The Department of Chemical Engineering at Mai Nefhi College of Engineering and Technology (MCET) hosted this year’s Chemical Engineering Innovation Exhibit in Asmara. The event showcased research papers by graduating students, focusing on addressing local issues in Eritrea like the problematic proliferation of non-biodegradable plastic waste, clean water wastage, potentials of herbal medicines, utilizing lime abundance in Eritrea, and energy conservation in cement factories. These projects consistently arrive at solutions that embrace a sustainable and ecofriendly approach.
The impetus behind the exhibit, as stated by the department, was to establish a platform between industry and academic research, and encourage a long-term collaboration between the two sectors. The exhibit, which was taking place outside the college for the first time, was hosted at the National Confederation of Eritrean Workers (NCEW), and was the result of joint effort of the head of department, professors, lecturers and graduate assistants of the department. The department also hosts a variety of fun, educational activities like the “Chem Fest” and other recreational events within the college to spark curiosity and maintain interest in students.
Following are the summarized version of the six research papers presented during the exhibit, four chosen from current academic year, two from last year. It is very much worth noting that so far, the Department of Chemical Engineering has published 20 research papers abroad on international science journals like Journal of Agronomy, Technology, and Engineering Management, Journal of Engineering Science, Equilibrium Journal of Chemical Engineering, Research Journal of Pharmaceutical, Biological and Chemical Sciences, Proceedings on Engineering Sciences, International Journal of Food, Agriculture, and Natural Resources, and many more.
- Medicinal Extracts from Parsley Leaves:
This study delved into the medicinal potential of parsley leaves. The researchers extracted active compounds from parsley leaves and analyzed their composition using various spectroscopic techniques.
By carefully analyzing the extracts, the researchers sought to identify the specific ingredients responsible for the plant’s medicinal properties. These properties can be quite diverse in their healing powers, ranging from antimicrobial (hindering the growth of bacterial infections) to antioxidant (protecting body cells from damage) and potentially antidiabetic (regulating blood sugar). Although the antidiabetic properties hold the most promise, the findings also revealed that the antimicrobial properties of the parsley extracts were comparable to those of the commercially manufactured antibiotic Amoxicillin.
The findings suggest that parsley extracts could be a promising source of natural remedies for various health conditions. This research aims to establish efficient methods for extracting and analyzing these bioactive compounds, whereby large-scale production could become a reality, paving the way for potential parsley-based, locally manufactured medicines in the future.
- Biodegradable Plastic from Brown Algae:
Addressing the global concern of plastic pollution, this research focused on developing biodegradable plastics from brown algae. Bioplastics made from renewable natural resources like algae offer several advantages over traditional plastics derived from petroleum/fossil fuels, the most notable of which is that they are biodegradable and have minimal impact on the environment. The researches extracted sodium alginate from Sargassum seaweed and incorporated plasticizers and starch to improve the film’s properties, producing functional, intact plastics with varying density, and even a bleached variety that is entirely transparent. The initial results show promise, suggesting that bioplastics derived from brown algae have the potential to become a viable solution for much more than just the packaging industry.
- Eliminating Water Wastage in Asmara Brewery:
The study aimed to reduce water consumption at Asmara Brewery by identifying and addressing sources of water waste. Researchers found that a significant portion of water was being wasted in operations like chase water (clean water used to push finished beer into storage tanks), bottle washer (wastewater generated during the cleaning of returnable bottles), and filling (foamy beer overflow from the filling machine). The findings suggested two promising wastewater treatment methods: Alum treatment, which achieved a 92.2% water recovery rate from bottle washing wastewater, and MO (Moringa Oleifera) seed coagulation, which demonstrated an 86.6% water recovery rate from mashing tun wastewater and a 97.2% removal rate of influent turbidity. More specifically, MO seed powder demonstrated promising results in removing pollutants like COD (Chemical Oxygen Demand) and BOD5 (Biochemical Oxygen Demand), and turbidity. While these findings showcase the potential for significant water conservation, further investigation is required to address large-scale implementation. Building a dedicated wastewater treatment plant calls for substantial space allocation, and utilizing MO seeds as a natural coagulant necessitates a robust agricultural sector to cultivate the required quantities.
This research makes way for an alternative path for Asmara Brewery to incorporate sustainable practices. Implementing effective wastewater treatment and reuse strategies can significantly reduce reliance on freshwater resources, contributing to a more environmentally responsible future for the brewery.
- Increasing Lime Production in Eritrea:
This study tackles a crucial need for Eritrea’s growing industries which is an increased production of quicklime (CaO), and focuses on the production of quicklime from different regions in Eritrea through calcination method and optimizing the process parameters such as temperature, particle size, and reaction time.
Currently, Eritrea’s lime production is limited, primarily serving the construction sector. As the mining activity in the country expands, however, with large mining companies like Bisha and Zara, the local demand for lime is bigger than ever before. The objective of this research is to identify local source sites of lime, develop methods to produce high-quality lime in a controlled laboratory environment, to design efficient lime production facilities based on the optimized process, and to minimize energy consumption during the lime production process using advanced software tools like EXCEL®, POLYMATH®, and Generic Algorithm (GA).
The researchers conducted a total of 36 experiments to find the optimal setting for energy-efficient lime production. The findings underline the importance of identifying new local sources of limestone for production, designing efficient lime production plants based on the optimized process, and reducing reliance on imported lime. This could not only address the domestic demand but also position Eritrea as a potential lime exporter, boosting its industrial growth.
- Energy Recovery from Gedem Cement Emissions:
This research investigates energy-saving opportunities in Eritrea’s cement industry, focusing on the Gedem Cement Factory. Cement production is notoriously energy-intensive, requiring significant capital investment. The study explores potential methods to reduce energy consumption at Gedem, validate these models through testing, and assess the economic and environmental benefits of the proposed solutions.
Cement production involves several energy-intensive steps, including preparing raw materials, pulverizing coal, clinker calcination (burning), and grinding the final product. Traditionally, cement plants utilize rotary kilns with multi-stage cyclone preheaters. Modern plants typically consume 3 – 3.5 GJ/ton of electrical energy for clinker production. Dry process cement plants, like Gedem, can recover up to 40% of their total heat input from waste gas exiting the preheater and clinker cooler.
The research proposes implementing a hybrid waste heat recovery (WHR) system at Gedem. This system would combine a Waste Heat Recovery (WHR) unit with an Organic Rankine Cycle (ORC) unit using R134a as the working fluid. This system has the potential to recover 2.745 MW of energy, generating approximately 19.764 GWh of electricity per year (assuming 300 operational days).
Preliminary economic analysis suggests potential annual savings of up to 3.294 million USD based on Eritrean electricity tariffs and the proposed system’s generation capacity. Additionally, the WHR system would contribute to a reduction of 5.027 million liters of oil consumption and mitigate CO2 emissions by an estimated 14,880 tons per year. This research offers a promising approach for improving energy sufficiency and environmental sustainability within Eritrea’s cement industry. The proposed hybrid WHR system, if implemented, could significantly benefit Gedem Cement Factory by reducing operational costs and environmental impact.
- Production of Biochar Fertilizers from Mangrove and Prosopis juliflora:
This research explores a promising alternative to conventional fertilizers for Eritrean farmers, who rely heavily on chemical options like DAP and Urea, whose long-term use can harm the environment through ground water contamination and soil degradation. This study proposes biochar, a charcoal-like substance produced from organic materials like Prosopis juliflora (a fast-growing tree) and mangrove trimmings, as a sustainable and effective organic fertilizer.
The researchers produced biochar using a process called pyrolysis, which involves heating plant material at high temperatures (350⁰C) in an oxygen-limited environment. Biochar was then added to the soil, either alone or with existing organic fertilizers, to assess its impact on plant growth. Salad plants were the test crops used to compare the effectiveness of biochar fertilizer with conventional options and a control group. The P. juliflora biochar showed the most promising results, increasing both the weight and root length of the salad plants, whereas the mangrove biochar, though effective in increasing plant weight, had a varied impact on root length. The combination of biochar from P. juliflora and poultry manure achieved results comparable to DAP fertilizers in terms of plant weight and root growth. These findings suggest that biochar holds immense potential as a sustainable and effective fertilizer for Eritrean agriculture.
Biochar is believed to enhance water retention, nutrient storage capacity, and overall soil health. Unlike chemical fertilizers, biochar may also help reduce soil pollution and promote carbon sequestration. Further research can optimize production methods and explore its impact on various crops, leading to a greener and more productive agricultural future.
Written by Sona Berhane