*2.3.1 Experimental procedure*

The experiments were conducted to determine the influence of the pyrolysis temperature at a heating rate varying from 7 to 28°C.min�<sup>1</sup> for seeds and from 10 to 70°C.min�<sup>1</sup> for shells. The experiments were carried out in an apparatus designed with a cylindrical semi-batch reactor, in the shape of a vessel made of stainless steel, inserted vertically into an electrically heated oven (**Figure 3**). The temperature is controlled by a PID controller. The biomass sample (seeds or cistus shells) is introduced into the reactor during pyrolysis. The vapors generated from the reactor were condensed in a condenser cooled with chilled water. **Figure 3** represents the experimental setup.

After each experiment, the condensed liquid is collected in the cylindrical measuring device. After pyrolysis, the solid residue was collected and weighed. The sample


#### **Table 3.**

*Calorific values of the raw material.*

*Valorization of Forest Waste for the Production of Bio-oils for Biofuel and Biodiesel DOI: http://dx.doi.org/10.5772/intechopen.105366*

#### **Figure 3.**

*Pyrolysis experimental set-up. Description: (1) elevator, (2) vertical tube farnace, (3) biomass sample, (4) pyolysis reactor, (5) temperature controller (PID), (6) water out, (7) condenser, (8) water in, (9) gas release, (10) ice bath, (11) condensate, (12) liquid, and (13) metal support.*

**Figure 4.** *Photography of reactor.*

inlet of biomass and charcoal were solid measured by the electro weighing machine balance with an accuracy of 0.01 g.

#### *2.3.2 Pyrolysis reactor*

The reactor is a fixed bed (**Figure 4**). The detailed drawings are provided in part (2.3.1). It consists of a 310 AISI47 refractory stainless steel tube with an internal diameter of 60 mm and a total height of 150 mm. The head of the reactor is removable so that the bed can be introduced and then recovered at the end of the experiment. The whole reaction zone, between the diffuser and the gas outlet at the top of the reactor, has a total height of 150 mm. It includes the bubbling bed and the disengagement zone.

## **3. Results and discussion**

To carry out this study we are obliged to fix the other parameters like particle size and heating rate as well as residence time. We introduce 15 g of the cistus seeds into the reactor which is fed with an electric current. The different results will be presented in the following sections. The yields of different pyrolysis products are calculated by the difference between the initial weight and the final weight which is the solid (char) that remains in the reactor. The liquid (Bio-Oil) which is taken in a graduated cylinder and the percentage of gas escaped to the atmosphere were calculated by the following relationship:

$$\text{\textquotedblleft Gas} = \mathbf{100} - (\text{\textquotedblleft Solid} + \text{\textquotedblleft Liquid}) \tag{6}$$

In this step the particle size is fixed between 0.3 and 0.6 mm, to determine the effect of temperature. Using the results of the first experiments we have done we have found that the best yields in bio-oils are expected at a temperature equal to 450°C. At this stage we have already determined the main factor which is the temperature, and then it only remains the speed of heating that we vary from 7 to 28°C.min�<sup>1</sup> . So, we take this conclusion in hand and we begin the study by the variation of the speed of heating from 7 to 28°C.min�<sup>1</sup> each time, we calculate the yield of the obtained bio-oil. We deduced that for a heating speed lower than 21°C.min�<sup>1</sup> we have yields of bio-oil less than 52.24% the same thing for speeds higher than 21°C.min�<sup>1</sup> . Finally, we find that the optimal speed for this study is equal to 21°C.min�<sup>1</sup> .

The diameter of the particles is fixed between 0.3 and 0.6 mm. 15 g of rockrose seeds are introduced into the fixed bed reactor and the temperature is changed between 300 and 500°C. The yields of the products of pyrolysis are calculated by the difference between the initial weight and the final weight that constitutes the solid (char) that remains in the reactor, the liquid (HP) that is taken in a graduated test tube, and the percentage of the gas that has escaped in the atmosphere were calculated by the relation of Eq. (6).

#### **3.1 Cistus seeds**
