Teknisk utvärdering av en ny miljövänlig förbehandlingsmetod av biomassaavfall med utspädd salpetersyra

University essay from Högskolan i Borås/Institutionen Ingenjörshögskolan; Högskolan i Borås/Institutionen Ingenjörshögskolan

Abstract: Bio-refining of renewable resources such as waste biomass into value added products has increased rapidly over the last decades. The aim is to find new environmentally friendly yet economically feasible ways of replacing current utilization of non renewable resources. It can be expected that a commercially viable next generation bio-ethanol will be produced from lignocellulosic feedstock in the near future.This master thesis set out to look at a specific Canadian company in depth (Pure Lignin Environmental Technology Ltd), known as PLET henceforth. PLET has a new approach in pre-treatment of biomass, with a recently patented environmentally friendly technology, which could be extremely lucrative if applied in the right context. It is desirable to look at the possibility of using the master thesis as a take-off platform to launch a consulting bio-tech company directly after completion.There are several different ways to process biomass into higher value added products. In this master thesis focus is laid upon biomass waste, but the same principles could be applied on biomass processing in general. That is the separation and purification of products. In order to put the technology of PLET into a context, other company approaches are used as a comparison, such as SEKAB E-Technology, Lignoboost and Borregaard Lignotech.It is however hard to find suitable examples equivalent to the PLET approach since the technology of PLET considers all the three constituents of wood as raw material for production of three stand alone commercial products; pure lignin, pure cellulose and hemi-cellulose. These three products are separated and purified in the pre-treatment process at high yield and practically no formation of by-products. Process parameters are only moderately adjusted depending on what raw material is used.The catalytic reactor process (=CRP), is performed by PLET as a pre-treatment in a continuous and batch system, in which lignocellulosic material (= wood chips, saw dust or other waste biomass) undergo acid catalyzed hydrolysis by dilute nitric acid. The impregnated wood chips are partially depolymerised from the lignin matrix when heated in the low pressure catalytic reactor. After that, follows distillation, condensation and almost complete recovery of dilute nitric acid. After CRP, the cellulose pulp is separated from the black liquor by an alkaline solution (=NaOH). The obtained black liquor is pumped to a separation tank to precipitate lignin and sweet liquor through filtration. The final step is to dry the lignin, while the sweet liquor is utilized by Torula yeast (=Candida utilis) in order to produce unicellular protein.It would be interesting to see if the pre-treatment that PLET provides, could be exploited in a context of production of next generation of cellulosic ethanol from the cellulosic part of waste biomass. In this master thesis, an evaluation of producing next generation ethanol from dilute-nitric acid pre-treated cellulose rich softwood was performed and dilute sulphuric acid pre-treated hemi-cellulose rich hardwood birch pulp was used as a comparison.The technical part of this master thesis was conducted on a laboratory scale, using samples from two companies, referred to as PLET and SEKAB E-technology (Sweden). The strategy of PLET is currently to find a commercial platform to produce value added products from waste biomass generated by saw mills and pulping industries, while SEKAB E-Technology mainly works with Swedish softwood as a raw material.ivExperiments of this master thesis includes a series of fermentation trials using either SSF (= Simultaneous Saccharification and Fermentation) or SHF (= Separate Hydrolysis and Fermentation). Yields of the enzymatic hydrolysis and subsequent fermentations were estimated with HPLC measurements complemented with dry weight measurements.Obtained experimental data support the potential to make lignocellulosic ethanol out of either softwood or hardwood. Ethanol yield from dry material from SEKAB E-Technology hardwood birch slurry was 0.43 (g ethanol / g dry raw material), whereas samples supplied by PLET achieved the following results. The ethanol yield from dry material from softwood pine washed cellulose was 0.33 g (ethanol / g cellulose). The ethanol yield from dry material obtained for softwood pine unwashed cellulose in the three SHF was 0.47; 0.34 and 0.19 (g ethanol / g cellulose) respectively, while the yield in the two SSF was 0.45 and 0.46 (g ethanol / g glucose).The economical part of this master thesis includes the use of Business Model Canvas and the NABC- model (= Need, Approach, Benefit and Competition) to define the basic topics and tasks that need to be addressed in the start up phase of a small consulting bio-tech company.At least 6 million US dollars is needed as a minimum starting capital to be able to construct a small commercially viable pilot plant, according to PLET. This investment would cover the basic requirements and is scalable. The construction could preferably be done in Sweden in the vicinity of an existing saw mill or paper pulp industry or elsewhere, where a steady supply of cheap raw material could be assured. The size of the operation envisioned, depends greatly on location and adjacent businesses. Large pulp mills in the range of 400-500 MWh would be preferred, the largest pulp mills in Canada process 5000 ton per day which is equivalent to a capacity of 1 GW wood per day (GW = giga watt), but the concept of the technology of PLET must first prove its value on a smaller scale.According to PLET, a future full scale production plant could be designed for processing 56 tons of wood chips per day of wood chips would generate annual revenues of ≈ 7500000 US dollars. The annual profit would be ≈ 2500000 US dollars, and capital cost (equipments) ≈ 5000000 US dollars, while the payback time on investment would be 2-3 years. According to PLET, the products are estimated to have the following values; 25 tons/day of pure cellulose with a market value of 400-500 US dollars/ton, 10 tons/day of pure lignin with a market value of 1000-1200 US dollars/ton and finally 21 tons/day of sweet liquor with a market value of 50-100 US dollars/ton.

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