Quang NamSeeing that plastic waste on the beach was polluting the environment, Truong Thanh Phuc and his group of friends used it to mix with rice husks and dolomite rock powder to create pellets as fuel.
On the first day of June, Truong Thanh Phuc, grade 11 Physics, Huynh Man Dat High School for the Gifted brought to Techfest Quang Nam 2024 the product “Renewable tablets – synergy from Kien Giang sea soil”, this is one of four products. Made by students and introduced by the Department of Science and Technology of Kien Giang province.
Truong Thanh Phuc introduces renewable pellet products at Quang Nam Startup Week. Image: Dak Thanh
Displaying pellets shaped like pressed wood chips makes many people curious to learn more. Phuc said he often witnessed more than 600 schools in Kien Giang having to burn their own garbage at school. The amount of dust and odors affected the health of students and surrounding people. Kien Giang is a province with a coastline of about 200 km long, an intricate network of rivers flowing into the sea, and houses are often built near river and sea banks. Many people still have the habit of throwing trash into rivers and seas, causing environmental pollution.
From those concerns, Phuc came up with the idea of finding a solution to handle this amount of plastic waste. Outside of class, male students research information online and learn that plastic waste not only in Vietnam but around the world is processed and recycled in small quantities, the rest is mainly burned or buried. fill. A new trend that is gaining attention in the world is the combination of controlled burning of plastic waste and energy recovery by using by-products and waste to produce environmentally friendly products.
During the three summer months of 2023, Phuc and four friends came up with ideas and selected suitable local by-products and waste products to act as catalysts and fire aids in the process of burning plastic waste. This helps improve the product’s combustion efficiency and reduce emissions of toxic substances into the environment.
After two months of research and testing, the students took plastic waste and rice husks, ground them and pressed them into fuel pellets. Test results show that plastic combined with rice husk will have more heat energy, helping to increase combustion efficiency. When burned, these two types will limit fly ash and toxic emissions into the environment because the large amount of silicon in rice husks can create an adsorption effect – absorbing toxic gases and heavy metals.
During experiments at the Vietnam Academy of Science and Technology, Phuc found that the most effective fuel pellet model in reducing harmful emissions was 70% rice husk and 30% plastic. However, Phuc and the team’s goal is to effectively treat plastic waste, so they cannot choose models with a lot of rice husks.
After that, Phuc decided to add some other catalytic fire aids when burning and looked for outstanding additives in Kien Giang. The project team chose dolomite stone powder because it reduces potassium and chlorine emissions in fly ash. In addition, dolomite can increase the combustion reaction, inhibit the evaporation of alkaline or alkaline earth metals and toxic gases during the combustion process, and reduce the slag effect.
The tablets were researched by Phuc and four students. Image: Dak Thanh
The principle here is to convert compounds with low melting temperatures into compounds with higher melting temperatures than the combustion temperature in the furnace. Thereby reducing the effect of creating slag deposits in the combustion chamber when forming a K2O-SiO2-CaO (MgO) oxide mixture with a high melting temperature. CaO (MgO) can also react with phosphates to form calcium phosphate (melting above 1600 degrees Celsius). CaO and MgO combine with SO2 to form mixed oxides CaO (MgO) SO4 (melting above 1200 degrees Celsius).
MgO does not combine with alkali even at high temperature so it is suitable for removing ash agglomeration and it can reduce K and Cl content in fly ash. CaO or MgO also promotes the conversion of very toxic gas hydrogen cyanide (HCN) into safer gases. Therefore, CaO and MgO in dolomite can reduce harmful emissions of SO2, NO and CO.
The test showed that the average HC and CO emissions of tablets containing dolomite were 0.1194 ml/g and 0.7167 ml/g, respectively. Meanwhile, plastic and rice husk emit emissions of 3.9753 ml/g and 1.7695 ml/g, respectively.
After three months, the group created pellets with the ratio of 62% plastic, 27% rice husk and 11% dolomite. When burned, the amount of HC, CO, NO and H2S emissions were reduced by 99.88% respectively; 96.39%; 46.29% and 44.44% compared to plastic and rice husk. “The tablets radiate heat quickly and reduce the phenomenon of slag formation, so they are very suitable for serving industrial production,” Phuc said, adding that the product is a technological solution for treating coastal plastic waste. in particular and plastic waste in general. Currently, there have not been any similar products or ideas announced before.
Chart of mixing ratio of resin, rice husk and Dolomite stone set of tablets. Image: Dak Thanh
The male student majoring in Physics said that the product was born in line with the era of renewable energy, reducing environmental pollution, using agricultural by-products, increasing income for rice farmers. Phuc cited evidence from research results that creating 1 ton of pellets costs about 4.7 million VND. When burned, the calorific value is about 7,500 kcal/kg, while using coal costs more than 10 million VND and the calorific value is about 5,000 VND. -6000 kcal/kg; Diesel oil priced at 18 million VND has a calorific value of about 10,000 kcal/kg.
“In addition to solving plastic waste, using the product helps customers reduce investment costs in waste treatment systems after incineration. They also reduce operating and maintenance costs of incinerators, and contribute to ensuring national energy security because it is no longer dependent on fuel imported from abroad at high prices,” Phuc said.
The product won third prize in the National Science and Technology Contest for high school students in the 2023-2024 school year and second prize in the National Competition for Students with Startup Ideas in 2023-2024 organized by the Ministry of Education. Organizational education and training. At the 2023 Kien Giang provincial youth creativity contest, the Phuc group’s renewable pellet won first prize.
The male student wants to spread and inspire everyone to replicate and develop a sustainable and innovative startup model.
Dr. Nguyen Xuan Niem, Deputy Director of the Department of Science and Technology of Kien Giang province, assessed that the product has potential in the future. “Through many years of monitoring scientific and technical competitions, I see that the project of pellets made from plastic waste combined with rice husk and dolomite stone powder can be applied in practice. This product uses raw materials in Kien Giang. Available and cheap. When used, they emit little toxic gas into the environment,” Mr. Niem said.