Problem Diagnosis And Optimal Operation Of A Natural Gas Decarburization Unit With Lean And Semi-lean Amine Solution

In recent years,natural gas as a high-quality clean energy has obtained unprecedented development,different carbon content of natural gas purification process is different,it is necessary to make a reasonable choice according to the content of CO₂ in natural gas.The conventional decarburization process of total lean amine solution amine is widely used in the field of requiring deep decarbonization.One stage absorption and one stage regeneration process is adopted.The regenerating heat of the system is supplied by reboiler,and the heat consumption is large.When the carbon content of natural gas is higher than 10%（CO₂>10%）and the purification effect is low required,for energy saving and reducding consumption,the decarburization process of natural gas is usually adopted by segmented absorption,that is,lean amine and semi-lean amine solution.At present,the research on the decarburization process of lean and semi-lean natural gas is concentrated in the field of high carbon content,more and more existing processes are transformed into lean and semi-lean amine solution cycle process by means of simulation to achieve the effect of saving energy and reducing consumption.With the development of high carbon-bearing gas field,the application and research of lean and semi-lean amine solution decarbonization technology becomes more and more important.In this study,taking a lean and semi-lean amine solution natural gas decarburization unit as an example,the problem diagnosis and optimal operation of the lean and semi-lean amine solution decarburization unit are carried out by means of mechanism experiment and HYSYS simulation.The key factors of optimizing operation in semi-lean amine solution process were determined,and the screening and evaluation method of ternary amine solution under semi-lean amine solution process was established.Through the sensitivity analysis of process parameters under single factor,the relationship between reboiler temperature and stripping steam quantity,stripping steam temperature,inlet temperature of semi-lean amine solution,rich amine solution temperature and amine solution formulation is obtained.Through the mechanism experiment and HYSYS simulation,the selection and evaluation index of semi-lean amine solution process amine solution was determined.The existing amine solution formulation was optimized under different total amine concentration and absorption regeneration temperature,and the HYSYS simulation process parameters were optimized on the basis of optimized formulation.The results show that the optimal circulation capacity of lean amine solution exceeds the equipment capacity and the optimization space is limited.In order to reduce the cost and increase the efficiency,further optimization of ternary high efficiency amine absorbent under semi-lean amine solution process was carried out,and the screening and evaluation indexes of ternary amine solution under semi-lean amine solution process were formed:absorption rate,absorption load,desorption rate,and so on,in which absorption rate,absorption load,desorption rate and desorption rate were selected and evaluated.Compared with the regeneration energy consumption and saturated capacity of CO₂,a ternary compound amine formulation with the best comprehensive performance was obtained by combining the cycle performance and foaming property.