الفهرس 
Title : Operating cost reduction of an ammonia plant using a simulation model of an absorption refrigeration cycle
SummaryOnly 14 pages are availabe for public view
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Abstract
The high usage of utility streams increases the operating cost of a running ammonia plant located in Egypt. Thus, decreasing the consumption of these streams will lower the operating expenses and increase the profit of the plant.
The final cooler of process gas compression unit consumes large quantity of cooling water to absorb high amount of low-grade heat and cool down the process gas before introducing it to ammonia synthesis loop.
In the present thesis, process gas compression unit was simulated using Aspen HYSYS V8.8 then the results of inter-stage coolers of the simulation model were compared with the actual data of the plant.
The large amount of low-grade heat in the final cooler was recovered and used as a source of heat in an ammonia-water absorption refrigeration cycle as absorption refrigeration cycles shows their ability in restoring this type of heat.
Aspen HYSYS V8.8 was used to build a steady state simulation model for the proposed absorption refrigeration cycle and identify its operating conditions.
The proposed absorption refrigeration cycle saves 374,332 kg/h of cooling water and 3500 kg/h of low-pressure steam which is used in raising the temperature of feed natural gas to the required value.
The cost evaluation study showed that the proposed absorption refrigeration cycle decreases the operating cost by 529,385.34 $/year, the net present value of this investment is 965,588.1 $ and the return on investment is 39.1%. so, the proposed absorption refrigeration cycle is economically recommended.