Atch_9_-_Partial_Design_Analysis.pdf

CH&PP REPAIR ASH HANDLING CONTROL SYSTEM

EIELSON AFB, ALASKA

PROJECT NO.: FTQW 12‐1008

DESIGN ANALYSIS

FINAL CONSTRUCTION DOCUMENTS

Design Alaska, Inc. Page 1 of 19

REFERENCE STANDARDS

The following reference standards were used in the development of this project:

NFPA 85 – Boiler and Combustion Systems Hazards Code 2015

NFPA 70 – National Electrical Code 2017

CURRENT SYSTEM

Bottom Ash Control System

The existing bottom ash collection control system was installed in 1987 and is based on an Allen‐Bradley PLC 5 and a PanelView 1200 HMI. Both the PLC and HMI are no longer supported by the manufacturer and cannot be replaced with similar hardware. In addition, the existing panel is an upgrade from an older system. Many of the indicator lights and switches on the existing control panel are no longer functional.

Below are pictures of the three existing panels.

Figure 1 – Existing Panels

The leftmost panel shown below contains indicator lights on an old stenciled graphic that is no longer used.

PROJECT NO.: FTQW 12‐1008

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Figure 2 – Existing Panels

The center panel has the Panelview HMI mounted on the front and contains two remote I/O racks inside as shown in the following pictures. The Panelview 1200 is no longer supported by Allen Bradley and cannot be replaced without upgrading.

Figure 3 – PanelView 1200

PROJECT NO.: FTQW 12‐1008

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Figure 4 – Remote I/O Racks

The panel on the right has many control switches, a static graphic of the system and a Yokagowa chart recorder mounted on the front. Inside this panel is the PLC in an I/O rack for the remaining points for the bottom ash as shown in the following pictures.

Figure 5 – Switch Panel

PROJECT NO.: FTQW 12‐1008

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Figure 6 – PLC5 and Racks 1 & 2

Currently the PLC and I/O modules are no longer supported by Allen Bradley and cannot be replaced without upgrading. The plan is that the three panels that currently exist for the bottom ash control system will be removed after the new system is in place and commissioned.

Fly Ash Control System

The existing fly ash collection control system was installed around 2005 and is based on an Allen‐Bradley SLC‐5/03 and a Nematron HMI running RSView 32. Both the PLC and HMI are outdated and cannot be replaced with similar hardware. Below is a picture of the front of the existing panel.

PROJECT NO.: FTQW 12‐1008

DESIGN ANALYSIS

FINAL CONSTRUCTION DOCUMENTS

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Figure 7 – Fly Ash Control System

The following is a picture of the inside of the existing fly ash panel showing the PLC with a serial cable going to the HMI. In addition to the main rack, there is an expansion rack for additional I/O modules.

Figure 8 – Existing Fly Ash Panel Inside

PROJECT NO.: FTQW 12‐1008

DESIGN ANALYSIS

FINAL CONSTRUCTION DOCUMENTS

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The upgrade plan is that the panel that currently exists for the fly ash control system will be removed after the new system is in place and commissioned.

Ash Unloading Control System

The existing ash unloading systems consist of separate controllers and operating pushbutton stations for each respective silo. The ash unloading system moves ash from the silos to the trucks below for transportation to the local landfill.

The south silo system is for bottom ash unloading and is run with a combination of a hardwired operator pushbutton panel and a PLC panel that has an Allen Bradley Micrologic 1500 for control. The following pictures show the operator pushbutton panel and the PLC panel.

Figure 9 – South Operator Pushbutton Panel Front

PROJECT NO.: FTQW 12‐1008

DESIGN ANALYSIS

FINAL CONSTRUCTION DOCUMENTS

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Figure 10 – South Operator Pushbutton Panel Inside

The upgrade plan is to replace both panels with new panels in the same locations.

Figure 11 – South PLC Panel Front

PROJECT NO.: FTQW 12‐1008

DESIGN ANALYSIS

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Figure 12 – South PLC Panel Inside

The north silo system is for fly ash unloading and is run with a combination of hardwired and PLC control that is Allen Bradley Micrologic 1200. The following pictures show the operator pushbutton panels and the PLC panel.

Figure 13 – North Operating & PLC Control Panels

PROJECT NO.: FTQW 12‐1008

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Figure 14 – North PLC Panel Front

Figure 15 – North PLC Panel Inside

PROJECT NO.: FTQW 12‐1008

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Figure 16 – North Operator Panel Front

Figure 17 – North Operator Panel Inside

The upgrade plan is that the panels that currently exist for the fly ash & bottom ash unloading systems will be replaced after the new system is in place and commissioned.

PROJECT NO.: FTQW 12‐1008

DESIGN ANALYSIS

FINAL CONSTRUCTION DOCUMENTS

Design Alaska, Inc. Page 11 of 19

Ash Unloading Feeder VFDs

The ash unloading systems use a screw feeder under the silos to move ash from the silo to the truck inlet.

For the North silo, there is a single feeder and for the South silo, there are two. All three of the VFD panels will need to be replaced. Below are pictures of a typical VFD panel.

Figure 18 – VFD Panel Front

Figure 19 – VFD Panel Inside

PROJECT NO.: FTQW 12‐1008

DESIGN ANALYSIS

FINAL CONSTRUCTION DOCUMENTS

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Ash Silo Level Instruments

Both ash silos currently do not have reliable level indication. Operators use a manual weighted chain to determine level in the South ash silo as shown below.

Figure 20 – Bottom Ash Silo Manual Level Detection

For the fly ash silo there is a microwave level sensor shown in the picture below. That sensor is mounted near the side of the silo so it cannot detect level in the bottom cone section of the silo. The way the silo is currently operated is that it is not filled much beyond the lower cone section; therefore, the level sensor never shows any level.

PROJECT NO.: FTQW 12‐1008

DESIGN ANALYSIS

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Figure 21 – Fly Ash Silo Level Transmitter

Truck Unloading Level Instruments

The current truck level sensing instrument does not work and will not sense when the truck is full to indicate to the operator to close the ash discharge. This is the situation for both the North and South truck unloading stations. Below is a picture of the existing truck loading spout.

Figure 22 – Truck Unload Level Instrument

PROJECT NO.: FTQW 12‐1008

DESIGN ANALYSIS

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Pulse Jet Bag Filter Panels

The pulse jet filter panels have mechanical drum sequencer switches that control the filter sock cleaning process. These components are no longer available and need to be replaced with a system that will provide the same functionality and provide the ability to get replacement parts. Below are pictures of those panels. There are 2 total panels to be replaced.

Figure 23 – Pulse Jet Filter Panel

Figure 24 – Pulse Jet Filter Panel Inside

PROJECT NO.: FTQW 12‐1008

DESIGN ANALYSIS

FINAL CONSTRUCTION DOCUMENTS

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ASH SYSTEM UPGRADE – SCOPE OF WORK

Bottom Ash Control System

The bottom ash PLC 5 control system will be completely replaced by a new redundant PLC system that will host all of the existing bottom ash I/O in a new enclosure. This new enclosure will also have a new HMI mounted in the front that will have all the graphics that the existing bottom ash system has as well as all the fly ash system graphics, as the systems will be combined to the single redundant PLC. The existing bottom ash enclosure will be used as a marshalling panel. This enclosure will also have all the required hardware to provide a fully functional PLC /HMI system such as network switches, power supplies, fused terminal blocks, fans transformers, lights, outlet and interconnecting cables. The contractor will be responsible for programming the PLC system to function as it currently does and configure the HMI to provide all the graphic screens that currently exist on the current system. One of the existing cabinets will hold an HMI for screen redundancy.

Fly Ash Control System

The fly ash SLC 5/03 control system will be completely replaced by the same redundant PLC enclosure and remain as a marshalling cabinet. The existing enclosure will interface to the new ash PLC. This HMI will have all the graphics that the existing fly ash system has as well as all the bottom ash system graphics as the systems will be combined to a single redundant PLC. Since the graphics for either system are available on both HMI’s, they will serve as redundancy on the HMI level.

Ash Unloading Control Systems

The existing bottom ash unloading control system for the south silo will be completely replaced with a new operator panel, PLC panel and VFD panels. The new operator panel will be located where the existing panel resides since the location allows the operator to observe the truck filling. The new operator panel will have pushbuttons that are like the existing pushbutton panel with the addition of the three indicator lights and E‐Stop pushbutton currently on the PLC panel. This will keep the operator from having to go to the PLC panel, which is on a level higher, to see alarms and E‐Stop the unloading. The new PLC panel will replace the existing panel at the same location as the existing Micrologix 1500. The new VFD panels will replace the existing panels at the same location to minimize the impact of pulling new wires.

The existing fly ash unloading control system for the north silo will be completely replaced with new operator panels, PLC panel and VFD panel. The new operator panels will be located where the existing panels reside since the location allows the operator to observe the truck filling. The new operator panel will have pushbuttons that are like the existing pushbutton panel. The new PLC panel will have the same indicators and switches that exist on the current panel and will be located where the existing panel is. The new PLC panel will replace the existing panel and have the same program logic as the current Micrologix

PROJECT NO.: FTQW 12‐1008

DESIGN ANALYSIS

FINAL CONSTRUCTION DOCUMENTS

Design Alaska, Inc. Page 16 of 19

1200. The new VFD panel will replace the existing panel at the same location to minimize the impact of pulling new wires.

Ash Unloading Instrumentation

Both bottom ash and fly ash silos need new level instruments that can read the level of ash down into the cone section. The new level sensors need to be radar type with adjustable heads such that they can be focused towards the cone section to read level in that area. Both silos have existing penetrations for the instruments and the North silo has an existing flange for mounting. The South silo will need to include a flange for mounting the sensor and wiring to the existing PLC since there is no existing wiring like the North silo.

The truck unloading sensors will also need to be replaced. The new level sensors need to be a pneumatic type sensor that has a poly tube that travels with the spout. When the tube is plugged by the rising level of ash in the truck, it creates a backpressure that activates a switch to indicate high level.

Bottom Ash Bin Vent Pulse Jet Bag Filter Panels

The pulse jet filter panels must be replaced with new panels that will provide the same air pulse cleaning control as the existing system. There are two total panels that are to be replaced. It is the intent of this project to keep the existing field instruments, compressed air, power, wiring, and integrate the new panel to these items. The new panels shall be located where the existing panels are to minimize any installation effort.

HAZARDOUS MATERIAL INVESTIGATION

ACM is present in the building. Project concerns include a layer of asbestos containing material (ACM) insulation in between the wall paneling of the exterior walls. Thermal system insulation is present intermittently throughout the facility, the project should avoid disturbing this insulation. Ash Handler control panels and associated wiring was confirmed to be non‐ACM.

Settled dust on horizontal surfaces contains silica and RCRA‐8 metals contamination and will impact project work activities. Equipment scheduled for replacement should be precleaned by qualified workers, working under a project specific work plan to minimize exposure to silica and metal inhalation.

Lead‐Based paint was not identified; the control panels can be demolished as non‐lead based paint containing. Universal wastes were not identified within the project scope of work.