Pra-Rancangan Pabrik Dimetil Eter (DME) dari Batang Tembakau Via Metode Indirect Synthesis dengan Kapasitas 18,000 Ton/Tahun

Abstract

Dimethyl ether (DME) is an aliphatic ether with physical and combustion properties comparable to liquefied petroleum gas (LPG), enabling its application as an alternative fuel, blending component, and chemical intermediate. The increasing demand for LPG and reliance on imported supplies highlight the need for renewable energy sources derived from domestic resources. Biomass-based DME production offers a strategic approach to improving energy sustainability while addressing agricultural waste utilization. This study presents the design of a DME production plant with a capacity of 18.000 tons per year using tobacco stalk as the main feedstock. Tobacco stalk contains significant lignocellulosic content suitable for conversion into synthesis gas (syngas). The indirect synthesis route is selected due to its operational stability and lower catalyst deactivation compared to direct synthesis methods. The process consists of six major stages. Initially, the feedstock undergoes pretreatment through size reduction and drying. The prepared biomass is then gasified in a downdraft gasifier to produce syngas. The syngas is subsequently converted into methanol by reaction with a CuO/ZnO/Al2O3 catalyst. Methanol purification is carried out using a distillation column to separate water and obtain methanol with a purity of 99%. The purified methanol is then dehydrated over a γ-Alumina catalyst to synthesize DME. The final purification step employs a distillation column to obtain DME with a purity of 99%. Material balance results indicate that 2.277,84218 kg of DME per hour can be produced from 7.490,829 kg per hour of tobacco stalk biomass. Economic evaluation shows a net profit of Rp153.546.834.350, a return on investment of 15%, and a payback period of 4,28 years. The break-even point is achieved at 48% of plant capacity. These results confirm that the proposed DME plant is economically feasible and has the potential to reduce LPG import dependency while promoting renewable biomass utilization.