Dynamic simulation for the production of dimethyl ether from natural gas

It is known that dimethyl ether (DME) has wide application, such as solvent, propellant, chemical intermediate, refrigerant replacement, LPG substitute and transportation fuel. Recently, DME has attracted attention as an alternative fuel for diesel engines and LPG substitute. Moreover, because it can emit much less pollutants such as CO, NO_x and particulates, dimethyl ether really meets the standards for clean fuel. In the future, DME will be much used in fuel industries. In the previous studies, a preliminary process flowsheet for direct synthesis of DME from synthesis gas has been built on commercial process simulator platform. This work tries to study the technical potential for producing DME from natural gas. The production of DME from natural gas can be divided by two reaction processes. The first reaction is production of syngas by natural gas and the second is production of DME from syngas. In this study, the kinetics of the first reaction process shown in the literature is first studied. The optimal feed conditions are then determined by the commercial process design simulator. According to the optimal operation conditions of the second reaction process provided by Chen (2008), the steady-state process flow diagram of this DME process can be obtained. After combining the separation and recycle units, the control loop interactions are analyzed and suitable PI controller parameters are tuned for the overall DME process. Finally, the simulation results for setpoint tracking and disturbance rejection demonstrate the effective performance of the proposed control system design for the production of DME from natural gas.