A low flow rate equals low pressure drop and high temperature efficiency:
As sludge has a poor heat transfer rate, it is vital to achieve a turbulent flow in a sludge heat exchanger.
In other types of heat exchangers, this is achieved by means of a small pipe cross section and a high flow rate, typically >0.8 m/s.
High velocity equals high pressure drop (all other factors remain the same, double velocity will result in squared pressure drop). High velocity also requires the need for a larger heat transferring area inside the heat exchanger, since the sludge has a considerably lower heat transfer rate than stainless steel, which the heat exchanger is made of. Thus, it takes time and stirring to transfer as much heat as possible inside the heat exchanger.
The patented design of the Westcome® Heat Exchanger, allows the flow to be as low as 0.3 m/s, still being turbulent, due to the inverters of the pipes.
The inverters are designed and placed in the pipe to keep the sludge turbulent with a minimum pressure drop, and the inverters in every new heat exchanger are placed according to flow rate and sludge density (preferably viscosity if the sludge contains unusual components) in order to achieve the best possible stirring/pressure drop rate.
Example of visual evaluation (image below):
Given a flow rate and density (and viscosity), the best pressure drop/stirring rate can be simulated, by changing
parameters such as:
– pipe measurements (cross section)
– inverter plates, size and design.
– inverter plates, distance and angle.
Westcome has considerable experience, based on actual working installations, which serves as data for simulation each new task.