Development of MEG Regeneration Unit Compatible Corrosion Inhibitor for Wet Gas Systems

Abstract

Transportation of hydrocarbons and water in long subsea flow lines from satellite fields to a platform or to an onshore facility presents new challenges in the control of gas hydrates, corrosion, and mineral scale. Gas hydrates form at high pressure and low temperature and are a common problem in offshore wet gas pipelines due to low seabed temperatures and elevated pressures in these remote subsea developments. Monoethylene glycol (MEG) is widely used as a thermodynamic hydrate inhibitor in these developments to manage the risk of hydrate formation during production and transportation of multiphase fluids from subsea wells. Due to large amounts of MEG required for effective hydrate control, it is necessary to recycle and re-use it. The main processes for recycling of MEG are regeneration and reclamation. Typical conditions of regeneration and reclamation processes are ambient to vacuum pressures and temperatures in the range of 120°C −150°C1. In addition to the use of MEG for hydrate control, corrosion inhibitors are also applied for corrosion control in the subsea pipelines and infrastructure. These corrosion inhibitors must be able to perform under high shear and highly corrosive environments without losing their effectiveness after having been subjected to the system conditions present in the MEG regeneration process. Inappropriate selection of corrosion inhibitors for MEG based applications can lead to severe fouling/formation of solids, emulsion and foaming issues in the receiving facilities. The corrosion inhibitors developed for use in facilities operating with glycol regeneration systems should remain active after multiple MEG Regeneration Unit (MRU) cycles without causing fouling/formation of solids, emulsion and foaming. The current paper presents MRU compatible corrosion inhibitors developed based on the stringent testing methods adopted from real time MRU process.

Experimental investigation and kinetic modeling of nanocrystal growth for scale reduction in mono-ethylene glycol regeneration unit

“…Moreover, the RMSD and MARE% of these equations in predicting the length of crystals were calculated for each concentration of nanoparticles using Eqs. (17) and (18): These results of errors are reported in Table 5. It is obvious that there is a very good agreement between experimental results and developed model of crystal growth.…”

“…Crystal growth of CaCO 3 in mixed MEG water solvent was studied by Flaten et al [12], and its impact on the performance of re-boilers was tested by Kananeh et al [13]. Moreover, the impact of using different kinds of inhibitors like hydrate, scale, and corrosion inhibitors on scaling under oilfield condition was discussed, as an inappropriate selection of these chemicals can lead to severe fouling, foaming, and emulsion issue in the facilities of MEG line [6,[14][15][16][17][18].…”

“…Two main types of corrosion inhibition techniques are using pH stabilization agents or corrosion inhibitors. The use of a pH stabilization motivates salts precipitation and scaling by elevating pH of fluids and corrosion inhibitors may be incompatible with MEG reclaiming unit resins or cause a malfunction in other equipment due to the formation of sticky sludge or scales, emulsion, and foaming issues or maybe degraded at high temperature during regeneration of MEG [17]. Therefore, the application of different production chemicals throughout a MEG loop can cause more scaling problems, while the current methods have not been successful yet.…”

Recovery of mono-ethylene glycol by distillation and the impact of dissolved salts evaluated through simulation of field data

“…Mono-ethylene glycol (MEG) is an important raw material having numerous research and industrial applications, one such example is its application as a hydrate inhibitor in the hydrocarbon processing industry (Lu, Kan, and Tomson 2010). MEG is one of the most favoured thermodynamic hydrate inhibitors used in hydrocarbon transportation pipelines and processing facilities due to its low volatility, low toxicity, low flammability, favourable thermodynamic behaviour, simple and proven technology requirements and high availability (Bikkina et al 2012, Haque 2012). Furthermore, the preference for using MEG over other traditional thermodynamic hydrate inhibitors such as methanol stems from several operational, environmental and safety issues imposed by the use of methanol and MEG's ability to be effectively recovered, regenerated and reused (AlHarooni et al 2015, Haghighi et al 2009).…”

“…The most prevalent MEG recovery methods have been broadly categorised into two main process types, (i) reconcentration and (ii) regeneration (Bikkina et al 2012). The reconcentration process is the most basic MEG recovery method and is comprised of a simple distillation column where the water rich MEG is concentrated to form lean MEG by vaporisation of the excess water.…”