Technical and Field Experience of Downdraft Gasifier for Village Electrification

Suraj Pandey, Aadarsh UpretiKathmandu University (KU)

KU Team Gasifier Evolution and Experience

KU-Gasifier R&D Team

• Dr. Bivek Baral (Team Leader)• Mr. Sunil Prasad Lohani (Activity Leader)• Mr. Suraj Pandey (Research Engineer & Post

graduate student by Research)• Mr. Anant Bhusal (Research Assistant)• Mr. Aadarsh Upreti (Research Assistant)

Gasifier Research started from 2010 with support from Renewable Nepal

Research Budget: NRs. 6.5 million

KU-Gasifier

• Downdraft Gasifier (3-models)– Single stage– Two-stage– Open top

• 12-15 kW (electrical)• Water Scrubbing for cleaning TAR• Charcoal for additional cleaning the tar

Ankur Gasifier

• Installation in Sarlahi• Single Stage Gasifier– 2 number of nozzles

• Water cooling and cleaning– Rice Husk as primary filter– Fabric Filter as secondary filter– Gas Engine for Power Generation

KU-3 models of Gasifier

Manufactured in Local

Workshop at Banepa

Tar cleaning and cooling

unit manufactured

at KU-Mechanical Workshop

Sketch of KU Gas Cleaning and Cooling System

12

3

4 5 6

Legend

1. Inlet Cyclone2. First Scrubber3. 2nd Counter

Scrubber4. 3rd Scrubber5. Charcoal filter6. Outlet cyclone

A 12 kW (electrical) Reactor

The Reactor is the heart of the gasifier where solid biomass fuel is converted in to gaseous fuel (producer gas)

KU-Gasifier Disadvantage

• Till now continuous ash removal has not been designed and focused.

KU-Gasifier Design Up-gradation• Screw Augur is planned to be incorporated in

the gasifier system for continuous ash removal• At present batch feeding of ash removal

system is designed.

Ankur Gasifier

Features:

Continuous ash removal system.

Comparison

KU model• Site specific design

(specific fuels).• Research based

design for better fuel economy.

• Start up time 5-7 minutes

Ankur model• Designed specific to

limited fuels.• Designed for various

fuel operating at above rated fuel economy.

• Start up time 5-7 minutes.

Site specific design

KU model gasifier advantages

• Custom design for site condition.• Design parameters for various kinds of fuel

available in Nepal.• TAR formation nature is not the same for

every types of fuels.• Custom cleaning and cooling systems for

different fuel source.

R & D for future

• Planned to insulate the reactor with fire cement for better reliability and maintainability.

• High efficiency cleaning system for ULTRA CLEAN GAS.

• Low operation and running cost.

Our effort in cleaning system

Bluish flame is the indication of gas quality.

The greater the gas quality, the less is the operation and maintenance cost for gas cleaning and engine repairing

Ultra Clean Producer Gas Combustion

Photo taken during 1 month training on design of gasifier system at IISc, Bangalore 2012, 80 kW (electrical) combustion flame.

Thank youLooking forward to collaborate with AEPC

for R&D and dissemination.