Simulasi absorpsi multikomponen gas dalam larutan K2CO3 dengan promoter MDEA pada packed column

Abstract

Simulation of multi-component gas absorption in the K₂CO₃ solution with promoter MDEA in packed column This research aims to study theoretically the performance of packed column to absorb CO₂ and H₂S from acid gas using MDEA promoted K₂CO₃ solution by considering solubility of other gases. Performance is expressed as CO₂ recovery percentage. Research was carried out by developing simulation program of gases absorption with chemical reaction in packed column under isotherm condition. Prediction results were validated with petrochemical plant data. The simulation program can predict concentration distribution of dissolved gases and reactants in liquid phase at packed column and also the percentage of CO₂ and H₂S recovery. Results show that CO₂ and H₂S recovery increase with the increasing pressure and liquid flow rate. The study also depicts presence of an optimum temperature where CO₂ recovery increases with increasing temperature below optimum temperature and decrease with increasing temperature above optimum temperature. The absorption rate increase or decrease with increasing temperature depending on relative effect of temperature on reaction rate, gas diffusivity and solubility. For CO₂ absorption into MDEA promoted 30% K₂CO₃ solution at packed column 3 m in diameter, and 30 m in height filled with 7 cm IMPT packing, the highest CO₂ removal efficiency is 99.947% on 100 ^oC, 32 atm, liquid flow rate of 5900 m³/hr, and gas flow rate of 308 kNm³/hr.

Keywords: reactive absorption, isothermal, multi-component, promoter, two-film model

Abstrak

Penelitian ini bertujuan untuk mempelajari secara teoritis kinerja packed column untuk absorpsi CO₂ dan H₂S dari gas asam dengan larutan K₂CO₃ dan promotor MDEA dengan memperhatikan kelarutan gas-gas yang lain, yang dinyatakan dengan %-recovery CO₂. Penelitian ini dilaksanakan dengan membuat program simulasi untuk absorpsi gas CO₂ disertai reaksi kimia dalam kondisi isothermal. Hasil prediksi simulasi ini divalidasi dengan data lapangan. Dengan menggunakan model packed column ini, diperoleh distribusi konsentrasi gas-gas terlarut, distribusi konsentrasi reaktan dalam fasa cair dalam kolom absorber dan prediksi %-recovery CO₂ dan H₂S. Hasil penelitian menunjukkan bahwa semakin tinggi tekanan dan laju alir absorben %-penghilangan CO₂ dan H₂S semakin besar. Hasil penelitian menunjukkan adanya suhu optimum. Di bawah suhu optimum kenaikan suhu menyebabkan kenaikan %-penghilangan sedangkan di atas suhu optimum kenaikan suhu menurunkan %-penghilangan. Laju absorpsi meningkat tergantung pada pengaruh relatif temperatur pada konstanta kecepatan reaksi, difusivitas dan kelarutan gas yang terserap. Untuk absorpsi gas CO₂ kedalam larutan K₂CO₃ 30% dengan promotor MDEA pada packed column dengan diameter 3 m dan tinggi 30 m yang diisi dengan packing IMPT 7 cm diperoleh penghilangan CO₂ tertinggi 99,947% pada kondisi laju alir larutan 5900 m³/jam, temperatur 100 oC, laju alir gas 308 kNm³/jam serta tekanan 32 atm.

Kata kunci: absorpsi reaktif, isothermal, multikomponen, promoter, model dua film.