Green biorefinery (GBR) scenarios for a two-cut silage system: Investigating the impacts of sward botanical composition, N fertilisation rate and biomass availability on GBR profitability and price offered to farmers

In Ireland, grass is a readily available bioresource. It has previously been established that Green biorefinery (GBR) could become a potential use of Irish grasslands, and a blueprint for a sustainable GBR industry in Ireland has been developed. The objective of this paper is to use scenario analysis to investigate the sensitivity of the profitability of the GBR blueprint to variations in grass quantity and quality as a function of botanical composition, fertiliser application, and biomass availability. As an outcome of these scenario analyses, the price the GBR can offer to farmers above their production costs (€ t⁻¹ dry matter) was calculated. Results of the scenario analyses determined that GBR systems located in a catchment area of permanent pasture (Lolium perenne > 60%) with annual grass yields in the range of 9-12 t dry matter (DM) ha⁻¹, and supplied with grass biomass with a fibre content of 500-555 g kg⁻¹ DM and a protein content of 110-130 g kg⁻¹ DM, were viable. The most profitable scenarios were generated when nitrogen fertiliser application was greater than 90 kg ha⁻¹ a⁻¹. Biomass availability of less than 30% resulted in reduced profitability and for some scenarios resulted in a loss for both the GBR and farmer due to increased transport costs. Within the scenario assumptions of this study, grass feedstock was valued at €4-€56 t⁻¹ dry matter above production costs. However, this value depended on the yields and biomass availability of the GBR catchment area.     

Pyrolytic lignin removal for the valorization of biomass pyrolysis crude bio‐oil by catalytic transformation

BACKGROUND: The catalytic processes for valorizing the bio‐oil obtained from lignocellulosic biomass pyrolysis face the problem that a great amount of carbonaceous material is deposited on the catalyst due to the polymerization of phenol‐derived compounds in the crude bio‐oil. This carbonaceous material blocks the catalytic bed and contributes to rapid catalyst deactivation. This paper studies an on‐line two‐step process, in which the first one separates the polymerizable material and produces a reproducible material whose valorization is of commercial interest. RESULTS: The establishment of a step for pyrolytic lignin deposition at 400 °C avoids the blockage of the on‐line catalytic bed and attenuates the deactivation of a HZSM‐5 zeolite based catalyst used for hydrocarbon production. The origin of catalyst deactivation is coke deposition, which has two fractions (thermal and catalytic), whose content is attenuated by prior pyrolytic lignin separation and by co‐feeding methanol. The morphology and properties of the material deposited in the first step (pyrolytic lignin) are similar to lignins obtained as a by‐product in wood pulp manufacturing. CONCLUSIONS: The proposed reaction strategy, with two steps (thermal and catalytic) in series, valorizes the crude bio‐oil by solving the problems caused by the polymerization of phenolic compounds, which are obtained in the pyrolysis of the lignin contained in lignocellulosic biomass. Given that a by‐product (pyrolytic lignin) is obtained with similar properties to the lignin from wood pulping manufacturing, the perspectives for the viability of lignocellulosic biomass valorization are promising, which is essential for furthering its implementation in biorefinery processes. Copyright © 2009 Society of Chemical Industry     

A decision support tool for strategic planning of sustainable biorefineries

In this paper we formulate, implement, and test a model for technology and product portfolio design for a multi-product multi-platform biorefining enterprise. The model considered is an MILP financial planning model with the objective of maximizing the stakeholder value. Integer variables are used to select appropriate feedstocks, technologies, and products, material and capacity balances are used to design capacity and set production targets, while cash balances are used to describe investment and operations financing. Stakeholder value is described as the shareholder value with monetized environmental implications in terms of emissions mitigation costs and credits. Process integration schemes utilizing emissions are considered to reduce the emissions load and add to the bottom-line. A preliminary process design and product portfolio is provided as a result. Advantages of process integration are quantified using a central utilities facility and effluent recycles. Sensitivity analysis is conducted to determine important parameters that shape the objective function.     

Metrics for evaluating the forest biorefinery supply chain performance

For sustainable decision-making regarding biorefinery strategies, different criteria, i.e. economic, environmental, social, should be considered. However, the economic criteria typically do not consider market volatility, whereas today's market involves price and demand volatilities. Biorefinery strategies must be flexible to be robust to market volatility. Therefore, relevant metrics must be developed to quantify the system's performance against volatility. This paper presents metrics of flexibility and robustness which analyze the performance of the supply chain in a dynamic environment, providing additional information along with economic metrics. In this paper, the link between the two metrics, and how profitability and robustness change with flexibility are discussed. The results reveal that, although profitability does not always increase with more flexibility and there is an optimum level of flexibility, the system's robustness is improved by increasing flexibility. Moreover, a “conditional value-at-risk” parameter is introduced to show what patterns of sale lead to highest profit and robustnestness.     

Experimental evaluation of alkaline treatment as a method for enhancing the enzymatic digestibility of autohydrolysed Acacia dealbata

BACKGROUND: Acacia dealbata wood samples were subjected to hydrothermal processing in aqueous media, yielding a liquid phase (containing xylooligosaccharides) and a solid phase, enriched in cellulose, which was treated with alkaline solutions to obtain solids with improved susceptibility towards enzymatic hydrolysis. The effects of the most influential variables involved in the alkaline processing (sodium hydroxide concentration, temperature and reaction time) on solid yield, solid composition and kinetic parameters involved in the modelling of the enzymatic hydrolysis were assessed using the response surface methodology (RSM). RESULTS: Analysis of the RSM equations allowed selection of operational conditions (temperature = 130 °C, sodium hydroxide concentration = 4.5%, time of alkaline processing = 3 h), leading to selective removal of non‐cellulosic components and to a solid substrate highly susceptible to enzymatic hydrolysis. Operating at an enzyme loading of 20 FPU (filter paper units) g^?1 autohydrolysed, extracted solids (denoted AES) with a liquor to solid ratio of 30 g liquor g^?1 AES, solutions containing 29.7 g glucose L^?1 (corresponding to a yield of 47.3 g glucose per 100 g solids from autohydrolysis) were obtained after 48 h. CONCLUSION: Samples of Acacia dealbata wood were processed by autohydrolysis, sodium hydroxide treatment and enzymatic hydrolysis, yielding xylooligomers and processed solids highly susceptible to the enzymatic hydrolysis. Copyright © 2009 Society of Chemical Industry     

生物炼制与石油炼制一体化——促进我国生物质能源发展的有效对策之一

生物炼制是与石油炼制互补的新型工业生产模式,对我国生物质能源发展有重要作用。我国生物炼制产业发展目前处于起步阶段,面临着原料、技术等问题。针对我国国情,提出了在条件适当地区,生物炼制企业建设采取生物炼制与石油炼制一体化建设的设想。以燃料乙醇项目建设为例,通过对单独建设和一体化建设两种方案的比较,从成本、未来发展和原料供应等方面分析了一体化建设的优势。研究表明生物炼制与石油炼制一体化模式将对我国能源、化工等行业的可持续性发展起到促进作用。     

Coupling hydrothermal liquefaction and aqueous phase reforming for integrated production of biocrude and renewable H2

Lignin-rich stream from lignocellulosic ethanol production was converted into biocrude by continuous hydrothermal liquefaction (HTL) while hydrogen was produced by aqueous phase reforming (APR) of the HTL aqueous by-product. The effects of Na₂CO₃ and NaOH were investigated both in terms of processability of the feedstock as well as yield and composition of the obtained products. A maximum biocrude yield of 27 wt% was reached in the NaOH-catalyzed runs. A relevant amount of dissolved phenolics were detected in the co-produced aqueous phase (AP), and removed by liquid–liquid extraction using butyl acetate or diethyl ether, preserving the APR catalyst stability and reaching an hydrogen yield up to 146 mmol H₂ L⁻¹ AP. Preliminary mass balances integrating HTL and APR showed that the hydrogen provided by APR may account for up to 46% of the hydrogen amount theoretically required for upgrading the HTL biocrude, thus significantly improving the process performance and sustainability.     

硫酸盐法制浆企业的碳排放及碳捕获与利用技术

本文首先介绍了硫酸盐浆厂生产纸浆过程中CO₂的排放来源,进一步分析了“林浆一体化”企业的整体碳足迹,然后综述了温室气体排放核算方法,并介绍了硫酸盐浆厂的CO₂捕获及利用技术研究进展,包括黑液中酸析木质素的生产、沉淀碳酸钙的生产、塔罗油的提取、木质素纳米颗粒的生产等。最后探讨了将硫酸盐浆厂与生物质精炼厂相结合以进一步降低碳排放的可能性。     

生物精炼在造纸工业中的应用现状和前景

生物质是人类最丰富的可再生资源,科学合理地开发利用生物质是人类可持续发展的重要途径之一。生物精练可环境友好地将生物质资源转化为高附加值的、多元化的生物质产品和能源。本文概述了生物精炼发展的意义和现状,并重点论述了未来生物精炼制浆造纸厂的模式以及生物精炼在制浆造纸过程中的应用,同时提出了生物精炼在造纸工业应用中所面临的问题和解决建议。