After more than 10 years of research, scientists from the Institute of Agricultural and Post-Harvest Mechanization and Technology (CĐNN&CNSTH) have initially perfected the technology for generating electricity from various agricultural waste by-products.
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| Now we no longer have to burn sawdust, but can use it more beneficially. |
With the successful development of this technology, in the future, waste materials that seem useless (such as rice husks, corn cobs, sugarcane bagasse…) will be able to generate a relatively large amount of electricity for people.
Waste Can Be Converted… Into Electricity
Currently, the main agricultural by-products in our country include rice husks, corn cobs, sugarcane bagasse, sawdust, coconut shells… with a total production amounting to millions of tons (if collected). Prof. Dr. Pham Van Lang, former director of the CĐNN&CNSTH and head of the research project, stated: “Compared to large-scale electricity generation sources like hydropower and thermal power, electricity from agricultural waste may not be much. However, utilizing this waste can both help reduce environmental pollution and provide local electricity for rural areas, especially remote and mountainous regions…”.
Specifically, the amount of rice husks that can be collected in the Mekong Delta can reach 1.4-1.6 million tons. Prof. Dr. Pham Van Lang calculated that the total biomass waste production annually in our country can reach 8-11 million tons. Compared to coal-fired electricity generation, this production technology is much cheaper and more economical, as using 2-4 kg of biomass waste is equivalent to 1 kg of anthracite coal (priced at 1,000 VND/kg), while the price of rice husks is only 5-10% of the coal price.
Besides the Mekong Delta, other areas like the Central Highlands can also yield biomass waste ranging from 0.3-0.5 million tons from coffee plants. The Northwest region can provide up to 55,000-60,000 tons of sawdust from logging and wood processing. Particularly, waste from sugarcane mills currently sees about 10-15% of the total bagasse produced going unused, which not only causes environmental pollution but also goes to waste. According to Prof. Dr. Pham Van Lang, any type of waste can be used as fuel to generate electricity; the key issue is that people must be conscious about saving and collecting this waste.
How Are Sawdust and Rice Husks Converted Into Electricity?
After numerous experiments, the CĐNN&CNSTH has constructed an FBC-CHP technology line at the No. 2 Food Processing Enterprise (Long An Food Corporation). This is a fairly modern line with 6 main components including: boiler and combustion furnace, steam turbine, generator, heat exchange equipment, fluidized bed dryer, and low-temperature dryer. The working principle of the line is carried out through the following steps. Clean water from the water supply system is sent to the water treatment unit and then flows into the storage tank. From here, the pump system supplies water to the boiler of the fluidized bed combustion system.
The fuel is delivered to the boiler by a feeding system. The fluidized bed furnace operates to produce heat, generating high-pressure steam with a water flow rate of 2,500 kg/hour, which drives the turbine, turning the generator to produce electricity for the power plant or dryer. The electrical output can reach 220/380V, with a capacity of up to 50 kW. Not only does this line produce electricity, but it can also be used to dry agricultural products at a capacity of about 8 tons/hour due to the large amount of heat generated during this process.
Although the cost of producing electricity using this technology is higher than hydropower (with costs around 1,500 USD/MW), scientists evaluate that this price is still much cheaper compared to fossil fuel sources (about 10-30%). Prof. Dr. Pham Van Lang noted: “To date, the Institute has established 7 drying and heating furnaces in Long An, Kien Giang, Ho Chi Minh City, Gia Lai… However, this technology is still under research, and to expand further, support from the government and businesses is necessary to build these systems.”
To produce 1 kWh of electricity from this biomass source, approximately 3-4 kg of waste is needed. Thus, the country can produce 3.8-4 million kWh of electricity annually, with the thermal output potentially reaching 11-12 million kWt.
