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In the field of alternative diesel fuels, so-called oxymethylene ethers (OMEs) are currently intensely investigated. Particularly OMEs of the type CH3O(CH2O)nCH3 with n = 3–5 exhibit promising fuel properties and combustion characteristics with strongly reduced particle and NOx emissions. According to their molecular structure, OMEs can be produced from methanol thus enabling sustainable production strategies from CO2 and renewable resources. Compared to the methyl derivatives, analogous compounds with higher alkyl groups (oxymethylene dialkyl ethers, OMDAEs) have been investigated to a much lesser extent. Thus, commercially available OMDAEs, i.e. compounds of the type ROCH2OR bearing ethyl, propyl, butyl and 2-ethylhexyl groups, have been studied. Furthermore, asymmetric compounds of the type R1OCH2OR2 have been synthesized from the symmetric compounds employing transacetalization reactions catalyzed by zeolite BEA-25. The OMDAEs have been characterized by spectroscopic and spectrometric methods and several physico-chemical, thermodynamic and fuel-related data have been determined and compared. Despite their structural peculiarities, such as the oxygen-containing acetal moiety in the molecular backbone, all OMDAEs exhibit properties similar to conventional diesel fuels. Based on experimental and analytical data, the development of tools for the prediction of properties by a simple regression method is described. Furthermore, the suitability of group contribution modelling is investigated for OMDAE compounds.

The environmental impact of the increasing anthropogenic CO2 emissions and the depletion of essential resources, once subjects of concern only for a minority of specialists, are now in the focus of many institutions and are de facto top priorities in many agendas. The ensuing environmental regulations, improved safety requirements, and growing critical public view on the chemical industry are the main reasons for an intense search for alternative synthetic routes to commodity chemicals and specialty chemicals. The skillful utilization of waste biomass, an inexhaustible resource, is revealed to be an important tool for a balanced CO2 management and the way to promising feedstock for many chemical and biochemical syntheses. The scope of the present contribution is to outline the main differences between chemical and biotechnological synthesis routes starting from waste biomass, focusing on C4-chemicals as an exemplary case study.

Lignin represents the most significant potential source of sustainable aromatic compounds. Currently, the vast majority of technical lignin could be sourced from industrial paper production and in particular the Kraft process, where it is conventionally combusted for chemicals recovery and heat generation (e.g. for plant operation). While in recent years several efforts have concerned the conversion of native lignin (i.e. as found in nature) during biomass processing, there has also been significant focus on the “Base Catalyzed” conversion of technical lignin. This process is of significant interest, since it could be potentially integrated into existing Kraft mill infrastructure. The following review paper focuses on the development of the hydrothermal base catalyzed depolymerization (HBCD) of lignin, as a basis to produce valuable chemical compounds. Focus will be placed on NaOH catalyzed reactions in the aqueous phase, as this approach is considered the most promising. Focus is placed on reaction conditions and characterization of monomeric aromatic compounds from the HBCD approach. Oligomers, as largest product fraction, is also considered, however, these are seldom analyzed in detail in the literature and ideas on further use are scarce. The review also addresses findings in literature concerning the assessment of the solid, liquid, and gas product streams arising from HBCD. From this paper, process conditions for HBCD reactions can be derived and it is shown that the solid phase has a high potential for further valorization and downstream processing.

Industrial Kraft Lignin (KL) prepared by LignoBoost® technology was treated via hydrothermal base catalysed depolymerisation (HBCD). KL was dried and divided into methanol soluble and insoluble fractions. The insoluble fraction was treated in 1 M NaOH (aq) at 300 °C. After precipitation with HCl (aq), the solids yield was ca. 60 wt%. These solids demonstrated improved thermal stability and carbon content, increased solubility in MeOH and reduction in polydispersity. With a view to the use of the product in the preparation of carbon-based materials (e.g. carbon fibres (CF)), thermal analysis was undertaken, revealing a lack of a glass transition below the decomposition temperature, excluding melt pinning. However, a high solubility in organic solvents renders the product a suitable candidate for solvent spinning and for the production of renewable low-cost CFs. Additionally, the process generated an oily liquid phase with yields of ca. 10 wt% containing valuable catechol and methylated derivatives., RJW acknowledges financial support of the Fraunhofer Society and Fraunhofer Institute for Solar Energy Systems ISE through an “ATTRACT” award. PSS gratefully acknowledges the Spanish Ministry for Economy and Enterprise (MINECO) for a Ramón y Cajal fellowship (RYC-2014-16759) and a proyecto de I+D+I para jóvenes investigadores (MAT2014-59674-JIN). RJW and MO would also like to acknowledge the support of the joint Max Planck Society/Fraunhofer Society project “Dendrorefining”. Dr. H. Scherer (AK Krossing; University of Freiburg, Germany) is especially thanked for his assistance with NMR measurements. The authors would like to thank the ICTP-CSIC characterisation service for their help in measuring the DSCs of the samples. The Fraunhofer IAP (Potsdam, Germany) is thanked for assistance with GPC measurements.

Hierarchical H-ZSM-5 zeolites are a promising class of heterogeneous catalysts that have shown encouraging results in lab-scale studies for the production of gasoline from dimethyl ether (DTG conversion). However, the influences of mesopore formation and shaping on various catalyst properties are still under debate. In this study, a series of H-ZSM-5 zeolites with hierarchical pore structures were prepared by modifying commercially available zeolites via alkaline treatment ("desilication"). The powdered zeolites were shaped into technical catalyst bodies by wet extrusion using either silica or alumina binders. All materials were extensively characterized. The different interactions during alkaline treatment were related to the observed modifications in the zeolite properties of the materials obtained. Although many properties of modified and untreated zeolite powders remained predominantly unchanged in their shaped catalyst equivalents, both binders affected certain material characteristics, particularly those related to their acidity. Finally, preliminary tests showed enhanced catalytic performance of hierarchical ZSM-5 catalysts in DTG conversion.

Well-defined Pd/Ga-nanoparticles were prepared and used as a precursor for the methanol active component in a bifunctional syngas-to-dimethyl ether catalyst. In situ X-ray absorption spectroscopy experiments were employed both to unravel the initial formation of the active catalyst phase in reductive H 2 atmosphere and to further monitor changes of the nanoparticles under conditions of dimethyl ether synthesis at a pressure up to 20 bar (250 °C). The catalytic studies were conducted using simulated biomass-derived, CO-rich syngas in a continuous-flow reactor, with the bifunctional catalyst offering the two types of active sites, i.e. for methanol synthesis (Pd/Ga nanoparticles) and its subsequent dehydration (γ-Al 2 O 3 ), in close proximity. As compared to the conventional Cu/Zn-based reference catalyst prepared via a similar procedure, the Pd/Ga-based catalyst showed a promising activity together with a notable stability with time on stream and a high temperature tolerance (up to 300 °C). A kinetic model which considers the individual reactions involved in direct DME synthesis based on power law equations was used to fit the experimental data, and the apparent activation energies were compared to the Cu/Zn-based catalyst.

Hybrid catalysts were prepared using well-defined, colloidal Cu/Zn-based nanoparticles as building units. The nanoparticles were immobilized on acidic supports (i.e., γ-Al2O3, HZSM-5, and HY) to yield a series of bifunctional catalysts with a close proximity of active sites for both methanol synthesis and its further conversion to dimethyl ether (DME) or hydrocarbons (HCs). By this model kit principle, a high comparability of the bifunctional catalysts was ensured. The catalysts were characterized in depth regarding their structure and catalytic performance in the conversion of CO-rich synthesis gas. In situ XAS studies demonstrated the formation of the active phase under reducing conditions. The present study revealed important material parameters to control activity and selectivity of the bifunctional catalysts either towards DME or liquefied petroleum gas (LPG) products in the direct conversion of simulated biomass-derived synthesis gas. In particular, Cu loading, pore structure and Si:Al ratio were investigated.

Oligomeric oxymethylene dimethyl ethers (OMEs) of the type CH3O-(CH2O)n-CH3 are promising diesel fuels with an enormous potential for the reduction of soot and NOx emissions. Oligomers with n = 3–5 are particularly advantageous, since their physicochemical and combustion properties are similar to conventional diesel. OMEs can be produced from methanol and formaldehyde but a series of byproducts, especially hemiformals, glycols, water and minor amounts of cyclic ethers, are also formed. These need to be separated from the product mixtures, which affects efficiency of this synthesis pathway. To isolate the desired OMEs, a one-step synthesis/extraction procedure is described. It implies highly selective extraction of OMEs from aqueous reaction solutions employing hydrocarbons as extraction agents. If fuel-type hydrocarbons are used, the resulting OME-hydrocarbon blends can be directly used in fuel applications. The corresponding oxymethylene diethyl ethers (OMDEEs) have also been investigated. Compared to OMEs, OMDEEs exhibit an increased solubility in nonpolar media but, as a result, solubility of educts and byproducts also increases. OME blends with hydrogenated vegetable oil and diesel have been prepared containing 10% of OMEs. It could be shown that such blends meet current diesel standards to a large extent.

The life cycle energy consumption and greenhouse gas (GHG) emission performances of forest biomass-derived oxymethylene ether (OME) synthesis used as a diesel additive are analyzed in this study. OME, a new alternative liquid fuel, has great miscibility with conventional fuels like diesel. OME can reduce combustion emissions significantly when used as a diesel additive without any modification to the engine. A data-intensive spreadsheet-based life cycle assessment (LCA) model was developed for OME synthesis from woodchips derived from two different kinds of forest biomass, whole tree and forest residue. Woodchip harvesting, chip transportation, chemical synthesis of OME from biomass-derived syngas, OME transportation to blending, and vehicle combustion of this transportation fuel were considered in the system boundary. The results show that the whole tree pathway produces 27 g CO2eq/MJ of OME, whereas the forest residue pathway produces 18 g CO2eq/MJ of OME over 20 years of plant life. The difference is mainly due to some emissions-intensive operations involved in biomass harvesting and biomass transportation such as skidding, road construction, etc., in the whole tree pathway. Also, vehicle combustion was found to be the most GHG-intensive unit for both pathways. OME combustion in a vehicle accounts for about 77% and 83% of the total life cycle GHG emissions for the whole tree and forest residue pathways, respectively. This study also compares the diesel life cycle emission numbers with the life cycle emissions of OME derived from forest biomass, and it was observed that GHG emissions can be reduced by 20–21% and soot (black carbon) emissions can be reduced by 30% using a 10% OME blended diesel as a transportation fuel compared with conventional diesel.

A catalyst screening comprising zeolites and ion exchange resins for the synthesis of oligomeric oxymethylene dimethyl ethers (OME) from methanol (MeOH) and formaldehyde (FA) has been carried out. All catalysts led to the same product spectrum and parameters for chemical equilibrium have been determined. The ion exchange resin Dowex50Wx2 showed highest activity and reaction kinetics has been investigated employing this catalyst. The influence of the FA:MeOH ratio and water as well as refeeding of OMEs with undesired chain lengths have been considered in the kinetic model, which is based on a hyperbolic approach. Experiments have been carried out in the temperature range between 40 and 120 °C and variable FA:MeOH ratios from 0.5 to 1.5 g/g have been employed. Regarding water, up to 23 wt.% have been added to the reaction mixtures to investigate its influence on yield and reaction rate. Low water contents lead to high OME selectivities. By varying the FA:MeOH ratio, chain lengths of the OMEs can be influenced. Regarding the most active catalyst Dowex50Wx2, 90% of equilibrium conversion is reached after 5 min at 60 °C employing a catalyst loading of 1 wt.%. A study on the long term performance of the catalyst has been carried out and after 17 days the decrease of activity was below 10% while selectivity remained the same. For different Dowex catalysts a general kinetic model could be developed, which is not limited to Dowex50Wx2.

Oligomeric oxymethylene dimethyl ethers (OMEn, CH3(OCH2)nOCH3, n = 1 – 5) are promising diesel fuels for the reduction of harmful emissions. If OMEs are produced from dimethoxymethane and trioxane, the resulting OME mixtures usually contain residual trioxane which appears, after rectification, in the OME2 fraction. To circumvent this obstacle, substoichiometric amounts of trioxane have been employed in OME synthesis. Thus, OME2 samples with high purity could be prepared. Physicochemical and fuel data of high purity OME2 and higher OMEs have been determined to supplement previously reported data.

Hydrolysis of lignocellulosic biomass is a crucial step for the production of sugars and biobased platform chemicals. Pretreatment experiments in a semi-continuous plant with diluted sulphuric acid as catalyst were carried out to measure the time-dependent formation of sugars (glucose, xylose, mannose), furfurals, and organic acids (acetic, formic, and levulinic acid) at different hydrolysis temperatures (180, 200, 220 &deg, C) of one representative of each basic type of lignocellulose: hardwood, softwood, and grass. The addition of the acid catalyst is followed by a sharp increase in the sugar concentration. Xylose and mannose were mainly formed in the initial stages of the process, while glucose was released slowly. Increasing the reaction temperature had a positive effect on the formation of furfurals and organic acids, especially on hydroxymehtylfurfural (HMF) and levulinic acid, regardless of biomass type. In addition, large amounts of formic acid were released during the hydrolysis of miscanthus grass. Structural changes in the solid residue show a complete hydrolysis of hemicellulose at 180 &deg, C and of cellulose at 200 &deg, C after around 120 min reaction time. The results obtained in this study can be used for the optimisation of the hydrolysis conditions and reactor design to maximise the yields of desired products, which might be sugars or furfurals.

Aktuelle Trends aus der chemischen Prozesstechnik im Rahmen der Begleitforschung des Forschungsnetzwerkes Energie in Industrie und Gewerbe (EE4InG) werden vorgestellt. Wir gehen davon aus, dass die Trends zirkulare Wirtschaft und beschleunigte globalisierte Innovation (Modularisierung, Prozessintensivierung und Digitalisierung) bis 2030 auf die Chemieindustrie wirken. Die Technologieentwicklung anhand dieser Trends erlaubt es dem Chemieingenieurswesen, zukunftig entscheidende Beitrage zur Flexibilisierung und Defossilisierung der Wertschopfungsketten zu leisten.

Within the so-called bioliq® process, renewable carbon resources, especially agricultural residues, are converted to gasoline. The process chain comprises pyrolysis of the feedstocks, gasification to synthesis gas, gas cleaning and conversion of synthesis gas to dimethyl ether (DME) followed by conversion of DME to hydrocarbons. Construction of all process units has been completed now and the entire plant has been successfully operated in several campaigns. Thus, hundreds of liters of a new alternative gasoline are available now, which allow for an extensive testing. The basic characteristics of the resulting bioliq®/100 fuel are described. It is rich in aromatics and a blend consisting of 90 Vol.−% of conventional RON95 E5 fuel and 10 Vol.−% of bioliq®/100, designated as bioliq®/10, has been produced which meets the DIN EN 228 standard. Initial measurements on a single cylinder research engine have been carried out focusing on efficiency and emissions. A comparison of bioliq®/10 with neat RON95 E5 revealed an improved knocking behavior of bioliq®/10 even by a small fraction of regenerative bioliq® fuel. Particle as well as hydrocarbon emissions from bioliq®/10 are significantly higher than in the case of RON95 E5. Increased particle emissions are attributed to the higher content of aromatics. Soot reactivity has been investigated and soot from bioliq®/10 exhibits higher reactivity than soot from RON95 E5.

Gasification in supercritical water can be assisted with heterogeneous catalysts. Effective salt separation upstream of the catalyst is important to avoid poisoning of the catalyst and to recover nutrients. Recovery of phosphorus and nitrogen as well as gasification of a significant portion of the organic carbon were demonstrated on the pilot plant scale. A Ru/C catalyst was applied to catalyze the formation of CH4, which was the desired primary gasification product. On top of the catalyst, a bed of ZnO was used as sulfur adsorbent to protect the catalyst from deactivation. As feedstock for the process, glycerol, ethanol, and digestate sludge were studied. The results confirm the activity of the catalyst under the applied conditions. At a reaction temperature of 420 °C and a pressure of 280 bar, a gas composition close to thermodynamic equilibrium was achieved. Salt separation performed at 470 °C was effective, but the separation efficiency was less for potassium than for phosphorus. Fifty-six percent of the ash contained in digestate sludge was separated and recovered. Sulfur partly escaped the salt separation system and reached the reactor. The ZnO layer trapped most of this remaining sulfur. The remaining sulfur contamination was low enough not to poison the Ru/C catalyst completely. In total, 326 kg of glycerol, 334 kg of digestate sludge, and 167 kg of ethanol were gasified without any operational issues.

A methanol catalyst based on Cu/ZnO/Al 2 O 3 (CZA) was prepared and mixed with four different solid acids, a pure γ-Al 2 O 3 , a SiO 2 -doped γ-Al 2 O 3 , an AlPO 4 -doped γ-Al 2 O 3 and the zeolite H-MFI 400, respectively. These admixed catalyst systems were tested in the direct synthesis of dimethyl ether from CO-rich synthesis gas (CO:H 2 = 1), which is typical for biomass-derived synthesis gas. Reactions were carried out in a laboratory plant at 250 °C and 51 bar for 120 h time-on-stream followed by catalyst passivation with O 2 and regeneration by hydrogenation. After catalyst regeneration, the reaction was run again for another 72 h. The catalyst system containing the zeolite exhibited highest CO-conversion. However, all catalysts showed a drop of activity after the passivation- and regeneration-process and the system with the SiO 2 -doped γ-Al 2 O 3 showed the lowest loss of activity. Investigation of the catalysts after reaction by N 2 O-pulse chemisorption and XRD revealed that agglomeration of catalyst species took place leading to an increased Cu 0 -particle size for all systems. This phenomenon was less pronounced in the case of the system containing the SiO 2 -doped γ-Al 2 O 3 . Thus, the main cause of catalyst deactivation was found to be sintering of the catalytically active components.

Fast pyrolysis is the first step of the bioliq concept, which is developed at the Karlsruhe Institute of Technology (KIT) together with Air Liquide (Lurgi Technologies) for synthetic fuel production from lignocellulosic biomass via gasification. In the 2 MW bioliq fast pyrolysis pilot plant, shredded wheat straw is mixed with a hot heat carrier (sand) in a twin screw mixer reactor. At a temperature of 500 °C and in the absence of oxygen, the biomass particles are rapidly decomposed within seconds and pyrolysis gas, solids, and organic and aqueous condensates are produced. Representative results of the product yields and properties obtained from selected pyrolysis test campaigns from 2013 to 2015 are presented. It is shown that the mass ratio between the two liquid condensates can be adjusted by appropriate process design and operating conditions. Product stability is discussed, giving evidence that, by process internal recycling of the organic condensate, a controlled thermal maturing can be performed. It...

Modeling of fast pyrolysis reactors is challenging, even with state of the art computational tools and design, because rules to scale up well-running fast pyrolysis reactors are missing. Dimensional analysis is a classical tool to evaluate complex processes on a scientific basis and its application to fast pyrolysis is presented herein. Using the example of auger-type fast pyrolysis reactors, it is shown that scale-up can be reduced to a set of simple design rules. Full similarity of reaction conditions can never be achieved for fast pyrolysis in general, but it is shown which similarities are affected and to which extent they change. Dimensionless numbers derived from this analysis can even be used to describe the influence of parameters on the reactor performance; however, a significant reduction in complexity is required to achieve a practical relevance list. Strategies are outlined to achieve such a reduction based on partial similarities of rate-determining steps.

The conversion of biomass for the production of liquid fuels can help reduce the greenhouse gas (GHG) emissions that are predominantly generated by the combustion of fossil fuels. Oxymethylene ethers (OMEs) are a series of liquid fuel additives that can be obtained from syngas, which is produced from the gasification of biomass. The blending of OMEs in conventional diesel fuel can reduce soot formation during combustion in a diesel engine. In this research, a process for the production of OMEs from woody biomass has been simulated. The process consists of several unit operations including biomass gasification, syngas cleanup, methanol production, and conversion of methanol to OMEs. The methodology involved the development of process models, the identification of the key process parameters affecting OME production based on the process model, and the development of an optimal process design for high OME yields. It was found that up to 9.02 tonnes day−1 of OME3, OME4, and OME5 (which are suitable as diesel additives) can be produced from 277.3 tonnes day−1 of wet woody biomass. Furthermore, an optimal combination of the parameters, which was generated from the developed model, can greatly enhance OME production and thermodynamic efficiency. This model can further be used in a techno-economic assessment of the whole biomass conversion chain to produce OMEs. The results of this study can be helpful for petroleum-based fuel producers and policy makers in determining the most attractive pathways of converting bio-resources into liquid fuels.

The hydrothermal base-catalysed treatment of industrial Kraft lignin (KL) is investigated as a basis for production of a sustainable carbon fibre precursor, with a focus on the time-dependent evolution and impact on precursor properties. Hydrothermal treatment was performed at T = 300 °C and p = 180 bar, with the retention time (t) varied between 8, 12, 16, 20, and 24 mins. Molecular weight distribution and thermal stability of the processed lignin were close to maximum after 8 min, and 12–16 min respectively. Chemical modification was found to continue (e.g. demethoxylation) over the entire t range (24 min). Analysis of the recovered oily phase indicated catechol derivatives were stable end-products with, e.g., vanillin and guaiacol as intermediates. A techno-economic analysis indicated a price of ca. 1600 €/t at a production capacity of 10 kt/a is achievable, with main cost-drivers being lignin (60%), fixed costs (20%), and energy (10%)., RJW acknowledges financial support of the Fraunhofer Society and Fraunhofer Institute for Solar Energy Systems ISE through an “ATTRACT” award. PSS gratefully acknowledges the Spanish Ministry for Economy and Enterprise (MINECO) for a Ramón y Cajal fellowship (RYC-2014-16759) and a proyecto de I+D+I para jóvenes investigadores (MAT2014-59674-JIN). RJW and MO would also like to acknowledge the support of the joint Max Planck Society/Fraunhofer Society project “Dendrorefining”. Dr. H. Scherer (AK Krossing; University of Freiburg, Germany) is thanked for his assistance with NMR measurements. The authors would like to thank the ICTP-CSIC characterisation service for their help in measuring the DSCs of the samples. The Fraunhofer IAP (Potsdam, Germany) is thanked for assistance with GPC measurement

The gasification of microalgae in supercritical water was investigated in this work. The product gas contained mainly H2, CO2, CH4, and C2H6. Operation at high temperatures and lower biomass concentrations resulted in the highest carbon gasification efficiency and the lowest total organic carbon levels in the residual water. Due to its content of inorganic nutrients, the residual water was applied as cultivation medium for microalgae. However, algal growth in the untreated residual water was inhibited by the existence of potentially toxic substances evolved from gasification. Upon treatment by activated carbon filtration and ultraviolet light degradation, these substances were eliminated and cultivation in the residual water was possible. The major fraction of inorganic residues from gasification was recovered by means of water purging, increasing the potential of nutrient recycling for cultivation.

Well-defined colloidal Cu/Zn-based nanoparticles were synthesized and employed as precursors for the methanol active component in bifunctional syngas-to-dimethyl ether (STD) catalysts. The experiments were conducted using simulated biomass-derived, CO-rich syngas (H2 : CO ratio of 1 : 1) in a single continuous-flow reactor by combining the two catalytically active components (i.e., Cu/ZnO for methanol synthesis and γ-Al2O3 for its subsequent dehydration). Two different synthetic pathways were developed for synthesizing the colloidal Cu/Zn-based nanoparticles, while ensuring close contacts between the Cu nanoparticles and the Zn phase. Pure Cu nanoparticles were used as a reference. A series of bifunctional STD catalysts was prepared, where the nanoparticles were either directly supported on the dehydration catalyst or integrated into the STD catalyst by physical mixing. With this approach, active catalysts for the STD reaction with high DME selectivity were obtained.

The majority of platform chemicals are currently provided through crude oil processes. Nevertheless, the substitution of the crude oil with biomass should be the ecological aim. Lignin, an aromatic macromolecule, may play an important role in that exchange, as it is the only bio based source of aromatic compounds. For instance, it could be a source of bifunctional aromatic molecules, like the monocyclic compounds catechol or guaiacol, or bifunctional oligomers. However, no process for the production of aromatics from lignin in technical scale has been established until now. Hence, the focus of this work is to clarify the chemical degradation mechanism under hydrothermal conditions, to liquefy lignin delivering high functional molecules and to increase the yield and selectivity of the cleavage towards bifunctional molecules like catechol. The combination of fast hydrolysis, thermal degradation reactions and hydrogenation drives the hydrothermal liquefaction; this gives the possibility to narrow down the product spectrum in comparison to other “dry” cleavage methods, towards a higher yield of e.g. catechols.

Renewable fuels from biomass have to be produced in large facilities to profit from the economy of scale. Unfortunately, most biomass residues have only a low energy density and are collected in wide areas, which hampers the transport to a large central conversion plant. Therefore, energy densification is a crucial point which can be achieved by thermochemical process like fast pyrolysis, yielding liquid bio-oil and solids consisting of char and ash. High energy densities can be obtained by mixing of the solid and liquid conversion products to produce bio-slurries also referred to as biosyncrude. In the bioliq® process, these liquid-like suspensions are used as feed for high pressure entrained flow gasification and downstream synthesis of fuels and chemicals. The article describes the mixing process of bio-slurries and the most relevant parameters, which have to be taken into consideration. The materials used are mainly derived from the pyrolysis of beech wood, wheat straw, and oil palm residues, but also model mixtures of char with ethylene glycol and water show principal features of the bio-slurries. Small char particles with low porosity promote flowability of the bio-slurry and stability with regard to sedimentation, but also examples are worked out, where liquid–liquid phase separation have negative influence of the handling of bio-slurries. The power consumption of the bio-slurry production and the viscosity of a bio-slurry depend highly on the selected technologies by which deagglomeration and milling is carried out. A successful bio-slurry preparation results in a flowable suspension of at least reasonable stability with an energy content of > 85% of the energy of the biomass feedstock.

Fast pyrolysis is being increasingly applied in commercial plants worldwide. They run exclusively on woody biomass, which has favorable properties for conversion with fast pyrolysis. In order to increase the synergies of food production and the energetic and/or material use of biomass, it is desirable to utilize residues from agricultural production, e.g., straw. The presented method is suitable for converting such a material on an industrial scale. The main features are presented and an example of mass balances from the conversion of several biomass residues is given. After conversion, fractionated condensation is applied in order to retrieve two condensates - an organic-rich and an aqueous-rich one. This design prevents the production of fast pyrolysis bio-oil that exhibits phase separation. A two phase bio-oil is to be expected because of the typically high ash content of straw biomass, which promotes the production of water of reaction during conversion. Both fractionated condensation and the use of biomass with high ash content demand a careful approach for establishing balances. Not all kind of balances are both meaningful and comparable to other results from the literature. Different balancing methods are presented, and the information that can be derived from them is discussed.

Experiments with a process development unit for fast pyrolysis of biomass residues of 10kgh(-1) have been performed to quantify the impact of two different product recovery options. Wheat straw, miscanthus and scrap wood have been used as feedstock. A separate recovery of char increases the organic oil yield as compared to a combined recovery of char and organic condensate (OC). Furthermore, it allows for an alternative use of the byproduct char which represents an important product fraction for the high ash biomass residues under consideration. The char produced shows little advantage over its biomass precursor when considered as energy carrier due to its high ash content. Significant value can be added by demineralizing and activating the char. The potential to increase the economic feasibility of fast pyrolysis is shown by an assessment of the bioliq® process chain.