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Landfill & Biogas Solutions for H2S Measurement Applications

Landfill & Biogas Solutions for H2S Measurement Applications
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Landfill & Biogas Solutions for H2S Measurement Applications - 1

Application Note Landfill & Biogas Emerson Offers Landfill & Biogas Solutions for H2S Measurement Applications Applications As a by-product of recycled waste and raw materials, Landfills and Biogas facilities generate gases that can be used for multiple purposes such as fuel for boilers, dryers and heaters, power generators for engines and turbines, or even be supplied into a natural gas network. Comprised primarily of methane (CH4) and carbon dioxide (CO2), these gases may also include traces of oxygen, nitrogen and water, and in some cases contain hydrogen sulfide (H2S) at concentration levels of several hundred ppm. Local power production facilities often use the processed gas from these facilities to power the engines of the generators. Because the combination of H2S and moisture is highly corrosive, operators use gas analyzers to closely monitor the H2S levels in order to prevent corrosion, which can cause costly damages to the engine. Another common application of Landfill and Biogas usage is the production of Biomethane, where the extraction of CO2, H2O and H2S components allows the resulting purified gas to be injected into natural gas grids. Even though Biomethane is purified, low levels of H2S may still remain, and therefore local authorities often set strict regulation limits towards its use. For example, in Europe the H2S limit is 3.3 ppm. Rosemount Analytical offers electrochemical sensors for H2S in three measuring ranges: ■■ 0–50 ppm ■■ 0–200 ppm ■■ 0–2,000 ppm With Rosemount Analytical’s electrochemical cell, H2S is oxidized to sulfuric acid (H2SO4) which produces a current proportional to the H2S concentration. These inexpensive sensors are quite selective and sensitive down to low ppm concentration levels, however they require moisture and oxygen to maintain constant sensitivity, therefore an ambient air purge cycle is implemented. The X-STREAM Enhanced™ analyzer has an internal programmable logic controller (PLC), which is used to control the internal valve logic for implementation of the purge cycle. Purge and measurement intervals are set to 10 minutes each but can be easily configured to other field conditions. Integrated Solution In addition to H2S measurements at Landfill and Biogas sites, other measurements are needed. Methane (CH4) and carbon dioxide (CO2) are the main constituents and define the calorific value or quality of the gas and are measured with an IR photometer. Oxygen (O2) is a safety measurement performed with electrochemical cells or paramagnetic detectors. These additional measurements are done continuously in series with H2S when the H2S sensor is in measurement mode. When the H2S sensor is in a purge cycle, it is switched to parallel mode, relative to the active measurements. In addition to providing continuous accurate measurement analysis, the X-STREAM Enhanced includes built-in purge, calibration valves and pumps, providing a complete turn-key solution ideal for Landfill and Biogas applications. Typical Biogas Facility

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Landfill & Biogas Solutions for H2S Measurement Applications - 2

Landfill & Biogas The X-STREAM Enhanced analyzer provides accurate measurement of CH4, CO2, O2 and H2S combined into one single housing. For added installation flexibility, the analyzer is available in three housing options for Landfill and Biogas applications: ■■ General purpose 19 inch housing ■■ Field housing with IP66 ■■ Flameproof housing for hazardous area installations The landfill solution is provided as a complete system including all necessary sample conditioning, connections for sample and calibration gas, exhaust or vent, autocalibration solenoids, pressure and flow control,...

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Landfill & Biogas Solutions for H2S Measurement Applications - 3

Landfill & Biogas Table 1 - H2S Standard Measurement Performance Specifications Hydrogen Sulfide (H2S) Measurement Range (Sensor Dependent) Overgas Limit Operating Life Sensor Operating Temperature Gas Pressure Range Gas Humidity Range (Rel. Humidity) Thermostat Control (1) Related to full scale NOTE: These sensors require oxygen and moisture to work properly. Reference the Rosemount Analytical X-STREAM XE Analyzer Product Data Sheet for more information. Several configuration solutions are available, including a Four Channel and a Single Channel solution. Four Channel Solution (see Figure...

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Landfill & Biogas Solutions for H2S Measurement Applications - 4

Landfill & Biogas Emerson Process Management Rosemount Analytical Analytical Center of Excellence Emerson Process Management Rosemount Analytical Analytical Center of Excellence 10241 West Little York, Suite 200 Emerson Process Management Asia Pacific Private Limited MIDDLE EAST AND AFRICA Emerson Process Management Jebel AN Free Zone Dubai, United Arab Emirates ©2013 Emerson Process Management. All rights reserved. The Emerson logo is a trademark and service mark of Emerson Electric Co. Rosemount Analytical is a mark of one of the Emerson Process Management family of companies. All other...

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