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Industry:  Petroleum Refinery
Project Type:  DAS (DAHS) Replacement
Scope:  5 Flares, 1 Sulfur Recovery Unit (SRU)
Driver:  NSPS Subpart Ja Deadline
Regulation(s):  40CFR60 - Subpart Ja, Texas State Permit
Parameter(s):  Total Sulfur, H2S
Location:  Texas
Year:  2017

Project Description

This refinery is a high capacity, complex facility with over 100 CEMS on its 39 sources. They have been using ESC|StackVision on the majority of their CEMS since 2002. During this project five flares and a Sulfur Recovery Unit (SRU) were switched from a different data acquisition system (DAS) to using StackVision in time for the initial NSPS Subpart Ja deadline. Below are some of the problems faced with the old DAS, driving the need to seek the solutions StackVision provided.

Problems or Requirements

Increased Monitoring on Each Source
Complying with Subpart Ja increased the need to monitor and report from multiple analyzers on a single source.
Conflicting Rules on Same Analyzer
TCEQ and NSPS regulations applying to the flares are quite different from each other. This means that there is a need to calculate groups of multiple compliance averages and limits, each having different rules for calculation, alarming, reporting and recordkeeping on the same analyzer.
Delay in Data Availability
The DAS being replaced had a two-hour delay in providing the data. This was unworkable for Ja, EPCRA, and generally unacceptable during upsets.
A “Black Box”
Like many simple data acquisition systems, their old DAS was like a black box recorder on an airplane. There was no ability to see how the calculations were being rolled up, show them to an auditor or adjust them without assistance from the provider.
Limited Reports
Reports generated were the minimum necessary for compliance and could not be configured by personnel at the facility.

Solutions and Outcomes

Complexity Handled
We have long experience dealing with conflicting state and federal requirements. So, we were able to sensibly configure their systems to handle the multiple monitors per source and multiple rules per monitor.
Data Immediately Available
Dashboards, Modbus, hardware connections and a range of notification options make the data readily available to operators, environmental and other plant personnel.
StackVision allows users to examine, summarize and edit data down to the minute level (10 seconds for Opacity). They can now drill down into the underlying calculations and parameters for any data point.
Complete configuration tools for our DAS are accessible to users with the correct permission level assigned.
Usable Reports
The environmental engineer takes advantage of easily scheduled reports. He has Calibration (Validation), Downtime, Exceedance, 30-Day Rolling Average and other reports sent to him daily and also semi-annual, annual and 365 day rolling average reports.

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