Calculation of conversion rate and specific consumption in methanol synthesis towers
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I would like to ask the experienced experts on this forum. The Luchi technology synthesis tower was originally designed to handle a syngas flow rate of 258,042 Nm³/h (at a pressure of 5.3 MPa) from the upstream unit, as well as a hydrogen flow rate of 18,090 Nm³/h (at a pressure of 5.3 MPa) from the hydrogen production unit. The gas is then pressurized to 8.9 MPa by compressors before entering the synthesis tower for reaction. The methanol production rate is 125 t/h. The consumption of syngas per unit of product is 2064 Nm³/t. At the current stage, the amount of syngas supplied from the upstream units is 79292 Nm³/h (at a pressure of 4.0 MPa); this syngas is then pressurized to 5.1–5.7 MPa using compressors before being fed into the synthesis tower for reaction. Under these conditions, the production rate is 43 t/h, with a syngas consumption of 1844 Nm³/t. Assuming there are no errors in the instrument measurements, I would appreciate it if experienced experts could help analyze the reasons behind this situation, as well as provide guidance on how to calculate the conversion ratio and syngas consumption at different load levels and pressures. Could the expert Aspen on the forum give some guidance on the modeling process? Thank you
It worked fine when I was typing it, but when I uploaded it, the unit ‘per hour’ in my formula turned into a bunch of symbols. Please forgive me. Those in the field know it!
The conversion rate and specific consumption of the methanol synthesis tower are influenced by various factors, including the composition, pressure, and flow rate of the feed gas, as well as the catalysts inside the synthesis tower and the operating conditions. Based on the data you provided, the original design results in lower flow rates and pressures compared to the current level, which is likely the main reason for the decrease in specific consumption. The conversion rate and specific consumption can be calculated following these steps: 1. Calculate the Conversion Rate: The conversion rate can be defined as the ratio of the number of moles of reactants before the reaction to the number of moles of products formed after the reaction. The specific calculation formula is: Conversion rate = (Moles of feed – Moles of output) / Moles of feed * 100%. 2. Calculation of specific consumption: Specific consumption is generally defined as the amount of raw material (such as syngas) required to produce one unit of product (such as methanol). The specific calculation formula is: specific consumption = total feed amount / output. Under different pressures and loads, the operating efficiency of the synthesis tower may vary, which affects the conversion rate and specific consumption. Process parameters can be adjusted or detailed simulations can be carried out using simulation software such as Aspen Plus, in order to optimize operating conditions and predict performance under different conditions. In the modeling process within Aspen Plus, you need to set up the correct material flows and reaction mechanisms, enter appropriate operating conditions (such as temperature, pressure, reactor type, etc.), and then conduct simulation calculations to analyze the impact of various parameters on the performance of the synthesis tower. You can refer to the Aspen Plus user manual or online tutorials to learn* how to create models and conduct simulations. .
There should be a composition for incoming and outgoing materials. Or selectively, conversion rate data is required.
Yes, reactions, side effects, products, and so on all need to be taken into consideration