مجله صنایع چوب و کاغذ ایران
سال چهاردهم شماره 3 (پاییز 1402)

The use of biomass energy as a source of renewable energy, in addition to reducing environmental problems and global warming, ensures energy security. Fuel briquettes are solid biofuels that are obtained by simple densification processes and do not require complex physicochemical treatments. In this research, the potential of using lignocellulosic residues such as paulownia, corn stalks, and recycled paper pulp to produce fuel briquettes without binders at low pressures of 9, 18, and 27 MPa, at two temperature levels of 75 and 100 degrees Celsius, was investigated. The results confirmed the feasibility of producing fuel briquettes from these three lignocellulosic materials with appropriate physical and mechanical characteristics. For recycled paper pulp briquettes, higher density and compressive strength were obtained at low pressures, while Paulownia and corn stalks required higher levels of pressure, temperature, and time to achieve desirable density and compressive strength compared to recycled paper pulp.

In this research, the fabrication of fuel briquettes using two types of rapeseed and bagasse biomass with submicron cellulose as a natural fibrous binder with 6, 9, and 12% has been investigated. Then, fuel briquettes were prepared under conditions included 150 °C and 100 MPa pressure. In order to evaluate the performance of briquettes, the density, compressive strength, crushing resistance and calorific value of the prepared samples were measured. The amount of compressive strength in milled bagasse briquettes with cellulose binder was higher than that of crushed bagasse briquettes with cellulose binder. The briquettes made from rapeseed chips also showed more compressive strength in most cases and it was enhanced with the increase of binder usage. Regarding the resistance to crushing, its value increased from about 50% in the control sample to about 99% in the briquettes made with 12% binder. Similar results were obtained in the case of rapeseed briquettes.

Nowadays, the utilization of lignocellulosic residues in the production of engineered wood products is promising for sustainable development... The purpose of this research is to investigate the properties of LSL (Laminated strand lumber) and hybrid based glulam using date biomass in the presence of two types of adhesives, i.e. epoxy and polyvinyl acetate. For this purpose, LSL was made using date palm rachis and phenol-formaldehyde resin. In order to evaluate the performance of glulam beams, physical and mechanical properties were considered. The physical and mechanical performance of glulams in the presence of epoxy adhesive was better than polyvinyl acetate adhesive. The LSL impact resistance was 6/9 J/cm.Hybrid glulams provided higher mechanical resistance despite lower density. The highest amount of flexural strength and modulus of elasticity with values of 37/3 and 7856 MPa, respectively, was related to Hybrid glulam with epoxy glue. The highest compressive strength was related to the combined glulam made in the presence of polyvinyl acetate adhesive (2/27 MPa); However, no significant difference was observed between the compressive strength of glulam beams.

In this study, the possibility of making a composite from bagasse was investigated. Bagasse-polypropylene fiber samples with different bagasse percentages (15, 25, and 35%) and coupling agent (0, 1.5, and 3%) were made, and their mechanical properties were examined. The results showed that with an increase in bagasse fibers, the flexural strength and tensile modulus did not change significantly, but the modulus of elasticity and energy at the breaking point decreased significantly, but the tensile strength increased. The results of the impact resistance test showed that although the impact resistance decreased and increased slightly with an increase in the percentage of bagasse fibers and coupling agent, this amount of decrease and increase was very small and insignificant, and the results of this test were random and unrelated to the increase in raw materials. However, in the impact resistance test without a notch, a significant difference in the decrease in impact resistance was observed with an increase in fibers and its increase with an increase in coupling agent. Overall, all measured engineering properties in this study improved, except for impact resistance, which decreased with an increase in fibers. It is suggested that to improve the engineering properties of this type of composite, the bagasse percentage and coupling agent should be increased up to 30% and 3%, respectively.

Economic growth and population growth will increase the demand for paper products, while the sources of raw materials for paper products are limited.  One of the solutions that can help preserve natural resources is the recycling of waste paper combined with advances in information and communication technology.  The purpose of this article is to estimate the demand function of recycled paper in Iran's economy during the seasonal period of the years 1379 to 1400, based on autoregressive distributed lag (ARDL).  The results show that the most important factor affecting the demand for recycled paper in the long and short term is the GDP variable, and its elasticity coefficients are estimated to be -0.46 and -0.22, respectively. With an increase in the level of economic activities, the consumption of recycled paper decreases and as a result, recycled paper is considered an inferior product. The variable of printing and writing paper is not a strong enough substitute for recycled paper as a competing product in the long term and short term with the elasticity coefficient of 0.23 and 0.13%, respectively. On the other hand, with an increase in internet users, the demand for recycled paper will increase by 0.08% in the long term. In fact, with the increase in the number of internet users and personal computers, the consumption of office paper due to online purchases and also the increase in demand in the long term for paper Packaging, carton and cardboard increases for custom items.

Wood composite products, encompassing various types of fiberboard, particleboard, and other wood composite panels, are relatively new compared to similar paper products. Despite their recent introduction, surveys indicate that they represent the country's largest consumers of wood raw materials. In recent years, due to wood resource limitations and the rapid demand for wood and wood products in the country, strategic planning to address these growing needs has become imperative. Examining and evaluating the price index of wooden products provides valuable insights into the economic status of this market. The price index in this market has exhibited inflationary trends in recent decades, highlighting the impact of these products. Based on the prevailing conditions, a suitable framework has been developed to regulate the pricing of wood programs and wood products. This preliminary research employs econometric models to investigate the relative price changes and the price index of three fiberboard products: fiberboard, particleboard from wood chips, and particleboard from bagasse. Subsequently, to eliminate inflation, the price changes of the three products are analyzed using the consumer index, producer index, and Laspeyres and Paasche methods. The results reveal an upward trend in the price index of wood composite products between 2011 and 2020. Furthermore, the relative price change over the ten-year period compared to the base year demonstrates an increase of 804%, 745%, and 711% for the relative price of fiberboard, particleboard, and bagasse particleboard, respectively. Additionally, after adjusting for general inflation based on Laspeyres' index and Paasche's index, the purchasing power for these three products increased by 694% and 763%, respectively, during the mentioned period.

In this study, a short ozonation pretreatment method was used to accelerate the extraction and purification of chemical compounds in bagasse and its unbleached soda paper pulp. In order to optimize and economize energy consumption, the operating conditions of ozonation were evaluated in three mediums (acidic, neutral and alkaline) and in different time intervals of 20, 60, 120 and 180 minutes. To investigate the effectiveness of medium and time of ozone on the chemical structure of the bagasse and its unbleached soda paper pulp, the infrared spectroscopy, X-ray diffraction, the content of the carboxyl group was used through conductivity titration and polymerization degree measurement. The results showed that the acidic medium had the highest amount of lignin removal and the least amount of cellulose and hemicellulose destruction and was chosen as the most suitable medium for the ozonation process and since the highest lignin removal occurred in the first 20 minutes reaction, so to remove lignin, the long ozone pretreatment is not required and short ozone can save energy and cost of pretreatment and in addition, cellulose and hemicelluloses destruction which are valuable compounds, are significantly reduced.

Lignin, a polymer found in wood with carbon content up to 60 %, has potential applications in producing porous carbon as an adsorbent material, but its synthesis using chemical activation requires a large amount of activating agent, which can cause production problems. To address this issue, the study examined the effect of adding acrylic acid to lignin during the hydrothermal process to reduce potassium hydroxide consumption in porous carbon production. Results showed that adding acrylic acid increased surface area from 283 m2/g to 653 m2/g, and also, the maximum lead adsorption capacity of 196 mg/g was achieved by the synthesized porous carbon.