Performance and Problems of Claus Plant Operation on Coke Oven Acid Gases

The application of Claus Plant sulfur recovery units to the coke oven gas (COG) acid gases at three Bethlehem Steel Corporation plants is discussed. While many of the problems encountered are not unique to coke oven gas-derived acid gases, it was found that special consideration must be given to the effect of components not normally encountered in the typical Claus plant application to petroleum derived gases. It is perhaps fortunate that the feed composition to the three units was sufficiently different to expedite recognition of the source of some of these difficulties. One substance of concern is the hydrogen cyanide normally found in COG acid gases. In the absence of some means of removing or decomposing this material before it enters the Claus Plant extensive corrosion within the unit is observed after a short period of time. This is due to the fact that, contrary to expectation, a substantial quantity of this material survives the burner flame. The various alternatives in its elimination are discussed. A second major contaminant in COG acid gases is particulate iron sulfide and iron cyanide. While the exact source of these materials is in doubt, there is little doubt that in the absence of their removal, inorganic blockages within the Claus Plant will occur. By properly accounting for the special properties of coke oven gas-derived acid gas we have recently achieved short term sulfur recovery efficiencies of 95% and higher.     

Multivariate Patterns of Antioxidative and Photoprotective Defence Compounds in Spruce Needles at Two Central European Forest Sites of Different Elevation

In this work we measured a set of antioxidative and photoprotective compounds (chlorophylls, carotenoids, tocopherol, ascorbate and glutathione), which were suggested previously as stress markers in conifer needles, at two spruce forest sites at different elevation in Saxony, Germany. Most variables differed significantly between current and 1-year-old needles, but only the content of the xanthophyll cycle per mg total chlorophyll and the oxidation state of glutathione were significantly different between the sites. We applied principal component analysis (PCA) to address the question if underlying accumulated variables are similar to the ones found in spruce needles across Alpine elevation profiles and/or for pines in Mediterranean ecosystems. Four principal components (accumulated variables, PC) representing 68% of the total variance of the dataset were extracted. PC 1 encompassed total chlorophyll, lutein, and β-carotene contents, PC 2 combined the epoxidation state of xanthophylls, ascorbate content and redox state, and glutathione content, PC 3 represented the content of xanthophylls and the redox state of glutathione, and PC 4 encompassed the content of α-carotene and the epoxidation state of xanthophylls. Only PC 3 was significantly different between sites. The PCA structure shows many similarities to corresponding findings in studies on spruce in mountain forests in the Alps and pines in Mediterranean systems. This corroborates the interpretation of PCs as indicative for underlying physiological processes. However, separation of the two investigated sites by PCs was in the present case study not superior to the separation by single input variables.     

Climate change and institutional change: what is the relative importance for economic performance?

Environmental Economics and Policy Studies - A growing empirical literature attempts to assess the effect of climate and institutional quality (measured by e.g. economic freedom) on economic...     

Long-term effects of short-term perturbation in a subalpine grassland

Theoretical advances and short-term experimental studies have furthered our understanding of how ecosystems respond to perturbation. However, there are few well-replicated experimental studies that allow an assessment of long-term responses. Results from a controlled, large-scale field experiment in a subalpine grassland near Interlaken, Switzerland, show that 2-4 years of liming (Ca: 40 g x m(-2) x yr(-1)) still significantly affected the composition of the vegetation and the soil microbial community nearly 70 years after the treatments were imposed, whereas NPK fertilization (8 g x m(-2) x yr(-1)) only marginally affected vegetation composition. The exchangeable content of Ca ions and soil pH were higher in limed plots but were unaffected in fertilized plots. Plant species and PLFAs (phospholipid fatty acids) indicating low pH values were found in higher abundance in the unlimed plots, suggesting that the long-lasting effects of liming on the above- and belowground communities were mediated through changes in soil pH. The results of this long-term study indicate that the resilience of mountain ecosystems may be particularly low in response to perturbations that substantially alter soil pH or other key determinants of belowground processes.     

Image as investigation: sciences of the otherworldly at the Bauhaus

While modern architecture and design have often been seen as harsh and impersonal, this essay reassesses this association through a closer look at the influence of mysticism and the occult on the Bauhaus, an interwar German reform movement and school for art, craft, design, and architecture. Even as they developed their famous streamlined designs, members of the school also produced images based on alternative religions, spiritism, and other experimental and occult practices. Such images participated in a broader context of research into the otherworldly and a rediscovery of nature and the environment. Reintegrating this other history into what we know of the Bauhaus allows us to understand modernism anew, not as cold and soulless but as part of larger attempts to perceive and shape a new world that was quickly unfolding around its subjects.     

Real-world vehicle emissions as measured by in situ analysis of exhaust plumes

Environmental Science and Pollution Research - We conducted a 60-day roadside measurement campaign on a busy street in Münster, Germany, during summer 2016. We used gas and particle...     

Climate change impacts in Central Asia and their implications for development

Regional Environmental Change - This paper synthesizes what is known about the physical and biophysical impacts of climate change and their consequences for societies and development under...     

Mechanistic aspects of the thermal formation of halogenated organic compounds including polychlorinated dibenzo‐p‐dioxins. Part IV†: Incorporation of inorganic chlorine into organic matter and thermochemical aromatizations

The pyrolysis and chlorination of petroleum coke in a NaCl‐KCl melt results in the production of CCl₄ and C₆Cl₆. Polychlorinated dibenzo‐p‐dioxins (PCDDs) are produced from the air oxidation and chlorination of coal using HCl or Cl₂. Smoking of tobacco containing ³⁶Cl^e provides CH₃ ³⁶Cl.

At 350°C, the rateof aromatization of 1,3‐cyclohexadiene is negligible as compared to that of 1,4‐cyclohexadiene. The aromatization of the latter diene proceeds through the molecular elimination of hydrogen; while that of 1,3‐cyclohexadiene expecially at higher pressure (10–90 Torr) and at 362–421 °C involves free radical chain mechanism.     

Fatty acids in fish scales

This study represents the first determination of lipids and fatty acids in fish scales. Scales collected from groups of Atlantic salmon reared on fish farms and in experimental tanks were analyzed by chromatography. The complete suite of fatty acids normally found in marine organisms was detected in the scales, with the following fatty acids dominating: 16:0, 18:0, 18:1n9, 20:5n3, 22:6n3 and 24:1n9. Scales contained relatively high levels of furan fatty acids, and the level of cholesterol (2.5–5 mg/g tissue) was much higher than the levels found in the edible parts of marine fishes (0.2–1 mg/g tissue). The fatty acid profile of scales was distinct between groups of salmon originating from different commercial strains reared on the same farm, between salmon groups originating from the same strains but reared at different farms, and between groups of fed and unfed salmon in experimental tanks. Together, these data indicate that the fatty acid composition of fish scales is dependent upon both environmental and genetic factors. The fatty acid composition of fish scales may be used in stock/population identification, for example identification of escaped Atlantic salmon to farm of origin.