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Energy‐Efficient Methanol to Dimethyl Ether Processes Combined with Water‐Containing Methanol Recycling: Process Simulation and Energy Analysis
Author(s) -
Zhang Chundong,
Jun KiWon,
Kwak Geunjae,
Kim Sungtak
Publication year - 2019
Publication title -
energy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 44
eISSN - 2194-4296
pISSN - 2194-4288
DOI - 10.1002/ente.201800469
Subject(s) - methanol , dimethyl ether , chemistry , dehydration , catalysis , methanol reformer , waste management , materials science , process engineering , environmental science , chemical engineering , organic chemistry , steam reforming , engineering , hydrogen production , biochemistry
Two methanol‐to‐dimethyl ether (MTD) process scenarios were proposed to develop new MTD processes with improved energy efficiency by recycling water‐containing methanol to the MTD reactor. In both scenarios, a water‐tolerant K‐modified H‐ZSM‐5 was used in the MTD reactor as the methanol dehydration catalyst. Process modeling was implemented by using Aspen Plus to obtain the quantitative energy analysis results. Both scenarios are mainly comprised of a methanol preheating unit, a methanol dehydration unit, a DME separation unit, a methanol separation unit, and a methanol recycling unit. The two modelled scenarios have differing flow paths of the methanol recycle stream. That is, in option 1, after separating DME, a portion of the water‐containing methanol was recycled directly to the MTD reactor without entering the methanol separation unit. Whereas, in option 2, all of the water‐containing methanol was sent to the methanol separation unit. However, the less‐purified methanol was obtained and recycled. The process performance of both proposed scenarios was investigated by varying the recycle ratio or the recycled methanol purity in scenarios 1 and 2, respectively. Compared with the conventional γ ‐Al 2 O 3 based MTD process, both of the proposed scenarios were found to be more beneficial in saving both energy and capital cost, which can be seen from the high energy saving rate and smaller equipment size of the separation units in the newly proposed MTD process scenarios 1 and 2.