There are many challenges associated with gasification, especially when it comes to gasification of grasses, which are preferable for their high yield and low cost per dry ton. The biggest challenges are ash slagging, acid gas removal, heat transfer into the grass, optimal moisture content, ash disposal, and a very long list of other fascinating puzzles… (we’re hiring!) but today we’re going to talk about one challenge that seemed extremely easy at first glance: how do you load grass into the gasifier?

You’d think that loading grass would be easy. We sure thought so. But grass hates to flow. Even when chopped into tiny pieces it’s a pillowy, stringy, grippy mess that has an angle of repose over 90°.

Idea #1: Pour the Grass

Naively, we assumed that grass would flow somewhat like an ideal fluid, allowing us to use a simple, funnel-like hopper. We’d just attach the hopper to the gasifier input and dump in grass. Obviously the grass would flow out of the hopper and into the gasifier — where else could it go?