A study of the importance of secondary reactions in char formation and pyrolysis : a dissertation presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Process Engineering at Massey University, Manawatū, New Zealand

Anthropogenic climate change, caused primarily by excessive emissions of carbon dioxide, has led to a renewed interest in char, the solid product of pyrolysis. When applied to soil as biochar it can both sequester carbon and improve soil function. To make its manufacture environmentally friendly and economically viable it is important to maximise char yield, which can be done by promoting secondary reactions. This research shows that secondary reactions, which are enhanced by prolonged vapour-phase residence time and concentration, not only increase the char yield but are the source of the majority of the char formed. All four biomass constituents (extractives, cellulose, hemicellulose and lignin) undergo secondary reactions concurrent with primary reactions over the entire pyrolysis range ≈ 140 to 500 °C, which makes it practically impossible to separate them. Secondary char formation was confirmed to be exothermic which affects the overall heat of pyrolysis. Impregnating the feedstock with the elements K, Mg and P, which are plant macro-nutrients naturally present in biomass, resulted in the catalysis of secondary char formation. The results reveal that a first order reaction model does not describe pyrolysis accurately when char formation is enhanced by catalysis and secondary reactions. Secondary char can be enhanced by increasing the particle size but there is a limit due to increased cracking and fracturing of the pyrolysing solid. This limitation is overcome by pyrolysis in an enclosed vessel, termed autogenous pressure pyrolysis, which was discovered to cause significant changes in the volatile pyrolysis products; indicating the co-production of a high quality liquid. This process, however, negatively affects the char properties relevant for biochar like the surface area, similar to self-charring and co-carbonisation of condensed volatile pyrolysis products. To increase research capabilities a unique high temperature/ high pressure reactor (600 °C at 20 MPa) was designed to allow the detailed characterisation of all three pyrolysis product classes under extreme pyrolysis conditions. This was demonstrated to be invaluable for understanding the underlying pyrolysis mechanism and physical processes at play

Alternative fuels from Biomass and Power (PBtL) A case study on process options, technical potentials, fuel costs and ecological performance

Greenhouse gas emissions in the transport sector can significantly be reduced by replacing fossil based fuels with biomass-based alternatives. Several promising fuel production paths of the second generation made from residues and waste wood had already been developed in recent years. These fuel concepts typically suffer from the axiomatically limited technical potential of biomass resources in central Europe. Furthermore, fuel costs are currently not competitive on the market. In order to change this state, the German Aerospace Center has refined existing Biomass-to-Liquid (BtL) and Power-to-Liquid (PtL) concepts to the so-called Power&Biomass-to-Liquid concept. The main idea is to utilize the large technical exploitation potential of renewable electricity in modified BtL plants. The case study presents detailed results on promising process configurations of Fischer-Tropsch PBtL concepts based on different gasifier and electrolyzer technologies, the expectable technical fuel potential, fuel production costs and CO2 footprint. As a result, the fuel output of BtL plants can be nearly quadrupled at the same biomass input. Hence, fuel costs can significantly be reduced due to economy of scale effects. Furthermore, the specific CO2 footprint of the fuel is reduced as well

Preoperative Endoscopy and Its Impact on Perioperative Management in Bariatric Surgery

BACKGROUND The role of preoperative upper-gastrointestinal endoscopy for bariatric surgery is still understood only with controversy. The aim of this study was to evaluate the prevalence of endoscopic findings and its impact on perioperative management. METHODS Patients who underwent bariatric surgery at our center between 2010 and 2013 were systematically analyzed from a prospective database. RESULTS Two hundred and twelve patients with a median body mass index of 50 kg/m(2) (range 29-87) underwent 216 bariatric procedures at our center between 2010 and 2013. All patients received preoperative upper endoscopy. In 159 cases (75%), the endoscopy was performed at our center. These cases were included in this study. In 37 cases (23%), no abnormal findings were detected. In 122 cases (76%), upper endoscopy revealed pathologies. No further treatment was necessary in 24 cases (15%). Medical treatment was changed in 81 cases (51%). The operation was delayed due to medical treatment and re-endoscopy in 13 cases (8%). The surgical approach was changed in 4 cases (3%). CONCLUSION Routinely performed preoperative endoscopy before bariatric surgery revealed a high prevalence of gastrointestinal diseases with a significant impact on perioperative management in two thirds of the cases. Therefore, we recommend routine gastroscopy about 2-4 weeks prior to surgery

The Experimental Oxime K027—A Promising Protector From Organophosphate Pesticide Poisoning. A Review Comparing K027, K048, Pralidoxime, and Obidoxime

Poisoning with organophosphorus compounds (OPCs) is a major problem worldwide. Standard therapy with atropine and established oxime-type enzyme reactivators (pralidoxime, obidoxime) is unsatisfactory. In search of more efficacious broad-spectrum oximes, new bispyridinium (K-) oximes have been synthesized, with K027 being among the most promising. This review summarizes pharmacokinetic characteristics of K027, its toxicity and in vivo efficacy to protect from OPC toxicity and compares this oxime with another experimental bisquaternary asymmetric pyridinium aldoxime (K048) and two established oximes (pralidoxime, obidoxime). After intramuscular (i.m.) injection, K027 reaches maximum plasma concentration within ∼30 min; only ∼2% enter the brain. Its intrinsic cholinesterase inhibitory activity is low, making it relatively non-toxic. In vitro reactivation potency is high for ethyl-paraoxon-, methyl-paraoxon-, dichlorvos-, diisopropylfluorophosphate (DFP)- and tabun-inhibited cholinesterase. When administered in vivo after exposure to the same OPCs, K027 is comparable or more efficacious than pralidoxime and obidoxime. When given as a pretreatment before exposure to ethyl-paraoxon, methyl-paraoxon, DFP, or azinphos-methyl, it is superior to the Food and Drug Administration-approved compound pyridostigmine and comparable to physostigmine, which because of its entry into the brain may cause unwanted behavioral effects. Because of its low toxicity, K027 can be given in high dosages, making it a very efficacious oxime not only for postexposure treatment but also for prophylactic administration, especially when brain penetration is undesirable

Conception of an Eddy Current In-process Quality Control for the Production of Carbon Fibre Reinforced Components in the RTM Process Chain

The integration of quality control processes in immature production systems such as the resin transfer moulding (RTM) process in the production of carbon fibre reinforced plastics (CFRP) faces numerous challenges. Requirements towards the reliability and product design as well as the consideration of economic restrictions lead to challenging requirements for measurement systems. This paper presents the development of a process integrated quality control using eddy current inspection. The concept focuses on an eddy current sensor array that is integrated in a preforming tool and thus enables a 100% quality control of CRFP parts with minor effects on the production environment

Methylene Blue Inhibits Cromakalim-Activated K\u3csup\u3e+\u3c/sup\u3e Currents in Follicle-Enclosed Oocytes

The effects of methylene blue (MB) on cromakalim-induced K+ currents were investigated in follicle-enclosed Xenopus oocytes. In concentrations ranging from 3–300 μM, MB inhibited K+ currents (IC50: 22.4 μM) activated by cromakalim, which activates KATP channels. MB inhibited cromakalim-activated K+ currents in a noncompetitive and voltage-independent manner. The respective EC50 and slope values for cromakalim-activation of K+ currents were 194 ± 21 µM and 0.91 for controls, and 206 ± 24 µM and 0.87 in the presence of 30 μM MB. The inhibition of cromakalim-induced K+ currents by MB was not altered by pretreatment with the Ca2+ chelator BAPTA, which suggests that MB does not influence Ca2+-activated second messenger pathways. K+ currents mediated through a C-terminally deleted form of Kir6.2 (KirΔC26), which does not contain the sulfonylurea receptor, were still inhibited by MB, indicating direct interaction of MB with the channel-forming Kir6.2 subunit. The binding characteristics of the KATP ligand [3H]glibenclamide are not altered by MB in a concentration range between 1 μM-1 mM, as suggested by radioligand binding assay. The presence of a membrane permeable cGMP analogue (8-Br-cGMP, 100 µM) and a guanylate cyclase activator (BAY 58-2667, 3 µM) did not affect the inhibitory effects of MB, suggesting that MB does not inhibit cromakalim-activated K+ currents through guanylate cyclase. Collectively, these results suggest that MB directly inhibits cromakalim-activated K+ currents in follicular cells of Xenopus oocytes

Kosten und Potenziale von alternativen Kraftstoffen auf der Basis von Biomasse und erneuerbarem Strom – Eine Fallstudie

Die deutschen und europäischen Ziele zur CO2-Reduktion im Verkehrssektor erfordern den Einsatz von alternativen Kraftstoffen in der Luftfahrt und dem Schwerlastverkehr. Diese alternativen Kraftstoffe müssen vorzugsweise aus erneuerbaren Rohstoffen und Energiequellen zu möglichst wettbewerbsfähigen Kosten hergestellt werden. In diesem Artikel werden einige vielversprechende Prozessvarianten für alternative Kraftstoffe, die Herstellung von Fischer- Tropsch-Kraftstoff aus Biomasse, Strom und CO2, techno-ökonomisch bewertet. Dazu wurde jeweils ein Biomass-to-Liquid (BtL)- Power-to-Liquid (PtL)- and Power & Biomass- to-Liquid (PBtL)-Konzept in Prozesssimulationssoftware abgebildet, energetisch optimiert und ökonomisch untersucht. Der Vergleich der Herstellungsoption alternativer Kraftstoffe zeigt, dass die Sektorkopplung zwischen Strom- und Kraftstoffmarkt erforderlich ist, um die gesetzten politischen Ziele bis 2020 zu erreichen. Die Ergebnisse der Fallstudie zeigen, dass bei gleichem Biomasseeinsatz die Kraftstoffausbeute im PBtL-Konzepte um den Faktor 3 bis 4 erhöht wird. Dadurch kann das vorhandene nutzbare Biomassepotenzial effizienter eingesetzt werden. Die Kraftstoffherstellungskosten hängen zu einem hohen Grad von den ökonomischen Randbedingungen und der Anlagengröße ab. PtL-Anlagen habenKostenvorteile bei niedrigem Strompreis und kleinen Anlagen, während PBtL-Anlagen aufgrund der Bedeutung von Skaleneffekten bei großen Anlagenkapazitäten zu den geringsten Herstellungskosten führen. Jedoch ist davon auszugehen, dass die Herstellungskosten alternativer Kraftstoffe unter Berücksichtigung des derzeitigen Ölpreises ohne politische Förderung nicht wettbewerbsfähig sein werden