A P&I drawing shall be provided showing all proposed piping. In general, piping runs shall be as follows:
Off-spec acid from each mix skid (separate lines) to tank R1.
Separate mixed acid line from each skid to tanks T1-T7.
Piping around each tank to provide mixing and a sample tap.
Piping to allow transfer of the contents of any tank to any other tank.
Room sump to R-3 or WWT and cooling tower blow down to WWT.
Piping to transfer R2 and R3 to RI.
Sludge from R1 to lead sulfate recovery.
Other piping as needed to supply acid to the skid, makeup water to R1 and the water tank, R/R for Tank R1 to the mix skid, etc.
If not provided as part of current scope, space shall be provided on the pipe rack to add a second and/or third acid mixing skid. Mixed acid piping from tanks T1 & T2 (combined), T3, T4, and T5 & T6 (combined) shall be run from the distribution pumps on each tank to the wall of the acid mix room. Space on the pipe rack for one additional refill acid shall also be provided. Design of the piping from the wall of the acid mix room to the equipment on the plant floor is not part of the acid mixing system.
5.3 Control Panel
The Acid Mixing System will be monitored and operated from a fully automated UL listed electrical control panel. The main control panel shall be equipped with Programmable Automation Controller (PAC), Allen-Bradley Control Logix (1756 Series) with 100 Mbps Ethernet adaptor and an Allen Bradley Panelview Plus 1000 touch screen Operator Interface. Process and alarm lights and alarm horn shall be included. The process will be automated with operator interface required for system monitoring and control. For each acid mix skid, four (4) variable frequency drives (VFD’s) will be provided in the main control panel for the two (2) rinse reclaim pumps, the one (1) concentrated acid pump, and the one (1) water pump.
Separate Motor Control Center (MCC) with disconnect shall also be provided
5.3.1 System Monitoring and Control
The main control panel shall allow the operator to select the desired system conditions and monitor the operation of the system – flow rates, temperatures, tank levels, etc. This can be done through a series of individual screens, interactive process schematic, or a combination of both. Typical monitoring and operational data required is a follows.
1)All individual screens should have a button allowing the operator to access a Screen Menu that lists all the different screens that are available.
2)Control Screen with the following display/control functions;
Select Auto or Manual Mode
Start/stop and status of all pumps (acid, R/R. water, cooling).
Flow rates – acid, R/R, water, sodium sulfate, and total.
Tank being mixed, and if mixed acid is being directed to R1 or desired tank.
SG setpoint, uncorrected gravity, corrected gravity, acid temperature.
Pump speeds.
Sample timer selection and countdown to next SG determination.
3)Select specific gravity setpoint for each tank.
4)Tank Status
Select On/Off for each tank, if in the off position, acid will not be delivered to the tank regardless of the level.
Tank status; full/not full, low/not low, empty/not empty. Pressing “not low” will allow mixing to top off tank if necessary.
Overide tab to allow mixing even if low level in tank R1. Mixing will stop when “empty” level is reached.
5)Pump speeds settings, concentrated acid, rinse/reclaim, and water for all tanks.
6)Start/stop and status for distribution pumps on each mixed acid tank, as well as R1, R2, and R3.
7)Reclaim tank(s) management.
Sludge pump hand/off/auto.
Select frequency (hours) and duration (minutes) for sludge pump on R1.
Status timers since last cycle and since pump has started.
Auto or manual water makeup to Tank R1.
8)Manual Operation Screen
Buttons to start/stop and set pump speeds for concentrated acid, R/R, and water.
Start/stop/status of cooling water pump.
Setpoint SG, uncorrected SG, acid temp, flow rates, and tank being mixed. These are the same parameters that appear on the “auto” screen.
9)Efficiency Monitor
Total elapsed time (hrs, mins, sec), total run time, percent runtime.
Reset
10)Cooling Tower Screen (See Section 5.3)
Select time between blowdown cycles and length of blowdown.
Timers since last blowdown and time in current blowdown.
Display cooling water temperature.
11)Tank Level
Display volume in each tank – R1, R2, R3, T1-T7.
Allow selection and display of Full (stop fill), Mid (start fill), and Low (pump off) of level setpoint for each tank.
12) Density cell backflush cycle.
Cell backflush hand/off/auto.
Set water pump speed
Frequency and duration of backflush
Elapsed time for frequency and duration.
13) Room sump pump control
Select discharge point, R1 or Wastewater Treatment
Hand/off/auto for pump
14) Active Alarm Screen (flashing light, horn, and/or system shutdown)
Pump faults – include pop-up screen indicating which pump has failed.
No flow conditions; a