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A gas-fermentation route, planned around each plant.
How industrial off-gas can become fuel ethanol, what decides whether a site is suitable, and which parts of the technology would be ours and which would be licensed.
How gas fermentation works
Gas fermentation uses specialised microorganisms that feed on gases instead of sugar. Conditioned gas is fed into a liquid medium. The microbes take up carbon monoxide, hydrogen and carbon dioxide and release ethanol, which is then recovered from the liquid.
Because it is a biological process, it works inside a window of gas quality, temperature and chemistry, and it needs a reasonably steady supply. That is why we start every project with the plant's own gas data.
Schematic only. Vessel design, flows and conditions depend on the chosen technology.
Process flow
From the plant's gas to a product a buyer can use. Select a stage to see what it involves and what decides it.
Industrial source
Candidate sources include off-gas from furnaces and kilns used in steel and ferroalloy production. Which streams qualify depends on what is in the gas, how much of it there is and how steadily it flows.
What decides it
- Share of carbon monoxide, carbon dioxide and hydrogen in the gas
- Volume, and how steady the flow is across a day and a season
- How the plant uses the gas today, such as heat or power
Gas conditioning
The gas is measured first, then cleaned and prepared for the fermentation step. Dust, tars and some trace compounds can harm the microbes, so the scope of conditioning is set by sampling at the site, not assumed.
What decides it
- Contaminants found in the gas assay
- Temperature and pressure at the tie-in point
- The gas specification of the chosen technology
Modular fermentation
Specialised microbes in a liquid medium use the gas as their source of carbon and energy and release ethanol. We plan compact modules sized for smaller sites. The fermentation process itself would come from a technology licensor.
What decides it
- Choice of technology and licence terms
- Gas flow available to the module
- Utilities and space on the host site
Ethanol recovery
Ethanol is separated from the fermentation liquid and purified to the grade the buyer needs. Fuel blending asks for a drier, purer product than some industrial uses, which affects the equipment and the energy needed.
What decides it
- Target grade and buyer specification
- Energy needed for separation and drying
- Handling of byproducts from the process
Market application
Our initial focus is fuel ethanol for petrol blending, sold to qualified buyers. Other applications may be considered where the specification and the demand allow.
What decides it
- Offtake terms and buyer qualification
- Product specification and logistics
- Regulatory approvals that apply to fuel ethanol
Process configuration, gas requirements and product yields depend on the selected technology and on conditions at each plant. This page describes an approach, not a performance guarantee.
Feedstock suitability
A stream is judged on measured data. These are the questions we ask of every candidate plant before going further.
| Factor | Why it matters | What we ask for |
|---|---|---|
| Gas composition | Microbes use carbon monoxide, hydrogen and carbon dioxide. The mix decides what the process can make from the gas. | A gas assay: CO, CO₂, H₂, nitrogen, oxygen and moisture. |
| Contaminants | Dust, tars, sulphur compounds and other trace species can slow or stop fermentation. | Sampling for particulates and trace compounds, and the plant's gas-cleaning history. |
| Volume and continuity | A module needs a steady supply. Frequent stops or swings in flow limit what a plant can reliably run. | Flow records over time, planned shutdowns and seasonal variation. |
| Pressure and temperature | Conditioning equipment is sized around these conditions. | Conditions at the proposed tie-in point. |
| Current use of the gas | If the gas makes heat or power today, taking it has a cost to the plant that has to be accounted for. | How the gas is used now and what it displaces. |
| Site and utilities | A modular unit needs land, power, water and safe access. | Available plot, utilities and the hazardous-area classification. |
Suitability is a site-specific finding. We make no assumption that any plant's off-gas qualifies until it has been assessed.
The modular facility concept
A standard set of skids and a fermentation module on the host plant's own footprint, joined to the plant at one gas tie-in point and one ethanol outlet.
Concept only. Layout, module count and equipment are set by the technology and by the host site.
Standardise what repeats
Skids, interfaces, controls and safety systems are designed once and reused, so each later site starts from validated engineering.
Adapt what is local
The tie-in, utilities, plot layout and permits differ at every plant and are handled site by site.
Keep the plant running
The unit sits beside the host's operations, so the mill's teams stay focused on making steel.
Product recovery
Ethanol leaves the fermentation vessel dissolved in liquid. It is separated, purified and, for fuel use, dried to the specification the buyer requires.
Fermentation also produces biomass and other byproducts. How these are handled, and whether they have value, is part of each feasibility study.
Separation and purification
Distillation and drying steps bring the product to grade. Their energy use is counted in the economics.
Storage and dispatch
On-site tanks hold product until it is collected by road tanker or another agreed route.
Fuel-grade focus
Fuel ethanol for blending is our initial focus. Other grades may follow where demand and specification allow.
Byproducts
Handling and any value of byproducts is assessed with the technology provider and the host site.
Technical feasibility factors
A project goes ahead only when all six hold at the same site. Feasibility work tests them with real data: gas samples, process simulation, laboratory testing and pilot planning.
Gas supply
Enough gas, with the right composition, available steadily.
Process fit
The gas sits inside the operating window of the chosen technology.
Integration
A safe, practical tie-in point and space on the host site.
Product quality
Ethanol that meets the buyer's specification.
Utilities and energy
Power, water and steam available at a cost that works.
Permits and safety
Approvals, hazardous-area design and emergency arrangements in place.
What is ours, and what is licensed
We want partners to know where Punarva Bio's own role ends and third-party technology begins.
What we intend to do
- Assess candidate sites and run the feasibility work
- Develop projects and arrange their financing
- Bring technology and engineering partners together
- Plan to build and operate modular units at host sites
- Sell ethanol to qualified buyers
What belongs to others
- The gas-fermentation process and its microorganisms, owned by technology licensors
- Equipment designs owned by suppliers
- Engineering designs prepared by engineering partners
- Any use of such technology would be under a licence agreed with its owner
Punarva Bio does not claim ownership of third-party process technology. This page does not describe any licence as signed.