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Total Concentration Profile along Reactor Length
Posted 19.02.2011, 00:04 GMT-5 1 Reply
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Hi,
I am trying to model a reaction along a plate coated with catalyst (ie three subdomains - gas channel, catalyst layer and conducting wall) and realized that the total concentration along the reactor length (ie sum of species concentration variables) actually increases along the reactor length as temperature increases (pressure drop is not significant). In this case five species concentrations are considered for Convection and Diffusion application mode: c_ch4, c_h2, c_co, c_co2 and c_h2o, ie total conentration = c_ch4+c_h2+c_co+c_co2+c_h2o.
According to the ideal gas law, c = p/RT, the total concentration should in fact decrease along the plate length with increasing temperature, where p is the total pressure. Interestingly, when plotting p/RT (where p and T are variables) using Post Processing along the length, it decreases as expected. However, would expect this to be the same as explicitly summing the species concentrations as mentioned in the first paragraph, which isn't the case.
Thanks in advance.
I am trying to model a reaction along a plate coated with catalyst (ie three subdomains - gas channel, catalyst layer and conducting wall) and realized that the total concentration along the reactor length (ie sum of species concentration variables) actually increases along the reactor length as temperature increases (pressure drop is not significant). In this case five species concentrations are considered for Convection and Diffusion application mode: c_ch4, c_h2, c_co, c_co2 and c_h2o, ie total conentration = c_ch4+c_h2+c_co+c_co2+c_h2o.
According to the ideal gas law, c = p/RT, the total concentration should in fact decrease along the plate length with increasing temperature, where p is the total pressure. Interestingly, when plotting p/RT (where p and T are variables) using Post Processing along the length, it decreases as expected. However, would expect this to be the same as explicitly summing the species concentrations as mentioned in the first paragraph, which isn't the case.
Thanks in advance.
1 Reply Last Post 07.03.2011, 22:36 GMT-5
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Posted:
1 decade ago
Hi,
I was still having this problem and was wondering if anyone had any insights. Am starting to think this is a numerical error as it works in the 1D case but not necessarily 2D. Attached is a sample graph of the total concentration profile along the length of the reactor channel using sum of species concentrations and using ideal gas law; p/R/T. Thanks.
I was still having this problem and was wondering if anyone had any insights. Am starting to think this is a numerical error as it works in the 1D case but not necessarily 2D. Attached is a sample graph of the total concentration profile along the length of the reactor channel using sum of species concentrations and using ideal gas law; p/R/T. Thanks.
Attachments: