Light Coal: Development of a Torrefaction Reactor and Business System for Himalayan India (Reactor Testing, Pine Needle Fuel Evaluation, End User Value Propositions and Logistics System Design)

A three month long field research brought to light that the lack of livelihood opportunities in the Kumaon region of Uttarakhand is leading to outmigration of people from the state. There is a major need to develop sustained income and employment opportunities for the people in the region. The monoculture of pine forests shed huge amounts pine needles on the forest floor during the summer months. These pine needles, however, are the reasons for frequent forest fires in the region, strongly impacting its biodiversity. This makes a perfect case for the establishment of a business employing local people to produce energy out of pine needles. In light of this need, the prospect of biomass Torrefaction to produce a commodity fuel to meet the thermal energy needs for a variety of end users was investigated. This project was done in collaboration with Avani Kumaon, an organization working to create sustainable livelihood opportunities for the people living in the region. Pine needles procured from the Kumaon region were Torrified in a direct convectively heated packed bed reactor, a muffle furnace and a TGA (Thermo-gravimetric Analyser) setup at TU Delft to quantify Mass Yields at Torrefaction temperatures of 230oC, 250oC, 270oC and 290oC and residence times of 15 minutes, 30 minutes and 45 minutes. The Torrified product obtained was checked for its calorific value in a bomb calorimeter and the Energy Yields were established for the different process conditions. A Differential Thermo-gravimetric Analysis (DTGA) for the raw and Torrified pine needles was also performed to understand the trends in Mass Yields and this was compared to the trends in Mass Yields obtained for verge grass through a similar set of experiments. It was found that pine needles by themselves are a better fuel than verge grass, undergoing lesser amelioration of fuel properties (in terms of delayed and lower levels of degradation of volatile fraction of hemicellulose and cellulose) through Torrefaction. However, Torrefaction of pine needles is still justified as they are found very wet and prone to rot. Long term storage of pine needles for year- long sale of a fuel further underscores the need for Torrefaction. During field research in India, two batch reactor designs were also built and tested for Torrefaction using pine needles. The designs gave moderate –poor results for heat transfer to the pine needles, leading to the production of non-uniformly Torrified product. This underscores the need for further research on other reactor designs. However, the second reactor built gave better heat penetration than reactor 1 and hence its geometrical and operational parameters were selected for calculation pertaining to the business model. A final selection of process parameters gave an isothermal Torrefaction temperature of 250oC for a residence time of 15 minutes. This was based on the trends in Mass Yields, Higher Heating Values (HHV) and Energy Yields obtained through Torrefaction experiments and DTGA analysis. The impact of different process conditions on the business profits and the overall efficiency of the reactor also played a role in choosing this process condition. Field research in the Kumaon region was carried out to find out the value proposition for a variety of end users, from domestic cooking to gasification based power plants. The needs and preferences of the end users were established through interviews, generative “Design Sessions” and cookstove demonstrations. In the end it was established that commercial kitchens that use commercial LPG for cooking would benefit most from the use of Torrified pellets, as the cost of commercial LPG is high and its supply chain is not well established in remote areas. Due to the concentration of these businesses in the urban areas, it was decided to focus on the market in these towns. Initial market penetration of 5% gave a daily fuel demand of 1072 kg/day and a raw biomass demand of 8055 kg/day. A cumulative reactor volume 21 m3 would be needed to meet this demand. A logistics system was designed in which the pine needles will be collected on foot by women collectors at 1 Re/kg , aided by a ropeway system. The transportation of the fuel to the market using factory owned pick-up trucks was found to be the most feasible. A 6 year payback time was fixed to recover the capital cost of the plant. Overall, the business gave marginal profits in the first 6 years and strong profits after 6 years, underscoring the business potential for this concept. Although further research is needed to develop the technology before realization of the project, this novel method of simultaneous development of the technology and business system with contextual consideration has produced a promising foundation of a business with much potential.