An energy that stems from the sun, biomass is a clean source that can help with supply-and-demand issues for the chemical industry while keeping the world a healthier place to live. And yet, there’s a lingering stigma about the use of biomass within the chemical engineering industry. Why? Some believe that the introduction of biomass into their energy-producing processes will cause a redo of their entire operations, which is not accurate. The truth is that industries can convert biomass into a gaseous stream that can be used in the same existing processes. The time has come for more industry stakeholders to evolve beyond understanding “why” biomass can produce valuable benefits to learning “how” to make better use of biomass resources.
An introduction to biomass
Biomass is purely organic material. When the sun’s energy is absorbed by plants through the process of photosynthesis, it can then be transformed into usable energy through direct and indirect means.3 It can be burned directly for heat or converted to renewable liquid and gaseous fuels through various processes and converted to energy through various processes, including:4
- Thermochemical conversion to produce solid, gaseous, and liquid fuels
- Chemical conversion to produce liquid fuels
- Biological conversion to produce liquid and gaseous fuels.
Prior to the mid-1800s, biomass served as the largest source of total annual energy consumption in the United States.4 According to the U.S. Energy Information Administration (EIA), the use of biomass fuels for transportation and for electricity generation is increasing in many developed countries as an alternative to fossil fuels and to avoid carbon dioxide emissions.4 In 2021, biomass reportedly provided nearly five quadrillion British thermal units and approximately five percent of total primary energy use in the United States and continues to be especially important in developing countries for fuel for cooking and heating.4
Most processes utilized today to make chemical products are still fossil fuel-based, but these resources are becoming increasingly limited. Despite the various consequences they pose and their dwindling availability, demand will continue to increase as supply decreases because the world’s population continues to be on the incline. This will lead to a supply-and-demand imbalance and products will become more expensive as they become more difficult to access. The automobile industry, in particular, will continue to experience significant difficulty in sustaining an appropriate level of production to match the demand. For example, the 1,3-butadiene chemical is a byproduct from petroleum crackers that produce ethylene from heavier hydrocarbons. Because petroleum cracker feedstock is trending towards lighter feedstock, 1,3-butadiene production from these crackers will reduce as well. Since biomass can be used to produce 1,3-butadiene, it can help to subside the supply-demand imbalance while reducing overall carbon dioxide production from the process.
There is a regular supply of raw material for biomass, however, which will help keep the rising prices of products more manageable, if it is utilized correctly. Plant or algae biomass can regrow in a relatively short period of time. Trees, crops, and municipal solid waste are also readily available and can be managed sustainably.
Biomass utilization: valuable products
Aside from butadiene, additional important chemicals that can be developed from biomass include ethylene, propylene, and methanol. In 2022, researchers at Princeton University in New Jersey compiled a study to rank the best chemicals that biomass can produce.5 The research was conducted through a computational analysis of common chemicals derived from petroleum. After developing simulation and optimization models, the study concluded that 24 of the 25 products tested would have a lower environmental footprint if produced using biomass as opposed to oil (under certain conditions). According to the research, the production of such chemicals using biomass could also reduce greenhouse gas emissions by up to 94 percent.5
The most common biomass feedstocks utilized for energy today are plants, wood, and waste.3 Although the burning of biomass does release CO2, the majority of that CO2 is recaptured by other growing plant life through their photosynthesis, thus qualifying biomass as a carbon-neutral energy source.6 Research conducted in 2021 to quantify the CO2 mitigation and removal potential of key bio-based pathways for the transport, power, construction, and iron and steel sectors in Europe found that the optimal use of biomass depends largely on the service for which it is deployed.7 Of all the options tested, biomass use for timber in the replacement of concrete showed to have the highest CO2 removal potential due to the minimal additional processing required after the conversion of roundwood into dimensional timber required and the adoption of wood products for construction.7 Other high removal potential pathways were determined to occur in the production of biochar, bioethanol, and biodiesel.7
Today’s available industry processes for biomass
The energy stored in biomass can be released in three ways to provide biopower technologies through renewable processes: burning, bacterial decomposition, and conversion to gas or liquid fuel.8 According to the U.S. Office of Energy Efficiency and Renewable Energy, most electricity generated from biomass is produced by direct combustion. After it is burned in a boiler to produce high-pressure steam for the production of electricity, biomass can serve as a substitute for some of the power created by coal in power plant furnaces through co-firing. Animal dung, human sewage, and other organic waste materials can be collected and decomposed by anaerobic bacteria that produce methane and other byproducts to form a natural gas that can be purified to generate electricity. Gasification and pyrolysis are methods of converting biomass into a gaseous or liquid fuel. Gasification produces “syngas,” a synthetic gas that consists primarily of a mixture of carbon monoxide and hydrogen that can be burned to produce electricity or an alternative to natural gas. Similar to gasification, pyrolysis is performed by heating biomass at a lower temperature and without oxygen to produce a bio-oil that can serve as a substitute for fuel oil or diesel for electricity production.8
One research article discussed three unique routes that utilize biomass to produce 1,3-butadiene and the associated co-products ethylene and propylene from lignin. For this research, steady-state simulation models were developed and the yield of useful products from these routes was studied. The highest yield of butadiene was found to be produced through a process that converts lignin to butadiene via syngas, dimethyl ether, and light olefins.9 A process that directly converts syngas to light olefins was determined to generate lower emissions of carbon monoxide and CO2.
Industry and environmental challenges
Turning to biomass as an alternative is not without its challenges, despite the encouraging benefits. Chiefly, an infrastructure for maintaining large volumes of lignin still needs to be developed in order to support a continuous supply and the required volumes for longevity. As a result, lignin is only used in small-scale plants today. According to one study, the supply chain for biomass production is associated with multiple other challenges, such as the variation in biomass availability, distinct characteristics of each species, uncertainties of the technology performance, logistics, and transportation issues.10 Additionally, external factors including high upfront capital, difficulties to secure financing to begin or sustain its operation, social awareness, and acceptance of biofuel contribute to supply chain difficulties. Mitigation and management solutions are proposed to improve supply chain effectiveness and efficiency.10
The United Kingdom and the Nordic countries of Europe, such as Poland and Finland, are credited with being among the locations that make the best use of biomass.11 Finland is home to three of the world’s five largest biomass plants.11 As more biomass plants presumably open globally and are introduced in the United States, some suggested best practices can help with stimulating better production and more lucrative options for the industry. One key measure is to ensure the possession of the best type of lignin to be used for the specific style of production. Similarly, the most appropriate process guided by the needed standards for quality is essential. If the stigma that persists within the chemical industry about the utilization of biomass is to cease, more professionals will need to become more knowledgeable about biomass- or lignin-based materials and how they can be converted into valuable chemicals or products. The unfounded and prevailing concern about biomass causing a process-changing shift in the workflow as opposed to the use of fossil fuels will also have to be overcome. Appropriate education and the establishment of best practices will successfully assist the chemical industry in making the necessary transitions for the sake of the environment and overall safety.
About the Author:
Namit Tripathi is a process engineer and product manager in the industrial gases energy sector. He has more than a decade of experience in operations, process troubleshooting, quality improvement, and product optimization. He is a peer reviewer for and editorial board member of multiple chemical engineering journals. Namit holds a bachelor’s degree in chemical engineering from Madhav Institute of Technology and Science in India and a doctorate in chemical engineering from Lamar University. For more information, contact [email protected].
References:
1. Ritchie H, Rosado P, Roser M. Energy. Our World in Data. 2022. Accessed online: https://ourworldindata.org/energy
2. Legislative and Regulatory Timeline for Fossil Fuel Combustion Wastes. EPA. 2022. Accessed online: www.epa.gov/coalash/legislative-and-regulatory-timeline-fossil-fuel-combustion-wastes
3. Biomass Energy. National Geographic. 2023. Accessed online: https://education.nationalgeographic.org/resource/biomass-energy/
4. Biomass Explained. EIA. 2022. Accessed online: www.eia.gov/energyexplained/biomass/
5. Seltzer MA. Study Ranks Best Chemicals to Make Using Biomass. Princeton University. 2022. Accessed online: https://acee.princeton.edu/acee-news/study-ranks-best-chemicals-to-make-using-biomass/
6. Environment. EIA. 2023. Accessed online: www.eia.gov/totalenergy/data/monthly/pdf/sec11_n.pdf
7. Patrizio P, Fajardy M, Bui M, MacDowell N. CO2 Mitigation or Removal: The Optimal Uses Of Biomass In Energy System Decarbonization. iScience. 2021. 24(7):102765.
8. Biopower Basics. Office of Energy Efficiency and Renewable Energy. 2023. Accessed online: www.energy.gov/eere/bioenergy/biopower-basics
9. Tripathi N, Palanki S, Xu Q, Nigam KDP. Production Of 1,3-Butadiene and Associated Coproducts Ethylene and Propylene. Ind Eng Chem Res. 2019. Accessed online https://pubs.acs.org/doi/pdf/10.1021/acs.iecr.9b00664
10. Lim CH, Ngan SL, Pei Qin Ng W, Shen How B, Lam HL. Chapter 19 - Biomass Supply Chain Management and Challenges. Value-Chain of Biofuels. 2022;429-44.
11. The World’s Largest Biomass Plants. Bester. 2023. Accessed online: https://bester.energy/en/the-worlds-largest-biomass-plants