Environmental Solutions
temperatures. Because they don’t contain aromatics or sulphur-
containing contaminants the liquid fuels produced are typically of higher quality and burn cleaner than petroleum- based diesel and jet fuels, resulting in lower emissions of NOx and harmful particulates. BTL fuels also offer substantial reductions in greenhouse gas emissions. They are compatible with the current fuelling infrastructure and offer several engine performance benefits over today’s diesel and jet fuels. These benefits have been demonstrated and recognised by a number of prospective biofuel users, including the US Air Force. The distributed production of biofuels involves the
production of biofuels in small scale plants located near the source of the waste and the markets for the fuel. Microchannel reactors are designed for economical
production on a small scale. FT microchannel reactors are compact and have channels with diameters in the millimetre range. Conventional reactors are many times larger and have channel diameters in the centimetre range. Because the smaller diameter channels in microchannel
reactors dissipate heat more quickly than those in conventional reactors, more active catalysts are used to boost the conversion rates to an economic level (Fig. 2). When used with a new FT catalyst developed by Oxford
Catalysts, the Velocys microchannel FT reactor exhibits conversion efficiencies in the range of 70 per cent per pass. A single microchannel reactor block, measuring 60 x 60 x 60 cm, might produce over 30 barrels (bbls) of liquid fuel/day. In contrast, conventional FT plants typically exhibit
conversion efficiencies in the range of 50 per cent or less per pass. They are designed to work at minimum capacities of 5000 bbls/day, and function well and economically only at capacities of 30 000 bbls/day or higher. The significant performance indicators achieved in
the demonstration unit include: near isothermal reactor temperature profile; pressure drop as expected; high quality synthetic fuel being produced (alpha value >0.9); and robust responsiveness to shutdowns and start-ups. An isothermal temperature profile indicates that the
catalyst bed of a reactor is operating at an even temperature throughout, and that the temperature control system (in this case the microchannels) is working efficiently. Pressure drop describes the difference between pressure upsteam and downstream of the catalyst bed. Minimisation of the pressure drop over a catalyst bed is important to minimise process costs for a given throughput. Productivity is a measure of the amount of product that can
be produced from a given unit of catalyst per hour. Volumetric productivity is the amount of product that can be produced per litre of catalyst per hour. The alpha value measures the probability of a hydrocarbon chain propagating rather than terminating (producing a shorter hydrocarbon); optimised FT catalysts should achieve an alpha value of 0.90 or above. Robust responsiveness to planned and unplanned shutdowns
and start-ups is required to ensure that activity and productivity can be recovered quickly and completely after an outage. Meanwhile in the UK, INEOS Bio today announced
that it has received an offer of a £7.3m grant towards £52m construction costs for the first commercial plant in Europe using its advanced BioEnergy Process Technology.
Fig. 2. Microchannel reactors dissipate heat more quickly than those in conventional reactors. Picture courtesy of Oxford Catalyst Group
The plant, to be located at the INEOS Seal Sands site in the Tees Valley, is designed to produce 24 000 tonnes per year (30 million litres) of carbon-neutral road transport fuel and generate more than 3MW of clean electricity for export from over 100 000 tonnes per year of biodegradable household and commercial waste. This would provide the biofuel requirement of around 250,000 vehicles per year running on E10 (a blend of 10 per cent by volume bioethanol and 90 per cent by volume petrol) and the electricity needs of 6000 households.
Speaking about the announcement, Peter Williams, ceo
of INEOS Bio, said: “Using our technology, the waste that is collected from homes and offices and otherwise thrown away, can be re-cycled into clean biofuel for cars and renewable electricity for homes and industry.” Subject to final agreements, this advanced bioethanol
plant is due to be completed by 2012, creating around 40 new jobs at the plant and 350 jobs in the construction phase. Following the completion of a feasibility study by INEOS
Bio, DECC has approved funding of £4.5m for this next phase of the project. The Regional Development Agency One North East is also investing £2.8m, of which £1.8m has been secured through the Tees Valley Industrial Programme. The INEOS BioEnergy process technology combines
thermochemical and biochemical technologies to achieve energy-efficient and low-cost biofuel production from a wide range of biomass materials, including household and industrial waste. At the heart of the INEOS Bio technology is an anaerobic fermentation step, through which naturally occurring bacteria convert gases derived directly from biomass into bioethanol. This bioethanol production is integrated with combined heat and power generation. The process supports high recycling and high landfill diversion rates and an independent life cycle assessment indicates that the bioethanol produced would deliver 100 per cent green house gas savings compared to using petrol in today’s cars. n
www.engineerlive.com 43
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60