Gulf Cement Company (GCC) is a leading cement producer in the United Arab Emirates.
Based in Ras Al Khaimah with an installed annual production capacity of 2.5 million
tons cement and 1.3 million tons clinker. GCC is leading regional cement exporter
in the United Arab Emirates. GCC Ras Al Khaimah (U.A.E.) operates 2 cement kilns
- the first one of 4100tpd capacity & the second one of 7500tpd capacity.
The Need
Electrical energy is a significant contributor to the cost of manufacture of cement.
In its endeavour to remain competitive, the cement industry remains pre-occupied
with figuring out measures to reduce energy consumption or the cost of energy. Since
the unit cost of captive generation turns out to be well below that of grid power,
most cement plants prefer to set-up a captive power plant. As an additional measure,
several cement plants have invested in power generation based on the recovery of
heat from kiln & cooler exhaust gases, which would otherwise have been vented to
the atmosphere; so called Waste Heat Recovery Systems (WHRS).
To meet its electrical energy needs and reduce demand on the grid supply or captive
power, GCC decided to invest in Waste Heater Recover system which could also bring
down the burning of fossil fuels. The GCC required advanced WHRS in order to quickly
and efficiently reduce greenhouse gas emissions and attracts CDM benefits.
As a consequence, GCC contracted ThyssenKrupp Industries India Pvt. Ltd (TKII) to
set-up a 35.5MW Waste Heat Recovery based Power Plant utilizing waste heat from
the preheaters & coolers of both kilns and exhaust gas from a gas turbine operating
in open cycle. TKII in turn entrusted Control & Automation (C&A) the responsibility
for design, supply, erection supervision, testing & commissioning of the Electrical,
Control & Instrumentation System for WHRS.
Solutions
C&A was responsible for a complete design, engineering, procurement, supply,
supervision of installation and commissioning of Electrical Power Distribution System,
Instrumentation & Control and DCS system for the WHRS Auxiliaries.
The scope of supply included all the electrical, control and instrumentation equipments
- from the electrical balance of plant to the substation, and from the instrumentation
and field devices to the distributed control system, across the entire delivery
chain.
This involved detail layout engineering pertaining to electrical equipments, cable
trays, lighting fixtures & earthing & lightning protection system based on the existing
plant layout & the GA drawings of the various plant structures, i.e. STG building,
boiler structures, electrical rooms On the electrical side, C&A designed, engineered,
supplied Generator Power Transformer, MV switchboards, LV Power Switchgear and protection
system to ensure reliable and uninterrupted power supply from and to the power grid.
During design and planning stage, the space availability on site was a major challenge.
The situation was challenging, due to this being a brown-field project, C&A was
responsible to ensure the accommodation of equipments in existing available space.
The responsibility was also to ensure modification in existing switchboards to facilitate
interface with the existing power distribution system, understand existing as well
as new load, P&IDs and plant Lay out.
However C&A team adopted innovative engineering strategies to overcome these
challenges, and ensured installation of equipment did not constrain in any way.
In addition to the electrical package, C&A was also responsible for complete
design/sizing of a Distributed Control System (DCS), development of application
software to control & monitor the entire WHRS operation.
C&A provided DCS to maximize WHRS efficiency and reliability through the automation,
integration and optimization of the entire plant. The system handles some 400 I/Os
for each WHRS it and 600 I/Os for the common system, including remote I/Os for cooling
water, auxiliary cooling water, cooling towers and other plant components.
In this project, C&A also implemented Steam & Water Analysis System (SWAS),
covering supply of Sensors & Transmitters for measurement water of level, temperature,
pressure / differential pressure along with process hook-up hardware, control valves
for feed water to condensate flow to the boilers, to provide exact precise measurements
of critical parameters and analysis of steam & water from 24 locations in the WHRS
System.
C&A The Waste Heat Recovery System encompasses :
- 2 boilers for each kiln :
- PH Boiler: Horizontal boiler with vertical tubes for uniform dust disposal -for
heat recovery from preheater exhaust gases
- AQC Boiler: A vertical boiler with horizontal tubes -for heat recovery from cooler
exhaust gases
- 1 HRSG for heat recovery from the exhaust gases from a Gas Turbine
- 1 Steam Turbine of 35.5MW rating
- Boiler Feedwater & Deaerator system
- Steam s ystem
- Condensate system
- Water teatment plant
- Cooling water system
- C&A provided an integrated , E,C&I (electrical, control and instrumentation,) solution
for the entire project, including medium and low-voltage switchgear, motor control,
protection system, inverters, and a state-of-the-art distributed control system
(DCS)
The Result
The system was commissioned & synchronized with the grid in Aug 2013 and is working
satisfactorily. Apart from the monetary benefit involved, WHRS is playing vital
role in energy conservation, as GCC do not need any additional fuels to generate
electricity and hence directly help conserve fuels and reduce overall carbon emissions.
The WHRS at GCC is expected to lead directly to a reduction a tonne of carbon dioxide
(CO2) emissions per annum.