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Emergency shutdown device (“ESD”)
ESD is an automatic, independent and static integrated control system. It is usually used to reduce the rate of accidents in hazardous production processes such as explosion and fire, and to protect critical production equipment. It is used in industries where protection of assets and human lives are of a particular concern.
As a safekeeping system, ESD overrides all other production control systems and is responsible for monitoring any unusual changes in critical indicators. As ESD has static characteristic, it will not interfere with production systems when the overall production is in normal operation. However, when certain critical reference indicators exceed the preset thresholds, ESD will take the necessary actions so as to prevent the outbreak of accidents and minimise losses. Such actions may involve systematically shutting down certain portions of the production process. The use of ESD reduces the chance of having to shut down the entire production process during abnormal conditions which may be costly. Currently, the Group’s ESD is mainly applied in the petrochemical, oil and gas and chemical industries. ESD of the Group comprises advanced hardware based on Triconex’s triple modular redundant (“TMR”) technology and the Group’s propriety software.
Systems with TMR technology have three main control processors which work simultaneously. When one of the main control processors malfunctions, the other two main control processors will automatically takeover all the control functions in the system, such that the control process will not be interrupted.
TMR technology enables high fault tolerance and improves the efficiency of safety and critical control system by utilising a two out of three voting method to achieve a reliable monitoring of the critical production facilities. In a TMR configuration, each of the three main control processors gathers information from the input modules and together performs two out of three voting on the data. If the data do not unanimously agree with each another, two consistent data out of the three will be voted as the correct value. Voted input state results are then transferred to the output subsystem via fault tolerant data communications channels. Each output block then performs output voting on the triplicate output data. This distributed voting technique ensures the highest level of data integrity.
Fire and Gas Systems (“FGS”)
The Group’s integrated FGS offers customers a comprehensive fire and gas safety solution for industries that require a high level of fire prevention standard. FGS is a safety system connected with every fire detector, gas detector and other equipment to ensure the relative equipment are operating properly. FGS also sends out control signals to automatic fire prevention devices.
The Group’s FGS comprises Triconex’s advanced hardware based on TMR technology and the Group’s propriety software. It is usually used in relatively high risk industries such as oil and gas and petrochemical industries.
FGS has a self-diagnostic function that can diagnose faults in the system. It also has an electric circuit testing function that can perform real-time detection of open circuit and short circuit conditions of field equipment. It also has a dedicated uninterrupted power source with reserve power supply that can guarantee reliable power supply in case of accidents.
FGS is an integrated system for both fire alarm and gas (combustible and toxic) detection. FGS is usually connected with other safety systems and fire protection facilities as a network to provide a comprehensive fire and gas protection solution.
System components can be tested without disruption to routine facilities operations or system interruption. Upondetection of alarm condition:1) Audible and visual alarms register in supervisory station triggering annunciator beacons and horns.2) Visual alarms identify type and location of activated sensing device.3) Self-monitoring and supervised inputs/outputs detect faults affecting operation of system.4) Fault detections are alarmed at supervisory station.5) Signals from fire detection system initiate operation of fire-fighting equipment and plant shutdown.
Integrated turbine and compressor control (“ITCC”)
ITCC is an integrated industrial process control system that provides logic control and regulates various functions including air compression, volume of airflow, temperature control and ignition control. ITCC is used in turbine and compressor machineries that are core or critical equipment in the production process of oil and gas, petrochemical, chemical, iron, steel, and electricity generation industries, such as electricity generators, refrigeration machineries and air compression machineries.
Since ITCC is usually used to control the core or critical equipment, the system is required to be accurate, reliable and responsive. If a production plant uses several separate control systems to control the major equipment used in production, the disadvantages are: (i) the coordination among these separate control systems may be limited, (ii) the responsiveness will depend on the machinery with the slowest response speed, and (iii) it would be relatively difficult to perform equipment maintenance and would cause high maintenance fee. As such, the ITCC of the Group is an integrated control system which combines Triconex’s advanced hardware based on TMR technology and the Group’s propriety software. It uses one system to control multiple core or critical parts of the production process, so as to solve the problems with using several separate control systems.
ITCC can perform different critical control functions in one system such as: i) turbine speed regulation, ii) anti-surge control (i.e. protecting the compressors from surge), and iii) emergency shutdown, through its integrated function. ITCC are able to closely adjust and coordinate different control functions in one system, and therefore can reduce cost and enhance reliability of the production facilities in many processing industries.
ITCC can fulfill the following control objectives including:
i) overall control of the compressor system;
ii) maximise compressor efficiency;
iii) accurately determine how close the compressor is to surge and generate the appropriate anti-surge output;
iv) maintain compressor and turbine operation within the safe operating parameters defined by the manufacturer;
v) optimise compressor operation by minimising variable overshoot from critical compressor and process limitations. Permit an adequate but not excessive recycle flow;
vi) maximise process stability through real-time control loop decoupling techniques between compressor anti-surge, performance, steam extraction and turbine speed control loops. On multiple section compressor applications, anti-surge loop decoupling is also provided;
vii) maximise energy efficiency with the subject compressor network (parallel or series compressor applications only) by distributing the total load so as to maintain each compressor at the same relative distance from surge, thus avoiding unnecessary recycling or blow-off at times of reduced throughput;
viii) minimise operator intervention during process status changes through the use of standardised mode switching schemes for startup, shutdown, and purging sequences;
ix) machinery over-speed protection;
x) detect failure of the anti-surge control and generate an appropriate protective output; and
xi) provide uninterrupted control in the event of hardware failures.
 Railway interlocking system (“RIS”)
RIS is important for railway transportation. RIS is located in a particular railway station to regulate the railroad switches, so as to ensure that trains will go through the right railroad switches safely, preventing collision between trains. It is based on the railway transportation plan of the station to direct the train to stop or to go through the right track when reaching a railroad switch. RIS will lock the railroad switch when a train passes by. After the train reaches its destination, the railroad switch will then be unlocked. RIS of the Group are mainly used in the chain mode railway stations of the iron and steel industry and other freight transportation.
The technological requirements of RIS are different from the other safety and critical control systems of the Group. Therefore the Group has a specialised team in RIS which comprises separate personnel including sales, technical and production staff.
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