| Popis: |
Although multi-component phase changes are frequently present in petrochemicals, gas processing industries, cryogenic applications and chemical industries where distillation, stripping, etc., are common, most literature on heat exchanger network synthesis (HENS) assumes isothermal phase changes only. However, multi-component phase change occurs over a range of temperatures and the temperature–enthalpy (T-Q) relations are highly nonlinear. In such cases, isothermal approximations lead to suboptimal or even inaccurate networks. To this end, we present an MINLP model using a second order T-Q correlation that rigorously accounts for multi-component phase changes in HENS problem. It is shown that incorporating multi-component phase changing streams in the network reduces the total annualized cost of the network and improves the overall energy savings. In doing so, it is also possible for multi-component condensers and reboilers to become part of the plant-wide heat integration. |
