https://fortress.wa.gov/ecy/publications/documents/1107017.pdf

This is the most popular area of research . How biochar could be effectively used as the most recalcitrant form of carbon with the residence time carbon to the tune of 100-150 years. Biochar is produced through anaerobic decomposition of any biological material called feedstock. The nature and properties biochar is hugely dependent upon pyrolysis temperature and type of feedstock...Just search this issue on google , you will flooded with literature on biochar..

thanks a lot sir

Biochar, like charcoal and char is produced from pyrolysis, the process of heating carbon rich material (animal or vegetable matter) in oxygen deprived conditions. As humans have been making charcoal for thousands of years there are many traditional ways to produce charcoal.

The a typical process for making biochar proceeds along the following steps,

Traditional pyrolysis processes include include old style pit and mound kilns through to the evolution of brick and metal kilns in the last 100 years. However traditional charcoal-making technologies are both energy inefficient (with limited capacity to capture and use heat or gas) and highly polluting. In addition, as the the use of charcoal as biochar, where the focus is on it's value to agricultural and Carbon Sequestration, the need to enhance biochar's values in the pyrolysis production process becomes critical.

Spurred by the realisations about biochar's potential to increase food production (terra preta nova) and sequester atmospheric carbon, engineers have been developing pyrolysis kilns that resolve the limitations of tradition charcoal kilns and produce a char that is ideally suited to application to the soil, biochar. These challenges, or features, of modern Pyrolysis kilns are as follows,

• Continuous feed of feedstock material to increase the amount of biochar that can be produced (traditional kilns used batch processing).
• Management of oxygen intakes and energy use to increase efficiency of kiln and increase biochar yield.
• Capture of pyrolysis process bi-products, including syn or bio gasses, heat and oils for other economic uses or re-use in the pyrolysis process.
• Ability to alter and enhance the physical properties of the biochar produced to increase biochar surface area, biochar pore size and biochar stability (i.e. by varing kiln heat, processing time, pressure, etc...)
• Ability to process various feedstock materials into biochar.

These new pyrolysis technologies are evolving and different approaches to making biochar are being used and experimented with. 

You can find more information here (from Page 127):

https://books.google.com.ec/books?hl=en&lr=&id=iqrksC-PT1kC&oi=fnd&pg=PA127&dq=biochar+production&ots=FObFnG5Xwq&sig=2u1zGIANHbCuVM8LkPjnOwP-zoM#v=onepage&q=biochar%20production&f=false

Biochar is made using a process called pyrolysis. ... Pyrolysis involves placing the biomass into a special oven before heating in the presence of little or no oxygen. The result is a stable solid material rich in carbon content that can effectively capture carbon and lock the carbon into the soil.

Dear Drlatief Ahmad , I see nice and interesting responses from Dr. Anoop Kumar Srivastava, Ali Alhayany and Mushtaq Ahmad.

Application of biochar for soil amendment is being practiced since over 2,000 years by converting agricultural waste into a soil due to the reasons that it can hold carbon, boost food security, and increase soil biodiversity, and discourage deforestation. The process creates a fine-grained, highly porous charcoal that helps soils retain nutrients and water. Biochar can be an important tool to increase food security and cropland diversity in areas with severely depleted soils, scarce organic resources, and inadequate water and chemical fertilizer supplies. Biochar also improves water quality and quantity by increasing soil retention of nutrients and agrochemicals for plant and crop utilization. More nutrients stay in the soil instead of leaching into groundwater and causing pollution.

I have found interesting documents to help you for your further readings and please take your time and enjoy reading.

http://www.biochar-international.org/technology/production

Thank you so much for invitation, but this topic is out of my research domain.

Regards,

Emad

Here attached is a ppt. presentation about small-scale biochar making that may be easily replicated. I hope the document helps to answer your question.

Please have a look at these RG links and PDF attachments.

Chapter Chapter 2- Biochar: An Overview on its Production, Propertie...

Article Production and characterization of biochars from agricultura...

Article Effect of process parameters on production of biochar from b...

Article Recent developments on algal biochar production and characterization

https://www.researchgate.net/publication/258068939_Biochar_Production_Technology_for_Conversion_of_Cotton_Stalk_Bioresidue_into_Biochar_and_its_Characterization_for_Soil_Amendment_Qualities

Dear Dr. Latif thanks for highlight the this issue. Biochar is produced by heating biomass in the total or partial absence of oxygen. Pyrolysis is the most common technology employed to produce biochar, and also occurs in the early stages of the combustion and gasification processes. Besides biochar, bio-oil and gas can be collected from modern pyrolysers. These could be refined to a range of chemicals and/or used as sources of renewable energy if derived from sustainably produced biomass.

For more details go through this link-

http://biochar.international/the-biochar-opportunity/biochar-production-and-by-products/