SUEZ Water - Water Technologies & Water

Dry Milling Ethanol Treatment Solutions

In the dry milling corn-to-ethanol process, operators are continually seeking ways to improve process efficiency and lower operating costs to help drive the overall profitability of the plant and increase competitiveness.

SUEZ offers a comprehensive portfolio of treatments, equipment and analytics solutions to help ethanol producers increase yield, manage downtime and reduce total cost of operation.

Process Overview

Dry milling ethanol process overview

Cooking

When corn flour is mixed with water and enzymes, beerstone (calcium oxalate) can form within the slurry tanks, heat exchangers and piping, which requires cleaning and leads to downtime and lost productivity. This issue can be more pronounced where water recycling efforts introduce high calcium recovery streams to the slurry tanks. Our FoodPro* OLC products can minimize scaling, reduce acid and caustic use, and increase productivity in the cooking processes.

Fermentation

This process converts the starch into ethanol. Beerstone can also form here, both in the fermentation coolers and fermentation tanks, since calcium oxalate has a low solubility at the standard operating temperatures (90-100oF). If scale forms in the heat exchangers, temperature control can become inefficient and affect productivity. Our FoodPro* DCF products can minimize scaling, reduce acid and caustic use, and increase the productivity of the fermentation stage.

Clean-in-Place (CIP) Enhancement

Ethanol beer/mash heat exchangers, fermentation coolers and tanks are typically sanitized every 24 to 48 hours, or after every batch, to remove organic fouling, which may lead to bacterial hide-out and reduction in efficiency and lost production. Our FoodPro* OLC is added to the CIP solution to improve offline cleaning of organic and inorganic contaminants, reduce acid and caustic use, improve ethanol conversions and increase production.

Distillation

Ethanol is removed from the beer at this stage, often done using a three-column approach (beer, rectifier and stripper columns). Fouling can occur as the high-solids containing stream cascade down multiple trays in the beer column. Fouling can also be observed if a reboiler is used to increase distillation temperatures. Doing a CIP on a column or reboiler typically requires plant shutdown, resulting in lost production. Our FoodPro* DCF can reduce fouling and extend the run-length of the distillation systems, reducing plant downtime.

Evaporation

The solids stream from the beer column bottoms, or “whole stillage,” separated through centrifuges with the remaining centrate stream directed towards the backset and “thin stillage.” The thin stillage stream is sent to multi-effect evaporators to concentrate the remaining solids into syrup. Evaporator fouling occurs throughout the evap system, with heavier fouling in the vessels where the liquor concentration is highest. Inorganic and organic deposition can be controlled with our FoodPro DCF products. CIP cleanings, when required, can also be enhanced with our FoodPro OLC products.

The key to optimizing energy use and productivity is to execute CIP actions strategically only to the evaporators that require it, when they require it. Our iVAP analytics can monitor each evaporator vessel’s operation to determine which vessel requires cleaning and when.

Storage

Ethanol in storage tends to absorb water, which can lead to corrosion of motors and equipment that transports it throughout the blended motor fuel supply chain. Our ethanol corrosion inhibitors can prevent corrosion, and the tracer it contains makes for easy testing of its presence and concentration.

 

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Key products & services

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