drying#

This module contains unit operations for drying solids.

class DrumDryer(ID='', ins=None, outs=(), thermo=None, **kwargs)[source]#

Create a drum dryer that dries solids by passing hot air (heated by burning natural gas).

Parameters:

  • ins (Sequence[Stream | str], optional) –

    • [0] Wet solids.

    • [1] Dry gas.

    • [2] Natural gas.

  • outs (Sequence[Stream | str], optional) –

    • [0] Dried solids

    • [1] Hot gas

    • [2] Emissions

  • split (dict[str, float]) – Component splits to hot gas (stream [1]).

  • RH (float, optional) – Relative humidity of hot gas as a fraction. Defaults to 0.80.

  • H (float, optional) – Specific evaporation rate [kg/hr/m3]. Defaults to 20.

  • length_to_diameter (float, optional) – Note that the drum is horizontal. Defaults to 25.

  • T (float, optional) – Operating temperature [K]. Defaults to 343.15.

  • moisture_content (float) – Moisture content of solids [wt / wt]. Defaults to 0.10.

Notes

The flow rate for gas in the inlet is calculated to meet the RH specification (i.e. relative humidity of hot gas depending on moisture_ID evaporated). The flow rate of inlet natural gas is also altered to meet the heat demand.

The default parameter values are based on heuristics for drying dried distillers grains with solubles (DDGS).

Examples

>>> import biosteam as bst
>>> from biorefineries import corn as c
>>> bst.settings.set_thermo(c.create_chemicals())
>>> feed = bst.Stream('feed', phase='l', T=352.33, P=101325,
...     Water=0.6749, Ethanol=5.041e-06, Ash=0.01978, Yeast=0.008452,
...     CaO=0.0001446, TriOlein=0.02702, H2SO4=0.001205, Fiber=0.1508,
...     SolubleProtein=0.04805, InsolubleProtein=0.06967,
...     total_flow=32720, units='kg/hr',
... )
>>> dryer = bst.DrumDryer('D610',
...     (feed, 'dryer_air', 'natural_gas'),
...     ('dryed_solids', 'hot_air', 'emissions'),
...     moisture_content=0.10, split=dict(Ethanol=1.0)
... )
>>> dryer.simulate()
>>> dryer.show('cwt100')
DrumDryer: D610
ins...
[0] feed
    phase: 'l', T: 352.33 K, P: 101325 Pa
    flow (%): Water             67.5
              Ethanol           0.000504
              Ash               1.98
              Yeast             0.845
              CaO               0.0145
              TriOlein          2.7
              H2SO4             0.12
              Fiber             15.1
              SolubleProtein    4.8
              InsolubleProtein  6.97
              ----------------  3.27e+04 kg/hr
[1] dryer_air
    phase: 'g', T: 298.15 K, P: 1.01325e+06 Pa
    flow (%): O2  23.3
              N2  76.7
              --  1.33e+06 kg/hr
[2] natural_gas
    phase: 'g', T: 298.15 K, P: 101325 Pa
    flow: 2.45e+03 kg/hr CH4
outs...
[0] dryed_solids
    phase: 'l', T: 343.15 K, P: 101325 Pa
    flow (%): Water             10
              Ash               5.48
              Yeast             2.34
              CaO               0.04
              TriOlein          7.48
              H2SO4             0.334
              Fiber             41.7
              SolubleProtein    13.3
              InsolubleProtein  19.3
              ----------------  1.18e+04 kg/hr
[1] hot_air
    phase: 'g', T: 343.15 K, P: 1.01325e+06 Pa
    flow (%): Water    1.55
              Ethanol  1.23e-05
              O2       22.9
              N2       75.5
              -------  1.35e+06 kg/hr
[2] emissions
    phase: 'g', T: 373.15 K, P: 101325 Pa
    flow (%): Water  45
              CO2    55
              -----  1.22e+04 kg/hr

>>> dryer.results()
Drum dryer                                      Units     D610
Electricity              Power                     kW      845
                         Cost                  USD/hr       66
Natural gas (inlet)      Flow                   kg/hr 2.45e+03
                         Cost                  USD/hr      534
Design                   Evaporation            kg/hr 2.09e+04
                         Volume                       1.05e+03
                         Diameter                   m     3.76
                         Length                             94
                         Peripheral drum area      m2 1.11e+03
Purchase cost            Drum dryer               USD  1.2e+06
Total purchase cost                               USD  1.2e+06
Installed equipment cost                          USD 2.46e+06
Utility cost                                   USD/hr      600

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