Crowes APEA.qxp
7/3/07
7:25 am
Page 32
Articles
Experience of Stage 2 Vapour Recovery in the UK By Phil Lambeth, BP Global Fuels Technology / Global Alliance Stage 2 Vapour recovery has been with us in most countries in Europe and the US since the late 1980’s. The European directive setting a cap on total Volatile Organic Compound (VOC) releases was published in 1992 aiming at total VOC reductions by 2010. As the deadline approaches those countries which have not yet done so are looking to Stage 2 vapour recovery to help meet their declared targets. Most of the early adopting countries created their own regulations around approvals and performance but essentially we have the same systems doing the same job in all existing countries. The good news for the UK is that the regulations published recently by DEFRA here will allow equipment approved to any of the existing European standards to be accepted. There will not be a whole new set of equipment type approvals for manufacturers, users and regulators to work through. So having been done everywhere else, several times, what more is there to learn for the project in the UK? While the basic principle we all follow is the same there are historic differences in details of how we build, use and regulate our petrol filling stations which affects the end result. This paper shares some of the things BP has found in 6 years of fitting Stage 2 systems in the UK. It covers the operational reliability of components and looks at some of the technical issues we have faced when we started pumping petrol vapour back to the tanks. The System Stage 2 vapour recovery is all about collecting the vapour displaced while cars are being filled on the forecourt. In the UK we currently release about 30,000 tonnes of petrol vapour into the atmosphere each year from this source. Petrol vapour contributes to the formation of ground level ozone, a green house gas which can result in health problems for humans and is hazardous to plant life. While vapour lost like this is only about 2% of the total volatile organic releases it is growing in proportion as other areas are controlled and importantly is one we can do something about. History BP’s implementation in the UK started when the original European VOC Directive was published back in 1992. Like many others we started at that time to fit the underground 32
Pumps need to be fitted with
PVR II will collect the vapour displaced from car fuel tanks as they are filled on the forecourt
• a new nozzle, coaxial hose and splitter adaptor • a vapour pump • a way to match the vapour recovery flow rate to the delivery flow rate which can be:
1. a mechanical proportional valve in a special nozzle 2. an electronically controlled proportional valve in the pump 3. an electronic speed control for the vacuum pump motor
pipework required to transfer the vapour from the pump back to the tank. A number of options for this have been considered and tried. The vapour flow rates and output pressure of the pumps mean that you don’t actually need a big pipe to get the vapour back to the tank. Having looked at smaller bore pipe systems we have however come back to standard 1.5” or 2” pipes underground, connected into a single return to a tank because these are standard sizes used on the forecourt, easily handled and big enough to avoid being damaged. We have tried pipe in pipe systems – pulling a 15mm flex pipe back down an existing suction line to avoid any need for digging up forecourts when retrofitting. These have had some success in Germany but the key difference is that the German experience was based on welded pipe systems. In the UK we have screwed joints. At every connection and bend where the pipe is screwed into the fitting there are internal sharp edges. In our tests we could not get the draw wire past these edges let alone get a pipe through. So that was abandoned. In late 1999 after publication of proposals for Stage 2 in the UK by the Dept of the Environment we looked at the numbers and given that fitting as new was less than a quarter of the cost of retrofitting decided there was a clear business case to implement stage 2 on all new sites in the UK from them on.
New APEA tel/fax 0845 603 5507
To date we have 163 sites in the company network operating with Stage 2 vapour recovery. Reliability Maintenance for Stage 2 has not been a priority. If a problem was found during other works to the dispensers then it would be fixed but we have had no specific regime of call outs or checks to make sure they are working. That noted BP’s maintenance providers advise that the vast majority are all working and when we have had occasion to check we have found that they are operating more or less as originally set up. We are comfortable that the stage 2 systems we have installed are operating reliably. The selected systems were chosen for reliability based on our operating experience elsewhere in Europe. Dispensers were supplied by Tokheim and in the last 4 years principally by Wayne.
All use the Elaflex vapour recovery nozzle, Stage 2 hoses with integral swivels and break couplings and these have all proved reliable in operation. Nozzle issues – spout damage or wear at the venturri tube - are the same as for standard nozzles. There are no additional issues affecting these Stage 2 components in the equipment.
