J C Andrews Award Address July 2024: Chris Bloore

A Chemical Engineer in the Dairy industry

Tēnā koutou katoa

I was surprised and delighted to be selected to receive this award established in memory of Massey University’s first Chancellor, Dr John Clark Andrews. With the support of Dr Garth Wallace and Professor Kelvin Scott, they established the Food Technology course at Massey, with Dr Scott as the inaugural Professor. In order to give graduates a professional body to join, they helped establish the New Zealand Institute of Food Science and Technology which was chartered in 1965.

The very first recipient of the J C Andrews award, in 1967, was Dr Garth Wallace. He was an old family friend of my father’s. Garth’s father taught Dad and Garth the art of joinery and furniture making. Garth kept a friendly eye on my progress at the New Zealand Dairy Research Institute once I started work there in November 1971, at first as a holiday job to complete my practical work for my chemical engineering degree and then as a research officer in the milk powder and drying section.

Searching for a career

I got into dairy science and engineering more or less by accident. I grew up in Blenheim and I went to Canterbury University hoping to study physics. Sadly, my lack of study in mathematics required me to repeat both pure and applied maths units. The result was that I graduated with an undistinguished BSc in chemistry. At this point I discovered chemical engineering, and found it was exactly what I wanted to do.

I got direct entry into the Second Professional year, but I had to keep terms in the First Professional year subjects. Now, Second Pro was the last year taught in Imperial units and first Pro was the first taught in metric. I did not understand most of the Second Pro subjects until late in the year when the First Pro teaching caught up.

The direct entry to the Second Professional year left me one vacation practical work session short compared with my classmates, hence the holiday job at the NZDRI.

The milk powder explosion

Upon the retirement of Dr Dick Dolby, a junior vacancy arose and I was offered it. I got to work studying powder flow in the lab and measuring stack losses from cyclones out on spray dryer building roofs. My appointment was part of a significant growth in the NZDRI occasioned by the looming entry of the UK into the European Economic Community. New Zealand dairy farmers were paid only for the fat content of their milk and most of the fat went to Britain as butter which contains 80% fat. There was a big push to develop alternative products to shift fat. The first whole milk powder was exported in 1973. Whole milk powder contains only 26.5% fat, so large tonnages were required. This stimulated a vast expansion in the size of spray drying plants.

…and computer controlled processing

Thanks to another happy accident, I was the first chemical engineer on the staff who had received a course on process control. Back in the very early 1970s, if control was automatic rather than strictly manual it was accomplished by 3 to 15 psi pneumatic controllers fitted with large circular charts on which ink pens traced circles of varying wobbliness. Change was coming, though. In 1972 the DSIR proposed applying minicomputer control to the NZDRI’s Wiegand pilot scale evaporator. The Dairy Board, NZDRI, Massey University, the DSIR and IBM eventually set up a joint milk powder control project and ordered a DeLaval tall-form spray dryer matched in capacity to the Wiegand evaporator. IBM supplied a System 7 computer with a massive 16,000-word memory and a 1-megabyte hard drive. The DSIR installed a great many thermocouples, magnetic flowmeters, pressure transmitters, densitometers, viscometers and other instruments which were duly interfaced to the computer. I was assigned to the project, but because there were no post graduate control engineering courses available in New Zealand, I was sent to the University of Manchester Institute of Science and Technology (UMIST) to do a MSc in the theory and practice of automatic control. The course involved two terms of lectures, exams and two terms of a research dissertation. I left in September 1973 and returned at Christmas 1974 to be greeted by two PhD control engineers from the UK, one from Massey and one from the DSIR. The new spray dryer was being commissioned, and there was plenty of wiring and calibration work to do. In those days multicore instrument cable was not available in New Zealand, and thick bundles of household threecore flex connected all the instrumentation to together. Cable looms were beautifully tied up with waxed brown string. No cable ties in those days.

Throughout this period, I got to know the technologist in charge of the pilot plant, Tony Baucke, very well. He taught me most of what I know of hygienic design and the practical aspects of operating maintaining and cleaning dairy equipment.

For a couple of years, I acted as project manager for the control project. I talked the Institute’s directors into letting me start a PhD using what was then (and may still be) the best controlled and instrumented pilot milk powder plant in the world as my apparatus. Massey University’s Industrial Management and Engineering Department under professor Kelvin Scott provided the academic support. I then headed up a small Applied Mathematics section responsible for experimental design and statistics support, computing, pilot plant instrumentation and control and microprocessor design. Highlights included instrumenting and controlling a 1 tonne per hour Contimab butter maker, and pilot plant casein, whey ultrafiltration and batch cheese operations at the NZDRI. We designed and manufactured thirty effluent monitoring systems for dairy factory drains, eventually licensing the commercial manufacture to EMC.

A travelling trouble-shooter

All during this time I travelled extensively around the New Zealand milk powder industry, trying to find the real problems facing the factories as they tried to cope with increasingly large capacity equipment, the introduction of fluid bed secondary drying, bag filters, more stringent quality requirements and tighter environmental constraints. My journey started with a trip to Northland with my then boss, Dr Dave Woodhams.

I achieved my first control success at Te Puke. One of the two evaporators was being run manually because the controller had stopped working sometime during the previous season. I asked if I could have a look inside the large stainless steel cabinet housing all the electrical and pneumatic equipment. I noticed a nylon air hose flapping around making a hissing sound. I also noticed a spigot on the back of the total solids controller with no air hose. When I attached the hose to the spigot and wired it on tightly, the controller came to life and automatic control resumed. Not magical, but it appeared so.

The Te Puke dryer was a vertical Buflovac unit with 28 cyclones connected in four rows of 7 to a pneumatic transport system. By careful balancing of the pressures between the cyclones I was able to reduce the skim milk powder losses from 3¼ percent to around 1½ half percent. Later I organised panel beating for some of the most damaged cyclones I had ever seen - some were beaten into square, triangular and even once a kidney shape!

Problem solving has been a continuing thread running through my career. Having an outside perspective is really helpful when tracking down the cause of strange behaviour in dairy and food processes.

Process performance management

My introduction to thinking about process performance began at the Picton Freezing works while doing my first three-month practical work placement. They had a new cool store with an ammonia refrigeration plant. The ammonia condenser was a vertical shell and tube unit down on the sea front. Seawater was pumped as a thin falling film down the inside of the tubes while ammonia condensed on the shell side. The temperature of the seawater flowing out the bottom was lower than the temperature of the seawater being pumped in the top. Weird, eh? I noticed that there was a strong updraft in the tubes. It turned out that the evaporative cooling effect of the rising warm air exceeded the heat flow required to condense the ammonia, leaving the cooling water colder than it started. This taught me to look twice at anything I saw to see what else was going on.

Some of the weird phenomena I have encountered include an infant formula evaporator finisher that unhomogenised the concentrate after oil had been successfully homogenised into it. There was an oil slick on the dryer feed balance tank. It turns out that the surface tension around an air bubble is higher than that around an oil droplet. This attracted the fat globule membrane proteins and phospholipids surrounding the oil droplets away to surround the air bubbles arising from a vacuum leak in pipework ahead of the final effect extract pump. I had to wrap duct tape around all the pipework closer than three metres from the pumps to prove the point. Removing the duct tape brought the problem back.

Powder explosions

In February 1989 the Morinaga tall-form spray dryer in Dargaville experienced a catastrophic dust explosion which ripped the chamber from the bustle and removed around half of the long run steel cladding from the steel framed building. I flew up to Auckland and drove to Dargaville to inspect the damage. A day later Ian Peacock and I flew to Copenhagen to discuss a replacement with Niro and Anhydro then flew to Helsinki to talk with MKT. Five days and three nights away and we were back in New Zealand, faxed a report with recommendations and then slept for 24 hours.

This incident generated enough interest for the setting up of a joint working group of NZDRI, the Fire Service, the Insurance council, the Department of Labour and the Dairy Board. The result was the Approved Code of Practice for the Prevention, Detection and Control of Fire and Explosion in New Zealand Dairy Industry Spray Drying Plant. Tony Baucke chaired the committee and I edited the final draft. This got me interested in powder explosions and led to many incident investigations.

An independent Consultant’s life

My wife was accepted for training at the Knox Theology College in Dunedin, so in 1990 I left the NZDRI and our family moved to Dunedin. I set up as a self-employed dairy industry systems consultant. I participated in many evaporator and spray drying commissionings over the next three decades.

In 1999 I moved to Melbourne and spent 18 months as a visiting researcher at Monash University at Clayton and its associated Dairy Process Engineering Centre at Werribee. I taught two semesters of food engineering and rewrote the IChemE dust explosion training course to suit the dairy industry, running many half-day training courses around Victoria. While there I was appointed to the technical working party developing AS/NZS 4745 Code of Practice for Handling Combustible Dusts. This was completed and published in 2004. Since then, I have run over 170 half-day fires and explosions courses in many countries, including New Zealand, Australia, Malaysia, Singapore the USA, Canada and Ireland. Over the past three decades I have spent around one third of my time training in milk composition, evaporation, spray drying and related subjects.

I have worked for insurance loss adjusters on many claims relating to explosions, control system failures, equipment failures and customer complaints about product defects.

I have helped install many NIR in-line standardising systems in cheese and powder plants. This involved solving all sorts of problems related to the way the instrument saw the liquid milk. One example is that of a home-made static mixer that left the milk spinning as it passed the gap between the fibre optic probes in the centre of the 4-inch milk line. The sample tap was on the tube wall. Centrifugal force created a density gradient across the pipe diameter. The fat went to the centre and the skim went to the wall. The fat and protein readings depended on how fast the milk was pumped through the line.

Milk standardising for protein as well as fat became legal following Codex Alimentarius changes in 1999. Every dairy company in New Zealand and Australia began pouring lactose and/or milk permeate into their skim milk and whole milk powders. This reduced the concentrate viscosity, allowing the total solids to be raised. I designed many in-line capillary viscometers for dryers in New Zealand, Australian and the USA so that the total solids could be maximised safely.

Protein standardisation also created a significant problem for the spray dryers. These protein-standardised powders were much stickier. Powder deposits on chamber roofs, walls and cones reduced run lengths and led to browning of the powder and shorter times between chamber washes. It also increased the incidence of dust explosions as self-heating within powder deposits provided an ignition source. I developed a laboratory test for powder stickiness with the help of a 4th year student Adrian Dixon, while at Monash University in 1999. After several prototypes were sent to the Teagasc Moorepark research centre in Fermoy, Ireland, we had a paper published in Milchwissenschaft. This led to the development of sticky line software now used in many countries.

In conclusion

Over the past 53 years I have had the pleasure of visiting well over 200 spray dryers in Australia, Canada, China, Estonia, Finland, France, Germany, Ireland, Malaysia, the Netherlands, New Zealand, Singapore, the UK and the USA. I have also designed several spray dryers, including one jointly with David Platts for New Image.

The dairy and wider food industry has been a great place to work. I’ve made many friends, learnt a lot and had a lot of fun. Thank you all. Nō reira, tēnā koutou, tēnā koutou, tēnā koutou katoa