PERFORMANCE MODELLING AND SIMULATED AVAILABILITY OF SHELL GASIFICATION AND CARBON RECOVERY UNIT OF UREA PLANT

摘要

The present paper deals with the performance modelling and simulated availability of shell gasification and carbon recovery unit of urea plant. The fertilizer plant comprises of various units viz. shell gasification and carbon recovery, desulphurisation, co-shift conversion, decarbonation, nitrogen wash and ammonia synthesis etc. One of the most important functionaries of a urea plant is shell gasification and carbon recovery unit. This unit consists of four subsystems arranged in series and parallel configurations. The performance modelling has been developed with the help of mathematical formulation based on Markov Birth-Death process using probabilistic approach. For this purpose, first differential equations have been developed. Then these equations are further solved by using normalizing conditions so as to determine the steady state availability i.e. measure of performance of shell gasification and carbon recovery unit. This performance evaluating system deals with the quantitative analysis of all factors (courses of actions and states of nature), which influence all maintenance decisions associated with the shell gasification and carbon recovery unit. The results of this paper are therefore, considered to be useful for the performance evaluation and determination of the best possible maintenance strategies in a urea plant concerned.