Carbon Brainprint Case Study: optimising defouling schedules for oil- refinerypreheat trains

In an oil refinery, crude oil is heated to 360-370°C before entering a distillation columnoperating at atmospheric pressure where the gas fraction and several liquid fractions withdifferent boiling points (e.g. gasoline, kerosene, diesel, gas oil, heavy gas oil) are separated off.The crude oil is heated in two stages. The preheat train - a series of heat exchangers - heats itfrom ambient temperature to about 270°C when it enters the furnace, known as the coil inlettemperature. The furnace then heats the oil to the temperature required for distillation.The purpose of the preheat train is to recover heat from the liquid products extracted in thedistillation column. Without this, 2-3% of the crude oil throughput would be used for heating thefurnace; with the preheat train up to 70% of the required heat is recovered. It also serves tocool the refined products: further cooling normally uses air or water. Over time, fouling reduces the performance of the heat exchangers, increasing the amount ofenergy that has to be supplied. It is possible to bypass units to allow them to be cleaned, withan associated cost and temporary loss of performance. The cleaning schedule thus has animpact on the overall efficiency, cost of operation and emissions. The group at the Department of Chemical Engineering and Biotechnology at Cambridgedeveloped a scheduling algorithm for this non-linear optimisation problem. It yields a good,though not-necessarily optimal, schedule and can handle additional constraints, such as thepresence of desalters with specific temperature requirements within the preheat train. This isnow being developed into a commercial software product. Data from two refineries - one operated by Repsol YPF in Argentina and the Esso FawleyRefinery in the UK - were used to model the systems and test the algorithm. For the Repsol YPF refinery, when compared with current practice and including a constrainton the desalter inlet temperature, the most conservative estimate of the emissions reductionwas 773 t CO2/year. This assumed a furnace efficiency of 90%. The emissions reductionincreased to 927 t CO2/year at 75% efficiency and 1730 t CO2/year at 40%. These were basedon a stoichiometric estimate of the emissions from the furnace. Using a standard emissionfactor increased them by 7.4%. For Esso Fawley, the estimated emission reduction compared to no maintenance was1435 t CO2/year at 90% furnace efficiency. This increased to 1725 t CO2/year at 75% and3225 t CO2/year at 40% efficien

Analysis of the 2007/8 Defra Farm Business Survey Energy Module

Key points This study has delivered an invaluable baseline estimate of energy use and greenhouse gas (GHG) emissions on commercial farms in England. Energy use and GHG emissions associated with particular commodities were quantified and results broadly agreed with those derived by Life Cycle Assessment, but with much scatter in the environmental performance of farms.Direct energy use on farms was generally less that indirect (embedded) energy use, except for horticulture, which is dominated by heating fuel use. In contrast, most GHG emissions are incurred on farms, rather than as embedded emissions.Scatter in both environmental and economic performance underlies the somewhat disappointing finding of no clear positive link between farm financial performance and energy use or GHG emissions. However, the mere existence of these ranges shows that there is scope for improvement in both financial and environmental performance and that there is no apparent barrier for both to be achievable in harmony. The recording of such farm-level energy data is essential for the future, as it should enable improvements to be made in efficiency of energy use. The improved UK agricultural GHG inventory will depend on high quality energy data on agricultural activities. This study will be invaluable in identifying the level of detail needed. Future data requirements include: contractor work rates and fuel use per unit area and per unit time, fertiliser and pesticide use by brand name, enhanced output data, especially animal live weights, and horticultural produce recorded by weight rather than by value

SARS-CoV-2 Omicron is an immune escape variant with an altered cell entry pathway

Vaccines based on the spike protein of SARS-CoV-2 are a cornerstone of the public health response to COVID-19. The emergence of hypermutated, increasingly transmissible variants of concern (VOCs) threaten this strategy. Omicron (B.1.1.529), the fifth VOC to be described, harbours multiple amino acid mutations in spike, half of which lie within the receptor-binding domain. Here we demonstrate substantial evasion of neutralization by Omicron BA.1 and BA.2 variants in vitro using sera from individuals vaccinated with ChAdOx1, BNT162b2 and mRNA-1273. These data were mirrored by a substantial reduction in real-world vaccine effectiveness that was partially restored by booster vaccination. The Omicron variants BA.1 and BA.2 did not induce cell syncytia in vitro and favoured a TMPRSS2-independent endosomal entry pathway, these phenotypes mapping to distinct regions of the spike protein. Impaired cell fusion was determined by the receptor-binding domain, while endosomal entry mapped to the S2 domain. Such marked changes in antigenicity and replicative biology may underlie the rapid global spread and altered pathogenicity of the Omicron variant

Investigation of hospital discharge cases and SARS-CoV-2 introduction into Lothian care homes

Background The first epidemic wave of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in Scotland resulted in high case numbers and mortality in care homes. In Lothian, over one-third of care homes reported an outbreak, while there was limited testing of hospital patients discharged to care homes. Aim To investigate patients discharged from hospitals as a source of SARS-CoV-2 introduction into care homes during the first epidemic wave. Methods A clinical review was performed for all patients discharges from hospitals to care homes from 1st March 2020 to 31st May 2020. Episodes were ruled out based on coronavirus disease 2019 (COVID-19) test history, clinical assessment at discharge, whole-genome sequencing (WGS) data and an infectious period of 14 days. Clinical samples were processed for WGS, and consensus genomes generated were used for analysis using Cluster Investigation and Virus Epidemiological Tool software. Patient timelines were obtained using electronic hospital records. Findings In total, 787 patients discharged from hospitals to care homes were identified. Of these, 776 (99%) were ruled out for subsequent introduction of SARS-CoV-2 into care homes. However, for 10 episodes, the results were inconclusive as there was low genomic diversity in consensus genomes or no sequencing data were available. Only one discharge episode had a genomic, time and location link to positive cases during hospital admission, leading to 10 positive cases in their care home. Conclusion The majority of patients discharged from hospitals were ruled out for introduction of SARS-CoV-2 into care homes, highlighting the importance of screening all new admissions when faced with a novel emerging virus and no available vaccine

Guidance for the calculation of carbon brainprints of higher education institution activities

This document is intended to provide a guide to assessing a carbon brainprint. It was developed as the project case studies were conducted, starting from a set of general principles and becoming more specific. It is guided by the principles used by the IPCC, PAS 2050:2008 and Carbon Trust good practice. However, a carbon brainprint is not an assessment of the life cycle greenhouse gas emission of a specific good or service. In particular, the emphasis is mainly on total changes in emissions, not the functional unit, and general estimates rather than product-specific ones may be required. The guidance covers definitions, basic principles, system boundaries, attribution, uncertainty analysis and the scope and limits of application of the method

Carbon Brainprint Case Study: training for landfill gas inspectors

Anaerobic deterioration of biodegradable wastes in landfill sites is an important source ofgreenhouse gases. Of the estimated UK total of 2330 kt methane emitted in 2008, 966 kt(equivalent to 24 Mt of carbon dioxide) came from landfill, compared with 876 kt from livestockagriculture, the next largest source. Increasing the amount of methane that is recovered andused as fuel is an important method of reducing emissions. In 2008 Cranfield University was asked by the Environment Agency (EA) to run a 12 day course to train 12 EA officers, based on the knowledge of a retired EA industry expert. At the end of thecourse, the students split into two groups, each of which undertook 12 site visits. These 24sites were subsequently assessed by the EA, who estimated that the additional measuresrecommended had collected an additional 7,600 m3/hr of landfill gas. A further 12 officers havenow received the advanced training, and another 70 have attended a foundation course inwhich they learn how to audit and assess landfill gas controls on sites. The additional collection of methane resulting from the first set of visits is equivalent to453 kt CO2e/year. Extrapolating from this by making conservative assumptions about possiblediminishing returns, the savings to the end of 2010 from the two groups (the retrospectivebrainprint) are about 1,330 kt CO2e with a 95% confidence range of 1,091-1,570 kt CO2e. Usingthe same assumptions, if both groups continue working for a further three years, the savingsover the five year period (the prospective brainprint) will be 5,380 kt CO2e with a 95%confidence range of 3,695-7,309 kt CO2e

Carbon Brainprint Case Study: ceramic coatings for jet engine turbine blades

Ceramic thermal barrier coatings (TBCs) are applied to jet turbine blades to protect them from the high temperature gases leaving the combustion chamber and to increase the efficiency of the engine. Professor John Nicholls of the Surface Science and Engineering Group, Cranfield University has been working with Rolls- Royce plc for about 17 years to improve the insulating performance of TBCs. As a result, the TBCs used in the current generation of aircraft turbofan jet engines achieve a temperature drop about 80ºC greater than at the start of the work, with an estimated fuel saving of about 1%. This case study considered two engine types: Trent 700, used on about half the Airbus A330 aircraft currently in service, and Trent 500, used on all Airbus A340-500 and A360-600 aircraft. The greenhouse gas emissions considered were, in order of magnitude, carbon dioxide from combustion of the fuel, emissions during extraction and refining of the fuel, and emissions of other greenhouse gases during combustion. Emissions associated with transport of the fuel were found to be negligible compared with these, and all emissions not related to fuel consumption, for example manufacture of the coating, were also assumed to be insignificant or excluded from the assessment because they were unaffected by the change in the TBC. The baseline fuel consumption during each flight phase (landing and take-off cycle and cruise) was estimated from publicly available data. Airline activity data for A330 and A340 models from European operators was taken to represent typical patterns of use, enabling annual emissions per aircraft to be calculated. Data on current operating aircraft and orders were then used to estimate the total current and projected future emissions. From these, the higher emissions that would have occurred in the past if the improved TBCs had not been used, and the corresponding future emissions, were estimated. The best estimates of the current emissions (the retrospective brainprint) for individual aircraft were 1016, 1574 and 1646t CO2e/year for A330, A340-500 and A340-600 respectively, giving 568 kt CO2e/year for the total fleet. Including all the aircraft on order, the prospective emissions reduction was 833kt CO2e/ year. Assuming a service life of 20 years, the total brainprint was approximately 17MtCO2e. An uncertainty analysis was performed with assumed uncertainties for aircraft activity, fuel consumption and the efficiency change. The 95% confidence interval for the current annual emissions reduction was 429-721kt CO2e/year excluding the efficiency change uncertainty, and 258-1105 if it was included. The relative changes in the other output measures were similar. Assuming that older engines do not and will not benefit from the improvement, reduced the total brainprint to 14MtCO2e. The assessment did not include an adjustment for the effect of emissions at high altitude, which would increase all the outputs by a factor of 1.9

The water footprint of English beef and lamb production

Recent reports highlighting large quantities of water required to produce a kilo of meat have attracted media attention, leading to debates over the role of meat in a sustainable diet. Such reports frequently quote figures based on global averages and therefore conceal significant regional variation, ignoring the source of the water required and local climatic conditions. This report attempts to quantify the water footprint of English beef and lamb production, combining the water simulation model Wasim and the Cranfield Life Cycle Assessment model to calculate the water required to produce a tonne of beef and lamb meat. This method accounts for all water required by grass and crops in addition to drinking water and other requirements. Water use is considered in three categories; green, blue and grey water. Results show that beef has a water footprint of 17,700 m3/t carcase weight and lamb 57,800 m3/t. Of these, 84% and 97% respectively is green water use, i.e. evapotranspiration of rainfall on crop and grassland. Without this breakdown there is no distinction between rainfall and irrigation supply (blue water), which means that UK beef production may appear similar in impact to countries where irrigation of feed crops is dominant. This report highlights the importance of considering water use in context; in this case, for a temperate, wet climate such as England where crop and grassland water requirements are adequately met by green water from rainfall. Upland and hill production systems have higher water footprints, mostly because grass yield is lower. However, it is shown that rainfall surplus per tonne grass production is still highest in these regions, so that export of water for other human purposes is possible from these regions.EBLE

Carbon Brainprint Case Study: improved delivery vehicle logistics

Road transport accounts for about 20% of the total GHG emissions of the UK, and HGVs andLGVs are responsible for about one-third of these. The total direct GHG emissions from HGVsand LGVs in 2008 were about 40 Mt CO2e. Dr Andrew Palmer, a Cranfield University visiting fellow and former PhD student contributed tothe transport recommendations for the food distribution industry following publication of TheFood Industry Sustainability Strategy. These recommendations were taken up by IGD as part ofthe Efficient Consumer Response (ECR - UK) initiative and implemented with 40 leading UKbrands. They reported that this initiative had taken off 124 million road miles (equivalent to 60million litres of diesel fuel) from UK roads over three years (2007-2009) and 163 million roadmiles up to 2010, with a target of 200 million road miles by the end of 2011. The quoted reduction in vehicle use up to 2010 is equivalent to 250 kt CO2e, but this cannot allbe attributed to Cranfield University's carbon brainprint, because Dr Palmer was only one of theauthors of the report and he was not an employee of the university at the time. We estimate theattributable brainprint to be 56 kt CO2e with a 95% confidence range of 32-87. Assuming that this is maintained until 2020, and assuming a 1%/year increase in efficiency independent of thiswork, which will reduce the future brainprint, gives an estimate of 187 kt CO2e (102-295) for theperiod 2007-2020

Carbon Brainprint Case Study: novel offshore vertical axis wind turbines

As part of the transition to a ‘low carbon economy', renewable technologies are expected toplay an increasing role in reducing dependence on fossil fuels for energy and electricity. Windpower in particular is likely to become a much larger contributor to the UK's energy mix. Thecurrent dominant design for large, grid-connected wind turbines is a three blade rotor with ahorizontal rotating axis. The concept of a vertical axis wind turbine (VAWT) is relatively new, buthas several advantages over horizontal axis alternatives. It is able to capture the wind from anydirection, and the vertical axis is such that the rotor equipment is located at base level, makingit is simpler and less costly to install and maintain. The Energy Technologies Institute (ETI) is a UK-based company formed from global industriesand the UK government. One of three projects looking at new turbine design and concepts foroffshore wind is the Novel Offshore Vertical Axis (NOVA) project, a UK-based consortiumlaunched in January 2009 to look at the feasibility of a NOVA turbine. achieved through the installation of NOVA wind turbines, in comparison to conventionalhorizontal axis wind turbines (HAWTs) for offshore power generation. The increased powerrating of the NOVA turbines compared to current HAWTs is expected to provide considerablereductions in lifetime greenhouse gas emissions. It compared the emissions from 1 GWinstallations over 20 years, based on a life cycle analysis of construction, operation anddisposal. The comparison used the popular Vestas V90 3 MW model and the proposed NOVA10 MW units. The estimated lifetime emissions were 521 kt CO2e for the conventional design and419 kt CO2e for NOVA. Using budget share to attribute the reductions to the project partners,Cranfield's brainprint was 34 kt CO2e. As there are no current NOVA units in operation, there were high uncertainties associated withthe estimates. A Monte-Carlo simulation resulted in a mean difference in emissions betweenthe two installations of 102 kt CO2e, with a standard deviation of 108