Alexander Collard's Webpage

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Postgraduate Researcher

Phone: +44 (0)20 7679 3801

Email: alexander.collard.09@ucl.ac.uk

Department of Chemical Engineering
University College London
Torrington Place
London WC1E 7JE
United Kingdom

Studied Chemistry at Nottingham University and graduated in 2006.

Worked for Procter and Gamble up to December 2008 in products research of health care products.

Attended the 2009 MSc Chemical Engineering course at UCL, from there began a PhD at UCL in December 2010.

Research project

Title: Blowdown Simulation of CO2 Pipelines

Supervisors: Prof Haroun Mahgerefteh

As part of the challenge to reduce the impact of global warming, pressurised pipelines are considered to be the most practical option for transporting captured CO2 from fossil fuel power plants for subsequent sequestration. This has significant implications for Europe given its heavy reliance on coal fired power plants for its electricity generation and the inevitable routing of CO2 pipelines near populated areas.

My project is part of a major study sponsored by the UK National Grid (COOLTRANS Project) based on the development and validation of mathematical and computational tools for the safety assessment of pressurised CO2 pipelines. My work primarily focuses on blowdown simulation of CO2 pipelines. The rapid decompression or blowdown of pipelines is contemplated when emergencies arise. However such operations present pipeline design and safety engineers with a dilemma.

The primary purpose for blowdown is to reduce pressure and remove inventory in the least amount of time. However, the rapid depressurisation results in a dramatic drop in the fluid and hence the pipe wall temperature in contact with it. In the case of dense phase CO2 such temperatures may reach as low as –60°C during blowdown. If the wall temperature falls below its Ductile-Brittle Transition Temperature (DBTT), brittle fracture is likely to occur. Low fluid temperatures can also lead to the formation of solid CO2 hydrates in cases where free water is present resulting in pipeline blockage.

In this research project a validated discharge model previously developed will be employed to predict the minimum fluid and pipewall temperature during emergency blowdown.

Taking account of backfill heat transfer characteristics, a number of blowdown diameters for the range of pipeline conditions of interest in the COOLTRANS project will be considered. Based on the results obtained, the optimum blowdown diameters will be recommended. These recommendations will take into account the number, the positioning and closure dynamics of Emergency Shut Down Valves (ESDV) and the minimum pipewall temperature relative to its DBTT.

Page last modified on 18 jun 12 16:34