FIELD OF THE INVENTION

The present inventions relate to the field of ethanol production. The present inventions more specifically relate to the field of balancing water entering and leaving an ethanol plant, and/or improving plant thermal efficiency.

BACKGROUND

Nearly all ethanol plants struggle to maintain a proper balance of water entering and leaving their facilities while minimizing the energy required for evaporation and for drying when dryers are present. Some plants are able to discharge water to a city or other wastewater plant to help with the balance, and other plants allow the water to be eliminated either through what is called wet cake (wet distillers grains) or through dryers when the facility produces dry distillers grains (DDG). The wet distillers grains may have what is called “syrup” applied up stream of a dryer, in which case the dried grains are called dried distillers grains with solubles (DDGS). While the DDGS provide certain material benefits, water elimination from the syrup also occurs.

Thin stillage results when whole stillage from distillation is processed in decanters designed to separate suspended solids and water. Not all solids are removed, and the water that contains these solids, dissolved and suspended, is called thin stillage. The syrup applied to the wet grains results when some of the water in the thin stillage is evaporated. Ethanol plants typically use some form of falling film evaporation to remove this water. The more water that is removed from the thin stillage, the thicker and more viscous the syrup but less energy is required when dryers are used. Because the water being evaporated typically becomes process condensate, the plant water balance is also impacted.

Water removal and thus, syrup concentration is limited in the typical falling film evaporator due to increasing viscosity. While a high efficiency forced circulation evaporation system can allow a significantly greater syrup concentration to be obtained, these systems are expensive, can be costly to operate, and water balance is still impacted and must be addressed in one form or another.

Water balance can become even more of an issue when a facility expands its ethanol production. While existing evaporation systems may be modified to accommodate increased evaporation needs resulting from process expansion at a facility, the increased evaporation also leads to increased load on existing evaporation equipment and excess water that needs to be addressed to maintain an acceptable facility water balance. While traditional evaporation methods and equipment can be used to help address the water balance challenge, such an approach also requires a significant energy cost for system operation.

Accordingly, there is a need for an improved ethanol plant evaporation process that increase plant efficiency and/or reduces the Carbon Intensity (CI).

Accordingly, there is a need for an improved ethanol evaporation process that provides a more optimal water balance utilizing existing environmental controls. There is also a need for an improved ethanol process that allows for shorter delivery and construction times relative to typical evaporation equipment (i.e., falling film evaporators or other traditional evaporators that utilize heat exchangers with tubes, plates or other physical barrier between types of fluids). In particular, a preferred improved ethanol process requires less or minimal heat transfer surface, mass transfer packing, and/or heat transfer media, thereby reducing or minimizing component parts that are known to foul and plug, and may require less regular maintenance and cleaning, and thus, reduce the typical expense associated therewith.

There is also a need for an improved ethanol process that costs less to construct, install, operate and/or maintain relative to other known ethanol plants of similar capacity and/or process size. Additionally, there is a need for an improved ethanol process that, depending on the existing ethanol plant or process design, can be retrofit into the existing facility to reduce condensing load on existing evaporators, reduce the energy used to operate existing evaporators, and/or reduce bottlenecks in the existing evaporators to generally improve the overall plant energy balance and efficiency and/or Carbon Intensity. Thus, there is a need for an improved ethanol process and plant design that can improve water balance by utilizing what is typically considered excess or waste heat in a typical plant or process. There is also a need for an improved ethanol process and plant design that helps improve water balance while also improving the typical production process (e.g., by cooling and/or concentrating process fluids before or after a typical evaporation step or process is provided or applied, such as in a falling film evaporator).

SUMMARY

Improved ethanol plant designs, processes, and methods with improved evaporation and/or more optimal water balance are provided. In particular, the provided improved ethanol plant designs, processes and methods are relatively simple, cost effective and allow for shorter delivery and construction times relative to typical evaporation equipment (i.e., falling film evaporators or other evaporators which utilize heat exchangers with tubes, plates or other physical barrier between types of fluids).

Additionally, improved ethanol plant designs, processes and methods are provided that reduce or minimize the need for tubes, mass transfer packing, and/or heat transfer media, thereby reducing component parts that are known to foul and plug. Such an improved ethanol plant requires less regular maintenance and cleaning and thus, decreases the typical expense associated therewith. The provided improved ethanol plant designs, processes and methods may be retrofit into the existing plant or process (depending on the existing ethanol plant or process design) to reduce condensing load on existing or new evaporators, reduce the energy used to operate existing or new evaporators and/or reduce bottlenecks in the existing or new evaporators, are also provided. Accordingly, the provided improved ethanol plant designs, processes and methods cost relatively less to construct, install, operate and/or maintain relative to other known ethanol plants of similar capacity and/or process size.

The provided improved ethanol plant designs, processes and methods can improve water balance by utilizing what is typically considered excess or waste heat in a typical plant or process. Accordingly, the improved ethanol processes, plant designs and methods help improve water balance while also improving the typical production process (e.g., by cooling and/or concentrating thin stillage before the typical evaporation step or process is provided or applied, such as in a falling film evaporator).

The present disclosure relates to the application of an open column or other direct contact evaporator (DCE) at ethanol facilities to remove water from mash, whole stillage, thin stillage, syrup, and/or process condensate to improve fluid concentration and/or energy efficiency, while balancing water entering and leaving an ethanol plant.

In one aspect, the present disclosure provides for a method for ethanol production, the method comprising: providing thin stillage formed during ethanol production into an open column or other direct contact evaporator to help balance the water content of the thin stillage to form a concentrated thin stillage.

In another aspect, the present disclosure further provides for a method for ethanol production, the method comprising: providing process condensate formed during ethanol production into an open column or other direct contact evaporator to form a further condensed process condensate.

In another aspect, the present disclosure further provides for a method for balancing water content in a mixture, the method comprising: providing a mixture in an open column direct contact evaporator; and providing air in the open column or other direct contact evaporator to reduce the water content of the mixture through direct contact evaporation.

