Bausch + Lomb (B+L), a manufacturer of medical devices and pharmaceutical products located in Waterford city, has recently installed and commissioned a state-of-the-art combined heat and power (CHP) plant. The CHP rated at 3.3MWe supplies 72% of the facility’s electricity and 80% of the site’s thermal requirements. Bausch + Lomb received ISO50001 certification in 2013 due to the successful implementation of a number of energy-reduction projects. These include the installation of light-emitting diode (LED) lighting, variable speed drives (VSDs), energy-efficient chillers and sequentially controlled air compressors, all controlled and monitored by the building management system (BMS) and energy management system (EMS). The next phase of the site’s energy strategy was to install auto-production technology. A number of auto-production technologies were considered such as wind and solar for the site. However, CHP technology was chosen based on its availability and return of investment potential. The chosen size and type of CHP was determined in-house and driven by the plant load demand in terms of electrical and thermal usage. A 3.3MWe gas-reciprocating engine with a combined heat recovery system of a heat recovery steam generator (HRSG) from the exhaust gases and engine cooling water (jacket water) providing 2.2 tonnes of steam and 1.5MW of low-grade heat was selected. This highly sought-after project received the attention of a large number of both locally and internationally based organisations involved in the on-site power generation sector. Following an in-house competitive tendering and detailed technical analysis process the contract was awarded to the Edina Group. Edina was chosen due to the type of engine provided, capabilities in providing similar projects in Ireland and its after-sales service team in Ireland. The commercial value of the project exceeded €3.3 million and has a calculated return of investment of 3.4 years. The engine will generate in excess of 27 million kWhs in electricity, some 18.3 mega tonnes of steam and 12,483MW of low-grade hot water per annum. In addition, the annual carbon savings will be 6,500 tonnes per annum. The engine output is the equivalent of powering 5,980 homes with its electricity needs and 2,105 homes with its heating requirements per annum.

Technical and engine selection

[caption id="attachment_31072" align="alignright" width="300"]Bausch Lomb waterford 1 Engine room and 3.3MWe MWM TCG 2032 V12 engine[/caption] The technical and engine selection was also critical because of the continuous running nature of the CHP over the life cycle of 20 years. Edina was able to offer the 3.3MWe MWM TCG 2032 V12 engine with proven reliability in Ireland and throughout the world. Some of the major technical considerations considered in-house compared with other manufacturers are the availability of a medium-speed engine running at 1,000rpm, resulting in significantly less wear and stress. A short crankshaft due to the V12 arrangement, having fewer cylinders and valves (48) when compared to the nearest rival leading to reduced maintenance intervals and costs (the major overhaul of 80,000 operating hours compared to the nearest rival at 60,000 hours). In addition, the shorter crankshaft allowed the engine and alternator to share the same steel plinth, thus avoiding the need to uncouple the engine at the factory and couple the engine once on site. The project commenced in January 2014, where a comprehensive in-house study was under taken to map the energy profile of the site for one full year, thus ensuring that all of the operational and climate conditions were recorded. Once a detailed load profile was conducted, the size and type of CHP system was selected. In July 2014, a selection process was carried out by B+L to identify suitable on-site power generation companies that had the potential to provide a 3.3MWe gas reciprocating engine for the site. The main selection criteria for the vendors were: did they have a proven track record in the sector? Did they have a similar size engine operational in Ireland? And did they have the sufficient after-sales service infrastructure in place to support the CHP over its lifecycle? By December 2014, B+L had engaged with relevant CHP vendors and the tendering process commenced. Finally, in April 2015, B+L selected the Edina Group to provide the CHP for the site and construction commenced in October 2015. The construction period was seven months, where a state-of-the-art bespoke CHP building was constructed to house the appropriate heat recovery systems, switch rooms and engine room. This bespoke CHP building included innovative design specifications such placing auxiliary equipment on top of the building, constructing an additional pipe bridge specifically for the medium voltage (MV) cables and gas pipe, LED lighting, delivering a lower u-value of the building, maintenance platforms, additional acoustic properties including a cavity wall and, finally, a dedicated viewing platform from which the engine can be viewed without entering the engine room. Commissioning of the CHP was successfully completed in May 2016 that included the electrical, steam and low-grade water tie-ins. The CHP became operational in May 2016.

CHP technology

The system is powered by a 45 tonne 4,150hp V12 engine running at 1,000 revolutions per minute. The engine burns approximately 760m3 of grid-connected natural gas per hour. The engine consists of a liquid cooled, twin turbocharged, heavy-duty four-stroke Otto gas-cycle technology. The engine is controlled centrally with an electric control system, enabling operation of the engine at very low consumption levels and using a low-emission combustion process. Additional technical features are the use of a ‘Miller’ camshaft to enhance burning efficiencies and anti-knocking sensors that protects the pistons and valves. The heat recovery system is broken down into two main components: the HRSG and the jacket water systems. The HRSG manufactured by ICI Caldaie is a three-way pass-over shell and tube boiler fitted with a by-pass that allows the 4700C exhaust gases via two silencers from the engine to flow through the boiler thus producing 2.2 tonnes of steam per hour. The jacket cooling is taken directly from the engine via a 1,523KW plate heat exchanger and is distributed around the site using VSD controlled 45KW pumps in a duty/standby configuration. Finally, electricity is generated at 10.5kV and is fed parallel into the existing 10.5kV system via an embedded generation interface protection (EGIP) panel that synchronises and protects the voltage and frequency to the mains supply. The CHP comes with two separate controller systems: the Inteli Modular Gen-set Controller that is used to control, monitor and protect the CHP to marine-type approval regulation; and the total electronic management (TEM) system that provides full graphical operating software for manual control and visualisation of TEM control units, specifically for gas engines. Both of these control systems offers the latest technology of controlling, monitoring, trending, remote interfacing, archiving, logging and user interface between the CHP and the end users.

Power generation, service and maintenance

[caption id="attachment_31074" align="alignright" width="300"]Bausch Lomb Waterford 2 HRSG room and auxiliary equipment[/caption] The Marelli MJB 800 MB 6 alternator is rated at 4,138KVA @ 1,000rmp and has an efficiency of 97.1%. It is of the standard brushless synchronous type producing a 3ph voltage of 10.5KV @ 50Hz. Generator voltage regulation is provided by a voltage regulator of the brushless three-phase exciter type located in the generator itself that adjusts the current supply to the rotor accordingly. A direct signal is taken from the site’s main kilowatt meter that provides the demand load signal to the CHP to enable electricity to feed forward via the EGIP panel. The EGIP panel is required by ESB Networks to ensure the system is protected from grid faults, protection co-ordination and power quality, to name but a few. Frequency and voltage synchronising and protection via the EGIP panel are also a critical safety parameter of CHP power generation systems. Frequency protection is a two-stage time graded under-frequency and over-frequency protection that allows time-delayed tripping for smaller and larger frequency deviations (under-frequency ≤47.5Hz @ 20s – ≤47.0Hz @ 0.5s and over-frequency ≥52.0Hz @ 20s ≥52.5Hz @ 0.5s). Voltage protection is also a two-stage under-voltage and over-voltage protection that allows time delayed tripping for smaller and larger voltage deviations (under-voltage < 0.87pu @ 2.5s – 0.80pu @ 0.5s and over-voltage >1.10pu @ 1.0s - >1.13pu @ 0.5s). The CHP service and maintenance is covered by a service and maintenance agreement contract between the Bausch + Lomb and the Edina Group. Under this agreement, Edina will perform routine maintenance and breakdown responses for a five-year period. Major service overhauls will occur at 20,000 and 40,000 run hours and minor service interventions occurring every 4,000 run hours. The CHP will be remotely monitored by Edina via its SCADA (supervisory control and data acquisition) systems, which will automatically detect and alert the Edina service desk of any issues on site. As part of this service and maintenance agreement contract, the availability runtime of the engine is 95% (or 8,322 hours) per annum, with either penalty or performance bonuses built into the contract, depending on uptime levels. Independent verification of all the CHP output data in terms of gas usage, electrical output, parasitic loads, steam output, LPHW (low-pressure hot water) output and flow rates is via the site’s comprehensive EMS and BMS, where 15-minute interval data is uploaded automatically to track the CHP performance. The CHP has been in operation since May 2016 and, based on the first two months of data, has exceeded expectations in terms on availability (currently running at 97.2%), steam output (currently production 2.35 tonnes/hr), parasitic loads (averaging < 62KW) and increased CO2 savings (>6,750 tonnes/annum). The combined benefits of these additional savings are an additional €93,500 saving per annum, reducing the return of investment by four months to 3.1 years. During the seven-month construction period, some 22,400 man-hours (averaging 20 construction workers per day) were completed without incident. The project concept, detailed design and project management was conducted in-house by Bausch + Lomb and the Edina Group and was completed within schedule and budget. Creativity and innovation and was also a key aspect of this project between both parties in terms of the bespoke CHP building, efficient HRSG including economiser, metering requirements, controls systems applied and the integration into the current campus infrastructure. Author: Derek O’Connor BSc(HONS) Eng, MSc Eng, MIEI, MIET holds both a Master’s Degree in Building Services Engineering from Brunel University and an Honours Degree in Engineering from the University College Northampton. He has over twenty years’ experience within the engineering sector as an engineer and a qualified electrician in various roles. O’Connor is the facilities engineering and structural manager for Bausch + Lomb Ireland, having joined the company in November 2003. He was the project manager for the CHP project and is the site’s energy champion, having achieved runner-up status in the SEAI national energy awards in 2008 in the ‘large user’ category. He was the team lead in obtaining ISO50001 accreditation for the site in April 2013, the first B+L site worldwide to achieve this.