Reference methods: releases of vinyl chloride from plants, chapter 3


Part 1: Sampling

Method S-3: Sampling of polyvinyl chloride resins and resin slurries in polyvinyl chloride plants

S-3.1 Scope

Procedures are described for obtaining PVC resin or resin slurry samples for the determination of releases of VC into the atmosphere after the stripping operation in the manufacture of PVC.

S-3.2 Apparatus

S-3.2.1 Bottles

Polypropylene or glass bottles of at least 60 mL capacity with screw caps are required for the resin or resin slurry samples.

S-3.3 Procedures

S-3.3.1 Location of Sampling Point

The PVC resin or resin slurry samples shall be obtained immediately downstream of the stripping operation, either at a point in the transfer line from the stripper to storage or subsequent operation or directly from the stripper before transfer to subsequent operations.

S-3.3.2 Collection of the Sample

Allow the resin or slurry in the sampling line to flow so as to purge the line of any old material. When the line has been purged, place a sampling bottle or a sampling container under the tap, and fill to capacity. Immediately cap the sampling bottle, or, if a sampling container was used for sample collection, immediately transfer the sample to a sampling bottle, then cap immediately.

If sampling the PVC resin from a batch stripping process, take a first sample within five minutes of the beginning of the product transfer operation from the stripper to storage, and an additional sample at each subsequent five-minute interval until the transfer of the resin from the stripper to storage is completed. Label each of the bottles with an identifying number or code and record this information on Form S-3.1.

If sampling the resin from a continuous stripping process, purge the sampling line prior to taking each sample. Take three samples at five-minute intervals. Label each of the three bottles with an identifying number or code and record this information on Form S-3.1.

S-3.4 Sample Analysis

The residual VC in the resin shall be analyzed using Method A-2 contained in Part 2 of this Reference Method.

S-3.5 Calculations

Sample test data may be recorded in the units for which the sampling equipment is designed. However, if those units are different than those set out in this sampling method, they shall be converted to the units used in the equations of this sampling method.

The VC releases downstream from stripping operations may be determined by measuring the residual vinyl chloride monomer (VCM) in the PVC product or resin slurries, by measuring VC in process vents or stacks downstream from the stripper, or both.

S-3.5.1 Equations

(See S-3.5.2 for nomenclature)

Releases Based on Resin Samples Only

The release rate of VCis calculated assuming total evolution of the residual VC in the resin or resin slurry during all operations subsequent to stripping. Equation S-3.1, shown below, is to be used to calculate the mass release rate:

Equation S-3.1

Releases Based on Process Vent or Stack Gas Only

The release rate of VCdownstream from the stripping operation is determined by measuring the releases from every process vent or stack of all operations following the stripper.

The mass releases of VC expressed on the basis of 100 kg of PVC produced (ERvc/pvc) are calculated for each process vent or stack according to the calculations provided in Method S-1.

The total mass release of VC is the sum of the mass releases from all process vents or stacks following the stripper as calculated by equation   S-3.2:

Equation S-3.2

Releases Based on Both Resin Samples and Process Vent or Stack Gas Samples

The release rate of VCdownstream from the stripping operations is determined by measuring the residual VC in the product resin after any processing following the stripper and concurrently measuring the releases into the atmosphere from all process vents or stacks of all operations between the resin sampling point and the stripper.

The mass releases of VC expressed on the basis of 100 kg of PVC produced by each process vent or stack sampled (ERvc/pvc) are calculated according to the calculations provided in Method S-1.

The releases from all operations following the resin sampling point are calculated using equation S-3.1. If two or more resin streams are sampled, the mass release rate (ERvc/pvc) as calculated for each stream shall be weighted in proportion to the quantity of PVC produced as obtained from the plant production records.

The total of the releases of VC downstream from the stripper is obtained by totalling the releases (ERvc/pvc) from each process vent or stack sampled and adding to this quantity the sum of the weighted release rates calculated from the residual VC of the product resin streams as described by equation S-3.3:

Equation S-3.3

S-3.5.2 Nomenclature

m
number of vents sampled downstream of the stripper

n
number of product resin streams sampled

C rvc
average residual VCin the resin or resin slurry samples on a dry basis, ppm VC by weight (as determined by equation A-2.3 of A-2.4.9 within Part 2 of this Reference Method)

(ER vc/pvc) i
mass release rate of VC from vent number i(calculated with equation S-1.4), kg VC per 100 kg of PVC

(ER vc/pvc) j
mass release rate of VC from product resin stream number j (calculated with equation S-3.1), kg of VC per 100 kg of PVC

(ER vc/pvc) total
total releases of VCdownstream from the stripper, kg of VC per 100 kg of PVC

(P pvc) j
production rate of PVC resin from product stream number j, 100 kg of PVC per day

10 -4
conversion factor, ppmto kg of VC per 100 kg of PVC

Form S-3.1: Resin and resin slurry samples

Plant:

____________________________

Date:

____________________________

Sampling Location:

____________________________

Samples Taken by:

____________________________

First Sample Number:

____________________________

Local Time:

____________________________

Second Sample Number:

____________________________

Local Time:

____________________________

Third Sample Number:

____________________________

Local Time:

____________________________

Resin Type / Batch Number:

____________________________

Plant name and street address of site where sample was collected:

____________________________



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