Producing electricity from ... husks, sawdust

After more than 10 years of research, scientists from the Institute of Agricultural Engineering and Post-harvest Technology (CDNN & CNSTH) have initially completed the technology to produce electricity from agricultural by-products.

Now we don't have to burn away the sawdust anymore, but we can use it more effectively. With the successful study of this technology, in the future, waste types that seem to be removed (rice husks, corn cobs, bagasse .) will be able to produce a relatively large amount of electricity for humans. .

Waste can produce . into electricity

Currently, the major agricultural by-products in our country include rice husks, corn cobs, bagasse, sawdust, coconut shell . with a total output of millions of tons (if gathered). Prof. Dr. Pham Van Lang - Former Director of the Institute of Vocational Education and Training, chaired the research project, said: "Compared to the sources of large power exploitation from hydropower, thermoelectricity, power source from agricultural wastes though Not much, but if you take advantage of this waste source, it will help to reduce the environmental pollution, and can provide on-site electricity to rural areas, especially in remote areas . ".

Rice husk production alone can be collected in the Mekong Delta region up to 1.4-1.6 million tons. GS-TS. Pham Van Lang calculated, the total annual biomass waste output in our country could reach 8-11 million tons. Compared to producing electricity from coal, this production technology is much cheaper and economical, because using 2 to 4 kg of biomass will be equivalent to 1 kg of antracite coal (1,000 VND / kg), while the price of rice husk is only 5-10% of the price of coal.

In addition to the Mekong Delta, other areas such as the Central Highlands can also produce biomass waste from 0.3 to 0.5 million tons from coffee. The North West also brings 55,000-60,000 tons of sawdust from the exploitation and processing of wood. Especially waste from sugarcane factories, the country currently has 10-15% of the total bagasse is not used, causing environmental pollution and not being used. According to GS. Dr. Pham Van Lang, any kind of waste can be used as a fuel to produce electricity, the problem is that people have to be conscious of saving and collecting those wastes.

How is sawdust, rice husk . electricity?

After a lot of experiments, currently the Institute of Agricultural and Rural Development has built a technological line of FBC-CHP at Food Processing Factory No. 2 (Long An Food Corporation). This is a fairly modern line with 6 main components including: boilers and incinerators, steam turbines, generators, heat exchangers, low fluidized bed dryers, and dryers. The working principle of the chain is carried out through the following steps. Clean water from the water supply system is fed into the water treatment unit, then flows into the reservoir. From there, the pump system will supply water to the boiler of the fluidized bed combustion system.

Fuel is supplied to the boiler by a feeder. Fluidized bed furnace works to create a high-pressure steam supply, with a water flow of 2.500kg / hour and pulling a rotary turbine generator to generate voltage, supplying power plants or dryers . This voltage reaches 220 / 380V, the capacity can reach 50kW. Not only can electricity be produced, this line can also be used to dry agricultural products with a capacity of about 8 tons / hour because the heat generated in this process is very large.

Although the cost of producing electricity from this technology is higher than that of hydroelectricity (costing about US $ 1,500 / MW, but according to the evaluation of scientists, the price is still much cheaper than the sources of raw materials. The agar (about 10-30%), said Prof. Pham Van Lang: "So far, the Institute has built 7 kilns and made heat in the provinces of Long An, Kien Giang, Ho Chi Minh City, Gia Lai. . However, this technology is still in the process of research, if you want to expand it, it is necessary to have the help of the State and businesses to be able to build these lines ".

To produce 1kWh of electricity using this material source, it takes about 3-4kg of biomass waste. Thus, each year the country can also produce 3.8-4 million kWh of electricity and the ability to heat can also reach 11-12 million kWt.