Sustainable catalytic conversions of renewable substrates
Sustainable catalytic conversions of renewable substrates
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DOI：
10.1039/c4cy90025a
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发表时间：
2014-07
影响因子：
5
通讯作者：
P. Bruijnincx;Yuriy Román‐Leshkov
中科院分区：
文献类型：
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作者：
P. Bruijnincx;Yuriy Román‐Leshkov
将生物质及其衍生的平台分子转化为更可持续的化学品和燃料，是一个快速发展的研究领域。这些可再生原料的有效增值将需要在整个过程链中进行许多创新，从生物工程作物优化，改进预处理过程，将生物质饲料分离成其成分，最后将成分选择性地，能源和资源高效地转化为增值燃料和化学品。虽然这一努力涉及许多科学学科，但有一个领域被认为对最终实现这些基于生物质的转化途径特别有用：催化。事实上，催化被认为是未来发展具有竞争力的生物炼制的关键技术。这些生物精炼厂将需要以类似于目前的石化精炼厂的方式发展，其中化学品和燃料都是在一系列高度集成和高度优化的过程中生产的。今天，石化炼油厂生产的几乎所有燃料和85%以上的化学品在其生产过程中都至少经历了一个催化转化步骤。重要的是，这种转换具有极高的碳效率；也就是说，原料中不同馏分中的大部分碳原子都存在于最终产品中。因此，生物精炼厂也应该致力于不留下任何成分，产生很少或不产生废物，既生产生物基燃料，也生产化学品。对于生物燃料的生产，人们应该意识到，这些燃料将只构成未来可再生能源组合的一部分，甚至可能是一个过渡或利基解决方案，因为长期的技术发展几乎肯定是基于直接转换和储存来自太阳能和风能等能源。生物燃料对我们面临的可持续性挑战做出的重要但部分的贡献，当然应该在考虑生物质的可用性和来源时考虑在内。在化学生产方面，生物质有可能成为未来化学工业的主要原料。来自生物质的高附加值产品可以为向可持续燃料和商品化学品的理想和必要过渡提供重要推动力。因此，可以遵循两种转化途径：要么将生物质转化为现有的化学品（例如，“插入”或化学相同的绿色替代品），要么为化学工业产生新的构建模块/最终产品。插入式生物基化学品具有解决现有市场和利用现有基础设施的优势，但必须以具有成本竞争力的方式生产。从经济可行性的角度来看，生物基化工生产将受益于近期页岩气产量的激增。一方面，氢的可用性将继续增加，从而减少对还原过程的限制；另一方面，传统炼油厂的产品分布将继续发生变化，从而为生物基工艺带来新的机会。例如，用裂解装置中较轻的页岩气原料取代石脑油用于乙烯生产，导致裂解装置产量的化学成分发生了巨大变化，从而影响了丁二烯和BTX等关键大宗化学品的供应。这些情况显然为开发具有竞争力的生物基化学品生产路线开辟了机会。除了产品固有的可持续性外，生物基路线为新产品提供了改进或前所未有的材料性能的可能性。近年来报道了许多新产品，但通常来源于相对较少的构建块（例如聚乳酸）。新开发的平台分子，如5-羟甲基糠醛或γ-戊内酯，被认为具有最终取代烯烃和芳烃的潜力，而烯烃和芳烃是当今化学工业的基石。然而，新产品的市场渗透并不是一件容易的事
The conversion of biomass and the platform molecules derived from it into more sustainable chemicals and fuels, is a rapidly evolving field of research. Efficient valorization of such renewable feedstocks will require many innovations in the entire process chain ranging from crop optimization by bioengineering, improved pretreatment processes to separate the biomass feed into its components and finally the selective, energyand resource-efficient conversion of the constituents into value-added fuels and chemicals. While many disciplines of science are involved in this effort, one field is considered to be particularly instrumental to the eventual realization of these biomass-based conversion routes: catalysis. Indeed, catalysis is considered as a key, enabling technology for the development of future, competitive biorefineries. These biorefineries will need to be developed in an analogous manner to the current petrochemical refineries, wherein both chemicals and fuels are produced in a collection of highly integrated and highly optimized processes. Today, virtually all fuels and over 85% of the chemicals that come out of petrochemical refineries have seen at least one catalytic conversion step in their production process. Importantly, such conversions are performed with extremely high carbon efficiencies; that is, most of the carbon atoms in the various fractions of the feed are found in the end products. Biorefineries should therefore also aim to leave no component behind, to produce little to no waste, and to produce both biobased fuels as well as chemicals. For biofuel production, one should realize that these fuels will constitute only part of the future renewable energy mix, and might even be a transitional or niche solution as longer-term technological developments will almost certainly be based on the direct conversion and storage of energy from sources such as the sun and wind. The important, but partial contribution that biofuels will make to the sustainability challenge that we face should certainly be factored in when biomass availability and sourcing is considered. For chemical production, biomass has the potential to become a dominant feedstock in the future chemical industry. High value-added products derived from biomass can provide an important driver for the desired and necessary transition to sustainable fuels and commodity chemicals. As such, two conversion paths can be followed: either convert biomass into existing chemicals (e.g., ‘drop-in’ or chemically identical green replacements), or generate new building blocks/end products for the chemical industry. Drop-in biobased chemicals offer the advantage of addressing an existing market and using an existing infrastructure, but have to be produced in a costcompetitive manner. From the point of view of economic viability, biobased chemical production will benefit from the recent surge in shale gas production. On the one hand, hydrogen availability will continue to increase, thus decreasing restrictions on reductive processes; and on the other, the product distribution from traditional refeineries will continue to change, thus generating new opportunities for biobased processes. For instance, the replacement of naphtha with lighter feeds from shale gas in crackers for ethylene production has resulted in a drastic change in the chemical composition of the cracker output and, consequently, has affected the supply of key bulk chemicals such as butadiene and BTX. These scenarios clearly open up opportunities for the development of competitive biobased routes for the production of chemicals. Biobased routes to new products offer the possibility of improved or unprecedented material properties in addition to the inherent sustainability of the product. Many new products have been reported over recent years, but have been often derived from relatively few building blocks (e.g., polylactic acid). Newly developed platform molecules, such as 5-hydroxymethylfurfural or γ-valerolactone, are thought to have the potential to ultimately replace the olefins and aromatics that are the building blocks of the chemical industry of today. However, market penetration for new products is not an easy task, and