1 ．Air Compressor Set of the Fluidized Catalytic Cracking Unit of a Refinery
To meet the needs for energy recovery, a main air blower set of the fluidized catalytic cracking unit of a refinery is usually a “three machine set” or “a four machine set”, installed with one flue gas turbine-expender, together with one standby motor-driven main air blower, two turbochargers, and one rich gas compressor. The main air blower set is usually an axial-flow compressor, and the standby main air blower is of centrifugal type. Generally, the main air blower set of the “three machine set” comprises of a flue gas turbine-expender, an axial-flow air blower, and a motor/generator , while the main air blower set of the “four machine set” comprises of a flue gas turbine-expender, an axial-flow air blower, a turbine, and a motor/generator . The control and protection of the sets; installation of an automatic self-protection system (including anti-surge control, speed regulation control, load control and decoupling control, various oil pressure controls); monitoring of bearing temperature, axle vibration and axial displacement supervision; monitoring and control of main machine and auxiliary machine technical parameters; and order control of startup mode - operation mode – safety operation mode – stand-by mode; and interlock logic protection (ESD) commonly share a system of integrated turbine compressor control (ITCC). Regarding the technical process, regenerator pressure may be introduced to effect split control by three ranges to separately control the inlet butterfly valve, bypass valve and double acting slide valve of the flue gas turbine-expender. The purpose of split range control is to maximize recovery using the flue gas energy. Regarding the process of using regenerator pressure to control the open width of the inlet valve of the flue gas turbine-expender, the protection of the speed regulation machine should also be considered. The common practice is to make low value selection between the output of speed control device and pressure control device. The control of the wet gas compressor is usually exercised by controlling the rotating speed of the turbine based on the inlet pressure of the compressor. Meanwhile, a stable operation of the wet gas compressor set may be effected by applying decoupling control between anti-surge control and speed-regulation control.
The ITCC system usually comprises of a main rack plus two to three extension racks, together with two sets of operation stations with mutual backup (MMI), and adopts redundant communication. It uses engineering stations for programming or breakdown diagnosis, applies MODBUS communication cards for communication with DCS, and applies OPC for communication with the management network of the whole plant.
2 ．Air Compressor Set of the Reforming - Hydrogenation Unit in a Refinery
Of the air compressor set of the reforming - hydrogenation cracking unit of a refinery, the turbine-driven circulation-hydrogenation compressor is usually of centrifugal type, and the fresh hydrogen compound compressor is motor-driven. The driving machine of the centrifugal compressor is generally a turbine. The fresh hydrogen compound compressor is an electric driving machine. Of the whole set of facility installed, the anti-surge control of the centrifugal compressor; speed regulation control, load control and decoupling control of the turbine; power control of the motor; lubricant station control; monitoring of bearing temperature, axle vibration and axial displacement; monitoring and control of main machine and auxiliary machine technical parameters; logic order control of the startup mode - operation mode – safety operation mode – stand-by mode; and interlock logic protection (ESD) commonly share a system of integrated turbine compressor control (ITCC). As the control target of the circulation-hydrogenation compressor is outlet pressure, the pressure control is usually cascaded to the speed control. The multi-stage centrifugal compressor also adopts a stage-by-stage return control plan, which is somewhat similar to that of a reciprocating machine. Split range control and low value selection is commonly adopted under such plan. To perform split range, selection, linear amplification and logic in such an electronic control device is not so complicated as in electricity type II and type III separation meters in the past. The ITCC system usually comprises of a main rack plus two to three extension racks, together with two sets of operation stations with mutual backup (MMI), and adopts redundant communication. It uses engineering stations for programming or breakdown diagnosis, applies MODBUS communication cards for communication with DCS, and applies OPC for communication with the management network of the whole plant.3 ．Compressor Group of Medium/Large Fertilizer Units
Of the medium/large fertilizer units of a fertilizer plant, the compressor which is installed may differ with the types of raw materials. A compressor with coal as material may comprise of one synthetic gas compressor, one ammonia refrigeration compressor and one carbon-dioxide compressor. A compressor with oil as material may comprise of one air compressor, one synthetic gas compressor, one ammonia refrigeration compressor and one carbon-dioxide compressor. A compressor with natural gas as material may comprise of one air compressor, one natural gas compressor, one synthetic gas compressor, one ammonia refrigeration compressor and one carbon-dioxide compressor. Turbines are used as drivers for all of the compressors except for those with natural gas as raw material, which are driven by gas turbines. The anti-surge control of all compressors; speed regulation control, performance control, load allocation control, and extraction control of gas turbines; lubricant station control; monitoring of bearing temperature, axle vibration and axial displacement, monitoring and control of main machine and auxiliary machine technical parameters, order control of the startup – operation – stand-by; and interlock logic protection (ESD) commonly share a system of integrated turbine compressor control (ITCC). Based on the design of a turbine and its application requirements, an extraction control device is usually installed and low-pressure steam is produced through single or dual extraction. There are two kinds of turbines, namely condensing turbines and backpressure turbines. The ITCC system usually comprises of a main rack plus two to three extension racks, together with two to three sets of operation stations with mutual backup (MMI), and adopts redundant communication. It uses engineering stations for programming or breakdown diagnosis, applies network cards for communication with the computer network of the whole plant, applies communication cards for communication with DCS, and applies OPC for communication with the management network of the whole plant.
4 ．Compressor Group of Air Separation Unit with a Capacity of over 3000M3/H
Generally, an air separation unit comprises of one air compressor, one nitrogen compressor, one oxygen compressor and one expander. Most of them are driven by motors and some by turbines. The anti-surge control of all compressors; speed regulation control, performance control, and extraction control of the turbines; lubricant station control; monitoring of bearing temperature, axle vibration and axial displacement; monitoring and control main machine and auxiliary machine technical parameters, order control of the startup – operation – stand-by; and interlock logic protection (ESD) commonly share a system of integrated turbine compressor control (ITCC). Based on the number of points, the ITCC system usually comprises of a main rack plus one or two extension racks, together with two sets of operation stations with mutual backup, and adopts redundant communication. It uses engineering stations for programming or breakdown diagnosis, applies network cards for communication with the computer network of the whole plant, applies communication cards for communication with DCS, and applies OPC for communication with the management network of the whole plant.
5 ．Compressor Group of an Ethylene Unit with a Production Capacity of over 110kt/a
There are usually three kinds of compressors for the ethylene unit of a refinery with a production capacity ranging from 110kt/a to 900kt/a, namely cracking gas compressor, ethylene compressor and propylene compressor. The drivers are turbines. The anti-surge control of compressors; speed regulation control of turbines; performance control of compressor sets; lubricant station control; separator liquid-level control; monitoring of bearing temperature, axle vibration and axial displacement; monitoring and control of main machine and auxiliary machine technical parameters; order control of the startup – operation – stand-by; and interlock logic protection (ESD) commonly share a system of integrated turbine compressor control (ITCC). Generally, the rotational speed of a turbine is adjusted in accordance with the inlet and outlet pressure or inlet and outlet flow rate of the compressors. Meanwhile, decoupling control is performed among the anti-surge control, performance control and speed regulation control. The ITCC system usually comprises of a main rack plus two to three extension racks, together with two or three sets of operation stations with mutual backup, and adopts redundant communication. It uses engineering stations for programming or breakdown diagnosis, applies network cards for communication with the computer network of the whole plant, applies communication cards for communication with DCS, and applies OPC for communication with the management network of the whole plant.
 
6 ．Compressor Groups of Synthetic Rubber Unit
Generally, a synthetic rubber unit of a petrochemical plant comprises of one ethylene compressor, one propylene compressor and chloromethane compressor. All of them are driven by turbines. The anti-surge control of the compressors; speed regulation control, performance control, and extraction control of the turbines; lubricant station control; monitoring of bearing temperature, bearing vibration and axial displacement; monitoring and control of main machine and auxiliary machine technical parameters; order control of the startup – operation – stand-by; and interlock logic protection (ESD) commonly share a system of integrated turbine compressor control (ITCC). Generally, the rotational speed of a turbine is adjusted in accordance with the inlet and outlet pressure or inlet and outlet flow rate of the compressors. Meanwhile, decoupling control is performed among the anti-surge control, performance control and speed regulation control. The ITCC system usually comprises of a main rack plus one to two extension racks, together with two sets of operation stations with mutual backup. It uses engineering stations for programming or breakdown diagnosis, applies network cards for communication with the computer network of the whole plant, applies communication cards for communication with DCS, and applies OPC for communication with the management network of the whole plant.
7 ．Circulation-Hydrogen Compressor Group of Aromatics Unit
Generally, the aromatics unit of a petrochemical plant comprises of three circulation-hydrogen compressors. The circulation compressor is a turbine-driven centrifugal compressor and the fresh hydrogen compressor and regenerated hydrogen compressors are motor-driven piston compressors. The anti-surge control of the compressor set; speed regulation control, performance control, and extraction control of the turbines, lubricant station control; monitoring of bearing temperature, bearing vibration and axial displacement; monitoring and control of main machine and auxiliary machine technical parameter, order control of the startup – operation – stand-by; and interlock logic protection (ESD) commonly share a system of integrated turbine compressor control (ITCC). Generally, the rotational speed of a turbine is adjusted in accordance with the inlet and outlet pressure or inlet and outlet flow rate of the compressors. Meanwhile, decoupling control is performed among the anti-surge control, performance control and speed regulation control. The ITCC system usually comprises of a main rack plus one to two extension racks, together with two sets of operation stations with mutual backup. It uses engineering stations for programming or breakdown diagnosis, applies network cards for communication with the computer network of the whole plant, applies communication cards for communication with DCS, and applies OPC for communication with the management network of the whole plant.
8 ．Compressor Group of Alkaline Unit with a Production Capacity of 600kt/a
Generally, the unit of an alkaline plant with a production capacity of 600kt/a comprises of six carbon-dioxide compressors and two vacuum air blowers, all of which are driven by turbines. The anti-surge control of the compressors and air blowers; speed regulation control, performance diagnosis control, and extraction control of the turbines; lubricant station control; monitoring of bearing temperature, bearing vibration and axial displacement; monitoring and control of main machine and auxiliary machine technical parameters; order control of the startup – operation – stand-by; and interlock logic protection (ESD) commonly share a system of integrated turbine compressor control (ITCC). Generally, the rotational speed of a turbine is adjusted in accordance with the inlet and outlet pressure or inlet and outlet flow rate of the compressors. Meanwhile, decoupling control is performed among the anti-surge control, performance control and speed regulation control. The ITCC system usually comprises of a main rack plus two to three extension racks, together with two sets of operation stations with mutual backup. It uses engineering stations for programming or breakdown diagnosis, applies network cards for communication with the computer network of the whole plant, applies communication cards for communication with DCS, and applies OPC for communication with the management network of the whole plant.
9 ．Blast Furnace Power Recovery Turbine (BPRT) and Auxiliary Systems of an Iron and Steel Works
Generally, the power recovery unit of the BPRT and its auxiliary system should regulate the synchronization rotational speed and load control of the recovery generation set. The monitoring of bearing temperature, bearing vibration and axial displacement; monitoring and control of main machine and auxiliary machine technical parameters; order control of the startup – operation – stand-by; and interlock logic protection (ESD) commonly share a system of integrated turbine compressor control (ITCC). The ITCC system usually comprises of a main rack plus one to two extension racks, together with a set of operation stations.
10 ．Turbine – Generation Set
Regarding general condensing and backpressure extraction turbine sets, the functions that ITCC can perform are set out below:
01．Both cold and hot startup modes are available. The rotational speed of the turning can be automatically increased or reduced to a fixed speed, or a mode of main stream valve manual startup can be directly applied.
02．The rotational speed can be reduced or increased manually to fulfill synchronization.
03．Rotation speed closed-loop regulation function (automatic warm-up and automatically passing critical rotational speed)
04．Electrical power closed-loop regulation (automatic load-carrying )
05．Primary frequency control limit function (manual/automatic switch)
06．Extraction automatic closed-loop regulation and heat and power co-regulation and static automatic adjustment.
07．Switch between the mode of fixing power based on heat and fixing heat based on power
08．Capable of receiving remote load instructions and remote load variation rate instructions (switching)
09．The system has external signal intervention and preservation function (switching)
10．Power limit function
11．Communication interfaces enabling data communications with other systems
12．Super-speed text and governing valve tightness test function
13．Sound self-diagnosis functions
14．The functions of the system are operated with an external keyboard through I/O channel.
In the case of the control system of a set with capacity below 50 MW, depending on the number of points, the ITCC system generally comprises of two racks and an operation station (MMI), together with an operation desk. It uses engineering stations for programming and breakdown diagnosis, applies network cards for communication with the computer network of the whole plant, and applies the communication visibility device developed by TRICONEX for communication with DCS.
|
