Low Carbon Combustion Centre
The Low Carbon Combustion Centre, an initiative by the University of Sheffield, is Europe’s leading facility for novel combustion and low carbon technology.
LCCC is committed to providing industry with expert research into power, fuel, energy efficiency and, ultimately, the reduction in carbon emissions.
The centre is equipped to conduct pilot scale research into alternative fuels for the aviation, process, energy and power generation industries.
The development of renewable fuels as an alternative fuel source is a key strategy in reducing the environmental impact of these industries. Therefore the main focus of our work is to provide the expertise necessary to control the combustion processes of these and new low carbon fuels, reduce undesirable emissions and to develop carbon reduction techniques around the use of hydrocarbon fuels.
The unique feature of the site lies in the use of the pilot scale facilities which helps reduce risk for industry. Hence the facilities attract industrial projects as well as more fundamental grant based research.
The Low Carbon Combustion Centre (LCCC) based in Beighton is an initiative by the University of Sheffield.
The centre boasts state-of-the-art facilities with a range of pilot scale test rigs including, a 350 kW fluidised bed combustor, a 60kW Rolls Royce gas turbine engine facility, a 250kW Rotary kiln, a solid oxide fuel cell (SOFC) test rig, a 250kW furnace, an atmospheric combustion and ignition line and a mobile emissions laboratory.
The Centre also houses the Aviation Fuels Thermal Stability Test Unit (AFTSTU) and lubricants stability (LSIS) test rig.
Other than the LCCC, only the U.S. military can facilitate this type of fuel testing. The LCCC is renowned for its world-class research and has been recognised as being the leading research group in the field of alternative fuel, carbon capture and energy. Currently, the centre comprises over 100 members.
The ever increasing stringent regulation in environmental regulation coupled with the increasing need to reduce reliance on fossil fuels has driven much of the group´s research activity since its inception.
Gas turbine engine manufacturer and aviation fuel suppliers such as Rolls Royce and Shell have funded much of the group´s research aimed at improving the efficiency of the aviation gas turbine engine and to seek possible alternative fuels.
The centre also houses a few test rigs which are utilised for solid fuel testing. The combined expertise of both Sheffield and Leeds has allowed research to be carried even in the field of renewable and alternative solid fuels.
In order to reduce dependencies on coal and energy crops, the centre possesses various equipment which would allow blends of multiple biomass and other solid material to be tested while the mobile laboratory is equipped with a state of the art emissions monitoring equipment. Since its establishment, the LCCC has consistently attracted funding from various sources worldwide and continues to grow.
- Aviation Fuels Thermal Stability Test Unit
The thermal stability of fuels is a key concern for the aviation sector and testing at a range of scales in line with fuel availability is crucial to being able to assess the interaction between fuel and fuel system hardware economically.
The LCCC has a unique mix of experimental and modelling techniques at a range of scales which are essential for assessing thermal stability issues. The Aviation Fuel Thermal Stability Test Rig (AFTSTU) is a simulated system, requiring around 7000 litres of fuel per test. This scale allows the testing of real engine events using real engine components such as filters and feed arms.
One of only three similar rigs in the world, the others being owned by the USAF and US Navy, the AFTSTU rig offers a TRL (Technology Readiness Level) 5 testing of the fuel and fuel system for an aviation gas turbine under engine representative thermal loadings up to the point of fuel atomisation.
The rig provides information for engine manufacturers on the performance of new fuel system builds, fuel producers on the performance of alternative fuels, fuel blends or additive packages, all without the cost and risk of a full engine testbed run.
The rig has been used for various test programmes including European alternative fuels programme (ALFABIRD), European engine development programme (TECCAE) and in collaboration with various companies including Rolls Royce, Shell, BP, Sasol and QER.
The rig can be used to study improvements in engine components, new thermal operating conditions, system interaction between fuel and fuel components and the effect of fuel thermal stability additives.
- Gas Turbine Facilities (Auxiliary Power Unit)
The facilities currently have two gas turbines (Auxiliary Power Unit). Details of both gas turbines are listed on this page.
Honeywell GTCP85 Auxiliary Power Unit
The test bed gas turbine engine is a re-commissioned Honeywell GTCP85 Auxiliary Power Unit (APU). The engine test bed facility provides an ideal experimental platform to evaluate the performance of different alternative and conventional fuels on a modern gas turbine engine.
The rig fits in the range of possible combustion analysis between laboratory bench scale testing of fuels, of the order of a litre of fuel, and full engine tests, requiring 1,000s of litres. This has advantages in sourcing sufficient quantities of fuel for testing and the possibility of running several fuels back to back, through one test engine.
The APU is housed in a test room at the Low Carbon Combustion Centre of The University of Sheffield, with an air inlet and exhaust duct system because of operational noise and safety concerns. The engine is located in the centre of the test chamber with the engine control panel, data logging computer, fuel system and exhaust sample lines located outside the laboratory.
The APU could be controlled to run at various power settings. A data acquisition system is used to log a complete set of engine operating parameters.
The following are general specifications for the APU:
- Bleed airflow: 58 kg/min @ 220 °C exhaust gas temperature (EGT) and 0 kW shaft work,
- Maximum shaft work: 149.2 kW
The unit has been configured so that it can run on a variety of fuels and recently it has been used for the Federal Aviation Authority (FAA) funded CLEEN project. This has advantages in sourcing sufficient quantities of fuel for testing and the possibility of running several fuels back to back, through one test engine.
Additionally, APUs are one of the principal sources of particulate matter emissions at airports, results generated on this test bed can be compared with a range of fuels already tested and can be used to assess the improvement in PM (Particulate Matter) emission possible with alternative fuels.
Rolls Royce Artouste
A small Rolls Royce Artouste Auxiliary Power unit (APU) is an integral part of our Gas Turbine Engine Facility and has been utilised for alternative fuel evaluation, and is sited in its own sound-isolated area.
This unit will be able to be externally controlled and monitored from the main University. The engine is rated at 60kW and has a capability of delivering 1.25kg/s of compressed air.
The unit has been configured so that it can run on a variety of fuels. Future work will see it developed to be powered by fuel produced by the gasification plant available within the centre. Details about one of the research work could be found in poster by following the link.
- Atmospheric Combustion and Ignition Line
Two lines are available for the development and testing of burners and ignition units, for such applications as power generation, etc. These lines are capable of supplying air at mass flows of up to 1.5 kg/sec at ambient temperature and pressure.
The line is capable of operating at both ambient and elevated temperatures, being recently been fitted with 120kW electric air preheater which will enable it to operate at temperatures of up to 550K. The lines are able to be operated with a variety of fuels – gaseous, liquid and bio-fuels.
- High Reynolds Number Thermal Stability (HiReTS) Tester
Small scale thermal stability assessment on the basis of a single test method is difficult and several methods should be used together, particularly when assessing a novel product for the jet market.
In addition to the standard JFTOT (Jet Fuel Thermal Oxidation Test) methods, the LCCC also operates the HiReTS (High Reynolds Number Thermal Stability Tester) method is an adaptable small scale research rig, capable of quickly and quantitatively assessing the thermal stability of aviation fuels, under turbulent conditions.
Originally designed by Shell Global Solutions (UK), The HiReTS Tester at The Low Carbon Combustion Centre (LCCC) has recently been employed to provide results for Rolls-Royce plc, Shell Global Solutions (UK) and the European SWAFEA program.
Furthermore, thanks to its unique control system, designed at the LCCC, a wide range of non-standard test parameters can also be employed in order to evaluate the thermal stability of alternative fuel blends, synthetic fuels and fuel additives, under varying degrees of severity.
This is being utilised at the LCCC in order to correlate HiReTS results with much larger tests conducted by our Aviation Fuels Thermal Stability Test Unit (AFTSTU).
- Lubricant System Interaction Simulator
The assessment of lubricant ageing has been traditionally carried out with short duration bench scale tests where a small amount of lubricant is exposed to temperatures that are higher than gas turbine operating conditions to promote accelerated degradation.
This type of testing results in chemical compositions that do not correlate with in-service lubricant samples. A more reliable method for such testing is to use testbed engines, but the significantly higher operating costs and limited time durations do not allow representative ageing tests where the chemical composition of the ageing lubricant can reach equilibrium.
There is a need for a test method that lies between bench scale and testbed engines, which can allow cost-effective testing in an environment that is closely matched to that of aviation gas turbines.
The LSIS (Lubricant System Interaction Simulator) was designed and built by Rolls-Royce plc and it is a unique test facility that addresses all these issues. It is now situated in the Department of Mechanical Engineering at the University of Sheffield UK, and is a part of the LCCC.
The LSIS is based on a modular design concept where components can be added in series or parallel to a main flow circuit so that the different components of a gas turbine can be simulated.
In this way, realistic lubricant degradation conditions can be achieved towards the investigation of the interactions between single or multiple components of a gas turbine and the lubricant itself.
Furthermore, accurate control of parameters such as temperature, heating input and flow rates can be accurately controlled resulting in a facility that can run for thousands of hours with minimal user supervision.
Seal compatibility with fuel, fuel blends and lubricants is an important part of any fuel fit for purpose assessment.
Using rigs developed at the LCCC, the assessment of the dynamic elastomer fluid interaction is possible under compressive loads, simulating the mechanical and thermal loading of a seal in service.
This unit is able to simulate fuel system conditions and the test is a dynamic process which continuously monitors the stress relaxation behaviour of the material under test at controlled temperatures between -40 and 300°C and with fuel switch loading.
This test facility is being used for studying the effect of different fuel compositions, aromatic species and other hydrocarbons on seal performance.
- 20kW/50kW Pulverised Fuel Rig
The 20/50 KW combustion test rig is designed to evaluate coal combustion under oxygen-enriched conditions. This enables experiments to be performed whereby the over-fire air and secondary air streams may be enriched individually or in combination.
The degree of air-staging and therefore the split of the combustion air streams between secondary and over-fire air will determine the individual contributions of the two streams to the overall enrichment level of the combustion air.
The aim of this research is to generate data in order to better understand the effect of oxygen enrichment towards combustion behaviour and NOx emissions for both coal and biomass coal co-fired combustion configurations.
- Mobile Emissions Laboratory
A mobile emissions laboratory has been set up to carry out analysis of exhaust gases for a wide variety of applications.
The MEL can carry out on-site analysis of emissions on airfields, airports, and other utilities. This unit is equipped to monitor smoke, carbon dioxide, carbon monoxide, oxygen, nitrogen oxides (NOx), particulates, vibrations and unburned hydrocarbons (UHCs). UHC breakup and various other gases are also measured through Fourier Transform Infrared Spectroscopy (FTIR).
It has heated line controls to enable accurate control of sample line temperatures. Coupled with the traversable gas rake, this is able to sample and analyse the exhaust from aircraft engines whilst on the ground and can produce maps of temperature and emissions across the engine exhaust.
The experimental facility has been upgraded to do a large range of particulate matter (PM) measurements including size, number and density. Range of instruments for PM measurement include Optical Particle Counter, US EPA Method 202, US EPA Method 5i, NIOSH 5040, Centrifugal Particle Mass Analyser, Fast Aerosol Size Spectrometer (5 nano m -35 micro m) and Laser-Induced Incandescence (externally sourced).
- 250kW Furnace
Our 250kW furnace measures 3.0 m in length, 0.6 m in width and 0.9 m in height internally, is lined with a ceramic fibre and is also fitted with water-cooled steel panels.
The furnace has gas sampling measurement points located at several positions downstream of the burner wall, on one furnace side-wall.
On the opposite side-wall, a port is positioned in the near burner zone for flame visualisation. The furnace has been adapted to run on a wide range of gaseous and liquid fuels with and without oxygen enrichment and will undertake research aimed at CO2 capture and zero emission power generation.
The rig is also suited to Ultra low NOx burner development. The site has the capacity to handle up to 3MW of heat.
- 350kW Fluidised Bed Combustor
Fluidised Beds are one of the key combustion technologies available for the co-firing of a wide range of solid conventional and bio-derived fuels.
This 350kW pilot scale Fluidised Bed combustor has available a number of hoppers and feed screws to accommodate differing sources of combustible material and is equipped with a heat exchanger, particulate cyclones, and ceramic bag filter.
It is self-contained with its own combustion air supply and independent heat exchange and exhaust fans. The rig has been run on a range of materials, including bituminous coal, meat and bone meal, sewage sludge, chicken litter, bark and paper.
The combination of screw feeds allows the mixing of at least three feedstocks at any given time to produce mixtures through the main 5” screw line.
When running with Bituminous coal, it can handle a feed rate of 20kg/hr. It is fitted with a graded sand bed it operates with a fluidised bed velocity of between 0.5.-3.5 m/s and at temperatures of between 750 – 1000°C.
- 250kW Rotary Kiln Furnace
Rotary kiln furnaces can be used for a variety of different processes. The principle fields of application of indirectly heated rotary tube furnaces are the heat treatment of powdered, granular or crushed bulk materials.
The rotary kiln used has a power rating of 250kW and has been used for the gasification and pyrolysis of sewerage sludge.
This along with various metal heat treatments can be investigated with this rig. The kiln itself consists of a rotating metal tube, located within a refractory lined combustion chamber. The heated length of the furnace is 1.8m long and 0.6m diameter.
The kiln is provided with three gas burners along the tube length, temperature controllers regulate the gas flow to these burners, thus controlling the burner operation. The combustion air is supplied and controlled by a centrifugal air fan.
The flue gases pass around the rotary shell and out of the combustion chamber through a chimney stack mounted on the top of the combustion chamber of the kiln.
The pyrolysis chamber within the rotating tube heats the feedstock intensely, thereby releasing the complex hydrocarbons. The complex hydrocarbons are then broken down into smaller chained hydrocarbons. The pyrolysis process produces a hydrocarbon gas (syngas gas), condensable hydrocarbons and a solid char.
The rotary kiln facilitates a natural rotation providing agitation of the feedstock at high temperatures and allowing for a more complete conversion of all the feedstock to syngas. Product temperatures up to 1000°C are possible.
Contrary to traditional gasifiers, it sits horizontally and at a slight slope, allowing for a gravitational flow that moves the feedstock through the system. The kiln can be inclined over the range of 0-2.5degrees and at rotational speeds up to n rpm and therefore control the residence time from entry to exit.
The bed material within the rotating reactor tube is gently churned and processed towards the discharge end by vanes within the reactor’s wall. The char is discharged from the outlet of the kiln into the char/gas separator. The char settles to the bottom of the solid separator and is collected and removed via an ash bin.
The produced syngas is drawn into a condenser at approximately 800°C where the condensable gases and any tar can be collected. The remaining non-condensable gases are then drawn out through the condenser at approximately 80°C into a thermal oxidiser.
- Regenerator Test Bed
The rig is a pilot scale, 3m high, regenerator test bed. The object of the rig is to heat up a ceramic bed using a gas burner and measure how effectively heat can be transferred to a reversed air flow. The rig is to be used to (1) test commercially available regenerator bed materials, (2) develop more efficient control strategies for this type of application, (3) obtain a better understanding of the underlying heat transfer processes and how they interconnect. The rig has been designed such that the bed material can be replaced easily.
- Solid Oxide Fuel Cell Test Rig
The Solid Oxide Fuel Cell Test Rig has a 2.5kW capability, operating at 900K to 1200K with reactant humidification control, fuelled with hydrogen or simulated reformate mixtures.
It can be used for testing of single cells or stacks covering the investigation of internal reforming directly on the anode, the measurement of cell electrical performance, and materials post-analysis to investigate the effects of cell usage on their microstructure.
The exhaust gases from the fuel cell will be analysed using existing gas chromatography or mass spectrometry techniques in order to investigate the gas chemistry of the processes.
- Wind Tunnel
A wind tunnel is available with a working section of approximately 600mm sq and 1m length. The wind tunnel is capable of air flow velocities approaching 17m/s. Initially, the wind tunnel was designed to evaluate particulate measuring devices but is now available for aerodynamic assessments.
- Fuel Atomisation Test Chamber
The fuel spray rig allows the assessment of the atomisation performance from different designs of gas turbine fuel injectors and from different liquid fuels, including bio-fuels.
The rig enables the measurement of the fuel cone angle, fuel patternation quality and fuel droplet diameter distribution using laser-based techniques. This is a sealed unit capable of operating with a nitrogen atmosphere. An exhaust filter trap is fitted to ensure minimal atmospheric release of fuels.
- Numerical Capabilities
We have capabilities to generate detailed and tailored reduced chemical kinetic mechanisms for thermal-oxidative degradation for a broad range of liquid hydrocarbons including conventional aviation fuel, alternative aviation fuel, blend of alternative and conventional as well as diesel and lubricants.
The resultant mechanisms are validated against the fundamental/small scale test rigs where the impact of complex fluid flow and heat transfer characteristics are minimised. Subsequently, these mechanisms are used with CFD codes in order to simulate real time formation of surface carbonaceous deposits in engine representative conditions.
We are also developing models for predicting seal swell under different test conditions and fuel compositions.
Research group members have also been working on hydrogen / hybrid combustion, with an aim to reduce NOx emissions and increase flame stability limits. Work is also being done to reform hydrocarbon fuel, subsequently, capture the carbon and then combustion of hydrogen rich mixture, with an aim to capture carbon before combustion and reduce NOx emissions as well.
- Spey Combustor Test Rig
The Spey can combustor rig was provided by Rolls-Royce and has two versions, one houses a single can combustor and other houses a three can combustor, with a fuel spray nozzle and igniters. This rig was recomissioned by the LCCC team.
The can combustors are placed in the housing which tightly fits the combustor. A large range of instrumentation has been included in both combustor set-up’s to give detailed insight of the combustor performance including temperature profiles, pressure variations, visual inspections, vibrations and acoustics. There are two versions of this combustor rig, single can rig and triple can rig.
This rig is available for fuels testing, flame stability limits testing, injector testing, additives in fuel and air, dual-fuel injector testing, hybrid combustion testing and analyzing effect on emissions, vibrations and acoustics.
- Hot End Materail Test Rig
The effect of any post-combustion products on high-performance hot end materials and coatings of a gas turbine is essential to evaluate durability and, hence, the safety of these engine critical components.
The Hot End Materials rig is a state of the art rig previously used for similar testing by Rolls-Royce. This rig has been used for various test programs for studies on novel fuels, additives, alloys, saltwater injection and thermal barrier coatings.
The rig is currently being upgraded to inject ash/sand through the combustor and turbine blades for studying the effect of ash/sand on combustor, injector and blades.
The rig primarily consists of large duct systems which creates a combustion air supply of up to 0.6 kg/s and 300ºC. The specimens are rotated in the hot exhaust gases/flame in a spinning carousel.
The assessment is done by measuring the surface roughness, weight, carbonisation, erosion a photographic inspection. Further studies have been completed modelling the composition of volcanic ash and the solid phases
This is is being updated to inject Ash and sand through the combustor and then turbine blades for systematic evaluation of ash injection in a combustor and turbine blade.
- Pulse Detonation Engine (PDE) Test Rig
The LCCC experimental pulse detonation engine (PDE) test bed facility is the first of its type in a UK university allowing researchers to investigate the PDE cycle in a ground-based test PDE demonstrator.
The PDE’s detonation chamber is regularly instrumented to accept a suite of high-frequency measurement equipment consisting of piezoelectric pressure transducers and flame time of arrival sensors, which can measure at maximum frequencies of between 90 kHz and in excess of 1 MS/s.
This allows the research at the LCCC to investigate dynamic explosion pressures, flame speed and shock time of arrival for a range of operating conditions, and internal tube geometry configurations. The rigs flame accelerating obstacle array can be arranged flexibly according to the location of the tube flanges and can fill the entire tube or just a small section with a range of different obstacle area blockage ratios and types.
Current research topics being investigated on this rig include a focus on flame acceleration (FA), and deflagration to detonation transition (DDT) studies in gaseous fuels such as propane. The rig is capable of accepting a range of gaseous fuels and is instrumented with thermocouples and static pressure sensors in addition to combustion measurement instrumentation.
- Isothermal Tube Reactor (ITTR)
An in-depth understanding of liquid phase oxidation of middle distillate is important in aviation, marine, and ground-based transportation. It is known that the air saturated liquid fuels when exposed to thermal load, experience a multitude of chemical reactions which are collectively grouped as autoxidation.
These reactions take place at moderate temperature generating a series of primary and secondary oxygenated products including hydroperoxides, alcohols, ketones, aldehydes and carboxylic acids.
Although the identity of these products is extensively understood, the elementary reactions controlling their formation and consumption require more fundamental research.
The understanding and prediction of these reaction mechanisms and rates is critical as the autoxidation products contribute to the formation of a series of detrimental materials
including particulates, gums and solid carbonaceous deposits in fuel systems.
This test rig provides wide capability in terms of the fundamental study of liquid phase oxidation hydrocarbons by creating a near isothermal region inside the tube. The tube is centrally located inside a tubular furnace. The desired temperature is achieved by a PID controller.
An optical oxygen sensor in the fuel line allows the inline quantification of dissolved oxygen which is used for chemical kinetic study of hydrocarbons. Thermally stressed fuel can be further assessed for oxygenated products through chromatography.
The rig is capable to create simulated environment for the investigation of thermal auto-oxidation for a range of liquid hydrocarbon fuels.
This rig could be used for Thermal stability assessment at a small scale.
Low Carbon Combustion Center
The University of Sheffield
Unit 2, Crown Works Industrial Estate
Rotherham Road, Beighton
S20 1AH, UK
Phone: +44 114 222 3653
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