This past week, our team has been focusing on the development of a few major design iterations for exploration over the summer in Malaysia. The three main designs under consideration include a cone design, a "Tin Man" design, and a "Jolly Roger" Design. The team researched these designs over the course of the past week and have been compiling thorough documentation on the various designs. The Tin Man iteration was discussed very thoroughly. This design uses an external fuel source to virtually "bake" the biochar. Off gas is used to further th pyrolysis until complete. It takes gas from the bottom and can be considered as a batch system. This is similar to the Jolly Roger, which is another batch system. However, this system takes gas off the top and uses the feedstock as a source of fuel. In contrast, the Cone Design is not a batch system, and requires constant maintenance and monitoring to refill with feedstock and remove processed biochar. This would allow the user to burn as much feedstock as necessary in one trial, but would require more maintenance during operation. The team will be working this week to continue to develop fleshed out plans for these designs including a comprehensive materials list, budget and risk register for each moving forward. Over the summer, Latifah hopes to build and implement these designs with a farmer in Malaysia! More updates to come :)
Following last week's change of plans, the team spent this week reviewing our original design ideas and preparing for our midterm report. Adam in particular was very busy, crafting our new plan for the rest of the term, focused on preparing for a summer of testing in Malaysia.
For the next few weeks we will focus on reviewing our original design ideas and determining which ones could be adapted for testing by Latifah. From this we will produce a comprehensive budget for the summer work, and determine a plan for the summer.
From our original review of our winter quarter designs, we noticed that we had mainly focused on smaller designs that could easily be assembled for a quick prototyping process. However this summer we are focused more on a permanent, proof of concept design. Specifically our aim is to determine whether cacao pods can produce a biochar that can be used to help communities in some capacity, either as a fertilizer, water filter, or other use. With this in mind, we decided that it may be more useful to construct a larger scale converter that could be used to produce larger quantities of biochar through out the summer.
However Wenxi pointed out a number of obstacles that come with constructing a larger scale design. Specifically, a number of things that we had ignored as low risk, such as convection currents, even heating through out the material, and exhaust gases, become much more significant factors on a larger scale that need to be properly accounted for. With this in mind, we decided to split into two groups moving towards next week. The first group of four will look further into large scale designs and how to construct them. The second, smaller group will construct a rough budget for the summer that we can continue to edit as the term progresses.
Following up on last week’s research, our team continued looking into the accessibility of testing materials for water, soil, and biochar. With regards to water quality home testing kits, there are some testing kits available via Amazon that can test for toxic metals, volatile organic compounds, and coliform. However, these are expensive (~$350), and it did not seem productive to be using our budget to be testing local water quality whose results could possibly be obtained by our local utility provider or via websites. In addition, the water testing kits were missing testing for physical appearance/aesthetics, something that we had learned is valuable to look into when we researched Ghana’s current water quality. This is because people do not want to drink discolored water (even though its water quality may be up to standards). In terms of soil testing, there is a soil lab in Ghana that can perform toxicity tests of the soil at farms where we are planning to work at. However, it was brought up that there is no point in testing the soil right after applying biochar because we would need to wait for the full growth of cacao plants to see any noticeable differences in soil composition before and after biochar application. In terms of biochar testing, most of the toxicology tests can be done in a certified testing lab while utility tests can be done by ourselves.
Originally, we planned to purchase cost-friendly and reliable testing kits that the team could eventually bring to Ghana to measure our local water and soil quality in order to test the effectiveness of these kits, but one particular question came up among all of us: what are we expecting to find using these test kits? We would not have any benchmarks to compare to, especially because we have no access to site-specific water or soil samples from the farms we are hoping to deploy our biochar apparatus at. We also have not been able to produce biochar to test from the cacao husks that TCHO gave us due to COVID-19. This is further complicated by our lack of access to the Environmental Engineering labs in Y2E2; only critical researchers are allowed access to these labs during the pandemic, so we would not be able to compare our results with laboratory equipment.
Because of all the uncertainty regarding testing and sample accessibility, we decided that it would be more productive to instead focus our remaining weeks of the quarter on scaling up our design since Latifah recently connected with a chocolate farmer in Malaysia who is enthusiastic about trying biochar. Last quarter, we had conducted literature review of existing designs and prototyped a very small design using cans. However, in order for biochar application to be useful, a much more substantial amount needs to be produced, especially since there are a LOT of cacao husks during harvesting season. In the next five weeks of the quarter, we plan to create a more comprehensive design with specific material requirements, so that we can order to them to Malaysia for Latifah to begin prototyping.