Huang Guolin, Shi Jeffrey X, Langrish Tim A G
School of Chemical and Biomolecular Engineering, The University of Sydney, NSW 2006, Australia.
Bioresour Technol. 2007 Nov;98(15):2829-35. doi: 10.1016/j.biortech.2006.09.029. Epub 2006 Nov 7.
Aqueous ammonia mixed with caustic potash as wheat straw pulping liquor was investigated. The caustic potash did not only reduce the NH3 usage and cooking time, but also provided a potassium source as a fertilizer in the black liquor. Excess NH3 in the black liquor was recovered and reused by batch distillation with a 98% recovery rate of free NH3. The black liquor was further treated for reuse by coagulation under alkaline conditions. The effects of different flocculation conditions, such as the dosage of 10% aluminium polychloride, the dosage of 0.1% polyacrylamide, the reaction temperature and the pH of the black liquor on the flocculating process were studied. The supernatant was recycled as cooking liquor by adding extra NH4OH and KOH. The amount of delignification and the pulp yield for the process remained steady at 82-85% and 48-50%, respectively, when reusing the supernatant four times. The coagulated residues could be further processed as solid fertilizers. This study provided a new pulping process for wheat straw to reduce problems of discharge black liquor.
研究了将氨水与苛性钾混合作为麦草制浆蒸煮液的情况。苛性钾不仅减少了氨的用量和蒸煮时间，还在黑液中提供了钾源作为肥料。黑液中过量的氨通过间歇蒸馏回收并重复使用，游离氨的回收率为98%。黑液在碱性条件下通过混凝进一步处理以实现重复使用。研究了不同絮凝条件，如10%聚合氯化铝的用量、0.1%聚丙烯酰胺的用量、反应温度和黑液的pH值对絮凝过程的影响。通过添加额外的氢氧化铵和氢氧化钾，将上清液作为蒸煮液循环使用。当重复使用上清液四次时，该工艺的脱木素量和纸浆得率分别稳定在82 - 85%和48 - 50%。混凝残渣可进一步加工成固体肥料。本研究为麦草提供了一种新的制浆工艺，以减少黑液排放问题。
