Method and system for increasing the yield and/or purity of protein and oil from a grain protein and grain oil recovery system

A method for increasing protein yield and/or purity from a whole stillage byproduct produced in a biofuel and/or biochemical production process comprising:

• separating a whole stillage byproduct into a fiber portion and a liquid slurry, which includes initial free oil and protein particles;
• adding at least a portion of a retentate, which includes residual protein particles and residual free oil, that is received from a later step in the method to the liquid slurry, and separating the liquid slurry, via weights, into a protein portion, including combined initial and residual protein particles, and a water soluble solids portion, including combined initial and residual free oil, wherein the addition of the retentate increases the overall concentration of protein particles and free oil in the liquid slurry and facilitates separation of a larger concentration of protein particles in the protein portion;
• thereafter, separately adding a wash water to the separated protein portion followed by dewatering the protein portion to provide a liquid fraction and a protein wet cake fraction, including the combined protein particles;
• and
• cooling the liquid fraction, via a heat exchanger, followed by filtering the cooled liquid fraction, via a membrane, to provide a retentate, including residual protein particles and residual free oil, and a permeate, wherein at least a portion of the retentate defines the portion of the retentate received from the later step in the method, and
• wherein the protein wet cake fraction defines a high protein meal that includes from 48 wt % to 70 wt % protein on a dry basis.

A system for increasing protein yield and/or purity from a whole stillage byproduct produced in a biofuel and/or biochemical production process comprising:

• a first apparatus that receives a whole stillage byproduct produced in a biofuel and/or biochemical production process, wherein the first apparatus separates the whole stillage byproduct into a fiber portion and a liquid slurry, which includes initial free oil and protein particles;
• a second apparatus that is situated after the first apparatus, the second apparatus receives the liquid slurry from the first apparatus and whereat at least a portion of a retentate, which includes residual protein particles and residual free oil, is added to the liquid slurry from a later apparatus in the system, the second apparatus configured to separate the liquid slurry into a protein portion, including combined initial and residual protein particles, and a water soluble solids portion, including combined initial and residual free oil, wherein the addition of the retentate increases the overall concentration of protein particles and free oil in the liquid slurry and facilitates separation of a larger concentration of protein particles in the protein portion;
• and
• a third apparatus that is situated after the second apparatus and that receives the protein portion from the second apparatus and whereat wash water is added to the protein portion, the third apparatus configured to dewater the protein portion to provide a liquid fraction and a protein wet cake fraction, including the combined protein particles;
• and
• a filtration device that is situated after the third apparatus and that receives the liquid fraction, the filter device configured to separate the liquid fraction into a retentate, including residual protein particles and residual free oil, and a permeate, wherein at least a portion of the retentate defines the portion of the retentate received at the second apparatus from the later apparatus in the system, and
• wherein the protein wet cake fraction defines a high protein meal that includes at least 48 wt % protein on a dry basis.