CO2 corrosion has become a problem that can not be ignored for the deepwater natural gas pipeline. At present this is difficult to simulate the low water content and the high gas flow velocity for natural gas field in the deep water by the traditional evaluation method of corrosion inhibitor in the laboratory and the accuracy of experimental results is questionable. In this paper laboratory simulation of actual natural gas field conditions was carried out using traditional rotating cylinder electrodes and self-made wet gas flow loop via considering the wall shear stress and mass transfer function as the hydrodynamic parameters to equivalent actual working conditions and laboratory conditions. The effect of corrosion inhibitor in high gas flow velocity was evaluated by using the weight loss test the Microcor ER probe and the self-made electrochemical probe respectively. By comparing the evaluation results of above methods the advantages and disadvantages of each method are analyzed at same time the most suitable method and process for the evaluation of corrosion inhibitors are screened and formulated in deepwater natural gas pipelines. In addition it provides the theory and data support for the evaluation of the corrosion inhibitor in deepwater natural gas field.
Duplex stainless steel (DSS) is a material in the issue as it’s very excellent in corrosion resistance mechanical properties weldability in various environments as compared with common materials. Due to these characteristics DSS is applied to various industries such as petrochemical facilities offshore structures power plants etc. However since duplex stainless steel is expensive it has a limitation that it is difficult to apply it to equipment that needs to be replaced periodically. Compared to DSS lean duplex stainless steel (LDSS) has good formability and corrosion resistance while the reduced content of nickel molybdenum is superior in terms of economics. Therefore LDSS can be economically efficiently maintained and managed by applying it to equipment requiring periodic replacement such as a plate or a tube of a heat exchanger.At present in the district heating system a plate heat exchangers of austenitic SS material are installed and it is always exposed to chloride containing environments. Generally failures of the plate heat exchanger are occurred by the tap water of user side and it is mainly broken due to crevice induced corrosion cracking between the gasket and the heat exchanger pitting etc. As a result researches on localized corrosion of austenitic SS and DSS are actively underway in chloride containing environments. Whereas there are few researches on the localized corrosion behavior of LDSS in these environments. Therefore in this study we would like to evaluate the localized corrosion behavior of LDSS in the chloride containing synthetic tap water at 60 ℃ which is the operating condition of plate heat exchanger for district heating system.
To support installed tube lines, plastic clamp systems (which cause a high risk of corrosion failure of the pipe and tube) have been widely used. Crevice corrosion resistance of such was investigated based on the standard test methods. Characteristics were analyzed and operational life time estimated.
Seawater desalination with waste heat from nuclear or fossil power plants is an attractive alternative for the production of potable water.1 Multi-effect desalination process (MED) relies on the evaporation of water from a thin film of seawater.2 The heat of condensation is used in the evaporation of water from a subsequent film of seawater.