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 (Stream], optional) –

    • [0] Wet solids.

    • [1] Dry gas.

    • [2] Natural gas.

  • outs (Stream], optional) –

    • [0] Dried solids

    • [1] Hot gas

    • [2] Emissions

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

  • R (float, optional) – Flow of hot gas over evaporation. Defaults to 1.4 wt gas / wt evap.

  • 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 varied to meet the R specification (i.e. flow of hot gas over flow rate 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
    composition (%): 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
    composition (%): O2  29.1
                     N2  70.9
                     --  3.22e+04 kg/hr
[2] natural_gas
    phase: 'g', T: 298.15 K, P: 101325 Pa
    composition (%): CH4  100
                     ---  1.11e+03 kg/hr
outs...
[0] dryed_solids
    phase: 'l', T: 343.15 K, P: 101325 Pa
    composition (%): 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
    composition (%): Water    39.4
                     Ethanol  0.000311
                     O2       17.6
                     N2       43
                     -------  5.31e+04 kg/hr
[2] emissions
    phase: 'g', T: 373.15 K, P: 101325 Pa
    composition (%): Water  45
                     CO2    55
                     -----  5.56e+03 kg/hr

>>> dryer.results()
Drum dryer                                 Units     D610
Electricity         Power                     kW      845
                    Cost                  USD/hr       66
Natural gas (inlet) Flow                   kg/hr 1.11e+03
                    Cost                  USD/hr      243
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
Utility cost                              USD/hr      309

References