Optimization strategy for long-term catalyst deactivation in a fixed-bed reactor for methanol synthesis process Mohd Nazri Mohd Fuad, Mohd Azlan Hussain, Adam Zakaria 1. Introduction Methanol is a chemical building block that is widely used in the manufacturing of many consumer and household products. Formaldehyde is the single largest consumer of methanol in the world, accounting for around 37% of global demand followed by MTBE (11%) and acetic acid (10%). Methanol is also a common laboratory solvent, especially useful for high performance liquid chromatograph, ultraviolet–visible spectroscopy, and liquid chromatography–mass spectrometry due to its low ultraviolet cutoff. Recently, methanol has also emerged as an important alternative energy fuel to replace fossil fuels in the transportation and power generation sectors (Olah, Goeppert, & Surya Prakash, 2009). In this proposed methanol economy, methanol will become the efficient means for energy storage, transportation, and also a convenient fuel in its own right due to its liquid property in the ambient conditions. For instance, in direct-methanol fuel cell, methanol is directly oxidized with air to carbon dioxide and water to produce electricity, without the need to generate the hydrogen. It is expected that the demand for methanol will continue to increase in the near future, driven in large part by the resurgence of the global housing markets and increase demand for cleaner energy. Methanol synthesis is among the important catalytic reaction processes in the petrochemical industry. Methanol is generally synthesized from synthesis gas, a mixture of CO, CO2 and H2 that is produced largely from the natural gas steam reforming process. The process route for the production of methanol is relatively simple and comprises of the following three major steps: (1) production of synthesis gas, (2) conversion of synthesis gas into methanol, and (3) distillation of the reactor product to obtain the required product specification. The production of methanol from the synthesis gas usually takes place in a tubular reactor with the assistance of a catalyst (Tijm, Waller, & Brown, 2001). Methanol synthesis process is generally categorized between two classifications according to the pressure used. High pressure process (250–300 bar) uses a relatively poison resistant ZnO/Cr2O3 as the methanol synthesis catalyst. The drawbacks of high pressure processes are related to the significant investment in the plant design and operating costs as high pressure processes will require thick-walled vessels and