German hardness

FIG. 36 Synergistic mixture of alkane- (paraffin) sulfonates (PS) and fatty alcohol ether sulfates (FAES). Cleaning effect in miniplate test at 50°C, tap water (12° German hardness), 0.075 g of active surfactant mixture per liter. 

The reactants, coal, water and oxygen are converted to hydrogen, carbon monoxide, carbon dioxide, methane, water vapour and hydrogen sulphide at a given temperature and pressure according to thermodynamic equilibria and the kinetics of gasification. A particular coal composition which is characteristic of a German hard coal was taken as a basis (Table I). 

Specks, R., Klusmann, A. German hard coal conversion projects Energy Prog., 2,60 (1982) Stadelhofer, J. W., Gerhards, R. C n.m.r. study on hydroaromatic compounds in anthracene oil Fuel, 60, 367 (1981)... 

In normal soft water the corrosion of zinc and zinc alloys is dependent on the oxygen content, which is generally 6-10 mg/L. Hard waters usually produce a protective film, but for water of 2°-6° German hardness, chloride should not exceed 75 mg/L and for water exceeding 6°C German hardness, it should not exceed 150 mg/L if the protective film is to remain sulfate, however, can be substantially higher. Ammonium salts are always unfavorable and should never exceed 20 mg/L. Copper is especially harmful and should be as low as possible, substantially under 0.1 mg/L. At 2 temporary hardness, zinc is attacked below pH 6.8, but in harder water of 2-6 and 7.6-9.6 pH there is no attack if at least 5 mg/L oxygen is present. 

The water is conditioned by pellet softening in up-flow fluidized bed reactors Scheveningen uses Ca(OH)2 solution, whereas Monster uses NaOH solution. The hardness of the water recovered from the dunes has been reduced from 2.3 to 1.6 mmol/1 (from 13 to 8.5 German hardness degrees and the pH has been raised from about 7.8 to about 8.5. 

Aqueous dilutions in water of 20° German hardness were used in the tests. From the suppliers data sheets, the boron-containing compounds can be characterised as follows ... 

Remark 1°dH (degree German Hardness) corresponds with 0,18 mmol T alkaline-earth metal ions... 

W. Brunke, R. Durrfeld, J. Langhoff, and J. Hebbel. "Production of Synthesis Gas from German Hard Coal by the Texaco Gasification Process." Presented at the Seventh EPRI Coal Gasification Contractors Conference, Palo Alto, California, October 1987. 

The dawn of the nineteenth century saw a drastic shift from the dominance of French chemistry to first English-, and, later, German-influenced chemistry. Lavoisier s dualistic views of chemical composition and his explanation of combustion and acidity were landmarks but hardly made chemistry an exact science. Chemistry remained in the nineteenth century basically qualitative in its nature. Despite the Newtonian dream of quantifying the forces of attraction between chemical substances and compiling a table of chemical affinity, no quantitative generalization emerged. It was Dalton s chemical atomic theory and the laws of chemical combination explained by it that made chemistry an exact science. 

Sodium—lead alloys that contain other metals, eg, the alkaline-earth metals, are hard even at high temperatures, and are thus suitable as beating metals. Tempered lead, for example, is a beating alloy that contains 1.3 wt % sodium, 0.12 wt % antimony, 0.08 wt % tin, and the remainder lead. The German BahnmetaH, which was used ia axle beatings on railroad engines and cars, contains 0.6 wt % sodium, 0.04 wt % lithium, 0.6 wt % calcium, and the remainder lead, and has a Brinell hardness of 34 (see Bearing MATERIALS). 

Reliance on forcing consumers to subsidize is hardly unique to German coal. U.S. public utility regulation long has required unequal pricing among consumers. Historically, emphasis was on rates that caused industrial and commercial users to subsidize residential users. This has encouraged industrial customers to secure rate reforms. These are equity measures that are subject to the criticisms stated above. 

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