Small Gas Turbine Powered By Wood Dust


Thread Starter

James Lam

We are interested to see if it is possible for us to build a small hobby brayton gas turbine using off-the-shelf industrial machinery and components. This gas turbine will run on fine wood dust as fuel to generate electricity. The design will comprise of the following components:

1) Biomass dust burner
2) Turbine wheel
3) Air Compressor
4) Generator
5) Recuperator

The sealed dust burner will be fed compressed air and ignited wood dust. The expanded air will escape through a nozzle to create high velocity gas that spins a wheel turbine. The turbine in turn, powers both the air compressor and electrical generator simultaneously. The waste heat, before escaping through a chimney, will be used to preheat compressed air before it enters the combustor.

I need help in determining the size and specs of the combustor (horizontal placement), air compressor and electrical generator. Back work ratio of gas turbines are usually in the range of 60% compressor and 40% generator, but I'm not sure about these figures when using off-the-shelf industrial equipment with varying efficiencies.

I need help with 'all/or either' the following:


A. Combustor
i) Approximate size? (diameter, length, etc)
ii) Nozzle size?

B. Air Compressor
i) Reciprocating piston type/ rotary screw type or others?
ii) Kw/Hp rating?
iii) Pressure rating? (psi, bar, mpa)
iii) Air flow rating? (cfm)

C. Electrical Generator
i) Kw/Hp rating?

I would like to obtain gas turbine experts help for our green gas turbine hobby project. What are you recommendations for the specs above, and what do you predict the overall electrical efficiency of this turbine with or without waste heat recuperation? How much net electricity (kwh) can we realistically obtain based on fuel feed of 10kg wood dust per hour?

Here are some useful data on characteristics of wood fuel..

1) 1 kg wood consumes 6.5kg / 8m3 of air (stochoimetric)
2) Maximum burn temperature of wood with stoking is around 1100C
3) Calorific value of dry wood is 19 MJ/kg