Turning agricultural waste into Vietnamese smokeless charcoal exports worth ten times more

To make use of agricultural waste from corn cobs while helping reduce environmental pollution, Moc Chau Xanh Energy Co., Ltd., based in Moc Chau District, Son La Province, has developed smokeless, odorless charcoal briquettes and biomass fuel sticks made from corn cobs.

According to Giang Minh Thai, Deputy Director of Moc Chau Xanh Energy Co., Ltd., Son La Province has the largest corn-growing area and the highest corn output in Vietnam. As a result, it generates a huge volume of corn cobs each year. Although fresh corn cobs can be returned to fields as organic matter, they take two to three years to decompose.

As a result, apart from a small portion used as fuel or as a growing medium for mushrooms, most corn cobs are discarded along roadsides or into rivers and streams. This contributes to environmental pollution.

Previously, Thai’s company had to purchase fuel for its manufacturing operations. Seeing the large amount of underutilized corn cobs, he and several friends came up with the idea of compressing them into charcoal. Their goal was to turn the waste into a valuable resource.

However, it took two years of research and experimentation before Thai and his team successfully developed a satisfactory product and put it into commercial production.

Recognizing the commercial potential of the product, Thai invested in a professional production line to make use of this agricultural by-product. In 2015, Moc Chau Xanh Energy Co., Ltd. was officially established, becoming the first company in Vietnam to produce activated charcoal from corn cobs.

The factory uses agricultural and forestry residues as raw materials, including sawdust, rice husks, corn cobs, bamboo sawdust, and dried woody plants. Once operating at more than 80% of its designed capacity, the plant requires over 15,000 metric tons of raw materials annually.

After being collected from grain-processing facilities, corn cobs are crushed into small pieces and mixed with additives before being compressed into charcoal briquettes. Alternatively, the crushed material is fed into a pressing machine to produce corn cob fuel sticks. These are similar to rice husk fuel logs.

The compression and briquetting process applies high pressure to increase the material’s density. A small amount of additives is incorporated to improve combustion efficiency. This allows the fuel to burn more completely without releasing harmful emissions. This technology not only creates a high-energy alternative to coal but also provides an effective solution for utilizing discarded corn cobs. In addition to delivering high heat output with minimal smoke, dust, and toxic emissions, corn cob fuel helps reduce environmental pollution. It does so by converting agricultural waste into a valuable energy source.

Biochar made from corn cobs has a calorific value of 7,000–8,500 calories per kilogram. This exceeds that of several types of anthracite fines, peat, lignite, and some coals mined in Suoi Bang, Muong Lum, and To Pan in Son La Province. One kilogram of this biochar can burn for up to 200 minutes without producing smoke or odor. Its carbon content ranges from 75% to 85%.

Although the compressed biomass fuel sticks have a calorific value that is 15–20% lower than coal (around 20 MJ/kg), they produce very little ash—no more than 5% of their total weight. As a result, they offer greater overall efficiency than coal, fuel oil, firewood, or liquefied petroleum gas (LPG) in many applications. In addition to being exported, these biomass fuel sticks and biochar products are widely used by agricultural and forestry processing facilities. They are also used by businesses operating thermal systems and industrial boilers, as well as other commercial and household energy users.

According to Giang Minh Thai, Deputy Director of Moc Chau Xanh Energy Co., Ltd., the company sources most of its corn cobs from Moc Chau and Yen Chau districts in Son La Province. Production operates year-round because corn harvesting seasons in the mountainous areas overlap across different locations. Each metric ton of corn cobs yields approximately 300 kilograms of charcoal. The company purchases corn cobs at VND 1,100 per kilogram, while the finished charcoal sells for VND 11,000 per kilogram. The entire process, from raw material procurement to the final product, takes about two weeks.

In addition to corn cobs, the company also uses by-products from the processing of bamboo, wood, and other agricultural materials. Among its products, bamboo charcoal and aromatherapy charcoal infused with essential oils for use in living rooms and bedrooms have become particularly popular in Japan.

In Vietnam, many restaurants that previously relied on honeycomb coal briquettes for cooking have switched to corn cob charcoal. It is a more cost-effective and cleaner alternative that significantly reduces smoke emissions.

Another notable feature is that emissions generated during production are captured and recirculated through a closed piping system. This prevents environmental pollution. Today, about 70% of the company’s output is exported, mainly to Japan and Arab countries.

By collecting and utilizing agricultural and forestry processing residues, Moc Chau Xanh Energy Co., Ltd. has helped increase farmers’ incomes. It has also created stable employment for around 25 local workers, with average monthly wages ranging from VND 4.5 million to VND 5 million.

Corn cobs are only one example of the abundant agricultural and forestry by-products available in Son La Province and the broader Northwest region of Vietnam. Expanding the efficient use of these renewable resources could significantly reduce dependence on coal in brick production and agricultural drying. Such an approach would not only provide a sustainable fuel source but also help reduce environmental pollution and mitigate climate change.