Rosenblad Design Group, Inc.
provides multiple effect evaporators that have weathered years of
rigorous testing with proven performance and stability.
With high heat transfer coefficients, the AXERO™
evaporator makes maximum utilization of the available temperature
differential thus allowing more effects in a fixed temperature
range. Also, positive circulation provides for one hundred percent
turndown capability with stable operation.
Other benefits of RDG'S evaporators
include the following recent technological breakthroughs:
The radial design is Rosenblad Design Group's standard for
larger evaporators. The main benefits of this innovative technology
are as follows:
GEOMETRY - A cylindrical element package is installed in a
cylindrical vessel. This ensures uniform flow distribution and
makes the most effective use of the available space.
PRESSURE VESSELS - All pressure chambers now become cylindrical
vessels. These are much superior pressure vessels since they
minimize or eliminate large flat surfaces and sharp corners with
associated stress concentration.
ACCESS - All radial evaporator bodies provide walk-around access
to all internals for inspection and service.
WASHING - High-pressure washing is not typically required as
routine maintenance. The gap between the elements is made bigger
than for a rectangular or square configuration, which makes them
less sensitive to fouling and plugging. This is important at higher
The stacked design for multiple effect evaporator systems was
first incorporated in 1977. The objective of the stacked design is
to simplify the system, minimize vapor ducting, and, in some
instances, eliminate transfer pumps and controls. Some of the
realized benefits are:
- Reduces civil works and foundation costs.
- Reduces building size and costs.
- Reduces the number of vessel heads and control loops.
- Reduces cost of piping, ducting and supports.
- Minimizes pressure drops.
- Allows space for future modifications and expansions.
Bottom Vapor Entry
Bottom vapor entry is used primarily for condensate segregation
with countercurrent flow of condensing steam and outgoing
condensates. In this design, more than 85% of the incoming methanol
content and associated COD can be concentrated in a less than 10%
stream of the entering vapors. This means smaller flows of foul
condensate to the steam stripper and cleaner contaminated
Additional benefits of bottom vapor entry include the
- Elements can be bottom supported from the steam inlet
- Eliminates large steam headers and vapor ducts at the top of
- Reduces size of body diameters.
- Creates better entrainment separation