# Energy Recovery via Thermal Gasification from Waste Insulation Electrical Cables (WIEC)
## 2 Materials and Methods
### Gasification Test  
The gasification tests were performed on an AllPowerLabs PP20 Power Pallets - a gasifier with a power of 15 kW, illustrated in Figure 1, a common downdraft reactor that is combined with an electric power generator and an electronic control unit. The equipment consists of a storage silo, where the biomass is simultaneously dried by recirculating the hot gases produced in the reactor. Fuel is supplied from the top as the air moves downward, being preheated through contact with the reactor's walls. It should be noted that the gasifier admits grinded raw material, with dimensions between 1 to 4 cm. Pine biomass had these characteristics and was grinded before the process. Insulation residues for electrical cables (WIEC) have dimensions between 0.2 and 1 cm, that is, they have been reduced during the metal removal process.  
At the bottom of the reactor there is a char collection system, using an endless screw, which pushes the unconverted material into an accessory tank. The synthesis gas leaves the reactor at a temperature between 450 to 550 \({}^{\circ}\)C. Downstream of the reactor there is a cyclone filter, which removes the finer particles that follow with the synthesis gas produced. Then the synthesis gas is taken to a heat exchanger, whose function is to reduce the temperature of the synthesis gas to below 100 \({}^{\circ}\)C and, at the same time, to heat the biomass found in the hopper. Subsequently, the synthesis gas is cleaned through a filter composed of biomasses of various granulometries. In this filter, there are the retention of tars, which are condensed there. The clean synthesis gas, with a temperature of 50 to 70 \({}^{\circ}\)C, can be collected for analysis or injected directly into the engine. Condensed matter is collected at the bottom of the biomass filter  
Figure 1: Gasifier schematics adapted from [28].  
The Otto cycle internal combustion engine (ICE) burns the gas providing kinetic energy for the generator. In order to start the engine according to the manufacturer's instructions, the temperature in the reactor's lower part (reduction zone) must be at least 400 \({}^{\circ}\)C.  
The tests were carried out in co-gasification with pine, biomass material that presents some good characteristics for gasification and produces low ash/char content. For the beginning of the experiment it was used 100% pine forest residue, which was the standard biomass for the tests.  
During each test, lasting 180 minutes, some parameters were controlled, namely the values of temperature (the temperature sensors are welded outside the reactor, next to the air inlet) and pressure in the upper and lower parts of the reactor (oxidation and reduction zones, respectively), pressure in the biomass particle filter, inlet airflow rate and lastly the amount of biomass consumed during the test. The gas samples were collected from the biomass particle filter into suitable bags with the aid of a vacuum pump in the minutes 60, 120 and 160, for all the experiments. The chars were trapped in the bottom of the reactor and in the cyclone filter, which was downstream of the reactor. The condensates were collected at the bottom of the biomass particulate filter.