Fertile ground for Jenbacher1 March 2007
CHP installation experience gained by Jenbacher in Europe is proving to be fruitful in the expanding cogeneration market, as the winning of these two contracts, including the first North American application of its CO2 enrichment technology, tends to indicate.
Growing ‘good’ CO2
Commercial tomato greenhouse operator Soave Hydroponics, a division of Michigan-based Soave Enterprises, is installing a special cogeneration plant in its 55 acre Kingsville greenhouse facility in response to Ontario Power Authority’s Request for Proposals to add 1000 MW of cogeneration power capacity to the local grid. The installation is also expected to boost crop production at the company’s facility in the Leamington region on the north shore of Lake Erie, about 350 km west of Toronto.
Construction on the plant is scheduled to start in May and be completed by December 2007, and is one of seven cogeneration projects recently approved by the OPA as it seeks to diversify the region’s energy supply. This cogeneration system features four Jenbacher JMS 620 gas engines as well as the heat recovery, exhaust treatment equipment and noise abatement insulation.
The technology for fertilisation by CO2 enrichment in greenhouses was developed at GE’s Jenbacher ‘Centre of Excellence’ in the Netherlands. Carbon dioxide, of course a key component in the process of photosynthesis, can be recovered from the engines’ exhaust. After purification using catalytic converters, the exhaust gas is cooled down and supplied to the greenhouse crop for CO2 enrichment.
The new plant’s 12 MW of electrical output will be supplied primarily to the Ontario Power Authority, under a 20-year power purchase agreement. The thermal energy from the engines will be stored in hot water tanks and deployed as required to heat the greenhouse.
As a result of installing the special cogeneration system, Soave Hydroponics should be able to reduce its energy costs without curtailing its annual production levels, thus improving its competitive position in the commercial tomato industry.
“The project is an important one for GE Energy, as it represents the first Jenbacher CO2 fertilisation cogeneration system to be installed in North America,” said Prady Iyyanki, ceo of GE’s Jenbacher gas engine business. “While this is a common application in the Netherlands, the Soave ... plant will serve as an important reference project for our customers in North America.”
Distributor DDA Canada East supplied the cogeneration modules. GE Energy is providing balance of plant, project management and plant installation services from the Netherlands. H.H. Angus and Associates Ltd. of Toronto is providing engineering services.
Advanced cycle runs on wood
GE Energy will also to be supplying two CHP units for a new and innovative wood gas project in the town of Oberwart in the Austrian province of Burgenland.
The decision to purchase these particular gas engines came after several years of successful operation of a Jenbacher CHP unit in the nearby town of Güssing, which also is using wood derived gas for power and heat.
GE Energy is supplying two Jenbacher JMS 612 GS-S/N.L engines to Ortner GmbH, which as the main contractor has been commissioned to design and construct the entire plant on behalf of Energie Oberwart Errichtungs-GmbH. Ortner GmbH is responsible for the overall engineering, construction, systems engineering, and instrumentation and control equipment.
The project is scientifically supported by the Vienna University of Technology’s Institute of Chemical Engineering. The plant is expected to be commissioned in November 2007, providing 2 MWe and 6 MWt. The generated heat will be fed into the district heating system operated by Energie Oberwart, supplying heating to the local hospital and yet-to-be-built facilities in the industrial area of Nord. The plant’s power product will be fed into the local public grid.
Part of the electrical power will be obtained from exhaust gas heat using an organic Rankine cycle, or ORC process. The ORC process is based on a cycle similar to the water/steam cycle, but instead of water, it utilises as its working medium an organic fluid, such as a refrigerant like freon, organic compounds such as toluene or butane, or even ammonia solution. Although of inherently lower Carnot efficiency it works well at relatively low temperatures and is commonly applied in, for example, steam generators firing biomass.
A fluidised steam gasifier first converts the wood into a low-tar gas with a calorific value of 2.7 kWh/m3N and a comparatively high hydrogen content (30 - 40 % by volume). The two engines produce power from this gas, while exhaust heat from the engines is sent to the ORC process and district heating exchangers.
The control system, a Jenbacher DIA.NE XT engine management system, is said to react quickly to the characteristic fluctuations in the composition of the wood gas and its varying calorific value, offering precise monitoring of the combustion process in the engine and effective co-ordination of the engine and gasifier.
In recent years, there has been a steady increase in the use of special gases produced by gasification processes for energy supplies, mainly from biogenic raw materials and waste, as well as landfill gases. Gas engines incorporating the latest technology are well suited to the efficient combustion of such gases.
A wood gas plant in the town of Güssing, Austria, powered by a cogeneration system similar to the units being installed at the new wood gas plant in the nearby town of Oberwart.