The Process Simulation Analysis And Revamp Research Of Complex Liquid-nitrogen Wash Unit

Besides the typical liquid-nitrogen wash column and related heat exchangers, a complex liquid-nitrogen wash also include tail gas and purge gas recovery system, which can recover a mass of H₂, CO dissolved in liquid-nitrogen and finally get 98% Ar product. Comparing to the typical liquid-nitrogen wash, the complex liquid-nitrogen wash have coupled preseparation, separation column and related exchangers, reflux tank and pump and so on. With the complex technology and integrated energy, these two coupled units make up of an advanced system, which is in favor of feedstock recovery and reuse, energy conversation and decreasing environment pollutionIn this task, the old complex liquid-nitrogen wash unit is introduced from a foreign corporation and rebuilt to rerun in a domestic corporation. The process simulation and equipment simulation of this unit have been discussed. Based on the profound comprehension of the process principle of unit, including separating sequence, matching heat exchanger network, concrete mass and heat transfer principle, the design and revamp case of this unit is simulated by ASPEN Plus software.First of all, the design case of complex liquid-nitrogen wash unit has been simulated and the column operation parameters have been got based on detailed analysis of design values of column and other unit. Improved RK-ASPEN thermodynamic model can exactly describe the process of thermodynamic behavior after sufficient analysis of physical properties and operation condition in low temperature and high pressure. The model of all flow has been set up by flow fracture and stream tearing based on every unit exact simulation in design case. The simulation results coincided with designed values quite well, suggesting the model is accurate and could be used in the research of revamp case.Secondly, a feasible and reasonable revamp scheme is proposed based on this kind of model which focus on feed gas changes from pulverized coal gas to coke oven gas, larger changes of the composition, no purge gas and high and low pressure nitrogen rate limit. This scheme is strictly simulated and profoundly analyzed on account of the composition changes. The column operation parameters have been respectively adjusted and the tail gas recovery system shutdown case has been simulated.At last, the equipment simulations have been done for design and revamp case including the tower hydraulics simulation and multi-stream plate-fin heat exchangers checking based on...