BS ISO 17786:2015 pdf download

BS ISO 17786:2015 pdf download.Dimethyl ether (DME) for fuels — Determination of high temperature (105°C) evaporation residues — Mass analysis method
1 Scope
This International Standard specifies a procedure of test for high temperature (105 °C) evaporation residue in DME used as fuel by the mass analysis method. This procedure is applicable to determine the amount of high temperature (105 °C) evaporation residue up to the value specified in ISO 16861. Several tests can be applied to determine amount of evaporation residue in liquefied products. Among them, this International Standard specifies the method that has detection limit sufficient for a DME specification in ISO 16861, using less resource compared to other methods. When more precise quantitative test is required, use of ISO 13757 instead of this International Standard is recommended. Because of the procedure applied, the evaporation residue which has a boiling point lower than 105 °C will not be determined. NOTE The precision of this method has been studied for a limited set of samples and content levels by a limited amount of labs. It allows establishment of a quality specification of DME but cannot be considered as a full precision determination in line with the usual statistical methodology as in ISO 4259.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 16861, Petroleum products — Fuels (class F) — Specifications of Dimethylether (DME)
ISO 29945, Refrigerated non-petroleum-based liquefied gaseous fuels — Dimethylether (DME) — Method of manual sampling onshore terminals
3 Principle
After approximately 100 g of liquid sample is evaporated by using an evaporation dish, the residue is weighed, to determine the evaporation residue at 105 °C in mass percentage of the total DME.
4 Reagents and materials
4.1 Ethanol, methanol and/or isopropanol is used for cooling bath.
4.2 Dry ice, used for cooling bath.
6 Procedures
6.1 Samples shall be taken as described in ISO 29945.
6.2 The clean evaporation dish is placed into the oven at 105 °C for 60 min, and cooled in the desiccator for another 30 min. The mass is measured to the digit of 0,1 mg. [A, mass of the evaporating dish (g)].
6.3 Dry ice and methanol are put into the cooling bath (to be under – 50 °C), to cool the spiral tube.
6.4 Sample cylinder, connecting pipe, cooler are connected as shown in Figure 1. Then, the valves are opened in the order of the sample cylinder valve, sample valve and needle valve, and the connecting pipe,spiral tube are prewashed with the liquid sample.
6.5 The sample cylinder valve is opened, and the sample is led into the evaporation dish in liquid state.At this time, the sample is supplied gradually until the evaporation dish cools down. Needle valves should be used to adjust the sample flow.