Study of Using Solar Thermal Power for the Margarine Melting Heat Process

Margarine as a raw material has a multiple uses in the production of bio-organic materials such as refined oil and butter. It passes through many industrial stages before beginning the process of refining and packaging it to the consumer. One of these important stages is the melting process, which wastes an immense amount of thermal power. The large rate of thermal power consumption occurs due to the huge reservoirs in which the margarine is stored (500 m3–1500 m3 Savola International Company-Suez Gulf region-Egypt). With drawing margarine from the reservoirs is a cost and time intensive process due to the solid state of margarine at environmental temperatures. Dry saturated steam is passed through the heat exchanger pipes inside the reservoir to melt the required amount of margarine. In some cases, this process can take up to 8 h in the summer and 12 h in the winter, which can be amplified by the loss of heat energy from the reservoir throughout the day, especially during the night periods. Moreover, steam boilers that use heavy fuel or natural gas can cause serious environmental damage as a result of emissions, such as the carbon oxide and nitrous oxide compounds. In contrast, solar energy is one of the cleanest and environmentally friendly renewable energies and should be invested as an alternative heat source for the melting process of margarine. As mentioned before, the melting of margarine is considered a heating process that consumes a huge amount of thermal energy. Therefore, solar thermal power can play a vital role in the process of melting margarine. Generally, temperature requirements of solar industrial heat applications range from 60 °C to 260 °C. Cylindrical PTC systems look very promising for delivering industrial heating process applications in the range of 95 °C–350 °C delivery temperature [1]. For solar thermal applications, the operating design conditions of solar collectors should be well above the desired operating conditions of the application to ensure stability of the operation. Therefore, flat plate collectors and evacuated tube collectors are eliminated from this study due to the previous reason and its lower efficiencies compared against the PTC [2]. This is why medium to medium–high temperature solar collectors are used [3,4]. Most of the production processes of the food industry such as milk products, vegetable, meat, fruits, and beer are run at temperatures below or near 100–130 °C. In addition, many cleaning processes such as pasteurizing, sterilizing, drying, hydrolyzing, distillation, washing, polymerization, and cooking processes are conducted under thermal applications [5,6]. Thus, switching to a renewable energy source, such as solar energy, can result in cost savings as well as decrease the negative impacts the production process has on the environment. The production process of margarine requires a large amount of heat in which solar thermal power is a viable and more cost effective source of energy. The problem originally emerged when Savola's company officials (Savola International Company in Margarine industrial Suez Gulf region-Egypt) decided to optimize the time, energy, and cost of the production process. They summarized their problems into the following points: The process of margarine melts takes more than 12 h to obtain 100–200 m3 of melted margarine per day. Which costs the equivalent amount of 476,120 m3 per day of natural gas (100,000 $/month). Reduction of CO2, NO2, and CO emissions is a must according to environmental laws. After reviewing the configuration of their heating process, using solar thermal power as a clean energy alternative seemed to be the most viable solution. Egypt has a great potential for solar energy. It is calculated that an amount of 6–7 kW h/m2/day of global radiation is in the Suez Gulf region-Egypt [8]. Therefore, it is very promising to utilize this vast amount of untapped solar energy in this industrial heating process. The aim of this research is to present a feasibility study, assessing the impact of using solar thermal power as an alternative source of energy in the margarine melting process. In this study, solar PTC is used instead of a conventional steam boiler. Water–steam and/or Therminol-VP1 [7] HTO are utilized through the PTC representing two different configurations. The data results of the conventional configuration (config1) are compared with the PTC–water steam configuration (config2) and PTC–Therminol configuration (config3) according to the hourly cost parameter ($/h). The study plan is organized as follows: The process configurations for the proposed systems are performed and the design limits are investigated. The mathematical model that represents the proposed systems is constructed. Three cases are compared (solar direct vapor generation (two configurations) was conventional configuration). Practical and analytical solutions for the process problems are studied and executed. solar desalination system (SDS) software package (a part of renewable energy desalination system (REDS) that were developed by the authors) was used to model all the system units [8–11]. 2. Margarine Melting Heating Process 2.1. The Process Problems. The problem began when Savola's-Egypt officials decided to evaluate the productive performance of their company. In their current configuration, a steam boiler running on fuels is used in the heating process. The company was faced with several problems identified as below. Wasted time, especially in the winter it requires melting about 100–300 m3 within approximately 12 h. This requires a significant amount of time before the canning process can begin. In addition, the steam boiler has to be operated during night hours to collect the melted margarine early in the morning before the canning process. It is noted that the fuel consumption is also very high, especially in the case of heavy fuel operations. As the average daily consumption reached 1 m3 or more, which is considered to be a high rate of consumption. The exhaust emissions resulting from the combustion inside the steam boiler today are unacceptable in the light of international regulations which intend to reduce global carbon emissions. Because of the temperature difference during the night especially in winter a large amount of thermal power gets wasted. This increases the operation time and the rate of fuel consumption. Thus, Savola's Egyptian officials contacted the authors to investigate and propose solutions to the existing inefficiencies, while at the same time decreasing the negative impact on the environment.