Emerson _Finding and reducing the “hidden costs” in gas chromatograph installations
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Finding and reducing the “hidden costs” in gas chromatograph installations White Paper Finding and reducing the “hidden costs” in gas chromatograph installations Introduction Gas chromatographs (GCs) are the workhorses of gas analysis in virtually all process applications. GCs are proven technology that provide real-time compositional data to control processes, supervise product quality, and monitor emissions. Because GCs are so common in hydrocarbon processing facilities, industry professionals tend to fall back on standard practices when evaluating a GC for a new capital analyzer project or considering optimizing existing installations. Operations or environmental personnel focus on purchasing a GC that can handle the application at the best price and only factor in the cost of the GC. This approach ignores some of the largest costs that are ultimately required for the installation and operation of the GC, which leaves huge potential savings in capital expenses on the table. It is time for industry professionals to look beyond the obvious in analyzer projects and recognize the enormous impact of “hidden costs,” and steps they can take to avoid them. The iceberg effect The cost of a gas chromatograph represents only 5 to 20 percent of the total cost of the project – just the tip of the iceberg. That leaves a significant amount of additional costs that may not be considered when selecting a GC. Those costs can include a protective shelter, in-house or contracted engineering, installation charges, instrument air, heated sample lines, utilities, training, and start up and check out (Figure 1). The shelter Figure 1: Iceberg of hidden costs When industry professionals hear the word shelter, what comes to mind is a free-standing room in which people and equipment are fully protected from heat, cold, and environmental conditions. As is discussed below, this type of shelter is frequently not required, but when it is, it will represent at least 40 percent of the entire project cost. In addition to the shelter itself, users must factor in 1 Finding and reducing the “hidden costs” in gas chromatograph installations White Paper the additional costs of the HVAC unit, purge system, area monitors and alarms, lighting, communication, and electrical distribution, as well as instrument air, plumbing, and vent headers. Engineering Cost for both in-house and contract engineering are significant on any project that involves bringing a physical structure into an industrial environment. These costs make up somewhere between 15 to 18 percent of the total cost of the gas chromatograph project. Installation Installation charges will make up 15 to 20 percent of the gas chromatograph project costs including construction of a concrete pad. For large shelters, a crane may be required and even without it, labor costs will still be incurred as the structure is secured, communication and power interconnects are made, and tubing and piping is connected to existing points in the plant. Instrument air Instrument air lines must be installed to the shelter, adding more costs to the project. These expenses include not only materials, but also the labor required to install and connect the hardware. An air-bath, heated GC can add thousands of dollars to the operational cost of air usage. These costs escalate if a purge system is required for the GC and shelter. Heated sample lines When required by the application, heated sample lines and probes can add additional costs to the project, especially for samples needing extended line runs. Unheated and uninsulated sample lines can save several thousand dollars in costs, but to prevent inaccurate analysis, one must closely assess the stream composition and its possible dew point and compare them to the known environmental conditions before foregoing heated sample lines. Utilities Users need to consider the utility costs over the life of a gas chromatograph as they can be significantly higher when operating a traditional GC with an air-bath oven compared to a field-mountable GC with an airless oven. These costs include power requirements and instrument air usage as well as carrier and calibration gas consumption. These significant “hidden” costs, which are often not considered when adding a new GC to a plant, account for 70 percent to 80 percent of the total installation cost of the GC. So what can be done to greatly reduce the total costs to install and operate a GC? 2 Finding and reducing the “hidden costs” in gas chromatograph installations White Paper Traditional air-bath oven GCs vs. field-mountable transmitter type What if your gas chromatograph didn’t need a shelter? When considering the capabilities of a gas chromatograph for a given application, it is important to factor in the choice of airless ovens versus traditional air-bath ovens. In many situations, the airless ovens of field-mountable, transmitter-type GCs will help to reduce operating expenses. Air-bath ovens rely on plant or compressed air to heat the analytical oven to a constant and optimal temperature, which means a temperature above the dew point and optimized for component separation. The incoming air must be heated to maintain the constant oven temperature and must also be hydrocarbon free to prevent any explosive risks. Air-bath oven GCs are designed for installation in an analyzer house. Because of repeatability issues and sensitivity to humidity and moisture, they must be installed in the field with additional climate control protection. On the other hand, airless oven, transmitter-type GCs are designed to be installed directly in the field without any additional protection. The analytical oven is partitioned within the housing of the GC and is heated by block heater/wrap-around heaters. Tight proportional integral derivative (PID) control maintains temperature stability and the thermal mass of the oven assembly transmits heat to the detectors mounted within the oven. The column’s location near the detectors and heaters allows for stable heating Figure 2: Field-mountable process GC throughout the analysis. The entire oven assembly is enclosed in an insulation packing, which limits the effects of outside ambient conditions on the analysis of the GC (Figure 2).    3 Transmitter-type GCs withstand rain, high humidity and a wide ambient temperature range — typically -20 ° to +60 °C (-4 ° to +140 °F) — without impact on their analytical performance. Housings are typically IP 65 or higher. The instrument housing is explosion-proof and there is no need for air purge to ensure rating. The typical area classification is Class 1, Zone 1, Ex d IIC, Ex d IIB+H2, T4 rating, Enclosure Type 4 — with agency approvals, such as ATEX, CSA, and IEC-Ex. Transmitter-type GCs consume less electrical power during initial startup and during normal use — often less than 150 watts. Because of oven and housing design, the field-mountable GC does not require instrument air for any functions. Therefore, continuous heating of “plant air” is not needed, further reducing the power requirements. Finding and reducing the “hidden costs” in gas chromatograph installations  White Paper The design of the field-mountable GC allows it to be mounted closer to the sample takeoff so the sample line itself can be shorter. The installed cost is lower, and that can be significant when heat-traced sample lines are used. Fewer problems will be encountered obtaining a representative sample due to the sample characteristics changing during transport. While the transmitter-type GC offers many advantages and cost reductions, it is not appropriate for all applications. The oven can house only up to three detectors, including one flame detector. Given the compact design and the heating method of the analyzer, the maximum oven temperature is lower than that of a traditional GC (180 ° - 200 °C) but can still be up to 120 °C. The lower number of possible valves, reduced space for columns and lower temperature capabilities can all limit the number of applications of the field-mountable GC in some instances in which high carbon number compounds need to be analyzed. Programmed temperature type applications — like simulated distillation — are not possible with the transmitter-type GC. Column configurations and oven temperatures for both the field-mountable GCs and conventional GCs do not differ significantly for the majority of applications, therefore cycle times are relatively equivalent. A complete analysis of natural gas up to and including C9+ hydrocarbon components, giving a measurement within 0.125 British Thermal Unit (BTU) in 1,000 BTUs, for example, is accomplished in a field-mountable GC in four minutes. The bottom line is that many if not most GC applications can use a transmitter-type GC and benefit from the potential cost savings. Evaluating the performance characteristics of air-bath versus airless oven designs is a must for every GC installation. Understand your choices in shelters Looking at the GC “iceberg” of hidden costs, some users may point out that even if they select a transmitter-type GC that requires no shelter, they still need to protect their personnel and/or other equipment from weather issues — a fair argument. With that in mind, it is important to understand the choices of shelters, many of which can save substantial costs. Sun shield A sun shield provides protection for single or multiple analyzers and their associated accessories such as carrier and calibration gases and sample handling conditioning systems. It protects the analyzer from the sun and provides partial protection from rain, snow, and falling objects. On a cost scale, the sun shield is one of the lowest. A starting price for a sun shield is approximately $20,000 not including the analyzers (Figure 3). 4 Finding and reducing the “hidden costs” in gas chromatograph installations White Paper In general, no HVAC equipment, area monitors and alarms, vent headers, or communication systems are required. There may be electrical distribution systems. Due to the minimum weight, shipping expenses are low compared to other protection solutions. There will be installation costs associated with securing the structure, connecting communications and power, and running tubing and piping from the sample point to the analyzer. With its small size, the sun shield may be able to be placed close to the sample point. This can save several thousand dollars in tubing and piping, especially if heated sample lines are required. Figure 3: Example of a sun shield Three-sided shelter Appropriate in size for multiple GCs, a three-sided shelter with its partially vented walls and overhung roof, offers additional protection against driving rain and snow over the sun shield. The three-sided structure may include interior and exterior lighting. On a cost scale, the starting price is approximately $60,000 without analyzers (Figure 4). In general, no HVAC equipment, area monitors and alarms, vent headers or communication systems are required. As the weight and size are larger than the sun shield, the installation costs will be higher. The larger size of the three-sided shelter may preclude it from being near the sample point, thus tubing and piping costs will also be higher. Figure 4: Example of a three-sided shelter Enclosures and cabinets Enclosures and cabinets both provide protection from the rain, snow and falling objects. In an enclosure, given its small size, there is generally only room for a single analyzer and a limited number of associated accessories, such as a small calibration cylinder and a sample conditioning plate. It may attach to a wall, pole, frame, or even a pipeline. A cabinet is a free-standing shelter that may hold a single analyzer or multiple analyzers, their associated accessories such as carrier and calibration gases, and a sample handling conditioning system. Figure 5 is an example of a cabinet. 5 Finding and reducing the “hidden costs” in gas chromatograph installations White Paper On a cost scale, an enclosure is one of the lowest with a starting price of $10,000. In general, no HVAC equipment, area monitors and alarms, vent headers or communication and electrical distribution systems are required. Due to the minimum weight, shipping expenses are the least compared to other protection solutions. There will be installation costs like the sun shield. Like the sun shield, the enclosure’s small size means it may be placed close to the sample point. A cabinet can be slightly more than a sun shield. The cost point is highly dependent on whether Figure 5: Example of a cabinet HVAC and gas detection equipment is supplied. Airbath oven GCs can drive the need for HVAC, especially in hot climates because airbath ovens generate a lot of latent heat, whereas airless ovens don't. A basic cabinet can start at $30,000 and can go over $100,000. In general, no alarms, vent headers, or communication systems are required. The installation costs are similar to that of a three-sided shelter. The advantage of the cabinet over the three-sided shelter is its smaller size, which means the cabinet can be installed closer to the sample point, saving several thousand dollars in tubing and piping. On the other hand, a three-sided shelter can accommodate more analyzers while the cabinet is generally more suited to housing two analyzers with accessories. Walk-in shelter or analyzer house A walk-in shelter is a large structure consisting of four walls, a door, a ceiling and a floor. It provides protection for multiple analyzers and the technician (Figure 6). It is suited for extremely hot or cold climates and is selected when the safety and comfort of the technician is a key factor. Common walk-in shelter sizes include 8 ft. x 10 ft.(1.8 m x 3.0 m), 12 ft. x 8 ft.(3.6 m x 1.8 m), 12 ft. x 10 ft. (3.6 m x 3.0 m) and 10 ft. x 25 ft. (3.0 m x 7.6 m). Often the walk-in shelters will have HVAC equipment, area monitors and alarms, cabling and trays, hazardous area compliance, vent headers, and communication and electrical systems. There are a multitude of possible options such as the number of doors, insulation level and type, and thickness of the walls and roofing materials. If there is a need for four or more analyzers, a walk-in shelter may be the best option due to its size and wall space (Figure 7). 6 Finding and reducing the “hidden costs” in gas chromatograph installations White Paper Figure 6: Exterior view of a walk-in shelter On a cost scale, a walk-in shelter is the most expensive. A small shelter can be $100,000 with larger shelters being more than $300,000. The shipping costs are high due to the weight and the installation costs are the most expensive as additional equipment like cranes can be required to put the shelter in place. The large size of the walk-in shelter prevents it from being near the sample point, causing tubing and piping costs to be high. Figure 7: Interior of a walk-in shelter 7 Finding and reducing the “hidden costs” in gas chromatograph installations White Paper Flexibility improves cost benefit Determining the type of shelter required to ensure proper operation of a gas chromatograph depends on several factors. Certain applications, such as those requiring the measurement of trace levels of hydrogen sulfide, need a temperature-controlled environment. A cabinet with gas detectors or a walk-in shelter would be the best choice. In corrosive environments, such as offshore, an enclosure, cabinet, or walk-in shelter is the preferred protection method. The ambient temperature where the GC will be located must be considered. If the coldest ambient temperature is lower than the operating temperature of the GC, then a temperature-controlled shelter will be required. The same applies for the hottest ambient temperature. It is also worth considering the safety and comfort of the technician. While the ambient temperatures of the location may fall within the operating temperature range of the GC, it might not be within the operating range of the technician. So the first question the user needs to ask when embarking on a new analyzer project is, “What is my application and do I require a traditional GC to achieve the needed results, or can I use a field-mountable GC?” The answer to that question will determine everything that follows and will impact the budget significantly. If the application and environment do not preclude it, a transmitter-type GC can be protected with a cost-effective sun shield or three-sided shelter so those are factored into the cost savings. Figure 8: Comparison of shelters Figure 8 shows the dramatic difference in costs that can be achieved using a field-mountable GC, which offers significant savings by reducing costs associated with climate-controlled shelters, sample lines, installation, and shipping. The next question to ask is, “What is my environment? Does it allow the use of the more cost-effective shelters?” As discussed, some applications and environments 8 Finding and reducing the “hidden costs” in gas chromatograph installations White Paper preclude the use of a sun shield or a three-sided shelter because the environment demands that operators be protected, or a large amount of instrumentation is being installed on the site. A key point to understand is that even if a full shelter is required, the transmitter-type GC may still be the more cost-effective solution due to its smaller footprint than a traditional process gas chromatograph. The smaller footprint means a smaller size cabinet or walk-in shelter. The smaller size, lower power requirements, and lower utility gas usage make a transmitter-type GC significantly less costly to operate than an air-bath oven GC. Another important benefit to using a field-mountable GC even in an analyzer house is flexibility. There’s always the potential that demands will change. If new environmentally sensitive instruments need to be introduced into the shelter, the field-mountable GC can be moved out into a simple shelter or no shelter at all. Field-mountable instruments give the potential to expand without spending hundreds of thousands of dollars on a new analyzer house. Upgrade projects also benefit from this flexibility, allowing a field-mountable instrument to be added to an existing system without the need for construction of a new enclosure. Space within an existing analyzer house is premium so an upgrade from an air-bath oven GC to a transmitter-style GC can free up space within the shelter due to the smaller footprint of the transmitter-style GC. Existing structures — even those that may no longer have fully operational HVAC systems — can be reused and the demolition of old analyzer houses, and the costly design, purchase and installation of new ones, are avoided. Likewise, field-mountable GCs are fire- and explosion-proof, so they can be moved to hazardous locations as the need arises. Conclusion A decision to add a gas chromatograph in a plant is often the result of extensive research and planning, and the benefits of the GC are well understood. Allowing those informed decisions to be derailed by hidden costs that aren’t considered in the planning phase can scuttle a budget. Knowing to ask if a field-mountable GC can be used in a given application can be the question that opens the door to hundreds of thousands of dollars in savings and provides the flexibility to make the new GC a valuable return on investment for many years to come. 9 White Paper For more information on gas chromatographs or gas analysis systems, visit Emerson.com/RosemountGasAnalysis Linkedin.com/company/Emerson-Automation-Solutions Twitter.com/Rosemount_News Facebook.com/Rosemount Global Headquarters Emerson Automation Solutions 6021 Innovation Blvd. Shakopee, MN 55379, USA +1 800 999 9307 or +1 952 906 8888 +1 952 949 7001 GC.CSC@Emerson.com 00870-0100-3701, Rev AB, June 2019 Youtube.com/user/RosemountMeasurement Emerson Terms and Conditions of Sale are available upon request. The Emerson logo is a trademark and service mark of Emerson Electric Co. Rosemount is a mark of one of the Emerson family of companies. 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