Request for Proposals - Assessment of High Hydrogen Fuels
30 June 2010
30th June 2010
Assessment of Control and Safe Operation of Gas Engine and Gas Turbine Operations for High Hydrogen Content Gases in Combined Cycle and CHP applications
The closing date for this RfP was 23 August 2010. This RfP has now closed.
Hydrogen can be derived as a fuel source from a number of processes, either directly or as a by-product. Within the UK context to 2050, there are a number of potential sources of high hydrogen content gases that could be exploited within this timeframe:
IGCC with CCS (coal, biomass, gas)
H2 gas CHP opportunities (coke oven gas, refinery/chemical streams, syn-gas production from coal, town gas)
Hydrogen fuel derived from excess generation from wind/nuclear
Biomass gasification projects
Safe Operating Limits and Safety Mechanisms for High Hydrogen Content Power Systems
The aim of this project is to develop a deeper knowledge and understanding on the safe operating limits and safety mechanisms required to manage combined cycle and CHP systems that utilise high hydrogen content gases for power conversion in both gas engines and gas turbines; in order to both assess the technology development opportunity and scale-ability of systems in this area. The specific core area of concern is in assessing the risk of flame-out, leading to a deflagration to detonation transition (DDT) and subsequent explosion; whilst exploring options that could be used to mitigate this risk.
Work has been conducted by a number of institutions around defining LEL’s for high hydrogen systems; however for most systems, the data to assess whether a DDT would occur is not available. HRSGs and other heat transfer elements in gas turbine exhausts act as obstructions to the flow and may serve to accelerate any deflagration and cause a DDT.
DDT does not always occur in highly obstructed environments and whether it can occur depends on mixture composition, concentration, conditions (temperature, pressure etc.), geometry, and scale. Detailed information to assess whether DDT could occur in gas turbine exhausts including HRSGs is not available and it is not possible to accurately assess whether DDT can realistically occur in applications with high hydrogen fuels.
Thus current mitigation options that exist in industry often necessitate running systems at a significantly reduced efficiency; dealing with nuisance trips; or, given the precautionary principle, ruling out potential opportunities.
Given the overall potential opportunity space in developing high hydrogen power systems, it is clear that addressing the safety concerns in operating these systems is paramount.
The fundamental requirements of this work are to provide empirical data on the DDT potential of high hydrogen power systems; and to establish methods for monitoring changes in gas composition to enable safe and efficient control of the combustion and exhaust phases in gas engines and gas turbines. The work will need to explore geometry effects, exhaust temperature variation, turbulence levels, fuel composition, effect of duct burners, vent configurations, dead space elimination mitigation, ignition sources, and more. Full functional requirements are outlined in section 3 of this document.
The core outputs must be experimentally derived and represented in such a way that they can be used for the parameterisation of CFD models; and be used directly for empirical assessment of DDT. It is envisaged that two test rig scales will be required in order to explore the effects of geometry and scale-up requirements of larger scale systems.
The project comprises of the following three work packages:
Work Package 1: Literature Review
Work Package 2: Experimental investigation into the limits of flammability, ignition and DDT potential under a range of high hydrogen fuels for CHP and CCGT applications
Work Package 3: Investigation into Fast-Response Gas Composition Measurement for Engine Controls
Work Package 4: Evaluation and Recommendations Report
The deadline for submitting an intention to bid is 16 July 2010