Baton Rouge-based sulfuric acid plant maintenance company designs one-of-a-kind scrubber that captures NOx emissions Nitrous oxide. Niter. NOx Those familiar with the day-to-day operations and maintenance of the sulfuric acid industry know all too well how these dangerous and heavily regulated emissions can equal to downtime and decreased productivity. In California for example, several sulfuric acid plants have been rendered useless for fear, in part, of releasing NOx into the atmosphere. However, downtime is not the only issue of concern in larger doses, NOx emissions can lead to air pollution, illness and possible death. But as a byproduct of any sulfuric acid plant operation, NOx is in the truest sense of the word a necessary evil. Settling in sulfuric acid plant mist eliminators (as well as sludges throughout the wet side of an acid plant), NOx emissions in years past have primarily been the result of “dipping” the mist eliminator candles in a scrubbing solution for cleaning. Easily identifiable, a NOx gas release appears in the form of a large, orange/yellow plume of vapor. But VIP International Vice President Hoss Maddry explained watching that orange plume rise into the atmosphere is now an image of the past and not only because of regulation.

We’ve developed a portable scrubber system that solves a problem which has plagued the sulfuric acid industry for years,” Maddry said. “Our process removes the oxygen molecules from NOx, releasing only harmless nitrogen into the atmosphere. From there, either VIP or the plant itself can neutralize the solution for proper disposal.”

Measuring 6 feet in diameter and standing 22 feet tall, the “no-NOx” scrubber incorporates a 22,000-cubic-feet-per-minute blower designed to capture even the smallest traces of NOx. There’s never been a way to capture NOx emissions, so instead of cleaning expensive elements, some plants were removing and disposing of them, or, worse yet, not doing anything at all and letting their plant site idle,” Maddry continued. “Now, the problem can be handled correctly.”

An Attractive Alternative

Even those not entirely familiar with the sulfuric acid industry can see the advantages of a scrubber system that captures NOx emissions. These range from simple economics to having the peace of mind that comes with knowing potentially harmful emissions are being contained. However, sulfuric acid plant operators in particular will find the VIP scrubber system most attractive by providing a cost-effective alternative to the cleaning and disposing of contaminated sulfates. “We’ve eliminated a lot of worries associated with cleaning mist eliminators and sludges that have built up over time,” VIP International President and CEO Jack Harris offered. “In the past, it was easy to side-step the issue because there was no simple solution to the problem. But now there is an economical solution that is an integral part of the day-to-day services VIP performs.” Harris explained costs are also curtailed by cleaning the mist eliminator elements to maximize the true life potential of the candles or pads.

“By capturing the NOx, plants can legally clean and reuse their elements rather than spending thousands of dollars on new ones every time they find sulfate buildup,” he explained. “This alone will reduce their maintenance costs significantly.” In addition, the scrubber eliminates the need for washing the plant’s towers with a chemical solution (which reduces NOx emissions but also wears down the overall life of the plant) and eliminates the necessary work stoppage due to those working near the cleaning of the candles.

“Our scrubber system is unique in that it can be utilized in conjunction with equipment already being used as part of an existing plant wide turnaround,” Harris said. “It only takes a few hours to set up and doesn’t alter the schedule of any work being performed in the area of the scrubber. The capture of the NOx plume totally alleviates the need for moving or shutting down work in the plant’s surrounding area.”

Maddry agrees the addition of the no-NOx scrubber was a natural evolution of VIP’s existing line of services, having established itself for years as a leader in sulfuric-acid-plant maintenance. “As a whole, I think it definitely takes our commitment to industry one step further,” he said. “If we’re already inside a facility cleaning elements, for example, we can just as easily neutralize these contaminated sulfates by adding the scrubber to the tail-end of equipment that has already been set up.” But perhaps the most attractive aspects of VIP’s scrubber are the environmental and regulatory ramifications.

No NOx is good NOx

Darwin Passman, former Dow Chemical supervisor whose experience includes research and development of co-gasification processes (including NOx and sulfur species emissions), explained the consequences of unbridled NOx emissions.

“NOx represents two separate problems,” he explained. “One is pollution of the environment and the other is personnel exposure. Environmentally, NOx is a primary factor that increases the lower ozone layer we know as smog. Ozone (O3 ) is formed when sunlight decomposes NOx to nitric oxide (NO) and atomic oxygen (O). The oxygen atom combines with the natural (O2 ) oxygen molecule to form Ozone (O3 ). The smog formed is toxic to people and the environment. It’s considered the primary cause of the greenhouse effect.”

“From a personnel standpoint NOx is regulated by OSHA using the National Institute for Occupational Safety and Health (NIOSH), OSHA’s research division. NIOSH performs research and gathers data to determine recommended threshold limit values (TLVs), as well as their IDLH (immediately dangerous to life and health) exposure limits. The IDLH for NO2 is 20 parts per million. The short term over exposure to NOx can have acute health effects.”

According to Passman, NOx is regulated by the DEQ and EPA, which in some cases permits a set number of pounds of NOx to be released per day. Any releases over the permitted allowance must be reported to the appropriate agency according to its set guidelines.

The Right Idea for the Right Time

Experts in the sulfuric acid industry agree that this is an idea whose time has definitely arrived. Sulfuric acid Consultant Bob Jones, for example, foresees immediate impact on heavily regulated regions such as the West Coast.

“In California, there’s a lot of acid work that can’t be done because of strict emissions laws,” Jones explained. “I think when the word gets out, these plants will find a scrubber system like this will solve a lot of their troubles.

Jones also predicts that where the West Coast goes, the rest of the country eventually follows.

“I think as time goes by, the rest of the states will eventually adopt stricter emissions regulations of their own,” he offered. “Louisiana has passed some strict NOx laws in the past several years, with other Gulf South states following suit.”

“This trend has become evident in the fertilizer industry, for example. For years, the chemical plants were the only ones being heavily regulated, but now the fertilizer industry is seeing more regulations heading its way.”

“The bottom line is that now there’s a way to efficiently and legally capture these emissions in a manner that wasn’t available before,” Maddry summarized. “For years, industry has either ignored the problem on one end of the spectrum, or shut down its plants for fear of polluting the atmosphere. Now, there’s an easy solution to both problems.”