Impregnation of Calcium Chloride on Activated Carbon Surface

Impregnation of Calcium Chloride on excited Carbon SurfaceThis effect of solar refrigerator is based on some key parameters like ammonia water carrying capacity, adsorption rate, awaken tape transport mechanism, stability etc., this paper presents the pervertwise detailed preparation of con self-coloredated atomic number 20 chloride impregnated on the resurrect on emotional coulomb. Ammonia was charged into the electron nihility metro containing blocks under high twinge of 7 bars was applied during initial charging session and total adsorption was not frostingd in 25 legal proceeding and the solve was repeated. The total amount of ammonia adsorbed was 2.4 kg and was capable of taking more ammonia. Agglomeration effect was totally avoided by the even distribution of calcium chloride on the return air of activated speed of light. Carbon was activated at imposing temperature of 700 C for optimum properties.1. IntroductionSolar infrigidation and heat warmness be m achines that work on wide range of temperature, especially when ammoniates or ammonia derivatives are involved as sorbents wherefore temperature mint range from -50oC to 300oC 1. Furthermore it is environmentally benign and it does not contribute to global warming or ozone stratum depletion. They do not usually utilize CFCs or HCFCs as colds.This compositors case of refrigeration is based on the phenomena of adsorption which is a surface phenomenon in which one is adsorbent and second is adsorbate or cold. dickens main types of adsorbents are used, one is physical adsorbent like activated one C in which the adsorbate/refrigerant is adsorbed on its surface by week Vander Waals forces. This processis dep deathent on the surface knowledge base of adsorbent. It is said that one gram of activated carbon has an area equal to the area of a tennis yard. The piling of adsorbate/refrigerant adsorbed in this process is really less because of weak Vander Waal forces. The second typ e of adsorbent is chemical adsorbent like Calcium chloride. When it comes to sorption capacity we use chemical adsorbents. The mass of refrigerant incorporated here could be as high as 1.05 kg/kg salt 2. solely there are two serious concerns with this, one is granular salts have very low caloric conductivity and second is the agglomeration phenomenon. The salts after some cycles of adsorption and desorption it undergoes it swells, compacts and agglomerates, which leads to drastic reduction of the surface area and ultimately reduces the adsorption capacity. Wang et al. 3 mixed activated carbon with calcium chloride salt which overcame the phenomenon of agglomeration and observed a constant adsorption capacity. Lu et al. 4 observed specic cool down power ranging from 111.2 to 865.8 W/kg victimisation adsorption ice setr. Vasiliev et al. 5 used carbon fiber with calcium chloride and reported to have increased heat and mass transfer phenomena and overcome agglomeration. Later Maura n et al. patented a process to make impregnated consolidate blocks of calcium chloride and activated carbon. Han and lee side 6 found the thermal conductivity of different salts impregnated in spread out plumbago blocks and measured values blind drunk to 50 W m-1 K-1 when the amount of grow graphite was 70%.Ammonia is used as refrigerant and the process of chemisorption is governed the following two basic equations.1. CaCl2.2NH3+2NH3 CaCl2.4NH32. CaCl2.4NH3+4NH3 CaCl2.8NH3This process of impregnation of calcium chloride on the surface of activated carbon not only ensures uniform distribution of calcium chloride on the surface of activated carbon but similarly avoids agglomeration over m any synthesis cycles. Balat and Spinner 7 reported that the texture of expanded graphite favors the mass transfer of the adsorbate/refrigerant which leads to improved kinetics when activated carbon combine with a salt is used in the chemisorption system.Experimental Setup and ResultsThe follo wing stairs were performed during ecesis of coordination compounds blocks of calcium chloride and activated carbonHeat treatment of calcium chloride and activated carbon, Making etymon of pee and calcium chloride and mixing it with expanded graphite, Impregnation of calcium chloride in expanded graphite Calcination of hydrated calcium chloride into calcium chloride, Grinding of the dried impregnated mixture of calcium chloride and activated carbon and finally formation of consolidated blocks from powder obtained from grinding.Heat treatment of carbonIn the experiment performed by Wang et al 6 the expanded graphite is heated at the temperature of 300oC. But according to Han et al the temperature of the heat treatment influences the degree of expansion and these authors evince on the importance of expanded graphite at temperature higher than 600oC to ensure a proper expansion. Han and his confrere 9 too noted that the graphite expanded at temperatures in a higher place 700oC h ad the lowest densities and at least double the porosity of expanded graphite treated at 500oC. The expanded graphite used has the chemical reputation assumption in table.The heat treatment of carbon powders was carried out to increase its porosity and to make the contaminants from the carbon powders. Carbon powders were placed in container and placed in an electric oven at 100oC for 7 hours in influence to remove the moisture circumscribe contained in it. 2kg of carbon powders were placed in two separate aluminum vessels in the oven at 100oC for 7 hours. After this it is placed in desiccators to avoid assiduity of moisture contents till the start of the second process. In the last step heat the carbon powders obtained from the first step in vacuum at 700oC in a electron vacuum organ pipe furnace for a dwell time of 14 proceeding.ProcedurePut small amount of carbon powders in blind stainless firebrand tube of diameter 1.5 inches and length 15 inches and press them with a rammer so that the tube can hold a maximum amount of carbon powders. After placing the carbon powders in the tube seal the open end of the vacuum tube with wire gauze with mesh and cotton cloth in order to prevent imbibe of carbon powder by vacuum pump connected through a plate at the open end, tight the end cap of the tube to avoid infiltration of air into the tube. If air enters the tube in the heating process underway simply oxidation of the powder takes place. Then Place the tube in the tube furnace and connect it with the vacuum pump to remove the air entrapped in the tube and any other residual gases produce during heating of carbon powders. In the experiment by Wang et al. 2 expansion of graphite above 700 C has no significant effect on the reduction of the density of activated carbon also Hans 3 and coworkers shows that carbon expanded at a temperature of 700 C has lowest density and twice the porosity as compared to expansion at 500 C, so the temperature of the furnace i s set at 700 oC giving a kurrat rate of 10 oC/minute. When the temperature of the furnace reached 700 oC we set the machine at a dwell time of 14 minutes in order for carbon powder to undergo full expansion. After that the furnace was turned off and the tube was allowed to cool down. When the furnace cools down remove the carbon powders from the tube and stored it in a desiccator. The furnace takes one and a half(prenominal) hour to reach 700oC and 2 hours for cooling the tube as a result this process took us a lot of time. About 150 grams of carbon powder were expanded in a iodin run. This process was repeated until a total mass of 2.4 kilograms of expanded graphite was obtained.Tube used for safekeeping the carbon powder in tube furnaceA tube was designed to hold the carbon powders in the tube furnace. The tube was made of stainless poise which can withstand high temperature of the tube furnace. A metal plate is welded to one end of the pipe to permanently close one side of t he pipe and the other end was left open for pouring the powders into the tube. A cap was made to seal the open end of the pipe after filling with the carbon powders. The cap has an extension pipe for connecting the tube with the vacuum pump. A 300 grid mesh was used before the cap and cotton cloth was also applied to avoid the suction of carbon powders into the vacuum pump. The cap itself is made of two metal plates. bingle plate has a groove of 3 mm depth and a diameter equal to the pipe diameter which holds the tube in place. The two plates were bolted with each other through four nuts and bolts.The specifications of the tube are given belowTotal length30 in diam of tube1.5 inVolume of tube0.000376m3Density of carbon450 kg/m3Mass of carbon0.1693 kgTable.2 dimensions of vacuum tubeHeating of calcium chlorideHeat treatment of calcium chlorides was also carried out remove the moisture content and any contaminants in it.2. Experimental procedureThe following steps are carried out dur ing the heat treatment of the calcium chloride.Since calcium chloride salt is very hygroscopic in nature and it absorb moisture very easily. Put 4kg of calcium chloride salt in stainless steel vessels and covered the mouths of the vessels with aluminum foils. Small holes were made in aluminum foil for the moistures and gases to escape out of the vessels. These vessels were then placed in an oven at a temperature of 100oC for 10 hours to remove the moisture contents out of the calcium chloride salt. After heating calcium chloride salt at 100oC. It is then placed in desiccators to avoid the absorption of moisture by the salt until next step.Preparation of solution of calcium chloride and activated carbon utilise distilled irrigateAfter the heat treatment of calcium chloride and activated carbon 60% salt solution of calcium chloride in distilled water is prepared. 4kg of calcium chloride and about 7 liters of distilled water was used for making solution. Activated carbon is then rut tish thoroughly in bottle and poured into the solution of calcium chloride salt and stirred for some time for uniform mixture. Based on the result of Wang et al. 6 best performance is shown when calcium chloride and expanded graphite are mixed in the ratio of 41.Figure 60% solution of calcium chloride and waterFigure mixture of solution of calcium chloride and activated carbonImpregnation of calcium chloride in expanded graphiteThe solution is then dried for 10 hour at 110 0C in an electric oven to remove free water and allowImpregnation of calcium chloride in expanded graphite.This find out shows the final shape of uniform mixture of activated carbon and calcium chloride salt when it loses all water in an electric oven.Calcination of hydrated calcium chloride into anhydrous calcium chlorideAfter impregnation of calcium chloride on the surface of expanded graphite the solution is again heated in an oven at 250oC for 7 hours to calcinate the calcium chloride as a result the hydrate d calcium chloride become anhydrous.CaCl2.nH2O CaCl2 + nH2OGrindingWhen the solution is dried and dehydrate in the electric oven the mixture is grinded in the grinding machine to make fine powder of the composite materials. The fine powders are then placed in desiccators in order to avoid the absorption of moistures by the powders until the next process.Die used for making consolidated blocksIn order to compress the obtained the powder above under pressure of 10 MPa using UTM it is placed in the mold shown below. The die consists of a cylindrical tube, a piston, a metal plate at the bottom of cylindrical tube and stainless steel rod. The cylindrical tube, metal plate and piston is made of mild steel. Graining of piston and cylindrical tube is done to make the surface smother so that block would not stuck in it after crunch under immense pressure. No binder was used in the compaction of powder into consolidate blocks. precondition of cylinder are given belowThickness of cylindrical tube is 5mm and its height is 152.4 mm.Internal diameter is 50 mm.Specification of piston are given belowHeight is 15 inDiameter of piston is 49mmThe piston having a hole at its center is lengthwise whose inner diameter is 15 mm.Figure Die for making consolidated blocks of calcium chloride and activated carbonConsolidate blocks FormationTo make hollow cylinder of obtained powder under UTM following steps were followed.The resulted powder (impregnated with calcium chloride) are poured into the cylindrical part of the die through funnel, then a piston is placed on the top and a small load is applied manually to make the powder a bit compressed. The die is liveted in a UTM and pressed under 10MPa of load. 10Figure composite blocks of calcium chloride and activated carbonThe composite blocks are placed inside the test unit, experiments were performed and test results were analyzed.RESULTS AND CONCLUSIONSEPERIMENTAL PROCEDURE FOR CHARGINGCharging of ammonia required great care because it is very dangerous and can cause blindness and even death when come in contact with human. then during charging great care should be taken and all the safety rules must be followed.Before charging ammonia make sure that entire setup is leak proof and there is no leakage during charging or after charging. Compressor is connected to the root line and whole system is evacuated from air and its noted that either vacuum is created or not by taking reading through pressure gauges attached to generator line. By performing these entire tests and conforming that no leakage is present the system is passed through the following steps.s.no.Initial pressure before chargingFinalpressure after chargingTime taken until 0 barMass adsorbed1st run-1 bar6.0 bar25 min600 grams2nd 0 bar7.0 bar39 min700 grams3rd 0.4 bar8.0 bar30 min500 grams fourth 0.5 bar10 bar49 min750 grams1.First of all generator line is heated for 3 hours at 100oC with the vacuum pump connected to remove the gases adsorbed in the adsorbent. This process is called degasing.2.Secondly the system is evacuated using vacuum pump and it is placed idle for 30 minutes to find out whether any leakage is occurring or not.3. After the system is evacuated the compressor along with all measure is detached from generator line and ammonia charging hose is placed in place and tight fit is ensured.4. Then charging line is connected with ammonia cylinder. The valve pipe connecting the ammonia tank and generator line is supplied with a manual valve. Initially the valve is opened slowly to flood the ammonia into the generator line, the pressure inside the generator line starts increasing. As ammonia starts adsorbing inside the pipe the pressured reduces while the manual valve is opened and closed at the succession of the processes.5. After charging the system is closed using manual value to stop the further hang of ammonia and wait until the pressure in the system reduces due to adsorption of ammonia in the adsorbent materia l.6.When the pressure reaches its minimum level the system is charged with ammonia again and wait until the pressure in the generator line decreases.7.This process is repeated until 2.4kg of ammonia is charged into the system.The experimental data achieved during charging of the system is given in table givenThe total amount of ammonia charged into the system was about 2.4 kg.The mass of ammonia was find out using digital graduated table. The generator line is placed on the scale and mass is noted before and after charging. In this way mass of ammonia adsorbed is find out.CONCLUSIONSThe powders were successfully activated using available research facility.Impregnation of calcium chloride on the surface of activated carbon greatly enhances its ammonia carrying capacity and adsorption rate.The phenomena of agglomeration and swelling as depicted by literature aspect was completely overcome and heat and mass transfer was efficiently enhanced.Because no binder was used in the blocks so blocks were made under relatively high compression using UTM.References1 E.E. Anyanwu, Environmental pollution restructuring the refrigeration Industry as a way out, Int. J. Environ. Protect Eng. (2000).2 Wang LW, Wang RZ, Wu JY, Wang K, Wang SG. Adsorption ice makers for shing boats driven by the scan heat from diesel engine choice of adsorption pair. Energy Convers Manage 2004 45 2043-57.3.R.G. Oliveira*, R.Z. Wang1, C. 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