A Cost- and Environmentally Effective Approach to Supplying Nitrogen Gas to Pharmaceutical Manufacturing Industrial Facilities - Pharmaceutical Technology

Latest Issue

Latest Issue
PharmTech Europe

A Cost- and Environmentally Effective Approach to Supplying Nitrogen Gas to Pharmaceutical Manufacturing Industrial Facilities
The authors argue that the cost of generating nitrogen via an in-house gas generator is considerably lower than the cost of using fractional distillation to generate liquid nitrogen.

Pharmaceutical Technology
Volume 34, Issue 7

Customization of pressure-swing adsorbtion systems

An in-house industrial-scale PSA system can be precisely customized to meet the specific needs of an application. As an example, systems provided by Parker Hannifin's Filtration and Separation Division (Baltimore, MD) include a number of features to ensure that the optimum system is provided (see Figure 2). These features are described below.

An energy-efficient control system. If the demand for nitrogen decreases, the time for the production cycle increases. This leads to a longer period between desorption steps, which reduces the amount of energy required to compress the feed stream. An additional benefit is that the seat life of the process valves is extended as they are not cycling as frequently.

Differential pressure-bed monitoring. High-bed differential pressure-bed monitoring protects the beds from excessive differential pressure during feed and equalization pressurization.

Optimal bed-size ratio. The length-to-diameter ratio of each bed is sized to provide superb performance. This prevents feed-gas channeling, which leads to an inefficient separation.

Flanged bed covers. The CMS bed is accessed via an ASMEflanged cover to allow for rapid reloading of the vessels (some systems use welded covers). The use of a flanged cover for the chamber makes it easier to access the PSA bed as the cover can simply be lifted by an operator. If, however, the cover is welded on, it is necessary to undo the weld and then reweld it in position.

Advanced valve design. A valve leak-check system is incorporated in the valve to determine valve-seat health without having to remove the valves from the system. The valve leak check can be performed in less than 10 min.

Standby mode. If nitrogen is no longer needed (e.g. the storage tank is full) the system will automatically shut down and turn off the compressor, saving power and reducing wear and tear on the system. Once the system determines a need for the generation of additional nitrogen, it will automatically start back up and seamlessly resume nitrogen production.

Routine operation of a dual-bed nitrogen-generation system

A dual-bed nitrogen-generation system can operate on a 24-hour, 7-day basis with a minimum of user interaction. Once the operational parameters are established, the system automatically responds to changes in the nitrogen demand to minimize power consumption and valve usage.

Required maintenance of an in-house nitrogen generation system

A significant benefit of an in-house PSA system is that an extremely low amount of maintenance is required. System maintenance involves periodic checking and replacement of filter cartridges (if necessary), checking and repacking the valves, and changing the oxygen analyzer fuel cell. In normal operation, the system's filter cartridges are checked every three months and replaced every six months. The valves are checked every six months and rebuilt with new O rings annually. The oxygen analyzer fuel cell should be replaced every year.

Economic benefits of nitrogen generation via PSA technology

Although the base cost of nitrogen generated via fractional distillation may be quite low, the overall cost of supplying the requisite gas to a pharmaceutical manufacturing facility may be significantly higher due to transportation issues. As an example of this point, the relative cost for bulk liquid nitrogen on an island such as Puerto Rico (which has a very limited local supply of bulk liquid nitrogen) is significantly higher than in an industrialized, metropolitan area such as New Jersey. In addition to the transportation costs, the end-user of nitrogen generated via fractional distillation must include a broad range of additional costs such as the acquisition and maintenance of the storage facility, pipes to get the gas to the final location from an external storage tank, loss of nitrogen due to venting of the storage tank, as well as the paperwork and time required for purchasing activities. In contrast, the running cost of a PSA nitrogen generator is quite lower because electricity for the compressor and replacement parts is all that is required.

The return on investment that can be expected from a PSA system for the generation of nitrogen is dependent on a variety of factors and is typically less than two years; in some cases the system pays for itself in a year or less. In a typical facility, the cost to generate nitrogen via a PSA generator is less than $0.15 per hundred cubic feet (CCF). This includes annual maintenance costs, replacement parts and electricity. In comparison, the average cost of liquid nitrogen in areas where it is not readily available, or if the facility is captive to a single supplier, can range up to $1 per CCF.

An additional economic benefit of the use of an on-site system for the generation of nitrogen is the fact that the user is assured that the gas will be available when required. In contrast, obtaining nitrogen from an external source involves the risk that it may not be received when required due to problems at the external source or transportation difficulties, which could lead to a costly manufacturing delay.


blog comments powered by Disqus
LCGC E-mail Newsletters

Subscribe: Click to learn more about the newsletter
| Weekly
| Monthly
| Weekly

What role should the US government play in the current Ebola outbreak?
Finance development of drugs to treat/prevent disease.
Oversee medical treatment of patients in the US.
Provide treatment for patients globally.
All of the above.
No government involvement in patient treatment or drug development.
Finance development of drugs to treat/prevent disease.
Oversee medical treatment of patients in the US.
Provide treatment for patients globally.
All of the above.
No government involvement in patient treatment or drug development.
Jim Miller Outsourcing Outlook Jim MillerOutside Looking In
Cynthia Challener, PhD Ingredients Insider Cynthia ChallenerAdvances in Large-Scale Heterocyclic Synthesis
Jill Wechsler Regulatory Watch Jill Wechsler New Era for Generic Drugs
Sean Milmo European Regulatory WatchSean MilmoTackling Drug Shortages
New Congress to Tackle Health Reform, Biomedical Innovation, Tax Policy
Combination Products Challenge Biopharma Manufacturers
Seven Steps to Solving Tabletting and Tooling ProblemsStep 1: Clean
Legislators Urge Added Incentives for Ebola Drug Development
FDA Reorganization to Promote Drug Quality
Source: Pharmaceutical Technology,
Click here