Data_ Integrating torrefaction of pulp industry sludge with anaerobic digestion to produce bioenergy and biochemicals: Techno-economic and environmental feasibility analysis

In order to improve the economic competitiveness of bioenergy carriers and biochemicals, they must be produced
from low-cost or no-cost feedstock and at a reduced operational expenses. In that regard, this study
focused on understanding the techno-economic feasibility of using pulp sludge as a low-cost alternative feedstock
to forestry biomass in torrefaction. Economic feasibility of further integrating pulp sludge torrefaction with
anaerobic digestion to produce energy, biomethane and volatile fatty acids (VFA) was also studied. The operational
expenses were around 8.2 and 2.04 M€ and the minimum selling price of torrefied pellets was 407 and
189 €/t for forestry biomass torrefaction and pulp sludge torrefaction respectively. In case of integrated approaches,
VFA production showed higher economic feasibility with a torrefied pellets selling price of 163 €/t
compared with biomethane production (213 €/t). The biomethane and VFA selling price can be reduced by 90
and 64% compared with current market price at torrefied pellets selling price of 260 €/t. Sensitivity analysis
revealed that, moisture content of the sludge is the main influencing parameter on the overall economic feasibility
of the pulp sludge torrefaction. The environmental analysis showed that pulp sludge torrefaction has higher
emissions compared with forestry biomass torrefaction.

为提升生物能源载体（bioenergy carriers）与生物化学品的经济竞争力，相关产品的生产必须采用低成本乃至零成本的原料（feedstock），并降低运营开支（operational expenses）。有鉴于此，本研究聚焦于探究以纸浆污泥（pulp sludge）作为林业生物质（forestry biomass）的低成本替代原料，用于生物质烘焙（torrefaction）的技术经济可行性（techno-economic feasibility）。此外，本研究还探讨了将纸浆污泥生物质烘焙与厌氧消化（anaerobic digestion）工艺进一步集成，以生产能源、生物甲烷（biomethane）及挥发性脂肪酸（VFA）的经济可行性。本次研究的运营开支分别约为8.2与2.04百万欧元，林业生物质烘焙与纸浆污泥烘焙所得烘焙颗粒的最低售价分别为407与189欧元/吨。对于集成工艺路线而言，与生物甲烷生产（最低烘焙颗粒售价213欧元/吨）相比，挥发性脂肪酸生产的最低烘焙颗粒售价为163欧元/吨，经济可行性更优。当烘焙颗粒售价为260欧元/吨时，生物甲烷与挥发性脂肪酸的售价可较当前市场价格分别降低90%与64%。敏感性分析结果表明，污泥含水率是影响纸浆污泥生物质烘焙整体经济可行性的核心参数。环境分析显示，纸浆污泥生物质烘焙的排放水平高于林业生物质烘焙。