A plant wishes to dry a certain type of sand, a continuous countercurrent dryer is being used to dry 453.6 kg dry sand/hr containing 0.04 kg total moisture/kg dry sand to a value of 0.002 kg total moisture/kg dry sand. The sand was passed through the dryer at a temperature of 26.7 Deg C and it was discharged at 62.8 Deg C. Heated air passed through the dryer at a temperature ok 93.3 Deg C having a humidity of 0.010 kg water/kg dry air and left the dryer at a temperature of 37.8 Deg C. Determine the air flow rate through the dryer and the outlet humidity. Assume the drying process is adiabatic.
Page 1 of 4 CHEMICAL PROCESS DESIGN PRINCIPLES (CPDP311) SEMESTER 2 2021 DESIGN STATEMENT LECTURER: Dr M. LASICH MODERATOR: Prof A.H. MOHAMMADI Background FFX LLC is planning on building a power plant at their chemicals site in the south Durban basin. This plant will generate electricity using natural gas as the fuel, as shown in the preliminary flowsheet below: You will be working in pairs on this project, with one person designing the primary cooling circuit, and the other handling the secondary cooling circuit. The primary circuit flows through the boiler to produce steam, and the secondary cooling circuit absorbs heat from the primary circuit by means of the condenser. You are given the following table of information about the two cooling circuits: Page 2 of 4 Stream 1 2 3 4 5 6 7 H2O flow (kmol/h) 1000 1000 1000 1000 12000 12000 12000 T (oC) 100 767 552 100 78 21 21 P (atm) 10 9.5 2 1.5 1.5 1.0 2.0 The inlet and outlet conditions for the primary circuit are points 4 and 1, respectively. The inlet and outlet conditions for the secondary circuit are points 6 and 7, respectively. The pipe length and number of pipe fittings are related to your student number as follows: Primary circuit pipe length = 12 + X (where X is the last digit of your student number) Secondary circuit pipe length = 60 + X (where X is the last digit of your student number) 90o square elbows = Y (where Y is the second-to-last digit of your student number) In addition to the elbow fittings, you must take into account expansions, contractions, and couplings (as appropriate). You have the following additional restrictions placed on your design work: Fluid velocity must be <3 m/s head losses to be estimated using equivalent pipe diameters the control valve should account for 33% of the total head loss in the pipe design tasks you are to design and sketch the pipe, as well as specifying the location and operating conditions of the pump necessary to move the fluid. you need to determine the following: pipe specifications, such as diameter, material, etc. operating speed of the pump at the design flow rate and at the upper and lower limits of the design margins of ±10% flow rate energy requirements of pumping carbon emissions associated with pumping, as a result of electricity consumption cost of the pipe you have old stocks of schedule 40 carbon steel piping (roughness = 0.046 mm) treated with the proprietary tidus-xtm corrosion resistant coating; the costs of which are given by: c = 19 id0.55 l page 3 of 4 where c is the cost in 1992 british pounds (cpi1992 = 100, cpi2021 = 218, gbp:zar ≈ 20.00), id is the internal diameter in mm, and l is the length in m. the pipe cost c includes all fittings, including a control valve. you can use the friction factor correlation of swamee and jain (1976)1: f = 0.25 / [log10(ε / {3.7 d} + 5.74 / re0.9)]2 where f is the friction factor, ε is the absolute roughness in m, d is the internal pipe diameter in m, and re is the reynolds number. ffx llc has developed its own proprietary pumps, the auron-xtm, and the auron-x2tm, which have reliably predictable characteristics. you have to use an ffx llc auron-xtm or an auron-x2tm pump in your design. an auron-xtm pump costs r0.65 million, and an auron-x2tm pump costs r0.85 million. the performance of the pumps is the same, regardless of the connecting nozzle size. nozzle connections are available in all standard pipe sizes. the head delivered by an auron-xtm pump operating at 2900 rpm with an impeller size of 200 mm is given by: h = –0.0224 q2 + 0.6548 q + 169.57 while for an auron-x2tm pump operating at 2900 rpm with an impeller size of 600 mm the equivalent expression is: h = –0.0003 q2 + 0.1045 q + 39.214 where h is the head delivered in m, and q is the liquid flow rate in m3/h. the npsh required for an auron-xtm pump is given by: npsh = 0.033 q2 – 0.031 q + 1.9286 whereas for an auron-x2tm pump the npsh requirement is given by: npsh = 1×10-5 q2 +0.0036 q + 0.619 where npsh is the net positive suction head required by the pump (in m) and q is again the flow rate in m3/h. as part of your design, you should determine a suitable location for the pump in terms of its position along the pipe. the efficiency of an auron-xtm pump can be reliably predicted as a function of the flow rate as follows: η = –0.0476 q2 + 1.9524 q + 56.429 whereas the efficiency of an auron-x2tm pump can be reliably predicted as a function of the flow rate as follows: η = –0.0008 q2 + 0.3661 q + 38.095 where η is the efficiency in percent, and q is the flow rate in m3/h. the grid emission factor for electricity on the eskom grid2 is 960.64 gco2eq/kwh. 1 swamee, p. k.; jain, a. k. explicit equations for pipe-flow problems. journal of the hydraulics division 1976, 102, 657-664. 2 climate transparency. brown to green: the g20 transition to a low-carbon economy; climate transparency, c/o humboldt-viadrina governance platform: berlin, 2018. page 4 of 4 assessment the design report will be used to assess the following ecsa graduate attributes (gas): ga 7—impacts of engineering activity and sustainability ga 10—engineering professionalism you should consult the rubric and ga checklist to understand how your work will be assessed. your report should be typed in font size 10 or 11 using either times, times new roman, arial, or calibri. you should justify the text to both margins and use 1.5 or double line spacing. referencing should be done using the american chemical society (acs) reference style. all submissions will be undertaken via turnitin. your work must be submitted in pdf format. only work submitted via your own profile on turnitin will be accepted. all other work will receive a mark of zero. deadlines the design report will be submitted no later than the end of the sixth week after the start of the semester. late submissions will receive a mark of zero. students who submit their work and fail to satisfy all of the gas but otherwise pass will be given an opportunity to resubmit their work, after which their mark for that assessment will be capped at 50 % provided they satisfy all ga requirements and pass the submission itself. only one resubmission per assessment will be allowed. m/s="" ="" head="" losses="" to="" be="" estimated="" using="" equivalent="" pipe="" diameters="" ="" the="" control="" valve="" should="" account="" for="" 33%="" of="" the="" total="" head="" loss="" in="" the="" pipe="" design="" tasks="" you="" are="" to="" design="" and="" sketch="" the="" pipe,="" as="" well="" as="" specifying="" the="" location="" and="" operating="" conditions="" of="" the="" pump="" necessary="" to="" move="" the="" fluid.="" you="" need="" to="" determine="" the="" following:="" ="" pipe="" specifications,="" such="" as="" diameter,="" material,="" etc.="" ="" operating="" speed="" of="" the="" pump="" at="" the="" design="" flow="" rate="" and="" at="" the="" upper="" and="" lower="" limits="" of="" the="" design="" margins="" of="" ±10%="" flow="" rate="" ="" energy="" requirements="" of="" pumping="" ="" carbon="" emissions="" associated="" with="" pumping,="" as="" a="" result="" of="" electricity="" consumption="" ="" cost="" of="" the="" pipe="" you="" have="" old="" stocks="" of="" schedule="" 40="" carbon="" steel="" piping="" (roughness="0.046" mm)="" treated="" with="" the="" proprietary="" tidus-xtm="" corrosion="" resistant="" coating;="" the="" costs="" of="" which="" are="" given="" by:="" c="19" id0.55="" l="" page="" 3="" of="" 4="" where="" c="" is="" the="" cost="" in="" 1992="" british="" pounds="" (cpi1992="100," cpi2021="218," gbp:zar="" ≈="" 20.00),="" id="" is="" the="" internal="" diameter="" in="" mm,="" and="" l="" is="" the="" length="" in="" m.="" the="" pipe="" cost="" c="" includes="" all="" fittings,="" including="" a="" control="" valve.="" you="" can="" use="" the="" friction="" factor="" correlation="" of="" swamee="" and="" jain="" (1976)1:="" f="0.25" [log10(ε="" {3.7="" d}="" +="" 5.74="" re0.9)]2="" where="" f="" is="" the="" friction="" factor,="" ε="" is="" the="" absolute="" roughness="" in="" m,="" d="" is="" the="" internal="" pipe="" diameter="" in="" m,="" and="" re="" is="" the="" reynolds="" number.="" ffx="" llc="" has="" developed="" its="" own="" proprietary="" pumps,="" the="" auron-xtm,="" and="" the="" auron-x2tm,="" which="" have="" reliably="" predictable="" characteristics.="" you="" have="" to="" use="" an="" ffx="" llc="" auron-xtm="" or="" an="" auron-x2tm="" pump="" in="" your="" design.="" an="" auron-xtm="" pump="" costs="" r0.65="" million,="" and="" an="" auron-x2tm="" pump="" costs="" r0.85="" million.="" the="" performance="" of="" the="" pumps="" is="" the="" same,="" regardless="" of="" the="" connecting="" nozzle="" size.="" nozzle="" connections="" are="" available="" in="" all="" standard="" pipe="" sizes.="" the="" head="" delivered="" by="" an="" auron-xtm="" pump="" operating="" at="" 2900="" rpm="" with="" an="" impeller="" size="" of="" 200="" mm="" is="" given="" by:="" h="–0.0224" q2="" +="" 0.6548="" q="" +="" 169.57="" while="" for="" an="" auron-x2tm="" pump="" operating="" at="" 2900="" rpm="" with="" an="" impeller="" size="" of="" 600="" mm="" the="" equivalent="" expression="" is:="" h="–0.0003" q2="" +="" 0.1045="" q="" +="" 39.214="" where="" h="" is="" the="" head="" delivered="" in="" m,="" and="" q="" is="" the="" liquid="" flow="" rate="" in="" m3/h.="" the="" npsh="" required="" for="" an="" auron-xtm="" pump="" is="" given="" by:="" npsh="0.033" q2="" –="" 0.031="" q="" +="" 1.9286="" whereas="" for="" an="" auron-x2tm="" pump="" the="" npsh="" requirement="" is="" given="" by:="" npsh="1×10-5" q2="" +0.0036="" q="" +="" 0.619="" where="" npsh="" is="" the="" net="" positive="" suction="" head="" required="" by="" the="" pump="" (in="" m)="" and="" q="" is="" again="" the="" flow="" rate="" in="" m3/h.="" as="" part="" of="" your="" design,="" you="" should="" determine="" a="" suitable="" location="" for="" the="" pump="" in="" terms="" of="" its="" position="" along="" the="" pipe.="" the="" efficiency="" of="" an="" auron-xtm="" pump="" can="" be="" reliably="" predicted="" as="" a="" function="" of="" the="" flow="" rate="" as="" follows:="" η="–0.0476" q2="" +="" 1.9524="" q="" +="" 56.429="" whereas="" the="" efficiency="" of="" an="" auron-x2tm="" pump="" can="" be="" reliably="" predicted="" as="" a="" function="" of="" the="" flow="" rate="" as="" follows:="" η="–0.0008" q2="" +="" 0.3661="" q="" +="" 38.095="" where="" η="" is="" the="" efficiency="" in="" percent,="" and="" q="" is="" the="" flow="" rate="" in="" m3/h.="" the="" grid="" emission="" factor="" for="" electricity="" on="" the="" eskom="" grid2="" is="" 960.64="" gco2eq/kwh.="" 1="" swamee,="" p.="" k.;="" jain,="" a.="" k.="" explicit="" equations="" for="" pipe-flow="" problems.="" journal="" of="" the="" hydraulics="" division="" 1976,="" 102,="" 657-664.="" 2="" climate="" transparency.="" brown="" to="" green:="" the="" g20="" transition="" to="" a="" low-carbon="" economy;="" climate="" transparency,="" c/o="" humboldt-viadrina="" governance="" platform:="" berlin,="" 2018.="" page="" 4="" of="" 4="" assessment="" the="" design="" report="" will="" be="" used="" to="" assess="" the="" following="" ecsa="" graduate="" attributes="" (gas):="" ="" ga="" 7—impacts="" of="" engineering="" activity="" and="" sustainability="" ="" ga="" 10—engineering="" professionalism="" you="" should="" consult="" the="" rubric="" and="" ga="" checklist="" to="" understand="" how="" your="" work="" will="" be="" assessed.="" your="" report="" should="" be="" typed="" in="" font="" size="" 10="" or="" 11="" using="" either="" times,="" times="" new="" roman,="" arial,="" or="" calibri.="" you="" should="" justify="" the="" text="" to="" both="" margins="" and="" use="" 1.5="" or="" double="" line="" spacing.="" referencing="" should="" be="" done="" using="" the="" american="" chemical="" society="" (acs)="" reference="" style.="" all="" submissions="" will="" be="" undertaken="" via="" turnitin.="" your="" work="" must="" be="" submitted="" in="" pdf="" format.="" only="" work="" submitted="" via="" your="" own="" profile="" on="" turnitin="" will="" be="" accepted.="" all="" other="" work="" will="" receive="" a="" mark="" of="" zero.="" deadlines="" the="" design="" report="" will="" be="" submitted="" no="" later="" than="" the="" end="" of="" the="" sixth="" week="" after="" the="" start="" of="" the="" semester.="" late="" submissions="" will="" receive="" a="" mark="" of="" zero.="" students="" who="" submit="" their="" work="" and="" fail="" to="" satisfy="" all="" of="" the="" gas="" but="" otherwise="" pass="" will="" be="" given="" an="" opportunity="" to="" resubmit="" their="" work,="" after="" which="" their="" mark="" for="" that="" assessment="" will="" be="" capped="" at="" 50="" %="" provided="" they="" satisfy="" all="" ga="" requirements="" and="" pass="" the="" submission="" itself.="" only="" one="" resubmission="" per="" assessment="" will="" be="">