Carbonisation of rice straw and its implications for energy development

The efficiency for carbonization (percentage of carbon stored in charcoal) is still low in the current method, however direct heating process yields better char yield of 17% as compared to indirect heating with 15% process. Carbon and energy balance was also carried out and the results were compared for the direct and indirect process. Burning by indirect draft gives better results like more char, faster process. Direct draft gives less char, but higher quality (higher C and H2). Also a lot of straw is left unburnt in the direct draft kiln, because of bad temperature distribution and flow inside. The kiln design might be more suitable for indirect draft rather than direct draft. Both methods still give rice straw charcoal that has low calorific value with an output char LHV of 4337 kcal/kg as compared to fresh rice straw of 3412 kcal/kg.

In the direct heating method output char % is enriched to 45% with a still unburnt rice straw left out as compared to indirect heating method with carbon enrichment of 39%. There is a loss of 13% of carbon through the ash in the both the methods. The carbon content in the condensate is in the order of 18.5% for the indirect process as compared to 13.9% in the direct process due to less exhaust and carbon enrichment inside the kiln. There is a loss of 43% of carbon in the exhaust from indirect heating process as compared to direct heating process which is reduced to 26%. The energy balance predicts a heat loss of 14% in exhaust gases.


INTRODUCTION

1.1 Rational

Rice straw is left as a residue after rice harvesting; which is often Thailand has … square kilometres of rice farm and most farmers in Thailand simply get rid off it by open burning in the field. Open burning causes many problems such as in owns influence on soil nutrition, soil moisture, pollution, and being flammable to nearby structures. Charcoal making process is being practiced since ages and different types of biomasses are used as raw materials for producing charcoal. Rice straw Although there is rice straw produced in the Rayong and Chonburi provinces and , it is currently being burnt in the field or minimized application as fodder for animal.
To provide a solution for the rice framers in order not to burn and apply back onto the soil to enhance the soil quality and as a conditioner, the traditional charcoal making procedure will be reviewed and experiments would be conducted to evaluate the feasibility of rice straw for charcoal making.



Rice straw is left as a residue after rice harvesting; Thailand has … square kilometres [BG1]of rice farm and most rice farmers in Thailand simply get rid of it by open burning in the field. Open burning causes many problems in owns soil nutrition, soil moisture, pollution, and being flammable to nearby structures.
Charcoal making process is being practiced since ages and different types of biomasses are used as raw materials for producing charcoal. Although there is rice straw produced in the province, it is currently being burnt in the field or minimized application as fodder for animal.
To provide a solution for the rice framers in order not to burn and apply back onto the soil to enhance the soil quality and as a conditioner. , tThe traditional charcoal making procedure will be reviewed and experiments would be conducted to evaluate the feasibility of rice straw for charcoal making.


1.2 Objectives

• To evaluate the carbonization technology using rice straw
• Energy analysis and emission analysis using for rice straw to char
• Detailed listing on the processing requirement for preparation rice straw and output[BG3]

1.3 Scope of Work

· Collection of rice straw for the batch operation
· Proximate and ultimate analysis of rice straw
· Processing required for rice straw to input into the kiln

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