Transforming Residues into Solutions

Since the industrial revolution, humankind has been pouring tons of CO₂ and GHGs into our atmosphere.

It has then been a great challenge to accept that humanity’s activities, which have made life easier in many ways, are by far the largest contributors to global warming. At this point, there is a latent need to not only develop technologies that reduce our emissions to mitigate our carbon footprint, but also to start sequestering it. Biochar appears as the most efficient and cost-effective technology in order to do so. At Advanced Renewable Technology International - ARTi, removing carbon dioxide from the atmosphere has been part of our daily work since 2013, by building cut-edge pyrolysis systems for the production of biochar, activated carbon, and “green” carbon black for almost a decade. Our technology is a tool to not only create valuable products from residues, but also to help farmers,composting facilities, homeowners and landscapes integrate sustainable products in their operations and gardens. In the following article, we will show why “Carbon Sequestration with Biochar is a Business Opportunity for Biomass Producers,” farmers, businesses, and anyone ready to jump in carbon sequestration opportunities with biochar.

Biochar is one of the best tools to fight against climate change and can be profitable at the same time. This article explores the capabilities of ARTi´s Biochar Production Units (BPUs). After doing so, we will explore biochar production itself and carbon balance. Finally, we will emphasize on the opportunity presented with the biochar technology and the profitability behind biochar and our systems. Overall, this will be a comprehensive study on how to transform biomass residues into profitable carbon products and help the planet based on our experience in biochar production.

What is seen in the figure #2 below is the render of ARTi’s BPU, containerized mobile systems that can be placed anywhere in the world. It is able to pyrolyze a wide range of organic feedstock, with minimum labor requirements, as we are looking at a fully automated operation. Our units are able to sequester from 4 tons to 20 tons of CO₂ per day. All of ARTi units are housed in a recycled 40 ft container. ARTi’s BPUs are capable of transforming forestry, agricultural, and industrial residues into biochar with “pyrolysis,” heating biomass residues at high temperatures in the absence of oxygen. Otherwise, these residues would be either burned or decompose in the environment.

Important pyrolysis parameters, as well as biomass and biochar properties of the feedstock pyrolyzed, are listed below in Table #1. Biomass moisture content is quite relevant as it would affect the biochar yields and energetic content in order to ensure this thermochemical process is carried out. Parameters of the biochar produced relevant to carbon sequestration are shown: biochar yields, ash content, organic C, and recalcitrance of the carbon are some of the most important factors to consider to determine the capacity of sequestration and biochar quality produced. The purpose of Table #1 above is to show how different feedstocks types and organic material overall behavior based on our experience with specific scenarios. Even within each category, we have some slight differences.

Based on the previous information, a cradle-to-grave Life Cycle Assessment (LCA) for soils is performed, a comprehensive assessment of the product’s impact to the environment. The reactor’s manufacturing carbon footprint, the biochar production emissions, and its supply chain are taken into consideration (as shown in Figure #4). Considering the characteristics of the biochar produced, thecarbon credit issuing platforms generate a carbon credit ratio generated per ton of biochar produced as an output.

For the purpose of the study, we will focus on one representant of forestry, agricultural, and industrial residues. In the case of bamboo, it presents low ashes (<12%), an Organic C > 50% so we can define it as a good biochar product for high carbon sequestration. The expected carbon ratio result is 2.4; however, it does present the highest biochar yields. Those results are something we could expect, as we would be needing to find an equilibrium between the amount of biochar produced and the amount of carbon content within it. Considering nutshells as the representative of the agricultural residues category, it shows as the ideal feedstock to process. As seen in Table 1, we will be having: low ash content, highest Organic C, and high biochar yields. On the expected carbon credits ratio, we will have the same as in the case of bamboo; although, we will have an increment in the amount of biochar produced. Finally, referring to chicken litter, we have high ash content, low Organic C, and the highest biochar yields in the table. Those variables are reflected in the carbon credit ratio, mostly below 1. Note that this biochar might not be the “best” to sequester carbon, it will have a very interesting nutrient content besides the carbon sequestration value.

To show the profitability of the project, where economics are truly influenced by biochar and biochar characteristics, as well as the pyrolysis conditions. At the top of Figure #5 below, you will be able to review three boxes, one for each category previously considered for it. All of them present the Capital and Operational Expenditure (CAPEX and OPEX) per ton of biochar produced.

Two revenues are considered for this: Carbon Credits and Total Revenues. At first sight, industrial residues seem to be the best option with the lower expenditures; however, if we consider the economics in terms of NPV, it is the lowest one. As mentioned before, this feedstock category has the highest yields and therefore better OPEX/CAPEX per ton, but it does not have the highest carbon credit ratios and therefore sales. If we focus on the nutshells, it presents the highest NPV. This feedstock achieves a balance between yields and carbon credit ratio, translated into a good economic performance for the project. Finally, we have the forestry residues that fall into the middle of the economic performances with NPVs between $100K and $250K.

To emphasize, we will focus only on nutshells. In Figure #6, at the left you will be able to see a picture of the nutshells before and after pyrolysis. Followed on the right side by a summary table with a couple of pyrolysis and biochar parameters:

Using a single train reactor, operating 280 days per year, an NPV of $460K is expected to be obtained during the first five years of operation. We forecast to sequester about 1,300 tons of CO₂ per year. For this model, we just considered two revenue streams of the many available: Biochar and Carbon Credits sales. Operational costs were included in the calculation.

As shown, nutshells is just an example of how green technology is a sustainable and profitable investment. ARTi team’s multiple academic backgrounds has made it possible to develop several biochar production systems and consultancies around the globe. We have offices located in IA, USA and Quito, Ecuador. The blue dots represent the consultancy services we have developed around the world, and the orange dots represent the equipment in place. We definitely look forward to helping more companies accelerate their journey and ours to a greener future.

Author: Bernardo del Campo, Matthew Kieffer, Melany Estrella, Lissette Cordova, Diego Guevara

(Printed in Issue 1, 2022 of Carbon Capture Magazine, View Carbon Capture & Storage Directory)