Oakley.qxp 1/7/09 3:40 pm Page 32
EMbaffle
®
Technology – A Major Advance in Heat Exchanger Technology
Heat Exchangers
a report by
Stuart D Oakley
1
and Eric van der Zijden
2
1. Chief Executive; 2. Technical Manager, EMbaffle BV
Of all shell and tube heat exchangers used throughout industry, the With this new EMbaffle technology, the shell-side fluid flows axially
vast majority are still of the segmental baffled type – a design that has along the tubes, but in the vicinity of the baffles the flow area is
stood the test of time over the decades, but that is now being gradually reduced. This creates local turbulence in the flow while breaking up
superseded by a new tube support method that offers considerable the boundary layer over the tubes. The shape of the grid induces a
advantages over the old ways. Over the years, alternative designs have local cross-flow component on top of the longitudinal flow pattern,
been introduced to overcome some of the shortcomings of the which together improve the heat transfer characteristics at the
segmental design, most of which were brought onto the market some surface of the tubes. The break-up of the boundary layer occurs
25 years ago. These included the development of twisted-tube, helix repeatedly at each expanded metal baffle along the length of the
and rod-baffle heat exchangers, but each addressed only some of the heat exchanger, resulting in lower hydraulic resistance while
limitations of the segmental design. With the recent introduction of maintaining higher heat transfer. Pressure loss is effectively
EMbaffle
®
technology, things are now about to change. converted into improved heat transfer and, compared with the
segmental baffle, heat transfer at the same fluid velocity is
Process industries in all market sectors are under pressure to reduce significantly higher.
energy use, limit greenhouse gas emissions and cut costs. An
innovative heat-exchanger technology developed in The Netherlands As a direct consequence of the longitudinal flow on the shell side,
by Shell Global Solutions International BV is now available on the tube vibration in an EMbaffle heat exchanger is effectively
market that addresses these issues, as well as offering significant eliminated, significantly reducing the risk of mechanical damage.
improvements in unit operating performance and efficiency. Known as This absence of cross-flow-induced vibration enables considerable
EMbaffle, this new heat-transfer-enhancing technology is an flexibility in EMbaffle heat exchanger design. For instance, if the
expanded metal baffle that is now being marketed worldwide through particular application demands a low pressure loss, the baffle
EMbaffle BV, a company established in The Netherlands in 2007, with spacing can simply be increased without the risk of introducing
its head office in Amsterdam and regional offices in Houston and tube vibration, although in general EMbaffle spacing is shorter than
Calgary. EMbaffle BV promotes its technology through an in a conventional exchanger.
international network of manufacturing licensees, as well as offering
heat transfer enhancement solutions directly to the market itself. The longitudinal direction of the shell-side liquid in EMbaffle
heat exchangers approaches pure counter-current flow; as a
A significant population of shell and tube heat exchangers result, they can handle lower approach temperatures between the
incorporating EMbaffle technology already exists, with units operating shell-side and tube-side fluid, or deliver higher duty at the same
on refineries and petrochemical plants in Europe, the US and South- approach temperature.
East Asia across a range of applications. A really exciting development
for EMbaffle BV is the recent securing of two contracts to provide Application of EMbaffle Technology
oil/molten salt heat exchangers for the new generation of Initially developed as a potential solution for fouling services,
concentrated solar power stations being built in Spain as part of that EMbaffle technology has been proved in a wide range in
country’s major initiative in renewable energy. It is the ambition of the applications from liquid/liquid and gas/gas to condensing and
company for EMbaffle to become the technology of choice among boiling. In fouling services, for instance in crude pre-heat trains,
end-users and engineering contractors as they seek to reduce capital the dead zones typically found with conventional segmental
and operating costs, as well as to derive material benefits from saving designs reduce the performance of the heat exchanger with an
on energy and emissions. increasing pressure drop during operation. However, with
EMbaffle, due to the longitudinal flow no dead zones are created
Heat Transfer Performance Enhancement behind the EMbaffle, and in-service thermal performance has been
So, what exactly is an expanded metal baffle and how does it deliver shown to improve by more than 50%. This performance
such a significant heat transfer performance enhancement over enhancement can be translated directly into elevated approach
conventional designs? This new shell and tube heat exchanger temperatures to the furnace, resulting in significant energy
technology is based on supporting the tubes in the shell with baffles savings, a reduction in CO
2
and NO
X
emissions and a payback
with an open structure, allowing the shell-side fluid to flow through period of less than six months for new heat exchanger or retrofit
the baffles parallel to the tubes. Although longitudinal flow as such is bundle deployment. In addition, by significantly extending
not new, this type of baffle, together with its shape and engineered operational run times of production units between cleaning as a
profile, results in specific flow characteristics that in many applications direct result of reduced fouling, maintenance schedules can be
lead to optimised heat transfer efficiency. optimised, reducing downtime, increasing throughput and
32
© TOUCH BRIEFINGS 2009
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 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108