Measuring temperature of methanol-to-olefins catalyst bed by use of electrical capacitance tomography
As a key step in the production of olefins from coal,the methanol-to-olefins(MTO)process is of significant importance in coal chemical industry.Since MTO is an exothermic reaction,it is necessary to monitor the temperature distribution in the bed to im-prove the conversion of methanol and selectivity of products.In this study,a method was proposed for online monitoring of the catalyst bed temperature(DMTO industrial catalyst,ZSM-5 zeolites)using high-temperature electrical capacitance tomography(ECT)imaging.By comparing the measurement results with different bed materials such as quartz sand and alumina,which have a minimal change in rela-tive permittivity with temperature,It is found that the relative permittivities of catalyst and zeolites vary with temperature,and thus the measured capacitance between electrodes are sensitive to temperature in the catalyst bed.Therefore,the temperature of the bed can be measured by averaging the normalized capacitance of the bed with uniform temperature distribution through the high-temperature ECT.This method was veritied by an online temperature measurement for DMTO catalyst and ZSM-5 zeolites in a thin-walled quartz fixed bed reactor,and further showed that the ECT images reconstructed using the linear back projection algorithm might be used to obtain the tem-perature distribution in the bed.Therefore,the fixed bed bed tempe rature can be measured by high-temperatur ECT.
methanol-to-olefinszeolite catalyston line measurementelectrical capacitance tomographytemperature
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