcial process would be: coal gasification - gas conditioning - acid gas removal - methanation - purification - compression - odourising.

Coal gasification licensors are Uhde, Siemens, Shell, Texaco. There may be others.


Dazzler

[Naushad]

Thanks Dazzler

can you please suggest me the source for the technical literature as i have to prepare the feasibility report.

[kkala]

can anyone please guide me or send me some detailed literature on the methods/process/equipment details on the coal gasification technology. can we have a pipeline grade natural gas by virtue of this technology to augment existing natural gas T&D network

Walker, Lewis, McAdams, Gilliland in "Principles of Chemical Engineering" (MgGraw-Hill, 1938) devote a whole chapter to "Gas Producers".
Wilson and Wells in "Coal, coke and coal chemicals" (MgGraw-Hill, 1950) devote a whole chapter to "Coal carbonization for gas manufacture".
My impression is that equipment have been lighter and less bulky since that time, even though principles have not changed. I have seen gasifiers to burn lignite in Ptolemais (Greece) in 1969 (as a student), following Koppers - Todjek (spelling ?) process. Coal gasification was the heart of the Plant, but there were numerous other units, similar to Dazzler's description: combustion gas purification with water sprays, H2S (and other S compounds) removal through amines, shift conversion CO+H2Og -- CO2+H2 (catalyst Fe2O3), CO2 separation through introducing CO2+H2 to an water tower under pressure, final purification of H2 to be suitable for NH3 production (using soda? etc). It seemed that units depended on the specification of the coal to be gasified.
Synthetic gas can be produced instead of H2 (see also wekepedia on it), actually this was planned by Ptolemais Industry before its shut down.
Known gasifiers were Lurgi, Koppers, Winkler (a bit later). British Gas was recently heard of.
Gasifiers should develop temperatures low enough to avoid melting of resulting ash (which would create heavy scales). In "late" Ptolemais plant,this was checked in the laboratory before the batch of lignite was burnt. You could see lignite powder flowing into gasifier for incomplete burning. As told, there was a critical feed "velocity", below which flame could travel back to the feeding lignite, and this had occurred (destruction prevented by PSV? - I am not sure of it). The Chemical Engineers of that Plant had a thick book on coal gasification, but there were a lot of other units treating the combustion gas. Waste water from gas purification was a complex unit, since many harmful substances were created from lignite burning. Resulting CO2 was separated from water at (almost) atmospheric pressure and sent to atmosphere (some thoughts of using it for urea synthesis were not realized).
You can find numerous books on carbon gasification (e.g. in www.bookfinder.com) and also information in WWW.
Probably above gives an introductory idea of the subject and the extended search needed for it.

Edited by kkala, 06 March 2010 - 02:13 PM.