LAYMAN S REPORT. Brief history and background

Transcription

1 LAYMAN S REPORT Brief history and background BioCoAl is a project of Duferdofin, which decided to exploit the opportunity to develop a revolutionary pyrolisis process: the Flash Carbonization TM. The pyrolisis process, well known also as carbonization, imply the transformation of biomass (generally wood) in natural coal (charcoal).the process is well known since 18; it consists in the combustion of the wood with lack of oxygen. This reaction, instead of consuming the wood, transforms it into charcoal, which is a valuable and light fuel. Charcoal was produced directly in the forrest, in order to avoid expensive and tough wood transportation, while charcoal could be easily moved to the users. Ancient Charcoal production units Wood preparation in a forrest charcoal production site Nowadays, the use of charcoal from biomass almost disappeared in the western world, while it s still common in developing countries of south america and middle east. The main reason of this evolution stays in the fact that the technological progress on LIFE5 ENV/IT/81 BioCoAl 1/7 Layman s Report

2 this process has been basically steady for a long time, the fossil fuel (coal) is cheaper and available, and the traditional carbonization process is polluting both the athmosphere and the soil. In the latest years, the environmental issue became more and more relevant: the use of fossil fuels generates greenhouse effect gases which our planet can hardly digest and the scientific world is looking for alternative solutions for energy production, stressing the point on renewable energies. The exploitment of biomass directly for power generation is not fully effective, its employ is limited to very specific areas and cannot be a solution for industry power needs, the eolic and hydro-electric power is a very good source but its incidence on the balance is small, the solar energy is still in a research stage. The BioCoAl idea The BioCoAl project wants to demonstrate that the old biomass charcoal, if sustained by a modern technology, can have its role in a future energy environment. The Flash Carbonization TM patent, proved in laboratory, permits to obtain a very high carbonization yield in a surprisingly short time, gaining productivity and efficiency on the traditional method; furthermore, being an industrial process, gives the possibility to recover all the pollutants generated by the process. Duferdofin tried to develop an industrial scale Flash Carbonization TM reactor in order to demonstrate the economical and environmental viability of natural coal for energy purpose. Biocoal carbonization unit Duferdofin, with a team of 7 people, built in S. Zeno Naviglio, Italy the carbonization plant. The plant consists in a vessel, 4 meter high and 2 meter wide, the reactor, where the process takes place. The reactor can bear a pressure of 25 bar and temperatures up to 1 C; it is equipped with special temperature probes, useful for process control, pressure gauges, weighing system and special valves for air inlet and gases outlet. Infact the system is fed by fresh compressed air and produces pyrolisis gases. Once the wood is inserted in the reactor, the process is ignited with electric heaters for few minutes and then it s self sustaining until the carbonization is completed. LIFE5 ENV/IT/81 BioCoAl 2/7 Layman s Report

3 Control panel Off course the setting of the plant hasn t been easy at all! The first trials were a complete disaster, our reactor was not as easy to operate as the small laboratory reactor! The setting and tuning period lasted about 12 months, and several improvement have been implemented to the plant, time by time, learning from each carbonization experience. Quick comparison Traditonal process Carbonization time Carbonization yield 25 hours 25% Biocoal process 2,5 hours 4% Finally, the team succeeded in finding the right configuration of the machine, and have been able to produce good charcoal in a very short time. The average carbonization time has been 2,5 hours, which is 1/1 of the carbonization time of the traditional method! The evolution of the process consists in three main phases: ignition/drying, carbonization and reaction end, well explained in the charts. Some operating charts and performances LIFE5 ENV/IT/81 BioCoAl 3/7 Layman s Report

4 Charcoal discharging after a trial run Run 61 Biomass Temperatures temperature C 4 3 T2C T2D T2E T2F From ignition (time=) a quick increase of temperature is noticeable at all reactor heights (T2C= top, T2F= bottom); typical pyrolisis temperature is between 5 and 6 C. Run 61 Wall Temperature temperature C 2 15 T1A T1B T1C T1D Tgas The wall temperature is monitored for safety and equipment preservation. Tgas indicates the temperature of exhaust: this heat could be easily recovered for co-generation. LIFE5 ENV/IT/81 BioCoAl 4/7 Layman s Report

5 Run 61 Pressure & Flows pressure bar g Flow Nm3/h P1 Inlet Outflow Pressure inside the reactor (P1) is kept constant during the process, the air inlet slightly decrease in order to keep temperatures under control, the outlet tends to increase due to the involvement of bigger volumes of biomass in the reaction. Run 61 Net Weight loss net weight kg 1 8 net WT The weight indication gives a clear idea on the status of the carbonization: given the net biomass weight and knowing the yield (4%), the reaction is completed when the net weight reaches the calculated value. LIFE5 ENV/IT/81 BioCoAl 5/7 Layman s Report

6 Run 61 Gas Analysis 25 2 concentration 15 1 O2 CO CO Gas analysis are necessary in case of implementation of catalist burner: they contain a significant percentage of Carbon Monoxide and minor parts of Hydrogen (not indicated) and Methane (CH4, not indicated). Results achieved The biocoal project succeded in setting the reator for charcoal production, this results give direct environmental advantages if compared with traditional carbonization kilns used in Brazil: The condensible by-products like tarry water and pirolitic acid are collected in specific tanks and can be sent for treatment without affecting the soil and the aquifer. The flue gases can be flared or oxidized by a catalist, and, in any case are collected, while the traditional kilns release these gases to the athmosphere. The yield is quantifiable in 4% vs 25% of the traditional kilns, meaning that the BioCoAl process is more efficient The quality of the Biochar is outstanding, even when produced with the same wood as the brazilian kilns, as reported in our partner from Hungary HAS lab analysis. See table. Results on dry basis Water Ash Volatile Sulphur Carbon Hydrogen Nitrogen Heating value Sample % % % % % % % KJ/kg Brasilian sample from eucaliptus BioCoAl sample from eucaliptus run 39 4,4,8 19, <,1 84,2 3,2, ,6,9 21,1,1 83,3 3,7, LIFE5 ENV/IT/81 BioCoAl 6/7 Layman s Report

7 Weaknesses The weakness of the plant has been proved to be the sensitivity to different moisture contents of the biomass charge; high moisture affects strongly the performance both from a time point of wiew and from a charcoal quality point of wiew. Conclusions The BioCoAl experience has been interesting and challenging, the application of a carbonization system for industrial purpose doesn t seem feasible currently, the replacement of old traditional kilns in developing countries is not supported by economic convenience and above all by environmental counsciousness. The present application for this kind of technology could be barbecue charcoal production in Europe, which is a great market with high added value, and it s currently refurbished by brazilian charcoal. Furthermore it could stimulate biomass intensive cultivation in several rural regions. LIFE5 ENV/IT/81 BioCoAl 7/7 Layman s Report