Case Study :

Leaders in automation & real-time IT

Allied Distillers Gas Fired BoilerControl System Refurbishment

Power Generation

Allied Distillers (now owned by ChivasBrothers) distils, blends, bottles and exportsScotch Whiskies, Gin, Rums and Liqueurs to150 countries worldwide.

One such distillery owned and operated byAllied is the Strathclyde Distillery located in thecentre of Glasgow, which process Grain andMalted Barley to produce Grain Whisky andGrain Neutral Spirit, together with an associatedby-products plant producing Animal Feed.

This plant has its own natural gas (or HFO) firedboiler plant that produces steam for the distilleryprocess. The boiler plant comprises twowater-tube natural gas fired boilers (installed in1975) which generate process steam to thecontinuous and batch process plant.

The maximum output of the Boiler Plant is 90,000Kgof steam per hour which is consumed by the distilleryprocess plant. The boilers respond to the steamdemand created by the process that can varyconsiderably during the day in accordance with therequired load profile. A secondary function of the plantis to incinerate waste gases which are produced by the

process.Various options were considered by the client such asa new CHP, or contract management of the plant, buteventually the decision was made to refurbish the plantby fitting a new control, burner management andinstrumentation system comprehensive enough to runas an unmanned boiler plant.

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To achieve this, the client awarded Capula a fullturn-key contract for the full refurbishment of the boilercontrols. The scope of work included the new controlsystem, SCADA system, burner management system,automatic blowdown, variable speed drives, UPScabling, actuators, and instrumentation.

One of the key aspects of the project was the tighttimescales under which the contract was let. Theinstallation had to be carried out during a short plantoutage and the entire job had to be completed in six

months from start to finish.The contract involved extensive field design andinstallation work, both mechanical and electrical. Thisincluded all cabling, installation of the new field devices,mechanical design and fabrication of modified pressurepipe-work, installation of new valves, and so on.

A key feature of Capula's project team was the SiteManager, based on site throughout the installation andcommissioning phase of the project co-ordinating allsite activities which were achieved without incident.

Project Implementation

The new control system was based around dualRockwell ControlLogix PLC systems, dual FireyeBurner Management Systems, and a RockwellRSView32 SCADA. In addition, each boiler requires

accurate speed control of the two forced draft fans andso the old Thyristor drives were replaced by modernRockwell 143 KVA variable speed drives.

The Solution

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The safety critical interlocking of the plant is provided bythe Burner Management Systemwhich is a hardwired/electronic systemwith full diagnostic capability. This wasbased on Fireye equipment and is independent from

the PLC but fully integrated into the control system.The BMS provides themeans of ensuring that all of thenecessary permissives and interlock signals for burnersand combustion plant are safely handled.

Safety Critical

PG_ALLIED_DISTILLERS_GAS_FIRED_BOILER_CSR

For further information, please contact sales@capula.co.uk:

Capula Limited, Orion House, Stone, Staffordshire ST15 0LTT: +44 (0)1785 827000 F: +44 (0)1785 825902 W: www.capula.co.uk

• Reduced operator intervention, such that the plant can be deemed 'unmanned'. This was

achieved through greater automation

• Reduced cost of maintenance & improved reliability of the control system. The previous

control systemwas a pneumatic typewhich had become obsolete, unreliable, and difficult to

maintain

• Optimised boiler fuel efficiency

• Tighter control of the steam quality (i.e. temperature, pressure, flow). This improved

quality control and improved process efficiency

Business Benefits Delivered

Capula were chosen via a competitive tenderprocess because we demonstrated fulltechnical compliance with the specificationalong with the willingness to ensure all relevantsafety and technical standardswere adhered to.

The ability tomobilise a skilled and experiencedteam to deliver the project within ademanding outage related programme wasalso a major factor.

Why Capula?

The new PLC system contains the boiler processcontrol algorithms such as master steam pressurecontrol, boiler drum level, flue gas temperature, DAlevel control, etc. These were tuned to give precisecontrol of the steam pressure under all load conditions.

The control required is more sophisticated than on aconventional gas fired boiler plant due to the effects ofincineration of the waste gases received from theprocess and the very variable steam load.

Process Control

The control system also contains automationsequences to permit a fully automatic start-up andshut-down of the plant, and automation of variousmanual activities such as boiler blowdown, feed watercontrol, and so on.

To achieve the level of automation required, Capulainstalled new actuators and transmitters. In total wefitted: 16 new actuators, 20 new pressure andtemperature switches, 40 new transmitters, 6 newvalves and 6 new analysers.

Automation

The project had to comply with a number of standardssuch as the HSE PM5 and PM60 standards and theSAFed Guidelines. SAFed was particularly importantbecause the new boiler control systemwas required to

automate the boilers to the SAFed arrangement 3which states the safety features required of anunmanned boiler.

Standards Compliance