小径材高得率制浆清洁生产关键技术及产业化

本成果属林业工程领域。本项目充分利用了小径材、枝桠材等林业剩余物，对低质纤维原料均质浸渍、高效纤维解离、多点加药软化漂白、废水高效处理等关键技术进行了基础研究和应用开发，并取得了突破，自主开发出双螺旋挤压浸渍机和无架桥无短流高效漂白反应仓等关键装备，取得了多项创新性成果： 1．创制了低质纤维原料均质浸渍技术及逆向挤压浸渍设备。研究揭示了低质木片的药液浸透机理，突破了低质纤维原料均质浸渍软化、药液高效渗透等关键技术难点，提出了疏通微孔通道、控制金属离子等预处理技术，针对性开发出高效纤维解离技术及关键装备，实现了低发热效应下物料的破碎和解离，既高效利用了电能又保护了纤维的完整性。 2．开发了化学机械法节能组合磨浆技术。揭示了低质纤维原料的物理结构、化学性质，制浆过程中关键因素对制浆性能的影响和作用机理，及化学预处理对磨浆节能的影响规律，开发出纤维解离和高浓磨浆组合的磨浆技术。物料破碎和纤维解离通过双螺旋挤压机实现，利用高浓磨浆机发展强度，全流程优化配置电能输入强度，大幅度降低了磨浆能耗，电耗降低30%以上。 3．研发了多点加药和药液回用的节水漂白技术。利用组合漂白技术手段，突破了抑制化学品无效分解技术瓶颈，解决了企业使用低质原料生产高档纸浆过程中漂白和节水方面的关键问题。设计和建造了软化漂白一体仓，实现了纤维的充分软化，提高了漂白效率。经生产示范点应用和优化，节约化学品20%~30%。 4．设计建造了新型脉动式折流厌氧反应器。利用废水流体的大幅度湍动，动态改变水力对污泥的扰动和冲刷强度，解决了传统厌氧反应器易出现泥水混合不佳，易酸败，易钙化、不耐毒物冲击等难题，提高了污泥对废水浓度及毒物的耐受能力，使折流厌氧反应器对废水COD去除率提高18%~32%，沼气产生量提高15%~29%，高浓废水综合处理成本降低26%以上，生产废水处理后各项指标达到国家新排放标准。 本项目获授权发明专利7项、实用新型专利10项，发表学术论文108篇，其中SCI、EI和ISTP收录29篇。创新设计的国产化装备小径材高得率制浆清洁生产线，打破了我国化机浆生产技术及装备长期被国外垄断的局面，整体技术水平居国内领先、国际先进水平。

This achievement falls within the field of forestry engineering. This project has made full use of forestry residues including small-diameter logs and branch slash, carried out basic research and applied development on key technologies such as homogeneous impregnation of low-quality fiber raw materials, efficient fiber dissociation, multi-point dosing softening and bleaching, and efficient wastewater treatment, and achieved breakthroughs. It has independently developed core equipment such as double-screw extrusion impregnators and bridge-free, short-flow-free high-efficiency bleaching reaction chambers, and secured multiple innovative achievements:
1. Developed homogeneous impregnation technology for low-quality fiber raw materials and reverse extrusion impregnation equipment. The study revealed the liquid infiltration mechanism of low-quality wood chips, broke through key technical difficulties including homogeneous impregnation and softening of low-quality fiber raw materials and efficient penetration of chemical liquids, proposed pretreatment technologies such as unblocking microporous channels and controlling metal ions, and developed targeted efficient fiber dissociation technology and key equipment. It realized crushing and dissociation of materials under low heat generation effect, efficiently utilizing electric energy while protecting the integrity of fibers.
2. Developed energy-saving combined refining technology for chemi-mechanical pulping. It revealed the physical structure and chemical properties of low-quality fiber raw materials, the influence and mechanism of key factors on pulping performance during the pulping process, and the law of influence of chemical pretreatment on refining energy saving. It developed a combined refining technology integrating fiber dissociation and high-consistency refining. Material crushing and fiber dissociation are realized through a double-screw extruder, and the refining intensity is enhanced via a high-consistency refiner. The electric energy input intensity is optimally configured across the entire process, greatly reducing refining energy consumption, with power consumption reduced by more than 30%.
3. Developed water-saving bleaching technology with multi-point dosing and liquid recycling. Using combined bleaching technology, it broke through the technical bottleneck of inhibiting ineffective decomposition of chemicals, and solved the key problems in bleaching and water saving when enterprises use low-quality raw materials to produce high-grade pulp. It designed and built an integrated softening and bleaching chamber, realizing full softening of fibers and improving bleaching efficiency. After application and optimization in production demonstration sites, chemical consumption was reduced by 20% to 30%.
4. Designed and built a new-type pulsed baffled anaerobic reactor. By utilizing the large-scale turbulence of wastewater flow, it dynamically changes the hydraulic disturbance and scouring intensity on sludge, solving the common problems of traditional anaerobic reactors including poor mud-water mixing, easy souring, easy calcification, and inability to withstand toxic shocks. It improved the tolerance of sludge to wastewater concentration and toxic substances, increasing the COD removal rate of the baffled anaerobic reactor by 18% to 32%, biogas yield by 15% to 29%, reducing the comprehensive treatment cost of high-strength wastewater by more than 26%, and enabling all indicators of treated production wastewater to meet the new national discharge standards.
The project has been granted 7 invention patents and 10 utility model patents, and published 108 academic papers, among which 29 are indexed by SCI, EI and ISTP. The innovatively designed domestic small-diameter log high-yield pulping clean production line broke the long-term foreign monopoly on chemi-mechanical pulp production technologies and equipment in China, with its overall technical level ranking domestically leading and internationally advanced.