Improved waste heat recovery through surface of kiln using phase change material (original) (raw)
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An Experimental Analysis of Waste Heat Recovery Potential from A Rotary Kiln of Cement Industry
2020
Cement production has been one of the most energy intensive processes in the world. Kilns serve as an integral part to produce clinker which is a tool to measure capacity of system. The temperature inside the kiln rises to 1400-1600 C while its surface temperature is between 200-400 C. The thermal efficiency of a kiln is about 55-60% and the remaining heat is lost in the form of flue gases and radiated from the surface. The current study has been carried out at a cement plant in Pakistan for the assessment of waste energy recovery from the surface of a rotary kiln. An experimental setup of small scale waste heat recovery with water heat exchanger has been fabricated at the plant site equipped with necessary instrumentation. Measurements of heat recovery are carried out at different water mass flow rates, surface temperatures, and transverse and radial distances of kiln. Results revealed that maximum water temperature achieved was 25 C at 1.8 kg/min mass flow rate of water at kiln su...
Performance Analysis on Regenerative Heat Exchanger with Paraffin Wax as Phase Change Material
Solar energy is one of the most unused renewable energy in the world. This heat energy can be recovered and stored which can be useful in the conservation of energy. In the present study a regenerative heat exchanger is designed in which phase change material is arranged in the form of Paraffin wax capsules using capsulation technique for faster and congruent charging and discharging due to its porosity. Al2O3 is added with paraffin wax so as to improve the heat conductivity. Aluminium baffles are placed to improve the flow pattern of water which prolongs the hot and cold periods. The present system has been designed and fabricated for storing thermal energy for waste heat recovery in manufacturing sectors. In this study a Flat plate collector is coupled with the heat exchanger for collecting heat in the form of solar radiation and later used to analyse the storage capacity of the heat exchanger using phase change material (PCM) paraffin wax. Experiments are performed for two different mass flow rates. Inlet temperature of the heat transfer fluid is maintained constant during charging process. In order to preserve heat during discharging process, temperature of passing fluid is maintained at atmospheric temperature at cold period. The charging speed and the efficiency of the heat transfer are determined for two different mass flow rates. Calculations for amount of heat stored and released during charging (hot period), discharging (cold period) are performed and heat storage efficiency was determined. The experimental results show the feasibility of paraffin wax as phase change material.
Utilization of waste heat from rotary kiln for burning clinker in the cement plant
E3S Web of Conferences
Cement subsector next to the glass industry is counted among one of the most energy-intensive industries, which absorbs approx. 12-15% of the total energy consumed by the industry. In the paper various methods of energy consumption reduction of in the cement industry are discussed. Cement production carries a very large emissions of greenhouse gases, where CO 2 emissions on a global scale with the industry than approx. 5%. Great opportunity in CO 2 emissions reduction in addition to the recovery of waste heat is also alternative fuels co-firing in cement kilns [1], [2]. In the cement sector interest in fitting-usable waste energy is growing in order to achieve high rates of savings and hence the financial benefits, as well as the environment ones [3]. In the process of cement production is lost irretrievably lot of energy and reduction of these losses on a global scale gives a visible saving of consumed fuel. The aim of this study is to investigate the possibility of waste heat use in Rudniki Cement Plant near to Czestochowa. After analyzing of all waste heat sources will be analyzed the heat emitted by radiation from the surface of the rotary kiln at the relevant facility. On the basis of thermal-flow calculations the most favorable radiative heat exchanger will be designed. The calculations based on available measurements provided by the cement plant, a thermal power of the heat exchanger, the heat exchange surface, the geometry of the heat exchanger, and other important parameters will be established. In addition the preliminary calculations of hydraulic losses and set directions for further work will be carried out. Direct benefits observed with the introduction of the broader heat recovery technology, is a significant increase in energy efficiency of the industrial process, which is reflected in the reduction of energy consumption and costs. Indirectly it leads to a reduction of pollution and energy consumption.
Experimental investigation of a radiative heat pipe for waste heat recovery in a ceramics kiln
Energy, 2018
Following the energy crisis in the 1980s, energy-saving technologies have been investigated and implemented in order to decrease the energy consumption and greenhouse gas emissions of major industrial sectors such as metals, ceramics and concrete. The ceramics industry is still, in Europe, one of the major energy consuming manufacturing processes. Hence energy saving solutions have been investigated in order to decrease the energy consumption of the manufacturing process. The main energyconsuming process is the firing stage with more than 50% of all of the energy required for the process. The energy used during the firing stage is then released during the cooling stage. To improve the heat recovered during the cooling stage, a radiative heat pipe ceiling has been investigated. The heat recovered during the cooling stage is then sent to the drying stage. The proposed system is composed of a radiative heat pipe, a kiln and a ceramics heater. The radiative heat pipe is made of ten parallel pipes of 28 mm diameter and a wall thickness of 2 mm the tubes are connected at the bottom by a 28 mm pipe and a condenser section of 50 mm the condenser is a shell and tube system with 9 pipes of 10 mm. The system was cooled by water. The radiative heat pipe has been tested at different flow rate and ceramics heater temperature. The experimental results shown that the radiative heat pipe was able to recover heat using radiation and natural convection in an enclosed kiln. The system was able to recover up to 4 kW. This paper describes this innovative solution for recovering heat from the cooling stage of an earth roller kiln for tile ceramics manufacturing, transformed into hot clean air for the drying stage of the ceramics manufacturing process.
Materials Today: Proceedings, 2020
Researchers are often trying to find out the various renewable energy sources to continuously feed the growing energy demands as well as storing the generated energy with appropriate known technology. In line of the above, in order to store the energy, phase changing material (PCM) playing the major role. The phase changing materials exhibit better efficiency due to its energy storage capacity, and keep supplies constant thermal energy when need arises. Normally the characteristics of the phase change materials are charging, storing and following this, final step is discharging the heat to the selected medium through the phase changing materials and the same could be used for many applications starts from domestic to industrial spectrum. In this present study, the paraffin wax and hydrogenated vegetable oil have been used as the phase changing materials. To experimentally analyze the coefficient of thermal expansion of the phase changing material, the tube and shell type heat exchanger have been used. Similarly the efficiencies of the thermal energy storage (TES) capacity of the subjected material have been verified, with the intention of employ the same system for the applications like cold storage plant, refrigeration, domestic heating and automobile sectors.
Improvement in Heat Transfer Inside a phase change Energy System
2018
In this work, an experimental and numerical investigation was designed for recover the waste heat from the air conditioning system. The model includes a vertical thermal glass capsule with diameter of 60 mm and length of 300 mm of glass thickness 1.5 mm. The capsule containing paraffin wax as a phase change material (PCM) with 9mm diameter copper tube with U-shaped for passing water flow through it as a discharging heat transfer fluid. The study focusses on the enhancement heat transfer by adding Alumina nanoparticles (AL2O3) with volume fractions (0.5%, 1%, 2% and 3%). The results indicate the effects of AL2O3 decreases melting rate time a proximately 7,15,11,9% besides decreases solidification rate time approximately 4,8,6,5% respectively as compared to pure paraffin. Also, the effect of adding a pair of copper tubes inside the paraffin wax was tested during melting and solidification process. Index Term-Phase change material, paraffin wax, thermal storage, thermal conductivity, n...
Analysis of Thermal Energy Storage system using Paraffin Wax as Phase Change Material
A significant amount of heat is wasted in electricity general, manufacturing, chemical and industrial process. Recovery and reuse of this energy through storage can be useful in conservation of energy and meeting the peak demands of power. A shell and spiral type heat exchanger has been designed and fabricated for low temperature industrial waste heat recovery using phase change material. Paraffin wax (Melting Point 54 o C) was used as storage media due to its low cost and large-scale availability in Indian market. Experiments were performed for different mass flow rates and inlet temperature of heat transfer fluid for recovery and use of waste heat. The effect of mass flow rate on the performance of the system was studied. Calculations for overall heat transfer during charging (melting of PCM) and discharging (solidification of PCM) and heat discharging efficiency were also made.
Mathematical modeling of heat recovery from a rotary kiln
Applied Thermal Engineering, 2010
In this study, heat recovery from rotary kiln was examined for a cement plant in Turkey. At first, an exergy analysis was carried out on the operational data of the plant. Results indicated the presence of 217.31 GJ of waste heat, which is 51% of the overall heat of the process. Then a mathematical model was developed for a new heat recovery exchanger for the plant. It was determined that 5% of the waste heat can be utilized with the heat recovery exchanger. The useful heat obtained is expected to partially satisfy the thermal loads of 678 dwellings in the vicinity through a new district heating system. This system is expected to decrease domestic-coal and natural gas consumption by 51.55% and 62.62% respectively. CO 2 emissions may also be reduced by 5901.94 kg/h and 1816.90 kg/h when waste heat is used instead of coal and natural gas.
Using the adsorption chillers for utilisation of waste heat from rotary kilns
EPJ Web of Conferences, 2018
Waste heat utilisation and its reclamation is important for increasing the efficiency of the electric power production and for decreased consumption of primary energy. Waste heat can be utilised for the electric power production or for manufacturing and processing purposes. According to long-term forecasts, the consumption of electric power with current consumption of about 150 TWh, can be increased to about 230 TWh in around 2040, what may lead to the increased energy consumption from fuels and the increased emission of harmful contaminants to the atmosphere. The cement subsector, next to the glass industry, is among the most power-consuming industries, and it consumes about 12-15% of total energy consumed by industry in total, whereas the CO2 emission from such industry exceeds about 5% in worldwide scale. In the cement sector, there is an increasing need for useful reclamation of waste energy, in order to obtain high energy-saving factors, and hence the financial and environmenta...
Experimental Investigation of Thermal Behaviour of Phase Change Material in a Thermal Store
This paper reports on an experimental thermal energy storage system using phase change material (PCM) and comprising a bench top test rig based on a plate heat exchanger design concept. The research explores the unique properties of PCMs and how they may be used to alleviate peak electricity loads and costs that result from use of heat pumps in domestic buildings by taking advantage of off-peak electricity tariffs. Thermo-physical properties of three different PCMs were tested using a differential scanning calorimeter (DSC) and Hot disk instrument. Paraffin wax (RT 58) with a melting point range of 54 – 62°C was selected for the experimental work. A test rig was made from extruded polypropylene sheet with channels that can carry water, representing one of the plates in the thermal store heat exchanger, and PCM contained on one side of it. A computational model was developed to investigate heat exchange between the heat transfer fluid, polypropylene sheet and the PCM in the store. Th...