Pretreatment The Key Process Step World Congress on Industrial Biotechnology Montreal, June 18 th, 2013

Transcription

1 Pretreatment The Key Process Step World Congress on Industrial Biotechnology Montreal, June 18 th, 2013 Barry Wortzman Vice-President, GreenField Ethanol Inc.

2 Pretreatment The objective of pretreatment is to recover the highest amount of available sugars, in their cleanest form, for optimal downstream hydrolysis and fermentation, to produce a variety of biofuels and other bio-based chemicals. Maximum yield of highly reactive sugars is the goal. But - Technical efficiency isn t enough. Commercial sustainability requires that operating and capital costs be reasonable. With the development of enhanced performing next-generation enzymes and yeasts, loading costs aren t the challenge they were as recently as a few years ago. Not so with equipment, where cost continues to be a huge challenge. At GreenField, we speak from experience. 2

3 Our Experience We pioneered two-stage pretreatment to efficiently process more challenging higher lignin feedstocks. It involves cooking the biomass in 2 steps: In the 1 st step - under less severe conditions, hemicellulose (C5) sugars are liquefied, separated and recovered so they don t compromise reactivity of the cellulose (C6) sugars. In the 2 nd step - under more severe conditions, the cellulose fraction is exposed and highly digestible C6 sugars are recovered. We consistently achieve the following results at pilot scale, on a batch basis, using agricultural residues, energy crops and wood: from pretreatment - an average recovery of 89% of available C5 and C6 sugars from hydrolysis - an average conversion of 87% of these sugars to fermentable monomers from fermentation - an average yield of 310 L/MTDM and most recently, 340 L/MTDM from poplar (79 L/MTDM from C5 sugars only). Of our 11 process patents filed - 2 have been granted in the US; 5 have been granted in Canada; and 5 are currently in National Phase (Patent Cooperation Treaty) prosecution. 3

4 Our Experience (Cont d) All that said, we needed Capex efficient equipment to duplicate these results on a continuous - and most importantly on a commercially sustainable basis. We couldn t rely on complicated and expensive equipment trains supplied by others. We had to develop our own simpler, less capital intensive equipment. And - we did: specially designed Filter Plates that substantially modify the functionality of a Twin Screw Extruder. On filing for IP protection we were advised by the Patent Office that there was no competing art. That patent - our 1 st Extruder patent - is currently in National Phase (PCT) prosecution covering 54 countries. Numerous trials have generated and will continue to generate follow-on patent filings. 4

5 Schematic of Filter Block in 1 st Extruder Patent Standard Extruder Block Separation Module Chamber Plate Pack 5

6 Our Equipment We spent the 2 nd half of last year and the 1 st Quarter of this year installing our 2-stage Extruder equipment into our 1 MTPD Pilot Plant with the capability to operate on a continuous basis. A representational schematic of the Flow Sheet is set out in the next slide. 6

7 Schematic of Two-Stage Pretreatment Process Flow Extruder #1 1 st Stage Extruder #2 2 nd Stage 7

8 Our Equipment (Cont d) Simply put: At the outset, the 1 st Extruder: - conditions the biomass then removes any resins and toxins (e.g. in poplar). The 2 nd Extruder completes the process by: - washing the cellulose and hemicellulose fractions - squeezing and separating the hemicellulose fraction from the cellulose fraction, and - contributing to the cook of the biomass while applying shear, to make the cellulose fraction more digestible. 8

9 Equipment is Unique & Versatile It performs these multiple functions with fewer pieces of equipment for a reduced capital cost. And - does so with less energy, enzyme and yeast loads for a reduced operating cost. Key operating parameters Other Commercial Our Modified TSE for Interstage Washing - Solid/Liquid Separation Off-the-shelf Equipment Piece(s) of Equipment required 1 3 to process 10% DM Feed Modified TSE Drainer screw Single screw press Modular screw device Screw (#) 1 x 2 3 x 1 Shearing Yes No Pressure (psig) 2, Pore size (sq in) 1/8,000 th 1/80 th Porosity (%) 25% 25% Discharge (% DM) 60%-70% 45%-50% Suspended solids (% DM) in discharge <1% 3% 9

10 Equipment is Unique & Versatile (Cont d) Uniqueness of twin screws: Self Wiping Intermeshing Screws - No viscosity or stickiness limitations. - Maximum mixing. - Contributes to a pressure seal between distinct process zones. Modularity - Multiple physical processes can be created within the Extruder. - Generates a specific pressure profile by using the right combination of elements for the biomass and the application. - Washes, squeezes and mixes in one unit. - Creates a dynamic back pressure device within the Extruder by using reverse conveying elements - do not have to rely solely on compression ratio to get squeezing action. - Can create our own distinct elements to optimize the process e.g. special mixing, cutting or backpressure elements. - Is already made for high pressure (1,500 to 2,000 psi) applications, no need to re-invent. - Can easily line the barrels for corrosion resistance if required. 10

11 3D Animation Continuous Pilot 11

12 Installed Extruders Extruder #2 Extruder #1 12

13 Our Continuous Pre-treatment Pilot Plant in Chatham 13

14 Process Versatility Our Extruder technology has 2 distinct commercial platforms: as a pretreatment device, it recovers clean sugars, the essential building block for a variety of bio-based chemicals from transportation fuels to foams and resins. as a dewatering/solid-liquid separation device, it has multiple industrial applications including - extraction of oil from plant seeds, - extraction of sugar from sugar beets, and - dewatering municipal sludge and sludge from pulp mills. We are continuing to optimize the equipment at Pilot scale on both platforms. 14

15 Next Steps At the same time, we are completing the design and engineering for a scaled up demo unit. It will be: skid-mounted and portable to demonstrate capability in-the-field (e.g. at a pulp mill, municipal sewage plant, or farm), and operational by the beginning of next year. We are actively collaborating with METSO to accelerate this project and follow-on commercialization. 15