DuroShell – Plate-and-shell made tougher
In the power industry, shell-and-tube heat exchangers have long been used in a variety of demanding positions that gasketed plate heat exchangers cannot manage. But space is often a scarce resource in power plants, and bulky shell-and-tubes require a lot of it – not to mention a large capital investment.
Fortunately, the time for change has come. Alfa Laval DuroShell is a plate-and-shell heat exchanger that has been specially engineered with a robust, compact and lightweight design. It ensures more reliable temperature regulation with cost-effective performance and a smaller footprint.
Uptime is critical in a power plant. Keeping the entire plant online means that every piece of equipment needs to perform as expected, at all times. This is especially true of heat exchangers that perform tough duties ranging from steam condensing to recirculation heating. To minimize unplanned downtime in power operations, Alfa Laval DuroShell offers reliable performance thanks to exceptional fatigue resistance and fouling prevention.
As flexible as it is strong
Compact and exceptionally durable, DuroShell creates new possibilities through its unique strength and efficiency. Able to work with liquids, gases and two-phase mixtures, including a wide range of aggressive media, it stands out among heat exchangers in its duty range. DuroShell handles pressures up to 100 barg (1450 psig) in compliance with PED and ASME, along with temperatures as high as 450°C (842°F).
Built for your application
DuroShell is fully welded and gasket-free, with internal features that make it still more robust. Plates are available in 316L stainless steel or titanium, while the pressure vessel itself can be built in 316L stainless steel or carbon steel. Three different sizes are possible, with heat transfer surfaces ranging 2–235 m2 (21.5–2530 ft2) in area.
Why make the change from shell-and-tubes?
Shell-and-tube heat exchangers have long been the choice for power plants when it comes to working with two-phase mixtures and aggressive media. While they can handle higher pressures and temperatures than gasketed plate heat exchangers, shell-and-tubes are generally bulky, expensive and unsuited to the most demanding duties. Plate-and-shell heat exchangers offer a smarter solution. And with unparalleled efficiency and durability, Alfa Laval DuroShell is the smartest solution of all.
Save on space, save on cost
For power plants that face major space limitations, DuroShell offers important advantages compared to traditional shell-and-tubes. In addition to featuring an exceptionally compact design, DuroShell provides the unique capability to condense steam and subcool condensate in the same unit. This enables higher levels of production in a fraction of the space.
As a lightweight alternative with a smaller footprint, DuroShell also translates to a lower investment cost. And higher efficiency with reduced maintenance requirements ensures a lower total cost of ownership throughout the equipment’s lifecycle.
Discover the benefits
Learn how you can maximize uptime, cut cost and increase capacity by installing Alfa Laval DuroShell.
Or find out the reasons why your operation would benefit from switching from shell-and-tubes.
5 reasons to make the switch from shell-and-tubes
Make a change to increase your capacity
A heat exchanger for increasing capacity in power plants
Make a change to cut costs
A heat exchanger for cutting power plant costs
Make a change to maximize uptime
A heat exchanger to maximize power plant uptime
Heat exchangers fulfil a number of critical positions in the power industry. And they are increasingly being called on to provide greater efficiency under more demanding conditions. Durable and compact, Alfa Laval DuroShell saves space while creating new process possibilities.
Boiler feed water heater
Preheating boiler feed water using heat from steam extracted between turbine stages helps increase the overall efficiency of a power plant.
DuroShell is well suited for this type of duty. It's easy to operate and control with traditional liquid-level control systems. The close temperature approach ensures feedwater is heated as much as possible.
DuroShell is compact with superior thermal efficiency. It is up to five times smaller than a comparable shell-and-tube unit, resulting in lower costs for equipment and installation structures. It further reduces installation space and costs as it can perform condensation and subcooling in one unit.
District heat condensing
Power plants around the world have found a new source of income by selling their waste heat to district heating networks. Instead of cooling off low grade heat in cooling towers, heat is used for district heating, adding revenue.
Maximum heat recovery
A DuroShell heat exchanger can be configured to operate with a very small temperature approach and perform condensation and subcooling in one unit. This maximizes heat recovery and minimizes investment costs. DuroShell recovers more heat and only takes up a fraction of the space compared to a bulky shell-and-tube.
DuroShell offers attractive payback times compared to shell-and-tube heat exchangers when used in Organic Rankine Cycle (ORC) applications. It can be used as a reboiler and as a condenser.
DuroShell's short heat transfer ensures a low pressure drop, which minimizes pumping needs. Its heat transfer capabilities result in a compact unit and allow for condensing the vapour and subcooling the condensate in the same unit. This saves installation costs and prevents flash gas from forming downstream.
Fuel gas heater
Preheating liquid boiler fuel is important for ensuring optimum boiler performance. It lowers fuel viscosity for more even distribution and increases flammability.
Preheating is often done using an electric heater. A more economical way is to use waste heat, such as low pressure steam or hot condensate.
DuroShell offers a perfect option for this duty. Thanks to its outstanding efficiency, most of the waste heat is transferred to the fuel stream, and the highly turbulent flow minimizes fouling and maintenance needs for greater uptime.
Gland steam condenser
DuroShell offers strong benefits when used as a gland steam condenser.
Firstly it is very compact thanks to its high heat transfer efficiency, resulting in low installation costs.
Secondly it uses less cooling water than a shell-and-tube heat exchanger due to its ability to operate with crossing temperatures and its small temperature approach.
These benefits quickly add up to substantial savings in large power plants with multiple gland steam condensers.
DuroShell is a good choice for many different auxiliary positions in a power plant. It's a natural choice for every duty where fatigue resistance, durability, high heat transfer and compact size are important factors.
One example is boiler blowdown coolers. These heat exchangers are subject to rapid, fatigue-inducing temperature changes.
DuroShell was designed for the highest possible fatigue resistance and handles temperature-induced fatigue up to twice as well as other types of heat exchangers.
DuroShell's compact size ensures low installation costs and easy installation.
Swedish renewable energy company
More uptime, reduced energy costs and better compliance with environmental regulations at the Jämtkraft Lugnvik combined heat and power plant.
Increased efficiency for French power plant
A French energy company installed DuroShell as a boiler feedwater preheater in its combined-cycle power plant and increased overall plant efficiency with 4%.
Power plant steam condenser
Alfa Laval DuroShell was the perfect solution for the French power plant that needed to reduce its footprint and increase its steam turbine efficiency.
Air preheater in a combined cycle power plant
By using DuroShell instead of shell-and tubes, the power company gets a very compact solution that was easy to install.
Boiler feedwater preheating
The compact size and high thermal efficiency were the main reasons for the company to choose DuroShell.
How to minimize fatigue problems in plate-and-shell heat exchangers
Increase uptime in positions with fluctuating temperatures or pressures.
Optimized flow distribution and fatigue resistance
Patented design enables improved fluid distribution, mechanical strength and unparalleled fatigue resistance
Robust and efficient performance
A patented plate pattern optimizes thermal efficiency with improved fatigue resistance, flow distribution and mechanical strength
Less weight and added reliability
Alfa Laval's unique CutWing plates enable multipass within the shell, making the unit more compact and easier to install, since no external piping is required
Talk to an expert
We will be happy to discuss the benefits a DuroShell can bring you and show how we can help improve your operation.
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