ROOF MOUNTED HEAT EXCHANGE UNITS
Model100518/1 Short form for up to 40 cubic meters of digester
Model100518/2 Long form for up to 60 cubic meters of high temperature digester.
Flow 70C - 80C
Return approx 65C
These Practically Green (TM) heat exchangers have proved to be reliable
for over a decade. Designed to be intrinsically safe and highly resistant
to accidental damage, these units have survived being 'run over' by 20 tonne
rotating 'scumbergs' on the surface of the digester, floating due to air
ingress during maintenance, crushing due to water pressure when empty, fouling
with every known make of string / fibre / crust and plastic fertiliser bag.
It IS possible to block these units - once we saw a heat exchanger buried
to three quarters of its height in fine sand because the digester had never
been cleaned - that does prevent heat exchange BIG TIME! Cleaning is easy
- lift them out through the roof or leave them in place and dig out underneath
them with a spade once every 2 years. Better still, design the digester
system correctly in the first place to eliminate or minimise fine sand accumulation.
Operating at high solids reduces the sand deposition.
The heat exchange units are surface treated for continuous operation
in high and low solids digesters with high levels of H2S. The visible parts
above the digester lid surface are solid stainless steel for maintainability
terminating in BSP pipe threads.
For industrial wastes, and dilute wastes we can supply skid mounted, very reliable and easily maintained external tube heat exchangers. These are typically used in sewage works digesters and Centralised Anaerobic Digestion (CAD) plants and come with full instrumentation and pumps packaged for the minimum connection times. Call for a quotation for your site needs. We need to know the type of sludge, the collection and delivery point in the digester, (normally to and from well mixed areas of the digester arranged to minimise short circuiting), the sludge total solids inside the digester, growth plans for increasing sludge total solids, the loading rate of the digester, volume of digester, current and desired temperatures for the digester, insulation levels on the digester, nominal heating capacity required from the heat exchanger. We recommend that for operational reasons the maximum daily feedstock load should be heated in 8-10 hours.