Zero Liquid Discharge System (ETP) For Grain Based Distilleries

SSP has designed and supplied DDGS plants to various parties in India as well as abroad. In today's business scenario it is imperative for one to properly address his attention on the economic and environmental aspects that concern the grain-based alcohol producing industries in India vis-à-vis processing of stillage obtained as the by-product after distillation.

SSP is the pioneer in India to have indigenously developed a proven, fully integrated technology for manufacturing Distillers Dried Grains with Solubles (DDGS) from whole grain stillage which is the residue obtained after alcohol has been separated by distillation of the fermented mash of feed stock and water.

SCHEME FOR ZERO LIQUID DISCHARGE SYSTEM ( ETP ) FOR GRAIN BASED DISTILLERIES :

The zero discharge system for grain based distillery effluent handling (DDGS Plant) consists of following main processes.

• Decantation System : To separate the suspended particles and thin liquor.
• Evaporation System : To concentrate the thin liquor in vacuum evaporator.
• Mixing & Blending System : To mix the Wet cake and the concentrate.
• Spin Flash Drying : To dry the mix to get dried powder (DDGS).

THE PROCESS (DDGS) :

The grain stillage from the bottom of analyzer column of grain based distillery is introduced to a continuous decanter centrifuge. Suspended particles are separated as a wet cake from the decanter and thin liquor is further processed to the evaporation section.

The thin liquor from decanter is concentrated in multiple effects falling film vacuum evaporator to get maximum water evaporation per kg steam energy supplied. The total process is under vacuum and the vapours generated in the system are re-used to economize steam consumption. In order to reduce steam consumption in multiple effect evaporation system the thermal vapour recompression system is used. The thermal vapour recompression system use vapours generated in the evaporator and compress it by steam and the compressed vapours are used as heating medium in the evaporator. The concentrate obtained from the evaporator is stored and fed to the mixing section. The wet cake and the concentrate is mixed and blended to for a uniform mix. The so formed mix is fed to the spin flash dryer to dry the wet mix to get dried powder DDGS. Fraction of DDGS at 10% moisture content is re-circulated through the blending section so to reduce the water evaporation load on spin flash dryer.

The DDGS thus obtained is a high protein content product and can be used as catlle feed of good nutritional value.