Urea production from waste gases

Onesnaževanje okolja z odpadki in odpadnimi plini postaja vse večji problem. K zmanjševanju onesnaževanja lahko pripomoremo s ponovno uporabo odpadkov in odpadnih plinov, s čimer zmanjšamo količino nakopičenih smeti in izboljšamo kakovost zraka. Sečnino industrijsko proizvajamo iz amonijaka in ogljikovega dioksida, pri čemer slednjega lahko pridobimo iz odpadnih plinov, ki nastajajo pri gorenju fosilnih goriv v termoelektrarnah. S pridobivanjem surovin iz odpadnih plinov preprečujemo nadaljnje onesnaženje okolja in zmanjšamo porabo osnovnih surovin. Namen diplomske naloge je izdelati simulacijo proizvodnje sečnine iz odpadnega plina ter določiti optimalno temperaturo in tlak. Simulacije proizvodnega procesa so narejene z računalniškim programom Aspen Plus. Rezultati kažejo, da s povišanjem tlaka in znižanjem temperature povišamo presnovo v reaktorju. Optimalni pogoji poleg presnove izboljšajo proces tudi z ekonomskega vidika, saj z manjšimi stroški in ob manjši količini vhodnih surovin proizvedemo več sečnine.Refuse and waste gas pollution have become two critical environmental issues. Reusing waste gases and other waste may help not only the environment by having lowered the amount of refuse accumulated, but also improve air quality. Urea can be manufactured from ammonia and carbon dioxide, the latter being produced from waste gases, a product of burning fossil fuels in thermal power stations. Raw material extraction based on waste gases allows a further decrease in pollution levels as well as saves primary resources. The aim of this paper is to create a simulation of waste-gas-based urea production and set the ideal pressure and temperature levels. All simulations are done in Aspen Plus. The results show that increasing the pressure and lowering the temperature would enhance urea production rates that take place in a reactor. Such improvements are pivotal for further economic optimisation of urea production in terms of lowering expenditure and raw material input