Showing posts with label thermocouples. Show all posts
Showing posts with label thermocouples. Show all posts

Friday, June 28, 2024

From Production to Transportation: The Role of Thermocouples in the Hydrogen Revolution

The Role of Thermocouples in the Hydrogen Revolution

The global push towards a hydrogen-based economy is gaining momentum as countries invest heavily in this clean energy source worldwide. From production to storage and transportation, hydrogen technology is evolving rapidly, with industrial thermocouples playing a crucial role in ensuring safety and efficiency across the entire value chain.

Hydrogen production methods are diversifying, with green hydrogen leading the charge. Electrolysis, the process of splitting water into hydrogen and oxygen using electricity, requires precise temperature control to maximize efficiency. Industrial thermocouples monitor electrolyte temperatures in alkaline and proton exchange membrane (PEM) electrolyzers, helping operators maintain optimal conditions for hydrogen generation. In high-temperature electrolysis using solid oxide cells, thermocouples become even more critical, measuring temperatures up to 1000°C to prevent cell degradation and ensure longevity.

For blue hydrogen production, where natural gas is reformed and the CO2 is captured, thermocouples are essential in monitoring steam reformer temperatures, often exceeding 800°C. These devices help optimize the reforming process, balancing efficiency, catalyst life, and equipment integrity.

Hydrogen storage presents unique challenges that thermocouples help address. Liquid hydrogen storage must maintain cryogenic temperatures of -253°C. Specialized thermocouples provide accurate readings at these extremely low temperatures, preventing boil-off and ensuring safe storage conditions. For high-pressure gas storage, thermocouples monitor compression heat, helping prevent overheating and potential material embrittlement.

Temperature control is crucial for both charging and discharging processes in metal hydride storage systems, where hydrogen is absorbed into metal alloys. Thermocouples embedded in these storage units help manage the exothermic absorption and endothermic desorption reactions, optimizing storage capacity and release rates.

Hydrogen transportation relies heavily on temperature monitoring for safety and efficiency. In hydrogen pipelines, thermocouples track temperature fluctuations that could indicate leaks or unexpected reactions. Thermocouples continuously monitor insulation effectiveness and overall system integrity for liquid hydrogen transport in cryogenic tanker trucks.

Thermocouples play a vital role in the precooling process at hydrogen refueling stations. As hydrogen is dispensed into vehicles at high pressure, it must be cooled to prevent the vehicle's storage tank from overheating. Thermocouples ensure the hydrogen reaches the correct temperature before dispensing, typically around -40°C.

In fuel cell applications, from vehicles to stationary power systems, thermocouples monitor stack temperatures to prevent hotspots and ensure optimal operating conditions. This is particularly important in proton exchange membrane fuel cells, where water management is critical for efficiency and longevity.

The manufacturing processes for hydrogen equipment also rely heavily on thermocouples. In producing carbon fiber tanks for high-pressure hydrogen storage, thermocouples monitor curing temperatures during the filament winding process, ensuring the structural integrity and safety of the final product.

As hydrogen blending in natural gas networks becomes more common, thermocouples will monitor mixing stations and end-use appliances to maintain safe combustion characteristics despite varying hydrogen concentrations.

In the realm of hydrogen safety, thermocouples serve as early warning systems. In storage facilities and production plants, these devices can detect temperature spikes that might indicate a leak or an unwanted reaction, allowing for rapid response to potential hazards.

The development of hydrogen-powered aircraft represents another frontier where thermocouples will be indispensable. From monitoring cryogenic fuel systems to managing heat in hydrogen combustion turbines, these sensors will be crucial for the safety and efficiency of future zero-emission flights.

As the hydrogen economy expands, we expect increased demand for specialized thermocouples tailored to these applications. Manufacturers are already developing new alloys and designs to withstand the unique conditions of hydrogen infrastructure, from cryogenic temperatures to high-pressure and potentially corrosive environments.

The transition to a hydrogen-based economy offers a path to significant carbon emission reductions across multiple sectors. As countries invest in production capacity, storage solutions, and transportation infrastructure, the role of industrial thermocouples in ensuring the safety and efficiency of these systems becomes increasingly vital. These unassuming yet critical devices will continue to evolve alongside hydrogen technologies, underpinning the temperature monitoring needs of this clean energy revolution and helping to build a more sustainable future.


Wednesday, January 19, 2022

Engine, Turbine and Compressor Thermocouples

Engine, Turbine and Compressor Thermocouples

A lot of electricity is needed to run complicated equipment on offshore oil and gas installations. Some of the things that need power in the drilling and processing area are pumps, valve operators, critical communications, turntables, engines, safety devices, and more. Like that used by a small town, much electricity gets consumed. Heating, air conditioning, water desalination, food storage, and even trash processing all use electricity from electric generators that run on gas or electricity. 

The conditions on offshore sites can be challenging. Equipment and parts must be robust to work correctly and cut down on regular maintenance. 

Temperature is one of the most critical measuring factors in a compressor, and its accuracy directly impacts compressor efficiency. According to the findings, temperature calculation errors account for more than 80% of efficiency errors. More information about compressor temperature measurement, as well as improved temperature measurement methods, are needed. Thermocouples measure the temperature of the interstage gas compressor and the temperature of the exit gas. 

In these cases, a unique temperature sensor called an "engine-compressor thermocouple" is used to measure temperature. These are temperature sensors that can tell you about many things, like how hot the exhaust gases are and how hot the lubricant is. Such sensors have been used for a long time and built to withstand the extreme mechanical and climatic conditions found in offshore maritime environments. If the thermocouple has exposure to a lot of vibration and chemicals, it needs to be durable and accurate at the same time. 

Engine-compressor thermocouples give oil and gas platform workers precise measurements, high precision, and quick responses to changes in the engine's temperature and compressor. As a bonus, engine-compressor thermocouples are easily calibrated, removed, and replaced if needed.

Duro-Sense Corporation

Monday, July 26, 2021

Protecting Against Noise in Thermocouple Installations

Noise in Thermocouple Installations

Thermocouples are widely used to measure temperature because they are durable, affordable, and have a wide temperature range. A thermocouple is formed by the joining of two different metal alloys at a common point referred to as the measuring or hot junction. Thermocouple lead wires attach to a temperature measuring instrument at a second connection point called the reference or cold junction. When the hot junction is heated, the thermocouple generate a very modest DC voltage. The tiny voltage signal is detected by the temperature measuring instrument and converted to a temperature reading. 

Thermocouples produce voltages in the millivolt range, with microvolt changes per degree C temperature change.  The signal (voltage) of a standard thermocouple is low, on the order of 10 mV, and the signal-to-noise ratio can rapidly drop in the presence of the types of electrical noise seen in most industrial situations. A small amount of noise can have a significant impact on precise measurement. 

There are numerous sources of noise that can interfere with thermocouple measurements.  The three most typical sources of noise are as follows: 

Common Mode Noise from Ground Loops  

Common mode noise generates an undesirable voltage on both leads of the thermocouple. Common mode noise is typically induced by a ground loop, which occurs when a system has a potential difference between two grounds. Because the tip of a thermocouple is a bare wire junction, a ground loop might form. If the tip is grounded where it is detecting temperature and that ground is at a different potential than the ground at the thermocouple's measuring end, a ground loop forms and current flows. 

Normal Mode Noise from Electromagnetic Fields  

Normal mode noise generates a current that flows in the opposite direction as the measuring current. This form of noise is often created by massive alternating current current sources, such as power lines, which generate a magnetic field. The magnetic field, in turn, generates a current in the measurement path. Motors, lights, and power lines are examples of high-current devices. Normal mode noise is typically at 50/60 Hz line frequency. The normal mode error current is proportional to the field intensity, the size of the loop, and the loop's orientation to the field. 

Electrostatic Noise from Rotating Equipment

Stray capacitance introduces electrostatic noise into the measuring path. Electrostatic noise is created by rotating equipment, which generates an alternating current (AC) current that is capacitively connected into the measurement route. Electrostatic noise can be coupled by stray capacitance through the tip of a thermocouple. 

The following procedures will significantly reduce thermocouple susceptibility to electrical noise in an industrial setting. 

  • Twist and foil shield the extension or lead wires from the thermocouple to the measurement instrument. Twisting wires together minimizes both outgoing and incoming noise caused by electromagnetic interference. Each wire in the circuit carries voltages that are both equal and diametrically opposed. The voltages on the two lines are the same, but the polarity is reversed. The polarity of the magnetic field formed around the wire is determined by the polarity of the electric voltage going through the wire. Not only is the polarity of the electric voltage on each wire opposite, but so is the polarity of the magnetic fields radiating from each wire. When equal but opposing forces collide, they cancel each other out. 
  • Ground the measurement junction at the point of measurement. The grounding is typically to the inside of the stainless steel sheath that covers the actual thermocouple. The advantage of grounding the measurement junction is that the electrical noise is distributed equally on each wire of the thermocouple.
  • Use a transmitter with excellent common mode voltage rejection and position it as close to the thermocouple as possible.