Department of Chemical and Process Systems Engineering
Permanent URI for this collectionhttps://cris.hit.ac.zw/handle/123456789/8
Browse
47 results
Search Results
Item Mould and Die Design(HIT, 2025-11) HITItem Heavy Metal Ion Effluent Discharge Containment Using Magnesium Oxide (MgO) Nanoparticles(Materials Today: Proceedings., 2017-12) Madzokere, Tatenda C.; Karthigeyan, AIn this study, the adsorption of copper (II) ions using nano-magnesium oxide was investigated. Mesoporous MgO nanoparticles were prepared by a relatively simple and economic combustion synthesis technique. The metal oxide nanoparticles were studied by powder X-ray Diffraction (XRD) for structural analysis, Field Emission Scanning Electronic Microscopy (FESEM) for surface morphology, Energy-dispersive X-ray spectroscopy (EDS) for elemental analysis and Fourier Transform Infrared (FTIR) spectroscopy for chemical structure. The crystalline size obtained from Debye-Scherrer’s formula was in the range of 12–17 nm. The FESEM result revealed that the nano-MgO powder is porous in nature and highly agglomerated, whilst EDS confirmed the presence of elemental Mg and O in the highly fine white powder which was obtained after annealing the final precursor reaction mixture derived from magnesium nitrate and amino acetic acid at 500 °C for 2 hours. X-Ray Fluorescence Spectrometry (XRF) was utilized for analysing the adsorption properties of nano-MgO powder. It was observed that 0.20 grams of nano-MgO could remove 96 % of heavy metal ions (Cu2+) from a standard (10 ppm) copper (II) chloride solution compared with commercial grade MgO which exhibits a removal capacity of 15%. This study has potential applications in the treatment of effluent containing copper ions at the level of discharge to the environment in industrial operations such as mining, chemical manufacture and electroplating.Item Treatment of Piggery Wastewater using an Acti-zyme (Biocatalyst) and Paper mill Biochar Compound Co-capturing Biogas(5 th Anniversary of ANSOLE (2011-2016): International Conference on Renewable Energy (INCORE2016), 2016-02-03) Manyuchi, Musaida Mercy; Guvavaa, Grace N.; Ikhu-Omoregbe, Daniel I. O; Oyekola, Oluwaseun O.The world is facing formidable challenges in meeting rising demands of clean water as the available supplies are depleting due to extended droughts, population growth, more stringent health based regulations and competing demands from a variety of users. At the same time, wastewater treatment plants are using energy from the national grid rather than generating their own energy. Piggery farms and paper mills make use of a lot of water and thus contribute towards water shortage. The piggery farms produce a significant amount of wastewater which water can be effectively treated via anaerobic routes to harness biogas. On the other hand, paper mills are generate excessive amounts of sludge during paper making process. Secondary treatment of wastewater can therefore be used to make sludge based activated biochar which can be used in wastewater treatment. This work assessed the feasibility of using a compound from activated carbon from paper mill sludge (PMS) and Acti-zyme (a digestion bio-catalyst) to treat piggery wastewater anaerobically and co-capturing the biogas produced for energy usage. A piggery wastewater treatment plant generating 6000 m3 /day of wastewater was considered and the change in the wastewater physicochemical properties was determined using standard methods. The amount of biogas produced was determined using a water displacement method for retention periods of 30 days at 37 °C. The use of Acti-zyme and PMS biochar compound at 50 g/m3 reduced the piggery wastewater contaminants properties such as total solids, colour, pH and BOD5 by >70%. The treated effluent met the set standards for effluent water disposal. Biogas was produced at a rate of 2.3 m3 /m3 .day with a bio-methane composition of about 78%Item Techno-economic feasibility of using sorghum brewers spent grain to generate one megawatt of electricity using direct combustion technology(Conference: 47th Ghana Institution of Engineers (GhIE) Annual Conference,, 2016-03-29) Manyuchi, M.M; Frank, RThe paper presents a study that was conducted to assess the techno-economic feasibility of a sorghum brewers spent grain (BSG) fired boiler unit to generate 1 megawatt of electricity for a certain brewery company. The brewery company is currently generating 24 tons per day of sorghum brewers spent grain biomass waste which was used as a source of boiler fuel for this work. After a full proximate analysis the sorghum brewers spent grain had an average heating value of 12.6 MJ/kg whilst coal had 19.9 MJ/kg indicating that it is feasible to generate electricity using sorghum brewers spent grain as a source of fuel, and that sorghum brewers spent grains can be used as an alternative to coal. A process for conversion of the BSG to electricity was proposed for a biomass boiler unit consuming 1100 kg/hr BSG, operating at 86% efficiency, maximum pressure of 9 bar and steam output of 1689kg/hr was designed to supply a one megawatt turbine generator. Pressure, temperature and flow control mechanisms were assessed as a safety consideration. An economic analysis was done with a total investment cost of USD$ 3.4 million, a payback period of 3.7 years, and a return on investment of 27.4%. BSG provide an alternative source of electricity for the brewery industryItem TECHNO-ECONOMIC ASSESSMENT FOR BIOGAS GENERATION FOR ENERGY USAGE FROM MUNICIPAL SEWAGE SLUDGE USING ACTI-ZYME AS DIGESTION CATALYST(Chemical Science International, 2016-01-21) Manyuchi, M.M; Ikhu-Omoregbe, D.I.O; Oyekola, O. O.; Gwarimbo, WA sewage plant with a capacity of 19 600 m3 /day was considered for techno-economic assessment, with an operating efficiency of 60% and a life span of 20 years. $5.125/day of Acti-zyme were required for production of 12 769.69 kg/day for biogas costing $1.50/kg and 672.08 kg/day of bio-solids costing $16.00/50kg. Capital budgeting techniques were then used for techno-economic assessment of sewage treatment recovering biogas and bio-solids. A net benefit of $5 656 363.92 per annum for using the Acti-zyme technology in sewage digestion was forecasted, whilst a net energy of 1 387.33 KWh was set to be produced. An investment of $22 199 501.40 was required for kick-starting the project. A positive net present value of $1 186 239.23 was realized with an internal rate of return of 17.6% and a payback period of 5.9 years. For breakeven to be realised, only 183 059.16 KWh must be produced. The techno-economic assessment indicated it is viable to treat sewage using Acti-zyme co-harnessing biogas and bio-solids as valued added products to an extent of making 0.04% to the Zimbabwe gross domestic product.Item Sewage Plants' Potential to Produce Biogas for Electricity Generation-Case Study of the Three Zimbabwe Municipalities.(2016-09-02) Manyuchi, Mercy , Govha, Joseph , Tichapondwa, Shepherd , Oyekola, Oluwaseun & Ikhu-Omoregbe, DanieTreatment of municipal sewage sludge is a problem in Zimbabwe. However, if the appropriate waste to energy technologies are applied, sewage plants can generate their own electricity thus minimizing municipalities’ reliance on the already strained national grid. An experimental study was therefore conducted on the Chitungwiza, Firle and Crowborough sewage plants, assessing the potential to harness biogas for electricity generation. These plants have sewage treatment capacities of 19.6 ML/day, 140 ML/day and 54 ML/day, respectively. Plant tours and inspections of the plants were conducted and an understanding of the plant designs as well as the current process flow was attained. Particular emphasis was placed on establishing the availability and state of infrastructure available for the production, handling and storage of biogas. All three plants have bio-digesters on site, however, the Chitungwiza digesters are open at the top thus releasing gas to the atmosphere. Firle and Crowborough plants are equipped with the basic infrastructure for biogas generation and storage; however, major refurbishments are required. Samples of sewage sludge were collected from the plants and placed under conditions that mimic a typical digester, the resultant biogas was analysed. The biogas was predominantly composed of methane (53-65%), CO2 (22-27%), trace gases such as H2S, N2 and H2 accounted for the balance. Experimental results revealed that the use of 50 g/m3 Actizyme as a bio-catalyst increases the quantity of methane produced to 72-78%. Based on the experimental results and the design capacities of the plants, the estimated power generation potential was 0.57-1.20 MW, 4.2-8.1 MW and 1.53-4.56 MW for the Chitungwiza, Firle and Crowborough, respectively. These capacities vary depending on whether it is the wet or dry season. An economic assessment indicated the viability of harnessing biogas from the three plants especially after incorporating Acti-zyme as the digestion catalyst to actively increase the electricity generated.Item Preparation and Characterization of Polymer-Grafted Montmorillonite-Lignocellulose Nanocomposites by In Situ Intercalative Polymerization(Journal of Applied Chemistry, 2016-07-11) Bunhu, Tavengwa; Chaukura, Nhamo; Tichagwa, LilianLignocellulose-clay nanocomposites were synthesized using an in situ intercalative polymerization method at 60∘ C and a pressure of 1 atm. The ratio of the montmorillonite clay to the lignocellulose ranged from 1 : 9 to 1 : 1 (MMT clay to lignocelluloses, wt%). The adsorbent materials were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), and X-ray powder diffraction (XRD). FTIR results showed that the polymers were covalently attached to the nanoclay and the lignocellulose in the nanocomposites. Both TEM and XRD analysis showed that the morphology of the materials ranged from phase-separated to intercalated nanocomposite adsorbents. Improved thermal stability, attributable to the presence of nanoclay, was observed for all the nanocomposites. The nanocomposite materials prepared can potentially be used as adsorbents for the removal of pollutants in water treatment and purification.Item Design of a pyrolysis reactor for biochar production for ‘motocharcoal’ briquettes(5 th Anniversary of ANSOLE (2011-2016): International Conference on Renewable Energy, 2016-02-03) Kanyenga, P.; Manyuchi, M.MZimbabwe is an agro-based country and as a result produces a lot of agro-waste ca. 70 000 tons per year. This waste occurs primarily in the form of waste cornstover, bagasse and sawdust which are currently not being utilized. There is potential for conversion of this agriculture waste to charcoal briquettes using the slow pyrolysis technology which increases the waste materials’ heating value. This paper presents a design for a pyrolysis reactor that can be used for conversion of agricultural waste to biochar which can then be used to make, Motocharcoal which is a trade name for the densified charcoal briquettes that are currently being made in Zimbabwe. It is an eco-fuel that can be used for heating and cooking purposes with a heating value of 22.5 MJ/kg. The pyrolysis reactor design was carried out based on an operating capacity of 12 tons/hr for an 8 hour working period based on the availability of the raw material which was mainly cornstover with a density of 200 kg/m3 . Pyrolysis took place under anaerobic conditions to enhance carbonisation. This was done at a temperature of 300 °C and a retention time of 3 hours to increase the calorific value of the biochar before briquetting. A conversion rate of 70% from agro-waste to biochar was achieved. The pyrolysis reactor will be constructed using stainless steel. Temperature and pressure were identified as the critical process parameters that must be controlled as these affect the quality of the biochar which in turn affects the briquettes quality. The pyrolysis reactor volume was 15.3 m3 with atmospheric pressure as the working pressure and a design pressure of 14.9 MPa. Fiberglass will be used as the insulation material to minimise heat losses and water used as the cooling agent. The designed pyrolysis reactor will ensure optimal conversion of the agro-waste to biochar for high quality briquettesItem Biosorbents for the removal of synthetic organics and emerging pollutants: Opportunities and challenges for developing countries(Environmental Development, 2016-05-23) Chaukura, Nhamo; Gwenzi, Willis; Tavengwa, Nikita; Manyuchi, Musaida MercyContamination of aquatic systems by synthetic organic contaminants and emerging pollutants poses significant public and environmental health risks in developing countries. These contaminants mainly originate from textile, agrochemical, and pharmaceutical industries. The removal of such contaminants is problematic in developing countries because advanced water treatment methods are still lacking in developing countries due to their high costs. The application of biosorption for removal of organic contaminants in developing countries is attractive for three reasons; (1) large quantities of biomaterials for use as biosorbents are readily available; (2) lack of advanced water and wastewater treatment systems for removal of organic contaminants; and (3) the technology is relatively cheap compared to advanced methods (e.g. membrane filtration) often used in developed countries. Overall, this has the potential to remove organic contaminants from aqueous systems while simultaneously reducing the public health and environmental impacts associated with the disposal of such biowastes. However, large-scale application of biosorption faces potential challenges including lack of funding, poor mechanical properties of biosorbants, complex adsorption mechanisms involved, and poor regeneration capacity. In addition, spent biosorbents present an environmental risk and their disposal is problematic due to the potential of contaminating surface and ground water. Possible disposal methods for spent biosorbent include use as a filler in road surfacing, as a soil amendment, and in phytoremediation cells where the organics are absorbed and broken down by plants. Overall, biosorption is a potentially viable alternative, but further research on its ability to remove pollutants from multi-component systems, its regeneration capacity, and plant design parameters is required before the benefits of the technology are realised in developing countries.Item Biogas Production from Saw dust using Acti-zyme as Digestion Catalyst and its Upgrading to Bio methane using Chemical Absorption(World Energy Council Congress, 2016-01-01) Manyuchi, Musaida Mercy; Bobo, Arthur. E.; Ikhu-Omoregbe, Daniel I. O; Oyekola, Oluwaseun O.Zimbabwe has one of the largest deposits of timber in Southern Africa (about 500 000 tons per annum) such that most entrepreneurs venture into timber processing. The venture results in generation of a lot of sawdust dumps that are of no economic use if they are left lying around. There is 10000 metric tons that go to waste each year which when bio-converted can result in biogas. This paper therefore presents the potential for biogas production from saw dust bio-catalysed by Acti-zyme a biocatalyst to enhance the digestion hence biogas yield. This paper presents the bio-catalysed digestion of 4000 metric tons of saw dust per year to produce biogas using Acti-zyme. The generated biogas is then upgraded using chemical absorption for removal of carbon dioxide so as to increase the bio methane energy efficiency. Biogas produced was approximately 24 m 3 per day and was upgraded to 97% from 72% bio-methane composition per day using chemical scrubbing technique in an absorption column. The absorption column design considerations are also presented as well as its process control and the hazard analysis. These are essential in the optimal upgrading of the biogas. Purified bio methane has a higher calorific value of 99 % relative to the 77 % of raw biogas. An economic analysis showed that a 2 year payback period with a return on investment of 48% and break even sales at $331 580.00 with the upgraded bio methane being sold at $2.50/kg. The conversion and upgrading of biogas produced by anaerobic digestion using Acti-zyme is technologically, economically and environmentally feasible.