水泥工业是重要的基础原材料行业,同时也是高耗能、高碳排放行业。我国生物质资源丰富,生物质替代燃料应用于水泥行业有助于降低化石能源消耗和碳排放,是实现我国水泥工业碳中和的主要途径之一。系统梳理并分析了生物质替代燃料在水泥行业的应用进展以及存在的相关问题,并给出了解决思路。较传统化石燃料,生物质燃料具有水分含量高、热值低、尺寸大等特点,应用于水泥生产时,可能造成燃料燃尽率降低、烟气量增大、热耗增加、熟料碱含量增加及波动增大等。国外建立了完善的固体回收燃料标准体系,为包括生物质在内的固体回收燃料规范化制备、规模化使用奠定了基础。全球水泥和混凝土协会发布数据显示,2020年全球水泥行业生物质燃料占比6.7%,其中,农业废物、有机废物、纺织废物占比最大,达32%;捷克、德国、波兰等国家生物质燃料占比超22%。与之相比,我国水泥行业使用生物质等替代燃料起步较晚,截至2021年使用替代燃料的水泥生产线占比不超过3%,热量替代率约为2%。从国内的应用情况来看,生物质替代燃料有助于降低单位熟料煤耗,仍存在与现有热工系统不适应、热量利用效率偏低、影响熟料产质量等问题。为降低生物质燃料直接投喂带来的负面影响,需对其进行预处理,对包括机械预处理和高温燃烧预处理在内的相关技术进行了介绍,对比分析各自的优缺点。最后分析生物质替代燃料应用于水泥行业存在的主要问题,并提出了针对性解决思路,包括强化中试研究,增强对实际生产的指导;完善相关标准,建立包括生物质在内的替代燃料产业链;利用水泥窑大量低温废气烘干生物质燃料,减少带入系统的水分;借助CFD模拟,优化生物质燃料喂入的相对位置;根据处置燃料种类,推广循环流化床等高温燃烧预处理技术;开发替代燃料智能控制系统,减少对于熟料产质量影响。水泥工业是我国碳减排的重要战场,生物质替代燃料必将在水泥行业展示出强大的生命力和广阔的应用前景,为我国双碳战略目标的实现做出重要贡献。

The cement industry is an important basic raw material industry, and also an industry with high energy consumption andhigh carbon emissions. China has abundant biomass resources. As alternative fuel, the application of biomass in the cement industry canhelp reduce the fossil energy consumption and carbon emissions, which is one of the main ways to achieve carbon neutrality for China′s cement industry. Progress and existing problems for biomass to be applied in the cement industry was analyzed, and solutions were gave.Compared with traditional fossil fuels, biomass fuel has such characteristics as high moisture content, low calorific value and large size.When it is used in cement production, these problems such as lower fuel burnout rate, higher flue gas volume, higher heat consumption,higher alkali content and larger fluctuation might be caused. A series of standards on solid recovered fuel (SRF) have been establishedabroad, laying a foundation for the standardized preparation and large-scale use of SRF including biomass in cement industry. Accordingto the dataissued by the Global Cement and Concrete Association, the proportion of biomass fuel in the global cement industry accountedfor 6.7% in 2020, among which agricultural, organic, diaper waste accounted for the largest proportion, i.e., 32%. The biomass fuel inCzech Republic, Germany, and Poland accounted for more than 22%. In contrast, the use of biomass and other alternative fuels in China′scement industry started late. By 2021, the proportion of cement production lines using alternative fuels was less than 3%, and the thermalsubstitution ratio was about 2%. From the perspective of domestic application, biomass as alternative fuel can help reduce fossil fuel consumption, but there are still some problems such as incompatibility with the existing thermal system, low efficiency of thermal utilization,and certain influence on the production and quality of clinker. In order to reduce the negative impact of biomass fuel, it is necessary topretreat it. Therefore, relevant technologies including mechanical pretreatment and high-temperature combustion pretreatment were introduced, and their advantages and disadvantages were compared. At the end of the paper, the main problems on the application of biomassfuels in cement industry were analyzed and the corresponding solutions were put forward. The solutions are to strengthen the pilot study andenhance its guidance to the actual production, improve relevant standards and establish an industry chain of alternative fuels including biomass, use the large amount of low-temperature waste gas from cement kiln to dry biomass fuel and reduce the water brought into the system, optimize the relative positions of biomass fuel fed to calciner by CFD simulation, popularize the high temperature combustion pretreatment technology such as circulating fluidized bed per to the type of biomass fuels, develop intelligent control system for alternative fuels and reduce the impact on clinker production quality. The cement industry is an important battleground for China′s carbon emission reduction. Biomass as alternative fuel will certainly show strong vitality and broad application prospects in the cement industry, and makeimportant contributions to the realization of China′s dual-carbon strategic objectives.

0 引言

1 生物质燃料的分类及特点

2 生物质燃料在水泥行业的应用现状

   2.1 国外水泥企业应用现状

   2.2 国内水泥企业应用现状

3 生物质燃料预处理技术

   3.1 机械预处理

   3.2 高温燃烧预处理

4 生物质燃料应用过程中面临的问题及解决思路

5 结语与展望