In the highly competitive ethylene market, purity is of the utmost importance, while speed of processing and certification assure a producer will be able to meet commitments at the optimum product price. But speed and purity don’t always go together. That’s why the entry of hybrid QCL/TDL laser technology into ethylene production as both a gas purity analyzer and certification device is immensely exciting to ethylene producers. A recent article in Hydrocarbon Processing by Emerson‘s Amanda Gogates and Jeff Gunnell explains how the QCL provides a real improvement in terms of speed, precision, reliability, and cost in the critical areas of the plant.
The figure to the right shows how the novel design of the QCL laser reduces the portion of the laser beam exposed to the air to near zero. The analyzer can combine up to six quantum cascade lasers (QCLs) and tunable diode lasers (TDLs) in a single system for multiple gas measurements in this zero-gap configuration.
QCL and TDL lasers are semiconductor devices that produce light in the IR region. They are fabricated to emit light at a desired wavelength, and are made to scan a spectrum using a laser chirp technique.
When the laser is pulsed with electrical energy to start the laser process, it heats up. As the temperature increases, the wavelength of the emitted light also increases. A laser chirp lasts about one microsecond. In this span, a spectrum of between one to three wavenumbers is scanned. The raw detector signal is then processed to convert it into a spectrum from which the concentration of analytes can be calculated. QCL and TDL lasers can be chirped at a frequency of up to 100 kHz, enabling many thousands of spectra to be gathered in a few seconds and processed to provide a strong signal with a good signal-to-noise ratio. Response time is a major issue in these applications, as well. In a QCL/TDL, the sample flows through a measurement cell where laser beams continuously analyze the gas. The response time is typically less than 10 seconds to achieve 90% of a step change.
Before exporting to customers, ethylene must be analyzed to ensure that it meets product specifications in a step that is critical to profitability. Traditionally, this analysis has been carried out using grab samples and laboratory analysis with GCs. However, components such as ammonia, methanol, nitrogen monoxide (NO), nitrogen dioxide (NO2) and hydrogen sulfide (H2S) can now be measured online in one analyzer using the hybrid laser technology. This multi-component measurement is valuable in product certification, which would normally take 3-6 instruments to measure. Speed is critical at this stage of the delivery process, but precision of measurement should not be compromised for rapidity. The QCL laser technology allows for both, and online, real-time product certification can be achieved.
In risk averse environments like ethylene production, the adage “if it ain’t broke, don’t fix it” usually applies. But when a newer technology can be shown to have significant bottom line impact without increasing risk, the new adage becomes “no brainer.”
The Hydrocarbon Processing article can be viewed here: https://www.emerson.com/documents/automation/optimizing-ethylene-production-laser-technology-en-4845068.pdf
Maintaining water quality for assets like boilers and steam turbines is essential to prevent corrosion, maintain efficient operation, and assure environmental protection. The first line of defense in water quality is, of course, pH measurement. But if your plant measures pH in high-purity water, you already know that the process can be costly and very high maintenance.
Now, there’s a new, very innovative and straightforward solution to the high-purity water pH measurement problem that allows the use of cost effective, long-life, low maintenance, general-purpose sensors in the operation.
It’s a better, less costly way to assure quality in your challenging high-purity water applications. Download the White Paper here to learn more.
All chromatograph systems provide a comparative measurement where the analysis is a comparison to a known “standard” and the “standard” is the calibration gas. The calibration gas system is critical to the accuracy of the analysis as the gas chromatograph is only as accurate as the calibration gas.
We’d like to invite you to the second webinar in our Gas Chromatograph Webinar Series – “Calibration Gases and How to Calibrate a Gas Chromatograph Correctly.”
This webinar will review how to select a calibration gas, the important features of the calibration certificate, and how to calibrate a gas chromatograph using the calibration gas.
WEBINAR #2: Calibration Gases and How to Calibrate a Gas Chromatograph Correctly
Tuesday, June 12, 2018
10 AM – 11 AM CDT (Houston)
Emerson’s GC expert Bonnie Crossland will lead this webinar. Sign up now and get insights on how to maximize your GC’s performance.
And if you missed Webinar #1 in this series: “GC’s Response Factors and Why They are Important,” you can still watch the recording on-demand HERE.
About the Gas Chromatograph Webinar Series:
Gas chromatographs perform critical measurements in a wide range of process and natural gas industries. In many applications, these measurements translate directly into profitability, process efficiency, and regulatory and contract compliance. That’s why optimizing the performance of your GC can have a big impact on your bottom line. To help users get the most from their GC over the course of its lifecycle, Emerson is offering this free webinar series, bringing together our GC experts to offer trusted insights and best practices, and providing answers to the most frequently asked questions and solutions to challenges operators may be facing in the field.
Are you faced with the challenge of meeting the measurement accuracy requirements of the Bureau of Land Management (BLM)? And do you have a plan of how you could ensure compliance while staying focused on production rather than gathering samples?
Gas producers must comply with the BLM 43 CFR 3175 regulations, which establish minimum standards for accurate measurement and proper reporting of all gas removed or sold from Federal and Indian (except the Osage Tribe) leases, units, Unit Participating Areas (PAs), and areas subject to Communitization Agreements (CAs).
The BLM rule provides a system for production accountability by operators, lessees, purchasers, and transporters. This rule establishes overall gas measurement performance standards and includes, among other things, requirements for the hardware and software related to gas metering equipment, reporting, and recordkeeping. The BLM rule also identifies certain specific acts of noncompliance that may result in an immediate assessment and provides a process for the BLM to consider variances from the requirements of this rule.
There’s a way to be compliant with these regulations while reducing measurement errors and the costs of complying with 40 CFR 3175. Simplifying the process can allow you to focus on production rather than gathering samples. The approach is to use the appropriate natural gas chromatograph (GC). For example, Emerson’s Rosemount™ 370XA and 770XA GCs reduce BTU measurement errors often found with spot sampling. The online sampling of field-mounted GCs eliminates the need for personnel to frequently travel to the Facility Measurement Point (FMP) to pull a sample; saving man hours and travel costs. The 370XA is ideal for C6+ applications while the 770XA is ideal for C9+ applications or where hydrocarbon liquids may be present. Both are compact in design, don’t require a shelter, offer low utility gas consumption, and operate on 24 Vdc. This makes them perfect for remote locations.
The 370XA and 770XA provide analysis per requirements of the Gas Processors Association (GPA). They offer fully pre-engineered custody transfer application solutions that provide accurate and repeatable measurement analysis for the heating value of natural gas (§§3175.118).
In addition, the use of an advanced GC software solution such as the Emerson MON2020 further simplifies compliance and reduces maintenance and operation costs. The software gives you complete control of the GC either locally or remotely. You can store 88 days of analysis results, over a year of final calibration results, and over 1,700 chromatograms. The analysis report provides heating value and relative density.
In total, a straightforward evaluation of technologies can save natural gas operators both time and money. Managing compliance using the appropriate gas chromatograph not only meets BLM 43 CFR 3175 regulatory requirements, it saves substantial time and money while allowing the user to employ a familiar, proven, and highly accurate technology for the job.
Do you use GCs to meet BLM requirements? What is your approach?
The new Rosemount™ 6888C In-Situ Oxygen Analyzer can help you lower energy consumption and costs while minimizing emissions resulting from combustion processes. The robust Rosemount zirconia sensing cell features an acid-resistant option with catalytic beads to increase cell lifetimes in the presence of sulfur and other poisoning agents in flue gas.
The latest addition to the Rosemount 6888 portfolio can be configured as a blind, stand-alone transmitter with HART® or FOUNDATION™ Fieldbus communications, or with the Rosemount 6888Xi or Oxymitter remote electronics, or with an Emerson™ Wireless 775 THUM™ Adapter. The Rosemount 6888 analyzer is known for being simple to install, commission, and operate, and features a variety of calibration options. Calibrations can be performed manually, semi-automatically, or automatically. Semi- and fully-automatic calibration requires the use of a Rosemount IMPS 4000 or SPS 400 1B accessory or by ordering the integral autocalibration option. Additionally, the Rosemount 6888 portfolio provides industry-leading accuracy of ±0.75% of reading or ±0.05% O2, whichever is greater.