Autothermal two-stage gasification of low-density waste-derived fuels

In order to increase the efficiency of waste utilization in thermal conversion processes, pre-treatment is advantageous. With the Herhof Stabilat^® process, residual domestic waste is upgraded to waste-derived fuel by means of biological drying and mechanical separation of inerts and metals. The dried and homogenized waste-derived Stabilat^® fuel has a relatively high calorific value and contains high volatile matter which makes it suitable for gasification. As a result of extensive mechanical treatment, the Stabilat^® produced is of a fluffy appearance with a low density. A two-stage gasifier, based on a parallel-arranged bubbling fluidized bed and a fixed bed reactor, has been developed to convert Stabilat^® into hydrogen-rich product gas. This paper focuses on the design and construction of the configured laboratory-scale gasifier and experience with its operation. The processing of low-density fluffy waste-derived fuel using small-scale equipment demands special technical solutions for the core components as well as for the peripheral equipment. These are discussed here. The operating results of Stabilat^® gasification are also presented.     

Near-wall porosity characteristics of fixed beds packed with wood chips

Packed beds of fuel wood chips are commonly found in thermal conversion processes such as combustion or gasification. Wood chips in particular are mostly used as fuel for small-scale domestic heating boilers but also for commercial-scale combustion units. The characterization of spatial voidage distribution inside the wood chip beds is of great importance for flow and reactor modelling. This study focuses on the radial porosity variations of cylindrical beds of three different types of commercially available wood chips including chips classified as G30 size class. The conventional technique of consolidating packed beds with a resin was chosen as the experimental procedure. The radial voidage distribution in different cylindrical beds is determined by image analysis of sections of the solidified packings. Additionally, a packing of monosized spheres was investigated in order to assess the selected procedure in comparison with widely available literature data for spheres. The results are discussed and summarized in a mathematical expression correlating the radial voidage distribution depending on average wood chip size, packing core porosity and dimensionless distance from the tube wall.     

Evaluation on a two-day time scale of high-reliability electronic assemblies by in-situ electrical and opto-mechanical test techniques

We present the results of SHORTEST, a BRITE EURAM II project for the introduction in industry of an advanced approach to the reliability evaluation of electronic assemblies. The achievements so far are the development and validation of seven in-situ test techniques. Five of the test techniques demonstrate the capability of detecting failure mechanisms at 48 hours with moderate stress conditions, and half of the in-situ test results obtained at 48 hours on 10 subtechnologies correlate with conventional tests. All correlation results are presented. The application of the method for quality assurance and building-in reliability is discussed. The final aim of SHORTEST is to look for the exploitation of the developed in-situ techniques. The marketing study that will define the industrial needs of European companies is presented. In parallel, the insertion in the CECC specification of recommendations based on the SHORTEST principle is foreseen.     

Marijuana as a medicine

Determination of level of CA 19-9 cancer-embryonal antigen (CEA) and alpha-fetoprotein (AFP) is an objective test in the diagnosis of gastric, pancreatic and colonic cancer and may be applied for prognosis and estimation of the treatment efficacy.     

Simple method of measuring drift-mobility profiles in thin semiconductor films

A simple method of measuring drift-mobility profiles in semiconductor films is described. It is based on the low-frequency measurement of the transconductance and gate capacitance of an f.e.t. structure as a function of gate bias. Drift mobilities of 4000 to 5000 cm2/Vs have been measured on n-type GaAs films with 1016 to 1017 cm?3 doping levels.     

Thermisches Betriebsverhalten einer Bandsinteranlage

Es wird ein vereinfachtes mathematisches Modell vorgestellt, mit dessen Hilfe das thermische Betriebsverhalten einer Bandsinteranlage in Abhängigkeit verschiedener Parameter wie Koksgrusgehalt oder Feuchte der Sintermischung beschrieben werden kann. Das Modell enthält als Grundgleichung die instationäre Wärmetransportgleichung, die mit einem modifizierten Newton-Euler-Verfahren gelöst wird. Es ist so konzipiert, daß es in ein umfassendes Energiemodell für ein Hüttenwerk integriert werden kann. Es dient damit im weiteren Sinne als Hilfsmittel für die Energiesteuerung im Hüttenwerk. Durch Simulationsrechnungen wird der Einfluß von Wärm- und Wärmebehandlungshauben über dem Sinterband auf die Leistungsfähigkeit der Sinteranlage aufgezeigt. Je nach Abdeckungsgrad des Sinterbandes durch Wärmhauben und den dort herrschenden Temperaturen kann bis zu 15% Koksgrus eingespart werden.     

Ascorbic acid reduces the endotoxin-induced lung injury in awake sheep

Our aim was to investigate whether ascorbic acid can reduce reactive oxygen metabolite-mediated acute lung injury. The effects of intravenous administration of Escherichia coli endotoxin were studied, with and without ascorbic acid infusion, on haemodynamics, lung lymph flow, cardio-respiratory and neutrophil function in chronically instrumented sheep. Paired experiments were performed on eight sheep in which they received either endotoxin alone (0.5 micrograms kg-1 b.w.) (ET group) or in combination with an ascorbic acid infusion (1 g kg-1 b.w. bolus injection followed by 0.2 g kg-1 h-1 continuous infusion) ET + ASC group) in random order. Four of the animals also received ascorbic acid alone (ASC group). As a result, for the ET + ASC group a general and mostly significant improvement (P < 0.05) in the early hypertensive phase (0-60 min, P values) and in the late permeability phase (2-4 h, *P values) of cardiorespiratory function (mean artery pressure: P/*P = 0.283/0.049; mean pulmonary artery pressure: P/*P = 0.0001/0.0001; mean pulmonary artery wedge pressure: P/*P = 0.012/0.001; right ventricular stroke work index: P/*P = 0.02/0.0001; cardiac index: P/*P = 0.797/0.755; arterial oxygen saturation: P/*P = 0.0059/0.01; arterial-venous difference of oxygen tension: P/*P = 0.011/0.0005), oxygen consumption: P/*P = 0.013/0.035, lung lymph flow: P/*P = 0.562/0.012, lymph/plasma protein ratio: P/*P = 0.304/0.008 and protein clearance: P/*P = 0.56/0.05 was observed in comparison with the ET group.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hydrogen energy from coupled waste gasification and cement production—a thermochemical concept study

A plant concept for hydrogen production from waste gasification coupled with cement manufacturing is presented. Hot precalcined cement meal, from the operating cement process, is used as heat carrier to provide energy required by the parallel arranged gasifier. The amount of CaO present in the cement meal operates simultaneously as an effective in situ _CO2${\mathrm{CO}}_2$-sorbent. First, a practical case study was devised to be able to perform simulations for estimation of expected hydrogen yield. The influence of different operation parameters of the gasifier and the hydrogen separation unit (steam-to-fuel ratio, pyrolysis temperature, PSA efficiency) was studied based on chemical equilibrium calculations. The simulation results indicate, that the coupling provides advantages for both processes. The production of a hydrogen-rich gas via thermal gasification benefits from the continuously available fresh CaO, which improves fuel conversion reactions and captures _CO2${\mathrm{CO}}_2$ in situ. High-calorific streams from gasification process remaining after hydrogen separation may substitute fossil fuels needed for cement process. For a steam/fuel ratio of 0.3 and a PSA efficiency of 0.7, the calculated hydrogen energy yield is 46% of fuel energy input.