Simulation of Hydrate Phase Boundary for Natural Gas Mixture with High CO2Content through Simulation

Abstract

Gas hydrates are solid crystalline structures in which water molecules trap small guest gas molecules and encage them through hydrogen bonding. Gas hydrates are known to be problematic in flow assurance applications as they can form plug inside the pipelines during oil and gas production, transportation and processing. In order to inhibit hydrate formation thermodynamically, various chemicals including some alcohols e.g. methanol (MeOH), mono- ethylene glycol (MEG) are used as thermodynamic hydrate inhibitors (THIs). In this paper, a simulation study is performed using PVTsim software wherein it predicts the hydrate formation for pure CO2 solution mixture and CO2 -MEG solution mixture systems using different equation of states. These equations of states include Soave-Redlich-Kwong (SRK), SRK-Peneloux, Peng- Robinson (PR) and Peng-Robinson Peneloux. The simulation results obtained using these equation of states were validated with the experimental data and PRPenelouxEoS was found to be in better agreement. The hydrate formation regions are determined in between the pressure range of 10 to 110 bara for natural gas mixture containing high percentage of CO2 in it. The inhibitors are used in 5, 10 and 20 wt% concentrations. The hydrate inhibition efficiency increased with the increase in concentration. Simulation results showed that methanol performed better in comparison to the other inhibitors at all concentrations.

Removal of Carbon Dioxide and Hydrogen Sulfide from Natural Gas Using a Hybrid Solvent of Monoethanolamine and N-Methyl 2-Pyrrolidone

“…Hybrid solution that effectively removes acidic gases by utilizing the advantages of physical or chemical solvents in various ways . These advantages include the ability to absorb CO 2 without being limited by stoichiometry, the ability to yield a higher purity for treated gas, lower circulation flow rate and energy requirements for regenerating the solution, reduced costs of gas pressure amplification by avoiding hydrate formation at low temperatures, and control of corrosion and contaminant dispersion within permissible limits. − …”

Application of Gaussian Process Regression (GPR) in Gas Hydrate Mitigation

“…It is an ice-like, non-stochiometric crystalline mixture made up of a water cage frame dominated by gas molecules like methane, CH4, ethane, C2H5, and carbon dioxide, CO2, that forms solid particles that takes place under high pressure and low temperature conditions [3][4][5][6]. Gas hydrates are produced in the petroleum and natural gas industries' output, refining and transmission facilities [8][9][10].…”

“…The purpose of THIs, also like water-ice antifreezes, is to disrupt the mechanism in which hydrates develop. In conjunction, the function of KHI is to delay crystallisation of hydrate and the function of AAs is to promote distortion of hydrate molecules [10]. Conversely, because of improvement in deep-sea pipeline placement, the use of THIs is not effective because it creates high operational and capital expense (CAPEX) relative to LDHIs that are more cost-effective [1,13].…”

“…Advance management approach is the implementation of expertise focused on predictive study of multiphase flow, fluid chemistry, hydrate kinetics and plugging processes that do not require power calculation [10]. The use of Machine Learning (ML) is an innovative risk control technique that is currently being applied.…”