Physical and Chemical Principles of Increasing the Efficiency of the Methanol Desorption Process

During the extraction and low-temperature preparation of natural gas for transportation, water–methanol solutions are formed in concentrations of 30–60 wt %. High efficiency of methanol extraction from them and, thus, reduction of operating costs for industrial wastewater treatment can be achieved by using desorption processes. In this paper, the physicochemical principles of the technological process of methanol desorption from water–methanol solutions during the preparation of natural gas for transportation are considered. For this purpose, the phase behavior of a three-component mixture consisting of methane, methanol, and water is studied. The influence of the main factors affecting the process of methanol desorption from a water–methanol solution by primary separation gas is investigated (temperature, pressure, flow rate, and concentration of methanol in the irrigation flow), as well as the configuration of the low-temperature separation unit. It is shown that desorption in gas treatment units for transportation is carried out in the area of conditions that are non-optimal from the point of view of the technological process. This is due to the fact that the process under consideration is auxiliary in relation to the low-temperature preparation of the extracted reservoir product. Recommendations are given for optimizing the operation of existing gas preparation units and for the configuration of prospective gas preparation facilities.