Sarker Tumpa R, German Castaneda S, Borugadda Venu Babu, Meda Venkatesh, Dalai Ajay K
Department of Chemical and Biological Engineering, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
Department of Farm Power and Machinery, Bangladesh Agricultural University, Mymensingh, Bangladesh.
Heliyon. 2023 May 16;9(6):e16359. doi: 10.1016/j.heliyon.2023.e16359. eCollection 2023 Jun.
Torrefied pellets have gained more commercial importance due to their excellent performance in combustion, co-firing and gasification. The present investigation provides a conceptual design for torrefied fuel pellets production via combined torrefaction and pelletization technologies with and without additives. The entire design contains torrefaction unit, grinding, preparation of pellet formulation, pelletizing, and finally cooling of pellets. Two scenarios, scenario 1 (pelletization of torrefied biomass with additives) and scenario 2 (pelletization of torrefied biomass without any external additives) were tested and compared. The economic analysis suggests that both scenarios are profitable. Both scenarios were simulated using Aspen plus™, and economic feasibility was estimated using a complete cash flow analysis for a base case plant with 40,080 tonne/y capacity. For both cases, a discounted cash flow is a useful tool for estimating the minimal selling price for torrefied pellets as well as the capital investment, production cost and operating costs. The cost of the reactor used for torrefaction was found to be the most important component of combined torrefaction and pelletization system. The lowest selling price of generated torrefied pellets was found to be $103.4 and $105.1 per tonne at the plant gate for scenarios 1 and 2, respectively. Sensitivity analysis shows that, among all variable costs, labor cost has the highest influence on both net present value (NPV) and minimum selling price (MSP) in making pellets for both the scenarios. Furthermore, the internal rate of return was found to be25% and 22% at 10% discounted cash flow rate for scenarios 1 and 2, respectively. The framework that was created was found to lessen over-dependence on wood or fossil fuels and facilitate the promotion of bioenergy in rural areas.
由于其在燃烧、混烧和气化方面的优异性能，烘焙颗粒已具有更高的商业重要性。本研究通过结合烘焙和制粒技术，在添加和不添加添加剂的情况下，为烘焙燃料颗粒的生产提供了一种概念设计。整个设计包括烘焙单元、研磨、颗粒配方制备、制粒，最后是颗粒冷却。测试并比较了两种方案，方案1（添加添加剂的烘焙生物质制粒）和方案2（不添加任何外部添加剂的烘焙生物质制粒）。经济分析表明，两种方案都有利可图。使用Aspen plus™对两种方案进行了模拟，并通过对一个年产能为40,080吨的基础工厂进行完整的现金流分析来评估经济可行性。对于这两种情况，折现现金流都是估算烘焙颗粒最低销售价格以及资本投资、生产成本和运营成本的有用工具。发现用于烘焙的反应器成本是烘焙和制粒组合系统中最重要的组成部分。在工厂门口，方案1和方案2生成的烘焙颗粒的最低销售价格分别为每吨103.4美元和105.1美元。敏感性分析表明，在所有可变成本中，劳动力成本对两种方案制粒时的净现值（NPV）和最低销售价格（MSP）影响最大。此外，在10%的折现现金流率下，方案1和方案2的内部收益率分别为25%和22%。所创建的框架被发现可以减少对木材或化石燃料的过度依赖，并有助于在农村地区推广生物能源。
