SURVIVAL EVEN in the face of diversity
15 Jan 2000
It has been around 60 years since the first plate heat exchangers were developed, but their usage shows no sign of declining. In fact the opposite is happening. In 2005, total revenues in the European heat exchanger market are forecast to increase to £2.7billion, according to a new study by Frost & Sullivan, the international marketing consultants.
The report has found that the decline in raw material costs, the use of more exotic raw materials, improved price/performance ratios and ongoing product improvements are factors fuelling sales in the European market.
Increasingly stringent legislation regarding wastewater monitoring and volatile organic compounds is also expected to drive demand in heat exchanger markets, reports Vicky Whiting, research analyst at Frost and Sullivan. But Whiting also notes that while the market for heat exchangers is well established and fairly mature, the number of significant technological innovations is very limited. This is where the manufacturers beg to differ.
Old dogs, new tricks
Even Alfa Laval, pioneers in the early days of heat exchange development, concedes that the plate heat exchanger is not a novel idea. But Peter Rose of Alfa Laval states that like all basically good ideas, age seems only to add to their versatility.
`In fact,' says Rose, `there have been more significant advances over the last few years than the plate heat exchanger experienced in its first 40 years.'
The switch from continuous to batch processing demand requires equipment that is compact, versatile and easily or automatically cleaned and maintained. This is not a scenario in which the traditional shell and tube exchanger fits very comfortably, says Rose. The shell and tube is good at withstanding very high temperatures and pressures but tends to be less efficient at actually transferring heat. It also occupies a lot of space and can be expensive to install, maintain and clean. In contrast, the plate exchanger is simple and modular.
Nevertheless, shell and tube heat exchangers achieved the largest revenue share of 37.8 per cent in the European market in 1998. Market growth in plate heat exchangers can be attributed to replacement of shell and tube and other tubular exchangers, according to Frost & Sullivan.
A number of process specific plate exchangers from Alfa Laval are available. Where two fluids would produce a hostile reaction if accidentally mixed, there is a double walled exchanger that leaves any leakage outside the unit. For highly corrosive media, graphite plates can be used, while for intense pressure and temperature, a fully welded exchanger is available.
Diversity does seem to be the key. HRS Heat Exchangers (Spiratube) has been aware for some time of what it sees as the inadequacy of existing designs used for processing very viscous fluids. To satisfy this market, the company has developed a new generation of scraped surface heat exchanger. By combining a much greater surface area than is normally available in a scraped surface exchanger with a new reciprocating action, flexible scraped surface exchangers can now be used for a wide variety of applications.
