The market for pneumatic conveying systems in the United States will rise from $4.5 billion this year to $6 billion in 2022, predicts “Pneumatic Conveying System Market Analysis…,” a report issued in September 2015 by Grand View Research, San Francisco. A combination of factors, including demand for improved process hygiene, reduced end-product contamination, worker health and safety issues, and advances in technology that integrate compact pressure-vessel technology with intelligent control, are driving the growth, note the report’s authors. The ability to further increase productivity, improve product quality and boost cost savings also may further fuel demand significantly, they add.
The experiences of vendors such as Nol-Tec Systems, Hapman and Gericke — together with their customers — illustrate how these various demands are playing out in the plant.
One of the game changers now is automation, says Mike Weyandt, corporate sales manager, Nol-Tec Systems, Lino Lakes, Minn. He cites a plant that invested in servo motors, pressure transducers and more, all of which could be accessed from the control room. “This customer had experienced upsets in his automation process caused by improper adjustment of the valves on a manually adjusted system. This resulted in quality control issues, excessive use of conveying air, system plugging and downtime. By spending the money to make the system ‘smart,’ he reduced long-term costs by eliminating these problems. He was thinking big picture, long term.”
In addition, the growing affordability of technologies such as variable frequency drives, inverter motors and pressure transducers will increase their use in pneumatic conveying technologies demanded by chemical companies, he believes.
Identifying the best technology for the particular application is key to achieving benefits, stresses Weyandt. “When we are contacted by a customer, our first question is always about the material in question and its physical characteristics. Then we move on to the environment within the plant, i.e., whereabouts the conveying equipment is to be located.”
From here, the first decision is determining if dilute-phase or dense-phase conveying is best for the material. Then, the company considers the choice among vacuum, positive pressure differential or negative pressure differential operation. Vacuum often is preferred if a material is toxic or explosive.
Complexity of installation is another consideration. “If it is just a pipe going straight up and a little bit of horizontal, a bucket elevator or belt conveyor might be more appropriate. However, if there are lots of turns involved, the system rapidly becomes more difficult to service. Here, pneumatic would be better because the system is mostly comprised of pipe which can usually be supported from the structural members which are holding up the roof or walls of the building,” he says.
Ease and cost of maintenance are important issues, too, Weyandt notes. Users of mechanical systems usually are very aware of the maintenance costs involved with all their assorted shafts and bearings, he believes. “Our experience has shown that the maintenance costs of a pneumatic conveying system are substantially less than a comparable mechanical system.”
Pneumatic systems also are easier to keep clean than mechanical ones, he notes. So, they are gaining growing use where this is a crucial need, for example, in pharmaceutical and fine chemical manufacturing.
In general, whenever a customer has a dry chemical powder and is concerned with degradation, dense phase is the best option, says Weyandt. He cites the experience of a manufacturer needing to pelletize virgin carbon-black powder, both for hygiene reasons and mixing effectiveness. It switched to dense-phase conveying because the lower transfer velocity minimized product degradation. Avoiding product degradation also was the driver for a terephthalic acid manufacturer to replace a dilute-phase system with a dense-phase one, he notes.
However, if separation and breakage aren’t issues with a material, then 99 times out of a 100, dilute phase is chosen, Weyandt says. “Dilute phase is much more commonly used and is much better researched because its principles of operation are very simple.”
For its part, Hapman, Kalamazoo, Mich., has identified what it calls the six main materials-handling challenges in the chemical industry.
“At Hapman, the focus is on offering technologies that can overcome the chemical industry’s major materials-handling challenges, notably dusting, segregation, degradation, batching inefficiencies, precision and flow issues, and cleaning and sanitation problems,” notes director of marketing Chris Gibbs.
As a consequence, vacuum conveying systems are at the forefront of its recent project installations. One is for Werner G. Smith (WGS), Cleveland, which manufactures fatty oils and synthetic esters and also processes vegetable and fish oils, blown oils and non-ionic emulsifiers.