Tank Heating

Tank heating systems from nVent Thermal Management can provide:

  • freeze protection
  • temperature maintenance
  • heat-up and condensation prevention

Tank-Heating.jpg nVent Thermal Management provides these tank heating systems for tanks of small, medium and large volumes.

To optimize your tank and vessel heat-tracing system, nVent Thermal Management offers a wide range of technologies including:

  • Self-regulating heating cables
  • Power-limiting heating cables
  • Constant wattage parallel heating cables
  • Polymer insulated series heating cables
  • Mineral insulated series heating cables
Tank Heating- A Complete Heat Management System Approach

Each technology has specifications which are optimal to fit a vast assortment of heating tracing systems, for both hazardous and non-hazardous areas.

In addition, nVent Thermal Management offers an extensive range of control & monitoring products to complement a complete and reliable heat tracing management system.

Some typical applications for electrical heat tracing of tanks and vessels include:

  • Freeze protection of low and medium viscosity fluids such as water or ammonia.
  • Temperature maintenance for medium viscosity fluids such as oils, bio fuels or resins.
  • Crystallization prevention such as caustic soda
  • Condensation prevention such as fly ash in conical bases of silos or cyclone filters
  • Pre heating of industrial reactors.
  • Specialty applications which include heat-up of high viscosity fluids and agitation applications

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nVent Thermal Management offers tailored solutions with specific benefits to fit your application needs.  There are many technologies to choose from for your specific tank heating application.

Proven Reliable Tank Heating System Technology

For over 30 years, nVent RAYCHEM self-regulating heating cables have proven their reliability and remain the premier self-regulating heating cables in the market. Whilst RAYCHEM polymer series heating cables and associated components can benefit from a long reputation, the nVent PYROTENAX ® branded mineral insulated heating cables (MI) have been the industry standard for over 60 years. nVent Thermal Management can present an extensive reference list for a multitude of applications utilizing different technologies to suit any tank heating application.

Design Flexibility

nVent Thermal Management provides many technologies to fit a variety of temperature ranges.

  • The optimum choice for smaller vessels or sensitive products are the self-regulating heating cables,
  • For large storage tanks, series heating systems are usually the most appropriate solution considering the great savings towards power infrastructure.
  • When high power densities are required or when the associated temperatures exceed the capabilities of any polymeric cable, Mineral insulated series heating systems should be considered.
  • The design is further optimized by the extensive range of control & monitoring products to ensure a reliable heat management system.
Simple & Custom Installation

By offering heating systems consisting of heating cables, the heating systems can be accommodated to fit any shape or size without having to revert to custom made products. Furthermore power densities can easily be adjusted with a same cable type by simply adjusting the spacing of the heating cables where required allowing for product standardization within different applications.

Approvals

The different technologies in our product bag dispose of a wide range of approvals showing compliance to many industrial or national standards including:

  • ATEX
  • RTN
  • IECEx

Our heating systems are approved for use in non-hazardous and hazardous locations.

Self-Regulating Heating Technology

nVent RAYCHEM Self-Regulating Heating Cables (BTV, QTVR, XTV and KTV) can maintain temperatures up to 150°C and are ideal for tank heating when design and installation flexibility are required.

RAYCHEM self regulating heating cables work when:

Self-Regulating

  • Heat is generated as electric current passes through the conductive polymer core between the conductors.
  • As the exposure temperature drops, the number of electrical paths through the core increases and more heat is produced.
  • Conversely, as the temperature rises, the core has fewer electrical paths and less heat is produced.

This property enables the cables to react on local temperature differences to ensure an optimum temperature distribution on the vessel wall and even allows them to be overlapped multiple times without risk of overheating or damages.

The cables

  • Can be cut to length for easier to design and increased installation flexibility.
  • Have an absolute T-rating for maximum safety with respect to hazardous area classification without the need for expensive temperature limiters.

In addition, nVent Thermal Management also offers a wide range of components to realize a state of the art installation, including all accessories to facilitate installation on vessels.


Power Limiting Technology

RAYCHEM Power-Limiting Heating Cables (VPL) feature high power outputs at high maintain temperatures. These flexible heating cables are rated for

Power-Limiting

  • Maintain temperatures up to 235°C
  • Exposure temperatures to 260°C

Power-limiting heating cables are parallel heaters formed by a coiled PTC resistor alloy heating element wrapped around two parallel bus wires that makes an alternating contact with the bus wires. The positive temperature coefficient effect (PTC) of the heating element reduces power output as ambient temperature increases.

The power  limiting cables:

  • Can be overlapped once
  • Can be cut to length which makes for easier design and installation  flexibility
  • Are available in two voltage ratings, 230Vac and 480Vac. The 480Vac versions allow for much longer circuit lengths while keeping all advantages of a parallel heating cable.
  • Have no absolute T-rating (the compliance to the T-classification needs to be proven upon design). They are usually installed with a more advanced control & monitoring system.

In addition, nVent Thermal Management also offers a wide range of components to realize a state of the art installation, including all accessories to facilitate installation on vessels.


Parallel Constant Wattage Technology

RAYCHEM Parallel Constant wattage Heating Cables (FMT & FHT) are a cost effective solution when the requirements of the application are not so critical.

The round flexible heating cables are rated

  • For maintain temperatures up to 230°C
  • Exposure temperatures to 260°C.
  • Constant wattage parallel circuit heating cables have a parallel construction but differ from  power-limiting heating cables
  • They use a Ni-Chrome heating element that does not vary its resistance over temperature.
  • They have a constant power output over temperature.
  • They can be cut to length which makes them easier to install.
  • They do not have an absolute T-rating but the compliance to the T-classification needs to be proven upon design.
  • They are available in fixed wattages per meter, ranging from 10W/m up to 40W/m
  • They exist in two basic constructions:
    • FMT heaters for maintain temperatures up to 150°C and exposure temperatures up to 200°C
    • FHT heaters for maintain temperatures up to 230°C and exposure temperatures up to 260°C.
    • The FHT heaters are also available in a 400Vac version for much longer circuit lengths while keeping all advantages of a parallel heating cable

They are usually installed with a more advanced control & monitoring system and depending on the design, temperature limiters.

In addition, nVent Thermal Management also offers a wide range of components to realize a state of the art installation, including all accessories to facilitate installation on vessels.


Polymer Insulated Series Technology

RAYCHEM XPI Polymer Insulated (PI) Series heating cables can be used when the circuit lengths exceed the ratings of conventional parallel heating cables and a single power source is needed. This technology allows for circuit lengths up to 5km from a single power supply point which makes the most economical choice when high loads are required.

The usage of PTFE in the inner and the outer insulation layer results in a very high temperature resistance of the heating cables and an excellent chemical resistance against the most aggressive products. The production process of the insulation jackets keeps the cables extremely flexible for ease of installation, stripping and simplified termination.

The heating cables are suited for exposure temperatures up to 260°C (intermittent up to 300°C) without polymer degradation or decrease of insulation resistance. Typical power outputs are in the range of 30W/m.

Besides the heating cables, nVent Thermal Management also offers a wide range of components to realize a state of the art installation with a reliable and predictable performance.

Since the performance of a series system is dependent on the total circuit length, applied voltage and electrical configuration (star or delta), any change of the system requires a re-validation of the design.

Depending on the design method (stabilized or control limited) and area of usage (hazardous area or not), the trace heating system might require the installation of:

  • multiple sensors
  • control limiters
  • or additional alarm annunciations

Therefore, series heating systems are typically used with more sophisticated control systems.


Mineral Insulated Series Heating Systems

nVent PYROTENAX® Mineral Insulated (MI) heating cables are series heating cables and are suitable for maintain temperatures up to 600°C and / or exposure temperatures of the heating cables up to 650°C.

Mineral insulated heating cables are the ideal solution when the application‘s temperature and power requirements exceed the capabilities of self-regulating parallel, power-limiting parallel and polymer insulated series heating cables.

Mineral Insulated heating cables consist of one or two conductors embedded in a highly dielectric magnesium oxide insulation surrounded by a metal sheath, optionally served with HDPE or FEP for additional corrosion protection (available for copper sheathed cables only). Because of this construction, MI heating cables provide superior strength in dynamic cut-through and crush tests. Special annealing processes maximise flexibility for ease of on-site handling.

nVent Thermal Management offers single conductor MI heating cables in a multitude of different sheath materials:

  • Copper
  • Cupro-nickel
  • Stainless steel (AISI 321)
  • Inconel 600
  • Alloy 825

The choice of different sheath materials offers the advantage to be able to select the most appropriate jacket material.   Based on environmental parameters (corrosion) as well as the ability to withstand extreme temperatures these sheaths resist process temperatures.  Also to allow higher power outputs since increased power is directly translated in higher sheath temperatures.

Dual conductor MI heating cables are only available in Alloy 825.The use of dual conductor heating cables offers a significant technical advantage when space is limited or when high resistances are required. (e.g. high temperature instrumentation lines, short branches)  Furthermore, installation times are significantly reduced since only half of the length of the heating cable is required compared to an equivalent single conductor heating cable.

Since the jacket materials are metals, connections to cold cables must be made by welding or brazing. nVent Thermal Management offers the possibility to have the joints assembled by laser welding . This technology is available for all:

  • Stainless steel
  • Inconel 600
  • Alloy 825 cables

This allows maximum control of the welding process. The result is a very high quality and extremely reliable joint which allows the heating cables to be used at higher temperatures and / or loadings compared to conventional hand-made silver solder joints.

nVent Thermal Management Provides Single Source Heat Management System for Biodiesel Terminal in Canada
Key Challenges
Biodiesal-Canada-tank.jpg

A Large Global Gas & Oil company decided to expand their biodiesel terminal in Winnipeg, Manitoba, in order to store B100, a pure biodiesel product. As biodiesel has a higher gel point than regular diesel, it requires a more precise temperature.

Solution

nVent Thermal Management provided a complete turnkey heat management system (HMS) for the piping as well as the heat tracing and insulation of the tank. The project was managed out of the Kitchener Services office in Canada and they utilized resources and talent from service centers in Houston and Edmonton to complete the project on schedule.

Products

The project entailed a detailed heat tracing design in combination with insulation on the B100 tank. nVent RAYCHEM XTV heating cable was used for its design flexibility to maintain an accurate temperature; nVent TRACER Trac-Loc, a vertical lock-seam tank insulation system, was used to insulate the tank.

Solution

The comprehensive design was easily integrated within the customer’s timeframe and provided the accuracy required.

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Connection and Protection