7.0 CONTROL ELEMENT

 

Assumptions made:

• Constant holdup in Pyrolysis Reactor (V constant)

• Density of feed and A are constant

• T3 = T (Outlet temperature is the temperature of the reactor)

• wCi = wC (Condenser element)

 

Material flow rates, both solid and gas phase, together with the reactor temperature control the key parameters of heating rate, peak temperature, residence time of solids and contact time between solid and gas phases. These factors affect the product distribution and the product properties. 

 

Gas flow rate through the reactor affects the contact time between primary vapours and hot char and so affects the degree of secondary char formation. Low flows favour char yield and are preferred for slow pyrolysis; high gas flows are used in fast pyrolysis, effectively stripping off the vapours as soon as they are formed. 

 

Any factor of pyrolysis conditions that increases the contact between primary vapours and hot char, including low gas flow or slow heating is likely to favour char formation at the expense of liquid yield, while a low temperature is controlled throughout the reaction.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1)  To control the temperature of outflow

 

Fix a condenser that transfers heat into the reactor. The heat must be optimum for slow pyrolysis so biochar production is more favoured in the reaction. Temperature of outflow must be controlled to 350°C in order for slow pyrolysis to take place.
 

Type of controller: PID controller

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2) To control the level of production of Bio-Oil

 

Install a control valve at the burner to reduce heating rate, enabling slow pyrolysis that favours production of biochar.
Type of controller: PID controller