Design and development of a 20 kW cleaning and cooling system for a wood-chip gasifier

Abstract

The present study was undertaken with the objectives to develop a filter system for a 20 kW engine application and to test the filter. It was observed that tar content in the gas ranged from 12.4 to 85 mg/m3 , which was considered on the higher side, in some cases, compared from an accepted limit of 50 mg/m3 . The 20 kW cleaning and cooling system for cleaning of producer gas was developed by calculating the gas flow and maximum retention time in the filter. The diameter of these three filters, viz., water scrubber, wet filter and dry filter was calculated from retention time and velocity in the filter, which was found to be 0.20, 0.40 and 0.50 m respectively, with filter height of 0.80 m. The developed filter was evaluated for reduction of tar in the producer gas after cleaning. The tar content in the producer gas after filtration by using the system varies from 24 to 53.52 mg/m3 . The tar absorption using this filter system was 99.35%, while the pressure drop varied between 10 to 25 mm of the water column. The system was also operated by coupling with a small capacity IC engine. The diesel replacement was found to be in the range of 65.66 %.

Multi-Stage Filter Designs for a Gasifier System

“…To obtain CFD results that are independent of grid resolution [10] the grid independence test was performed by gradually increasing the number of mesh cells of the filtration unit when the number of filters in the computational domain increases to obtain different grid densities. The number of mesh cells for square honeycomb substrate of 5 mm thickness for one, two, three and four filters was 603873, 628873, 638873, 643873 and the Euler number for the same was 46.8, 48.0, 49.0 and 49.5 respectively.…”

“…Gasification is the process in which the solid biomass material is converted into the combustible gas through several thermochemical reactions is called producer gas. Producer gas having tar and ash particles that adversely affect the operation and performance of the engine, therefore, it is necessary to remove the tar and ash particles before it is used as a fuel to run the internal combustion (IC) engine [10], [13], [14]. To meet the needs of the power generating unit such as IC engine, the syngas should be appropriately cleaned from fixed bed reactors before feeding to the running engine.…”