Analysis of the production process and proposals for its streamlining

Tato bakalářská práce vznikla za účelem analýzy a následné optimalizaci výrobního procesu. Cílem bylo docílit nižších provozních nákladů procesu a navýšit výrobní kapacitu. Teoretická část se zabývá procesním řízením, štíhlou výrobou, způsoby, které odstraňují plýtvání a nástroji k řízení efektivity výrobního procesu. Praktická část ze zabývá analýzou současného stavu výrobního procesu. Na základě této analýzy bylo navrženo nové řešení výrobního procesu, které zvyšuje jeho efektivitu. Závěrem je možné rozpoznat nežádoucí druhy plýtvání, které mají vliv na výkonnost podniku.ObhájenoThis bachelor thesis was created for the purpose of analysis and subsequent optimization of the production process. The goal was to achieve lower process operating costs and increase production capacity. The theoretical part deals with process management, lean manufacturing, methods that eliminate waste, and tools to manage the efficiency of the production process. The practical part deals with the analysis of the current state of the production process. Based on this analysis, a new solution for the production process was proposed, which increases its efficiency. Finally, it is possible to identify undesirable types of waste that affect the performance of the company

Upgrading of wheat/barley and miscanthus bio-oil over a sulphided catalyst

In recent years, the production of biofuels from non-food crops wastes and harvesting residues plays an important role in the improvement of the global environment and in the replacement of declining oil reserves1. Hydrogenation of lignocellulosic bio-oil is attracting much attention as a suitable way to produce petroleum-refinery compatible feedstock. Primarily, hydrogenation of bio-oil is carried out under severe reaction conditions in two-stage fixed-bed reactors, filled with a noble metal catalyst in the first zone and with a sulphided catalyst in the second zone2. This setup allows producing low-oxygen upgraded bio-oil, however, it is economically unviable and operationally complicated. Here, we present the results from 80 h long hydrogenation experiments of miscanthus and wheat/barley straw bio‑oils obtained by one-stage condensation (2-5 °C) or fractional condensation (75 °C) ablative fast pyrolysis (AFP). Bio-oils from fractional condensation, in contrast to those from one-stage condensation, were stable and did not separate into an aqueous and organic phase. In that case, operation with these bio-oils was much easier than with bio-oils from one-stage condensation. Upgrading of bio-oils was performed in a one-stage fixed bed reactor filled with a laboratory-made NiMo/Al2O3 catalyst under constant reaction conditions (340 °C, 4 MPa and WHSV 1 h-1), which we identified in our previous research as suitable reaction conditions. Hydrogenated products separated spontaneously into an aqueous phase, formed predominantly by water, and an organic phase. In this work, we used various analytical methods for the determination of physicochemical properties (density, viscosity, elemental analysis etc.) and chemical composition (CAN, Carbonyls by Faix, GC-MS for volatile compounds and hydrocarbons) of the organic products. In addition, we used FTIR in combination with the principle component analysis (PCA) to take a snapshot of the catalyst health and product quality. In all hydrogenated products, we have observed a drop in the quality with the increasing time-on-stream, which may be caused by catalyst deactivation and coke formation, as it shown in Figure 2. Nevertheless, the coke formation and reactor clogging, during the hydrogenation of miscanthus bio-oil, was so high that we were forced to stop the experiment after 36 hours. The observed decrease in Micro Conradson Carbon residues and CAN of the products from wheat/barley straw bio-oil indicated a significant improvement of the product stability. The laboratory-made NiMo/Al2O3 catalyst was suitable for the upgrading of straw bio-oil, from one-stage and from fractional condensation AFP, and can be further developed for the upgrading for other feedstocks. Please click Additional Files below to see the full abstract

Boosting the Ni-Catalyzed Hydrodeoxygenation (HDO) of Anisole Using Scrap Catalytic Converters

The large availability and renewable nature of lignin makes its upgrading to bioproducts of particular interest for sustainable development. The hydrodeoxygenation (HDO) of anisole specifically represents a model reaction for the conversion of lignin to biofuels through the removal of the aromatic carbon-oxygen bonds. To date, a range of Ni-based catalysts have been reported as highly active systems for the HDO of anisole. However, there has been a substantial lack of consideration given to the environmental characteristics of these catalytic systems, in contrast with the scope of the sustainable production of biofuels. Herein, Ni-based SiO2 catalysts are prepared by a solventless and highly efficient mechanochemistry approach, having a considerably lower environmental impact as compared to standard impregnation methods. Importantly, scrap catalytic converters (SCATs) are employed as co-catalysts, proving the possibility of enhancing the catalytic HDO of anisole, with a scarcely exploited waste material. The results demonstrate that the combined use of Ni/SiO2 as catalysts and Ni/SCATs as co-catalysts remarkably boosts the rate of the conversion of anisole up to more than 50% by achieving an almost complete conversion of anisole in only 40 min instead of at 200 °C and 4 MPa H2

Potassium-modified bifunctional MgAl-SBA-15 for aldol condensation of furfural and acetone

The aldol condensation of furfural and acetone followed by hydrodeoxygenation into bio-jet fuel range alkanes and bio-polyester diols has attracted intensive interest in recent years. Such sequential reactions require a careful tailoring of one or more catalysts consisting of metal and acid–base active sites that can efficiently promote the two step cascade aldol condensation and hydrodeoxygenation. Here, we have begun developing a prominent base catalyst for mild aldol condensation of furfural and acetone by synthesizing acid–base bifunctional MgAl-SBA-15 and further modifying it with potassium. The catalyst with the highest basic site loading of 0.27 mmol g−1 showed a furfural conversion of 83% and 99% total selectivity to products comprising 54% 4-(2-furyl)-4-hydroxy-butan-2-one (FAc-OH, a C8 alcohol intermediate) and 23% of each 4-(2-furyl)-3-buten-2-one (FAc) and 1,4-pentadiene-3-one,1,5-di-2-furanyl (F2Ac) (C8 and C13 aldol condensation products, respectively) after 3 hours of reaction, at 50 °C. Though a higher loading of potassium causes severe blockages of mesopores and inaccessible acid sites, the catalyst could still be regenerated by open-air calcination and be re-used for considerable cycles with fair catalytic performances. Overall, the present study can be the stepping stone for future investigations on further tuning of non-interfering active sites in SBA-15 to promote an efficient one-pot transformation of furfural and acetone via the two-step cascade aldol condensation and hydrodeoxygenation

Tailoring ZSM-5 Zeolites for the Fast Pyrolysis of Biomass to Aromatic Hydrocarbons

The production of aromatic hydrocarbons from cellulose by zeolite-catalyzed fast pyrolysis involves a complex reaction network sensitive to the zeolite structure, crystallinity, elemental composition, porosity, and acidity. The interplay of these parameters under the reaction conditions represents a major roadblock that has hampered significant improvement in catalyst design for over a decade. Here, we studied commercial and laboratory-synthesized ZSM-5 zeolites and combined data from 10 complementary characterization techniques in an attempt to identify parameters common to high-performance catalysts. Crystallinity and framework aluminum site accessibility were found to be critical to achieve high aromatic yields. These findings enabled us to synthesize a ZSM-5 catalyst with enhanced activity, which offers the highest aromatic hydrocarbon yield reported to date.This is the peer-reviewed version of the following article: Hoff, Thomas C., David W. Gardner, Rajeeva Thilakaratne, Kaige Wang, Thomas W. Hansen, Robert C. Brown, and Jean‐Philippe Tessonnier. "Tailoring ZSM‐5 Zeolites for the Fast Pyrolysis of Biomass to Aromatic Hydrocarbons." ChemSusChem 9, no. 12 (2016): 1473-1482., which has been published in final form at DOI: 10.1002/cssc.201600186. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.</p

Cocaine by-product detection with metal oxide semiconductor sensor arrays

A range of n-type and p-type metal oxide semiconductor gas sensors based on SnO2 and Cr2O3 materials have been modified with zeolites H-ZSM-5, Na-A and H–Y to create a gas sensor array able to successfully detect a cocaine by-product, methyl benzoate, which is commonly targeted by detection dogs. Exposure to vapours was carried out with eleven sensors. Upon data analysis, four of these that offered promising qualities for detection were subsequently selected to understand whether machine learning methods would enable successful and accurate classification of gases. The capability of discrimination of the four sensor array was assessed against nine different vapours of interest; methyl benzoate, ethane, ethanol, nitrogen dioxide, ammonia, acetone, propane, butane, and toluene. When using the polykernel function (C = 200) in the Weka software – and just five seconds into the gas injection – the model was 94.1% accurate in successfully classifying the data. Although further work is necessary to bring the sensors to a standard of detection that is competitive with that of dogs, these results are very encouraging because they show the potential of metal oxide semiconductor sensors to rapidly detect a cocaine by-product in an inexpensive way

Nanosized TiO2: a promising catalyst for the aldol condensation of furfural with acetone in biomass upgrading

Nanosized TiO2catalyst was successfully prepared by a simple green procedure and used in liquid phasealdol condensation of furfural with acetone, a key step in bio-fuel processing. In order to determinethe effect of calcination temperature on catalytic properties of TiO2, the as-prepared TiO2and calcinedTiO2(150–900◦C) were studied by XRD, BET, TPD-CO2/NH3, TGA/DTG and FTIR evaluation. The catalyticperformance of TiO2samples in aldol condensation of furfural with acetone was evaluated and comparedwith that of Mg–Al hydrotalcites and a BEA zeolite. These experiments showed that uncalcined TiO2possessed reasonable activity in aldol condensation of furfural to acetone and resulted in commonlyproduced condensation products. The observed catalytic behavior of TiO2could be competitive withthat reported for other inorganic solids. The calcination of TiO2resulted, however, in a decrease in itscatalytic activity due to extensive dehydration and surface dehydroxylation as well as due to changes oftextural properties resulting in a decrease in the amount of accessible active sites. Thanks to its advancedproperties, nanosized TiO2is a promising catalyst for aldol condensation of furfural with acetone andcould broaden possibilities for optimizing conditions for bio-fuel production

On the influence of Si:Al ratio and hierarchical porosity of FAU zeolites in solid acid catalysed esterification pretreatment of bio-oil

A family of faujasite (FAU) zeolites with different Si:Al ratio, and/or hierarchical porosity introduced via post-synthetic alkaline desilication treatment, have been evaluated as solid acid catalysts for esterification pretreatments of pyrolysis bio-oil components. Acetic acid esterification with aliphatic and aromatic alcohols including methanol, anisyl alcohol, benzyl alcohol, p-cresol and n-butanol was first selected as a model reaction to identify the optimum zeolite properties. Materials were fully characterised using N2 porosimetry, ICP, XRD, XPS, FT-IR, pyridine adsorption, NH3 TPD, In-situ ATR and inverse gas chromatography (IGC). IGC demonstrates that the surface polarity and hence hydrophobicity of FAU decreases with increased Si:Al ratio. Despite possessing a higher acid site loading and acetic acid adsorption capacity, high Al-content FAU possess weaker acidity than more siliceous catalysts. Esterification activity increases with acid strength and decreasing surface polarity following the order FAU30>FAU6>FAU2.6. The introduction of mesoporosity through synthesis of a hierarchical HFAU30 material further enhances esterification activity through improved acid site accessibility and hydrophobicity. Methanol was the most reactive alcohol for esterification, and evaluated with HFAU30 for the pretreatment of a real pyrolysis bio-oil, reducing the acid content by 76% under mild conditions