I want to take two material streams: the fuel and oxidant. These two streams enter to an unit, block (cell) or to receive a tool and one output stream. output flow will contain products of combustion.
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Hi Vitaly
if you use a chemical reactor model you can do the same. With that you also get the energy balance for "free". In ExcelUO you will have to do that inside your own calculations with Excel.
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You're right Greg, I thought about the Excel UO if he intends to use a different reaction model... but if it is a simple combustion, he can use the Conversion Reactor to do that.
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I am new to DWSIM (about three weeks) and must congratulate Daniel and others on this product. I have already been able to model a steam reformer (process and furnace sides), which is an indication of how easy it is to use. With that much already, it is only a day or two till I have a complete hydrogen plant.
There is one thing that I find missing, and that is creating a fuel component (coal, heavy oil or biomass). This is a limitation for my work and reading the discussions, I am clearly not the first with this problem.
For these fuels, usually the information available from a client is an ultimate analysis (C, H, O, S, N) by weight percent and a heating value. Specific enthalpy if not defined by the client can be assumed with a literature value. The difficulty is that a routine is needed to convert this information into a form useable by the rest of DWSIM – particularly the reactors (Gibbs for gasification or Conversion for combustion). I have my own .vb and VBA routines for gasification and combustion which work with only this data, so I know it to be possible.
Has anyone already made such a routine? If so, where can I find it? Otherwise, I may have to develop my own add-on, but that could take some time.
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What I usually do when I have to work with unknown substances is to try to find a representative formula for the whole, like for instance with linear hydrocarbons (CxHx+2) and enter the UNIFAC structure in the compound creator. If you don't have any idea how the molecule looks like, you can enter the amount of elements directly using the Joback table.
Regards,
Daniel
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Dear Daniel,
many thanks for the suggestion. I have tried to put a Pittsburgh #8 coal in using Joback, but the results are exotic to say the least. The ultimate analysis (in wt%) of the dry, ash-free coal is C - 84.218, H – 5,592, O - 6.162, S – 2.431, N – 1.598. In my own model I assign an arbitrary molecular weight of 100 kg/kmol, so the chemical formula results in C7.018H5.592O0.385S0.076N0.114. But Joback does not accept fractions, so to obtain the correct ratios between the elements, I must use C185H147O10S2N3 with a molecular weight of 2633 kg/kmol.
For such a “molecule” using the HHV of the coal 31,268 kJ/kg, my manual calculation of the heat of formation is -176,798 kJ/mol.
I am also having problems with entering solid density (1500 kg/m³) and solid heat capacity (1.4 kJ/Kg.K). I have watched the YouTube instructions, but my rudimentary Portuguese may have caused some misunderstanding.
Best regards,
Chris
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Good day! Help me, please. How I can calculate in DWSIM process full fuel combustion?
Last edit: vitaliy 2015-01-17
Can you give us more details about what you want to do?
I want to take two material streams: the fuel and oxidant. These two streams enter to an unit, block (cell) or to receive a tool and one output stream. output flow will contain products of combustion.
You can use the excel unit operation to do that, writing your model in a spreadsheet. What are the fuel components?
Hi Vitaly
if you use a chemical reactor model you can do the same. With that you also get the energy balance for "free". In ExcelUO you will have to do that inside your own calculations with Excel.
You're right Greg, I thought about the Excel UO if he intends to use a different reaction model... but if it is a simple combustion, he can use the Conversion Reactor to do that.
I am new to DWSIM (about three weeks) and must congratulate Daniel and others on this product. I have already been able to model a steam reformer (process and furnace sides), which is an indication of how easy it is to use. With that much already, it is only a day or two till I have a complete hydrogen plant.
There is one thing that I find missing, and that is creating a fuel component (coal, heavy oil or biomass). This is a limitation for my work and reading the discussions, I am clearly not the first with this problem.
For these fuels, usually the information available from a client is an ultimate analysis (C, H, O, S, N) by weight percent and a heating value. Specific enthalpy if not defined by the client can be assumed with a literature value. The difficulty is that a routine is needed to convert this information into a form useable by the rest of DWSIM – particularly the reactors (Gibbs for gasification or Conversion for combustion). I have my own .vb and VBA routines for gasification and combustion which work with only this data, so I know it to be possible.
Has anyone already made such a routine? If so, where can I find it? Otherwise, I may have to develop my own add-on, but that could take some time.
Hi Chris,
What I usually do when I have to work with unknown substances is to try to find a representative formula for the whole, like for instance with linear hydrocarbons (CxHx+2) and enter the UNIFAC structure in the compound creator. If you don't have any idea how the molecule looks like, you can enter the amount of elements directly using the Joback table.
Regards,
Daniel
Dear Daniel,
many thanks for the suggestion. I have tried to put a Pittsburgh #8 coal in using Joback, but the results are exotic to say the least. The ultimate analysis (in wt%) of the dry, ash-free coal is C - 84.218, H – 5,592, O - 6.162, S – 2.431, N – 1.598. In my own model I assign an arbitrary molecular weight of 100 kg/kmol, so the chemical formula results in C7.018H5.592O0.385S0.076N0.114. But Joback does not accept fractions, so to obtain the correct ratios between the elements, I must use C185H147O10S2N3 with a molecular weight of 2633 kg/kmol.
For such a “molecule” using the HHV of the coal 31,268 kJ/kg, my manual calculation of the heat of formation is -176,798 kJ/mol.
I am also having problems with entering solid density (1500 kg/m³) and solid heat capacity (1.4 kJ/Kg.K). I have watched the YouTube instructions, but my rudimentary Portuguese may have caused some misunderstanding.
Best regards,
Chris
try something like this