capstone abstracts.docx

7/30/2019 capstone abstracts.docx

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ABSTRACT-Luke Zvinei

The wide range of achievable properties of polyurethane products makes it an indispensable

component in the construction, furniture and bedding, footwear, packaging and transport,

apparel and consumer products and automotive industrial sectors. However, since

polyurethane manufacturing rely significantly on fossil fuels and petroleum oil as the

feedstock for its major components, the depletion of the world oil pool, rising prices of

petroleum crude oil and increased environmental concerns are pressurizing research into bio-

based polyurethane. This project focuses on the design of a 2 tonnes per day bio-based

polyurethane plant. Comprehensive examination of technological advances and vegetable oil

modification methods was done and the production process involving oil hydrolysis using

rigosa lipase at 55% followed by polymerization reaction was designed. From series of

experiments conducted through titration method, acid index and hydroxyl number of polyol

were found to be 211 and 2.5mgNaOH/g respectively which agreed with those found from

spectrometric polyol characterization method. For reactor design, chemical kinetics of the

reactions was also titrimetrically determined and results were 76.8% polyol yield, chemical

conversion of 80%, rate constant of 4.610-4L/mol.min and order of reaction 2 was within the

literature range of 1 to 2. Aspects of temperature, flow control and HAZOP analysis of the

polymerization batch reactor and shell and tube heat exchanger were also covered. Economicanalysis of the project gave a payback period of 3yrs, return of investment of 34% and

internal rate of return of 23.4%. Hence the researcher recommends the setting up of this

polyurethane plant.

Key words: Polyurethane, hydrolysis, titration, acid index, hydroxyl number, polymerization,

conversion.


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Abstract- Tendai Gweshe

Polychem Private Limited runs a laundry powder detergent plant which has a capacity of

300kg per day. The process uses the hot air blower method for slurry drying which is now

obsolete and has more draw backs which impact negatively on product quality, workers

health and production efficiency. The current and the anticipated future demand of washing

powder in the next 4 years stands at 700 and 1500kg per day respectively which is far too

high than the current plant capacity. Hence the project focuses on the design of a 1.5 tonnes

per day semi-batch washing powder processing plant to upgrade and replace the old process

with a new technologically advanced process. Experiments were done to determine the slurry

drying temperature, atomization pressure, conversion and thermal efficiency of the spray

dryer which led to the design of a combined spray dryer and agglomeration process. A

detailed process and equipment design of the spray dryer and the air-to-air waste heat

recuparator was carried out. An economic analysis was done to assess the economic

feasibility of the project. It was concluded that it is possible to design an economically viableand environmentally friendly 1.5 tonnes per day semi-batch washing powder processing

plant. The project has a payback period of 3.3 years and a return on investment of 36.5%

which are acceptable financial indicators. For future developments, it is recommended that a

full automation of the process and an employment of Computational Fluid Dynamics (CFD)

softwares should be employed in the spray dryer experimental analysis so as to come up with

correct results of the slurry drying phases thus maximizing the production cycle time all year

round.


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ABSTRACT-Penelope Malunga

An experimental approach was taken in the design of a process for the dry beneficiation of

gold ore which can be used as an alternative process to the cyanidation process. Experimentalwork was undertaken to determine the moisture content, recovery and enrichment ratio of

gold ore. Maximum recovery was found to be 90% and maximum enrichment ratio was 1.81

for the oxide ore sample. The vertical turbo dryer and fluidized bed separator was designed to

help achieve the desired gold concentrate and the control of this equipment was automated

using micro-controllers. The dry beneficiation process gave the company a net present worth

of US$26 million with a payback of 3.2 years and a breakeven at 9 500 units (ounces). It is

further recommended that optimization approaches be in-cooperated in further study and aprototype be developed.


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ABSTRACT-Lavinia Chikomo

Sugar manufacturing processes produce sugar and by-products which are bagasse and

molasses. Approximately 60% of the produced bagasse is being used for the generation of

heat and 40% of bagasse is left unused. This bagasse is a valuable raw material in furfural

production which is currently being imported into the country. The project focuses on the

local production of 2 tonnes per day of furfural which bring financial benefits to the nation

through reduction of furfural products importation and thereby improving the local chemical

industry. Experiments were done to determine the mineral acid catalyst for the cyclo-

dehydration, reacting temperature and pressure, order of reaction and conversion factor of the

cyclo dehydration reaction of bagasse to furfural. The results obtained led to the design of a

cyclo-dehydration batch reactor and distillation column. Process instrumentation and control

diagrams (PID) and hazard operability studies (HAZOP) were done on the designed

equipment to ensure safe operations. A detailed economic analysis was done to assess the

economic feasibility of the project. The project has a payback period of 2.5 years and a return

on investment of 31.9% which are acceptable financial indicators. It was concluded that it is

possible to design an economically viable and environmentally friendly furfural

manufacturing plant. Further optimization of the process to incorporate energy integration

techniques in the plant to ensure efficient and more economical energy use by consuming the

bagasse pulp residue produced as a source of fuel to the boilers is recommended.


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Abstract-Abraham Botoro

The project intends to carter for the high glucose demand in the county since there is a

growing population of starch derivatives industry, present demand which is estimated at 1000

tonnes per annum. This capstone project has designed a plant that produces 3 tonnes of

glucose per day from cassava. The project has an impact in the value addition of the cassava

crop which has an annual output of 50 000 tonnes country wide. Acid and Enzyme

Hydrolysis experiments were carried out to determine maximum conversion and to determine

the one with the least cost of production. Concentration of 1.5g/L of alpha amylase enzyme

hydrolyzed 100cm3 of starch in 7 minutes. The quantitative information obtained from the

experiments showed the conversion of starch to glucose to be 97% and the rate of reaction

showed an in increase with increase in enzyme concentration. The obtained results were

scaled up to design the bioreactor. Environmental impact assessment was carried out for the

plant from inception, construction and operation and was found to be safe. The total capital

investment was calculated to be $3.2million. A return on investment of 34 % and a payback

period of 3.2 years showed high returns. It was concluded that it is possible to design the

plant. Zimbabwe being an agro-based economy would benefit immensely from beneficiation

of cassava raw materials.


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ABSTRACT- Ngoni Masukusa

Jatropha cake is a highly nutritious and economic protein source for animals. At Finealt

Engineering Company 450tonnes of the press milled cake is produced per day and 380tonnes

goes into the production of organic fertilizers and biogas and 70tonnes is left unutilized at the

company warehouse. It is in this light that this project was carried out to design a

53tonnes/day jatropha cake detoxifying process to produce animal stock feed using an

economical and is environmentally friendly process.

Jatropha cake was detoxified from the experiments using solvents methanol and NaOCL of

mass 2.769tonnes and 1.5275tonnes respectively, which extracted the phorbol esters (toxins)

by applying chemical and process system engineering principles and techniques in thisprocess. The level of phorbol esters which must be 11ppm in accordance to ISO standards

were reduced to 6ppm from 18ppm making the jatropha cake edible and suitable to be used as

animal stock feed

A 2hour batch system was designed in which 13tonnes /batch of cake is first milled to a

particle size of 10mm the mixed in a reactor with a10tonnes of petroleum ether and 20tonnes

water then extracted and lastly dried by a rotary drier to remain with cake of 4% moisture. A

PLC control system was used for the overall process control and instrumentation. A total of

$216 300, 00 was calculated as the total capital to be invested in this project with a rate of

return of 18.85%( 5,3yrs) and a break even after producing 7.6units (130.72tonnes).In

conclusion the project was technically and economically viable and also the raffinatewas

recommended to be used to produce pesticides and an honest look to be made on the risks to

human health associated with all means of interaction with the seed cake.


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ABSTRACT-Bernard Ganzwa

Several thousand tonnes of water treatment sludge are produced annually at Longlands water

treatment plant. The management of this sludge has been of increasing concern due to the

detrimental impacts caused by the sludge to the environment..The Longlands water treatment plant

has a production capacity of 42Mega litres a day. 7% (2.94Mega litres) of the raw water received at

the plant per day is lost during downstream processes (backwashing and de-sludge process). From

experimental work carried out at The Institute of Mining Research Zimbabwe, it was ascertained that

0.34% of the lost water are total solids such that 1069.45Mega litres of water are lost per annum

and 3648.54 tonnes of dry solids are generated per annum. The total solids in the sludge contain

28.6% aluminium (aluminium hydroxide and aluminium oxide), 88% of the aluminium is recoverable

by leaching using sulphuric acid. This project is aimed at reclaiming and reusing aluminium sulphate.

The proposed aluminium sulphate reclamation plant has a maximum production capacity of

10751kg/day of aluminium coagulant which is equivalent to 10665.75Liters/day. Operating under

optimal conditions, the plant has three production shifts scheduled for the day. Mechanical design of

the designed plant is based on the batch capacity, detailed designs of the sludge dewater unit with a

capacity 700m3

and leaching reactor with a capacity of 5.4m3

is highlighted in this project. The

aluminium reclamation plant is about 80% automated incorporating 2 mode of control algorithm,

PID control and cascade control. The aluminium reclamation plant is to be situated next to the

Longlands water treatment plant. A preliminary environmental impact assessment of the plant

highlighted that the potential negative impacts can be easily mitigated. The economic feasibility of

aluminium coagulant recovery was done using the process design parameters. The plant has a

payback period of 4.2 years, rate of return 23.97% and Internal rate of return of 18%. An OPEX

reduction of 36% was obtained using the acid leaching and ion exchange processes which shows a

quite significant economic viability.


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ABSTRACT- Stephany Teuro

The purpose of this project was to come up with an alternative process for the production of

phosphoric acid which does not produce gypsum as biproduct. The project was also done to

reduce the production time of mono-calcium phosphate from four days to at most two days.

The raw materials used were phosphate rock, sodium sulphate and sulphuric acid. The project

was carried out as case study of Varitech Industries situated in Ruwa Industrial park.

Laboratory experiments were carried out at using different conditions. The temperatures used

were 100 0 C, 1500 C and room temperature. All the experiments were carried out at

atmospheric pressure. The Calcining temperature was 12000 C. The concentration of sodium

carbonate used was 2.72 moles per litre. The purpose was to determine the effect of changing

temperature on the rate of reaction and yield. The experiments showed that an increase in

temperature will result in the increase in the rate of reaction but there is a decrease in the

amount of sodium phosphate produced. The major process equipment were also designed.

On completion of the project it was proved that it is possible to produce phosphoric acid

using this process without having gypsum as the bi-product. The economic analysis carried

out showed that the project is a viable project with a payback period of three years and return

on investment of 22.8%.


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