Small Scale Waste Incineration

Basics

• This page aims to look at the application of Waste Incineration in the context of a scale similar to Burn Barrels BUT with thought taken to various potential forms of pollution, and ways to prevent/alleviate this.

Reasons for Doing So

• Disposal of Non-Recyclable Materials (In Areas where Large Scale Processes aren't used for this, just Landfilling) Such As:
  • Thermosets
  • Foams like Expanded Polystyrene etc
  • Hard to shred films (Although Plastic Film Recycling can be done with the right workflow)
  • Multilayer Films / Mixed Packaging Waste
• Privacy/Security ( "Burn Bags" )
  • So Important Documents, Expired Checks/Debit Cards etc
  • Although Shredding and/or Pulping are substitutes to an extent, the issue of local accessibility is another potential justification for small scale waste incineration

Potential Pollution Routes

Unburnt Hydrocarbons/Carbon Monoxide/DPM type soot

• This is the most straightforward, and the main solution is enough air and heat in the fire
• Granted Flame Temperature Emissions Curve ranges need to be taken into account (to an extent more heat = more NOx , less heat means more CO etc)
• Between the small scale+frequency though (compared to Mass Motorization or Grid Scale powerplants etc) this isn't too major of an issue

Dioxins

• Unlike CO and Hydrocarbons, Dioxins still do pose an issue as they Bioaccumulate
• How dioxins form, how to minimize this, and how to potentially scrub them from emissions needs to be investigated
  • A TLUD with Charcoal above and below the RDF may be able to trap the dioxins?

Heavy Metals / Misc Elemental Pollutants

• This is largely an issue of pre-sorting the waste
• Undyed Paper and Plastics shouldn't have this issue at all
  • Investigating what dyes may contain pollutants that could concentrate in the Bottom Ash etc is something to look in, especially if Ash Utilization is planned
• Magnetic Strips from Debit Cards and so on may have odd materials in them, granted 1 card per "batch" done every few months or so isn't too significant, needs to be looked into though

Fly Ash Bourne Particulate Matter

• This cannot be "burned up" unlike Diesel Particulate Matter / Soot type particulate emissions
• Given scale and frequency shouldn't be TOO huge of an issue, but more dedicated devices could address this with a rudimentary ESP unit etc

Existing Design Evaluation

Open Burning

• Worst Case Scenario, especially if in a pit (so air cannot enter from the sides unlike if done on a flat surface)

Pan Style Outdoor Fireplace

• Similar to Open Burning albeit with potentially different thermal characteristics (Better conduction or insulation than soil depending on material used (metal vs ceramic etc)
• Core Temperature:
• Flame Temperature:

"Paint Can"

Unventilated

• Core Temperature:
• Flame Temperature:

Natural Air Induction

• IE Holes Drilled in the Bottom and/or Sides for airflow, but no fans or blowers used
• Core Temperature:
• Flame Temperature:

Forced Air Induction

• Core Temperature:
• Flame Temperature:

55 Gallon Burn Barrel

Unventilated

• Core Temperature:
• Flame Temperature:

Natural Air Induction

• IE Holes Drilled in the Bottom and/or Sides for airflow, but no fans or blowers used
• Core Temperature:
• Flame Temperature:

Forced Air Induction

• Core Temperature:
• Flame Temperature:

Design Optimized for High Plastic / Oily Rag Loading etc

• The goal with this would be Volume Reduction, and/or Waste Stabilization (such that it is no longer a fire risk, and/or a Plastic Pollution risk
• The design consists of a unit that the Waste is Placed in which can swap between Pyrolysis, and Gasification / Combustion modes via an Air Valve, as well as a Flue Gas Scrubber / low tech Vapor Destruction Unit / Gas Flare
• The operating principle of this design is to separate the sooty burning of Plastic/Oily Rags etc from the “clean” combustion of Biomass / Charcoal
  • Improvements in Fly Ash / Particulate Matter emission MAY occur, but reductions in Hydrocarbon Offgassing/Pyrolysis Gas, Heavy Soot, other pollutants common in Plastic Heavy Waste Blends is the primary goal, not reduction in the Primary Combustor’s Emmissions
  • ALTHOUGH if pared with a well designed TLUD setup or similar low emissions firepit etc this benefit may occur as well

Main Hearth

• Either an expendable metal container (such as a paint can), or a more rugged design of Fire Brick / other Refractory Materials is used
• Means must be allowed for:
  • Easily and Ergonomically Transferring Waste into the Device
  • External Heating of the Contents (Via a Gas Burner or Electric Heating Elements
  • Addition of Air and/or Steam to Cook Off the Petcoke / Char that remains, as well as any Tar / Creosote
  • Easy and Ergonomic Removal of Bottom Ash and/or Clinkers
• Also the design should be constructed such that an Operator has a good idea of what is happening inside the device, either by sensors ( Pyrometers / Thermocouples , Oxygen Sensors from Automotive Market etc) or via a View Port
• Fail Safe Design / Means of SCRAM-ing the reaction via water quenching or a CO2 Fire Extinguisher]] etc are also welcome additions
• Monitors for leaks of Combustible Gases and Carbon Monoxide, as well as checking “burnup efficiency” are also welcome improvements

Optional Tar Scrubber

• Akin to low tech Wood Gasifiers , a sealed container inline utilizing Wood Chips , Sawdust, Charcoal , or even Granulated Activated Carbon will allow for any non-cracked Tar]] / Creosote to be adsorbed and later fed back into the hearth, or combusted
• This prevents the Combustor / VDU from becoming Flooded, and aids in design of that by making the flow a Single Phase Fluid free from Steam Hammer etc

Optional AGR Section

• Depending on what is being processed, Acid Gas Removal may be needed
• Steel Wool based Designs, or an Aqueous Wet Scrubber should suffice
• Main concerns would be Chloropolymers and Fluropolymers
  • Chlorinated Solvents / Polychlorinated Bisphenol etc COULD appear, but are largely absent from the modern market

Optional Gasometer

• Utilizing a Gasometer and/or Valves (and potentially a Diaphragm Pump or something similar if Draft (be it natural, or Forced Draft from the Combustor can not be relied on due to it being isolated with valves+shut off) can allow for the Main Hearth and Filters to be run Independently of the Combustor/VDU

Combustor / Vapor Destruction Unit

• This unit takes the Pyrolysis Gas , and later Syngas , and fully combusts it
• This can either be done in a Gas Flare running on Propane / another Fuel Gas or via a Tuyere type assembly blowing Fuel Gas (Potentially Pre-Mixed with Combustion Air) into the Hot Coals of a Charcoal Grill or TLUD Stove / Rocket Stove
  • A modified Solo Stove/Clone with a pipe fitted to the side going into the fuel/coal bed should suffice
  • This fire would need to be fed with (mostly) “clean” fuel such as Wood, RDF , or Charcoal etc
  • Material from the Optional Tar Scrubber MAY be added, depending on how that impacts Burnup Efficiency

Internal Links

• Small Scale RDF Workflow
  • Similar Concept, However Intense Waste Pre-Sorting and Preparation of Permissible Waste with the goal of producing a high quality fuel/energy (re Waste to Energy ) is the goal, rather than Volume Reduction (ie bags of garbage to a bit of ash) / Waste Destruction

External Links

• A Whitepaper by " Sustainable Sanitation and Water Management 2020" Titled "Incineration (Small-Scale) Factsheet"
  • The 55 Gallon Barrel Based Mobile Incinerator by Mavi Deniz Mentioned
    • Seems like it is barrel based forced air with a secondary combustion zone?
• "Current Developments in Biotechnology and Bioengineering - Waste Treatment Processes for Energy Generation - 2019" Chapter "Waste Treatment Processes/Technologies for Energy Recovery 4.1 Incineration"
  • Quote:
    • "For optimum efficiency, any incinerator should be focused on the “Three T's.” The Three T's stand for “time,” “temperature,” and “turbulence.” These Three T's play very important roles in determining the efficiency of an incinerator."
    • Also mentioned "multiple hearth incinerators" and "direct flame incinerators"
    • Also had a basic section on Pyrolysis, a basic one on Gasification, and some great diagrams
    • It also made a distinction between Incineration and W2E where Incineration is solely concerned about volume reduction and/or sterilization+stabalization, while W2E Prioritizes Energy moreso. This was interesting, albeit any system with good Solid Waste Sorting/Recycling shouldn't be doing Mass Incineration of Unsorted MSW
• Federal Remediation Technologies Roundtable - Soil, Sediment, Bedrock and Sludge - 3.6 Ex Situ Thermal Treatment (assuming excavation) - 4.22 Incineration (Old Page)
• Federal Remediation Technologies Roundtable Desorption and Incineration (New Page)
• EPA - On-Site Incineration: Overview of Superfund Operating Experience