odor control system scada system operation manual - stockton odor... · plc 24 – odor control...

PLC 24 – ODOR CONTROL SYSTEM

SCADA SYSTEM OPERATION MANUAL Revision 1.0

May 5, 2006

Meyer Control Corporation Stockton RWCF WW32 / WW39 CH2M Hill / OMI – Thames Water

PLC 24 – ORDOR CONTROL SYSTEM

SCADA SYSTEM OPERATION MANUAL Revision 1.0 May 5, 2006

Table of Contents 1 Introduction............................................................................................................................................................................................................ 4 2 Revision History .................................................................................................................................................................................................... 4 3 PLC System Overview........................................................................................................................................................................................... 4 4 Conventions ........................................................................................................................................................................................................... 6

4.1 Set Points and Process Values ...................................................................................................................................................................... 6 4.2 Equipment Colors ......................................................................................................................................................................................... 6 4.3 Line sizes and colors .................................................................................................................................................................................... 6 4.4 Instrument Bubbles....................................................................................................................................................................................... 7

5 Control Strategies................................................................................................................................................................................................... 7 5.1 Theory of Operation ..................................................................................................................................................................................... 7 5.2 General Motor Control ................................................................................................................................................................................. 7

5.2.1 Ready to Start ........................................................................................................................................................................................... 8 5.2.2 Motor Failure Alarm ................................................................................................................................................................................ 8 5.2.3 Restart Delay............................................................................................................................................................................................ 8 5.2.4 Sequential Start Delay.............................................................................................................................................................................. 8 5.2.5 Runtime Monitoring................................................................................................................................................................................. 8

5.3 Bioscrubber System Control (M11-201, M11-202) ..................................................................................................................................... 8 5.4 Headworks Exhaust Fans (M11-101, M11-102) .......................................................................................................................................... 8

5.4.1 Alarms and Interlocks .............................................................................................................................................................................. 9 5.5 Exhaust Fan Differential Pressure (PDIT-11-111, PDIT-11-1112).............................................................................................................. 9

5.5.1 Alarms and Interlocks .............................................................................................................................................................................. 9 5.6 Hydrogen Sulfide Monitoring (AIT-11151)................................................................................................................................................. 9

5.6.1 Alarms and Interlocks ............................................................................................................................................................................ 10

May 5, 2006– Rev. 1.0 PLC 24 Odor Control System – SCADA System Operation Manual of 29


5.7 Scrubbant Level Monitoring (LIT-11-211, LIT-11-211) ........................................................................................................................... 10 5.7.1 Alarms and Interlocks ............................................................................................................................................................................ 10

5.8 Packing Differential Pressure (PDIT-11-221, PDIT-11-222)..................................................................................................................... 10 5.8.1 Alarms and Interlocks ............................................................................................................................................................................ 10

5.9 Bioscrubber Recirculation Pump (P11-301, P11-302) ............................................................................................................................... 10 5.9.1 Alarms and Interlocks ............................................................................................................................................................................ 11

5.10 Scrubbant Solution pH (AIT-11-311, FV-11-401, AIT-11-312, FV-11-402) ............................................................................................ 11 5.10.1 Alarms and Interlocks........................................................................................................................................................................ 11

5.11 Headworks Makeup Ventilation Fans (MAU10-911, 912, 921, 922, 931) ................................................................................................ 11 5.11.1 Alarms and Interlocks........................................................................................................................................................................ 12

5.12 Combustible Gas Monitoring (EMP-10-800, EMP-11-800) ...................................................................................................................... 12 5.12.1 Alarms and Interlocks........................................................................................................................................................................ 12

5.13 Odor Control Facility Ventilation Fans (SF-11-911, EF-11-901) .............................................................................................................. 12 5.13.1 Alarms and Interlocks........................................................................................................................................................................ 13

5.14 Temperature Monitoring (TIT-10-941, TIT-11-941, TIT-11-942) ............................................................................................................ 13 5.14.1 Alarms and Interlocks........................................................................................................................................................................ 13

5.15 Nutrient Feed Control and Level Monitoring (LSL-11-501, FV-11-401).................................................................................................. 13 5.15.1 Alarms and Interlocks........................................................................................................................................................................ 13

6 Sample Screens .................................................................................................................................................................................................... 14 6.1 Odor Control Overview.............................................................................................................................................................................. 15 6.2 Bioscrubber #1............................................................................................................................................................................................ 16 6.3 Fan Control Pop-up .................................................................................................................................................................................... 17 6.4 Pump Control Pop-up ................................................................................................................................................................................. 18 6.5 Solenoid Valve Control Pop-up.................................................................................................................................................................. 19 6.6 Dual-Speed Fan Control Pop-up................................................................................................................................................................. 20 6.7 pH Transmitter Pop-up ............................................................................................................................................................................... 21

7 Sample Panel View (OIT) Screens ...................................................................................................................................................................... 22 7.1 Odor Control Overview.............................................................................................................................................................................. 23 7.2 Bioscrubber #1............................................................................................................................................................................................ 24 7.3 Fan Control Pop-up .................................................................................................................................................................................... 25 7.4 Pump Control Pop-up ................................................................................................................................................................................. 26 7.5 Solenoid Valve Control Pop-up.................................................................................................................................................................. 27 7.6 Dual-Speed Fan Control Pop-up................................................................................................................................................................. 28 7.7 pH Transmitter Pop-up ............................................................................................................................................................................... 29



PLC 24 – ODOR CONTROL SYSTEM

SCADA SYSTEM OPERATION MANUAL

Revision 1.0

May 5, 2006 1 Introduction This document presents the operational logic and sample SCADA and OIT (local operator interface terminal) screens for the Odor Control System at the Stockton Regional Wastewater Control Facility.

2 Revision History The table below shows the history of revisions to this document.

Rev. Description By Date1.0 Issued for customer training Max Hanson/

Imran Saeed May 5, 2006

3 PLC System Overview PLC24 controls the operation of the odor control, ferric chloride and the primary polymer systems as shown in the Fig-1 below. A touch-screen Operator Interface Terminal (OIT) is connected to one of the Ethernet channels (CH1) on the main PLC rack, for allowing the plant operator to monitor and control the process locally. Ethernet channel (CH1) is also communicating to RIO24 (remote I/O rack) over the fiber optic cable and the variable speed drives (VFD). This PLC is also communicating to the plant main SCADA system fiber optic Ethernet network, through its second Ethernet channel (CH2).

Process instrumentation of Odor Control System such as pressure, level and flow transmitters and control signals for VFDs and valves are wired to the digital and analog I/O channels of RIO24(remote I/O rack), which are further communicating to PLC. The PLC monitors the process values from the analog and digital input channels of RIO24. When the control mode is in AUTO, the PLC determines the necessary control outputs for achieving the desired process conditions according to the process set points entered by the operator. In Manual mode the plant operator can control the process by manually entering the values through OIT.


Meyer Control Corporation

PLC24 and RIO24 operation is further explained with the help of the blo

OIT (Operator Interface

Terminal)

ETHERNET Sw

Digital I/O Channels

Ethernet Network

Communication. CH1

Analogue I/O Channels

Fiber/Copper Co verter

Ethernet (RJ45)

Fiber optic

FC

FC

RIO 24 – Odor Control System (Allen Bradley Contr l Logix Remote I/O Rack)

Ethernet (RJ45)

Ethernet (RJ45)

Fig-1; PLC-24/RIO-

May 5, 2006– Rev. 1.0 PLC 24 Odor Control System –

Stockton RWCF WW32 / WW39 CH2M Hill / OMI – Thames Water

ck diagram below (Fig-1).

itch

FC

Ethernet (RJ45)

Ethernet Network

Communication.CH1

CPU (Control Logic

Processing)

Ethernet Network

Communication.CH2

Digital I/O Channels

Analogue I/O Channels

PLC24 – Ferric Chloride & Polymer System /Odor Control System (Allen Bradley Control Logix Main PLC Rack)

Ethernet (RJ45)

Fiber/Copper Converter

Fiber optic

n

o

FC Fiber/Copper Converter

Fiber/Copper Converter

Ethernet (RJ45)

Plant Central SCADA

24 Operation Block Diagram

SCADA System Operation Manual of 29


4 Conventions

4.1 Set Points and Process Values Set points appear with a black background inset field and white text. Process values will show an inset field with a white background and blue text. Status indicators also have the white inset field, but the foreground color may change depending upon the conditions and the background will turn yellow for abnormal situations.

Status Indicator Text Colors:

Text Background MeaningDark Red White Not called, inactive, off Dark Green White Called, active, on Gray White Not ready, unavailable for PLC control Black Yellow Alarm, abnormal condition

4.2 Equipment Colors Symbols for motor-driven equipment are animated with colors to reflect status.

Foreground MeaningRed Not called, inactive, off Green Called, active, on Gray Not ready, unavailable for PLC control Yellow Alarm, abnormal condition

Valves symbols are also color-coded.

Foreground MeaningRed Closed Green Opened (or called to open if no feedback) Gray Not ready, unavailable for PLC control Yellow Alarm, abnormal condition

4.3 Line sizes and colors Where appropriate, major process lines are shown with 3D pipe symbols and are animated to show when fluid is flowing. Minor process lines are shown with a dark gray background and an animated foreground color. Minor process lines do not have 3D appearance and are smaller.



Foreground MeaningGray No flow is present

Blue

Plant waterCyan Miscellaneous minor process (e.g., scrubbant)

Yellow Sulfur dioxideLight Green Chlorine or sodium hypochlorite

Magenta Ferric Chloride Pink Polymer

Light Brown Sludge Teal Storm or wastewater

White Air

4.4 Instrument Bubbles Many screens will be arranged to show process flow similar to a Process and Instrumentation Diagram (P&ID). Instrument bubbles will show tag names and will have the relevant process value displayed. These bubbles are animated and will turn yellow when an alarm is present at the instrument represented by the bubble. Clicking on the instrument bubble will open the appropriate pop-up screen (an example for a pH transmitter is shown below).

5 Control Strategies

5.1 Theory of Operation Odor-laden air is drawn from the headworks by the odor control exhaust fans (M11-101, 102) and forced into the base of the bioscrubber towers (M11-201, 202). It then flows up through packing and countercurrent against the scrubbant solution to exit to atmosphere at the top of the vessels. A recirculation pump (P11-301, 302) in each vessel maintains the countercurrent flow of scrubbant fluid. pH of the fluid in the scrubber is monitored and makeup water is added to keep the pH between high and low set points. Air removed from the headworks area is replaced with outside air by five makeup fans.

The odor control PLC also controls ferric chloride and polymer injection. Both of these chemical feed processes use flow pacing to control the dose.

5.2 General Motor Control The following control strategies apply to all motors controlled by the PLC.



5.2.1 Ready to Start A motor is considered ready when it is available for PLC control. For the PLC to start the motor the following conditions must be met: (1) the Off-On-Remote switch must be in the Remote position, (2) the motor must not have an active failure alarm.

5.2.2 Motor Failure Alarm A failure alarm is posted when the PLC calls a motor to run and does not receive running confirmation within an adjustable time delay or when the PLC receives a fault input for the same time delay. Upon a failure, the PLC will de-energize the motor call output and the motor will be considered unavailable. The failure alarm will latch until an operator resets the alarm on the local operator interface or from the SCADA system.

5.2.3 Restart Delay Each motor is equipped with a timer so that the PLC will not call it to run until it has been off for an adjustable time delay. This is intended to allow the motor to rest and allow for any backspin that may be necessary for some pumps or fans. Typically, motor restart delay set points are global to a particular process or PLC.

5.2.4 Sequential Start Delay A sequential start delay is used to prevent simultaneous starting of many motors. This adjustable delay period will be imposed between motor starts.

5.2.5 Runtime Monitoring Elapsed run time is tracked for each motor. This value is recorded in hours (and fractions of hours) and can be reset by the operator.

5.3 Bioscrubber System Control (M11-201, M11-202) Each bioscrubber system is equipped with a master On / Off control. When On is selected, the fans, pumps and valves that are in automatic control mode will operate according to the control strategies below. When the master control is Off, all equipment in automatic mode will stop.

5.4 Headworks Exhaust Fans (M11-101, M11-102) Two modes of operation are available at the Operator Interface Terminal (OIT) or SCADA system.

MANUAL In manual control the fan will start and stop in response to pushbuttons on the operator interface or SCADA screens. Operation will be independent of overall bioscrubber mode.

AUTO In automatic mode, the fan will run whenever the associated bioscrubber is on.



5.4.1 Alarms and Interlocks Two alarms are associated with these fans, a failure alarm and a high differential pressure alarm. A failure alarm will stop the PLC from calling the fan and will also stop two of the Headworks makeup fans. If alarms are disabled for a fan, its output will be held on even if no running confirmation is received. The associated makeup fans will also continue to run.

Operation of the headworks ventilation fans is dependent upon the exhaust fans. The relationship between makeup fans and exhaust fans is shown in the table below.

Headworks Makeup Fan Exhaust Fan #1 M11-101

Exhaust Fan #2 M11-102

Lower Level Fan #1 MAU10-911

Must be running —


— Must be running

Ground Level Fan #1 MAU10-921

Must be running —


— Must be running

Roof Level Fan MAU10-931

Both of the exhaust fans must be running

5.5 Exhaust Fan Differential Pressure (PDIT-11-111, PDIT-11-1112) The differential pressure across the fan is monitored to verify proper fan operation. There are no automatic control functions associated with fan differential pressure.

5.5.1 Alarms and Interlocks The differential pressure will trigger high high and high alarms when over the respective set points. It will also trigger low and low low alarms when below these set points. A common alarm delay is used for all of these alarms. An operator may disable all alarms for this instrument if it is malfunctioning or undergoing maintenance.

5.6 Hydrogen Sulfide Monitoring (AIT-11151) Hydrogen sulfide concentration is monitored at the suction header for the odor control exhaust fans. A single analyzer monitors the feed to both scrubbers.



5.6.1 Alarms and Interlocks The H2S concentration will trigger high high and high alarms when over the respective set points. It will also trigger low and low low alarms when below these set points. A common alarm delay is used for all of these alarms. An operator may disable all alarms for this instrument if it is malfunctioning or undergoing maintenance.

5.7 Scrubbant Level Monitoring (LIT-11-211, LIT-11-211) A level transmitter monitors Scrubbant solution level in the scrubber tower. The recirculation pump will be stopped on a low low level alarm.

5.7.1 Alarms and Interlocks The scrubbant level will trigger high high and high alarms when the level exceeds set points. It will also trigger low and low low alarms when below the respective set points for the alarm delay. The low low level alarm is interlocked with the scrubbant recirculation pump and latches until reset.

5.8 Packing Differential Pressure (PDIT-11-221, PDIT-11-222) The differential pressure across the scrubber packing is monitored so that fouling of the packing can be detected and maintenance actions can be taken. There are no automatic control functions associated with packing differential pressure.

5.8.1 Alarms and Interlocks The differential pressure will trigger high high and high alarms when over the respective set points. It will also trigger low and low low alarms when below these set points. A common alarm delay is used for all of these alarms. An operator may disable all alarms for this instrument if it is malfunctioning or undergoing maintenance.

5.9 Bioscrubber Recirculation Pump (P11-301, P11-302) The recirculation pump moves scrubbant solution from the sump at the base of the scrubber to the distribution header at the top of the packing. Automatic and manual operating modes are available at the OIT and SCADA.

MANUAL In manual control the pump will start and stop in response to pushbuttons on the OIT or SCADA screens. Operation will be independent of overall bioscrubber mode.

AUTO In automatic mode, the pump will run whenever the associated bioscrubber is on.



5.9.1 Alarms and Interlocks The only alarm associated with the recirculation pump is the fail to start alarm. The failure alarm maybe disabled from the OIT or SCADA so that the call output will remain on without running confirmation to allow for troubleshooting.

The recirculation pump is interlocked with the low low level alarm on the scrubber. Once a low low level alarm has been triggered, an alarm reset will be required to restart the recirculation pump.

5.10 Scrubbant Solution pH (AIT-11-311, FV-11-401, AIT-11-312, FV-11-402) A pH analyzer in the recirculation loop monitors the pH of the scrubbant solution. It is controlled by opening and closing a makeup water valve to dilute the scrubbant solution. Excess solution drains to an acid-resistant drain through an overflow. The makeup valve may be operated in auto or manual modes as described below.

MANUAL In manual control the valve will open and close in response to pushbuttons on the OIT or SCADA screens. Operation will be independent of overall bioscrubber mode.

AUTO In automatic mode, the valve will open and close in response to the pH of the scrubbant solution. When the pH exceeds an operator adjustable set point for an operator adjustable time delay, the valve will open. When the pH falls below a second adjustable set point, the valve will close. The valve will only open while the recirculation pump is called to run.

5.10.1 Alarms and Interlocks The pH will trigger high high and high alarms when over the respective set points. It will also trigger low and low low alarms when below these set points. A common alarm delay is used for all of these alarms. An operator may disable all alarms for this instrument if it is malfunctioning or undergoing maintenance.

5.11 Headworks Makeup Ventilation Fans (MAU10-911, 912, 921, 922, 931) Two modes of operation are available at the Operator Interface Terminal (OIT) or SCADA system.

MANUAL In manual control the fan will start and stop in response to pushbuttons on the operator interface or SCADA screens. Operation will be independent of overall bioscrubber mode.

AUTO In automatic mode, the fan will run whenever the associated bioscrubber is on and the required exhaust fan is running (see table below).



5.11.1 Alarms and Interlocks A failure alarm will stop the PLC from calling the fan to run. If alarms are disabled for a fan, its output will be held on even if no running confirmation is received.

Operation of the headworks ventilation fans is dependent upon the exhaust fans. The relationship between makeup fans and exhaust fans is shown in the table below.

Headworks Makeup Fan Exhaust Fan #1 M11-101

Exhaust Fan #2 M11-102


Must be running —


— Must be running


Must be running —


— Must be running

Roof Level Fan MAU10-931

Both of the exhaust fans must be running

5.12 Combustible Gas Monitoring (EMP-10-800, EMP-11-800) Combustible gas concentration is monitored at the headworks and the odor control facility as a safety measure. Should the concentration of combustible gases rise near the lower explosive limit (LEL), alarms will sound so the area can be evacuated. Each of two field mounted environment-monitoring panels receives an input from a volatile hydrocarbon analyzer and controls beacons and audible alarms.

5.12.1 Alarms and Interlocks The environment monitoring panels issue trouble and high combustible gases detection alarms to the PLC. These alarms are posted to the SCADA system, but have no control interlocks.

5.13 Odor Control Facility Ventilation Fans (SF-11-911, EF-11-901) The odor control facility is equipped with a supply fan and an exhaust fan. Two modes of operation are available at the Operator Interface Terminal (OIT) or SCADA system.



MANUAL In manual control the fan will start and stop in response to pushbuttons on the operator interface or SCADA screens. Operation will be independent of overall bioscrubber mode. An operator may choose whether to run at high speed or low speed.

AUTO In automatic mode, the fan will run continuously. If the temperature in the odor control facility exceeds a high set point, the fans will run at high speed until the temperature falls below a low set point whereupon the fans will resume low speed operation.

5.13.1 Alarms and Interlocks A failure alarm will stop the PLC from calling the fan to run. If alarms are disabled for a fan, its output will be held on even if no running confirmation is received.

5.14 Temperature Monitoring (TIT-10-941, TIT-11-941, TIT-11-942) The temperature in the headworks electrical room is monitored for equipment protection, as is that in the odor control facility and the odor control electrical room. The speed of the odor control facility ventilation fans is controlled by its temperature.

5.14.1 Alarms and Interlocks The temperature will trigger high high and high alarms when over the respective set points. It will also trigger low and low low alarms when below these set points. A common alarm delay is used for all of these alarms. An operator may disable all alarms for this instrument if it is malfunctioning or undergoing maintenance.

5.15 Nutrient Feed Control and Level Monitoring (LSL-11-501, FV-11-401) Nutrient is fed to the bioscrubber sump through a solenoid valve.

MANUAL In manual control the valve will open and close in response to pushbuttons on the OIT or SCADA screens. Operation will be independent of overall bioscrubber mode.

AUTO In automatic mode, the valve will open and close in response to scrubber operation and time set points. The valve will open for an adjustable injection period (minutes) on an adjustable interval (hours) of scrubber operation.

5.15.1 Alarms and Interlocks A level switch in the nutrient feed tank (M11-501) will trigger a low level alarm when the tank is nearly empty.



6 Sample SCADA Screens Sample screens for the odor control system follow. These are the screens that will appear on the plant SCADA system. Screens with similar function and design are configured on the local Panelview operator interface and are shown in section 7 of this document.

Please not that no process data was present when these screens were generated. This means that process values will show zero and it is operating scenarios that are not actually possible may be shown.



6.1 Odor Control Overview

This screen presents an overview of the odor control system. It shows operating status of all the major pieces of equipment as well as process values and critical alarms. Clicking on either of the bioscrubber systems will bring up a detailed screen for that system.



6.2 Bioscrubber #1

This screen shows Bioscrubber #1. An identical screen is used for Bioscrubber #2. The status of the nutrient system is added to the information shown on the overview screen, as is detailed status information for the fan, pump and valves. Clicking on one of these pieces of equipment will open pop up screens as detailed below.



6.3 Fan Control Pop-up

This illustrates the pop-up screen for a single-speed fan. With the right security access, an operator can manually start and stop the fan from this screen.

Status indicators change color as well as text to show current status. The start and stop buttons are disabled when in automatic mode.



6.4 Pump Control Pop-up

The pop-up screen for a single-speed pump is illustrated to the left. Its features are very similar to those of the fan screen shown above.

The bell symbol indicates alarms are enabled for this equipment. A “No” symbol appears over the bell to show that alarms are disabled. This is a typical symbol used throughout. Clicking on the bell toggles the status of the alarm disable if the logged-in operator has high enough security access.



6.5 Solenoid Valve Control Pop-up

The solenoid valve screen allows an operator to manually open or close the valve or to select automatic operation.



6.6 Dual-Speed Fan Control Pop-up

Dual speed fans require a slightly different pop-up screen. The called and running indicators will show what speed is being called and which run feedback is being received. In manual mode, the operator selects the desired speed and then starts or stops the fan.

The load shed button allows an operator to select that a piece of equipment will be deactivated when the facility is running on generator power.



6.7 pH Transmitter Pop-up

This pop-up is typical for plant process value transmitters. It allows an operator with security clearance to set alarm set points or disable all alarms associated with an instrument. Status for each alarm is shown adjacent to the set point.



7 Sample Panel View (OIT) Screens Sample screens for local Panel view operator interface for the odor control system follow. The function of these screens is exactly similar to the SCADA screens explained above in section 6.

These are the screens that will appear at the plant Operator Interface Terminal (OIT) of odor control system. Please note that no process data is present in these screens and these were generated during the offline development.



7.1 Odor Control Overview

This screen presents an overview of the odor control system on the local Operator Interface Terminal (OIT). Its function is similar to the SCADA screen explained in section 6.1.



7.2 Bioscrubber #1

This screen shows Bioscrubber #1. An identical screen is used for Bioscrubber #2. Its function is similar to the SCADA screen explained in section 6.2.



7.3 Fan Control Pop-up

This illustrates the pop-up screen for a single-speed fan. With the right security access, an operator can manually start and stop the fan from this screen.

Its function is similar to the SCADA screen explained in section 6.3.



7.4 Pump Control Pop-up

The pop-up screen for a single-speed pump is illustrated to the left. Its features are very similar to those of the fan screen shown above and in section 6.4..

The bell symbol indicates alarms are enabled for this equipment. A “No” symbol appears over the bell to show that alarms are disabled. This is a typical symbol used throughout. Clicking on the bell toggles the status of the alarm disable if the logged-in operator has high enough security access.



7.5 Solenoid Valve Control Pop-up

The solenoid valve screen allows an operator to manually open or close the valve or to select automatic operation.




7.6 Dual-Speed Fan Control Pop-up

Dual speed fans require a slightly different pop-up screen. The called and running indicators will show what speed is being called and which run feedback is being received. In manual mode, the operator selects the desired speed and then starts or stops the fan.




7.7 pH Transmitter Pop-up

This pop-up is typical for plant process value transmitters. It allows an operator with security clearance to set alarm set points or disable all alarms associated with an instrument. Its operation is similar to SCADA screen explained in section 6.7.


odor control system scada system operation manual - stockton odor... · plc 24 – odor control...

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