Saturday, September 30, 2017

HAWK Fibre Optic System (FOS) Pipeline Leak Detection

New pipeline leak detection via infield fiber optic cable.


A new Fibre Optic-based Pipeline Leak Detection System informs of a leak occurrence and also provides accurate location of any potential leakage.

Multivariable single Fibre Optic System sensing detects change in stress / strain due to pipe bending or loss of support. It notes temperature changes caused by liquid or gas movement in pipe leaks. There is also sound and vibration detection from pipe leaks or third-party intrusions.

Systems combine multiple measured variables within one cable, such as sound, temperature, and vibration - to automatically cross reference and remove false signals.

The FOS-based solution seamlessly integrates into an existing digital control system or SCADA to alert operators through a variety of digital protocols.

Introduction to Industrial Continuous Level Control

magnetic level gauge
Magnetic level
gauge combines
float technology
with level gauge
simplicity
(Hawk).
Many industrial processes require the accurate measurement of fluid or solid (powder, granule, etc.) height within a vessel. Some process vessels hold a stratified combination of fluids, naturally separated into different layers by virtue of differing densities, where the height of the interface point between liquid layers is of interest.

A wide variety of technologies exist to measure the level of substances in a vessel, each exploiting a different principle of physics. This chapter explores the major level-measurement technologies in current use.

Level gauges

Level gauges are perhaps the simplest indicating instrument for liquid level in a vessel. They are often found in industrial level-measurement applications, even when another level-measuring instrument is present, to serve as a direct indicator for an operator to monitor in case there is doubt about the accuracy of the other instrument.

Float

Perhaps the simplest form of solid or liquid level measurement is with a float: a device that rides on the surface of the fluid or solid within the storage vessel. The float itself must be of substantially lesser density than the substance of interest, and it must not corrode or otherwise react with the substance.

Hydrostatic level
Hydrostatic level instrument to tank
wall mounting (Yokogawa).
Hydrostatic pressure

A vertical column of fluid generates a pressure at the bottom of the column owing to the action of gravity on that fluid. The greater the vertical height of the fluid, the greater the pressure, all other factors being equal. This principle allows us to infer the level (height) of liquid in a vessel by pressure measurement.

Displacement

Displacer level instruments exploit Archimedes’ Principle to detect liquid level by continuously measuring the weight of an object (called the displacer) immersed in the process liquid. As liquid level increases, the displacer experiences a greater buoyant force, making it appear lighter to the sensing instrument, which interprets the loss of weight as an increase in level and transmits a proportional output signal.

Echo

Radar level
Radar level transmitter (Hawk).
A completely different way of measuring liquid level in vessels is to bounce a traveling wave off the surface of the liquid – typically from a location at the top of the vessel – using the time-of-flight for the waves as an indicator of distance, and therefore an indicator of liquid height inside the vessel. Echo-based level instruments enjoy the distinct advantage of immunity to changes in liquid density, a factor crucial to the accurate calibration of hydrostatic and displacement level instruments. In this regard, they are quite comparable with float-based level measurement systems. Liquid-liquid interfaces may also be measured with some types of echo-based level instruments, most commonly guided-wave radar. The single most important factor to the accuracy of any echo-based level instrument is the speed at which the wave travels en route to the liquid surface and back. This wave propagation speed is as fundamental to the accuracy of an echo instrument as liquid density is to the accuracy of a hydrostatic or displacer instrument.

Weight

Weight level
Level can be determined by
weight using load cells (BLH).
Weight-based level instruments sense process level in a vessel by directly measuring the weight of the vessel. If the vessel’s empty weight (tare weight) is known, process weight becomes a simple calculation of total weight minus tare weight. Obviously, weight-based level sensors can measure both liquid and solid materials, and they have the benefit of providing inherently linear mass storage measurement. Load cells (strain gauges bonded to a steel element of precisely known modulus) are typically the primary sensing element of choice for detecting vessel weight. As the vessel’s weight changes, the load cells compress or relax on a microscopic scale, causing the strain gauges inside to change resistance. These small changes in electrical resistance become a direct indication of vessel weight.

Capacitive

Capacitive level instruments measure electrical capacitance of a conductive rod inserted vertically into a process vessel. As process level increases, capacitance increases between the rod and the vessel walls, causing the instrument to output a greater signal. Capacitive level probes come in two basic varieties: one for conductive liquids and one for non- conductive liquids. If the liquid in the vessel is conductive, it cannot be used as the dielectric (insulating) medium of a capacitor. Consequently, capacitive level probes designed for conductive liquids are coated with plastic or some other dielectric substance, so the metal probe forms one plate of the capacitor and the conductive liquid forms the other.

Radiation

Certain types of nuclear radiation easily penetrates the walls of industrial vessels, but is attenuated by traveling through the bulk of material stored within those vessels. By placing a radioactive source on one side of the vessel and measuring the radiation reaching the other side of the vessel, an approximate indication of level within that vessel may be obtained. Other types of radiation are scattered by process material in vessels, which means the level of process material may be sensed by sending radiation into the vessel through one wall and measuring back-scattered radiation returning through the same wall.

Power Specialties Sales Engineers are experts in industrial level control. Feel free to contact them at (816) 353-6550, or by visiting http://www.powerspecialties.com, for any level application.  They'll assure you get the best continuous level control for the application.

Content above abstracted from “Lessons In Industrial Instrumentation”
by Tony R. Kupholdt under the terms and conditions of the
Creative Commons Attribution 4.0 International Public License.

Monday, September 11, 2017

How Biofuels Are Produced

From biomass to biofuels
From biomass to biofuels
Biomass resources run the gamut from corn kernels to corn stalks, from soybean and canola oils to animal fats, from prairie grasses to hardwoods, and even include algae.

In the long run, we will need diverse technologies to make use of these different energy sources. Some technologies are already developed; others will be. Today, the most common technologies involve biochemical, chemical, and thermochemical conversion processes.

Ethanol, today’s largest volume biofuel, is produced through a biochemical conversion process. In this process, yeasts ferment sugar from starch and sugar crops into ethanol. Most of today’s ethanol is produced from cornstarch or sugarcane. But biochemical conversion techniques can also make use of more abundant “cellulosic” biomass sources such as grasses, trees, and agricultural residues.

Researchers develop processes that use heat, pressure, chemicals, and enzymes to unlock the sugars in cellulosic biomass. The sugars are then fermented to ethanol, typically by using genetically engineered micro- organisms. Cellulosic ethanol is the leading candidate for replacing a large portion of U.S. petroleum use.

A much simpler chemical process is used to produce biodiesel. Today’s biodiesel facilities start with vegetable oils, seed oils, or animal fats and react them with methanol or ethanol in the presence of a catalyst. In addition, genetic engineering work has produced algae with a high lipid content that can be used as another source of biodiesel.

Algae are a form of biomass which could substantially increase our nation’s ability to produce domestic biofuels. Algae and plants can serve as a natural source of oil, which conventional petroleum refineries can convert into jet fuel or diesel fuel—a product known as “green diesel.”

Researchers also explore and develop thermochemical processes for converting biomass to liquid fuels. One such process is pyrolysis, which decomposes biomass by heating it in the absence of air. This produces an oil-like liquid that can be burned like fuel oil or re ned into chemicals and fuels, such as “green gasoline.” Thermochemical processes can also be used to pretreat biomass for conversion to biofuels.

Another thermochemical process is gasification. In this process, heat and a limited amount of oxygen are used to convert biomass into a hot synthesis gas. This “syngas” can be combusted and used to produce electricity in a gas turbine or converted to hydrocarbons, alcohols, ethers, or chemical products. In this process, biomass gasifiers can work side by side with fossil fuel gasifiers for greater flexibility and lower net greenhouse gas emissions.

In the future, biomass-derived components such as carbohydrates, lignins, and triglycerides might also be converted to hydrocarbon fuels. Such fuels can be used in heavy-duty vehicles, jet engines, and other applications that need fuels with higher energy densities than those of ethanol or biodiesel.

Friday, September 8, 2017

Process Control Experts - Power Specialties, Inc.

Established in 1967, Power Specialties was founded on the concept that customer service is of primary importance. Our staff of Sales Engineers are well trained in the application and selection of instrumentation and control products. Specializing in providing instrumentation and control solutions for industry:
  • Ethanol / BioFuel
  • Agricultural and Specialty Chemical
  • Power
  • Pharmaceutical
  • Manufacturing
  • Oil and Gas Production

Visit http://www.powerspecialties.com or call (816) 353-6550.