Biodiesel Processing

Chemical Engineering

Problem Statement

When crushed and processed, the nuts of the shea tree yield a vegetable fat known as shea butter. It has long been a common ingredient in local foods and soap, but its qualities also make it a valuable export, for use in the manufacture of chocolate and cosmetics. The tree grows throughout the semi-arid Sahel region of West Africa, but the largest concentration is in Burkina Faso, where exports of shea butter and unprocessed shea kernels brought in $7 million US in 2000, making it the country's third most important export, after cotton and livestock.

The harvesting and processing of shea is primarily an activity of rural women, between 300,000 and 400,000 in Burkina alone. So its earnings directly benefit some of the poorest villagers, in a country classified as one of the poorest in the world.

Women work in groups to process the shea nuts using both human- and diesel-powered equipment. Diesel, however, can be very expensive in rural areas that are not accessible by paved road due to the high costs of transportation.

A proposed solution to the problem of high diesel costs is to use the shea nut processing equipment to process oil from the seeds of a local shrub called Jatropha. The oil can be processed into a quality biodiesel that can be used in almost any diesel engine. This biofuel can then be used by the women’s groups as a cheaper alternative to diesel for processing the highly profitable shea butter.

Project Scope

Jatropha based biofuels can be produced at a large, industrial scale, as well as at a smaller, community level scale. In terms of contributing to the improvement of living standards for the rural poor, community level operations can have significant impact by creating rural business and employment opportunities.

You have been hired by Engineers Without Borders to design a small-scale biodiesel processor capable of producing approximately 1,000 L per week.

Using the base catalysed transesterification process, come up with a simple hand-sketch indicating equipment and layout. You may choose specific raw materials (oil, alcohol and base type) based on your own rationale. There are a number of resources about processor design available on the Internet, and these will be useful in getting you started. Use your imagination, too!

The following points should be addressed in the design, including:

• The volumes and sizes of the tanks and tubing (if applicable). Indicate the overall footprint required for the processor.

• The materials choices for the processor components.

• Storage media for raw materials, biodiesel and by-products.

• Other than raw materials, what inputs will the processor require for operation (i.e. power, compressed air, water and ventilation).

• Health and safety considerations.

• Cost: while you are not required to cost specific components, in any real design project, cost will always be a major factor. Give some thought to ways of keeping both the construction and operational costs of your processor low, and try to incorporate this into the design.

Provide a report to Engineers Without Borders outlining your approach to the problem, your conclusions, and any further recommendations you feel should be considered.

You should organize your report into the following sections:

• Executive Summary

• Problem Identification (include Constraints and Criteria)

• Proposed Solution and Justification

• Conclusion and Recommendations

• Appendices (include Calculations)

• References

• Technical sketches or drawings

Design of a Rainwater Harvesting Unit

Civil Engineering

Problem Statement

In the Nilgiris District of Southern India, a majority of the rural population does not have access to an adequate supply of water for domestic use. With the groundwater resources showing signs of depletion, the Government of Tamil Nadu has made it mandatory to install rooftop rainwater harvesting (RWH) units on all households within the State. Unfortunately, most rural villages in the region have limited ability to financially support this initiative. Since the largest cost component of the rainwater harvesting structure is the storage unit, careful planning must go into sizing RWH units to ensure the people receive an adequate supply of water, at the lowest possible price.

You are working with the Rural Development Organization in the Nilgiris District to improve access to an adequate supply of water in rural areas. Your organization intends to work on a pilot project with the village of Muvukall to develop the design requirements for implementing RWH structures on all household rooftops.

Gutters collect water from roof

In your design choices, consider the following details:

• Water Demand of the Rural Village: A discussion with the people of Mavukall indicates that each household requires 240 koodahm’s of water per month. Koodahms are the water jugs used around the house, and generally hold 12 litres of water. The village of Mavukall has a total of 42 households that have the same monthly water requirements.

• Rooftop Area: There are two typical house setups within Mavukall village. A smaller number of more affluent villagers have larger houses with galvanized iron sheets, whereas the majority of people live in smaller houses. There are no houses in the village with gutters. Each type of rooftop material has a different runoff coefficient that reflects how much water ends up in the storage tank as opposed to being lost due to spillage or leakage. The rooftop details for Mavukall village are in Table 1.

Table 1: Rooftop details for Mavukall village

• Precipitation Data: The Nilgiris District has great fluctuations in precipitation throughout the year. A dry season from January to March provides an average precipitation of 14 mm/month. Subsequently, there are two monsoon periods that bring heavy rains to the district. The south-west monsoon between June and September and the north-east monsoon from October to December bring an average of 140 mm/month. The monthly precipitation data for twenty years are provided in Table 2.

Table 2: Twenty years of monthly precipitation data for Mavukall

• Cost: Cost is a major factor impacting the feasibility of implementing rooftop RWH units in Mavukall village. The Nilgiris District has recently conducted an assessment to determine the overall costs of installing RWH units (Table 3).

Table 3: Cost components of RWH unit

• Additional information

  • The village is located on steep land in a mountainous region of the district.

  • Most of the land is degraded forests with sections of the slopes converted to agricultural land with poor soil conservation measures.

  • The average soil depth in the vicinity of the village is 20 metres with clayey soils.

  • An industrial plant upstream of the village on a major river dumps toxic chemicals directly into the river.

Project Scope

You have been hired as an engineer to do the following:

• Develop the storage requirements necessary to provide the village of Mavukall with their ideal demand 90% of the time.

• Develop the total costs for constructing rooftop RWH on every house in Mavukall village to determine if it is an economically feasible source.

Provide a report to Engineers Without Borders outlining your approach to the problem, your conclusions, and any further recommendations you feel should be considered.

You should organize your report into the following sections:

• Executive Summary

• Problem Identification (include Constraints and Criteria)

• Proposed Solution and Justification

• Conclusion and Recommendations

• Appendices (include Calculations)

• References

• Technical sketches or drawings

Design of a Village Battery Charger

Electrical Engineering

Problem Statement

In rural Ghana, approximately 80% of households lack access to electricity. Even those lucky enough to tap into the main grid suffer from frequent and extended rolling blackouts, making the reliable supply of power a development priority. Energy is a key component to meet many of the Millennium Development Goals, such as improved health care, education, and food security. With electricity, children are able to study at night, medical procedures (such as delivering babies) can be done much more safely and effectively, and refrigerators can be used to store vaccinations and food that would otherwise rot.

You are an Electrical Engineer working for an organization in Ghana that aims to provide a reliable and affordable source of energy for a village that is not likely to see the electricity grid for at least 10 years. Your organization would like to create a market for 12V DC batteries in the village to be used for powering lights, refrigerators (including a vaccine refrigerator for the local clinic), and entertainment such as stereos and televisions for football games.

In the village, there is an entrepreneur with an existing 8hp diesel engine coupled to a corn mill on one side and a cassava grater on the other (Figures 1 and 2). The machines can only be run one at a time using a belt drive. All of the equipment is cemented into the floor and often breaks down because it was not aligned properly during initial installation.

Figure 1: Engine and Cassava Grater

Figure 2: Engine and Corn Mill

In your design choices, consider the following requirements:

• Technical Considerations: New batteries cannot be charged past 12V (or they may explode!) and have a capacity of 150Ah. Your market survey has shown that you expect a minimum of 5 batteries to be dropped off for charging a day.

• Charging Dead Batteries: Many villagers already use disposed car batteries to power black and white televisions, and will be a primary target market for your battery charger. They have to replace the electrolyte with each charging to get them to last approximately one week. When charged to only 12V, these batteries will only last 10 minutes so they need to be charged until the electrolyte boils for 10 minutes (roughly around 14.5V). Since a football game lasts longer than 10 minutes, you will have very angry customers if they pay to have their batteries charged and they don’t even make it to half time! Expect a mix of new and old batteries to be dropped off for charging at any given time.

• Cost: Cost is a major factor impacting accessibility of the technology to rural householders. Your organization has recently conducted an assessment to determine how much each household would be willing to pay for battery charging. According to this research, a customer would not be willing to pay more than $1 to have a battery charged, and would expect it to last at least one week.

Project Scope

In a town about an hour away there is an automotive shop that also charges new batteries for $1.50. The entrepreneur would like to be able to charge both new and dead batteries simultaneously. Your job is to design a simple electrical circuit that enables the user to know when a 12V battery is fully charged so that you can remove them from the charging system and allow the dead batteries to continue to charge.

In your design, you must decide whether you would like to charge the batteries in series or parallel. Note that with the parallel configuration you will need to install a resistor after the alternator in order to decrease the voltage to 12V for the batteries. If you choose the parallel configuration you will need to calculate the value of the resistor needed to have a 12V drop across the batteries.

Provide a report to Engineers Without Borders outlining your approach to the problem, your conclusions, and any further recommendations you feel should be considered.

You should organize your report into the following sections:

• Executive Summary

• Problem Identification (include Constraints and Criteria)

• Proposed Solution and Justification

• Conclusion and Recommendations

• Appendices (include Calculations)

• References

• Technical sketches or drawings

Design of a Solar Water Distiller

Engineering Physics

Problem Statement

The Aral Sea is bounded by Kazakhstan on the north and Uzbekistan on the south. Since the 1960s, the two main sources of water leading into the Aral Sea have been diverted for the irrigation of cotton. The result is one of the largest human-made environmental disasters in the world; today, the Aral Sea, once the fourth largest lake in the world, has lost ¾ of its volume and ½ of its surface area.

People living in the surrounding area have little access to safe drinking water; most sources are saline, and contaminated both biologically and chemically. Diarrhea, hepatitis A, and other water-borne diseases are common. Most families collect water from piped systems, water pumps, or irrigation canals. Even those communities that have water piped from a central system to their homes cannot be sure that water will flow when they turn on the tap. Families and communities need small-scale independent methods to enable them to control their own access to drinking water and to ensure that this drinking water is safe.

One of the possible solutions to the problem is to distill readily available saline water into safe drinking water using solar photovoltaic energy. Photovoltaics (PV) are a technology that converts sunlight directly into electricity. Photovoltaic panels provide an independent electrical power source at the point of use, making it particularly suited to remote locations such as communities surrounding the Aral Sea. An array of PV panels is shown in Figure 1.

Figure 1: Array of photovoltaic panels. Source: ITDG

Project Scope

Your assignment is to design a solar water distiller for an elementary school near the city of Samarkand, Uzbekistan. Assume that the school has 100 students ranging from Kindergarten to Grade 8. In your design, discuss the appropriateness of using PV technology in this particular setting.

Your design should be based on the specifications of the solar energy available, presented in Tables 1 and 2.

Provide a report to Engineers Without Borders outlining your approach to the problem, your conclusions, and any further recommendations you feel should be considered.

You should organize your report into the following sections:

• Executive Summary

• Problem Identification (include Constraints and Criteria)

• Proposed Solution and Justification

• Conclusion and Recommendations

• Appendices (include Calculations)

• References

• Technical sketches or drawings

Design of a Ceramic Water Filter

Materials Engineering

Problem Statement

In Cambodia, a majority of the rural population does not have access to safe water. Although water sources such as open wells, ponds and rivers or lakes are available, these sources are often polluted with biological pathogens. People regularly fall sick when they drink water from these sources, and it is not uncommon for young children to die from water-borne diarrhoeal diseases.

You are a Materials Engineer working for an organization in Cambodia that aims to improve access to safe drinking water in rural areas. Your organization intends to produce a low-cost water purifier that can remove biological pathogens from contaminated water sources, in order to provide enough safe drinking and cooking water for a typical rural household.

The design of the water purifier is a porous pot, made of a kiln-fired mixture of common clay and ground rice husk. The porous clay allows water to seep through while removing turbidity and some pathogens. The clay filter element is also treated with colloidal silver to inactivate any remaining bacteria. The filter element is placed in a receptacle or receiving vessel, which protects the filter element from damage and helps prevent re-contamination of the purified water during storage.

In your design choices, consider the following requirements:

• Capacity of the filter: The flow rate of water through the filter is the primary indicator of filter quality, and also strongly affects user satisfaction. The porosity, and thus the flow rate, is controlled in the initial design by the mix ratio of clay to ground rice husk. A typical household in rural Cambodia has 6 family members. The minimum amount of drinking water that is required is 3L/person/day. A higher flow rate is preferable so that there is sufficient water available for family use, when it is needed. However, a flow rate that is too high indicates a poor quality filter with large voids or cracks, which may not remove pathogens effectively. The maximum acceptable flow rate is 3.0 L/hour. Filters with higher flow rates are rejected.

• Consistent process results: Your organization anticipates a production rate of between 1000 to 2500 filters/month, to be sustained for a minimum of 5 years. The filter production facility must consistently produce high-quality filters with low rejection rates.

• Cost: Cost is a major factor impacting accessibility of the technology to rural householders. Your organization has recently conducted an assessment to determine how much each household would be willing to spend on a water filter. According to this research, the retail cost must not exceed $7.50. The budgeted cost breakdown is:

Item	Cost
Filter element variable costs (raw materials including clay, rice husk, fuel, silver)	$0.50
Filter element fixed costs (including rent, salaries)	$0.75
Depreciation on capital equipment	$0.25
Receiving Vessel	$1.80
Spigot	$1.20
Packaging, marketing, breakage allowance	$1.00
Profit for manufacturer	$1.00
Profit for retailer	$1.00
Total:	$7.50

Project Scope

You have been hired as an engineer to select the best clay and processing method to make the filter element, considering the criteria above.

There are four sources of clay that you can choose from to make the ceramic filter. Table 1 summarizes information you have gathered from visiting the clay suppliers and performing a simple field test. In order to evaluate the clay further, you produced a batch of test tiles and four filter samples using clay from each source. Results of measurements on these sample filters are given in Table 2.

Table 1: Information from clay supplier

Table 2: Measurements from test samples using typical mix ratio of 5.2 kg clay to 1.6 kg rice husk per filter

You are also to recommend which clay processing method to use, based on your own research. Some of the possible clay processing methods include:

• Hand-thrown with a wheel

• Extrusion

• Wheel with jigger-jolly

• Slip-casting

• Press mold

• Coil technique

Provide a report to Engineers Without Borders outlining your approach to the problem, your conclusions, and any further recommendations you feel should be considered.

You should organize your report into the following sections:

• Executive Summary

• Problem Identification (include Constraints and Criteria)

• Proposed Solution and Justification

• Conclusion and Recommendations

• Appendices (include Calculations)

• References

• Technical sketches or drawings

Design of a Software System for a
Medical Supply Distribution Centre

Computer and Software Engineering

Problem Statement

HIV/AIDS is having a devastating effect in the developing world. The scourge is particularly devastating in sub-Saharan Africa, where the average adult prevalence rate is in the order of 7.5%, and over 25 million children and adults are living with HIV/AIDS. Countries such as Swaziland and Botswana have been the hardest hit, with prevalence rates in the order of 35%. AIDS is now the leading cause of death in sub-Saharan Africa, and in 2003, over 12 million children were orphaned. With so many children growing up without caregivers, teachers, and role models, the negative social impacts will, among other things, reinforce the vicious cycle of HIV/AIDS and other causes and effects of poverty.

For those already infected and living with AIDS, the main drug treatment for HIV/AIDS is called antiretroviral treatment (ART). While not a cure, ARTs work by slowing the reproduction of HIV in the body. ARTs can delay the onset of sickness for many years, and allow infected people to live somewhat normal lives.

While health care and access to drugs may be practically universal in a country like Canada, very few African have reliable access to health care. Lack of health infrastructure, inadequate or non-existent transportation systems, and drug costs are only a few of the enormous barriers that are preventing people from accessing drug treatments that could prolong their lives.

Project Scope

In order to facilitate the distribution of drugs and other medical supplies in the developing world, Engineers Without Borders is asking you to design a software system to manage and automate operations at medical supply and drug distribution centres. The clients of these distribution centers may be remote hospitals, rural clinics or individual patients.

To be successful, the software design must address all major concerns of such a centre. These include: storage requirements for the medial supplies and drugs, government-imposed restrictions regarding narcotics, shipping and receiving requirements, tracking individual usage of drugs and supplies, medical supplies that are comprised of several components, authentication of the requests, requests that may be sent in several natural languages and dialects, and many others. It is your responsibility to determine what these issues are though research, and discussion with the clients (your TAs).

The medical supply distribution centre is a place for the warehousing, and dispensing of supplies and drugs to those in need. The centre must obviously account for the storage and inventory management of drugs, employee and patron safety and security, and medical implications of drug use and drug interaction. In many ways this is a great deal like a local pharmacy, however in an area without the infrastructure, access to patient information, and security that one would expect here in Canada. We expect that such a centre would be exclusively servicing a large and medically distressed population and therefore must be capable of dealing with large inventory and large patient volume situations.

Once you determine how you want your system to behave, the software design you produce must include discussion in each of the following areas.

• Breakdown - A discussion of how the system will be divided into parts to accomplish its goals.

• Scenarios - How does the system interact with a specific people to complete a task involved in the business model?

• Error Handling - How will the system deal with situations where the user does not follow the normal business processes?

• Hardware and Logistics - What kinds of machines will be needed for the system to work, i.e. Servers, terminals, handheld scanners. How will these devices interact?

Provide a report to Engineers Without Borders outlining your approach to the problem, your conclusions, and any further recommendations you feel should be considered.

You should organize your report into the following sections:

• Executive Summary

• Problem Identification (include Constraints and Criteria)

• Proposed Solution and Justification

• Conclusion and Recommendations

• Appendices (include Calculations)

• References

• Technical sketches or drawings

Design of a Jatropha Seed Press

Mechanical Engineering

Problem Statement

Many developing countries have no oil resources to call their own, and therefore rely heavily on costly imports to fuel their industry and transportation systems. This dependence makes developing economies particularly vulnerable during periods when oil prices are high. High fuel transportation costs, especially in landlocked countries, can translate to higher prices paid by many who can scarcely afford it, and prohibit many others from purchasing some fuels at all. Scarcity and reliability of supply can be a major challenge in remote areas, where transportation infrastructure is poor or non-existent.

This is just one reason why some countries are beginning to explore the potential of locally developed alternatives to petroleum products. Another major benefit includes the potential for increased small-scale commercial activity in rural areas. This can be from the production of the fuels themselves, or through the use of the fuels to spur growth in other small-scale industries such as agro-processing. Some countries are currently exploring the use of locally processed seed oil, such as the oil from the plant of the Jatropha shrub, as a diesel alternative or a diesel extender. In warm climates, the oil can be used in some stationary engines as a direct substitute without any modification. Jatropha oil is also a good raw material for biodiesel production, which involves the transesterification of the oil, usually at a larger scale. The biodiesel produced can be used in a wider range of diesel engines. Figure 1 illustrates the jatropha seed before it is processed.

Figure 1: Jatropha fruit and seeds. Source: Engineers Without Borders

Oil extraction presses typically utilize a screw mechanism and a cage consisting of separate bars or plates. The clearance between the bars of the cage is about 0.5 mm. Under the pressure build by the action of the screw seed oil is extruded trough the gaps between the bars. Figure 2 illustrates a schematic diagram of the screw mechanism.

Figure 2: Screw mechanism of an oil press. Source: www.jatropha.de

Project scope

The scope of this project is to design a press unit destined for the manufacturing of high quality, cold pressed, jatropha seed oil, suitable for implementation in underdeveloped regions of the world. The design should minimize utilization of components requiring advanced manufacturing technologies and limit the weight of a single component to 40 kg to enable assembly without the assistance of a lifting device. The unit may be motorized or operated manually.

Provide a report to Engineers Without Borders outlining your approach to the problem, your conclusions, and any further recommendations you feel should be considered. The report should include sketches of the press with major components and basic dimensions labeled, and a description of how the device works.

You should organize your report into the following sections:

• Executive Summary

• Problem Identification (include Constraints and Criteria)

• Proposed Solution and Justification

• Conclusion and Recommendations

• Appendices (include Calculations)

• References

• Technical sketches or drawings