Indrasukma Permanadewi, Ahmad Febry Ibrahim, Syifa Azzahra Putri Solihin, Rizky Aldiansyah

Alternative Design of a Pneumatic Conveying Machine for Rice Husk as A Coal Substitute for Rotary Kiln Fuel in Cement Factories

Introduction

Alternative design of a pneumatic conveying machine for rice husk as a coal substitute for rotary kiln fuel in cement factories. Design an efficient pneumatic conveying system for rice husk (7 tons/hour) as a sustainable coal substitute for rotary kilns in cement factories, reducing costs and environmental impact.

Abstract

The reduced amount of coal transported to cement factories is being diverted to rice husk, which is biomass, to facilitate the use of increasingly expensive coal. This transition is necessary due to the different characteristics of rice husk compared to coal. Additionally, the combustion process in rotary kilns requires extremely high temperatures (1,400–1,500°C). However, a significant portion of the generated energy is lost through the kiln walls, exhaust gases, and heat radiation. These heat losses reduce thermal efficiency and increase fuel consumption. Coal, fuel oil, and natural gas are the primary energy sources for cement kilns, which are not only expensive but also have negative environmental impacts. The fluctuation in fossil fuel prices further affects overall cement production costs. To address these challenges, cement factories must design an efficient rice husk conveying system from storage to the rotary kiln. Transporting rice husks with air ensures no unintended reactions while allowing smooth flow through closed horizontal and vertical transport pipes commonly used in the industry. This study aims to design a pneumatic conveying machine with a closed air pressure system to transport biomass (rice husks) at a capacity of 7 tons/hour as an alternative fuel for rotary kilns in the cement industry. The design method follows several stages, including practical work experience, literature review, material selection, design considerations, conceptual design, calculations, and technical drawings. The proposed system utilizes the dilute phase method, with a blower power of 49.26523 kW pushing the rice husks toward the hopper. The pipeline flow parameter, measured as the pressure drop, is 132.9673 kPa. The selected materials include galvanized iron pipes with two elbows to connect horizontal and vertical sections.

Review

The paper addresses a highly pertinent challenge in the cement industry: the escalating costs and environmental impact associated with traditional fossil fuels like coal, fuel oil, and natural gas. By proposing an "Alternative Design of a Pneumatic Conveying Machine for Rice Husk," the authors directly tackle the need for sustainable fuel alternatives. The abstract highlights the critical shift towards biomass, specifically rice husk, as a coal substitute, driven by economic pressures and environmental considerations. This transition necessitates a robust and efficient handling system, especially given the distinct characteristics of rice husk compared to coal and the extreme temperatures required for rotary kiln operations. The core objective, therefore, is to design a system that facilitates this crucial fuel switch, contributing to both operational efficiency and environmental responsibility in cement production. The study outlines a systematic engineering design approach, encompassing practical work experience, literature review, material selection, design considerations, conceptual design, calculations, and technical drawings. This comprehensive methodology lends credibility to the proposed solution. A key strength lies in the detailed design parameters provided, such as the target capacity of 7 tons/hour, the selection of a closed air pressure system utilizing the dilute phase method, and specific calculated values for blower power (49.26523 kW) and pressure drop (132.9673 kPa). The choice of galvanized iron pipes with two elbows for connecting horizontal and vertical sections also demonstrates practical material and structural considerations. The use of pneumatic conveying is well-justified by its ability to prevent unintended reactions and ensure smooth material flow, leveraging existing industry practices for pipe transport. While the design presents a promising conceptual solution, the abstract primarily focuses on the design phase without mentioning any validation or experimental results. Future work could greatly benefit from prototype development and empirical testing to confirm the calculated parameters and evaluate the system's real-world performance, including aspects like particle attrition, wear on pipes, and actual energy consumption under operational loads. Additionally, an in-depth economic analysis comparing the total cost of ownership (installation, operation, maintenance) of this pneumatic system against conventional conveying methods for rice husk, and its overall contribution to cost savings compared to fossil fuels, would significantly enhance the paper's impact. Considerations regarding the long-term reliability and maintenance requirements of the system, especially with abrasive biomass, would also be valuable additions for industrial application.

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