Smokeless Flaring

Smokeless flaring is based on the principle of increasing the burning rate by the injection of steam into a flEune, by the creation of turbulence in the reacting gases and the inspiration of air, thereby reducing the formation of soot. Soot formation is also reduced by the water gas reaction, C + HgO = CO + H2, promoted by the addition of steam. 

From the above equation it is readily found that about 0.3 poimds of steam is required for smokeless flaring of 1 pound of hydrocarbon with a molecular weight of 28. This is in agreement with the result of an analysis of data on smokeless flaring (with the exception that no dependence on molecular weight was noted). 

---

Vapor recovery systems floating roof tanks pressure tanks vapor balance painting tanks white Cyclones-precipitator-CO boiler cyclones-water scrubber multiple cyclones Vapor recovery vapor incineration Smokeless flares-gas recovery... 

For non-smokeless flares (no steam injection) about 30% higher capacity can be allowed [59]. Therefore, the diameter of a non-smokeless flare stack is approximately (0.85) (diameter of the smokeless flare stack). 

Gibson, R. O. and Vinson, D. J., Design and Installation of Smokeless Flare Systems for Gasoline Plants, ASME, Paper No. 72-Pet-I2, 1972. 

Smokeless flaring is required by law in the United States (40 CFR 60.18, Chap. 1) for normal process flares (continuous flaring). However, smokeless flaring is not required by the EPA for emergency flaring, but local conditions and regulations may require smokeless flaring. 

The smokeless dare tip has been used successfully offshore to reduce radiation intensity levels and resulting flare boom length. Turndown of the different types of flare tips has been a problem but has largely been solved by the vendors. The smokeless flare tip without assist from water or steam, Coanda-effeet type, has particular promise for offshore application. 

Recent experience shows that stack diameters obtained by means of Figure 6-7 generally agree well with data for smokeless flare stacks. 

Complying with theoretical steam requirements for smokeless flaring may require using an imprac-... 

For NGL plants, emissions usually come from gas sweetening units when acid waste gas is burned or incinerated. Most frequently, the acid waste gas is used as a feedstock in sulphur recovery units or in sulphuric acid plants. While flaring is often expected in NGL plants, the major poison and pollutant of concern is S02- Most plants employ elevated smokeless flares or gas incinerators for combustion of all waste gas constituent, including tail gas incinerator in which H2S is oxidized to SO2 (Berkel, 2000) [7]. Such practices are not sustainable. CP can be implemented to reduce and/or eliminate gas flaring or incinerations beyond acceptable level as stipulated by local environment authorities. 

The recovered hydrogen sulfide gas stream may be (1) vented, (2) flared in waste gas flares or modern smokeless flares, (3) incinerated, or (4) utilized for the production of elemental sulfur or sulfuric acid. If the recovered H2S gas stream is not to be utilized as a feedstock for commercial applications, the... 

When flaring or incinerafion is practiced, the major pollutant of concern is SO2. Mosf plants employ elevated smokeless flares or fail gas incinerators for complefe combustion of all waste gas constituents, including virtually 100% conversion to HjS to SO2. Little smoke and few parficulafes or hydrocarbons resulf from fhese devices because gas temperatures do not usually exceed 650°C (1200°F), significant quantities of nitrogen oxides are not formed. 

---