Rice husk is the largest by-product in rice processing, accounting for about 20% of rice weight. According to the world annual rice output of 568 million tons, the annual rice husk output is about11360,000 tons.
The combustible content of rice husk is more than 70%, and the calorific value of rice husk is 12560- 15070 kj/kg, which is about half of that of standard coal. It is a convenient and cheap energy source, especially in rice mills, which can treat rice husk while obtaining energy.
Because rice husk is renewable as an energy source, it is more attractive. Application fuels such as oil, natural gas and coal are non-renewable energy. Considering this essence, FAO realized at the beginning of 197 1 that in the foreseeable future, the most practical use of rice husk is to provide energy as fuel.
Other uses of rice husk
1, soil improvement
Rice husk charcoal has great advantages in improving soil of seedlings, horticulture, fruit trees and vegetable gardens. Almost all the 15 trace elements necessary for rice fields exist in rice husk waste residue.
Although this kind of charcoal is not a fertilizer in nature, it helps to accelerate the growth and vigorous growth of crops. This kind of charcoal can make rice more delicious if it is properly matched. Because it can keep soil moisture, the yield can be increased by more than 20%. Japan and some countries in Mekong River basin cultivate rice seedlings and vegetable seedlings with rice husk charcoal in vegetable gardens.
2. Purification of water
American patent has carbonized rice husk products as filter media. Rice husk charcoal can be used as coagulant aid for treating polluted water source or wastewater.