8th HEXAG Meeting at Brunel University

9th December 1997

The 8th HEXAG meeting was held at Brunel University, Uxbridge, on 9th December 1997, and 55 members attended. After a welcome by Professor Nicos Ladommatos, Head of the Department of Mechanical Engineering, those present heard a wide range of technical presentations, with the subject of heat exchanger fouling being one of the principal themes of the day. First, however, David Reay introduced the new activities of HEXAG, (as described in the Editorial in this issue of HEXAG News).

The technical presentations were 'kicked off' by Ian Wilson of Cambridge University, who gave a version of his presentation first heard at the 'Focus on Fouling' meeting held earlier in the year at the Institute of Petroleum. This was concerned with the scheduling of cleaning in heat exchanger networks, and he is receiving support for this work from the EPSRC and the petrochemicals industry. Ian stated that scheduling was important in this context because of the high cost of cleaning, and the cost of the energy use caused by fouling. Ian then defined the scheduling problem, data reconciliation, the methods used and his plans for future work.. The main problem area was the crude distillation unit, where the fouling cost penalty was $100,000 per annum for a 1 K drop in the coil inlet temperature.

The project was principally about the monitoring of plant performance - one needs to know the fouling resistance to see if the mitigation methods are working. Then one can take appropriate control by scheduling of the cleaning actions.

A case study from the Esso Fawley refinery was presented. This is a 330 kbbl/day plant, and unit PS3 was examined, this processing 1250 m3/h of crudes. A heat exchanger network of 67 units with a total duty of 210 MW is involved, and the typical period between shut downs was 3-7 years. Data collection commenced in 1995. Indications to date are that the fouling resistances are greater than the TEMA values.

Marcus Lentz of GEA Canzler and Andy Pitt of ENTEC then told us about spiral heat exchangers (SHE) and the major installation planned for an effluent treatment plant at the Wilton, Teeside petrochemical complex. Marcus gave us an interesting perspective on the historical development of the SHE and described the operating condition ranges, which the GEA Canzler product can accommodate. A typical application in a fouling environment involved three series units for sludge treatment. The SHEs were used to heat, disinfect and cool the sludge, and the units also functioned as heat recovery units. There are three main variants of the SHE: Countercurrent, crossflow and a hybrid unit where the inner section operates in crossflow and the outer section is countercurrent. This type of combination is used mainly for condensation of vapours in the presence of noncondensible or inert gases.

Andy Pitt then described the role of the SHEs, which his company is installing, on a PTA effluent treatment plant at ICI Wilton. ENTEC specialises in biological waste water treatment plant and in treating waste water from petrochemical installations. In this case the PTA effluent needs to be cooled from 65oC to 35oC in order to be successfully treated. A pilot plant has been installed on site in order to study the fouling behaviour, using a grossly supersaturated effluent stream, which gives a high potential for crystallisation. The plant is being used to assess the nature, rate and degree of fouling, quantified by measuring reductions in heat transfer coefficient and increases in pressure drop. The effect of process variables and cooling water flow rate is also being examined. An optimum chemical cleaning schedule using a caustic solution will be determined, and the impact of fouling on any downstream equipment assessed. (See separate item about the availability of this pilot plant).

The process intensification work at Newcastle University continues to generate new ideas. This time Roshan Jachuck introduced us to the use of spinning disk technology for the rapid processing of foodstuffs. For pasteurisation, for example, Roshan said that one could process the fluid in one second, and by doing this at a higher temperature, without degrading the product, one could accelerate the rate of bug destruction in a much shorter residence time. The fouling in conventional milk processing plant could also be alleviated using this method.

Roshan also described the benefits of spray evaporation for cooling pre-packaged foods. This cooling process is a bottleneck in the production process and spray evaporation was a route to much faster cooling. Energy costs could be reduced by up to 50%, he also stated.

David Reay then introduced some of the new heat pipe concepts described at International Conferences in Stuttgart and Minsk, held in September 1997. Lap-top computers are one of the growth areas for heat pipes, for cooling of the central processing unit (CPU). The Pentium CPU generates 17 W, about three times the heat output of a 486DX chip. Heat pipes are now being used to take heat from these chips to the chassis of the lap-top, and often into the lid, using a flexible variant. The heat pipe has to cost $1.50, while the chip cost $150.00!

Another use David highlighted was the production of 'ice islands' in the Arctic for the Russian gas and oil exploration companies. Vertical heat pipes are being used to create artificial ice islands by using the cold ambient air to cool and freeze the water around the evaporator sections. The air temperature is of course much colder than the seawater, down to -30oC. In three days an ice cylinder of 0.5 m in diameter can be formed around a 0.04 m diameter heat pipe. Multiple tubes are used to construct the ice island. With Christmas coming soon, the heat pipe 'cooking pin' came up in discussion. These super conducting skewers for meat allow reductions in cooking time. For a 'bird' two are needed, inserted through each leg!

David Butterworth then gave information on the proposed Fouling Guide, a Best Practice Guide to Minimise Fouling. The idea for this arose out of the 'Focus on Fouling meeting mentioned above, and the discussion after the meeting in London suggested that a Guide should cover points such as fouling mechanisms, designing for low fouling, operation to avoid or minimise fouling, monitoring, revamps to overcome fouling problems, and cleaning. The Guide would be directed at the oil, petrochemical and bulk chemical sectors. David is keen to find companies who would like to participate - the support per organisation needed is minimal - £2000 - and at least one potential contributor was located at the HEXAG meeting. Contact David on tel. O1235 525 955 or fax. 01235 200 906 if you are interested.

We are familiar at HEXAG meeting with reports on support for R, D&D. For the first time we had a talk from Dan King, representing EPSRC, which funds much of the research at UK Universities. Dan gave us lists of relevant projects within his portfolio (see Meeting Minutes for details), and explained the operation of the Programme, and the ways in which industry could participate, via a University. Dan is moving into the EPSRC Combustion Programme, but for the heat and mass transfer area: Contact Lucy Miles, tel. 01793 444478, Email: Lucy.Miles@epsrc.ac.uk

Will Blyth, who has taken over responsibility from Mike Morrell as the ETSU Project Officer for R&D in the process industries and heat exchangers, said that ETSU was currently producing an R&D strategy for the process industries, and feedback from HEXAG members would be welcome. Heat exchanger R&D is still being supported, and process intensification has been identified as an important strategic area. A special HEXAG meeting will be held in or around September 1998 on heat exchanger-reactors, and will be an opportunity for members to generate and present new ideas on process intensification. Contact: Will Blyth at ETSU, tel. 01235 433012, fax. 01235 433727.

Bob Berryman updated us on the status of the ISO Standards for process heat transfer equipment, including one on plate heat exchangers. Contact Bob on: tel. & fax. 01235 767579. Steve Hamlin, a research student at Brunel sponsored by Normalair-Garrett, reported on the performance of evaporative spray cooling in air cycle technology. It was found that the cycle coefficient of performance rises significantly with spray cooling. Contact: Mike Street at NLG, fax. 01935 427600. Bill Fletcher, who recently left EA Technology to set up his own consultancy, gave us his views, based on the experience of a wide range of projects, on the importance of heat exchanger technology. Contact Bill by fax on 01978 852118.

The afternoon workshop, which was followed by a laboratory tour, was introduced by David Reay, and then expanded to include many of the educational aspects of heat exchangers and their appreciation in both academia and industry. The suggestions ranged from Universities 'borrowing' heat exchangers, including compact types, from manufacturers to determine by measurement the 'f' and 'j' factors, to putting lectures on the Web and making more CD-ROMs available on the subject. There were also suggestions that HEXAG could, as a body, assist with marketing of products for such uses in the USA and the Far East.

This will be a subject we will return to in the future, no doubt.

Our thanks go to Brunel University for providing excellent facilities the meeting. The table of food set aside for vegetarians at lunch proved popular even with those of us who have a need for heat pipe cooking pins, and Savvas Tassou, our host, conjured up some welcome bottles of wine!

ETSU Considering Higher Education Initiative

Following the last meeting of HEXAG, where the availability of Energy Efficiency Best Practice Programme material was discussed, ETSU is now considering how to meet the needs of Universities who wish to incorporate this information into their courses. Various publications have been produced relating to compact heat exchangers, and the aim of these has been to help spread good practice with regard to:

This information has been primarily targeted at industrial users. However, it is acknowledged that there is a requirement to assist in the training of engineers so as to raise the profile and level of understanding of compact heat exchangers. Various options are being considered, ranging from schemes to make the existing literature more widely available, to the development of specific training packages. As these ideas become more focused, the views of HEXAG members will be welcome, and updates will be given at future HEXAG meetings.

If you have enquiries or comments, contact William Blyth at ETSU, Harwell, Didcot, Oxfordshire OX11 0RA. Tel. 01235 433012, fax. 01235 433727.

Another Step Closer to FP5

The EU's Research Ministers reached their first concrete conclusions on the Commission's proposals for FP5 at a Research Council meeting in Brussels on 10 November 1997. The structure and content of the programme changed slightly from that originally proposed by the EC, most delegated favouring five thematic programmes (instead of the original three). These five programmes would address:

Substantial agreement exists for the creation of a number of additional key actions, including 'Planetary changes, climate and biodiversity', which may well be relevant to our activities. In addition to the five above topics, there are three 'horizontal' programmes, covering international co-operation, innovation and SMEs, and human potential. If these are similar to the activities in FP4, again there will be opportunities for HEXAG members to participate.

Interestingly, while the EC wants to retain full control of short-listing projects for support, the Council wanted the Programme Committees, which are committees of Member States' representatives, to have a say in this activity, in addition to their broader steering role. The ability of proposers from the UK to interact closely with the UK representatives on these committees will be welcome. The Commission is also proposing a 'one-stop shop' for SMEs to access the calls for proposals. The EC also proposes to appoint Advisory Groups of key researchers from academia and industry to guide key actions or groups of key actions.

The full text of the Commission's working document can be accessed at http://www.cordis.lu/fifth/home.html

INTAS Call for Proposals

INTAS, the International Association for the Promotion of Co-operation with Scientists from the New Independent States (NIS) of the Former Soviet Union, has recently announced its 1997 call for joint research projects and networks. The deadline for proposals is March 18, 1998. Research areas, and network opportunities, include environment, energy and engineering sciences - plenty of opportunities for HEXAG members. The UK is an INTAS member, and most of the former Soviet Union, (except the Baltic republics) are classed as NIS.

There is an open call covering any of the NIS, and also INTAS-Belarus, INTAS-Georgia, and INTAS-Kazakhstan calls. For the open call, projects for joint research activities must involve at least four research teams: two from different organisations in the NIS and two from different INTAS members. The maximum allowable funding per project is ECU 30,000 multiplied by the number of participating NIS teams, subject to a maximum of ECU 150,000. The 'snag' is that not more than 20% of the total project cost is available to INTAS members. However, you can get a lot of research from the Former Soviet Union for the 80% they receive. There are lots of good ideas there, too!

For networking, INTAS members can get 30% of the total budget, but the funding per team is limited to ECU 10,000, to a maximum of ECU 60,000.

For full information: INTAS is on fax 00 32 2 549 0156. The INTAS Home Page also gives proposal forms etc. at  http://www.cordis.lu/intas/src/ip97wf.htm

Skid-Mounted Fouling Test Facility Available

During the HEXAG meeting at Brunel University, Andy Pitt of ENTEC stated that the skid-mounted test facility currently used to investigate fouling at the ICI Wilton site would become available for other uses early in 1998. The unit has two SHEs, which could of course be replaced by other types of heat exchanger, and is fully instrumented with flow meters, pressure drop measuring instrumentation, and thermocouples, together with appropriate control systems. The outputs of all measuring equipment can be produced in a form ready for computer analysis. The facility is currently handling flow rates of water to 50 m3/h.

If you are interested, please contact Dr. Andy Pitt at ENTEC, Cramlington, Northumberland. Tel: 01670 733777. Fax: 01670 712806, or David Reay . Cost should not be a problem to anyone seriously interested in using the facility at his or her laboratory, or at other sites.