Power Industry Boiler Water Level Measurement Techniques

The March 2017 Inst Measurement and Control Technical Seminar evening will be hosted by Doosan Babcock in Manor Royal, Crawley, on Tuesday 21st March 2017.

This will be a tri-company, collaborative event, presented by Doosan Babcock, and also featuring contributions from Vega and TC-Fluid Control. It is aimed at providing attendees with a useful insight into industrial measurement application challenges in order to further their professional development knowledge.

Drum Level Control

The first presentation by Doosan Babcock will discuss Drum level measurement using DP Measurement and Hydrastep Measurement techniques.

Power station Steam Drum Level measurement is required for drum level control, Burner Management System (BMS) protection and Code compliance. Drum level is both a critical and difficult measurement to make. At steady state conditions, considerable turbulence in the drum can cause the level to fluctuate. A changing rate of water inflow and steam outflow adds to the potential for measurement error. The DP Measurement technique uses the difference in pressure between a head of water in an external reference column and the level in the drum. The density of water and steam vary appreciably with pressure, so the differential pressure obtained at any given level will vary as boiler pressure changes.

The Hydrastep technique detects the conductivity variation between the steam and the water. The electrode principle is an efficient system for measuring drum water levels.

Microwave Technology

Vega will explain how microwave technology can tackle a wide variety of applications associated with steam boilers. Non-contact or guided wave techniques have the ability to measure reliably, even with fluctuating temperatures up to 450C combined with pressures of up to 400 bar. Measurement is virtually unaffected by pressure and temperature changes. Top mounting makes installation and maintenance easy. In many cases microwave transmitters provide an alternative to legacy equipment for both solids and liquids. SIL qualification and boiler approval now enables microwave technology to  be used directly on steam boilers, with special modifications to compensate for saturated steam effects.

Visual/Glass and Boiler Steam Glass level gauges

untitledVisual/Glass and Boiler Steam Glass level gauges are a requirement on steam boilers for visual verification of the level control system, and will be discussed by TC-Fluid Control. Magnetic level gauges have many applications on and around the boiler, providing visual level indication whilst minimising potential leak paths, and can be used as an alternative to one of the glass level gauges on the boiler drum. Simple, robust technology provides a highly visible indication of process level at pressures of up to 400 bar and temperatures up to 450C.

Postscript: Wessex IMC Section meeting

Vega Controls will also give a talk to the IMC Wessex Section meeting on 15th March about the technology behind their 80GHz radar liquid level measurement systems. The talk will include live demonstrations, and takes place at the Forest Lodge Hotel, at Lyndhurst. A video is available that shows their new sensor.

 

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The Yokogawa User Group conference in Budapest

The “User Group” conferences, which provide a meeting place for automation and control managers and engineers from different companies and industries to meet and share their operational experience, started in the USA, and have blossomed in Europe in the last few years. Usually hosted by a major supplier, they encourage their clients to come together in a way that is more cost effective, for them, than a standard commercial exhibition and conference. But they always gather their normal specialist sub-suppliers as partners, to also show and talk about their products, and explain how they can interface together to create a total plant system, in the mini-exhibition running alongside meal and coffee breaks.

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The conference dinner was held in the Hungarian National Gallery, by the side of the Danube 

The Yokogawa European User Group meeting took place this May in Budapest. It attracted around 200 engineers and interested editors from all around Europe: from Spain to Norway, from the UK to Turkey, to hear about recent new applications, and the latest product developments.

 

“Transformation 2017” is the current Yokogawa business plan, covering the three years from 2015-17: the year 2015 also happened to be the 100th year since the foundation of the company. So their anniversary year plan focuses on customer interfacing and “Co-Innovation”, which was the main conference theme for the presentations.

Yokogawa appears to have developed a different approach recently, and have become keen to bring in ideas, products and even make acquisitions to broaden their expertise base. They did this previously, but there is a greater emphasis now, it seems. They are also the ISA100 wireless sensor technology leader, amongst the main automation companies, and are helping more small sensor manufacturers to develop this capability.

Wireless sensors to ISA100

Yokogawa have produced wireless versions of their own temperature and pressure transmitters, as you would expect, plus have the routers and base stations necessary to complete the site system. More interesting, they have developed a wireless module, which can be integrated with other (third party supplier) sensors, to create a new wireless measurement sensor. They also have a battery pack that can be exchanged in a hazardous area, when needed, often only after ten years, but maybe after two years if that battery also powers a third party sensor and needs a fast data response time.

In a presentation about a Richter Gedeon Group pharmaceutical plant in Romania, Yokogawa described a wireless sensor installation that monitored the groundwater levels around the site, in 20 wells over an area 1500m x 600m, with some wells actually outside the factory fence. The historic weekly manual monitoring was not felt to be sufficiently frequent, and current environmental standards required an improvement, to at least 4 times a day. Standard HART submersible pressure sensors were used for the level measurement, powered by the battery pack in the Yokogawa wireless module, which communicated digitally with the sensors and then sent the data over ISA100 links. This provides hourly reporting data from each well, and allows the sensor to be put into sleep mode between readings.

The large area of the site, the topography and pipe bridges, provided a challenge for the wireless links. To achieve the transmission distances involved, Yokogawa planned the site layout with four of their independent wireless Routers, to gather data from the local sensors at the extreme distances, and then use the superior range achievable from the Router to the base station to deliver the data. This was then displayed by the pre-existing site ABB 800XA control system, to present any alarm data to the operators, and archive the records.

The IIOT and “Sushi Sensors”

Yokogawa say they have been working on the development of low-cost, small, battery operated wireless sensors, perhaps aptly named as “Sushi Sensors”, for ten years, as well as learning what associated data analysis is required to come to a meaningful conclusion about what the data – “Big Data” – is saying. So it was good to see their Sushi sensors on display, in different colours (as you might expect: blue, yellow/gold, and silver) – all with a little stub aerial. But turn these little bugs over and there was an empty shell – nothing there yet! Nevertheless, the work is going on, initially to produce temperature sensor systems: watch that space.

On other stands the GasSecure GS01 hydrocarbon gas detector was on show, which is another ISA100 wireless sensor from Dräger, marketed by Yokogawa for LNG and oil and gas facilities.

STAPS

Spirax Sarco STAPS

Next, Spirax Sarco presented their latest wireless sensor, used for monitoring steam traps on petrochemical plants. Available only recently, from March 2016, this sensor uses the standard ISA100 system, and is called STAPS (which stands for Spirax Total Acoustic Performance Solutions). The acoustic sensing uses a PZT sensor clamped to the outside of the steam line, alongside the trap, and can indicate when the trap is blocked, and when it has failed open, and is leaking live steam. Not only does the STAPS sensor calculate and transmit the rate of steam loss, so the operator can assess the cost and therefore the urgency needed to make a repair, it can analyse the actual type of trap failure. This is done within the sensor electronics, by measuring the emitted acoustic signatures in multiple bands between 5 and 40kHz, to suggest whether the problem is dirt, or a sticky valve, or a damaged valve seat. The STAPS sensor is available intrinsically safe, for petrochemical applications: Spirax previously offered a different wireless sensor for standard industrial plants and boiler rooms, which used a Zigbee communications link.

Customer software and Co-Innovation

There have been two Yokogawa acquisitions in the field of ‘management’ software, which are focused on making the computer based control systems supplied by Yokogawa for plant and process control provide the overview data required by management, improving the connectivity between plant and office, and optimising business operations. First they acquired Industrial Evolution Inc, in January 2016, who provide cloud-based plant data sharing services, or DaaS (Data-as-a-Service). Yokogawa renamed this business Industrial Knowledge: this service has been used in a broad variety of applications such as the sharing of data on oil and gas field operations among authorized users at multiple companies, and the real-time sharing of data with investors on facilities that are operated by third parties. For example when an oilfield is jointly owned by three oil companies, but only one of them acts as the main operator.

Then in April Yokogawa acquired KBC Technologies, a successful provider of software and consultancy focused on achieving operational excellence and improving profitability for both the upstream (oil production) and downstream (oil refineries and petrochemicals production) segments – advanced software for process optimisation and simulation. Originating with three process engineers who started life at the Exxon Fawley refinery, KBC also now incorporates the original Honeywell HPS reactor technology expertise, acquired in 1998, and the chemicals processing technology developed at Infochem, acquired in 2012.

Combining KBC and Industrial Evolution into their Industrial Knowledge business, Yokogawa is expanding its advanced solutions service business by engaging with its customers in a co-innovation process, to add value, using company-wide optimisation of the business operations.

Co-innovation with the specialists

Oil fiscal metering using specialist skids at oil tanker batch shipping terminals is a major application area for Coriolis meters. Yokogawa have just upgraded their Coriolis product line to improve their performance, using modern electronics and sensor technology. The pressure drop for a given flow rate has been greatly reduced, and on-site accuracy enhanced to meet the laboratory tested specifications. Also tube condition monitoring enables on-site checks to confirm that the process conditions have not affected the measurement tubes.

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M+F skids in use at a tanker terminal

Unlike other Coriolis suppliers, Yokogawa do not offer an in-house fiscal metering skid production facility, but rely on the knowledge of their specialist customers to achieve the total package offer. So via their chosen skid supplier customer, M+F Technologies of Hamburg, they have supplied meters for terminal management systems, tank truck loading systems, aircraft and ship supply across the world. The M+F MFX4 batch flow computer has been supplied for blending, leak detection and terminal operations in Latin America, Russia, EU, and Cuba. The latest Yokogawa Coriolis meters, the TI product range, has enabled M+F to reduce the size of the gas separators involved, reducing the skid footprint, and also M+F have reduced the maintenance costs associated. Using TCP/IP communications the system has 24/7 remote maintenance available, essential for 24 hour terminal operations.

Conclusion

The two or three conference days crammed in a lot more than was described above: the delegate just chooses the topics of major interest on his plant. Further announcements showed that Yokogawa is to now construct complete Analyser house systems in Spain, in addition to their existing facilities in Singapore and USA, to serve the European market primarily. Here they act as the site systems supplier, perhaps in contrast to their approach to fiscal metering described above. Yokogawa are also collaborating with Cisco Systems over the Shell SecurePlant initiative, which is to be rolled out over 50 Shell plants, and have developed an interesting collaboration with StatOil, to use wireless sensors to monitor the on-site sound noise level on offshore oil platforms, to ensure personnel safety and monitoring.

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An Analyser house supplied by Yokogawa

The next Yokogawa User Group meeting will be in South Africa in October, for three days in Johannesburg, which should be well worth attending.

Bürkert offer free steam training course

The next session of steam training for 2015 is being held on Wednesday 11th & Thursday 12th November 2015.

In addition to an outstanding, proven technical seminar, enjoy Bürkert hospitality with delicious lunches and a Bürkert goodie bag. This is a great networking event which attracts consultants and end users associated with steam applications.

The two-day course provides theory based learning, backed up with practical applications, for a hands-on approach. Bürkert uses examples and case study materials throughout the courses to highlight typical applications.

The course will cover the following topics amongst many other subjects:

  • Steam fundamentals
  • Steam as a heat transfer media
  • Heat exchange applications
  • Steam piping and condensate loop design
  • Best practices for new and legacy systems 
  • Saving steam and green initiatives
  • Communications protocols
  • Control valve selection and comparison
  • Steam control loops
  • Steam solutions & safety considerations
  • Steam FAQ & troubleshooting
  • Steam sampling systems; pure or culinary steam

One of the reasons we decided not to charge for training is that it removes a barrier to people attending. Delegates’ expectations are more than surpassed after each course.

New Krohne ultrasonic flowmeter for superheated steam

With the Optisonic 8300, Krohne presents a dedicated ultrasonic flowmeter for the measurement of superheated steam. The 2-beam flowmeter stands out with a measuring accuracy of 1%, high repeatability, and a large dynamic measuring range. Typical applications include boiler and plant efficiency monitoring in power plants, energy balancing or inter-company steam billing.

As downtime of steam pipes is very costly and must be avoided, Optisonic 8300 was built for long term use: it features a full bore flow sensor without moving parts or obstructions, and an overall sturdy and robust construction with no cables or sensitive parts exposed. Therefore, it can uphold its measuring accuracy without maintenance or subsequent calibration for up to 20 years, while keeping operating costs at a minimum. If verification of the measuring accuracy should become necessary, it can be provided by using the flowmeter diagnostics, without removing the flowmeter.

With nominal sizes ranging from DN 100 to 1000, or 4” to 40″, Optisonic 8300 is particularly suited to high flow rates. Pressure rating up to 200 bar (3625 psi) and temperature rating up to 540°C / 1004°F are available, higher requirements can be considered on request. With temperature and pressure sensors also connected to the device, the integrated flow computer can calculate steam mass flow.

Optisonic 8300 adds to the Krohne portfolio of ultrasonic process and custody transfer meters for liquids and gases, which now cover the range from compressed air to cryogenic liquid natural gas (LNG).