[bob29]

How are you heating it? How are you powering all the chippers, blowers, conveyer belts, and other machinery? Along with the transportation of crop residue to your facility, how much carbon is re-emitted with your consumption of all these industrial products of the primarily fossil fueled powered energy system?

[carbadtraingood]

Pyrolysis is an energy positive reaction. It requires an initial heat input, but after getting started it produces more heat than it needs. That heat can be used to generate electricity or warm water.

[bob29]

Pyrolysis is entirely endothermic - it requires applying heat to biomass. Pyrolysis yields a vapor that will combust in the presence of oxygen and release energy. The energy released in the combustion of pyrolysis products can be used to drive further pyrolysis. A "Top Lit Updraft Gasifier" is a simple apparatus to achieve this.

Capturing the heat from pyrolysis in this way does however convert the pyrolysis vapor from hydrocarbon into combustion byproducts, namely C02. This company claims to be condensing all of these hydrocarbons, not combusting them.

For a nice and understandable example of pure pyrolysis without combustion, there is this project [0] wherein an airtight vessel is loaded with biomass, heat/energy is applied with electrical resistive heating elements. The pyrolysis occurs and the resulting vapors are captured and stored as a low pressure vapor for later use in cooking or powering internal combustion engine.

[0]https://www.patreon.com/posts/story-of-thing-i-61916621

[dreamcompiler]

Pyrolysis could in theory be done with concentrated solar thermal energy. The issues would be:

-- How much mirror area [heat] would be needed?

-- Mirror geometry: Troughs may lend themselves to continuous processing and gas recovery a bit better than central point concentrators but they provide less heat potential.

-- Can the economics work if you only process when the sun shines?

[carbadtraingood]

Totally. I am currently experimenting with TLUDs for waste products from some forest land I own. I didn't realize they were also attempting to capture the gases from pyrolization rather than using them to continue the pyrolysis.

In that case, you are totally correct, they'll need an input heat source.