Archive for the ‘biochar production’ Category

Is there enough rice husk to make biochar?

November 17, 2010

As a follow on from the previous post, as mentioned many mills have piles of rice husk left from their activities, which is not being used at present.

Discussions with Dr Tan Boun Suy from the Apsara Authority, led us to consider the following question – if biochar is to be promoted as a useful soil amendment (for example at 20t/ha application for rice fields), is there enough?

Assumptions (for a very rough back of envelope calculation!)
– 2 harvests per year of rice at 1t/ha paddy produced per harvest
– 20% of paddy is husk
– 1/3 conversion rate of husk to biochar

2t/ha paddy produced, 0.4 t/ha husk, 0.13t/ha biochar per year.
Therefore in 150 years, enough biochar would be produced for a 20t/ha application rate.

Of course if biochar can increase harvest, then this would lead to more biochar availability!!

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Installing a gasification unit

October 25, 2010

A visit was taken to the rice mill at the Nagathom fund (some of their out growers are also taking part in the biochar trials), where SME renewables are installing a gasification unit.

Reactor, ready for installation - Siem Reap, Cambodia

POMs recovered…

October 22, 2010

Today the POMs (passive sampling strips), were removed from the soil and from the area surrounding the gasifier. They were left in-situ for 4 months, and will undergo analysis in the next few weeks.

POMs were left in this run-off pond from the gasifier (wet discharge system)

So what is the importance of biomass energy?

July 21, 2010

I’ve recently listened to the webinar Solar Fuel – Natural and Artificial Photosynthesis by James Barber, Imperial college organised by UKERC (UK Energy Research Council) National Energy Research Network (NERN) / EG&S (Energy Generation and Supply) KTN (Knowledge Transfer Network). It was a fascinating look at artificial photosynthesis (Ps.), but here are a few points which were inspired by the comments on natural Ps. and it’s contribution to the energy question.

– Scale of current use

In terms of global energy consumption, out of 14 TW of energy currently, 1.21 TW is from biomass, 4.52 is oil and 0.286 is renewables. In terms of number of people using biomass energy, just one example, for cooking and heating, over a third of humanity, 2.4 billion people burn biomass (Warwick & Doig 2004)

– Potential for sequestering C

Almost half of the C which we burn goes into the atmosphere, and half is sequestered through Ps – a photochemical process which converts hydrogen and oxygen and carbon dioxide from the atmosphere into biomass. Although the global average conversion of light to energy is 0.2%, the maximum efficiency is 4.5%.
Where biochar is a product from energy generation from biomass, this conversion of C can be subsequently stored in soils.

Conversely, burning of biomass leads to black carbon (not biochar) particulate matter which contributes to the global warming effect, although this warming effect may be less than that of black carbon from industrial fossil fuel burning (Grieshop et al 2009).

– Large scale production

Bioenergy crops are widespread, although the availability of land for expansion is a question. But there is potential for energy production in units which can utilise waste products including rice husks, and also number of recent developments in smaller scale technologies which can also burn rice husks. This is known as a second generation biofuel, and does not compete with food production.


Grieshop, A.P., Reynolds, C.C.O., Kandlikar, M. and Dowlatabadi, H. 2009. A black-carbon mitigation wedge. Nature Geoscience. Vol 2. August 2009.

Warwick, H. & Doig, A. (2004). Smoke – the Killer in the Kitchen. Indoor Air Pollution in Developing Countries. Practical Action, ITDG.

POM deployment in biochar and waste water of gasifier

June 2, 2010

POM was deployed in two areas where waste water from the gasifier ends up.

The gasification unit is EAP SOPHAT ice factory in Kralanh town, Siem Reap Province, which is the source of biochar from the plot and pot trials in Cambodia.

POM deployment 02.06.10 EAP SOPHAT gasification unit biochar and waste water

Gasification unit

February 13, 2010

A SME gasification unit at EAP Sophat ice factory, in Kralanh District Town.