Glycerol-PMG is obtained as a sump product during the distillation of glycerol. In addition to glycerol, the sump product contains a high-boiling, non-volatile fraction of high-molecular organic components (alkali soaps) and alkali metal salts, which come from the crude glycerol in the upstream production process.

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Typical components of the sump product glycerol-PMG depend on the origin of the raw material and process management:

• organic salts (potassium/sodium soaps)
• inorganic salts (chlorides/sulfates based on potassium/sodium)
• glycerin-based polymers
• Coloring and odor-active components

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The sump product is specifically separated to ensure the quality and purity of the distilled glycerin and is therefore a process-related by-product of glycerol processing.

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Glycerol-PMG is used:

• as a carbon source in the production of biomethane
• as redistillate for glycerol recovery