Blowdown control system
April 2006
PLCs, DCSs & Controllers
Because water is such a good solvent, boiler feedwater can contain a high level of dissolved salts and minerals, even if a feedwater treatment plant is installed. Water treatment can chemically modify the form of the dissolved solids, but will not usually remove them completely, and can even increase the total dissolved solids (TDS) level.
As steam is evaporated these dissolved solids are concentrated in the boiler, increasing the TDS level. If the TDS is allowed to get too high then carryover of the boiler water with steam will occur. This can cause serious damage to the steam system through water hammer, corrosion and deposits on heat transfer surfaces. Deposits in control valves and steam traps can build up rapidly, causing operating problems. Product contamination and reduced heat transfer rates may affect productivity.
In order to limit the TDS to the level recommended by the boiler maker, it is normal practice to periodically drain off, (or 'blow down') boiler water and allow it to be replaced by relatively low TDS feedwater. Excessive blowdown is of course very expensive in terms of lost energy and water treatment chemicals.
The Spirax-Sarco BCS3 automatic control system is available with one of three types of controllers to solve these problems. The system minimises the amount of blowdown required, reducing energy and water treatment costs. It also avoids excessively high TDS levels and associated carryover. The BCS3 system is suitable for shell and water tube boilers and can be linked to energy/building management systems. The system provides automatic control of boiler TDS and avoids carryover problems due to high TDS levels. Remote indication of the operating conditions via the high TDS alarm and 0 to 20/4 to 20 mA outputs are offered. Probe cleaning plus compensation for scaling on the CP32 conductivity probe gives accurate TDS control.
The BC3200 is a wall-mounted controller with a four-digit LED display and two pushbuttons for simple commissioning, calibration and operation. It operates on 230 V or 115 V, 50-60 Hz selected by an internal switch. Selectable ranges such as ppm or µS/cm are available to suit all types of boilers.
With the same features as the BC3200, the BC3210 controller has an enclosure for mounting in a boiler panel. The BC3100 is a DIN rail or chassis plate-mounting controller with LED indication of the blowdown status, and potentiometer adjustment of set point, calibration and alarm levels.
For more information contact Richard Ransome, Spirax-Sarco, 011 929 6344, [email protected]
Further reading:
All eyes on the modern DCS platform
Schneider Electric South Africa
PLCs, DCSs & Controllers
Modernised DCS platforms are no longer confined to hardware-dependent architectures. These systems have evolved to combine the strengths of both PLCs and DCS while adding capabilities that make them more open, resilient and collaborative.
Read more...
Automation solution for waste management at incineration facility
PLCs, DCSs & Controllers
Valmet is to deliver an automation system to Seongnam City’s incineration facility currently under construction in South Korea. By leveraging intelligent automation, the plant will optimise energy production, minimise emissions and deliver efficient, consistent performance throughout its entire lifecycle.
Read more...
Valmet’s supplies DCS to Europe’s largest electric boiler plant
Valmet South Africa
PLCs, DCSs & Controllers
Valmet will supply an automation system to Helen’s Hanasaari electric boiler plant and a thermal accumulator being built in Helsinki, Finland. Once completed, it will be Europe’s largest electric boiler plant.
Read more...
Technology blueprint paves way for e-methanol fuel expansion
Schneider Electric South Africa
PLCs, DCSs & Controllers
Schneider Electric has delivered the technology stack behind European Energy’s Kassø Power-to-Xfacility, the world’s first commercially viable e-methanol plant.
Read more...
PCS Global delivers turnkey MCC installation in Botswana
PCS Global
Editor's Choice PLCs, DCSs & Controllers
PCS Global is delivering a turnkey containerised MCC installation for a major copper mining operation in Northwest Botswana.
Read more...
New energy-efficient evaporation line for dissolving pulp production
Valmet South Africa
PLCs, DCSs & Controllers
Valmet will deliver a new evaporation line to Altri Biotek mill in Portugal. This delivery is part of Altri’s €75 million project to convert the Biotek mill to produce dissolving pulp for the textile industry.
Read more...
Valmet modernises turbine automation
Valmet South Africa
PLCs, DCSs & Controllers
Valmet has received an order to deliver a comprehensive replacement of plant DCS and turbine control systems at Ennatuurlijk’s combined cycle power plant in the Netherlands.
Read more...
Hybrid DCS for an evolving industrial landscape
Schneider Electric South Africa
PLCs, DCSs & Controllers
Today’s industrial automation continues to evolve at a blistering speed, which means traditional DCSs have to keep up to ensure continuous integration into modern, digital infrastructure.
Read more...
IIoT controller for the field and control cabinet
ifm - South Africa
PLCs, DCSs & Controllers
The IIoT controller from ifm is a powerful, communicative and flexible PLC solution in machine and plant digitalisation.
Read more...
Bringing the benefits of Ethernet to hazardous industrial environments
ABB South Africa
PLCs, DCSs & Controllers
Christian Johansson, global product manager for ABB Process Automation explains how Ethernet-APL lets plant owners unlock more value from their process data, optimise performance and promote safer operations.
Read more...
printer friendly version