Re: GAS-L: Batch loaded gasifiers - small ones

[Cordner Peacocke <cpeacocke@care.demon.co.uk>]

In answer to the question on:

''what does one do with the char?''

In some cases, the char is used for filtering any water from the process, 
as a gas filter media in the process, and it can be dried [if used for 
water filtration] and returned to the gasifier.  Some can be used for 
start-up, if you operate in batch mode and any excess does not have much 
value. A portion can be recycled back to the gasifier during operation, but 
not too much, otherwise excess ash in the gasifier can be a problem. This 
''recycling'' gradually concentrates the ash for disposal to landfill, use 
in aggregates, or returned to the land, but requires careful management.

If you are using rice husks, then the char, containing the ash (up to 20wt% 
in some cases in the starting material) is a major problem, as over 2-30wt% 
of your starting rice husks.  In China, this is their biggest problem, 
apart from the wastewater.  It is simply piled up and burnt.

Cordner Peacocke


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