As part of the normal plant activity process operators carry out some simple, in process, chemical tests. These are normally designed to ensure that the process stays within prescribed operation limits.
More sophisticated analytical tests are carried out by the Process laboratory staff. These are used to give additional information to the process operators, to ensure that final product is of the correct sales specification , and to provide data for the process records section. In 2003 there were 3 technicians and a laboratory manager.
In addition the laboratory carry out a program of general plant monitoring and monitoring of IPC authorised discharge points. If an on site incident is in progress the staff can be used to monitor the environment and if necessary be sent off site to monitor the surrounding area. A list of the regular tests is shown below.
Most of the above tests are recorded on a check sheet just inside the process laboratory North Door. The SPM should check that the operators have taken the required test and marked the sheet.The sheet also contains information on weekly check samples. These are normally taken on a Tuesday. Again the SPM needs to ensure that these samples have been taken.As well as the in process checks all final products are checked for compliance with the sales specification. Any material which is found to be out of specification results in the process laboratory issuing a Non conformance test note.
This note is issued to the SPM who makes recommendations as to how to correct the situation. This would normally be by changes in plant operation. It is important that for each Non conformance test note that a follow up test is carried out and the result recorded on the original non conformance note.The test note should then be included in the weekly file for checking by the weekend SPM.
The day process laboratory does not provide a full 24 hour cover other than when required for MPBF. It is useful for the SPM to be able to carry out some simple analytical techniques if required. These include titration’s , Bromine moisture tests , gas moisture tests using Shaw meter , vapour detection using HNU or Toxirae detectors , conductivity and pH measurements and a range of Draeger chemical tests.
The company has achieved the BS EN 9002 quality standard. The process laboratory maintain the paper work and carry out analysis that allows us to maintain the registration. Some of these analysis involve the use of statistics and result in the production of Process control charts. The SPM needs to know how to interpret these charts.
The process records department depend on accurate data being recorded by operators and transferred to the Records Clerk on the relevant data sheet. This information is then used to produce information on plant makes and efficiency. It is also used to order raw materials and to schedule the collection of product by customers.The Process Record clerk produces a daily summary sheet of plant production. This is normally e-mailed to the SPM and other members of the process management by mid morning. In addition some of the information is included in the Prod-sum.xls spread sheet in a graphical form.
The SPM should look at this data on a daily basis as it gives the official record of site production and efficiencies etc.
The following information included on the sheet requires daily attention from the SPM.Bromine recovery efficiency and the variance from predicted. Small daily changes are to be expected but sudden changes in trends are important and should be investigated. The reason for any extended negative variance from predicted must be sort.
Sea water flow should be that determined by the set point. Some variation to flow is to be expected due to tidal and climatic factors. A significant reduction in SW flow is normally due to a blockage on the pond gates or static screens. A maintenance schedule needs to be developed for this situation.
Significant changes to PAL strength can effect the efficiency of a number of plants on site. The daily composite figure should be close to the current set point.
High excess SO2 may be due to low extraction efficiencies especially during the colder winter months.
Chlorination-Cumulative should be less than 104 %. Increases in this value suggest that excess chlorine is being used leading to increased costs.
Bromine cumulative conversion would normally be around 97 %. If this value is significantly reduced the operation of the SOT , BLR or bromine packing plants transfers between plant movements should be checked.
Ethylene cumulative loss. This gives an indication of the ethylene loss which is normally less than 2%. Significant increases have been attributed in the past to high ethylene losses at the ethylene gas compressors due to worn seal rings. The operators take a reading of the gas passing the seals once per shift and this record can be consulted to confirm high losses. The second area that ethylene losses have been attributed to is high vent pressures in the reactors.
The DCM and BCM make needs to be checked.
The raw materials stocks needs to be checked as a past record however the stocks prediction on Raw-mats.xls is more useful. This is a spread sheet to predict future stocks levels. The sheet is updated by the record clerk on a daily basis. It is of most use to the SPM as a means of calculating the required Br2 packing rates to fulfil customer’s orders. Once the required packing rate has been set the effect of BOT and SOT shut downs on the predicted PAL stock levels can be calculated.
The Prod-sum.xls. spread sheet is produced by the record clerk as a graphical display of the daily production figures. It contains some addition information which is of use to the SPM.
The loading schedule for the week is on a spread sheet called sales.xls. This is updated a number of times a day by records clerk. The issue number is included in the top right hand corner. At the end of the shift a hard copy should be printed out for the SPM and one for the SOT operator.
From time to time a customer may call up outside normal hours to make a change to the loading schedule. It may also be necessary to make changes due to process requirements. If changes are made it is important if necessary the production rates are adjusted and that the Process records clerk is informed. A monthly production sheet is also produced. This gives information on the production makes and efficiency both for the last month and for the year to date.