Hydrocarbon Processing Issue 04 | Page 12

FLARE STACK ANALYSIS PROCESS In steam-assisted flares, the ratio of steam to vent gas is critical. Under-steaming leads to incomplete combustion, while over-steaming will reduce the efficiency of the flare. Visible smoke is a clear sign of pollutants being released into the atmosphere. Efficient regulation needs continuous compositional analysis to ensure the steam-to-vent-gas ratio is maintained at its most efficient level and complies with the CE target. Servomex’s system, comprising the SERVOTOUGH SpectraScan 2400 and the SERVOMEX H2scan working in combination, gives a continuous reading with a good compositional measurement. It measures 14 components, with an overall BTU value and individual component values. The SpectraScan 2400 is a Tunable Filter Infrared analyzer which can accurately separate light hydrocarbon components in the C1 to C6 range. The H2scan uses non- depleting thin film technology to provide a direct, real-time hydrogen measurement that is not cross-sensitive to other gases. This completely integrated system has no carrier gas and needs no recalibration or adjustment, so there are few, if any, parameters to affect the sample. The combination of these two technologies provides a detection system that is simpler and superior to traditional analysis, with considerably lower implementation and product lifetime costs. Continuous compositional analysis allows the system to help find the optimum point between over-steaming and under- steaming by fast, accurate reporting of the net heating value of the combustion- zone gases, taking flare control a step further than other methods. The SpectraScan/H2scan system is so repeatable it is often used as a benchmark to determine the performance of analyzers using Gas Chromatography or Calorimetry. SERVOTOUGH Laser 3 Plus Process or around Environmental regulations itoring of the world require close mon utants the flare stack to prevent poll The US entering the atmosphere. Agency Environmental Protection nds as currently lists 187 compou hazardous air pollutants. SERVOTOUGH OxyExact 2200 Used with a system such as the SpectraScan/ H2scan, a flare stack can be analyzed to obtain a continuous and precise reading with good compositional measurements. or SERVOTOUGH SpectraScan 2400 SERVOMEX H2scan SERVOTOUGH Oxy 1900 KEY APPLICATION TYPES: OXYGEN MONITORING REQUIREMENTS There is also a requirement to monitor and control the amount of oxygen (O 2 ) in the flare. Monitoring O 2 at the burner prevents a potentially explosive mixture of flammable gas and O 2 building up, eliminating the risk of it igniting and causing a flash-back of burning gases into the plant. Typically, alarms are in place to alert when the O 2 level exceeds 1%, so accurate and timely measurement of O 2 is an important factor in maintaining plant safety. P12 The recommended method of determining the O 2 level in a flare stack is to use an analyzer fitted with a magneto-dynamic cell, which measures the paramagnetic properties of the gas. Oxygen is paramagnetic where other gases are not, making the Servomex Paramagnetic cell in analyzers such as the SERVOTOUGH Oxy 1900 and SERVOTOUGH OxyExact 2200 one of the safest and most reliable means of monitoring the presence of O 2 in hazardous situations. Both analyzers boast an integrated pressure compensation system that not only compensates for barometric pressure, but also for back pressure variations from flare stacks, enabling emission compliance targets to be easily met. Alternatively, the SERVOTOUGH Laser 3 Plus Process Tunable Diode Laser (TDL) analyzer is optimized for the monitoring of O 2 in processes where such monitoring is vital for the safe, efficient and reliable running of the process, and is essential for safety applications. It gives a fast response to measuring O 2 in flare stacks, using the latest Wavelength Modulated Spectroscopy measurement techniques with unique Servomex signal processing to provide the most stable, repeatable results with minimal cross- interference from other gases. The Oxy 1900, OxyExact 2200 and Laser 3 Plus are all SIL 2 rated, for easy integration into safety systems. Waste gases from various points in the plant meet at the vent header. Reliable, accurate and continuous measurement of O 2 at the vent header is critical to keep O 2 content at safe levels, preventing an explosive mixture of gases which could have devastating consequences for the plant. In vented hydrocarbons, this safe level is 0-1% of O 2 , so low-level detection accuracy is paramount. The pressure of the vent header is generally dictated by the process pressures that connect to it, so the sample may be considered ‘pressurized’ (i.e. over 16psia). Servomex process analyzers have been developed with this in mind, operating with vent pressures ranging from 18- 45psia, and higher for some applications. Using these technology solutions, your plant flares can reach the highest levels of efficiency and safety, and better comply with all regulatory standards. Our O 2 solutions: servomex.expert/ video-oxygen P13