The project goal is to develop an innovative, non-catalytic high destruction efficiency, and low fuel consumption volatile organic compounds (VOC) incinerator to reduce VOCs from condensate tanks and other low heat value waste gas streams.
Advanced Cooling Technologies (ACT), Inc., Lancaster, PA 17601
VOC emissions from various sources (oil and gas storage tanks, landfills, etc.) are an increasing challenge that cause significant environmental and human health effects. The utilization of a thermal oxidizer is a simple and effective way to turn most of these VOCs to the less harmful carbon dioxide (CO2) and water. However, to meet more and more stringent environmental regulations, the fuel consumption to achieve sufficient high destruction efficiency not only causes increased operational costs but also can also generate an increased volume of greenhouse gases. In addition, the high incineration temperature results in more NOx formation from conventional incineration process. A cost effective, low NOx, fuel efficient thermal oxidizer with the exhaust products that can meet stringent environmental regulations will help to solve the aforementioned challenges.
The technology being developed in this project can be applied to several waste gas incineration applications including those from landfill gas, chemical plants, hospitals, oil and gas operations, and more. This technology holds promise for reducing undesirable VOC emissions by using effective heat recirculation from the hot reacted stream to extend the flammability of the reactants containing the VOCs. There are nomoving parts or catalysts involved. Its low fuel consumption, high destruction efficiency, and low capitaland operational costs are the key benefits associated with the technology, making it an attractive option when compared to alternative VOC removal systems.
1. Demonstrate Ultra-low NOx Combustion in the Scale-up Prototype
Under high-heat recirculation, the combustion reaction in the Swiss-roll can be sustained at lower (premixed) combustion temperatures (1000~1200ºC), resulting in extremely low NOx formation (< 1 ppm). ACT hosted Zeeco on June 22, 2016, to demonstrate this ultra-low combustion feature in the scale-up Swiss-roll prototype. The demonstration went well and Zeeco expressed interest in exploring the use of the Swiss-roll as an advanced incineration device. Table 1 shows multiple measurements of different species concentrations in the exhaust.
|Table 1. The NOx and other species measured from the exhaust of the scaled-up Swiss-roll.|
2. Demonstrate the Stable Incineration with Low Heating Value Biogas
Zeeco suggested that the initial potential application is for landfill biogas incineration. In the later life of the landfill, the heating value of the biogas is too low to have stable incineration by itself, and a significant amount of supplemental fuel is needed to sustain the combustion process. Since the Swiss-roll is able to have stable combustion with very low heating value feedstock, it can potentially be used in this application to reduce the cost of supplemental fuel. A simulated biogas (55% CH4 and 45% CO2) test was performed to demonstrate the low heating value combustion in the Swiss-roll incinerator.
|Figure 1. The lean limit of the low heating value biogas (indicated via equivalence ratio) tested in scale-up Swiss-roll. (click to enlarge)|
Figure 2. Left: The center of the previous scale-up Swiss-roll deformed due to high reaction temperature. Right: The new design Swiss-roll with modified center reaction zone (a solid cylinder with thicker wall) to accommodate higher flow rate and higher center reaction temperature.
4. Heating Applications
In addition to the potential landfill application, the ultra-low NOx combustion feature may be applied to other combustion-related devices. ACT recently had a teleconference with engineers from Trane, who is a leading manufacturer of heating and cooling systems. They expressed the interest on using Swiss-roll for the combustion device for residential and commercial heating applications. The motivation is due to the recent environmental regulation in California (rule 1111) that requires the NOx emission of those devices be reduced from 40 ng/J to 14 ng/J. While the Swiss-roll has been demonstrated to be able to achieve very low NOx combustion, it has not been demonstrated for heating application. To explore the possibility of using the Swiss-roll for this application, a method to extract heat from the Swiss-roll is currently being designed (Figure 3).
|Figure 3. Schematic of method to extract heat from Swiss-roll.|