466479 Synthesis of Dimethyl Ether from Natural Gas: CO2 Utilization Process
The two main steps required to produce DME from natural gas are: syngas has to be synthesized first, followed by a direct reaction combing production and dehydration of methanol to make DME. The production of syngas in the first step is carried out through tri-reforming since carbon production could be avoided and thus the catalyst is protected from poisoning. In the following step, the H2/CO ratio is adjusted to avoid water-gas shift reaction, which makes CO2as side-product instead of water.
The whole project is divided into twelve different tasks , in which different design decisions are made in a hierarchical manner. First, all the information about products and selected synthesis process are collected and an initial processing path synthesized in tasks 1-3. Then, the preliminary design decisions for the main design variables are made and verified through simple mass balance based simulations in task 4. Then, both energy and mass balance are verified through a process simulator (PROII) using simple as well as rigorous simulation models in tasks 5-7. At this point, a preliminary synthesis-design of the process is obtained. The next tasks (8-9) involved the sizing and costing calculations to establish a base case design. In the final tasks (10-12), the base case design is analyzed and targeted improvements are made through optimization, heat integration, and environmental impact analysis  to obtain a more sustainable and improved process design. A net carbon dioxide emission for this process is also calculated. Based on the design, twenty thousand metric tons of DME, with a 99.7% purity, are produced per year.
In this work PROII is used for simulating the process, while ECON is applied for economic evaluation. Also many other tools are used: ICAS  for additional property prediction, SustainPro  for sustainability analysis and process “hot-spot” (bottleneck) identification and LCSoft  for lifecycle assessment factor and environmental indicators, including the ECO efficiency indicators.
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