No room for wastage

Increasingly, industrial energy users are looking to maximise
energy efficiency and minimise production costs and overheads. Add to
that the increasing requirement for businesses to meet strict energy
targets and there is a real case for reviewing energy use in order to
determine where improvements can be made.

On an industrial and commercial scale, there is arguably no better
place to start improving efficiencies and running costs than by taking a
fresh look at the technologies available in the marketplace and how
these can be utilised to maximise energy efficiency.

While alot can be done by installing modern heating and hot water
technologies to reduce energy usage and lower costs, a case can be made
for the combination of certain technologies to enhance energy efficiency
even further. For example, integrating a Combined Heat and Power module
(CHP) with a steam boiler is an innovative way of utilising the CHP
system’s waste exhaust gas to create a unique arrangement which helps to
increase steam generation efficiency levels.

The combination of steam and CHP

Steam is one of the most widely used commodities for transferring
heat energy. Its use is popular throughout the industry for a broad
range of tasks from mechanical power production, space heating and other
process applications. One of the most common methods of steam
generation is the use of a steam boiler, which operates using three pass
technology.

The steam generated should be available at the client’s point of use
in the correct quantity, at the correct pressure, clean, dry and free
from air and other incondensable gases. In an industrial steam heating
system, the purpose of the generation and distribution of steam is to
provide heat at the process heat transfer surface – this could be using a
heat exchanger.

To enhance boiler efficiency, additional heat can be transferred into
the steam boiler via the waste exhaust gas from a CHP unit. A CHP
module offers a more efficient way to generate heat and electrical power
simultaneously, compared to conventional methods. A typical CHP module
consists of a gas engine, a generator and a heat exchanger system. The
gas engine drives the generator to produce three-phase electrical power,
which feeds in to the main low voltage distribution system where it can
be used locally.

During this process, the heat within the exhaust gases is
produced as a by-product of the usable power and heat generated which,
in a conventional power station, would often be wasted. However, this
exhaust heat generated by a typical CHP module can be re-directed and
may be used in process heating or hot water applications. Through the
use of a waste gas inlet valve, this surplus heat can be transferred to a
specific point of use.

By implementing an innovative fourth smoke tube pass between the CHP
unit and the steam boiler, the surplus heat generated can be driven back
into the steam boiler, thus maximising the energy efficiency of steam
production.

System design

The production of steam was once used for space heating, yet is now
generally more popular for process use. Not only is steam an excellent
carrier of heat, it is also sterile, and thus commonly used in the food,
pharmaceutical and health industries. It is also widely used in
hospitals for sterilisation purposes.

This has meant that companies operating in this sector have generally
had to address the source of electrical power and heat generation in
isolation. As users of the technology will know, the installation of a
steam boiler is very complex, with each steam boiler installation
requiring a bespoke design. Incorporating an innovative fourth pass
technology into any system design between a CHP unit and a steam boiler,
can lead to considerable increases in energy efficiency in comparison
to the conventional, separate electrical power and heat generation. This
will also ensure reduction in CO2 and NOx emissions, providing further
environmental benefits and compliance with the CRC Energy Efficiency
scheme.