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For the regeneration of a liquid desiccant, a stripping agent is
used which is liquid at ambient temperature and pressure, and forms
a heteroazeotrope with water, along with the following steps: (a)
distillation of the water-laden liquid desiccant to form vapor and
partially regenerated liquid desiccant; (b) reboil partially regenerated
liquid desiccant; (c) stripping of partially regenerated liquid
desiccant during (a) and (b), using vaporized stripping agent; (d)
a condensing of vapor the exiting the distillation, the condensation
producing two liquid phases, one mainly water and the other mainly
stripping agent; (e) heating the stripping agent-rich liquid phase
exiting step (d) to generate a vapor phase which is richer in water
than said liquid phase and a water-depleted liquid phase; and (f)
returning the vaporized liquid phase exiting step (e) to step (c).
Desiccant-coated substrates, regeneratable rotary dehumidification
wheels and other devices for gas (e.g., air) treatment using those
substrates, and processes for making them are disclosed. The substrates
may have coatings in thicknesses of from about 2 to about 10 mils
containing particles of one or more adsorbent desiccants and an
organic water-based binder. The desiccant particles retain a high
fraction of their original adsorption capacity because the pores
of the desiccant particles contain a pore-clearing agent prior to
the binder setting and the pore-clearing agent leaves the pores
during the manufacturing process to prevent the binder from blocking
the pores. In preferred embodiments a mixture of different desiccants
is used and a particle suspending agent keeps the particles well-mixed
so that the desiccant particles in the coated substrate will be
as well-mixed as possible. The suspending agent may also function
as the pore-clearing agent. A pH-adjusting agent may be used to
control the pH of the coating if the binder or another constituent
of the coating is pH-sensitive.
The invention resides in a process air dryer system for plastics
processing machines and method for drying process air comprising
two desiccant towers repeatedly alternating between process and
regeneration cycles. In addition to conventional bottom heaters,
each tower has an additional generally central heater so as to reduce
the time required to regenerate saturated desiccant. When a tower
is undergoing regeneration of its desiccant, generally centrally
heaters aid conventional bottom heaters in drying saturated desiccant
so as to reduce conventional regeneration cycle time by as much
as 25% to 30%.
An energy-efficient space conditioning system comprising an integrated
direct expansion heat pump with desiccant and thermal exchange wheels.
A method is disclosed for controlling the system to have four distinct
modes of operation: Heating, Cooling/Regneration, Coil Defrost,
and Regeneration.
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