THE PARAMETERS OF CLEANING A CIP SYSTEM AFFECTED

Transcription

1 Chemial and Proess Engineering 017, 38 (1), DOI: 11515/pe THE PARAMETERS OF CLEANING A CIP SYSTEM AFFECTED ENERGY CONSUMPTION AND CLEANING EFFICIENCY OF THE PLATE HEAT EXCHANGER Joanna Piepiórka-Stepuk *, Jarosław Diakun, Marek Jakubowski Koszalin University of Tehnology, Faulty of Mehanial Engineering, Department of Food Industry Proesses and Failities, Raławika 15 17, Koszalin, Poland This paper presents a study on the effet of leaning fators on the energy onsumption of the leaning proess in a CIP system, and the orrelation between single omponents of eletriity neessary to perform this proess and the leanliness degree obtained. Studies were arried out in a laboratory leaning station, wherein a plate heat exhanger ontaminated with hot milk was inluded. The researh program was developed aording to a 5-level statistial plan. Based on the results, obtained with Experiment Planner 1.0, a regression funtion of energy requirement onsidering variables suh as: leaning time, temperature and flow rate of the leaning liquid via the leaned exhanger has been developed. Desribing this relationship, linear and quadrati funtions with double interations were used. Signifiane level for the analysis was established at α = 05. Correlation analysis between omponents of the eletriity neessary to perform the leaning proess (pump drive and heating of the leaning agent) and the resulting degree of leaning of heat exhanger plates was performed. Keywords: leaning, CIP system, energy onsumption, leaning parameters, leanliness, leaning effiieny 1. INTRODUCTION The food industry is a major onsumer of water and energy. Furthermore water and energy are interrelated with wastewater prodution (Krzemińska et al. 013). The demand for agro food proessing failities for water and energy is dependent on many fators (Kowalzyk and Karp, 005; Steinhoff-Wrześniewska et al., 013; Williams and Anderson, 006; Wojdalski et al., 013). The basi ones inlude tehnology of food proessing, tehnial equipment, degree of automation and mehanization of prodution operations, thermophysial properties of materials, requirements for produts, magnitude and struture of prodution and its organization (Bunse et al., 011; Marhini et al., 014; 015; Wojdalski and Dróżdż, 01) and related with those the operations of leaning and disinfetion of mahines and prodution equipment. Some reports indiate that the leaning proesses in food industry are energy-intensive proesses and that in the food industry they require even about % of the total proess energy onsumption (Neryng et al., 1990; Pawełas, 010; Rad and Lewis, 014). This onsumption primarily results from the operation onditions of the CIP leaning station, type and size of the objets subjeted to leaning and the hoie of leaning agents (Piepiórka- Stepuk et al., 016; Ramirez et al., 006; Wojdalski et al., 013). Studies onduted by many authors on leaning of milk installations suggest that energy requirement of leaning proess in flow mainly results from the neessity of heating a large volume of leaning agents in storage tanks (even up to *Corresponding author, joanna.piepiorka@tu.koszalin.pl pe.zasopisma.pan.pl; degruyter.om/view/j/pe Download Date 1/15/17 1:57 PM 111

2 J. Piepiórka-Stepuk, J. Diakun, M. Jakubowski, Chem. Proess Eng., 017, 38 (1), C) and maintaining their appropriate temperature throughout the leaning time (Berlin et al., 007; Diakun et al., 01; Eide et al., 003). Eletriity onsumption for this aspet of the leaning proess exeeds twelve times that neessary to fore the flow of leaning agents. Other studies regarding the seletion of optimum leaning onditions in the CIP system demonstrate that it is possible to inrease the degree of leanliness of washed installation with a simultaneous redution of energy onsumed (Jude and Lemaire, 014; Piepiórka-Stepuk et al., 016). For the proess optimization is neessary to develop a funtion whih is a mathematial desription of this proess ontaining the variable fators. In the available literature, there are no reports on the theoretial and analytial modeling desribing the effet of leaning agents in flow (time, temperature and flow rate) on energy intensity of this proess. Moreover, there are no experimental results, based on whih we ould infer the harater of interations between these fators and energy onsumption of the proess. The objetive of the study was to develop a regression funtion desribing the relationship between the amount of energy neessary to perform the proess of leaning of a plate heat exhanger and different fators, suh as time, temperature and flow rate.. MATERIALS AND METHODS.1. Constrution of researh station and researh program Experiments were onduted using a two-tank leaning station in the CIP system (1, ) (Fig. 1), wherein S4 IT PN 10 (1) (Sondex) plate heat exhanger was inluded (Table 1). One of the tank installations () had a built-in heater of 3 kw power and thermal insulation, whih enabled the preparation of leaning solutions of a speified temperature and restrited heat loss into the environment. Heater power supply aomplished through a thermostati ontrol system whih allowed heating and stabilization of liquid temperature in the tank. Water of different temperatures was prepared in this tank. Fig. 1. Sheme of a laboratory CIP station. Legend: K ondutivity meter; ph ph-meter; M turbidity meter; KP omputer ard; P pressure gauge; P pressure drop between inlet and outlet of the heat exhanger; W flow rate meter; F inverter; E 1 onsumed energy meter used to power the pump; E onsumed energy meter used to heat the leaning liquid; T thermometer; 1 objet to be leaned (plate heat exhanger); insulated tank with a heater; 3 non-insulated tank; 4 pump; 5 omputer 11 pe.zasopisma.pan.pl; degruyter.om/view/j/pe Download Date 1/15/17 1:57 PM

3 The parameters of leaning a CIP system affeted energy onsumption and leaning effiieny Table 1. Main geometrial harateristis of the plate heat exhanger used in the study Geometrial harateristis Symbol Unit Value Effetive length of the plate L w m 381 Effetive width of the plate L s m 111 Area of a single plate A= L w L s m 04 Area of heat transfer A m 378 The largest distane between plates b m 008 Mean distane between the plates = (b/) m 004 Surfae area of the flow ross-setion P str = L s m 0005 Wetted perimeter Ob = + L s m 3 Total number of plates in the heat exhanger N p items 11 Number of hannels in the plate heat exhanger N = (N p 1)/ items 5 Hydrauli diameter of the hannel d h m 009 Corrugation angle β 60 Type of plates Straight - flow Table. Cleaning programs used in the researh Level of the researh plan T (min) Variables T (C) u (ms -1 ) Reynolds number Re (-) pe.zasopisma.pan.pl; degruyter.om/view/j/pe 113 Download Date 1/15/17 1:57 PM

4 J. Piepiórka-Stepuk, J. Diakun, M. Jakubowski, Chem. Proess Eng., 017, 38 (1), The leaning system was equipped with an impeller pump (4) and meters for measuring the quantities haraterizing the flow, i.e. flow rate in the pipeline (W), pressure (P) and the pressure drop between the inlet and the outlet of the heat exhanger ( P). Furthermore, the system had sensors whih registered hanges in the properties of the washing liquid, i.e. temperature (T), turbidity (M), ondutivity (K), ph (ph), eletriity required to heat the washing liquid (E 1-PM 390 meter, Elektro- Trading ompany) and and to power the pump (E -C-5 three-phase eletriity meter, Inventor ompany). All the proess data were reorded (5). The leaning proess was arried out only with pure water. The plan of the study overed the leaning proess inluding the fators for whih variability was within the range: leaning time t = min; mean flow rate between plates of the heat exhanger alulated based on the flow rate measured in the pipeline u = ms 1 ; temperature of the washing liquid T = C. The researh program was developed aording to a 5-level statistial plan , based on whih we ould obtain an experiment matrix presented in Table... Evaluation of energy onsumption of the proess and leaning effiieny For test purposes, a single measuring yle overed milk ontamination of plates, installation of the heat exhanger and leaning in flow with simultaneous measurement of energy requirement of pump drive (E Pi) and heating the leaning agent (E Gi). Total energy onsumption of the leaning proess was alulated aording to Eq. (1) (Wojdalski et al., 01). E C = E Pi +E Gi (kwh) (1) After ompletion of the leaning proess, the exhanger was disassembled and using the Clean-Trae TM Surfae Protein Plus swab tests based on Cu + -indued olor reation and protein omplexes, information on the amount of residual protein ontaminants was obtained (Piepiórka-Stepuk, 01). The degree of purity was determined on a 0 10 point sale, in whih 0 denoted an initial ontamination of plates with milk, and 10 points - desired purity of plates (lak of any ontaminants). All plates in the exhanger were evaluated, in five idential areas on the plate of 5.0 m 5.0 m in diameter. Based on test results, the overall average leanliness of the heat exhanger plates (J M) was determined from Eq. (). ( J MOi) J M () m Studies were arried out in tripliate for eah set of fator values. After olleting the experimental study results, the Pearson orrelation oeffiient whih defines a linear relationship between the energy onsumption (E Pi; E Gi) and the total onsumption (E C) in the leaning proess and the purity of plate exhanger (J M), was alulated. Furthermore, for eah leaning program, leaning effiieny (C E) ould be alulated aording to Eq. (3). It was defined as the inrease of leaning degree in 1 kwh of energy. J M 1 CE (3) E kwh C.3. Methodology for the development of regression funtion of energy onsumption in the leaning proess The obtained results onstituted a basis to develop a regression funtion desribing the energy onsumption of the leaning proess in the CIP system of the plate heat exhanger in a funtion of 114 pe.zasopisma.pan.pl; degruyter.om/view/j/pe Download Date 1/15/17 1:57 PM

5 The parameters of leaning a CIP system affeted energy onsumption and leaning effiieny time, temperature and average flow rate in the gap between E C plates (t, T, u ). To desribe the proposed relationship, linear and quadrati funtions with double interations (4) were proposed. Linear omponents determine the trend of linear harater of interations of single fators on the energy intensity of the proess, while the square omponents an be used to determine the optima of interations for eah fator, deviations from non-linearity and extremes. Y E k k t k T k u k tt k tu k Tu k t k T k u (4) C Calulations were done in the Experiment Planner 1.0 software, aording to the method desribed by Kukiełka (00) and Diakun et al. (01) for a signifiane level of α = 05. Based on the obtained results, ten unknown oeffiients of the model equation were determined; k 0; k 1; k ; k 3; k 1; k 13; k 3; k 11; k ; k 33. Results of the experimental study were subjeted to statistial analysis aording to the following algorithm: elimination of results affeted by a gross error; alulation of inter-row variability and standard deviation; evaluation of variane homogeneity in the sample; alulation of the oeffiients in the regression funtion; statistial analysis of the regression funtion; evaluation of signifiane of multidimensional orrelation oeffiient; assessment of the adequay of mathematial model; regression funtion deoding; determination of the onfidene intervals. The resulting equation desribes the funtion of the energy onsumption of plate heat exhanger leaning. The obtained funtion was presented in a graphial form as a onfiguration of different fators. 3. RESULTS AND DISCUSSION 3.1. Analysis of regression model desribing energy onsumption in the leaning proess Based on study results obtained and statistial analysis, we developed a regression funtion desribing the total energy onsumption in the leaning proess. Multidimensional orrelation oeffiient for the adopted lass of mathematial model was R = 993. After taking into aount non-signifiant fators whih were highlighted in the equation by a ontinuous line, the regression funtion as a seond degree polynomial with double interations, takes the following form enoded as Eq. (5): Y E x1 3.1x 1x3 567x1x (5) 15x x 50x x 14x 476x 005x The F-Snedeor test showed that there were no grounds to rejet the hypothesis about the signifiane of the multidimensional orrelation oeffiient and there were no grounds to rejet the hypothesis on the truth of the regression oeffiients. The ritial value of the F-Snedeor test for the analysis was estimated at F kr = 3.0, resulting in the inequality F E = > F kr = 3. After deoding, the funtion desribing the energy onsumption of leaning the plate heat exhanger is desribed in the following form: E t 133T 1.8u 0008( tt ) (6) 038( tu ) 39( Tu ) 0001( t ) 0011( T ) 1 3 pe.zasopisma.pan.pl; degruyter.om/view/j/pe 115 Download Date 1/15/17 1:57 PM

6 J. Piepiórka-Stepuk, J. Diakun, M. Jakubowski, Chem. Proess Eng., 017, 38 (1), Considering onfidene interval for the obtained funtion (7), the funtion is desribed as (8): E 0484 t T t 65 T t 65 T E C 4 u t 65 u 7. 5 C C 55 1 T 45 u (7) u E E (8) The obtained funtion desribes the energy onsumption of the leaning proess of the plate heat exhanger in flow, under ertain onditions and researh sope adopted. Minus introdued in the beginning denotes a ertain inonsisteny, beause when substituting zero values with t, T, u fators, a negative value of energy is obtained. It results from the fat that the lowest temperature of the leaning agent, for whih the studies were arried out, was 10 C and therefore the developed equation is true only within the tested range. Cleaning below this temperature value is onsistent. A similar situation ours in terms of square of the temperature and the time. Energy onsumption during the proess should be linear, whih means that eletriity onsumption should be proportional to the duration of a given operation or proess. From the resulting funtion it an be onluded however, that time in the quadrati funtion is also important in leaning proesses. It results from a onstant need to heat the leaning solutions during the proess in order to maintain the leaning temperature at the assumed level. The longer the proess of leaning, the more frequent the heater was run to ompensate for heat losses into the environment and maintain thermal onditions. In onsequene, it leads to deviation of the funtion from non-linearity. As a result of statistial analysis, it an be onluded that within the tested range, the square of the flow rate (u ) on energy requirement (E C) is non-signifiant. The impat of leaning parameters on energy onsumption of the proess was graphially presented in Figure, as a onfiguration of two variables. Fators whih are not present on the plots have fixed, entral values of the researh program: t = 65 min; T = 45 C; u = 55 ms 1. Fig.. Total energy onsumption E as a funtion of temperature (T), flow rate (u ) and time (t): a relationship between energy onsumption as a funtion of temperature and flow rate; b relationship between energy onsumption as a funtion of time and flow rate; relationship between energy onsumption as a funtion of temperature and time The graphial form of the funtion onfirms that energy onsumption of the proess inreases with temperature of the leaning fator, whih is onsistent with previous reports (Diakun et al., 01). This relationship for the leaning time equal to t = 65 minutes is linear with maximum for T = 80 C (Fig. a). Inrease in a flow rate of the leaning agent affets energy onsumption of the proess to a small extent (Fig. b). However, a different effet is exerted by leaning time whih is related to 116 pe.zasopisma.pan.pl; degruyter.om/view/j/pe Download Date 1/15/17 1:57 PM

7 The parameters of leaning a CIP system affeted energy onsumption and leaning effiieny temperature up to whih leaning agents are heated. At low temperatures, extension of the leaning time does not affet the overall energy inrease, while for high temperatures, it leads to its inrease by almost 100% (Fig. ). It mainly results from ooling of the leaning agent with time, resulting from temperature differene between the tank and the heated liquid, as well as ooling by the leaned objets, whih ours immediately after starting the installation. As a onsequene of ooling, the leaning agent was ontinuously heated in order to maintain the temperature at an assumed level, whih affeted the form of equation. 3.. Analysis of the effiieny of leaning in relation to total energy requirement In Fig. 3, we summarize the obtained values of the energy requirement (E Pi; E Gi) and total energy onsumption (E C) in leaning proess for eah trials of the researh program aording to Table. Fig. 3. The degree of leaning of plate heat exhanger for single omponents (E Pi and E Gi) and the total (E C) energy requirement in partiular trials of the researh program: a eletriity neessary to heat and maintain temperature of the leaning liquid; b-eletriity neessary to drive the pump; -overall average purity of plates of the heat exhanger. The onduted studies demonstrated that within the programs, in whih the highest total eletriity onsumption (program 4 and 11-about 1 kwh) was reported, no satisfatory results of leaning were obtained. The maximum leanliness of the surfae of heat exhanger plates for these leaning programs, reahed the value of less than 5 points. For those programs the least leaning effiieny a about 39 was ahieved. A similar effet of leaning (between 4 5 points) was obtained for the program 1, for whih we reported the lowest total energy onsumption (1 kwh) related solely to the operation of the impeller pump during leaning. In this program, the highest oeffiient of leaning pe.zasopisma.pan.pl; degruyter.om/view/j/pe 117 Download Date 1/15/17 1:57 PM

8 J. Piepiórka-Stepuk, J. Diakun, M. Jakubowski, Chem. Proess Eng., 017, 38 (1), effiieny was ahieved (3.91). The value of the Pearson orrelation oeffiient for the total energy onsumption (E C) and obtained purity of exhanger plates (J M) was r = 01, what indiates a lak of relationship between the variables whih were analyzed. The obtained results also demonstrated that the main reason for high energy onsumption in the proess of leaning of the dairy installations, is high temperature of leaning agents in the range of C (Rad and Lewis, 014; Ramirez et al., 006), although aording to presented results, this fator does not improve the effiieny of removal of milk residues from the exhanger plates (programs 3, 4, 11). Similar results were obtained by Diakun et al. (01) and Wojdalski et al. (013). The Pearson orrelation oeffiient for these variables (E Gi; J M) was r = 17, indiated a negative orrelation between the analyzed variables. When interpreting this result, we an onlude that with inrease in the amount of eletriity onsumed for heating rinsing water, the effiieny of removal of milk residues from the installation dereases. Properties of milk residues may be an explanation for that phenomenon as they are not dissolved in high temperature of the leaning liquid (Almeija et al., 009; Changani et al., 1997; Fryer et al., 006). Analysis of the study results also showed that with an inrease in the eletriity neessary for the operation of the impeller pump, effetiveness of the heat exhanger leaning is inreasing. The Pearson orrelation oeffiient for these variables (E Pi; J M) was positive and aounted for r = 74. This was onfirmed by the study results obtained in the leaning programs 6 and 13, in whih eletriity onsumption to fore the flow of leaning liquid was the highest (about.5 kwh) with the highest leaning effiieny of the heat exhanger (about 7 points). The leaning effiieny oeffiients for these programs were in range of Thus, inrease in the flow rate during the leaning proess not only improves the leaning effiieny, as observed by other authors (Goode et al., 010; Fryer et al., 006), but also affets the redution of osts assoiated with performane of the proess with simultaneous dereasing of the temperature of leaning agents. 4. CONCLUSIONS Energy onsumption in the leaning proess is mainly related to heating the leaning media and maintaining them at a ertain level. The obtained results indiate that in ase of milk residues whih are formed during hightemperature treatment of milk on plates in heat exhangers, high temperature of rinsing water does not always provide a better end result of the leaning. Negative orrelation was reported between the requirement for the eletriity assoiated with heating of the leaning liquid and the effiieny of removal of milk residues from the plates of the heat exhanger. Requirement for energy related to foring the flow is muh lower in omparison to the requirement for heating the washing liquid. Flow rate is a leaning fator whih leads to the improvement of the leaning quality with its inrease. There is a high orrelation (r = 74) between the energy neessary to drive the pump and the effiieny of washing plates of the heat exhanger ontaminated with milk. In the eologial and safety aspets of food prodution, it is advised to use possibly high flow rates of the leaning media (u = 75; Re ) at the ost of very high temperature (T = 80 C) and very long leaning time (t = 10 min). 118 pe.zasopisma.pan.pl; degruyter.om/view/j/pe Download Date 1/15/17 1:57 PM

9 The parameters of leaning a CIP system affeted energy onsumption and leaning effiieny SYMBOLS m sample size (the produt of the number of areas on a single plate and the number of plates subjeted for evaluation): m = 5 t leaning time, min u mean flow veloity per hannel, ms 1 C E leaning effiieny, kwh -1 E Gi energy of heating and temperature maintenane of leaning agents, kwh E Pi pump power supply, kwh E C total energy onsumption in the leaning proess, kwh J M effetiveness of leaning of the heat exhanger plates J MOi leanliness of a single area on subsequent plates of the heat exhanger T temperature of the leaning liquid, C Re Reynolds number REFERENCES Almeija M.C., Martinez-Ferez A., Guadix A., Paez M.P., Guadix E.M., 009. Influene of the leaning temperature on the permeability of erami membranes. Desalination, 45, DOI: 11016/j.desal Berlin J., Sonesson U., Tillman A.M., 007. A life yle based method to minimize environmental impat of dairy prodution through produt sequening. J. Cleaner Prod., 15, DOI: 11016/j.jlepro Bunse K., Vodika M., Shönsleben P., Brülhart M., Ernst F.O., 011. Integrating energy effiieny performane in prodution management gap analysis between industrial needs and sientifi literature. J. Cleaner Prod., 19, DOI: 11016/j.jlepro Changani S.D., Belmar-Beiny M.T., Fryer P.J Engineering and hemial fators assoiated with fouling and leaning in milk proessing. Exp. Therm Fluid Si., 14, DOI: 11016/S (96) Diakun J., Mierzejewska S., Kukiełka K., 01. The regression equation of energy requirement in the proess of leaning the pipeline by CIP method. Polish Journal of Food Engineering, 1/4(1), 5 8. Eide, M.H., Homleid, J.P., Mattsson, B., 003. Life yle assessment (LCA) of leaningin-plae proesses in dairies. LWT Food Si. Tehnol., 36, DOI: 11016/S (0) Fryer P.J, Christian G.K., Liu W., 006. How hygiene happens: physis and hemistry of leaning. Int. J. Dairy Tehnol., 59, DOI: 11111/j x. Goode K.R., Asteriadou K., Fryer P.J., Piksley M., Robbins P.T., 01 Charaterizing the leaning mehanisms of yeast and the impliations for Cleaning In Plae (CIP). Food Bioprod. Proess., 88, DOI: 11016/j.fbp Jude B., Lemaire E Optimising lean-in-plae proesses in food and beverage operations: Part 1. Proess Control Systems. Available at: Kowalzyk R., Karp K., 005. Energy onsumption at sewage treatment in seleted plant of dairy industry. Problemy Inżynierii Rolnizej, 4, Krzemińska D., Nezaj E., Parkitna K., 013. Zastosowanie reakji Fentona do wspomagania biologiznego ozyszzania śieków z przemysłu mlezarskiego. Annual Set The Environment Protetion, 15, Kukiełka, L., 0 Basis of engineering researh. PWN, Warszawa, Marhini D., Rinaldi M., Montanari R., Bottani E., Solari F., 014. Performane analysis of the water supply system of a dairy ompany by means of an advaned simulation tool. Int. J. Food Eng., 10, DOI: 11515/ijfe Marhini D., Rinaldi M., Montanari R., Bottani E., Solari F., 015. Temperature analysis of the water supply system of a dairy ompany by means of a simulation model. Int. J. Food Eng., 11, DOI: 11515/ijfe Neryng A., Wojdalski J., Budny J., Krasowski E., 199 Energy and water in agro-food industry. WNT, Warsaw, , pe.zasopisma.pan.pl; degruyter.om/view/j/pe 119 Download Date 1/15/17 1:57 PM

10 J. Piepiórka-Stepuk, J. Diakun, M. Jakubowski, Chem. Proess Eng., 017, 38 (1), Pawełas A., 01 Energy effetiveness on the example of the brewery. Agro Industry, 3-4, Piepiórka J., 01. Comparison of evaluation methods degree of leaning surfae prodution in the CIP system. Polish Journal of Food Engineering, /4(), 3 6. Available at: 01/.01/5_art_piepiórka-stepuk.pdf. Piepiórka-Stepuk J., Diakun J., Mierzejewska S., 016. Poly-optimization of leaning onditions for pipe systems J. and plate heat exhangers ontaminated with hot milk using the Cleaning In Plae method. J. Cleaner Prod., 11, DOI: 11016/j.jlepro Rad S.J., Lewis M.J., 014. Water utilisation, energy utilisation and waste water management in the dairy industry: A review. Int. J. Dairy Tehnol., 67, 1- DOI: 11111/ Ramirez C.A., Patel M., Blok K From fluid milk to milk powder: Energy use and energy effiieny in the European dairy industry. Energy, 31, DOI: 11016/j.energy Steinhoff-Wrześniewska A., Rajmund A., Godzwon J., 013. Water onsumption in seleted branhes of food industry. Inżynieria Ekologizna, 3, Williams P.J., Anderson P.A., 006. Operational ost savings in dairy plant water usage. Int. J. Dairy Tehnol., 59, DOI: 11111/j x. Wojdalski J., Dróżdż B., 01. Energy effiieny of food proessing plants key issues and definitions. Polish Journal of Food Engineering, 3/4(3), Wojdalski J., Dróżdż B., Piehoki J., Gaworski M., Zander Z., Marjanowski J., 013. Determinants of water onsumption in the dairy industry. Pol. J. Chem. Tehnol., 15, DOI: 1478/pjt Wojdalski J., Kaleta A., Dróżdż B., Chojnaka A., 01. Fators influening the energy effiieny in dairy proessing plants. TEKA Commission of Motorization and Energeti in Agriulture, 1(1), Reeived 08 April 016 Reeived in revised form 6 Deember 016 Aepted 04 January pe.zasopisma.pan.pl; degruyter.om/view/j/pe Download Date 1/15/17 1:57 PM