GOALI: Low-Ash Lignin Biofuel from Black-Liquor Streams

项目编号：1236759机构：克莱姆森大学标题：目标：从黑液溪流中提取低灰木质素生物燃料木质素是地球上最常见的有机化合物之一，约占所有有机碳的30%，在干燥基础上约占木材的30%。只有纤维素比它更丰富。如果木质素可以从纸浆和造纸厂的黑液副产品流中分离出来，在干燥、低灰分（0.5%灰分）的状态下，结果将是一种极好的生物燃料，其能量含量与煤基本相同。最近，克莱姆森和LLC2的研究人员发现，通过在中等温度和压力下将黑液与气态二氧化碳接触，木质素可以以低粘度、易于处理的液相形式从牛皮厂黑液中析出。此外，与起始黑液相比，这种液体-木质素相的灰分含量降低，随后可以通过有机可再生酸酸化进一步降低灰分含量。基于这一发现，该团队设想了一种液体木质素低灰净化（LLLAP）工艺，用于从纸浆和造纸厂的黑液流中回收清洁，低灰（0.5%）的生物燃料木质素。如果美国100多家大型纸浆和造纸厂中的50家实施这一变革，每年将产生300万吨生物质燃料作为煤炭替代电力生产，从而减少1500万吨二氧化碳/年。如果从长远来看，所有的纸浆和造纸厂都将所有的黑液送到LLLAP工艺中，美国电力生产的煤炭使用量将减少2%。这些都是重要的数字。该项目的目标如下：a。设计并构建一个连续工艺的研究规模的LLLAP工艺单元，并用于研究LLLAP操作参数对木质素产品质量的几个测量的影响，包括产量、灰分纯度和低聚物组成。确定LLLAP操作条件对产品质量的影响将是困难的，除非人们能更好地量化硫酸盐黑液的分子性质，特别是液体木质素。因此，通过对LLLAP过程的改进，即用压缩CO2连续增加pH降低至~9，可以分离出液体木质素的窄组分。然后对木质素的体积和分子性质进行表征。例如，对于绝对质量和低聚物信息，将采用MALDI质谱法。将液体木质素分馏，以酸化无盐形式进行分子表征，其中分子量和沉淀倾向等性质之间应该存在更良好的关系。先前对其他低聚体系的研究表明，高温凝胶渗透色谱的多级超临界萃取具有良好的选择性，有时甚至可以分离出单个物种。通过MALDI质谱法表征所得微组分的低聚物组成。将上述结果与pH值？建立液态木质素切屑的含盐量与低聚物组成之间的关系，以及它们对co2诱导沉淀的倾向，并利用这些结果对LLLAP进行改性，从而获得低灰分产品。全球已有20多家造纸和纸浆公司对LLLAP工艺和液体木质素技术表示了兴趣，因此，如果我们的低灰目标确实能够实现，将会有大量的许可机会。最后，从外联的角度来看，研究小组将通过SC ETV广播节目“Your Day”向公众传播研究结果。

PI: Thies, MarkProposal Number: 1236759Institution: Clemson UniversityTitle: GOALI: Low-Ash Lignin Biofuel from Black-Liquor StreamsLignin is one of the most common organic compounds on earth, comprising about 30% of all organic carbon and about 30% of wood on a dry basis. Only cellulose is more abundant. If lignin could be isolated from the black-liquor by-product stream of a pulp and paper mill in a dry, low-ash ( 0.5% ash) state, the result would be an excellent biofuel with essentially the same energy content as coal. Recently, Clemson and LLC2 researchers have discovered that lignin can be precipitated from kraft mill black liquor in the form of a low-viscosity, easy-to-handle liquid phase by contacting the black liquor with gaseous CO2 at moderate temperatures and pressures. Furthermore, this liquid-lignin phase, which has reduced ash content vs. the starting black liquor, can subsequently be further reduced in ash content by acidification with organic, renewable acids. Based on this discovery, the team envisions a liquid-lignin low-ash purification (LLLAP) process for recovering a clean, low-ash ( 0.5%), biofuel lignin from the black-liquor stream of a pulp and paper mill. If 50 of the 100+ large pulp and paper mills in the United States implemented this change, 3 million tons of biomass fuel would be generated a year as a coal replacement for electric power production, enabling a reduction of 15 million tons of CO2/yr. If in the longer term all pulp and paper mills sent all of their black liquor to the LLLAP process, there would be a 2% reduction in the use of coal for U.S. electric power production. These are significant numbers.The objectives of the project are as follows:a. Design and construct a continuous-process, research-scale unit of the LLLAP process and use to investigate the effect of LLLAP operating parameters on several measurements of lignin product quality, including yield, ash purity, and oligomeric composition.b. Determining the effect of LLLAP operating conditions on product quality will be difficult unless one can better quantify the molecular nature of kraft black liquor in general and of liquid lignin in particular. Thus narrow fractions of liquid lignin will be isolated via a modification of the LLLAP process, that is, by successive incremental pH reduction with compressed CO2 down to a pH of ~9. Then the bulk and molecular properties of this lignin will be characterized. For example, for absolute mass and oligomer information, MALDI mass spectrometry will be employed.c. Fractionate the liquid lignin for molecular characterization in the acidified, salt-free form, where a more well-behaved relationship between properties such as molecular weight and propensity for precipitation should exist. Previous work with other oligomeric systems has demonstrated that multi-stage, supercritical extraction followed sequentially by high-temperature gel permeation chromatography gives excellent selectivities, and individual species can even sometimes be isolated. Characterize resulting micro-fractions in terms of their oligomeric composition via MALDI mass spectrometry. Use the results with those from the above ?pH? fractionation step to establish a relationship between the salt content and oligomeric composition of liquid lignin cuts, and their propensity for CO2-induced precipitation, and use these results to modify LLLAP so as to achieve a lower-ash product.More than 20 paper and pulp companies around the world have expressed interest in the LLLAP process and liquid lignin technology, so there will be significant licensing opportunities if our low-ash targets can indeed be achieved. Finally, from an outreach standpoint, the research team will disseminate results to the general public through the SC ETV Radio program Your Day.