SCHEDULING OF THE REFINING PROCESSES
It is very important to schedule all the processes in a refining plant because it helps the us to plan how long each reaction will take and how much products we can expect at the end of the day. Working towards a goal of 20’000tonnes of Sunflower Oil to be produced by the end of each year, it is necessary to calculate roughly the reaction time in each process so that the size of reaction vessels required can be worked out. Apart from estimating roughly the time taken at each stage of the refining process, we also included the size of the reaction vessels that would be required by using a simple formula (for continuous stirred tank reactor):
This formula was used for the neutralisation process as it is a continuous process.
Finally the timing:
After a detailed analysis of the processes, the timing for each process in the different production stages was calculated. In total the first batch of refined sunflower oil can be obtained in 24 hours and 17 minutes. After this time the production will be continuous. The operating time of the plant is 6,000 hours per year. With timing calculated, the refinery plant is able to meet the target of 20,000 tonnes per year.
ENVIRONMENTAL IMPACT
The production of a chemical plant in any area will certainly affect the local environment. By building a chemical plant you will need to take over a lot of land. This land could just be wasteland. However, this wasteland although not occupied by humans will be a habitat for some organisms the destruction of this habitat therefore will ultimately lead to the destruction of the organisms. If the plantation is next to an urban area it will cause problems with the local inhabitants. Mainly due to the fact that it is widely known that many chemical plants contain toxic substances and are generally quite dangerous. Noise pollution will also be a major unwanted issue for the local people. Certain species of chemicals have been commented on below to give an assessment of the potential hazards to the surrounding environment.
NaOH
Sodium Hydroxide is a dangerous chemical. It is not possible to simply dump the sodium hydroxide into the environment. Its properties suggest that if it contaminates a source of water any form of life that comes into contact with it will be most likely be burnt or even blinded (if the eves are exposed), given the strength of the concentrations been used.
Secondly if it’s simply dumped out into the environment any contact with aluminium
would cause the production of hydrogen gas:
2Al(s) + 6NaOH(aq) → 3H2(g) + 2Na3AlO3(aq)
Hydrogen gas is easily ignited so large scale fires are possible devastating the environment. If released into the environment there is a chance that it may vaporize causing it to contaminate the air supply. Any organisms sharing the environment may breathe in the contaminated air causing damage to their respiratory system. Thirdly if the sodium hydroxide leaches into the soil then it will have inhibit the growth and survival of the plants. The sodium hydroxide will dissolve into the water causing the plants to dehydrate by osmosis.
Therefore it must be stored in an area which has a corrosion resistant concrete floor. It must also be separated from metals, food, feedstuffs and strong acids. Appropriate storage means the chemical can be kept and reused in the industrial process. Without any environmental damage
H2
The hydrogen produced from the industrial process is extremely hazardous. Releasing this into the atmosphere would be very dangerous for two reasons. Firstly hydrogen is very explosive. So releasing it into the atmosphere could result in it been ignited causing large scale explosions and fires thus devastating the environment. Secondly inhalation of air largely contaminated with hydrogen would result in Therefore the hydrogen must be extracted appropriately and stored in appropriate tanks.
Fullers Earth
So when it is dumped in the ground, and mixes with water, the metal ions seep into the ground water. This release of metal ions is not a major problem and will not disrupt the environment to a major extent. Unless huge amounts of the substance are dumped then the effects on the environment will negligible. However the substance must be left in a designated area in strictly controlled amounts.
Fatty acidsBecause of the nature of the fatty acids they must be treated by a suitable fat recovery process.
SAFETY ASSESSMENT
Hazard analysis of the plant
It is an important task for chemicals engineering to perform a safety assessment of the entire plant by highlighting the major hazards. The next step is to implement measures that could be taking to minimise the hazards. Each stage of the process was analysed to look for any possible hazards and then they were tabulated as shown blow.
Safety Assessment of Chemicals used and produced
Sodium HydroxideThe process uses 5M Sodium Hydroxide which is harmful to the eyes, can cause long term damage and it is also corrosive. When sodium hydroxide dissolves in water the reaction is strongly exothermic. Eye protection must be warm with all personnel who come into contact with sodium hydroxide in order to prevent eye damage. When disposing of large quantities of sodium hydroxide it is essential that is neutralized first, as it is a strong alkali.
Fuller’s EarthFuller’s Earth is harmful if inhaled and it is and irritant to the eye and respiratory systems. So it is recommended that masks are worn also along with a form of eye protection.
HydrogenHydrogen is flammable and forms an explosive mixture with air with compositions from 4% to 70%. For this reason hydrogen must be well ventilated when it is in the reactor and precautions must be prevented against ignition.
Soap (Sodium Stearate)Soap is an irritant to the eye and also to the skin. The soap can cause inflammation to the eye and it is recommended that all those that come into contact with the soap must wear eye protection.
Fatty AcidsFatty acids are carboxylic acids which are weak acids but they are an irritant to the eye. Therefore eye protection should be worn by anyone who comes into contact with them when they are being removed.
ESTIMATION OF THE COST OF PRODUCING THE REFINED SUNFLOWER OIL
A note on costs
The price for a commodity or service is dependant upon the market conditions and the situation of both the supplier and the buyer as well as the cost of production. Many chemicals are interrelated in the market place.
For example Sodium Hydroxide is produced along with Chlorine from Sodium Chloride by electrolysis. Increased demand for one will increase the availability of the other and possibly reduce it price. Commonly there is a cost difference of at least a factor of 2 between different
markets for the same materials. Generally material in its home market, that is the same country of production of the material, will be cheaper than the same material imported a great distance. The economics of a process plant are often dependant on location, you may profit from one country but make a country in another.
Therefore, taking these pointers into account, we have researched several suppliers for crude Sunflower Oil from different countries in order to select the best in quality yet being the most cost effective.
Cost of Sunflower Oil feed:
1. MODERN TECHNOLOGIESRussian Sunflower seed extract supplier in bulk
Not refined fragrant sunflower oil: £0.42/ltr with delivery CIF1
2. NAZCOArgentinean supplier in bulk
Crude sunflower oil: £0.50/ltr w/o delivery CIF
5ltr PET bottles in 40ft container
3. AGRIOILUkraine supplier in bulk, gso@radiocom.net.ua
Crude sunflower oil: £0.40/ltr
Given these three choices for raw oil, the Russian raw sunflower oil was the one chosen for this project. This is because it was the most cost effective including delivery and it is the best quality oil.
Cost of other feed :
Hydrogen: £20/100m3 ≈ £2.22/kg [volume × density (0.0899kg/m3) =mass]
Sodium Hydroxide 50%: £60/tonne
Raney Nickel Catalyst: £1515.83/10kg ≈ £152/kg
Fullers Earth: £87.68/50lbs ≈ £0.795/kg
Other costs:Demineralised water: £1.00/tonne
Steam at 1000 kPa: £6.50/tonne
Cooling water: £0.025/tonne
Electricity: £0.05/kWh
Labour cost (ave. £12.5/hr including overheads and supervision)
For 6000hrs/yr operation: £75000/yr
UK Environmental Agency
Cost of registration as hazardous waste producer = £18/yr (online) £28/yr (paper)
List of wastes considered hazardous can be found at:
www.opsi.gov.uk/SI/si2005/20050895.htm
Cost of Producing Refined Sunflower Oil per year
After researching different sources, the total production cost for refining 20,000
tonnes of sunflower oil is 28.4 million Sterling Pounds. This figure includes price of
raw sunflower oil, chemicals involved in the process, labour cost for employees,
and environmental registration.
Date of project completion: May' 2007.
Link to:
SUNFLOWER OIL REFINERY PART I click
HERE
SUNFLOWER OIL REFINERY PART II click
HERE
