Contents lists available at ScienceDirect Biomass and Bioenergy journal homepage: www.elsevier.com/locate/biombioe Research paper Studiesforremovaloftarfromproducergasinsmallscalebiomassgasifers using biodiesel VasudevaMadav a,∗ ,DarpanDas b ,ManishKumar c ,ManojSurwade d ,P.P.Parikh b ,VirendraSethi b a National Institute of Technology, Karnataka, India b Indian Institute of Technology Bombay, Mumbai, India c Finar Limited, Mumbai, India d Agilent Technologies, Mumbai, India ARTICLEINFO Keywords: Biomass Gasifcation Tar GC-MS Biodiesel ABSTRACT Biomass gasifcation based electricity generation systems are emerging as an important component of the de- centralised energy supply systems in rural India. Each type of gasifer has diferent reaction conditions, tem- perature, residence time, pressure, feedstock, reactor design, and therefore the tar and particulate matter (PM) compositionsandconcentrationsarefoundtovary.A feldstudywasconductedona35kWedowndraftgasifer to measure and characterize the tar in producer gas using GC-MS, for rice husk and pine needles as the two biomassfeeds.Useofwater-basedscrubbersforremovaloftarandPMisprevalent,howeveritisoftenthecase thatsuchclean-upisnotadequateformeetingtheenginemanufacturers’requirementsforthequalityofintake gas. Limited attempts have been reported for the use of organic solvent based gas cleaning in small scale downdraftgasifersintherange15–50kWe.Inthepresentwork,toluene,naphthaleneandphenolwereselected asrepresentativecompoundsoftar,andmethyloleatewasselectedtorepresentbiodieselasanorganicsolvent. A bench scale packed bed scrubber was designed for 95% removal of toluene. An 86–97% removal of toluene from the gas stream was achieved, and similar results were obtained for phenol and naphthalene. Further ex- periments were carried out with actual producer gas from a 1 kWe downdraft wood gasifer. Pongamia pinnata based biodiesel was used as the solvent, and 88–92% of the tar removal from the producer gas stream was achievable. 1. Introduction Biomass conversion into producer gas through thermo-chemical gasifcation is one of the pathways for renewable fuels to supplement fossil fuels for thermal and power applications. Use of small scale ga- sifers in some parts of India, using wood, rice husk and pine needles, areplayingavitalroleinacceleratingdecentralisedruralelectrifcation usingsociallysensitivebusinessmodels[1].InIndia,anaverageof120 milliontonsofriceisgrownperyear,andisprocessedthrough140,000 smallandmediumscalericemills[2],whichgenerateabout26million tonsofricehusk.Pineneedlesarefoundinlargequantities(12tonsof pine needles per hectare per year) in the coniferous forests in the Hi- malayan region, locally accessible to communities that are otherwise considered remote for electricity supply through the grid [3]. Producer gas from biomass gasifers is known to contain tar and particulatematter(PM)intherangeof0.01–160g/nm 3 and0.1–100g/ nm 3 respectively [4,5].TarandPMimposepracticallimitationsonthe use of producer gas due to fouling of downstream process equipment, enginewearandneedformorefrequentmaintenance[6–9].Catalytical approaches have been used for large scale gasifcation systems to eliminate tar [10–13]. However, for small scale systems, cyclones and water-based venturi scrubbers are routinely used, with limited success in bringing the tar and PM concentrations within the range re- commended for internal combustion (IC) engines [4,5]. Such water- basedgascleaningalsoleadstoissuesofwastewatergenerationthatare seldom addressed for small scale low cost systems. Special attention is thereforeneededforgasclean-upfordowndraftgasiferpowerplantsin the scale of 15–50 kWe that are increasingly being deployed in India, moresobecausetheseplantsdonothavetheadvantagesofscale,and/ or advanced technologies. Gas scrubbing using organic solvents instead of water is an option that has been successfully implemented as reported in literature [14,15]. However, studies on application of such oil-based scrubbing for small scale systems are limited, with some notable exceptions https://doi.org/10.1016/j.biombioe.2019.02.006 Received 28 May 2018; Received in revised form 21 December 2018; Accepted 6 February 2019 ∗ Corresponding author. Department of Mechanical Engineering, National Institute of Technology, Karnataka, Surathkal, India. E-mail addresses: vasu@nitk.edu.in (V. Madav), darpandasiitb@gmail.com (D. Das), manish331988@gmail.com (M. Kumar), manojsurwade@gmail.com (M. Surwade), parikh@iitb.ac.in (P.P. Parikh), vsethi@iitb.ac.in (V. Sethi). Biomass and Bioenergy 123 (2019) 123–133 0961-9534/ © 2019 Elsevier Ltd. All rights reserved. T