Responding to this need for precise humidity control are manufacturers who are continually improving their dehumidification equipment for these demanding applications. In general, newer dehumidification equipment is becoming less expensive, more energy efficient, and smaller, while incorporating more sophisticated controls that can hold a space within a couple of percentage points of design condition.

It would be impossible to highlight every type of new dehumidification equipment currently being offered, but what follows are several manufacturers' more recent innovations that work well in pharmaceutical applications.

Dectron’s Dry-O-Tron combines precision environmental control with high-efficiency gas and particulate filtration.

Dectron Incorporates Gas Filters

"Through our Circul-Aire division we can also incorporate gas filters if the outdoor air at the particular facility is deemed unacceptable for the process manufacturing," noted Brian Monk, P.E., vice president of sales/marketing for Circul-Aire (Dectron Internationale).

The Dry-O-Tron was recently installed in a facility that produces Vitamin C tablets. This particular product can create large amounts of dust and also reacts poorly to high levels of humidity. The Dectron system provided tightly controlled humidity while removing a significant amount of moisture from the outdoor air. Since the facility was in an industrial zone, the outdoor air quality was questionable at best. The Dectron system incorporated two stages of gas filters (activated carbon and potassium impregnated alumina) and three stages of particulate filtration, up to 99.97% at 0.3 micron.

Monk said that the Dry-O-Tron gives the designer the ability to incorporate all aspects of air treatment into one system. "Humidity, temperature, gas, and particle filtration can all be packaged in one system that is integrated into the building or process DDC system. Moreover, in areas of high latent/sensible outdoor air, significant moisture can be removed before entering the process space so that stability of temperature, humidity, and pressurization can be maintained."

Des Champs’ newest Desi-Wringer has better regeneration heater design and more sophisticated digital controls.

Des Champs Simplifies Jobs

The equipment has evolved over the years, and its latest iteration is smaller and includes more sophisticated controls and more pieces of the total system (into complete integrated systems). "The newer Desi-Wringer has better regeneration heater design and more sophisticated digital controls," said John Bergman, marketing consultant to Des Champs Technologies. "We now incorporate a number of test ports for system troubleshooting, and we use chain-drive rotors and Viton seals, which require less maintenance than previous designs."

A recent pharmaceutical application of the Desi-Wringer involved a facility in which the manufacturer intended to do research on pill manufacturing. The company wanted the equipment to be a single piece instead of a built-up system. Des Champs was able to provide a unit that consisted of pre-cooling with integral mechanical refrigeration; 30% and 95% filtration; direct-fired gas regeneration; post-cooling with integral mechanical refrigeration; indirect gas process heating; and 99.97% HEPA final filters. The process fan was controlled by a VFD and was modulated to duct static pressure, while controls were furnished to integrate into the company's BAS.

Bergman noted that the new Desi-Wringer simplifies the design engineer's job, because of the single-source responsibility by one manufacturer. "Formerly it was necessary to engineer and select virtually every single component of a system - a very complex and risky operation, if you don't do this sort of work every day, and few do."

DryKor’s Universal Dry Top is self-controlled by a PLC controller that is mounted within the unit control panel. The industrial units can also be remotely controlled by a BAS.

DryKor Disinfects Air

Yigal Lazarov, Drykor's regional marketing manager for Europe, the Indian Sub-Continent, and Australia, stated that the company's unique technology and products provide energy-efficient humidity control and have a high capacity of moisture removal. In addition, the equipment treats, filters, and disinfects the air.

"In our dehumidification process, approximately 94% of the bacteria and airborne micro-organisms are eliminated. Since the humidity is absorbed and discharged by the salt solution, we do not condense the humidity, therefore we do not create either a ‘wet coil' or ‘condensate water puddles,' which are breeding grounds for bacteria growth," noted Lazarov.

A large pharmaceutical company recently installed several Universal DryTop units because of their energy-efficient nature. The equipment uses lithium chlorite (LiCl) as liquid desiccant, which is passed over specially designed honeycomb-structured PVC fills to form a thin film. Air that needs to be treated is passed over the film, and the LiCl absorbs the moisture in the air. The LiCl becomes diluted with time, due to the absorption of moisture from the air, and it is then regenerated using the refrigeration system, which saves energy.

Lazarov stated that engineers should like the equipment, because it can reduce the amount of cooling, especially in new construction. "The most efficient system is a combination of DryKor's dehumidifier that will efficiently treat the latent load plus a smaller cooling unit to treat the sensible load. For retrofit or add-on situations, the equipment can solve the problem of moisture removal when the existing system cannot handle the latent load. The simple addition of the DryKor units to the local cooling unit eliminates the need to enlarge the entire cooling system."

Munters’ ICA equipment can typically be used in any manufacturing process that requires less than 50% rh, which can include the manufacture of gelatin, gel caps, effervescents, and tablets.

Munters Customizes Air Handlers

Jeff Siemasko, business development manager for Munters Corporation, said that the main difference between the ICA and other products Munters manufactures is the custom air handler box construction. The ICA incorporates two important features that are necessary for custom air handlers in the pharmaceutical industry: They are double wall and have no through-metal construction.

"All air handlers need to be insulated, and this insulation cannot be exposed to the air it is processing. This is accomplished by placing the insulation between the inner and outer skins of the unit. The double-wall construction is also important, because it allows the customer to clean the system when required," stated Siemasko.

The "no through-metal construction" means the exterior skin does not come in contact with the interior skin, preventing what is referred to as a thermal bridge. The air in these systems is often cooled and without a thermal break, the exterior of the system could become cold. This can result in condensation on the outside of the unit, which is not acceptable.

"Our equipment is typically used in any manufacturing process that requires less than 50% relative humidity," said Siemasko. "Some typical applications including manufacturing of gelatin, gel caps, effervescents, and tabletting. Dehumidification systems are also often used for fluid beds and pan coaters."

Stulz Air Technology Systems, Inc.’s units incorporate more energy-efficient motors and desiccant materials.

Stulz Offers Flexibility

The DHP Series is a modular system that can be readily adapted to many different configurations based on the individual requirements of the specific application. "This significantly reduces manufacturing lead times, provides more option availability, and reduces manufacturing costs. The majority of the components are pre-engineered so we can provide a quality custom air handler unit at a much lower cost than those normally associated with a custom designed unit," said Mia DiClaudio, marketing coordinator for SATS.

A DHP unit was recently installed at a facility that had three different processes, each of which took place at a different time. One process was a coating application for tablet coating, which required a set condition; another process involved gel tablets, which needed a different setpoint; and the final application maintained the storage environment for the raw materials.

"This company selected our product, because we could integrate the technology and components into equipment that was multi functional and readily adaptable to maintain the three different conditions. Normally each process would require a separate piece of equipment, but our configuration required minimal effort and resources," noted DiClaudio.

DiClaudio added that because the DHP was designed to incorporate many environmental control components in one unit, the design engineer will have greater flexibility. "Engineers can utilize just one system to meet the total environmental control aspects of their projects. It becomes a single-source provider, which reduces overall equipment cost and installation cost on a given project." ES