System analysis of the secondary condensation unit in the context of improving energy efficiency of ammonia production

Algorithmic tools for optimizing the temperature regime of evaporator at absorption-refrigeration units of ammonia production

“…It should be noted that constraints in the research are predetermined by the range of change in the coordinates in the process of constructing a mathematical model of the evaporator. In this case, based on the results of building a new energy-efficient hardware-technological implementation of the unit for secondary condensation, the magnitude of temperature 1CG Θ is a constant at the level of 9.2 °C at the maximum thermal load for CG at the inlet [4]. Fig.…”

“…According to the available studies, a rise in the atmospheric air temperature from −6 °C to 30 °C, despite the growth in the ARU cooling capacity from 2.44 MW to 3.25 MW, causes an increase in the temperature of cooling of CG from −8 °C to 4 °C [3]. However, raising this temperature even by 1 °C leads to a decrease in the energy efficiency of the unit for synthesis in general at the expense of the increased annual consumption of natural gas to an additional steam boiler by 307.3 thousand nm 3 in order to obtain water vapor of high pressure, which ensures the drive of a centrifugal three-body compressor for CG compression and a fresh nitrogen-hydrogen mixture at the synthesis unit [4]. Thus, minimizing the temperature mode of CG cooling at ARU evaporators through the creation of an automated system of optimal software control acquires special relevance for the overall process of improving the energy efficiency of large tonnage units for ammonia synthesis.…”

Identification of heat exchange process in the evaporators of absorption refrigerating units under conditions of uncertainty

“…According to available studies, an increase in this temperature even by 1 °C decreases energy efficiency of the synthesis aggregate due to an increase in the consumption of natural gas by the additional steam boiler by 307.3 thousand nm 3 per year. This steam boiler enables obtaining high pressure water vapor (10.5 MPa), which is used to drive a centrifugal compressor of nitrogen-hydrogen mixture (NHM) and CG compression [4]. That is why minimization of the CG cooling temperature mode in evaporators of ARU through creation of high-quality automated adaptive system of optimal control becomes especially relevant for improving energy efficiency of ammonia production.…”

“…In this case, temperature of CG and ammonia concentration in CG at the unit's inlet varies respectively in the ranges of 35÷45 °C and 9÷12 % by volume, and therefore at the ARU evaporator inlets. It was found in the previous research into condensation columns that an increase in this concentration affects not only an increase in heat load, but also an increase in heat transfer coefficient due to formation of additional condensation thermal resistance [4]. In this case, uncertainty of the latter can be numerically evaluated by statistical methods when there is information about the magnitude of voluminous ammonia concentration in CG at the evaporator inlets at certain moments of time 3 NH a .…”

Formation of the information array of the identifier of the adaptive control system of the ammonia production condensation unit with uncertainties

“…Підвищення ж цієї температури навіть на 1°С призводить до зниження енргоефективності виробництва внаслідок збільшення річних витрат природного газу у додатковий паровий котел на 307,3 тис. нм 3 [1]. Тому мінімізація температурного режиму охолодження ЦГ у блоці вторинної конденсації за рахунок створення комп'ютерноінтегрованих технологій управління становить актуальну проблему у загальному процесі підвищення енергоефективності виробництва аміаку.…”