Grantee Research Project Results

2022 Progress Report: A Green Chemistry Approach to Pulping Hemp as an Industrially Relevant Renewable Fiber for Construction

EPA Grant Number: SV840036
Title: A Green Chemistry Approach to Pulping Hemp as an Industrially Relevant Renewable Fiber for Construction
Investigators: Cai, Dr.Charles , Fernandez, Albert , Aquino, Aira , Kim, Brandon , Catapang, Marcus
Current Investigators: Cai, Dr.Charles
Institution: University of California - Riverside
EPA Project Officer: Aja, Hayley
Phase: II
Project Period: July 1, 2020 through June 30, 2022 (Extended to December 31, 2023)
Project Period Covered by this Report: July 1, 2021 through June 30,2022
Project Amount: $74,882
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet - Phase 2 (2020) Recipients Lists
Research Category: P3 Awards

Objective:

The purpose of this project is to develop a more environmentally sustainable pulping and fractionation approach called CELF (co-solvent enhanced lignocellulosic fractionation) to process newly-legalized industrial hemp in the US. Processing raw hemp stalks using CELF can utilize the entire hemp plant without decortication while producing purer hemp intermediates for new applications in green construction and green manufacturing. During the first phase of the project, our project team had successfully employed CELF pulping to decorticated industrial hemp supplied by our commercial partners. The CELF pulped hemp was then used to produce 2”x2” sized briquettes of “enhanced” hempcrete. We found that the enhanced hempcrete briquettes produced from CELF pulping was noticeably denser, harder, and less brittle than conventional hempcrete produced directly from decorticated hemp hurd. We had also simultaneously produced hemp-based resins from lignin and hemp-based sugars that could be further valorized as high value co-products, such as ethanol. As such in phase two of this project we developed the following four objectives:

• 1. Compare chemical composition of CELF pulped hemp with traditional decorticated hemp
  •  QAPP target: target 80% cellulose-fiber content in solids after pulping using NREL protocol TP-510-42620
• . Compare thermal and structural performance of CELF-pulped hemp with traditional decorticated hemp and other known materials
  • QAPP target: follow standard ASTM/ISO standards of measureme
•  Ferment hemp-based sugars from CELF pulping into fuel ethanol
  • QAPP target: target >30 g/L ethanol concentration following NREL protocol TP-510-42630
• Disseminate results to project collaborators and publish findings
  • Annual and Final report submitted to EPA, prepare manuscript for submission to peer-reviewed journal

Progress Summary:

We have completed Objective 1 and 3 during year 2 and partially completed Objective 2: while successfully achieving QAPP targets for Objectives 1 and 3. Our preliminary results demonstrated that we had achieved >80% cellulose purity in our CELF-pulped hemp stalk and hemp hurd samples. We have successfully switched to a new hemp supplier (Columbia Basin Bioscience, Oregon) and have obtained ample samples of their undecorticated hemp sticks from the stalk portion of the plant. We have constructed a thermal conductivity testing apparatus (shown in Figure 1) that will allow us to calculate the thermal conductivity coefficient k from our fabricated sample briquettes. Our current overall progress on project objectives is 75% out of 100%.

Future Activities:

The following are planned activities based on work yet to be completed for each objective:
Objective 1: This objective is completed.
Objective 2: Hire new undergraduate team and apply for access to MSE resources to perform structural and thermal testing of newly made modified hempcrete briquettes.
Objective 3: This objective is completed.
Objective 4: Submit annual and final reports. Collect significant research findings and produce a manuscript/conference presentation for submission to a peer-reviewed journal

References:

1. Cai, C. M.; Zhang, T.; Kumar, R.; Wyman, C. E., THF co-solvent enhances hydrocarbon fuel precursor yields from lignocellulosic biomass. Green Chemistry 2013, 15 (11), 3140-3145.
2. Nguyen, T. Y.; Cai, C. M.; Kumar, R.; Wyman, C. E., Co-solvent Pretreatment Reduces Costly Enzyme Requirements for High Sugar and Ethanol Yields from Lignocellulosic Biomass. ChemSusChem 2015, 8 (10), 1716-1725.

Progress and Final Reports:

Original Abstract

2021 Progress Report

2023 Progress Report

Final Report

P3 Phase I:

A Green Chemistry Approach to Pulping Hemp as anIndustriallyRelevantRenewable Fiber for Construction  | Final Report