ClearSign’s Duplex™ technology has the potential to reduce emissions from gas burners and increase their efficiency, and could be a key investment for oil and gas producers reliant on steam generation
Operators are frequently asked to reduce emissions as an environmental or regulatory concession, rather than as a business investment. Steve Pirnat, CEO of Seattle-based ClearSign Combustion, argues that this need not be the case.
Using ClearSign’s Duplex™ technology, Pirnat proposes: “We can not only dramatically reduce the emission produced in combustion but also improve certain operational characteristics than have inherent advantages in throughput and efficiency.”
Burners which produce low quantities of CO2, nitric oxide and nitrogen dioxide (pollutants collectively referred to as NOx) are already a market mainstay across many industries. But as regulations become even stricter, and energy efficiency becomes an even greater priority, energy-intensive industries such as oil and gas will be forced to make even tougher decisions on how to tackle the problem.
Commonly, reducing emissions from burners involves either flue gas recirculation (FGR) systems or selective catalytic reduction (SCR). The former meets some emissions requirements but can reduce the overall efficiency of the combustion process, and while the latter is more effective, it comes at a far larger cost and footprint. Pirnat believes that Duplex™ meets both issues head-on.
A new flame
The Duplex system works by installing a specially designed ducted ceramic tile above a standard burner. This turns a single large gas flame into thousands of tiny, more easily controlled flames. These flames are 80% smaller and, because they work by radiant heat transfer and not convective, are he says, “fundamentally more efficient.”
Duplex was developed as part of an interesting offshoot when ClearSign was developing its Electrodynamic Combustion Control (ECC™) technology, a system which uses computer-controlled electric fields to manipulate the movement of ions and control flame shape. Pirnat explains: “What the researchers discovered – which was somewhat shocking – is that they could achieve a dramatic reduction in emissions using the Duplex tile concept without any computer control at all.”
More efficient flames and fewer emissions with Duplex also lower the cost of operations and maintenance. With less ash deposited on boiler tubes, the equipment requires fewer shutdowns for de-coking. In turn, this can also lead to a reduction in failure rates.
The enhanced oil recovery (EOR) market in particular is dependent on once-through steam generators (OTSGs) and boilers to produce steam for oil extraction, and could stand to gain from such technology.
Analysis of Duplex operations suggest that Duplex provides a 4% saving against other potential solutions – a 3% saving on FGR and 1% saving resulting from better heat transfer.
With reducing emissions a priority for almost every industry, ClearSign is likely to be busy in the coming months and years. In terms of future oil and gas applications, Pirnat says the firm is already looking into applications in other areas, such as gas flaring, as well as integrating Duplex directly into the work of boiler manufacturers. But with 1,100 OTSGs in the US alone – 700 of which are in San Joaquin – Pirnat is excited about the “huge opportunity” available to both the company and operators looking to reduce NOx emissions and maximise savings.