Improve Smoke Suppression

John Zink Company introduces the Steamizer^® - the latest high-performance steam-assisted flare tip offering the best technology available for smokeless burning of steam flares. Replacing the traditional Steam Assist (SA) flare, the Steamizer offers many technological improvements.

• Maximum smokeless capacity
• Leading-edge technology
• Minimize burn-back
• Reduce flame pull-down

Maximum Smokeless Capacity

A smoking flare indicates that unburned carbon is escaping into the atmosphere. Thus, smoking occurs when there is incomplete combustion of the flare gases. Incomplete combustion is a result of not having enough air mixed into the waste-gas stream, which is necessary for complete burning.

Figure 1

The Steamizer by John Zink^® is designed to inspirate a sufficient amount of air into the flame to ensure that smoking does not occur.

The Steamizer's smokeless capacity is based on two different sources of steam injection. These two sources are referred to as the lower and upper steam, see fig. 1. Most of the smokeless capacity is obtained from the lower steam nozzles. The lower steam nozzles educt air into tubes projecting into the center of the flare plume. The upper steam injection drives air into the perimeter of the flame. Both the lower and upper steam injections combine to provide the Steamizer with maximum smokeless capability.

Leading-Edge Technology

In 1996 John Zink engineers conducted, in our world-class Research and Development Test Center, the most extensive series of steam-assisted flare tests ever performed with the goal of developing a scientific understanding of the behavior and performance of steam-flare tips. Research resulted in several enhancements to the Steamizer flare tip, which have resulted in significant performance improvements.

Multiple-Port Supersonic Spider

Figure 2

The lower steam tips act as a jet, inspirating air into the lower steam tubes. Previous steam-flare designs relied on various configurations of sonic nozzles, with straight drillings, see fig. 2. However, when the steam leaves these sonic jets, it undergoes a series of contractions and expansions that results in shock waves. Noise is generated by these shock waves, and steam energy is lost.

Figure 3

John Zink developed the multiple-port supersonic steam spider (fig. 3) to eliminate noise emissions and steam energy losses. Each port is a converging-diverging supersonic nozzle. The unique design mitigates undesirable shock waves by ensuring that the steam reaches atmospheric pressure at the nozzle-exit plane.

In essence, John Zink's new multi-port supersonic steam spider provides increased air-eduction efficiency with reduced noise.

Lower Steam Nozzle

Figure 4

The interaction between the tube inlet bell and steam spider is critical to air-inspiration performance. John Zink uses a well-rounded inlet bell to reduce entrance-energy loss effects and thus provide more efficient air inspiration. Additionally, tests show the specific spacing between the spider and inlet bell proves critical to proper air inspiration.

Through extensive research and development, John Zink improved the tube inlet bell and placed the steam spider at an optimized location, see fig. 4. Both improvements have increased the smokeless capacity of the flare by improving the air-eduction efficiency.

Upper Steam Angle

The upper steam ring serves two purposes. First, it inspirates air into the perimeter of the flame, and secondly, it helps to stand the flame up vertically. Our testing indicates the angle at which the steam is injected into the flame has a great impact on the smokeless and noise performance.

Figure 5

Through testing, John Zink determined the optimum angle required to provide the maximum smokeless capacity while minimizing noise, fig. 5. Consequently John Zink Company provides the tip angle that offers the most efficient smokeless performance with the lowest noise.

Number of Tubes

Our testing indicates that increasing the steam tube-to-waste gas exit-area ratio can dramatically increase the smokeless performance of a steam flare. With this insight John Zink Company developed a series of standard tip configurations that allows customers to purchase the most cost-effective flare-tip, using only the number of tubes required to meet their needs.

Generation Comparison

Figure 6

John Zink has developed several generations of steam flare-tip designs, fig. 6. The first generation of steam flare tips was based on suppressing smoke through the use of only an upper steam ring. Our second-generation steam flares added the use of a lower steam source in addition to the upper steam ring. Now, the Steamizer, our third generation of steam-flare tips, is more efficient that our second generation flares.

Figure 7	Figure 8

Figures 7 and 8 compare the three generations of John Zink^® steam flares. These data indicate the best smokeless and noise performance possible for the flaring of propylene with only 42,000 lb/hr of steam available. This example shows that the Steamizer provides a 38% improvement in smokeless capacity and a 12% improvement in noise performance, compared to its predecessors.

Minimize Burnback

Figure 9

Internal burning is one of the most prominent mechanisms responsible for the failure of a flare tip. A flare tip will typically experience internal burning if it operates at a low waste-gas exit velocity in windy conditions. Under these operating conditions, the wind will create an internal recirculation pattern near the tip outlet creating internal burning, see fig. 9. Larger diameter flare tips are more likely to experience internal burning inside the flare-tip shell.

Burnback can greatly reduce tip life by deforming the structure and embrittling the tip material. To minimize internal burning, John Zink uses a center steam connection on some flares. The center steam consists of steam jets located near the base of the tip. The steam velocities assist in providing a positive pressure within the tip that minimizes internal burning.

Reduce Flame Pull-down

Figure 10

As wind blows across a flare tip, a low-pressure zone is created on the downwind side of the flare. This low-pressure zone pulls the flame downward causing the gases to impinge and burn on the shell, see fig. 10. John Zink provides the upper steam ring, which is placed around the perimeter of the flare tip, to stand the flame up vertically and minimize flame pull-down. This added protection results in an extended tip life.

Performance Prediction

The dramatic increase in environmental awareness throughout the world demands more accurate flare performance predictions. To meet industry demands, John Zink Company in 1996 set out to improve our flare prediction techniques. After conducting the most extensive series of flare tests in the world at our renowned Research and Development Test Center, we developed mathematical models, in the form of computer programs, to consider all of the critical flame characteristics. John Zink can now predict:

• Flame momentum
• Flame buoyancy
• Steam
• Momentum
• Steam jet efficiency
• Gas characteristics
• Smoking impact on radiation

Considering all these flame characteristics helps John Zink ensure that our customers receive the best prediction available.

Contact a John Zink representative for more Steamizer information.

John Zink Company, LLC
11920 East Apache
Tulsa, OK 74116
United States of America
+1-918-234-1800

email: info@johnzink.com