新工艺将湿咖啡渣快速转化为生物炭New technology rapidly converts wet coffee grounds into biochar

韩国地球科学与矿产资源研究所科学家开发出一项新工艺，能在90秒内将湿咖啡渣直接转化为高质量生物炭，完全省去干燥和脱油环节。这一成果为高水分有机废物转化为有价值的燃料与碳材料，开辟了一条快速节能的新途径。相关论文发表于最新一期《化学工程杂志》。

全球每年会产生超过1000万吨咖啡渣，其中绝大多数最终被填埋或焚烧。咖啡渣含水量极高，将其转化为燃料或碳产品通常需要耗能巨大的预干燥过程，让大规模资源回收在经济上难以实现。

为破解这一难题，团队开发了火焰等离子体热解（FPP）技术，通过燃烧液化石油气和压缩空气，产生温度约800℃—900℃的等离子火焰，可在常压等离子体条件下直接处理含水量约55%的生物质。

FPP技术完全免去了预干燥处理。加热时会迅速蒸发生物质颗粒内部的水分，由此产生的压力积聚引发微尺度爆炸——即“爆米花效应”。这一效应既能增强碳化，又能塑造出高度多孔的结构。水分因此不再是障碍，反而成为蒸汽活化剂，加速反应并提升产品品质。

在优化条件下，团队仅用90秒便将湿咖啡渣完全转化为固体生物炭。其热值高达29兆焦耳/千克，比原始咖啡渣（21.8兆焦耳/千克）高出约33%，与无烟煤不相上下。此外，在这一过程中，硫化合物被彻底清除，杜绝了燃烧时硫氧化物排放；比表面积从1.5平方米/克飙升至115.4平方米/克，意味着它在活性炭前驱体或吸附材料领域极具潜力。这些特性使最终得到的生物炭既可作为可再生固体燃料，也能充当高价值碳材料，应用于环境与工业领域。

Scientists from the Korea Institute of Earth Science and Mineral Resources have developed a new process that can directly convert wet coffee grounds into high-quality biochar within 90 seconds, completely eliminating the need for drying and degreasing processes. This achievement has opened up a fast and energy-saving new path for the conversion of high moisture organic waste into valuable fuels and carbon materials. The relevant paper was published in the latest issue of the Journal of Chemical Engineering.

More than 10 million tons of coffee grounds are produced globally each year, with the vast majority ultimately being landfilled or incinerated. Coffee grounds have extremely high water content, and converting them into fuel or carbon products typically requires a highly energy intensive pre drying process, making large-scale resource recovery economically difficult to achieve.

To solve this problem, the team developed flame plasma pyrolysis (FPP) technology, which generates a plasma flame at a temperature of about 800 ℃ -900 ℃ by burning liquefied petroleum gas and compressed air. It can directly process biomass with a moisture content of about 55% under atmospheric pressure plasma conditions.

FPP technology completely eliminates pre drying treatment. When heated, the moisture inside the biomass particles evaporates rapidly, causing pressure accumulation and triggering a microscale explosion known as the "popcorn effect". This effect can enhance carbonization and shape highly porous structures. Moisture is no longer a barrier, but instead becomes a steam activator, accelerating reactions and improving product quality.

Under optimized conditions, the team completely converted wet coffee grounds into solid biochar in just 90 seconds. Its calorific value is as high as 29 megajoules per kilogram, which is about 33% higher than the original coffee grounds (21.8 megajoules per kilogram) and comparable to anthracite. In addition, during this process, sulfur compounds are thoroughly removed, eliminating the emission of sulfur oxides during combustion; The specific surface area has skyrocketed from 1.5 square meters per gram to 115.4 square meters per gram, indicating its great potential in the field of activated carbon precursors or adsorbent materials. These characteristics enable the final biochar to be used as both a renewable solid fuel and a high-value carbon material, applied in the fields of environment and industry.