Abstract:

Pharmaceutical process residues (PPRs) are the byproducts from pharmaceutical industry that is popular and developed rapidly nowadays, involving two typical categories: Chinese herb residues (CHRs) and antibiotic fermentation residues (AFRs). Due to the dual attributes of renewable resource and hazardous waste of PPRs, to realize their safe and value-added utilization is of great significance to the society, the industry and the enterprise for environment protection and resource saving. In this study, focusing on the most accessible thermo-chemical conversion strategies, the research progress on the characteristics and influential factors, the evolution mechanisms of elements or components, and the properties of PPR-derived biofuels (solid, liquid and gas) are reviewed. Results demonstrate that the defective components (high moisture, rich nitrogen and abundant oxygen) are big obstacles to the conversion of PPRs into desirable biofuels, impeding their clean and efficient thermal utilization. On one hand, some pretreatments like dehydration and torrefaction can acquire enhanced performance of solid biofuels by the capabilities of upgrading and denitrogenating PPRs focusing on the evolution regulation of moisture, carbon and nitrogen fractions, while the enhancement effect is still limited together with the proper disposal of secondary byproducts. On the other hand, thermo-chemical conversion (pyrolysis, gasification or hydrothermal liquefaction) strategies on PPRs can produce favorable gaseous or liquid biofuels with higher energy density, nevertheless, the quality or the yield of resultant biofuels (pyrolytic gas, gasified gas, biogas and bio-oil) would be all inhibited in varying degrees due to the evolution and conversion of unfavorable/useless components (such as nitrogen, oxygen and ash) in PPRs. To fulfill stringent emission standards and high-efficient thermal utilization, more efforts should be made to develop satisfying strategies on the valorization of PPRs into biofuels in a more eco-friendly and profitable way. Furthermore, by comparing the properties and uses of various PPR-derived biofuels, hydrothermal integrated with subsequent thermo-chemical approaches seems to be a preferred option when focusing on the clean and efficient valorization of PPRs.

Key words: pharmaceutical process residues, thermo-chemical conversion, biofuel, defective properties, hydrothermal

摘要：

当前，我国制药产业蓬勃发展且增速迅猛，其工艺过程会不可避免地产生大量药渣，主要分为中药渣和抗生素菌渣两类，具有资源和废物双重属性。实现药渣的清洁高效资源化，在保护环境和节约资源层面，对于国家、行业和企业均具有积极意义，能源化利用是目前技术水平下最直接有效的途径。本文围绕热化学转化策略，以固、气、液燃料为目标产物，综述了目前两类药渣的热化学转化特点与影响因素、过程组分演化机制、产物特性规律等相关研究进展。现有研究结果表明，药渣的高水、富氮和丰氧等缺陷属性，是制约其清洁高效能源化的主要障碍。脱水、烘焙等预处理手段，通过基于水、碳、氮组分迁移演化调控的提质降氮机制，可强化药渣衍生固体燃料性能，但效果有限，同时会带来二次副产物的处置问题；热解、气化或水热液化等手段，可将药渣转化为具有更高能量密度的气液燃料，但反应中如氮、氧、灰等有害/无用组分在各相的演化和赋存机制，会不同程度地降低相应衍生燃料的品质或产率。因此，未来的研究应从探索更经济环保的热化学策略角度来解决上述缺陷属性，以实现药渣到衍生高值燃料的清洁高效转化。此外，通过现有结论的对比，提出了水热与后续热化学手段的耦合联用，可作为药渣全质清洁资源化的潜力方向。

关键词: 药渣, 热化学转化, 生物燃料, 缺陷属性, 水热