**3.3 DME synthesis**

In 1991, a 10 t/d pilot-scale plant for synthesizing DME from syngas in a slurry bed was developed by Air Products and Chemicals, Inc., and Cu-based methanol synthesis catalysts and methanol dehydration catalysts γ-Al2O3 were adopted. Taiyuan University of Technology, Tsinghua University and Shanxi Coal Chemical Institute of Chinese Academy of Sciences have also done leading research work on slurry bed for DME synthesis. The catalyst for the one-step synthesis of dimethyl ether in the synthesis gas slurry bed is similar to the one-step catalyst in the fixed bed, which includes a methanol synthesis catalyst and a methanol dehydration catalyst. The methanol synthesis catalyst generally adopts CuZnAl catalyst or modified CuZnAl catalyst, and the catalyst for methanol dehydration generally adopts γ-Al2O3, zeolite, etc. **Table 2** summarizes the progress of DME synthesis in a slurry-bed reactor [24]. It can be seen that JFE (formally NKK) Corporation produced DME while Air Products Chemicals produced DME and methanol.
