The pyrolysis can be an attractive way to reduce the plastic waste and, in the same time, to obtain alternative conventional fuels. In this respect, four polymers (low-density polyethylene, high-density polyethylene, propylene and polystyrene) were used in the pyrolysis process. The experiments were carried out by using an in-house plant, which allowed a maximum test temperature of 450 �C. The product oil and the derived gas from the pyrolysis process were evaluated using different techniques, such as elemental analysis (EA), calorimetry, gas chromatography (GC), gas chromatography coupled with mass spectrometry (GC-MS). Furthermore, for a comparative study two catalysts, zeolite and lignite, were also used for the pyrolysis process, in order to observe their influences on the final products. The higher heating value obtained for the oil was in the 40.17-45.35 MJ/kg range, acceptable for the use of these oil as an alternative fuel for diesel engine. Also, the sulphur content from the obtained oil does not cause environment problems, being lower than the allowed limits (10 mg/L). In addition, the pyrolysis derived gas was rich in hydrocarbons, conducting to a high calorific value, in the 73.42 - 121.18 MJ/kg range.

The study aims to promote clean energy technologies that ensure the recycling and recovery of waste, namely the sewage sludge (SS), by converting it into products (e.g. oil, gas) with added value, contributing thus to reducing the negative impact on environment and health. An experimental setup was proposed in order to achieve the pyrolysis process, by varying the heating rate, (5�C/min, 10�C/min and 50�C/min). The resulted products, namely i) char - SSPyChar, ii) oil - SSPyOil and iii) gas - SSPyGas, were investigated in terms of elemental content, high heat value (HHV), low heat value (LHV) and emission factor (EF). The pyrolysis oils obtained with lower heating rate, 5�C/min and 10 �C/min, presented higher HHV, in comparison with the oils obtained at 50 �C/min, which were rich in water. These oils can have a negative impact on the environment, through their combustion due to their high content of N (6 wt%) and S (1.2 wt%), responsible for the formation of NOx and SOx. Pyrolysis gas revealed in its composition high contents of hydrocarbons (C1-C6), carbon dioxide (CO2) and hydrogen (H2). The highest HHV was obtained by using 5�C/min increment, namely 33.81 MJ/m3. Also, the pyrolysis gases had comparable energy values with natural gas, biogas or gases resulted from the plastic pyrolysis.

The increased demand for energy sources is the driving force to convert organic compounds into alternative fuels. Plastic waste disposal affects the environment, since they are not easily recycled and, during the recycling process, they can produce waste ash, heavy metals, or potentially harmful gas emissions. In the plant design for plastic converting into fuel, the chemical reactor is one of the advanced equipment in the field of chemical and process engineering. This study emphasizes the feasibility of pyrolysis process for valorisation plastics by producing energy-efficient products. In this respect, samples of polypropylene, polyethylene and polystyrene were used as models and subjected to pyrolysis processes at 450 �C, in the presence of two types of mesoporous silica materials, MCM-41 and SBA-15, using a modern developed reactor. The use of mesoporous materials increased the calorific value of the obtained oil and gas, thus improving the economic potential of the process end products. This study dealt with the extraction of oil from plastics termed as plastic pyrolysis oil (PPO) and plastics pyrolysis gas (PPG), with a composition rich in different types of hydrocarbons and they can be marketed at much cheaper rates compared to that present in the market.

The study tried to contribute to solving two serious environmental issues: CO2 reducing and sewage sludge disposal. Thus, sewage-sludge-derived materials were obtained in order to be evaluated for CO2 adsorption capacity. Therefore, the char resulted after the sewage sludge pyrolysis was subjected to oxidation and chemical activation processes by using different quantities of alkaline hydroxide. One of the obtained materials, activated with a lower quantity of alkaline hydroxide, was also treated with acid chloride. Further, the materials were structural and texturally characterized, and material treated with acid chloride was used for CO2 adsorption tests, due to high surface area and pore volume. The handmade system coupled to a gas chromatograph allowed the adsorption efficiency evaluation using different feed gases (rich and poor in CO2) by completed purge of pipe line and on-line check. Additionally, the adsorption capacity, separation efficiency, and CO2 recovery were calculated. Taking into account the values for adsorption capacity (separation efficiency and CO2 recovery), it can be concluded that the sewage sludge derived material could be a promising solution for CO2 reduction and waste disposal.