Kraft Mill Biorefinery to Produce Acetic Acid and Ethanol: Technical Economic Analysis

UMaine Alert

Posted: April 19, 2024 - 1:32 PM

At approximately 9:24 a.m. on Friday, April 19, a University of Maine graduate student was struck by a university vehicle on Long Road at the University of Maine campus in Orono. The student reports that they are at a local hospital with minor injuries.

Emergency services, including the Orono Fire Department, University Volunteer Ambulance Corps, University of Maine Police Department, Orono Police Department and Penobscot County Sheriff’s Office responded to the scene.

The university vehicle involved in the incident was a Chevrolet Express van. It was being operated by a university employee.

Counseling services and support are available for students, faculty or staff who may have been affected. The Counseling Center can be reached at 207-581-1392 and the Dean of Students Office can be reached at 207-581-1406.

The scene has been cleared and Long Road is now accessible. An investigation is being conducted by the University of Maine Police Department with assistance from the Penobscot County Sheriff’s Office Crash Reconstruction Unit. Any witnesses to the incident are encouraged to contact Lt. Noel Santiago at noel.santiago@maine.edu.

Published: 2010

Author(s):

Adriaan van Heiningen
Haibo Mao
Hemant Pendse
Joe Genco

Abstract:

The “near neutral hemicellulose extraction process” involves extraction of hemicellulose using green liquor prior to kraft pulping. Ancillary unit operations include hydrolysis of the extracted lignin, liquid-liquid extraction of acetic acid, liming followed by separation of gypsum, fermentation of C5 and C6 sugars, and upgrading the acetic acid and ethanol products by distillation. The process described here is a variant of the “near neutral hemocellulose extraction process” that uses the minimal amount of green liquor to maximize sugar production while still maintaining the strength quality of the final kraft pulp. Production rates vary between 2.4 to 6.6 million gallons per year of acetic acid and 1.0 and 5.6 million gallons per year of ethanol, depending on the pulp production rate. The discounted cash flow rate of return for the process is a strong function of plant size, and the capital investment depends on the complexity of the process. For a 1,000 ton per day pulp mill, the production cost for ethanol was estimated to vary between $1.63 and $2.07/gallon, and for acetic acid between $1.98 and $2.75 per gallon depending upon capital equipment requirements of the new process.To make the process economically attractive, for smaller mill sizes the processing must be simplified to facilitate reductions in capital cost.

Documents:

BioRes_05_2_0525_Mao_GVP_Kraft_Mill_Biorefinery_Acetic_Acid_Ethanol_723 (application/pdf)