Low-grade Feedstock Research Articles

Near-Critical CO2-Assisted Liquefaction-Extraction of Biomass and Wastes to Fuels and Value-Added Products

Abstract With the growing need for sustainable carbon-neutral liquid fuels, low-grade feedstocks, such as lignocellulosic biomass, and municipal solid wastes offer sufficient potential via thermochemical conversion. But the existing thermochemical means are limited in feed flexibility and scalability and require significant processing (energy and costs) of the intermediates. Bio-oil/biocrude intermediate from fast pyrolysis and hydrothermal techniques is impeded by issues of stability and oxygen content, along with hydrotreating viability. To address these issues, we investigated a novel pathway of near-critical CO2-assisted integrated liquefaction-extraction (NILE) technology in conceptual aspects for conversion of various biomass and municipal solid wastes into high-quality biocrude with high compatibility for co-hydrotreating with traditional fossil crude for liquid fuel needs in power and transportation sectors. Using supercritical CO2 for dewatering wet feedstocks, for liquefaction, and extraction for lighter biocrude has produced biocrude with lower oxygen content by 50%, lowered metal content by 90%, stable viscosity, low acidity, and good aging stability compared to that produced from hydrothermal liquefaction along with higher hydrotreating and co-hydrotreating compatibility. Hydrotreating of the biocrude extract from supercritical CO2 extraction also was feasible with no detected coke deposition, an oxygen content of 1%, and catalyst deactivation. The validation and capabilities of the NILE concept urge for its further development to obtain sustainable liquid fuels with lower greenhouse gas emissions and costs.

Polyhydroxybutyrate (PHB) Biosynthesis by an Engineered Yarrowia lipolytica Strain Using Co-Substrate Strategy

High production cost is one of the major factors that limit the market growth of polyhydroxyalkanoates (PHAs) as a biopolymer. Improving PHA synthesis performance and utilizing low-grade feedstocks are two logical strategies for reducing costs. As an oleaginous yeast, Y. lipolytica has a high carbon flux through acetyl-CoA (the main PHB precursor), which makes it a desired cell factory for PHB biosynthesis. In the current study, two different metabolic pathways (NBC and ABC) were introduced into Y. lipolytica PO1f for synthesizing PHB. Compared to the ABC pathway, the NBC pathway, which includes NphT7 to redirect the lipogenesis pathway and catalyze acetoacetyl-CoA synthesis in a more energy-favored reaction, led to PHB accumulation of up to 11% of cell dry weight (CDW), whereas the ABC pathway resulted in non-detectable accumulations of PHB. Further modifications of the strain with the NBC pathway through peroxisomal compartmentalization and gene dose overexpression reached 41% PHB of CDW and a growth rate of 0.227 h−1. A low growth rate was observed with acetate as the sole source of carbon and energy or glucose as the sole substrate at high concentrations. Using a co-substrate strategy helped overcoming the inhibitory and toxic effects of both substrates. Cultivating the engineered strain in the optimal co-substrate condition predicted by response surface methodology (RSM) led to 83.4 g/L of biomass concentration and 31.7 g/L of PHB. These results offer insight into a more cost-effective production of PHB with engineered Y. lipolytica.

Powdered Hierarchically Porous Silica Monoliths for the Selective Extraction of Scandium.

Scandium (Sc) is a high value Critical Material that is most commonly used in advanced alloys. Due to current and potential supply limitations, there has been an international effort to find new and improved ways to extract Sc from existing and novel resources. Solid-phase extraction (SPE) is one promising approach for Sc recovery, particularly for use with low-grade feedstocks. Here, unfunctionalized, powdered hierarchically porous silica monoliths from DPS Inc. (DPS) are used for Sc extraction in batch and semicontinuous flow systems at model conditions. The sorbent exhibits excellent mass transfer properties, much like the whole monoliths, which should permit Sc to be rapidly recovered from large volumes of feedstock. The Sc adsorption capacity of the material is ∼142.7 mg/g at pH 6, dropping to ∼12.0 mg/g at pH 3, and adsorption is furthermore highly selective for Sc compared with the other rare earth elements (REEs). Under semicontinuous flow conditions, recovery efficiency is limited by a kinetic process. The primary mechanism responsible for the system's slow approach to equilibrium is the Sc adsorption reaction kinetics rather than inter- or intraparticle diffusion. Overall, this unmodified hierarchically porous silica powder from DPS shows great promise for the selective extraction of Sc from various feedstocks.

Separation of Rare-Earth Elements by Supported Liquid Membranes: Impacts of Soluble Iron, Aluminum, and pH in Low-Grade Feedstocks

Separation of Rare-Earth Elements by Supported Liquid Membranes: Impacts of Soluble Iron, Aluminum, and pH in Low-Grade Feedstocks

Lanmodulin-Functionalized Magnetic Nanoparticles as a Highly Selective Biosorbent for Recovery of Rare Earth Elements.

Recovering rare earth elements (REEs) from waste streams represents a sustainable approach to diversify REE supply while alleviating the environmental burden. However, it remains a critical challenge to selectively separate and concentrate REEs from low-grade waste streams. In this study, we developed a new type of biosorbent by immobilizing Lanmodulin-SpyCatcher (LanM-Spycatcher) on the surface of SpyTag-functionalized magnetic nanoparticles (MNPs) for selective separation and recovery of REEs from waste streams. The biosorbent, referred to as MNP-LanM, had an adsorption activity of 6.01 ± 0.11 μmol-terbium/g-sorbent and fast adsorption kinetics. The adsorbed REEs could be desorbed with >90% efficiency. The MNP-LanM selectively adsorbed REEs in the presence of a broad range of non-REEs. The protein storage stability of the MNP-LanM increased by two-fold compared to free LanM-SpyCatcher. The MNP-LanM could be efficiently separated using a magnet and reused with high stability as it retained ∼95% of the initial activity after eight adsorption-desorption cycles. Furthermore, the MNP-LanM selectively adsorbed and concentrated REEs from the leachate of coal fly ash and geothermal brine, resulting in 967-fold increase of REE purity. This study provides a scientific basis for developing innovative biosorptive materials for selective and efficient separation and recovery of REEs from low-grade feedstocks.

Desulfurization of biodiesel produced from waste fats, oils and grease using β-cyclodextrin

Making biodiesel from the fat, oil and grease in wastewater is attractive for sustainable biofuel production, waste management and public health. Sulfur reduction is a critical problem in biofuel production from low grade feedstocks containing high levels of sulfur contamination. Traditional desulfurization methods face challenges due to the financial and environmental costs of required catalysts, reagents or energy.This paper presents a new desulfurization method applied to biodiesel that uses β-cyclodextrin as the adsorbent. Biodiesel was produced from brown grease decanted from the FOG delivered to a local wastewater treatment plant. The equilibrium and kinetic behavior of the adsorption process were quantified with experimental measurements using the produced biodiesel and commercially available β-CD. A convection/diffusion model was then developed to simulate the adsorption process in a fixed bed adsorber. A 3-column design is presented based on the model results and compared with a sulfur reduction system based on vacuum distillation.The β-CD system operates at ambient temperature and pressure, whereas the vacuum distillation system operates at less than 0.01 Atm and near 200 C. The initial cost of the β-CD system is expected to be less than half the cost of the distillation system, but the operating costs may be similar. The β-CD system does not require the addition of hydrogen as in hydrodesulfurization but does require regeneration and periodic replacement of β-CD. Process intensification strategies such as polymerizing the β-CD or using more innovative process designs than fixed bed adsorbers may further increase the advantages of a β-CD based desulfurization system.

High Temperature Winkler gasification of Rhenish lignite in an optimized 500 kWth pilot plant

Gasification processes are an important part of a broad variety of value chains from low grade feedstocks to energy. The process considered in this work consists of a 0.5 MWth fluidized bed gasifier, a gas cleaning unit and a catalyst test rig. This paper presents experimental results from the stand-alone operation of the gasifier in order to investigate the behavior of the gasification of two feedstocks, a dried lignite steam coal and a commercially available low sulfur, low ash lignite. Furthermore, the results of the gasification of the gasifier start-up material hearth furnace coke are given. The reactor with a height of 11 m and an inner diameter of 400 mm was operated at up to 870 °C. Carbon dioxide, steam and oxygen can be introduced into the reactor through different nozzle levels.Four test campaigns were conducted and seven balance points with different feedstock and loads were investigated. The results show carbon conversions of almost 96 % and cold gas efficiencies up to 65 % with coal from fluidized bed drying showing the highest cold gas efficiencies and carbon conversions. Several trace gases were measured by Fourier-Transform Infrared Spectroscopy and a positive correlation between benzene and methane concentration is detected.The experience gained serves as a basis for the gasification step in the polygeneration process and for gasification of other feedstock, especially biogenic and anthropogenic residues.

Non-catalytic and glycerol-free biodiesel production from rice bran oil fatty acid distillate in a microreactor

Obtained from rice bran oil refining process, rice bran oil fatty acid distillate (RBOFAD) is a low-value, non-edible, and unwanted by-product, which can be used as a promising alternative raw material for biodiesel production. However, the conventional biodiesel process cannot handle this material due to the high content of free fatty acid (FFA). A novel supercritical process for biodiesel synthesis using dimethyl carbonate (DMC) as acyl acceptor in a microreactor was proposed in this work for the raw material with high FFA. High quality of biodiesel and value-added by-product (glyoxal) were obtained in our process. In this process, the biodiesel content of 80.9% was achieved for the case of RBOFAD as feedstock, compared to only 43.6% for the case of refined rice bran oil as feedstock. The influence of operating conditions on biodiesel and glyoxal content including reaction temperature, residence time, and DMC-to-RBOFAD molar ratio was investigated and optimized via response surface methodology. The biodiesel content of 97.1% was achieved at the optimal conditions (reaction temperature of 360 °C, residence time of 35 min, and RBOFAD-to-oil molar ratio of 11:1). The required pressure and the amount of DMC were significantly reduced compared to other processes. Most of the biodiesel properties met the international standards except for some impurities (mono- and diglycerides). These results provided the new insight for the development of biodiesel production from low-grade feedstocks.

Numerical forecast of redzone extension in cast silicon ingots in dependence on the purity level of crucible, coating and feedstock

The extension of the areas with extremely low minority carrier lifetime in cast silicon ingots for photovoltaic application is a crucial parameter for the industrial manufacturers determining the yield of the grown Si ingot material usable for solar cell fabrication. In order to make a forecast of this redzone extension in dependence on the purity levels of the consumables like crucible, Si3N4-coating and Si-feedstock, a numerical 2D model was used to investigate the diffusive iron (Fe) incorporation into the silicon during the directional solidification process. In order to set up this model, the diffusion parameters of Fe in crucible and Si3N4-coating were determined by 1D numerical analysis of annealing experiments. These values were used in a 2D model to simulate several G1 experiments with varying Fe impurity levels of all crucible consumables (SiO2-crucible and internal Si3N4-coating). The 2D model was validated through comparison of the calculated and experimentally observed redzone.The 2D model was scaled up to the industrial G6 dimensions and a forecast of redzone extension considering the use of the same consumables was set up. The results show that as long as the influence of conventional silica ceramic crucibles is present, the use of Si3N4-coatings or Si feedstock with higher purity will show no positive effect on the redzone extension. For setups without impact of the crucible, similar to current setups including a diffusion barrier, and high silicon feedstock purity, the Si3N4-coating becomes the dominating Fe contamination source. At the same time, the effect of high purity Si3N4-coatings becomes negligible, when the assumed Fe concentration level of the silicon feedstock exceeds values expected for aggressive blending scenarios or low grade feedstock scenarios, which could be motivated by an aggressive cost down attitude.

Microbe-Encapsulated Silica Gel Biosorbents for Selective Extraction of Scandium from Coal Byproducts.

Scandium (Sc) has great potential for use in aerospace and clean energy applications, but its supply is currently limited by a lack of commercially viable deposits and the environmental burden of its production. In this work, a biosorption-based flow-through process was developed for extraction of Sc from low-grade feedstocks. A microbe-encapsulated silica gel (MESG) biosorbent was synthesized through sol-gel encapsulation of Arthrobacter nicotianae, a bacterium that selectively adsorbs Sc. Microscopic imaging revealed a high cell loading and macroporous structure, which enabled rapid mass transport and adsorption/desorption of metal ions. The biosorbent displayed high Sc selectivity against lanthanides and major base metals, with the exception of Fe(III). Following pH adjustment to remove Fe(III) from an acid leachate prepared from lignite coal, a packed-bed column loaded with the MESG biosorbent exhibited near-complete Sc separation from lanthanides; the column eluate had a Sc enrichment factor of 10.9, with Sc constituting 96.4% of the total rare earth elements. The MESG biosorbent exhibited no significant degradation with regard to both adsorption capacity and physical structure after 10 adsorption/desorption cycles. Overall, our results suggest that the MESG biosorbent offers an effective and green alternative to conventional liquid-liquid extraction for Sc recovery.

Development of lignin based heterogeneous solid acid catalyst derived from sugarcane bagasse for microwave assisted-transesterification of waste cooking oil

The production of biodiesel by using homogeneous or heterogeneous catalysts is not favourable due to difficult catalyst recovery, purification of the product in case of homogeneous catalysts and longer reaction time, severe reaction conditions and high production cost are the drawbacks of heterogeneous catalysts. Different sulfonated catalysts were synthesized to overcome these problems and their feasibility on industrial scale. Therefore, the focus of this study was to synthesize a sulfonated catalyst using activated carbon produced from the lignin extracted from sugarcane bagasse and used in the transesterification of waste cooking oil with methanol using microwave as heating source. The catalyst was prepared by varying the sulfonation temperature (140–220 °C) for 120 min and characterized by using thermogravimetric analysis (TGA), scanning electron microscope (SEM), fourier transform infrared spectroscopy (FT-IR), surface area (BET) and elemental analysis by CHNS analyzer. The catalyst prepared at 180 °C for 2 h showed excellent characteristics in terms of surface area i.e., 30.31 m2. g−1, acidic density 4.74 mmol. g−1, pore volume 0.03 cm3 g−1, pore size of 9.44 nm, functional groups attachments, surface morphology and crystallographic structure. The process of transesterification was optimized by varying reaction time (5–25 min), methanol to oil molar ratio (6:1–24:1), catalyst loading (5–20 wt% to oil) and temperature (40–70 °C). The maximum yield (89.19%) of biodiesel was achieved after 15 min with a methanol to oil molar ratio of 18:1 at 60 °C and 15 wt% of catalyst. The reusability and stability of the prepared catalyst up to six cycles with minor loss in its activity i.e., 8% for low-grade feedstocks having higher value of free fatty acid content (FFA) was studied.

Biodiesel production from transesterified waste cooking oil by zinc-modified anthill catalyst: Parametric optimization and biodiesel properties improvement

Biodiesel, an unconventional fuel to substitute the existing fossil diesel, is non-toxic, biodegradable, possesses high lubricity and better combustion capacity. In this paper, a new eco-friendly solid catalyst was developed from anthill-zinc modification for methanolysis of low-grade feedstock (waste cooking oil, WCO) to make biodiesel. The zinc-modified anthill was prepared via the sol-gel technique and characterized by EDX, TGA/DTA, FTIR, XRD, SEM, BET and CO2-TPD. The optimum experimental conditions obtained by a central composite design were 17.99:1, 0.51 wt%, and 66.54 °C for the molar ratio of methanol to WCO, catalyst loading and reaction temperature, respectively. At these optimum values, the highest experimentally obtained biodiesel yield was 83.16%, which matched the predicted value (82.71%) reasonably well with R2 = 0.9914. According to gas chromatography analysis, the fatty acid methyl ester conversion under optimum conditions was 97.05%. While 20% blending of biodiesel on a volume basis with petroleum-based diesel showed remarkable fuel properties, the catalyst exhibited better stability after being regenerated and reused for six cycles. This study extends the frontier of knowledge in the economical production of biofuels from waste products.

Process optimization of biodiesel production via esterification of oleic acid using sulfonated hierarchical mesoporous ZSM-5 as an efficient heterogeneous catalyst

The development of effective heterogeneous catalysts for the production of biodiesel from low-cost feedstocks containing large amounts of free fatty acids has lately become one of the foremost research issues in the energy research area. Herein, hierarchical mesoporous ZSM-5 zeolite containing sulfonic acid groups (SO3H-HM-ZSM-5-3) was prepared via the hard template approach, using soluble starch as a cheap and sustainable mesoporegen, and the subsequent sulfonation using chlorosulfonic acid as a sulfonating agent. The catalytic activity of the synthesized catalyst was evaluated in the esterification of oleic acid with methanol, and the principal process variables were optimized, adopting the response surface methodology. Results revealed that the catalyst amount and reaction temperature seemed to be the most influential variables governing the esterification process. A maximum oleic acid conversion of 100% was achieved under the optimum operating conditions of 18:1 methanol-to-oleic acid molar ratio and 5.2 wt% catalyst amount (based on the mass of oleic acid) at 88 °C, for 10 h. The performance of the developed SO3H-HM-ZSM-5-3 catalyst was comparable to or even outperformed some other reported acidic catalysts. Importantly, the performance of SO3H-HM-ZSM-5-3 for biodiesel production from waste cooking oil doped with 15% of oleic acid was additionally explored, and methyl ester yield as high as 92.45% was achieved through the simultaneous esterification of free fatty acids and the transesterification of triglycerides. Accordingly, SO3H-HM-ZSM-5-3 appears promising as an industrial catalyst for the one-step biodiesel production from low-grade feedstocks containing high levels of FFAs.

Silica-Based Solid Acid Catalyst with Different Concentration of H2SO4 and Calcination Temperature: Preparation and Characterization

Silica-based solid acid catalysts have been successfully prepared and characterized. This research aimed to study the effect of sulfuric acid and calcination temperature on the properties of silica-based solid acid catalyst chemically and physically. The catalyst was synthesized with tetraethyl ortho silicate (TEOS) as precursor of SiO2 through the sol gel method using sulfuric acid (H2SO4) with various concentrations (1 M, 2 M, and 3 M). Next, the gel formed was calcined with various temperatures (500, 600, 700, 800, and 900 °C). The synthesized sample was then tested for total acidity determination and was characterized using various instrumentations: FTIR, XRD, Gas Sorption Analyzer (GSA), and SEM. The total acidity increased with the increasing acid concentration and calcination temperature up to 700 °C. The N2 adsorption-desorption data showed a relatively large surface area 410,97 m2/g which can provide space for catalytic reaction for fatty acids. The catalytic study was carried out for esterification reaction using reflux system to reduce free fatty acids (FFA) content up to 49% and be possibly to be selected as pretreatment step for low grade feedstock biodiesel conversion.

Two-step sub/supercritical water and ethanol processes for non- catalytic biodiesel production

The catalyst-free two-step process has been developed for biodiesel production using low-grade feedstocks. The first step consists of triglycerides hydrolysis under subcritical water conditions to generate and increase free fatty acid (FFA) content for ethyl ester production. In its subcritical state, water can be used as both a solvent and a reactant for the hydrolysis of triglycerides. The hydrolyzed product mixture is separated by decantation into the oil phase of FFA (upper layer) and a water phase that contains glycerol (lower layer). In the second step, the hydrolyzed products of free fatty acids were successfully esterified to their ethyl ester in supercritical ethanol conditions without any catalyst. Under the sub- and supercritical conditions of water and ethanol, the hydrolysis and the esterification reactions proceed quickly, with a conversion of greater than 98 % after 10−20 min. This two-step process for biodiesel production offers several advantages, such as milder reaction conditions and pollution reduction due to the use of water instead of organic solvents. Also, the glycerol is removed after the hydrolysis reaction so that the backward reaction between the glycerol and the ethyl ester disappears, and lead to the biodiesel yield and quality improvement. The aim of this study is making a comparison between our previous one-step process and the two-step reaction process to find the best pathway for designing and building an integrated reactor. Indeed, the two-step process is more applicable for low-grade feedstocks with a high amount of FFA and water.

Continuous catalyst-free biodiesel synthesis from rice bran oil fatty acid distillate in a microreactor

This work proposed the catalyst-free biodiesel synthesis from the low-grade feedstock. Rice bran oil fatty acid distillate (RBOFAD) containing 65.5% of free fatty acids and ethanol were applied as a feedstock. The influence of operating parameters including residence time, reaction temperature, and ethanol-to-oil molar ratio on the biodiesel content (%Ester) were investigated. The experiments were carried out in a microreactor under the supercritical conditions. It was found that all parameters were important for achieving high %Ester. The optimal conditions for obtaining high biodiesel content (75%) were as follows: reaction temperature of 300 °C, ethanol-to-oil molar ratio of 5:1, and residence time of 24 min. The potential enhancement of this synthesis was studied through the addition of either iso-propanol or acetic acid which acted as a co-reactant. Unfortunately, both additives did not increase the %Ester further over the range of operating conditions studied.

Solidification processing of scrap Al-alloys containing high levels of Fe

The accumulation of iron in molten aluminium is one of the main concerns for the recycling and casting industries because it leads to the formation of undesirable Fe-rich intermetallic compounds which are detrimental to mechanical properties. Many methods have been developed in the past to reduce the iron accumulated in molten aluminium scrap, but they all suffer from poor efficiency. Hence, a more efficient method is urgently needed to mitigate the negative effect of high iron levels in the melt, thereby avoiding downgrading secondary aluminium to low quality products or the dilution with expensive primary aluminium. This contribution provides a study of the Fe-rich intermetallic compounds developed in aluminium casting alloys with high levels of Fe as a function of melt processing conditions. Results show that the formation of the Fe-compounds is not only dependent on the cooling rate and holding time before solidification, but more on the initial melt treatment as it enhances the nucleation and growth of the Fe-phases. Elemental addition of Mn leads to the formation of large and compact intermetallic particles, but at slow rate. Physical melt treatment by intensive high shearing produces a much faster nucleation and results in a fine dispersion of smaller iron containing intermetallic particles. The latter could be used either to increase the tolerance to iron contamination or to facilitate the iron removal process, providing huge benefits for the recyclability of scrap aluminium alloys as it would allow the transformation of low-grade feedstock into a low cost and small carbon footprint material for high quality castings.

Optimization of oil extraction from Leucaena leucocephala seed as an alternative low-grade feedstock for biodiesel production

Optimization of oil extraction from Leucaena leucocephala seeds (LLS) using solvent method was studied. 2k factorial technique was employed for optimization of extraction process variables, which include particle size, extraction temperature, extraction time and solvent/solid ratio. Good agreements were achieved between the predicted and experimental values of oil extraction yield $$\left( {{\text{R}}^{2} = 0.9974\,{\text{and}}\,{\text{Adj-R}}^{2} = 0.9922} \right)$$ . Optimization results showed that maximum oil extraction efficiency was achieved under the optimized factor combination of ≤ 0.6 mm particle size, 50 °C extraction temperature, 2 h extraction time and 10:1 v/w solvent/solid ratio.

Advancement in the Utilization of Nanocatalyst for Transesterification of Triglycerides

Biofuels are emerging as an alternative fuel to replace the conventional one. Biodiesel production is carried out by the transesterification process where catalyst plays an important role in the production of biodiesel. The reaction is catalyzed by either homogeneous catalyst or heterogeneous catalyst as the selection of suitable catalyst depends upon the amount of free fatty acid present in oil. Since past few decades focus was made on homogeneous catalyst for the production of biodiesel but slowly the trend has been changed as heterogeneous catalyst is becoming more promising catalyst for the production of biodiesel due to its properties which can overcome the problems faced by the homogeneous catalyst. Heterogeneous catalysts have been effective way to produce biodiesel but has drawback of being sensitive to free fatty acids (FFA) and low grade feed stock. This paper gives overview of the production of biodiesel with different heterogeneous catalyst consisting of carbon catalyst such as CaO based catalyst, carbon nano tubes (CNT) and graphene oxide (GO), activated carbon and solid acid catalyst. The utilization of heterogeneous catalyst provides a greener and cheaper synthesis of production of biodiesel.

Entrained flow gasification. Part 3: Insight into the injector near-field by Large Eddy Simulation with detailed chemistry

Entrained flow gasification is a promising process for the conversion of low-grade feedstock, e.g. highly viscous slurries and suspensions with a significant content of solid particles, to high quality fuels. A major scientific challenge is the prediction of the physical and chemical phenomena occurring in such high-temperature and high-pressure multiphase flow systems. In this context, this article is the sequel to “Entrained flow gasification. Part 1: Gasification of glycol in an atmospheric-pressure experimental rig ” [1] and “Entrained flow gasification. Part 2: Mathematical modeling of the gasifier using RANS method ” [2]. The same strategy as in the first two parts was followed. In order to reduce complexity, this study focused on a two-phase (gas and liquid) flow system with a model fuel (mono-ethylene glycol) under the simplified conditions provided by the atmospheric lab-scale gasifier REGA. Using the experimental data set provided in Part 1 of the coordinated papers for validation purposes, the main focus of this study was on the detailed understanding of the near injector region of the entrained flow gasifier REGA. The unsteady flow and the chemical conversion in the gasifier were investigated by means of Large Eddy Simulations with a detailed chemistry solver including 44 individual species and a direct calculation of 329 chemical reactions. The dispersed phase was solved by Lagrangian Particle Tracking. Downstream comparisons with experimental data showed a reasonable agreement concerning temperature and species profiles. The analysis of the injector near-field revealed that the high temperature reaction zone close to the injector could not be explained by a direct reaction of the fuel with the oxidizer. Instead, carbon monoxide and hydrogen mainly formed on the axis were transported upstream by the recirculation zone. The reaction of CO and H2 with the oxygen stabilized the flame. The heat release from this reactions supported the vaporization and decomposition of fuel as well as the downstream gasification reactions.