Densification and pyrolysis are two methods to upgrade biomass. To avoid ash fusion problems, NH₄H₂PO₄ and Ca(H₂PO₄)₂ were chosen as additives to mix with maize straw to produce biochar briquettes. Potassium transformation mechanisms between additives and biomass in pyrolysis were investigated by XRD, XRF, SEM-EDS, and simulation. Results show that additives accelerate the production of potassium phosphates, which have potential to improve ash fusion temperatures. Addition of additive enhanced deformation temperature (DT) and softening temperature (ST). Multiple linear regression equations between DT/ST and ash compositions were established. In combustion experiment, potassium fixation ratio was increased by additives. Potassium was in the form of high melting products, which finally inhibited fusion phenomenon.

中文翻译：

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磷基添加剂对热解过程中钾转化及生物炭团块灰分特性的影响

致密化和热解是提高生物质的两种方法。为避免灰烬熔化问题，可使用NH ₄ H ₂ PO ₄和Ca（H ₂ PO ₄）₂选择了与玉米秸秆混合以生产生物炭团块的添加剂。通过XRD，XRF，SEM-EDS和模拟研究了热解过程中添加剂与生物质之间钾的转化机理。结果表明，添加剂可加速磷酸钾的生产，磷酸钾具有改善灰分熔融温度的潜力。添加添加剂可提高变形温度（DT）和软化温度（ST）。建立了DT / ST和灰分组成之间的多个线性回归方程。在燃烧实验中，添加剂提高了钾的固定率。钾呈高熔点产物形式，最终抑制了熔融现象。