Paper 360
In many industrial sectors, odor control is frequently overlooked or considered an afterthought following capital construction projects. Yet, in the pulp and paper industry, there is no mistaking a production plant’s presence in the surrounding community without effective odor abatement measures. Especially in an age when community gathering is easier than at any other time in known human history—due to the quick spread of posts on social media platforms and heightened public expectations of companies—the time before neighborhood odor complaints mount is brief.
The impacts of industrial malodors and subsequent complaints can range in gravity from catalyzing negative community relations all the way up to government-issued mandates to cease operation. Regardless of severity, it is always in plant managers’ best operational, business, and neighborly interests to keep odors at bay and maintain harmony with the local community.
Fig. 1: While conventional odor control methodologies perform well in certain applications, all have shortcomings. Modern plant-based odor removers occupy the sweet spot of safe and effective odor neutralization. ALL FIGURES COURTESY OF ECOSORB.
The issue with odors is particularly complex because they are difficult to quantify, so the success or failure of a mitigation project is typically judged subjectively. In decades past, mills had limited information on malodors and the chemistry that causes them. This could lead to meager masking solutions, such as concealing bad odors with another unsatisfactory coverup in its place. In recent years, however, a few companies have invested significant resources into researching the components that produce these unpleasant olfactory sensations—and into finding ways to determine molecular means of neutralizing the offending constituents.
Effective odor neutralization requires analysis, and accurately determining the offending constituents is challenging. However, pulp and paper manufacturers can enlist the help of suppliers with knowledge and access to advanced laboratory technologies—such as gas chromatographs—to identify the molecular chemistry causing the odors. These supplier experts can then prescribe and provide products specially designed to neutralize unpleasant scents.
CONVENTIONAL SHORTCOMINGS
Off-gas odors in the pulp and paper industry are among the worst of all industrial processes. They often stem from the hydrogen sulfide, mercaptans, and sulfur dioxide created during the process. In kraft pulping, for example, heat and chemicals are applied to pulp wood chips for making paper. This reaction produces gaseous sulfur compounds called total reduced sulfur gas, which is often likened to the smell of rotten cabbage or rotten eggs. These odors can be offensive at best, or harmful at worst, to mill workers and the public.
In addition to kraft pulp mills, other operations—such as wastewater treatment, OCC pulp mills, and landfills—can all generate unpleasant odors. Each of these is distinct, and all too frequently, odor control methodologies that work in one application do not in another.
While there are many odor control methodologies available, conventional solutions each have shortcomings. These methods include masking agents, chemical scrubbers, adsorption and carbon filters, ozone, biological filters, and others (Fig. 1).
Each of these conventional methods falls short of ideal. It may be hazardous, ineffective on organic or inorganic odors, unsuccessful at neutralizing odors, or a combination of all these issues. Additionally, many of these strategies require expensive equipment, materials, setup, and maintenance from multiple vendors, rendering systems unwieldy and costly to operate.
In contrast, modern, plant-based odor removers require relatively little equipment to deploy. They safely span all odor removal applications by using research-based formulations, each specific to the odor being targeted for removal.
STANDARDIZATION PROVIDES BENEFITS
Leading plant-based odor control solution suppliers use advanced technology and their expertise to develop standardized formulations. These formulations are meticulously crafted to address a wide range of odor concerns within specific industries—for example, covering a variety of odors from different processes used in the pulp and paper industry. These standardized blends are rigorously tested, ensuring their effectiveness in a multitude of plant settings and providing:
- Reduced lead time: Standardized formulations are readily available “off-the-shelf,” minimizing wait times after order placement.
- Faster implementation: Turnkey solutions minimize startup and commissioning time, helping implementations to get off the ground more quickly.
- Proven efficacy: The successful use of standardized formulations across diverse applications instills confidence within the industry.
- Adaptability to process variations: These blends provide the flexibility to accommodate variance in a facility’s product and processes without needing to change the formulations used.
- Reliable supplier support: Readily available standardized solutions help ensure continued support from expert suppliers.
CUSTOM FORMULATIONS FOR UNIQUE NEEDS
While standardized solutions address most needs in the industry, some specialty processes may require a customized approach. In these cases, expert suppliers can tailor solutions to the specific odor profile present.
The first step is collecting air samples from the facility, using advanced Markes thermal desorption tubes to store the samples for up to weeks at a time. This ensures high accuracy analysis, even at low concentrations. This is an improvement over traditional sample collection methods, which last only hours and quickly degrade.
These samples are then analyzed in the lab using gas chromatography-mass spectrometry (GC-MS) to identify the precise molecular makeup of odorous compounds (Fig. 2). The GC-MS produces a chromatogram (Fig. 3), which is a visual representation of the detected substances and their relative concentration.
Each compound detected appears as a single peak on the graph, with the corresponding retention time value used for identification. Once the odor-causing compounds are identified, scientists create a formulation using plant oils to molecularly neutralize the odors when applied in the air.
By offering both standardized and custom solutions, plant-based odor control providers cater to a wide range of needs within the pulp and paper industry and beyond. Dispersal of these agents is conducted via atomization or vaporization, depending on the application.
ATOMIZATION AND VAPORIZATION
Through atomization, concentrated odor eliminators are mixed with water and pumped through pipes to affected areas. Droplets are sprayed into the air, neutralizing odor molecules on contact. Atomization nozzle systems provide a significant level of control, with the ability to vary product volume, surface area, and spray method (Fig. 4).
Atomization can occur via hydraulic high-pressure or pneumatic low-pressure systems. High-pressure systems treat odors by dispersing a fine mist into the air to treat escaping gas emissions and surface odors, while low-pressure fan systems are effective in confined spaces and environments for containing multiple odors released in a small area.
Low-pressure fan delivery systems spray a mixture of odor eliminator and water through the fan’s jet stream, creating a fine mist in the area of application. Because these systems are generally compact, they are flexible and customizable, and they are easily transitioned from one process area to another. Additionally, the use of concentrated odor eliminators eases shipping and storage because water, which makes up most of the bulk and weight, is added at the site.
Unlike atomization, no additional water is added in vaporization systems, which pump undiluted odor eliminators through perforated pipe distribution systems, creating a dry vapor to neutralize airborne odors. Vaporization uses less water compared to atomization, providing cost savings and a more eco-friendly delivery method, but it can only be used in less humid locations.
Vapor phase systems deliver dry odor eliminator at rates as low as 130 cubic feet per minute (CFM) to as high as 2,400 CFM, making them adaptable to many locations and applications. These flexible and efficient delivery systems:
- Provide smaller droplets and higher absorption for better odor control.
- Require no additional water to operate.
- Eliminate the need for mixing and diluting.
- Reduce maintenance requirements because no nozzles are required.
CASE STUDY: MILL CUTS COMPLAINTS
A prominent US pulp and paper producer relied on air scrubbing to treat the air leaving its facility. However, a growing chorus of odor complaints from nearby homes and businesses showcased the ineffectiveness of these efforts, threatening the mill’s continued production. When local authorities eventually issued an order to significantly curb off-gassing or cease operations, mill management knew it needed to find a better solution.
In conjunction with scientists at Ecosorb, a natural odor control solution supplier, the team collected air samples from around the plant to study the odor profile and offending compounds. Ecosorb’s 806 blend, which is specifically designed for the unique odor challenges of paper mills, was identified as a match to effectively counteract and neutralize the offensive odor-causing compounds in the air.
The site dispersed the product without the need to add water or any other substance (Fig. 5), using low-maintenance vaporization systems. This effectively combatted odors from various sources around the facility, including ponds and basins, sludge press dewatering, OCC recycle storage, kraft pulping operations, cooling towers, and exhaust stacks (Fig. 6).
Consisting of plant-based ingredients, the product is environmentally friendly and safe to handle without a measurable flash point, and it provided the following benefits for the producer:
- Absorbed, reacted with, and molecularly neutralized odors without masking.
- Did not require any permits.
- Continued safe operations with low maintenance constraints for plant personnel.
The solution effectively treated facility odors, significantly reduced complaints, and removed the threat of a regulatory-mandated shutdown. It also improved the producer’s relationship with the surrounding community.
ECO-PRODUCTS EMPOWER BUSINESS GROWTH
By applying plant-based odor removers in and around pulp and paper facilities, processors can effectively mitigate foul odors using methods that are safe, environmentally friendly, and cost-efficient. These formulations do not mask smells, but instead neutralize them by breaking down and nullifying odor-causing molecules.
Simpler to operate and maintain than conventional odor control methodologies, the dispersion of renewable and biobased ingredients via atomization and vaporization systems allows processors to produce at high volumes without sacrificing their reputations. This helps businesses maintain a positive rapport with their neighbors, and it empowers them to focus on profits and production, instead of addressing odor complaints.
