PYROLYSIS Thermo-Chemical Conversion HOME 8 8 Centre for Sustainable Technologies Indian Institute of Science, Bangalore ; http://www.cst.iisc.ernet.in/ Supported by DBT, New Delhi. This is a Beta Version HOME 8

Thermo-Chemical Conversion Introduction to Pyrolysis Pyrolysis is a method in thermal conversion technology, wherein solid fuels like biomass will be converted at high temperatures to vapour and gases in the absence of any oxidant The output can be condensed to ambient temperature to lead to water and some complex oxygenated hydrocarbons in the form of liquids and permanent gases like CO, H2, CO2 and CH4 along with some residual solid in the form of char The fraction of solids, liquids and gases will depend on the rate of temperature rise and the actual temperature to which it is raised 8 Centre for Sustainable Technologies Indian Institute of Science, Bangalore ; http://www.cst.iisc.ernet.in/ Supported by DBT, New Delhi. This is a Beta Version HOME 8

Thermo-Chemical Conversion Introduction to Pyrolysis Typically, volatiles begin to evolve at about 300 to 500°C depending on the actual biomass considered Drums built to carry petroleum tar and other crude oils can be used to produce char by burning away the volatiles Pyrolysis can be slow, fast and intermediate Low heating rate helps to produce charcoal High heating rates (of 1000 °C/s) with residence times of 0.7 – 1 s in a process called fast pyrolysis are used to generate liquids which can be directly used as fuel or for conversion to straight chain hydrocarbons. The liquid obtained has high viscosity and tar content Requires relatively low capital investment. 8 Centre for Sustainable Technologies Indian Institute of Science, Bangalore ; http://www.cst.iisc.ernet.in/ Supported by DBT, New Delhi. This is a Beta Version HOME 8

Thermo-Chemical Conversion History of pyrolysis The word is derived from the Greek words “pyro” meaning fire and “lysis” meaning decomposition or breaking down into constituent parts. Char is the first synthetic material produced by humankind It is reported that more than 5500 years ago in Southern Europe and the Middle East, pyrolysis technology was used for charcoal production New by products (tars, acetic acid, methanol, acetone) were obtained from wood as civilization progressed and new reactors and bio-oil recovery systems were designed At the end of the 18th century, technologies to recover and utilize condensable pyrolysis products got relatively well developed 8 Centre for Sustainable Technologies Indian Institute of Science, Bangalore ; http://www.cst.iisc.ernet.in/ Supported by DBT, New Delhi. This is a Beta Version HOME 8

Thermo-Chemical Conversion Main products Bio-oil A dark brown liquid and has a similar composition to biomass Suitable for co-firing because it can be more readily handled and burned than solid fuel Has a much higher density than woody materials which reduces storage and transport costs A vital source for a wide range of organic compounds and speciality chemicals The oil can be upgraded to either a special engine fuel or through gasification processes to a syngas Bio-char Helps in carbon sequestration Can be utilized in many applications as a replacement for other biomass energy systems The presence of biochar in soil helps to increase plant growth yield 8 Centre for Sustainable Technologies Indian Institute of Science, Bangalore ; http://www.cst.iisc.ernet.in/ Supported by DBT, New Delhi. This is a Beta Version HOME 8

Catalytic conversion to hydrogen Thermo-Chemical Conversion Processes involved in pyrolysis Catalytic conversion to hydrogen Biomass Liquids Vapours Pyrolysis Condensation Power generation Heat Gases Combustion Char 8 Centre for Sustainable Technologies Indian Institute of Science, Bangalore ; http://www.cst.iisc.ernet.in/ Supported by DBT, New Delhi. This is a Beta Version HOME 8

Thermo-Chemical Conversion Types of reactors The types of reactors: Fixed bed reactor: The solids move down a vertical shaft and contact a counter-current upward moving product gas stream The fixed bed reactors generally operate with high carbon conservation, long solid residence time, low gas velocity and low ash carry over These types of reactor are being considered for small scale heat and power applications. The cooling system and gas cleaning consists of filtration through cyclone, wet scrubbers and dry filters 8 Centre for Sustainable Technologies Indian Institute of Science, Bangalore ; http://www.cst.iisc.ernet.in/ Supported by DBT, New Delhi. This is a Beta Version HOME 8

Thermo-Chemical Conversion Types of reactors 2. Fluidised bed reactor: The fluidized-bed reactor consists of a fluid-solid mixture that exhibits fluid like properties, by introducing pressurized fluid through the solid particulate substance Provide rapid heat transfer, good control for pyrolysis reaction and vapour residence time, extensive high surface area contact between fluid and solid per unit bed volume, good thermal transport inside the system and high relative velocity between the fluid and solid phase 8 Centre for Sustainable Technologies Indian Institute of Science, Bangalore ; http://www.cst.iisc.ernet.in/ Supported by DBT, New Delhi. This is a Beta Version HOME 8

Thermo-Chemical Conversion Types of reactors Bubbling type: Provide better temperature control, solids-to-gas contact, heat transfer and storage capacity because of the high solids density in the bed. Heated sand is used as the solid phase of the bed which rapidly heats the biomass in a non-oxygen environment giving char, vapour, gas and aerosols The fluidizing gas stream conveys the decomposed biomass constituents produced out of the reactor Charcoal is removed by a cyclone separator and stored. The vapour is cooled with a quenching system, condensed into bio-oil and stored High quality bio-oil and liquid yield is about 70%–75% weight of the biomass on a dry basis Need small biomass particle sizes (less than 2–3 mm) to achieve high biomass heating rates 8 Centre for Sustainable Technologies Indian Institute of Science, Bangalore ; http://www.cst.iisc.ernet.in/ Supported by DBT, New Delhi. This is a Beta Version HOME 8

Thermo-Chemical Conversion Types of reactors Circulating fluidized-beds: Have similar features to bubbling fluidized-bed reactors except shorter residence times for chars and vapours. This results in higher gas velocity and char content in bio-oil than in bubbling fluidized bed reactors. One advantage is that this type of reactor is suitable for very large throughputs 8 Centre for Sustainable Technologies Indian Institute of Science, Bangalore ; http://www.cst.iisc.ernet.in/ Supported by DBT, New Delhi. This is a Beta Version HOME 8

Thermo-Chemical Conversion Types of reactors Ablative reactor: Mechanical pressure is used to press biomass against a heated reactor wall. Material in contact with the wall essentially “melts” and, as it is moved away, the residual oil evaporates as pyrolysis vapours Feed material does not much grinding. These types of reactor can use particle sizes up to 20 mm Configuration is comparatively complex Types are ablative vortex and ablative rotating disk 8 Centre for Sustainable Technologies Indian Institute of Science, Bangalore ; http://www.cst.iisc.ernet.in/ Supported by DBT, New Delhi. This is a Beta Version HOME 8

Thermo-Chemical Conversion Types of reactors 4. Vacuum reactor: Performs a slow pyrolysis process with lower heat transfer rates which results in lower bio-oil yields of 35%–50% compared to the 75 wt% reported with the fluidized bed technologies Can process larger sized biomass particles (up to 2–5 cm) 5. Rotating Cone Reactor: Reaction takes place upon mechanical mixing of biomass and hot sand, instead of using inert gas High bio-oil yield PyRos: Has a cyclonic reactor with an integrated hot gas filter (the rotational particle separator) in one unit to produce particle free bio-oil. Compact and low cost 8 Centre for Sustainable Technologies Indian Institute of Science, Bangalore ; http://www.cst.iisc.ernet.in/ Supported by DBT, New Delhi. This is a Beta Version HOME 8

Thermo-Chemical Conversion Types of reactors Auger reactor: Here, augers are used to move biomass feedstock through an oxygen free cylindrical heated tube 8. Plasma Reactor: Tar eliminated due to the cracking effects High electrical power and having high operating costs 9. Microwave Reactor: Energy transfer occurs through the interaction of molecules or atoms using a microwave-heated bed Drying and pyrolysis carried out in a microwave cavity oven Advantages: efficient heat transfer, exponential control of the heating process, enhanced chemical reactivity, reduces the formation of undesirable species, increased syngas yield 8 Centre for Sustainable Technologies Indian Institute of Science, Bangalore ; http://www.cst.iisc.ernet.in/ Supported by DBT, New Delhi. This is a Beta Version HOME 8

Thermo-Chemical Conversion Types of reactors 10. Solar Reactor A suitable means of storing solar energy in the form of chemical energy A solar concentrator helps develop high temperatures in the pyrolysis reactor This maximises the utilisation of feedstock available Faster start up and shut down periods compared to slow reactors 8 Centre for Sustainable Technologies Indian Institute of Science, Bangalore ; http://www.cst.iisc.ernet.in/ Supported by DBT, New Delhi. This is a Beta Version HOME 8

Thermo-Chemical Conversion Recommended methods & products Pyrolysis Type Reactor Heating Method Temp. (°C) Biomass Bio-char Slow Fixed bed Furnace or kilns <300 Walnut shell, olive husk, hazelnut shell Bio-oil Large scale Fast Bubbling fluidised bed Heated recycle gas 450–550 Agriculture residue, wood chip, fruit shell Medium scale Circulating fluidised bed Wall and sand heating Forest residue, municipal waste, dry wood, waste tyres Small scale Flash PyRos PyRos heating Grass, husk, wood dust Syngas Slow/Fast Microwave Electromagnetic >800 Rice husk, wood dust 8 Centre for Sustainable Technologies Indian Institute of Science, Bangalore ; http://www.cst.iisc.ernet.in/ Supported by DBT, New Delhi. This is a Beta Version HOME 8

Biomass harvesting or feedstock Thermo-Chemical Conversion Variable costs - a case study from the USA Items Percentages  Biomass harvesting or feedstock 23%–30%  Maintenance 17%–24%  Utilites 22%–25%  Labor 12%–19%  Grinding 7%–9%  Transportation 5%–7% Ref: Mullaney, H.; Farag, I.H.; LaClaire, C.L.; Barrett, C.J. Technical, Environmental and Economic Feasibility of Bio-Oil in New Hampshire’s North Country; Final Report; New Hampshire Industrial Research Center (NHIRC): Durham City, NH, USA, 2002 8 Centre for Sustainable Technologies Indian Institute of Science, Bangalore ; http://www.cst.iisc.ernet.in/ Supported by DBT, New Delhi. This is a Beta Version HOME 8

Thermo-Chemical Conversion Commercialisation Shell Technology Centre Bangalore (STCB) The conversion process is called IH2 (IH Square) Uses city waste, crop residue, wood/forest residue, energy crops and algae, which are then sorted, sized and dried. These are then fluidized where a proprietary catalyst system takes over The end-distilled hydrocarbon can yield gasoline, jet fuel and diesel Ref: Fuel from Garbage, Business Today, August 16, 2015 8 Centre for Sustainable Technologies Indian Institute of Science, Bangalore ; http://www.cst.iisc.ernet.in/ Supported by DBT, New Delhi. This is a Beta Version HOME 8

Thermo-Chemical Conversion Commercialisation Ensyn and DynaMotive have been dominating in North America since the 1990s among the companies dealing with fast pyrolysis . Both companies use renewable biomass, forest residues and agriculture wastes as the feedstock. DynaMotive Technologies Corporation emphasises the development and commercialisation of environmentally friendly energy systems based on fuels produced from biomass Developed a proprietary process which converts biomass pyrolysis liquor with lime to produce an organic calcium product called BioLimeTM It can be used for pollution control 8 Centre for Sustainable Technologies Indian Institute of Science, Bangalore ; http://www.cst.iisc.ernet.in/ Supported by DBT, New Delhi. This is a Beta Version HOME 8

Thermo-Chemical Conversion Commercialisation The figure shows Dynamotive BioLime Demonstration Plant, Vancouver, Canada 8 Centre for Sustainable Technologies Indian Institute of Science, Bangalore ; http://www.cst.iisc.ernet.in/ Supported by DBT, New Delhi. This is a Beta Version HOME 8

Thermo-Chemical Conversion Commercialisation Ensyn uses additional chemicals obtained from the process for food smoking and have broadened into producing renewable fuel products from biomass Developed biofuel – Renewable Oil (RFO) which can be used as a combustion fuel Feedstock used are: Hardwoods and softwoods, with or without bark Mill and forest residues Agricultural residues, including cellulosic residues from palm oil production and sugar/energy cane operations 8 Centre for Sustainable Technologies Indian Institute of Science, Bangalore ; http://www.cst.iisc.ernet.in/ Supported by DBT, New Delhi. This is a Beta Version HOME 8

Thermo-Chemical Conversion Commercialisation KiOR Based at Pasadena, Texas Converts biomass (primarily Southern Yellow Pine whole tree chips) into what it calls “renewable crude” through fluid catalytic cracking. The product called Re-Crude can be processed into gasoline and diesel using standard refining equipment. 8 Centre for Sustainable Technologies Indian Institute of Science, Bangalore ; http://www.cst.iisc.ernet.in/ Supported by DBT, New Delhi. This is a Beta Version HOME 8

Thermo-Chemical Conversion Commercialisation Renewable Oil International and Pyrovac are companies that use vacuum pyrolysis technology 8 Centre for Sustainable Technologies Indian Institute of Science, Bangalore ; http://www.cst.iisc.ernet.in/ Supported by DBT, New Delhi. This is a Beta Version HOME 8

Thermo-Chemical Conversion Future challenges Improvement of the reliability of pyrolysis reactors and processes Improve the quality and consistency of bio-oil Development of catalysts for bio-oil upgrading 8 Centre for Sustainable Technologies Indian Institute of Science, Bangalore ; http://www.cst.iisc.ernet.in/ Supported by DBT, New Delhi. This is a Beta Version HOME 8

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