The Influence of Biomass Cokes on the Microstructure and Thermal Shock Resistance of MgO-C Refractories

In this study,biomass cokes from sunflower seed hull(SFSH)and wood pellets(WP)were added to a MgO-C batch(3 mass%C)to replace 1.1 mass%of graphite.After hardening and carbonizing the samples,the influence of the biomass cokes on the microstructure and thermal shock resistance was investigated.The replacement of flaky graphite by carbonized WP and SFSH reduced the bulk density and increased the apparent porosity after pressing and carbonization,but the degree was only marginal.This was confirmed by SEM investigations,where the biomass-coke containing samples exhibited a microstructure with a higher amount of pores between the fine MgO grains.The thermal shock resistance of the porous wood pellet coke containing MgO-C is at the same level as the reference sample but not superior to it.

垃圾气化分析及其对中国实现碳中和与无废城市建设的贡献

气化是实现化学利用碳资源(尤其是煤)生产化学品和燃料的关键工艺。目前,全球拥有超过272套气化装置,主要应用于煤化工,尤其在中国。由于在一个化工厂通过技术集成达到工业规模的集中生产可实现减少二氧化碳排放并促进碳密集型行业的循环经济,如废物管理、化学和交通行业,因此,近年来全球对垃圾气化的兴趣日益浓厚,尤其是那些在煤气化技术方面积累了丰富的人力资本和运营经验以及拥有完整Coal-to-X产品价值链的国家,如中国,在挖掘通过垃圾气化实现Waste-to-X的潜力方面处于独特的地位。具体而言,废弃物可用于补充煤气化生产如下产品:(1)具有较低或零碳足迹的化学品,具体取决于废物是来源于化石资源还是生物资源。(2)来自生物废弃物的零碳足迹的绿色“氢”,以补充或替代来自煤气化或蒸汽重整得到的“灰色”氢,以供给氢能汽车,并推动工业脱碳。(3)来自生物废弃物的CO_(2)中性合成液体燃料,用于交通工具,以补充或替代石油燃料和合成煤制液体燃料。然而,迄今为止,利用垃圾作为气化原料的操作经验有限,并且文献中也很少涉及以前和当前的工业垃圾气化经验。为了填补这些空白,本研究介绍了1980年代至2000年代德国的两项开创性技术发展—贝伦拉特(Berrenrath)和SVZ黑水泵(即Sekundärrohstoff-Verwertungszentrum:黑水泵二次原料回收中心),并分享了以下三种垃圾与煤共气化技术(即Waste&Coal-to-X)的相关认识和经验教训:固定床气化:鲁奇干法排渣技术以及BGL熔渣气化技术。流化床气化:高温温克勒(HTW-High Temperature Winkler)气化工艺。气流床气化:GSP(Gaskombinat Schwarze Pumpe),即西门子气化工艺。此外,本研究也总结了目前全球100%垃圾气化技术的发展,即Waste-to-X。在气化技术的三种类型中,研发领域和工业界均对流化床与气流床(作为后期气化)技术的结合产生了浓厚的兴趣,这里介绍三个相关技术的重大发展—Ebara-Ube、Enerkem和ThermoChem Recovery International的技术。除此之外,固定床气化工艺的发展也得到了关注,本文介绍了两个相关技术的重大发展—InEnTec(将固定床与等离子气化相结合)和Sierra Energy(改造传统高炉转炉进行垃圾气化)的技术。借鉴以往和当前的国际发展经验,凭借其庞大的气化规模和丰富的专业知识,逐步将垃圾作为原料融入到煤气化中可以作为中国迈向循环经济和无废城市的第一步。将垃圾与煤共气化技术作为通向垃圾气化的桥梁,不仅可以使中国利用现有的人力资本和基础设施,还可以创造新的就业和商业机会,并支持中国实现可持续的垃圾管理策略,即在进行焚烧和填埋之前先进行减量、再利用和再循环。然而,将煤气化技术直接用于垃圾气化具有挑战性并且充满了较大的风险。本研究分享了贝伦拉特和SVZ黑水泵在垃圾与煤共气化方面遇到的各种运行问题以及从中得到的最新认识。然后介绍了这些积累的经验及认识是如何被考虑并应用到德国弗莱贝格工业大学的能源化工所开发的Flexi技术当中,包括:基于BGL熔渣气化技术开发FlexiSlag固定床气化技术。基于GSP气化技术开发FlexiEntrained气流床气化技术。基于HTW气化技术开发FlexiCOORVED气化技术。目前,Flexi技术在德国弗莱贝格开展中试规模运行,其目标是实现:(1)多元原料气化(例如生物质、煤、石油焦、不同类型的废物);(2)100%垃圾气化;(3)灵活的目标产品(即调整配置得到最大化的合成气产出,其中可含有最大化或最小化的甲烷、焦油和油的含量)以支持全球向碳中和和无废城市转型。鉴于全球(包括中国)实现无废城市和碳中和的目标,垃圾气化技术的长远发展不仅要向100%垃圾气化发展,还必须满足以下可持续性标准才能做出实质性的贡献:(1)多元进料,能够灵活利用多种类型的(废物)原料。(2)碳回收率最大化,以确保垃圾中的碳转移到产品中,而不是在整个过程链中以CO_(2)的形式排放到环境中。(3)通过生产玻璃渣、从渣中回收金属和零废水排放,将环境影响降至最低。本研究最后根据上述三个可持续性标准对三种气化类型进行了定性的整体评价,阐述了它们在垃圾气化应用中的优势和劣势。

Selective conversion of syngas to propane over ZnCrO_x-SSZ-39 OX-ZEO catalysts

Oxide-Zeolite(OX-ZEO) bifunctional catalyst design concept has been exemplified in several processes to direct conversion syngas to value-added chemicals and fuels such as mixed light olefins, ethylene, aromatics and gasoline.Herein we demonstrate that the product can be steered toward liquefied petroleum gas(LPG) with a selectivity up to 89% in hydrocarbons especially propane selectivity reaching 80% at CO conversion of 63% using ZnCrOx-H-SSZ-39 catalyst.Interestingly, the quantity of the acid sites of SSZ-39 does not influence obviously the hydrocarbon distribution but the strength is crucial for selective formation of propane.This finding provides an alternative route of LPG synthesis from a variety of carbon resources via syngas.

A concept to support the transformation from a linear to circular carbon economy:net zero emissions,resource efficiency and conservation through a coupling of the energy,chemical and waste management sectors

Coal and carbon-containing waste are valuable primary and secondary carbon carriers.In the current dominant linear economy,such carbon resources are generally combusted to produce electricity and heat and as a way to resolve a nation’s waste issue.Not only is this a wastage of precious carbon resources,which can be chemically utilized as raw materials for production of other value-added goods,it is also contrary to international efforts to reduce carbon emissions and increase resource efficiency and conservation.This article presents a concept to support the transformation from a linear‘one-way cradle to grave manufacturing model’toward a circular carbon economy.The development of new and sustainable value chains through the utilization of coal and waste as alternative raw materials for the chemical industry via a coupling of the energy,chemical and waste management sectors offers a viable and future-oriented perspective for closing the carbon cycle.Further benefits also include a lowering of the carbon footprint and increasing resource efficiency and conservation of primary carbon resources.In addition,technological innovations and developments that are necessary to support a successful sector coupling will be identified.To illustrate our concept,a case analysis of domestic coal and waste as alternative feedstock to imported crude oil for chemical production in Germany will be presented.Last but not least,challenges posed by path dependency along technological,institutional and human dimensions in the sociotechnical system for a successful transition toward a circular carbon economy will be discussed.

An integrated approach to the key parameters in methanol‐to‐olefins reaction catalyzed by MFI/MEL zeolite materials

Identification of the catalyst characteristics correlating with the key performance parameters including selectivity and stability is key to the rational catalyst design. Herein we focused on the identification of property-performance relationships in the methanol-to-olefin(MTO) process by studying in detail the catalytic behaviour of MFI, MEL and their respective intergrowth zeolites. The detailed material characterization reveals that both the high production of propylene and butylenes and the large Me OH conversion capacity correlate with the enrichment of lattice Al sites in the channels of the pentasil structure as identified by 27 Al MAS NMR and 3-methylpentane cracking results. The lack of correlation between MTO performance and other catalyst characteristics, such as crystal size, presence of external Brønsted acid sites and Al pairing suggests their less pronounced role in defining the propylene selectivity. Our analysis reveals that catalyst deactivation is rather complex and is strongly affected by the enrichment of lattice Al in the intersections, the overall Al-content, and crystal size. The intergrowth of MFI and MEL phases accelerates the catalyst deactivation rate.

Sustainable waste management for zero waste cities in China:potential,challenges and opportunities

Waste is a valuable secondary carbon resource.In the linear economy,it is predominantly landfilled or incinerated.These disposal routes not only lead to diverse climate,environmental and societal problems;they also represent a loss of carbon resources.In a circular carbon economy,waste is used as a secondary carbon feedstock to replace fossil resources for production.This contributes to environmental protection and resource conservation.It furthermore increases a nation’s independence from imported fossil energy sources.China is at the start of its transition from a linear to circular carbon economy.It can thus draw on waste management experiences of other economies and assess the opportunities for transference to support its development of‘zero waste cities’.This paper has three main focuses.First is an assessment of drivers for China’s zero waste cities initiative and the approaches that have been implemented to combat its growing waste crisis.Second is a sharing of Germany’s experience-a forerunner in the implementation of the waste hierarchy(reduce-reuse-recycle-recover-landfill)with extensive experience in circular carbon technologies-in sustainable waste management.Last is an identification of transference opportunities for China’s zero waste cities.Specific transference opportunities identified range from measures to promote waste prevention,waste separation and waste reduction,generating additional value via mechanical recycling,implementing chemical recycling as a recycling option before energy recovery to extending energy recovery opportunities.

Chemical storage of hydrogen in synthetic liquid fuels:building block for CO_(2)-neutral mobility

Green hydrogen is anticipated to play a major role in the decarbonization of the mobility sector.Its chemical storage in CO_(2)-neutral synthetic liquid fuels is advantageous in terms of safety and reliability compared to other hydrogen storage developments,and thus represents a complementary building block to developments in electric and hydrogen mobility for the low-carbon transition in the mobility sector.Its development is especially relevant for transport sectors which will have no alternatives to liquid fuels in the foreseeable future.In this paper,three alternative technological routes for the chemical storage of hydrogen in CO_(2)-neutral synthetic liquid fuels are identified and comparatively evaluated in terms of feedstock potential,product potential,demand for renewable electricity and associated costs,efficiency as well as expected market relevance.While all three routes exhibited similar levels of overall efficiencies,electricity-based liquid fuels in Germany are currently limited by the high cost and limited supply of renewable electricity.In contrast,liquid fuels generated from biogenic waste have a constant supply of biogenic feedstock and are largely independent from the supply and cost of renewable electricity.

Solvent-Free Synthesis of ITQ-12, ITQ-13, and ITQ-17 Zeolites

Development of the sustainable routes for synthesis of ITQ-family zeolites is very important because of their unique structures and excellent catalytic and adsorptive properties.The burden of costly raw materials and low efficiency of synthesis put a strong challenge for their widespread commercial application.Here,we show an alternative and simple route for synthesis of ITQ-12,ITQ-13,and ITQ-17 zeolites using commercially available organic templates by a facile grinding process of anhydrous starting raw solids,followed by heating at 140-180 ℃.Compared with the conventional hydrothermal synthesis,this approach has obvious advantages such as employment of low-cost organic templates with very high effectiveness,high yield of zeolite products,short crystallization time,and relatively simple procedures.This methodology might open a pathway to synthesize ITQ zeolites with more sustainable manner.

A“Sequential Design of Simulations”approach for exploiting and calibrating discrete element simulations of cohesive powders

The flow behaviours of cohesive particles in the ring shear test were simulated and examined using discrete element method guided by a design of experiments methodology.A full factorial design was used as a screening design to reveal the effects of material properties of partcles.An augmented design extending the screening design to a response surface design was constructed to establish the relations between macroscopic shear stresses and particle properties.It is found that the powder flow in the shear cell can be classified into four regimes.Shear stress is found to be sensitive to particle friction coefficient,surface energy and Young’s modulus.A considerable fluctuation of shear stress is observed in high friction and low cohesion regime.In high cohesion regime,Young’s modulus appears to have a more significant effect on the shear stress at the point of incipient flow than the shear stress during the pre-shear process.The predictions from response surface designs were validated and compared with shear stresses measured from the Schulze ring shear test.It is found that simulations and experiments showed excellent agreement under a variety of consolidation conditions,which verifies the advantages and feasibility of using the proposed“Sequential Design of Simulations”approach.

On the determination of particle impact breakage in selection function

This paper presents a thorough study of particle impact breakage in selection function with a unified breakage criterion.The impact mode and breakage pattern for particulate materials are classified based on a significant review of well-established impact testers.It was found that the lack of a unified breakage criterion to determine the breakage probability disables a direct comparison of particle breakage propensity from different impact loading testers.The literature breakage models to describe the breakage probability are reviewed where the advantage and drawback of these models are scrutinized.The sourced literature breakage models are compared with the zeolite breakage datasets in a unified breakage criterion to evaluate the model performance.A novel computational modelling workflow for a milling process is proposed to provide a guidance in implementing the digital twin in milling process prediction.The breakage probability models,i.e.the selection functions are comprehensively assessed in population balance model to examine the model serviceability.The model simplicity and fidelity in the model assessment are specifically discussed and the value of digital twin in substantially reducing the experimental trials is highlighted.

Discrete element modelling of the quasi-static uniaxial compression of individual infant formula agglomerates

Infant formula is usually produced in an agglomerated powder form. These agglomerates are subjected to many transient forces following their manufacture. These can be difficult to quantify experimentally because of their small magnitudes and short durations, Numerical models have the potential to address this gap in the experimental data. The objective of the research described here was to calibrate a discrete element model for these agglomerates using experimental data obtained for quasi-static loading, and to use this model to study the mechanics of the particle response in detail. The Taguchi method was previously proposed as a viable calibration approach for discrete element models. In this work, the method was assessed for calibration of the model parameters （e.g., bond stiffnesses and strengths） considering three responses： the force at failure, strain at failure and agglomerate stiffness. The Weibull moduli for the simulation results and the experimental data were almost identical following calibration and the 37% characteristic stresses were similar. An analysis of the energy terms in the model provided useful insight into the model response. The bond energy and the normal force exerted on the platens were strongly correlated, and bond breakage events coincided with the highest energy dissipation rates.