پالایشگاه زیستی

Using new solutions to convert biological waste into valuable products can prevent wastage of capital while managing waste. Wheat straw is one of these biological wastes. In this research, with this aim, wheat straw was investigated as a raw material for the simultaneous production of paper and bioethanol as valuable products. First, the test was performed by applying hot water pre-extractions at 70 degrees Celsius for 45 minutes with the ratio of cooking liquid to wheat straw, and alkaline pre-extractions at 70 degrees Celsius for 30 and 45 minutes with Alkalinity of 8 and 12 took place, these conditions were selected from among the various experimental tests that were investigated. Bioethanol production was done using anaerobic fermentation method, so that inside the 2 liter reactor, liquor obtained from 50 grams of wheat straw was added, and then in order to carry out the fermentation process properly, the amount of sugar inside the reactor was added to Vsuger/Vtotal 62. 15.0%, Vp/Vsuger 2.33% of the amount of peptone sugar, Vm/Vsuger 1.5% of the sugar amount of Saccharomyces cerevisiae yeast was added. In the next step, HPLC test, flame test and calorific value were checked for different conditions in order to report the suitable conditions for bioethanol production. According to the results of the pre-extraction method with hot water compared to alkali under the same test conditions, it has more favorable results in terms of ethanol production due to the maintenance of suitable conditions for the activity of microorganisms. According to the results for all samples, the quality of produced paper was in favorable conditions. On the other hand, pre-extraction with hot water is more favorable compared to the two samples of pre-extraction with hot water and because it has a high flame height, high calorific value and high quality ethanol; that this sample can be indicative of suitable conditions for use. In this research, the objectives of the experiment were investigated based on experimental tests, and then the results were analyzed based on different methods.

In this research, in order to maximize the use of wheat straw, the possibility of simultaneous production of ethanol and paper from it was investigated in different conditions of treatment with hot water and alkali, and according to the results of the experiment presented in chapter four, it was observed that using hot water In addition to paper production, it is possible to produce ethanol from straw, and this study showed that ethanol production with hot water can only be produced by destroying the tissues of straw, considering the preservation of the activity conditions of microorganisms, especially the pH. It is desirable that ethanol helps and this method is better in comparison with the pre-extraction method with alkali. Among the different methods of pre-extraction with hot water, 1.10 and 1.12 treatments had more suitable results, and the use of these methods is recommended. However, more strictly if a comparison is made between these two treatments.

According to the results of Hplc, calorific value test and flame test, it can be seen that due to the relatively high calorific value and flame height in the hot water treatment sample of 1.10, the use of this compound in cases that are more for combustion in Fuel compounds (both engine and...) are of higher quality and more suitable; But with a quantitative perspective and the use of ethanol for various uses (such as: dyeing and chemical industries, etc.) where the high yield of ethanol production is more desirable, the use of hot water treatment solution 1/12 is also recommended. Today, instead of using fossil energy sources, attention is paid to the use of lignocellulosic materials as the most important sources of biomass in the world, which have a huge potential to produce value-added products such as biofuels. This can be achieved with the biological establishment of bio-refinery units in various industrial sectors, including pulp and paper factories. Biomass includes the synthetic function of nature and has a different proportion of carbon, hydrogen, oxygen and nitrogen compared to oil. Biomass conversion by biotechnological methods along with chemical conversion will play a big role in the future. Plant biomass always includes basic carbohydrate products, lignin, fat protein and a variety of substances such as vitamins, color, taste, aromatic essences with very different chemical structures. A bio-refinery is a place that, through a process using mechanical, thermal, chemical and biochemical methods, converts biomass into products with high added value or key intermediate products for the production of chemicals and other materials. Today, many pulp and paper factories in the world have suffered a decrease in profitability due to factors such as increased competition, the high cost of supplying raw materials and the energy consumption of the factory. One of the solutions to overcome this problem is to diversify the products of the factory, in this direction, hemicelluloses and dissolved lignin can play an important role and move the pulp and paper factory towards the production of green fuels and Conduct biological materials. Biofuel of the new generation creates changes in weather conditions. This action is done by reducing the emission of greenhouse gases. For example, bioethanol produced from wheat straw releases only 20 grams per kilogram during its life cycle, while 163 grams per kilogram is released for gasoline on average. Reducing the pressure on food products, which is done by developing other fuels from non-food raw materials and the rest of agricultural products, in addition, they can use waste products as raw materials. Therefore, it causes the reduction of agricultural waste buried in the ground or exposed to other mechanisms. Unlike fossil fuels, biofuels are produced from renewable sources. They emit less pollutants than fossil fuels because ethanol burns completely, reducing carbon monoxide emissions. Due to the release of carbon dioxide and the absorption of raw materials, they do not contribute to the warming of the earth, and they are more economical compared to fossil fuels.One of the most important fuels produced by biological methods is bioethanol. The production of ethanol from lignocellulosic biomass is known as the second generation of production, and compared to its production from sugars and starch (the first generation of production), it has more energy, economic, environmental, and even social political benefits, and considering the significant benefits Lignocellulosic materials, the focus of researchers and companies is directed towards the use of lignocellulosic biomass.

Waste can be described as any type of material or object that has no other use and is to be thrown away. Perspective, the generation of waste materials is unavoidable in a consumption-based society, and it makes waste management a major challenge considering the huge amounts of waste produced globally. In fact, in 2014, about 2.6 billion tons of waste was generated in the European Union (EU), of which 41% was disposed of in landfills, 36% was recycled, 10% was used in excavation operations, 7% was treated in sewage treatment plants and the remaining of 6% was burned for creating energy or oxidation and stabilization of waste. Accordingly, in recent decades, humanity has changed its focus on traditional waste management from the concept of "collection and disposal" in favor of hierarchical management of waste to increase sustainability.Nevertheless, even when environmentally friendly practices such as recycling and reuse are carried out, many operations are "downcycling", meaning that the recycled product has less economic value than its original objective, and is not as valuable as the original product made from strong raw materials. In this way, the linear economy model based on the pyramidal hierarchy of waste materials, which is used today, also has limitations. Indeed, there are still opportunities to increase productivity in many industrial processes, but these gains are likely to be increasingly marginal and undifferentiated. Therefore, the future acceptance of the circular economy concept, as opposed to the current linear model, is a necessary paradigm shift. This new concept is increasingly considered a source of innovation in products, processes, and business models and opens up great opportunities that should be used by companies and organizations as competitive advantages in a dynamic market to be used globally. The processing of raw biomass to produce energy, fuel and chemicals through a combination of different applied technologies is considered a promising path to achieve sustainable waste management, with many environmental and economic benefits. The main processes related to energy recovery and biofuel production are considered under the concept of biorefineries. This waste biorefineries are facilities that integrate the necessary technologies to convert biomass feedstock and other waste into usable products, ensuring that the circular economy moves from theory to the real world. Existing waste streams can be converted to biofuels (waste-to-liquids, WtL) or energy (waste-to-energy, WtE) technologies, both of which are expected to be a key element in future waste management. In general, energy and biofuel production technologies from waste are classified into three main thermochemical, biological and chemical processes. Thermochemical technologies include processes of combustion/incineration, gasification, steam explosion, pyrolysis, hydrothermal liquefaction, and torrefaction; biological technologies include the processes of anaerobic digestion, fermentation, enzyme purification, and microbial electrolysis, and chemical technologies include hydrolysis, solvent extraction, transesterification, and supercritical conversion.

The present research is a descriptive-review study whose data was obtained through library studies and various sources were used to process the material. Considering the importance of biofuels as a source of renewable energy, we tried to use as much as possible the most relevant and up-to-date sources containing valuable points regarding the types of energy and biofuel production technologies from biomass. In this review article, the possibility of using the remaining post-processed waste as available and low-cost bio-renewable resources in waste bio-refineries has been investigated. Waste biorefineries are facilities that integrate the necessary technologies to convert biomass feedstock and other waste into usable products, ensuring that the circular economy moves from theory to the real world. Existing waste streams can be converted to biofuels (waste-to-liquids, WtL) or energy (waste-to-energy, WtE) technologies, both of which are expected to be a key element in future waste management. Accordingly, in this paper, we briefly study the current status of the main WtL and WtE technologies in order to use them as a tool for the management of residual post-processing wastes and by-products resulting from them, and finally about Future developments on the mentioned technical options are briefly discussed.

In this review research, the possibility of using the remaining waste after processing as abundant and low-cost bio-renewable resources in waste bio-refineries in the future was investigated. Existing waste streams have a complex and diverse composition according to their source, which require new logistics platforms of classification and valuation. With the exhaustion of the linear economy of "collection and disposal", new methods of waste management are inevitable in the long term. In this way, waste biorefineries that generate green energy and produce virtual products with high value and zero waste (no waste) in a "closed loop" and "up-cycling" approach are the "landfills" of the future. It is expected that they will be very important and vital in bringing sustainable waste management into the real world that will allow transformative economic growth under the concept of circular economy. However, from the technologies reviewed, it can be concluded that individual WtL and WtE processes are almost always limited in their scope and produce multiple unwanted products. In this regard, the gasification process is largely considered a technology with greater potential and scope in individual applications. However, even this process has drawbacks such as reactor design, feed system, and bitumen production that require costly post-treatment and/or further technical improvements. In contrast, the combination of several WtE and WtL processes in an integrated waste biorefinery allows reducing and eliminate the drawbacks of each process. For example, in gasification, some of the unwanted materials produced may be used and valued by further chemical processing, and even syngas can be upgraded. This new pyramid of waste valorization creates opportunities for specific technologies such as explosive depressurization and drying to become practical applications by reinforcing other well-established technologies in an integrated approach. Future research should primarily focus on establishing a hierarchy of processes to produce the highest value products, and then gradually progress to low-cost products and energy production. However, for this vision to become a reality, an increased effort by researchers is required with continued and sustained support from all potential stakeholders. More pilot or semi-pilot scale demonstration projects should be realized in the coming years, focusing on aspects such as energy balance and cost-benefit analysis that will ensure the viability of the proposed solutions