Currently, most of Taiwan's agricultural waste is disposed of by open burning, which causes air pollution and the increase of PM2.5 and carbon emissions that leads to strains in the relationship between environmental authorities and farmers. The future of agricultural waste prompts Professor Hung-ping Lin to pursue a circular economy and reduce energy waste from the perspective of recycling. The circular economy is different from the traditional industrial economic model of mining, manufacturing and discarding. Through redesigning products and business models, it can promote better resource utilization efficiency, eliminate waste and avoid polluting the natural environment.
Tainan’s Guantian is home to one of the largest water chestnut farm in Taiwan, with an annual output of nearly 3,700 tons. More than 90% of water chestnuts are abandoned for open burning or for incineration after collection by sanitation department. In order to solve this problem, Neng-tung Yen, executive of Guantian District, sought the feasibility of turning waste into energy for reuse and reached out to NCKU chemistry professor Hung-ping Lin. The research team scoured the market and the institutions involved for any technique. Although there are ways to make biochar, it requires the use of extra oil or electricity to produce it. Prof. Lin proposed an innovative way to turn water chestnut waste into biochar, which only requires heating during start-up. The team cooperated with the government to develop this technology, and the district office gathered non-governmental organizations to set up the "Tainan Guantian Black Gold Community Cooperative" to promote the merits of water chestnut shell charcoal. Under the official and non-governmental planning, the campaign was initiated by the government-academia-civil-industry cooperation for recycling and reusing agricultural waste.
The research team modified the conventional firing method, improved the furnace body, put the water chestnut shell into the furnace with temperature from 700 to 1000°C, controlled air flow, burned the remaining elements in the shell—which turns lignin into charcoal—and installed a detector for filtering at the furnace mouth to avoid secondary pollution. Fifteen to 17 kilograms of water chestnut shells can be transformed into 5 to 6 kilograms of water chestnut shell charcoal each time. After put into mass production, over 1,000 tons of the charcoal can be produced in one year. The charcoal burns itself in a high temperature and oxygen-free environment, resulting in very low carbon dioxide emissions, mitigating secondary pollution to the environment. The carbon fixation effect in the soil is excellent. The annual carbon reduction is equivalent to that absorbed annually by 1.1 Da'an Forest Parks. This innovative way resolves the problem of carbon emissions.
The team found that the charcoal can be sprayed in the field to preserve fertility, water and soil. Biochar itself is renewable energy and can be used as fuel to become green energy. In the process of producing water chestnut shell charcoal, a large amount of waste heat is generated, resulting in some energy emissions and losses. NCKU Prof. Wei-hsin Chen of aeronautics and astronautics and Prof. Hung-ping Lin jointly proposed the project of "Development of Materials and Systems for Conversion of Thermal Energy Cycle Resources" and received a subsidy for the second phase of the National Energy Program (NEP II) in 2018. The project aimed to recover the waste heat generated during chestnut coal burning, generate electricity from waste heat using thermoelectric chips, and complete the thermal energy cycle and power production. In addition, a wireless monitoring system was built to instantly understand the temperature change in the furnace and power generation data during the firing process to establish a complete example of an energy reuse system.
Prof. Hung-ping Lin’s research team has devoted many years to energy research. In addition to the above research, he has also worked on mesoporous nanomaterials and metal catalysts. Wastewater from industry contains significant amounts of heavy metals. The team converted this into nano-catalysts, turning pollution into resources, and applied it to catalyze the fuel-to-hydrogen system, providing new opportunities for energy research. This has not only turned pollution into a resource, but also converted fuel into energy, creating a win-win-win situation. At present, the team has also worked with Prof. Wei-Hsin Chen to actively propose a continuing industry-academia program to provide more energy-related research and innovation, hoping to make substantial contributions to energy issues.