- Thesis topic: Application of Atmospheric Pressure Microwave Plasma on Pineapple Waste Treatment for Syngas Production

- Doi: https://doi.org/10.6840/cycu202400169

- Abstract: 

        Agricultural activities generate a large amount of waste every year. Random disposal or improper treatment of agricultural waste may pose a major risk to public health and lead to environmental pollution. The cost of processing agricultural waste may be relatively high, however, application of various agricultural waste treatment methods will lead to reduce environmental impact, promote sustainable development and make full use of the potential value of residues. Common methods include transformation to animal feed, anaerobic digestion to recover methane gas, composting to produce fertilizers and pyrolysis to produce biochar, etc. , and then implement the goal of circular economy.
Pineapples are an abundant agricultural products in Taiwan, generating more than 200,000 tons of waste every year. Unfortunately, post-harvest waste treatment is still insufficient and needs to be strengthened. If the lignin component of agricultural waste can be used to produce syngas, which will enhance the economic value of agricultural waste reuse. Syngas a mixture of carbon monoxide (CO) and hydrogen (H2), is important for several reasons across various industrial and energy applications. Syngas a versatile material that can be used to produce a wide range of valuable products, including electricity, heat, biofuels, chemicals, and synthetic natural gas. Syngas can be produced through biomass pyrolysis, the abundance of agricultural waste ensures a steady supply of raw material. The advantages of using Microwave plasma for waste treatment are rapid heating and high temperatures, energy efficiency, and enhanced product yield.
The results showed that the pyrolysis of pineapple waste was affected by plasma power of 800, 1000 and 1200 watts. The pineapple waste samples used in the study were crown and peel with dry and wet conditions. The peaks of the gas production system, the synthesis gas with 800 and 1000 watt power reached the peak at 6 and 7 minutes respectively, while the plasma with 1200 power reached the peak at 5 minutes. The wet pineapple waste sample with 1200 watt plasma power had the highest syngas molar ratio (H2/CO) output, the wet peel sample reached 4.18, the wet crown sample reached 4.00, dry sample had lower ratio with only 2.43 for pineapple peel and 2.42 for the pineapple crown. The molar ratio for syngas products are important because specific products require specific syngas molar ratios. The highest energy efficiency of biomass conversion is 72.6%, of dry crown sample with 1000 watts power followed by dry crown sample with 1200 watts power of 72.0% efficiency. The study used Taguchi methods to find the optimum parameters for the experiment. Material weight proved to be the most influential parameter, followed by plasma power, carrier gas flow and material type. For the pineapple waste biochar analysis, it was found that the detected functional groups include N-H stretching, O-H, C-N, C=O and C=C. The research results confirm application of microwave plasma on pineapple waste treatment can achieve the goal of resource recycling

Keywords: Pineapple Waste, Taguchi Method, Syngas Molar Ratio, Energy Efficiency