Agriculture Reference
In-Depth Information
emulsion was varied from 0 to 50% with best results obtained for vinasse concentrations up to
25%. However, when vinasse concentration was increased above 50% they observed that the
flame was unstable.They measured CO as a function of excess air and found that when
concentration of vinasse in the emulsion is increased, CO concentration in the flue gas tend to
stabilize. For emulsions with 20% or higher vinasse content, CO concentration tend to reach a
constant value of about 105 - 110ppm and was almost independent of excess air. They
therefore concluded that the introduction of vinasse makes the complete combustion of #6
fuel oil more difficult due to the possibility of formation of oil-water emulsion.
The Swedish Alpha-Laval reported the economical, technical and commercial feasibility
of 60% solids vinasse combustion using swirl combustion technology [Nilsson, 1981]. In a
later study, Hollandse Constructive group, A Dutch Company reported the complete
combustion of 60% solids vinasse using swirl combustion technology in a specially designed
steam generator [spruytenburg, 1982]. However, detailed technical information on the
combustion of vinasse is still lacking.
Chakrabarty, (1964) observed vigorous foaming during concentration of vinasse from 9%
to 75%. Moreover, concentration of vinasse above 75% solids resulted in crystallisation of
potassium and other salts. As soon as liquid started cooling, pumping was difficult.
The dry solids of vinasse have a minimum calorific value of 6000 BTU/lb (13.9 MJ/kg).
Chakrabarty (1964) incinerated vinasse by spraying in to the top of an incinerator and the ash
thus produced was leached and processed to crystallise potash as KCl and K
2
SO
4
.
Chakrabarty also found that the combustion temperature was much lower than that could be
achieved in a bituminous coal fired boiler and concluded that vinasse was only suitable for a
waste heat boiler to raise low pressure steam.
SAACKE delivered a plant in the 1990s to a German chemical factory for a liquid waste
fuel similar to vinasse. It has 10 SAACKE SSB-burners, each of 1000 kg/h fuel feed with 10
MJ/kg LHV. Optimum combustion and low emissions can be achieved at all loads by proper
split of main and core air. The plant is running with less than 10% support fuel. In 2006
SAACKE installed two more SSB-burners of 26 MW each and one with 30 MW in Brazil, at
two different tube boilers, running with the support of natural gas or fuel oil (max 30%)
[SAACKE, 2009].
Table 5. Shepherd oil distillery Vinasse composition
As received
Dry basis
Solids (%)
29.79
n.a.
Ash (%)
13.31
18.95
Sulphur (%)
0.08
0.12
Volatile matter (%)
48.67
69.31
Fixed carbon (%)
8.24
11.73
Carbon (%)
n.a.
39.72
Hydrogen (%)
n.a.
8.60
Nitrogen (%)
n.a.
1.65
