Ammonia cycle

The condensate polishing system must be in excellent working order and typically operating in the ammonia cycle. 

The global nitrogen cycle is often referred to as the nitrogen cycles, since we can view the overall process as the result of the interactions of various biological and abiotic processes. Each of these processes, to a first approximation, can be considered as a self-contained cycle. We have already considered the biological cycle from this perspective (Fig. 12-1), and now we will look at the other processes, the ammonia cycle, the cycle, and the fixation/denitrification cycle. 

The main advantage of this form of unit is the very great reduction in the volume of gas handled by the compressor. Thus, 1 kg of water vapour at, say, 311 K, with a volume of 22 m3 and latent heat about 2560 kJ/kg, passes this heat to ammonia at a temperature of say 305 K. About 2.1 kg of ammonia will be vaporised to give a vapour with a volume of only about 0.22 m3 at the high pressure used in the ammonia cycle. 

DENMEAD, O.T., FRENEY, J.R. and SIMPSON, J.R. (1976). A closed ammonia cycle within a plant canopy. Soil Biology and Biochemistry, 8, 161-164. 

Dentener FI, Crutzen PJ. 1994. A three-dimensional model of the global ammonia cycle. Journal of Atmospheric Chemistry 19 331-369. 

The answers are combined cycle—power input =—13.28 kW, power output = 988.0 kW, net power output = 974.7 kW, rate of heat added = 2994kW, rate of heat removed = —2019kW, and j = 32.56% topping steam cycle—power input = —2.02kW, power output = 898.5 kW, net power output = 896.5 kW, rate of heat added = 2994 kW, rate of heat removed = —2098 kW, and = 29.94% bottom ammonia cycle—power input= — 11.26kW, power output = 89.53 kW, net power output = 78.27 kW, rate of heat added = 2098 kW, rate of heat removed = — 2019kW, t] = 3J3%, and mass rate flow = 1.75kg/sec. (See Fig. 5.4.)... 

OCEAN THERMAL ENERGY CONVERSION (OTEC). Utilization of ocean temperature differentials between solar-heated surface water and cold deep water as a source of electric power. In tropical areas such differences amount to 35-40°F. A pilot installation now operating near Hawaii utilizes a closed ammonia cycle as a working fluid, highly efficient titanium heat exchangers, and a polyethylene pipe 2000 feet long and 22 inches inside diameter to handle the huge volume of cold water required. Alternate uses for such a system, such as electrolysis of water,... 

The first human experiments which suggested a toxic effect of ammonia in disease were done by Van Caulaert. The revival and extension of this work by the group led by Davidson (G2) in the Boston City Hospital has stimulated widespread interest in ammonia as a factor in the production of mental symptoms in liver disease. The ability of various factors, such as urea feedings, high-protein diet, cation resins in the ammonia cycle, and amino acids, to induce symptoms of coma in patients with liver disease (G2, M3, M4, P7, S8) made it quite clear that ammonia was associated with the symptom complex called hepatic coma. The severe toxicity of ammonia in animals and the ability of intravenous or oral ammonium salts to provoke episodes of impending liver coma tended to substantiate the clinical impressions. Rapid confirmation of these observations was furnished by the experiments of other groups (Bll, C2, E2, FI). 

The sulfur—ammonia cycle appears to be a previously unexplored cycle that has been put forward by the Florida Energy Centre in the USA. The novel step in the process is the photocatalytic oxidation of ammonium sulfite, (NH4)2S03, to ammonium sulfate, (NH4)2S04. The latter is then used to split water. 

However, a standard 18-8 CrNi steel shows only a very shallow nitriding depth, and experience has proven that this steel can be used for years in the ammonia cycle gas at 450°C. After 10 years, the penetration depth of nitration is 1 mm at most. 

Ammonia-compressor refrigeration machine (Carl von Unde) Breweries need refrigeration so they can brew year-round. Linde refines his ammonia-cycle refrigerator to make this possible. 

Dentener, F.J. Cmtzen, P.J., 1994 A Three Dimensional Model of the Global Ammonia Cycle , in Journal of Atmospheric Chemistry, 19 331-369. 

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