Opportunities for lignin valorization: an exploratory process
© The Author(s). 2017
Received: 14 December 2016
Accepted: 3 August 2017
Published: 28 August 2017
For decades, the pulp industry has struggled to create sustainable value-added opportunities for lignin, and the issue is now at the forefront of second-generation biorefinery research and development efforts. Our work presents a sequential process for examining potential lignin valorization. The chemical and physical properties of lignin cause issues in isolation, characterization, and standardization and, therefore, product manufacturing. First, a short list of high-opportunity lignin products was developed from the literature. Several low-hanging product opportunities were identified, from which, lignin-based powdered activated carbon (PAC) for the sequestration of mercury from power plant flue gas was selected for further examination due, in part, to lignin’s similarity to lignite coal. Next, an analysis of the web-based written content of PAC suppliers’ promotional materials was performed to assess the attributes on which PAC products are sold and purchased. Finally, potential electric generating power plant buyers/users of lignin-based PAC for mercury sequestration were surveyed to examine the importance of 16 PAC product and service attributes, identify potential entry barriers for a new PAC product, and assess the market opportunity for lignin-based PAC.
This research deployed a multi-phase market analysis based process including: a PAC vendor content analysis; and survey techniques. Phase I analyzed web-based content of PAC vendors’ promotional marketing literature tailored to power plant buyers/users for their PAC products. Phase II incorporated the Phase I results into an exploratory e-survey of select PAC buyers/users in the U.S. power generation industry. Combining these methods provides an exploratory market perspective on lignin valorization.
The top three product and service attributes for buyers/users of PAC for mercury mitigation were Product Reliability, Product Effectiveness, and Proven Product Performance; the top three barriers to entry for a new lignin-based PAC include Title V Permitting, Operational Impacts, and Compliance with Regulations. Buyers/users are undecided about trial testing a lignin-based PAC product.
This paper provides a logical and systematic process for exploring new product opportunities in business-to-business markets and provides insights into the market potential for lignin-based PAC for mitigating mercury emissions from US electric generating power plants.
The corn-grain ethanol industry accounts for nearly 10% of gasoline consumption in the US transportation sector . However, public pressure on food vs. fuel and the 10% maximum ethanol blend wall are moving biofuel investment toward next generation lignocellulosic biofuels . These second generation biofuels first separate the carbohydrate fraction (cellulose and hemicellulose) from lignin waste and then convert the fermented sugars into fuels [2–5]. Lignin constitutes 15 to 40% dry weight of lignocellulosic feedstock resulting in a large waste stream . Lignin, an established byproduct of pulp mills, has traditionally been burned for combined heat and power. However, in second generation biorefineries, approximately 60% more lignin is generated than what is needed to meet plant energy needs through combustion [6, 7]. As a result, research efforts are accelerating to identify viable opportunities for lignin valorization.
In 1927, Marathon Corporation began efforts to commercialize lignosulphonate products, but outlets did not begin coming to fruition until 1948 [8, 9]. The pulp industry, currently the world’s largest producer of lignin, has benefited little from value-added lignin products despite advances in lignin valorization research . Conversion of lignin into commercial chemicals, materials, and fuels is costly due to physical and chemical properties, including its heterogeneous structure, impurity from isolation, and unique reactivity [4, 6, 10–14].
Multi-phase process for new lignin product-market opportunity research
Value-added applications for biorefinery waste lignin
PAC vendor content analysis
PAC buyer/user survey
Assess the criteria in which PAC is currently promoted by vendors
Explore attributes in which lignin-based PAC for mercury sequestration from electric generation power plant flue gas is purchased, examine barriers to entry and market opportunity
• The process may be applied to investigate other value-added opportunities.
• Lignin has a potential market application as PAC for mercury sequestration from electric generating power plant flue gas.
Lignin was discovered in 1838 by Anselme Payen when wood reacted in an acidic then alkaline solution, resulted in an insoluble residue . Since then, over 10,000 scientific papers have been published on lignin, each contributing to a puzzle that remains incomplete today .
In the plant, lignin has major processes necessary for plant life, by providing structure, energy storage, mechanical and biochemical stress protection, antioxidant protection, and water transportation . Lignin’s basic chemical structure is comprised of three separate molecules: conifery alcohol, sinapyl alcohol, and p-courmaryl alcohol (Chen, 2005). The molecules tend to bond to one another in random formations within lignin, making the molecule heterogeneous in nature, difficult to isolate, characterize, and standardize, which affects researchers’ ability to formulate lignin into chemically reproducible products. Leading researchers have sought applications where the heterogeneous structure has had little effect on the reproducibility and consistency of a lignin-based product (I. Dallmeyer, personal communication, October 15, 2015; [17–20]).
Markets for potential lignin-based products vary in terms of volume and value, creating different strategic opportunities for biorefineries to add value to lignin (Fig. 1). Whereas lignin-based phenol and carbon fiber are poised to capture the largest market potential, factors such as cost of production and viable chemical pathways to products limit commercial feasibility [4, 29].
An alternative potential market with lower volume and value potential is lignin-based benzene, toluene and xylene (BTX), which requires a depolymerization of lignin followed by separation, of which there are technology limitations [12, 30]. As shown, lignin’s valorization can be separated into several greater categories of value-added applications, feedstock for energy production, a raw material in low-volume, high-value chemicals, a raw material in high volume, low value chemicals, and as a “precursor for material applications” . Powdered activated carbon (PAC) is another potential market due to lignin’s high carbon content, abundant supply, and the changing regulatory landscape for electric generating power plants [17, 32–34].
Under a US Department of Agriculture grant, the Northwest Advanced Renewables Alliance (NARA) of public universities, government laboratories, and private industry is attempting to stand up an economically viable supply chain from woody biomass to a variety of biorefinery value stream outputs (www.nararenewables.org). The valorization of biorefinery lignin has received much attention by NARA researchers and is viewed as a critical value-added component of the project’s technical economic analysis . One of the opportunities identified by the NARA interdisciplinary teams to add value to waste lignin is the development of an emission-absorbent PAC product. The PAC market opportunity attractiveness has been greatly enhanced by recent US regulations to mitigate mercury emissions from power plant flue gas . The market for PAC in North America is expected to grow at a compound annual growth rate (CAGR) of 13.5% in volume and 15.9% in revenue between 2013 and 2019 with the Mercury and Air Toxic Standards (MATS) as the primary market driver, thus offering an attractive opportunity for lignin-based PAC . As a result, the authors were tasked to further investigate the market opportunity for PAC from biorefinery lignin waste.
In December 2011, the EPA signed the MATS rule under the Clean Air Act section 111 (standards of performance for new stationary sources) and section 112 (hazardous air pollutants) requiring coal-fired power plants over 25 MW to reduce their toxic emissions by April 2016 . The MATS called for existing and new power plants to cut mercury emissions by 91% from 2010 levels with a cost to power plants estimated at approximately $9.6 billion per year [38, 39]. The MATS were brought to the US Court of Appeals for the D.C. Circuit in April 2014, where the ruling was upheld in a 2–1 decision . On November 25, 2014, the Supreme Court of the United States (SCOTUS) agreed to hear the case by consolidating three cases (Michigan, et al. v. EPA, Utility Air Regulatory Group v. EPA et al., and National Mining Assoc. v. EPA et al.) focused on the limited question of “Whether the Environmental Protection Agency unreasonably refused to consider costs in determining whether it is appropriate to regulate hazardous air pollutants emitted by electric utilities” .
In March 2015, the SCOTUS over-ruled the MATS due to the EPA’s lack of consideration of the costs associated with MATS implementation . As a result, the EPA proposed supplemental cost of MATS data in November 2015, suggesting that the costs of the MATS “does not alter the EPA’s previous determination that it is appropriate to regulate air toxics, including mercury, from power plants” . A date to readdress the SCOTUS ruling on MATS has yet to be released. Regardless, the US Energy Information Administration (EIA) has reported that 77% of the nation’s coal-fired power fleet has or will have met the emission regulations by installing emission controls by 2016 [44, 45].
Powdered activated carbon for mercury sequestration
The combustion of coal feedstock in power plants releases mercury emissions into the biosphere where it is transformed into methylmercury, a neurotoxin [30, 46, 47, 48]. The USA contains three main coal producing regions: Western Region (approx. 53%), Appalachian Region (approx. 27.4%), and Interior Region (approx. 18.6%) . Mercury emissions are a function of both the mercury content and calorific value (BTUs) of the coal, which varies by coal-producing region . The Appalachian region generally has the highest mercury content (ppm) and the Western Region the lowest [50, 51].
Mitigating mercury from power plants can be achieved through various mechanisms including controls for particulate matter, sulfur dioxide, and nitrogen oxides ; the reinjection of partially combusted coal, known as The Thief Process ; and, the most effective mechanism, activated carbon injection systems (ACI) where the mercury-contaminated PAC is disposed safely in landfills or used as a concrete amendment [54–57].
Lignin-based powdered activated carbon
Lignin is approximately 60% carbon and has a structure similar to bituminous coal, thus providing an opportunity as a renewable high carbon feedstock for the manufacture of carbon fiber and activated carbon [17, 34, 58–60]. Activated carbon has been produced from high carbon content materials such as hardwoods, coconut shells, fruit stones, coals, and synthetic macromolecular systems . Activated carbon is used in liquid phase and gas phase applications  and may be used in various forms including powdered, granulated, and extruded activated carbon .
Scientists have developed lignin-based PAC products through physical and chemical activation pathways [4, 34]. Lignin-based PAC has been studied for its use in liquid phase applications ; however, in laboratory settings, NARA researchers have successfully applied lignin-based PAC in a gas phase application to sequester mercury from power plant flue gas streams (I. Dallmeyer, personal communication, November 10, 2015). Various performance-based, market-entry issues including, but not limited to, PAC porosity and mercury capture rates are currently under investigation [I. Dallmeyer, personal communication, October 15, 2015].
This paper provides a roadmap to identify and assess value-added markets for industrial products through an examination of lignin-based products. One value-added lignin product with potential, PAC, is used to further demonstrate a market analysis-based process for examining market opportunities for biorefinery lignin waste streams.
This research deployed a multi-phase market analysis-based process including a PAC vendor content analysis and survey techniques. A thorough literature review identified potential lignin-based value-added products. PAC was selected as an appropriate “low-hanging” opportunity for biorefinery waste lignin and, as such, was used in subsequent research phases. Phase I then analyzed web-based content of PAC vendors’ promotional marketing literature tailored to power plant buyers/users for their PAC products. And, phase II incorporated the phase I results into an exploratory e-survey of select PAC buyers/users in the US power generation industry. Combining these methods provides an exploratory market perspective on lignin valorization.
Phase I: PAC vendor content analysis
PAC vendors analyzed in the vendor content analysis (n = 8)
Print media access
ADA Carbon Solutions
Babcock Power Inc.
Carbotech AC GMBH
Carbotech.de/?lang = en
The goal of a content analysis is “to provide knowledge and understanding of the phenomenon under study”  and “to examine trends and patterns in documents” . Content analysis is used to isolate important service and product attributes, access attributes unpublished in peer-reviewed literature, and reduce the use of time-consuming buyer interviews .
This study used a summative content analysis  to identify and quantify specific terminology using a word frequency count (WFC) applied to the promotional marketing materials of eight US PAC suppliers. The WFC and text interpretation were categorized using a priori coding . Content analysis media included all material related directly to mercury sequestration from flue gas streams from the company websites, product brochures, and product tech sheets of eight US PAC supplying companies.
Vendor attribute development
Examples of attribute assignment to PAC suppliers’ web-based content
Print media content
“...tailored to meet your needs.”
“Reduced mercury emissions”
“...effective in removing many flue gas contaminants.”
“...plant-tested and proven...”
Proven Product Performance
“...90% mercury removal was easily attainable with...”
Proven Product Performance
“...an undisturbed supply of...”
“Our Advanced Performance Guarantee...”
“We can guarantee...”
Coders and coding
In order to assess the reliability and validity of a content analysis, two or more coders are required [72, 73]. This study used two coders, one graduate and one undergraduate student at Penn State University, to validate the reliability of the content analysis.
Phase II: PAC buyer/user survey
Buyers/users of PAC, that is, electric generating power plants with ACI systems, assessed the importance of the phase I product and service attributes, identified barriers to market entry, and evaluated market opportunity via an e-survey.
Buyer/user population development
The e-survey used SurveyMonkey (2015) and the data collection procedures were adapted from Don Dillman’s Guiding Principles for Mail and Internet Surveys . First, three electric generating power plants were contacted by phone and sent a pretest e-survey to discern question ambiguity and sensitive information. From the pretest, a modified and reduced five-question survey was emailed as a link via SurveyMonkey (2015) to all remaining electric generating power plants (n = 95) along with a cover letter explaining the purpose of the study and the confidentiality of responses. Follow-up efforts included three reminder emails at 1-week intervals.
The overall response rate was 26.6% (17/64) after adjusting for unreachable power plants (n = 34) due to erroneous contact information in the EPA (2011) online database. The adjusted population for this exploratory study included 64 electric generating power plants with valid contact information from the EPA’s most current available database . Of the 17 participants, 4 are located in the upper Atlantic coast region, 1 in Florida, 7 in the upper mid-west, and 5 in the western USA.
Phase I: PAC vendor content analysis
PAC suppliers utilize promotional marketing materials; product brochures, company websites, and product technical sheets to market products toward customers for the application of mercury sequestration from power plant flue gas. The print media consisted of 163 pages with 486 word frequency counts (WFCs); Product attributes received 408 WFCs, and service attributes received 78 WFCs.
Product and service attributes
Word frequency count of 13 product and service attributes identified in the content analysis of PAC vendors’ promotional marketing materials
9 product attributes
Word frequency count (WFC)
Proven Product Performance
Total (product attributes)
4 service attributes
Word frequency count (WFC)
Total (service attributes)
Total (13 product and service attributes)
The distribution of WFCs shows vendors’ strategy to promote their PAC products as competent in product attributes with less emphasis on service attributes. Product attributes captured 84% of the total WFCs, while service attributes captured 16%. To gain perspective on importance from buyers/users of PAC, this population was surveyed using the above attributes.
Phase II: PAC buyer/user survey
From the content analysis, product and service attributes promoted by PAC vendors were included in a PAC buyer/user questionnaire. In addition, questions were added to address barriers to market entry for a new PAC product and opportunities for PAC product substitution.
Powdered activated carbon product and service attributes
Question: [on a 5-point scale from 1 = unimportant to 3 = neither important nor unimportant to 5 = extremely important] How IMPORTANT to your plant are the following PRODUCT and SERVICE attributes in the purchase of your powdered activated carbon product?
Product Reliability was rated as the most important attribute by buyers/users of PAC (mean = 5), followed by Product Effectiveness, Proven Performance, Reliable Delivery, Delivered Price, and Product Efficiency (Fig. 5). The least important attribute was ACI Equipment Installation (mean = 2.58). The highest rated service attribute was Reliable Delivery (mean = 4.67), followed by Product Guarantee (mean = 4.25), and List of Usage References (mean = 3.83). The 10 product attributes (overall mean = 4.25) were, as a whole, rated higher than the 7 service attributes (mean = 3.53). Interestingly, PAC buyers/users rated Product Reliability, Effectiveness and Performance higher than Delivered Price, suggesting opportunities to differentiate products on performance attributes.
An alignment in marketing strategy between what customers find most important and how vendors market their products was found through a comparison of the vendor content analysis and the e-survey attribute importance. Buyers/users of PAC rated Product Reliability (mean = 5.00), Product Effectiveness (mean = 4.92), and Proven Product Performance (mean = 4.83) as the three most important attributes when considering a product for purchasing, while vendors of PAC, market Product Effectiveness (WFC = 60) and Product Reliability (WFC = 44), as the second and third most often compared to other attributes (Fig. 5). Buyers/users also rated Reliable Delivery (mean = 4.67) the most important service attribute; consistent with vendors’ promotional material emphasis with this service attribute mentioned the most, by far (WFC = 39). Surprisingly, Concrete Friendly was rated as relatively low in importance by PAC buyers/users (mean = 3.08), but vendors’ promotional materials mention this attribute the most frequently in their on-line promotional materials (WFC = 76).
Barriers to entry
Question: [on a 5-point scale from 1 = extremely unlikely to 3 = neither unlikely nor likely to 5 = extremely likely] Please indicate the top 3 barriers to a new lignin-based PAC product for your power plant.
Title V Permits (weighted score = 18), such as a permit required for any physical plant change or change in the methods of plant operation, and Operational Impacts (weighted score = 16), that is, any impact on plant operations such as down-time or equipment change-over, represent the top two barriers to market entry for a lignin-based PAC, followed by Compliance with Regulations (weighted score = 13), specifically, compliance with mercury emission regulations, and Unproven Performance (weighted score = 11), that is, a product not yet tested on a full-scale power plant (Fig. 6). Additional entry barriers to a new lignin-based PAC products mentioned by PAC buyer/users include Existing Vendor Contracts (weighted score = 9), Product Availability (score = 8), Cost (weighted score = 7), and Logistics (transportation and distribution concerns) (weighted score = 6).
Opportunities for substitution
Finally, the e-survey asked PAC buyers/users to indicate the likelihood that their power plant would test trial a new lignin-based PAC and their likeliness of purchasing a new lignin-based PAC from an existing vendor or a new vendor. The 13 respondents who answered the previous “…barriers to a new lignin-based PAC product for your power plant” (entry barriers) question were asked the following two questions:
Question: [on a 5-point scale from 1 = extremely unlikely to 3 = neither unlikely nor likely to 5 = extremely likely] Please indicate how LIKELY your plant is to consider a trial test for proof-of-concept of a lignin-based PAC, assuming similar price and performance as your current product?
Question: [on a 5-point scale from 1 = extremely unlikely to 3 = neither unlikely nor likely to 5 = extremely likely] If the trial test proved lignin-based PAC to be a comparable product, how LIKELY is your plant to purchase lignin-based PAC from an Existing Vendor, or a New Vendor?
Discussion and conclusions
(Phase I) PAC vendor content analysis to derive product and service attributes on which PAC products are promoted and sold
(Phase II) PAC buyer/user exploratory e-surveys to address the relative importance of the phase I product and service attributes and to examine entry barriers for new PAC products and the market opportunity for a lignin-based PAC.
The PAC vendor content analysis suggests that vendors tailor the content of their promotional marketing materials to convey salient company and product information to their customers. PAC vendors promoted the product attributes of PAC (WFC = 408) more frequently than service attributes (WFC = 78) as evidenced by higher overall word frequency counts (WFCs). Concrete Friendly (WFC = 76), Product Effectiveness (WFC = 60), and Product Reliability (WFC = 44) received the highest overall WFCs in vendor PAC promotions. Reliable Delivery (WFC = 39) and ACI Installation (WFC = 18) ranked as the top two service attributes in which PAC vendors promoted their products. The WFCs of the product and service attributes from the PAC vendor content analysis reveal that PAC vendor marketing of a cost-effective, well performing product that will accomplish the goals of the power plant is important to the strategy of PAC marketing.
Results from surveying the buyer/user population of US electric generating power plants revealed the 10 product attributes (mean = 4.25) in which PAC buyers/users purchase their PAC to sequester mercury from flue gas streams rated higher than the 7 service attributes (mean = 3.53) in which PAC buyers/users purchase their PAC to sequester mercury from flue gas streams. Product Reliability (mean = 5.00), Product Effectiveness (mean = 4.92), and Proven Product Performance (mean = 4.83) ranked the three most important attributes. Reliable Delivery (mean = 4.67), Product Guarantee (mean = 4.25), and List of Usage References (mean = 3.83) ranked as the three most important service attributes. The product and service attributes ranked by buyers/users of PAC for mercury sequestration indicated products for purchase consideration must be reliable in mitigating mercury from flue gas streams and effective in mercury sequestration and must have a record of proven performance in existing full-scale power plants.
Respondents indicated the top three barriers to entry as Title V Permit (weighted score = 18), Operational Impacts (weighted score = 16), and Compliance with Regulation (weighted score = 13). Buyers/users of PAC, overall, rated their likeliness to trial test a new lignin-based PAC for proof of concept relatively low at 2.47 (n = 13). However, they were somewhat more likely to purchase a proven (trial tested) lignin-based PAC from an existing vendor (mean = 3.00) or from a new vendor (mean = 2.92), suggesting that they would be slightly more receptive to a proven product than spending energy being part of the test trial process. This hesitation to trial test a new lignin-based PAC for mercury sequestration from power plant flue gas may be due, in part, to the PAC Title V Permitting process, concerns over possible operational impacts, such as power plant down-time, and/or apprehension for meeting emission regulations due to product switching.
This exploratory study has implications to industry, policy makers, and academia and provides insights to the PAC producing industry, biorefineries, and the pulp industry regarding the market potential for introducing a lignin-based PAC as a value-added option for mercury sequestration from power plant flue gas streams. Policy makers may better understand the impact and reaction of new rules on electric generating power plants and peripheral industries. Lastly, this work illustrates a framework for exploring value-added business-to-business product-market opportunities and, specifically, opportunities for lignin valorization with a particular application to lignin-based PAC for mercury sequestration from electric generating power plant flue gas.
Results of this study may be considered as exploratory due to the relatively small population size of 64 electric generating power plants with usable contact information and a limited response of 17 surveys. Whereas the process used in this study may be applied to multiple emerging lignin-based products across a wide array of industrial applications, this paper addresses a single lignin valorization market opportunity, lignin-based PAC. The findings, however, may lay the groundwork for future work exploring market opportunities in other business-to-business markets.
This work was funded by the US Department of Agriculture’s National Institute of Food and Agriculture (NIFA) Agriculture and Food Research Initiative Competitive Grant No. 2011-68005-30416, Northwest Advanced Renewables Alliance (NARA) project.
SC designed the study, developed the population, designed the survey, and analyzed and deduced the results. PS aided in designing the study as well as the survey. Both authors read and approved the final manuscript.
SC was a Masters of Science student of BioRenewable Systems in the Agricultural and Biological Engineering department at The Pennsylvania State University. He now works as a Research & Development Engineer at Saint Gobain CertainTeed. PS is a Professor, Bioproducts Marketing in the Department of Agricultural and Biological Engineering at the Pennsylvania State University.
The authors declare that they have no competing interests.
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