|Fig.1: Low Flow Cut-off|
One of the most common applications for differential pressure transmitters is flow measurement. A differential pressure transmitter can be placed across many types of primary flow elements like orifice plates, pitot or venturi tubes to measure flow. Primary flow elements create a pressure drop (square root proportional to flow).
Flow proportional output signals from a differential pressure transmitter are possible through integral square root extraction. The square root function of differential pressure has extremely high gain at low flow rates leading to large output changes representing low changes in flow rate at the bottom end of the measurement range. Output signals can become erratic at low flow rates due to high gain. Host control systems can experience difficulty controlling flow rate based on a highly fluctuating input signal from the square root extracted differential pressure. DPharp differential pressure transmitters have some unique signal conditioning features to eliminate instability at low flow rates.
Flow rates above 20% of maximum flow produce a large square root extracted differential pressure signal for a given change in flow rate. Flow rates around 5% of maximum flow produce a small square root extracted differential pressure signal for a given change in flow rate (See Fig.1). High gain in the low flow rate operating area amplifies any inherent noise or changes in flow rate leading to pressure transmitter output instability.
DPharp has a software capability to stabilize output signals at the low end of a flow measurement range minimizing erratic output signals. An integral low cut mode features a user programmable transmitter output and set point to change the output to a linearto- pressure (Linear) or zero (Zero) status. The flow rate set point at which an output transition occurs is programmable from 0 to 20% of full scale flow. Fig.2 shows Linear and Zero output modes set at 5 % low cut mode.
Hysteresis is incorporated into the low cut mode such that when the actual flow rate is equal to the low cut set point that output oscillation will not occur. Hysteresis is fixed at a nominal 1% of full scale flow. Fig.3 details how the hysteresis affects the pressure transmitter output.
Main Features of DPharp
EJA110A Digital Solution
- Best-in-class performance
- ±0.03% Overpressure calibration protection
- ±0.1% per 5 years long term stability
- 100:1 turndown
- ±0.065% accuracy
EJX110A Premium Value
- ±0.1% per 10 years long term stability
- 200:1 turndown
- Best-in-class high accuracy, 0.04%
- Multi-sensing output
- Multi-variable transmitter as EJX family line-up
- Safety as standard (IEC 61508)
Chemical plants rely on continuous and batch production processes, each posing different requirements for a control system. A continuous process calls for a robust and stable control system that will not fail and cause the shutdown of a production line, whereas the emphasis with a batch process is on having a control system that allows great flexibility in making adjustments to formulas, procedures, and the like. Both kinds of systems need to be managed in available quality history of product, and to be able to execute non-routine operations. With its extensive product portfolio, experienced systems engineers, and global sales and service network, Yokogawa has a solution for every plant process.
Onshore unconventional drilling is commonly used in the extraction of oil and natural gas today. There are an increasing number of multi-well pad type drilling programs in most of the active plays. Different drilling technics are used to decrease drilling time, lower environmental impact and to improve initial and estimated ultimate recovery.
Floating Production Storage & Offloading (FPSO)
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Offshore exploration and production requires maximum uptime under harsh conditions. Manned and unmanned facilities need reliable integrated control and safety systems (ICSS) with advanced remote monitoring capabilities. Yokogawa has state-of-the-art technology and extensive experience in executing offshore projects of all sizes and automation levels of complexity.
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Yokogawa has a wealth of experience in every part of the oil and gas business, from offshore and onshore facilities to pipelines, terminals, and deepwater operations. We provide solutions that enhance safety, ensure accurate and reliable operation, and increase plant efficiency.
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The oil & gas downstream industry has been facing an increasing number of challenges in recent years. These include the changing characteristics of the feedstock to be processed, aging of process facilities and equipment, rising cost of energy, lack of skilled plant operators who can run a refinery safely and efficiently, and the ever-changing requirements from both the market and the customer.
Over the years, Yokogawa has partnered with many downstream companies to provide industrial solutions focused on solving these challenges and problems. Yokogawa's VigilantPlant solutions have helped plant owners to achieve maximum profitability and sustainable safety within their plants.
The onshore upstream industry faces ever higher demands and greater challenges with increasingly difficult and hostile environments in which it must operate.
- Diverse needs of petrochemical companies’
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The right pipeline control and instrumentation can make a huge difference in terms of performance and profitability. Yokogawa has dedicated technology that can optimize the performance of all elements of a pipeline solution, including compressors, pumps, valves, and intermediate storage and distribution facilities.
In the mid 1970s, Yokogawa entered the power business with the release of the EBS Electric Control System. Since then, Yokogawa has steadfastly continued with the development of our technologies and capabilities for providing the best services and solutions to our customers worldwide.
Yokogawa has operated the global power solutions network to play a more active role in the dynamic global power market. This has allowed closer teamwork within Yokogawa, bringing together our global resources and industry know-how. Yokogawa's power industry experts work together to bring each customer the solution that best suits their sophisticated requirements.
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In the ever-changing marketplace, refineries are seen not only as crude processing units but also as profit centers. At the same time, there is a keen awareness of the need for safety at such facilities. A total production solution that encompasses planning, scheduling, management, and control is required to achieve long-term goals for profitability, efficiency, and environmental protection. With years of expertise in the automation field, Yokogawa can bring you affordable total solutions for improved operability and a cleaner world.
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Yokogawa has long served customers in the specialty and fine chemicals market. With a market leading batch solution that offers the best in class reliability and flexibility as well as industry experts who understand the complex requirements in designing a batch solution, you can be assured that in your partnership with Yokogawa you will have a system that will enable you to produce products that meet your customers’ needs in the future while maintaining safety and regulatory compliance.
Thermal power using coal, oil or gas as fuel accounts for the majority of electric generation throughout the world.
- Topsides processing and handling on the production platform prep extracted hydrocarbons for transport
- Yokogawa integrated control/monitoring maximize topsides operations productivity and availability
The upstream industry includes offshore and onshore activities including wellhead automation, fractionation, completion, and separation to recover and prepare underground or underwater crude oil and natural gas.
As petroleum is brought to the surface, it must be separated prior to transport. Primary and secondary separation stages commonly distribute gas flow, water flow, and oil flow in three phase separation. Gas movement requires pipeline and can include a fractionation process in the upstream stage prior to movement. Liquids can be placed into a tanks or pipelines and sent for processing, requiring accurate level measurements.
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Water resources are finite, and therefore contributing to a sustainable water cycle is one of the Sustainable Development Goals (SDGs). Yokogawa has been providing advanced digital control solutions for the stable supply of clean and safe water, wastewater treatment for protecting the water environment, water loss management, and optimization of plant operation for reducing CO2 emissions and running costs. Yokogawa works with you to increase your efficiency while ensuring compliance standards …. Smart measuring IA to IA.
Yokogawa provides optimum solutions to improve the reliable operation of water treatment plants. These solutions include sophisticated technologies, unsurpassed product quality, and extensive application know-how throughout the lifecycle.
Wellhead & Separation
The wellhead provides the structural and pressure-containing interface for the drilling and production equipment. The surface pressure control is provided by a christmas tree, which is installed on top of the wellhead. Isolation valves and choke equipment physically control the flow of well fluids when the well goes into production. Various automation packages are added to locally or remotely monitor, control and optimize production from each well or multi-well pad. Oilfield separators employ a pressure vessel to separate well fluids produced from oil and gas wells into gaseous and liquid components which are then transferred to pipelines or localized storage depending on the areas infrastructure.
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