Design and simulation of natural gas purification process control

Pri proizvodnji prirodnog plina potrebno je provesti čišćenje od kiselih plinova kako bi se zadovoljile važeće norme. Separacija kiselih plinova provodi se postupkom apsorpcije pomoću otopine monoetanolamina. Za djelotvornu separaciju potrebno je projektirati postrojenje koje postiže potrebnu čistoću prirodnog plina pri različitim protocima i sastavima pojne smjese. Postrojenje je projektirano razvojem modela za stacionarno stanje u programskom paketu CHEMCAD. Da bi se ispitalo kako promjena protoka i sastava pojne smjese utječu na proces pročišćavanja provela se dinamička simulacija. Sustav za vođenje procesa projektirao se unutar dinamičkog načina rada CHEMCAD-a pri čemu se ispitivalo dinamičko vladanje procesa na promjene protoka i sastava pojne smjese. Simulacijsko istraživanje obuhvatilo je 10 regulacijska kruga koji reguliraju ključne varijable i održavaju stabilnost procesa. Pratio se odziv procesa na promjenu protoka i sastava pojne smjese, a analizirale su se vođene veličine i čistoća proizvoda. Na temelju rezultata istraživanja donio se zaključak o stabilnosti rada procesa u uvjetima promjene sastava i količine pojne smjese, kao i mogućnosti održavanja zahtjevane čistoće produkta unatoč dinamičkim promjena u procesu.In the production of natural gas is necessary to remove acid gases to meet the applicable standards. Acid gas is separated with absorption using a solution of monoethanolamine as absorbent. For effective separation it is necessary to design a plant that achieves the required purity of natural gas at different flow rates and compositions of feed stream. Steady state calculation for the plant was carried out in CHEMCAD. Dynamic simulation is conducted to see how changes in flow rate and composition of feed stream influence the process of purification. Process control was designed within CHEMCAD's dynamic mode and dynamic behavior of the process to flow and composition changes of feed stream was analyzed. Simulation study included 10 control circuits that regulate key variables and maintain the stability of the process. Process response to flow and composition change of feed stream was monitored. Regulated variables and purity of the product were analyzed. Based on the research results a conclusion was made on the stability of the process in terms of changes in the composition and quantity of feed stream, as well as the possibility to maintain the required purity of the product despite the dynamic changes in the process