Energy
Swiss-Roll Advanced Combustor
The ‘Swiss roll’ combustor is a unique device that integrates heat recovery with chemical reaction by wrapping the combustion zone around a spiral counterflow heat exchanger. The heat of combustion from the hot products is transferred to the incoming air (without mass transfer) resulting in a super-adiabatic reaction temperature at the center. This elevated reaction temperature can enable a stable, near-equilibrium reaction even with low heating value reactant streams. In other words, the excess enthalpy reaction extends the flammability limits of the fuel and enables ultra-lean, self-sustained combustion, eliminating the supplemental fuel that would otherwise be needed to incinerate low-BTU waste gas streams. Extensive experimental work and modeling have been performed to understand the effect of heat recuperation on the chemical reaction and parametric design optimization. Novel additive manufacturing methods with various high-temperature materials are currently being used to manufacture a wide range of scale Swiss-roll combustors. The Swiss-roll combustor can be applied for emissions control in oil and gas, chemical, process, and biogas industries.
Publications:
- Crawmer, J.; Chen, C.; Richard, B.; Pearlman, H.; Edwards, T.; Ronney, P. An Innovative Volatile Organic Compound Incinerator. International Conference on Thermal Treatment Technologies & Hazardous Waste Combustors, 2018, IT3-22.
- Adhikari, D.; Bhuripanyo, P.; Rao, P.; Radyjowski, P.; Chen, C.,; Ronney, P.; “Swiss-roll Combustor: An Innovative Enclosed Combustor for high Methane Destruction Efficiency and Ultra-low NOX Emissions,” American Flame Research Committee Industrial Combustion Symposium, 2023
- Radyjowski, P.; Bhuripanyo, P.; Chen, C.; Ronney, P.; “Swiss-roll Autothermal Ammonia Reformer for Gas Turbine Applications,” American Flame Research Committee Industrial Combustion Symposium, 2023
Developed by ACT, the Swiss-roll combustor is a unique, patented burner that uses efficient heat recuperation to reduce both supplemental fuel consumption and emissions by directly integrating the combustion zone inside a heat exchanger. By locating combustor inside the heat exchanger, most of the heat from combustion products can be recovered leading to very high thermal and combustion efficiencies.
Moreover, unlike conventional flares that operate diffusion flame, the SRC operates an ultra-lean premixed flame which enables burning both low and high BTU gases while maintaining high destruction efficiency and low NOx and CO emissions.
- Crude oil and gas tank batteries
- Upstream oil and gas
- Landfill gases and biogases
- Manure management in dairy farms
- Agriculture and food processing
During normal operation, the flare gas enters the center of the swiss-roll combustor, while combustion air enters via the inlet swirl channel where it is preheated to increase its enthalpy. The products of combustion exit via the outlet swirl channels. With excess enthalpy, the combustion is self-sustained in the center of the Swiss-roll at super-adiabatic conditions for a given equivalence ratio. A control system is used to control the air flow rate from the blower to optimize combustion. The required airflow rate is determined by the control system with inputs from flare gas flow rate, pressure, and combustor temperatures.
| Features | Benefits |
| High reaction temperature | Near 100% combustion efficiency |
| Low NOx emissions | Can meet current NOX and CO regulatory requirements |
| Fully enclosed combustor | No smoke or no visible flame – clear exhaust gas
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| Can handle low and high BTU gases | Reduced supplementary fuel consumption |
| Forced draft operation | No effect of cross wind; Easy startup |
| High turn down ratio | Wide operation range for both flow rate and composition • High destruction efficiency over wide operational range |
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| No air or steam assist required | Lower utility costs |
Typically, an EGF requires natural draft for combustion air while the swiss-roll combustor utilizes forced draft via a blower.
- For the same capacity, the SRC stack is smaller than an EGF. This leads to faster
construction and lower capital costs. - The SRC requires lesser refractory liner material compared to an EGF.
- There is no temperature control in an EGF, per se. Because it is driven by natural draft
and no stack damper exists, the amount of excess combustion air entering the
combustion chamber cannot be controlled. On the other hand, since the SRC used a
forced draft fan, combustion/excess air and hence emissions can be finely controlled.
A small amount of supplementary fuel is required at startup to attain super-adiabatic conditions inside the Swiss-roll combustor. Once this condition is attained, additional supplementary fuel is not required for continuous steady-state operation.
For most of the time, the Swiss-roll operates in the lean to ultra-lean combustion mode with H2O and CO2 at the exhaust. In the situation where there is a large spike in flare gas flow rate, the SRC may switch to the rich combustion mode in which the high-quality syngas will be generated. The high-quality syngas is easily flared out (to H2O and CO2) without generating any sooty flame that has a high thermal radiation impact.
Currently, a single Swiss-roll combustor can flare 100,000 SCF/day (70 SCFM). However, depending upon the available vent gas pressure, several Swiss-roll combustors can be
operated in parallel to increase the overall capacity.
The Swiss-roll combustor-based flare system requires components such as knockout drum, safety valve, flow meters, flame arrestor, and control system. This equipment overlaps with equipment for conventional air and steam assisted flare systems. A fan/blower is also required to provide air for combustion. Therefore, it can be installed seamlessly with existing flare infrastructure.
Furnace Cooling
Fundamental research in extreme temperature environments is essential for various scientific and industrial applications. The need for advanced characterization techniques, such as neutron scattering, is essential to study materials under extreme conditions. These conditions, often reaching temperatures as high as 1700 °C, are relevant in fields such as materials science, metallurgy, chemical reaction kinetics, condensed matter physics, and much more. With such wide applications, there is a large demand for high-temperature neutron experiments at large facilities such as Oak Ridge National Laboratory (ORNL). However, due to the limited neutron resources, most facilities remain overbooked and have lengthy wait lists for users to run experiments. One of the primary challenges faced in high-temperature neutron furnaces is the time-consuming cooldown of the test furnace. The vacuum environment in these furnaces lead to slow radiative cooling rates, especially when cooling from 1000 °C to 100 °C. The substantial cooldown time at these temperatures can take 2-3 times longer than the actual experiment itself, causing a significant waste of valuable neutron beam time and limiting the number of experiments possible.
Advanced Cooling Technologies, Inc. (ACT) has developed a groundbreaking cooling technology that addresses this challenge. This advanced cooling system circulates a neutron-friendly gas through the internal furnace body and onto the sample, dramatically reducing the cooldown time by a factor of 30. This significantly enhances the throughput of neutron experiments, allowing users to perform more experiments in the same amount of time.
Download the cut sheet here.
CO2 Capture
ACT, in partnership with Lehigh University, has developed a novel acid/base ion-exchange direct air capture (DAC) system that can utilize either a low-grade heat source medium or an electrically derived weak base solution to regenerate the capture sorbent. This DAC sorbent has demonstrated CO₂ capture rates of greater than 90% with thermal regeneration of the sorbet shown to release captured CO₂ at temperatures as low as 50 °C with over 90% of the CO₂ released at a temperature of 100 °C. This novel system uses widely available commercial adsorbent resins, which reduce cost and alleviate supply constraints. Additionally, the system design is easily scalable and can be implemented as a modular system to minimize manufacturing and deployment costs.
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