Module 9005 Assignment: Filtration-Adsorption
Part AFiltration -Background and Task
Filtration and drying are two important unit operations in most pharmaceutical and chemical processes and are usually carried out in series. In the aspirin production process you will have conducted mass and energy balances over the filter. Based on these balances, critically examine a number of filtration options and select what you consider to be the most suitable types, giving your reasons.
Filtration unit operation:
The stream from the crystalliser is fed to a filtration unit (feed composition is based on the mass balance performed in Module 9001). Laboratory tests havegiven the following data. (Assume an incompressible filter-cake and that the resistance related to the filter medium and initial layer is negligible)
The filter cake porosity = 0.1
Filtrate specific gravity = 1.0 kg per litre
Specific resistance of the filter-cake, r = 8.0 x 1013 m-2.
Filtrate viscosity, μ = 1.0 x 10-3 Ns m-2
Design vacuum and pressure filtration units for the required duty. Support your argument with clear references to both authoritative literature and your design calculations.
After washing, the filter-cake is pre-dried down to 2.0%w/w water in the filtration unit before being fed to the dryer.
Guideline assessment matrix for this assignment
% / A85-100 / B
70-84 / C
55-69 / D
40-54 / E
Below 40
Literature survey
15 / Excellent realisation of objectives / Very good realisation of objectives / Good majority of objectives
realised / Fair amount of objectives realised / Fail does not realise objectives
Selection criteria
15 / Excellent research of material / Very good research using library and www / Some research in library or www / Limited use of references / Has not read up on subject
Sizing/ Calculation
40 / Excellent theoretical work and theoretical analysis and solutions / Very good theoretical work and theoretical analysis and solutions / Good theoretical work and theoretical analysis and solutions / Fair amount of theoretical work and theoretical analysis and solutions / Fail does not realise objectives
Filter – dryer survey
15 / Excellent survey / Very good survey / Good survey / Fair survey / Fail does not realise objectives
(50 marks)
Part BFiltrationlab
There is a lab demonstration on the filtration rig in G40. Students should present a full report on the experiment. A complete set of data and the marking scheme will be given during the laboratory demonstration
(30 marks)
Part CAdsorption
Answer BOTH problems:
Problem No. 1:
Adsorption on 6x10-mesh activated carbon is being considered to recover methyl ethyl ketone (MEK) from an air stream at 25 oC and 1 atm. The airflow is 12,000 std ft3/min, and the air has 0.4 lb MEK/1000 std ft3. If the superficial velocity is 0.5ft/s, and an adsorption cycle of at least 8 h is desired, what bed dimensions should be used? Assume the bulk density of the carbon is 30 lb/ft3.
Problem No. 2:
Granular carbon is used to remove phenol from an aqueous waste. If 10x20 –mesh carbon is used with a superficial velocity of 0.03m/s, estimate the number of transfer units in a bed 4 m deep. The effective diffusivity in the particles can be taken as 0.2 times the bulk diffusivity.
Guideline assessment matrix for this part
% / A85-100 / B
70-84 / C
55-69 / D
40-54 / E
Below 40
Theoretical work and or mathematical analysis and solution
60 / Excellent realisation of objectives / Very good realisation of objectives / Good majority of objectives
realised / Fair amount of objectives realised / Fail does not realise objectives
Research
30 / Excellent research of material / Very good research using library and www / Some research in library or www / Limited use of references / Has not read up on subject
Standard report format presentation
10 / Excellent presentation / Very good presentation / Good presentation / Fair presentation / Poor presentation
(2x10 marks)
Final Submission Date for this assignment is 21/04/09