A New Method of Producing Bio-Energy by Using Sugar- Beets

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1 Available online at Energy Procedia 12 (2011) ICSGCE 2011: September 2011, Chengdu, China A New Method of Producing Bio-Energy by Using Sugar- Beets Guang-Qi Zhou *, Guo-Fu Zhang, Dong-Mei Qi School of Biological Engineering of Dalian Polytechnic University, Dalian , China Abstract A patented technology of ethanol production by sugar-beets is introduced in this paper. After squeezing the juice of sugar-beets, by multi-effect evaporation, high sugar solution could be acquired and infection microbes could be killed at the same time; recycling impregnating sugar-beets and adjust sugar concentration to 26% by waste from distillation to improve the efficiency of fermentation and distillation. Raw material prices and evaporation energy are the main economical influencing factors to the new technology. Compared with the traditional production methods, patented technology can generate significant economic benefits Published by Elsevier Ltd. Open access under CC BY-NC-ND license. Selection and/or peer-review under responsibility of University of Electronic Science and Technology of China (UESTC) Keywords: Sugar-beet; Ethanol; Concentration; Process. 1. Introduction The oil consumption of China increases 13% every year, whereas energy production only meets 70% of the domestic needs. China is one of the largest oil importers in the world [1]. Since "the state 'the tenth five years' national development program", China has remodeled and built a few technologically advanced fuel-alcohol big projects, in order to develop the fuel ethanol by the way of "first carrying out experiments and then promotion"[2]. These big projects include Jilin Fuel Alcohol Company Limited (600 thousand tons/year), Henan Tianguan Group (300 thousand tons/year), Anhui Fengyuan Biochemistry Incorporated Company (320 thousand tons/year), Heilongjiang Huarun Alcohol Limited Company (100 thousand tons/year), and so on. Currently, the total production capacity of more than 100 enterprises in the industry reaches 3million tons [3]. It is estimated that the total alcohol production volume will reach 4million tons country-wide in 2015, of which contains 3million tons commodity * Corresponding author. Tel.: address: dlzgq@126.com Published by Elsevier Ltd. Selection and/or peer-review under responsibility of University of Electronic Science and Technology of China (UESTC). Open access under CC BY-NC-ND license. doi: /j.egypro

2 874 Guang-Qi Zhou et al. / Energy Procedia 12 (2011) alcohol (<National Alcohol Industry the Tenth Five Years Development Plan and 2015 Plan (draft) >). Sugar-beets and sugarcane are the world's main materials for producing sugar. The major sugar in sugar-beets is sucrose. Besides, there is a little other carbohydrate and pectin. Former Soviet Union and Eastern Europe once used surplus sugar-beets or frozen and perishable sugar-beets for alcohol production. In the past, China used the molasses (by-products) from sugar-beets sugar process to produce alcohol or other bio-fermentation production. Sugar content in molasses (beet) is about 50% and the major composition is sucrose [4]. The sugar-beet planting areas in China mostly spread in Northeast China, North China, Northwest China inland and the border areas. Due to the effects of soil, sunlight and temperature difference between morning and night, the sucrose content is from 12% to 17%, which can be directly used by yeast. Since the state the eleventh 5 years plan", China has implemented the food security strategy and encourages using the non-food raw materials (Cassavas and Sweet sorghums) to replace the amyloid Corns and Sweet potatoes [5] for producing alcohol [6] [8]. This patented technology is a process of alcohol production by using sugar-beet as raw materials and hopes to provide a new way for producing new bio-energy. 2. Research Methods This patented technology provides us a new way of producing alcohol by sugar-beets (Fig1 process B) : Firstly, squeezed out the sugar solution in sugar-beets and then vacuum enriched part of the sugar solution; before fermentation, regulated initial sugar solution content to the optimal level for yeast fermentation by the low concentration of squeeze juice or distillation wastewater and then fermented fast and continuously; fuel alcohol can be obtained after a multi-tower pressure distillation and products are isolated as well; sugar-beet pulps can be used as feed or degradable materials. The implementation process is: 1) Clean sugar-beets and cut into shreds. After squeezing or retting the first-time sugar solution, the solution content is above about 15%; the wastewater from the bottom of distillation column is taken for partial reflux and dipping the sugar-beet pulps, then the solution and residue are isolated by press filter or centrifuge. The second-time sugar solution content is about 3% to 8%; the separator solution then goes into the enrichment process. Enrichment time must be more than 40 minutes and the temperature must not be lower than 65. Concentrated the solution to 26%-60%which is defined as concentrated liquid and then cooled to and stored in normal temperature. The residues can be used as feed or other comprehensive utilization. 2) Add the concentrated liquid into the dilute sugar solution or distillation wastewater to regulate the sugar content to 18%-26% with water and regulated ph to with acids, then pump the solution into the fermentation bioreactors continually; the delivery pipelines and fermentation system must be sterilized in advance. 3) Pump the patented yeast into the fermentation bioreactor and input sterile air intermittently for ethanol fermentation. The fermentation temperature is and the fermentation period is 20h-45h. The alcohol content in broth can be 9%-14% (V/V). 4) Differential pressure distillation and molecular sieve method are used for isolating high purity alcohol; the wastewater from the bottom of the distillation column is still recycled for concentrating the sugar solution or retting the sugar-beets. 3. Cost and Profitability Analysis Comparison with the traditional way of ethanol production by molasses, changes in costs are mainly caused by the concentration process of sugar-beet juice, while fermentation and distillation process stay the same as before. However, the initial syrup content was improved to a fixed concentration (18% - 26%) precisely because the process B had been taken, which greatly improved the efficiency of fermentation

3 Guang-Qi Zhou et al. / Energy Procedia 12 (2011) and at the same time made the production process run more smoothly and easier to control. Table 1 is the cost estimation for the tons of ethanol. Table 1: Cost estimation per ton of alcohol (96 ) (B process) Name Amounts ( ) Remarks Sugar-beets Purchase price of sugar-beets is 250 Yuan per ton, per ton alcohol consumption of sugar-beets is 13.2 ton. Auxiliary materials 60 Including enzymes, acids, etc. power 130 Per ton of alcohol power consumption is about 160kw. h, steam 4t water 15 Per ton of alcohol water consumption is about 15t. labor cost 100 Equipment depreciation 10 taxes consolidated tax rate is about 9.5% Other expenses 50 Including management, wastewater treatment, etc. total 4200 Comparing tons of ethanol output data in Table 1 with those in Table 2 (according to 2009 market prices), per ton ethanol (96 ) may gross 2051RMB Table 2: per ton of alcohol (96 ) output (at 2009 market prices) name amounts ( ) remarks alcohol (96 ), t 5500 Sugar-beet pulps % of the total sugar- beets, 50 /t (wet) Dry yeast 20 CO 2 (putiry99%) % of the total ethanol output, 500 /t. Other by-products 50 Fusel oil and so on. total Discussion Economic benefits of ethanol plants primarily depend on materials, energy and resources, labor cost and investment in equipment and wear and tear, etc. In this article raw material sugar-beets and multieffect evaporation process are the major factors in the costs change. Although the costs of direct fermentation of sugar-beet juice (adjust the sugar content by adding molasses) is lower than that of sugarbeet juice concentration (B process), the multi-effect evaporation acquires a high-sugar fermentation and saves distillation and equipment costs [9]. At the same time, it also reduces the microbial infection of the squeeze juice. Part of impregnated water and diluted water are the waste from the distillation tower. Water can be recycled in the production process and reduce emissions. In addition, with this method, separating sugar-beet pulps before fermentation improves the equipment utilization of fermentation and

4 876 Guang-Qi Zhou et al. / Energy Procedia 12 (2011) distillation, saves energy consumption and makes the comprehensive utilization of sugar-beet pulps much easier. Enrichment process reserves the sugar, which will be able to extend the production period in ethanol plants. Flow chart of producing alcohol by using beet (A) Sugar-beets Dry sugar-beets Water from deep well Pretreatment Crushing Cut into shreds Feed or degradable materials Extraction tank Water from deep well pulverization Sterilization Steam Molasses Regulate ph3.5 with Sulfuric acid Drying Recycling (hot) Cooling Sugar-beet wet pulps Waste Yeast Anaerobic fermentation Industrial alcohol with a high Aldehyde ester fraction Squeeze or centrifugation Distillation CO 2 Fusel oil Edible alcohol or fuel alcohol waste liquid Flow chart of producing alcohol by using beet (B) Sugar-beets Dry sugar-beets Water from deep well Pretreatment Crushing Soften pure water Cut into shreds Squeeze or centrifugation Wet pulp Extraction Recycling distillation wastewater (hot) Complex enzyme Second-time sugar First- time sugar solution Sugar-beet pulp Concentration and sterilization Steam Drying Crumbing Cooling Patented feast Fermentation CO 2 Superior Edible alcohol or fuel alcohol Industrial alcohol with a high Aldehyde ester fraction Feed or degradable materials Distillation Fusel oil Waterwaste Fig. 1. The conventional beet ethanol production process (A) and the patent process (B) comparison

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