Methods for scale-up of continuous reactors
A method for scale-up of a micro reactor process from lab to production scale comprises using a wall material for a lab reactor having thermal conductivity ≤3 W/m·K, and using a wall material for a production reactor having thermal conductivity ≥5 W/m·K. Desirably, flow velocity is kept constant, and the height of the production-scale process channel is determined by: H G = 2 × ( A + B λ W + 1 C × ( D h ) ( b - 1 ) ) - 1 h = H G 0 wherein A B and C are constants; H G is the overall volumetric heat transfer coefficient, D h is the hydraulic diameter, λ W is the thermal conductivity of the wall, b is the empirically determined power to which the Reynolds number is raised in the equation for the Nusselt criteria (Nu=a·Re b Pr c ) for the type of flow used, and h is the height of the channel, all in the production-scale process; and H G0 is the overall volumetric heat transfer coefficient in the lab-scale process.
1. A method for a seamless scale-up of a continuous-flow microreactor process, to transfer reactions characterized or developed at a laboratory reactor directly to a pilot or production reactor, with limited or no additional experimentation, the method comprising the steps of:
processing a reaction, in a laboratory reactor using a wall material for the laboratory reactor resulting in a thermal conductivity across the laboratory reactor wall material lower than 3 W/m−K, and afterwards
processing the reaction in a pilot or production reactor using a wall material for the pilot or production reactor resulting in a total thermal conductivity across the pilot or production reactor wall material higher than 5W/m−K,
wherein a fluid velocity in the pilot or production reactor is kept the same as a fluid velocity in the laboratory reactor, and a channel height in the pilot or production reactor is determined, in order to keep volumetric heat transfer properties constant, according to the formula:
H
G
=
2
×
(
A
+
B
λ
W
+
1
C
×
(
D
h
)
(
b
-
1
)
)
-
1
h
=
H
G
0
wherein H G is an overall volumetric heat transfer coefficient in the pilot or production process; A, B, and C are constants; D h is a hydraulic diameter of the channel in the pilot or production reactor; λ W is a thermal conductivity of the wall in the pilot or production reactor; b is an empirically determined power to which the Reynolds number (Re) is raised in the equation for the Nusselt criteria (Nu=a·Re b Pr c ) for the type of flow in the pilot or production reactor; coefficients a and c have empirically determined values; Pr is the Prandtl number; h is the height of the channel in the pilot or production reactor; and H G0 is an overall volumetric heat transfer coefficient in the laboratory reactor.
2. A method for a seamless scale-up of a continuous-flow microreactor process, to transfer reactions characterized or developed at a laboratory reactor directly to a pilot or production reactor, with limited or no additional experimentation, the method comprising the steps of:
processing a reaction, in a laboratory reactor using a wall material for the laboratory reactor resulting in a thermal conductivity across the laboratory reactor wall material lower than 3 W/m−K, and afterwards
processing the reaction in a pilot or production reactor using a wall material for the pilot or production reactor resulting in a total thermal conductivity across the pilot or production reactor wall material higher than 5W/m−K,
wherein a pressure drop and volumetric heat transfer properties in the pilot or production reactor are kept the same as in the laboratory reactor, a channel height and a velocity in the pilot or production reactor being selected as calculated according to the simultaneous solution of the following two formulas:
H
G
=
2
×
(
A
′
+
B
′
λ
W
+
1
C
′
×
Ve
×
(
D
h
)
(
b
-
1
)
)
-
1
h
=
H
G
0
and
Δ
P
=
(
D
′
×
Ve
(
3
+
d
)
D
h
(
1
-
d
)
+
E
′
×
Ve
3
D
h
)
×
2
Ve
0
=
Δ
P
0
wherein H G is an overall volumetric heat transfer coefficient in the pilot or production reactor; A′, B′, and C′ are constants; D h is a hydraulic diameter of the channel in the pilot or production process; λ W is a thermal conductivity of the wall in the pilot or production reactor; Ve is the fluid velocity in the pilot or production reactor; b is an empirically determined power to which the Reynolds (Re) number is raised in the equation for the Nusselt criteria (Nu=a·Re b Pr c ) for the type of flow in the pilot or production reactor; h is the height of the channel in the pilot or production reactor; coefficients a and c have empirically determined values; Pr is the Prandtl number; H G0 is an overall volumetric heat transfer coefficient in the lab-scale reactor; ΔP is a pressure drop of the pilot or production reactor; D′ and E′ are constants; d is a constant; Ve 0 is a fluid velocity of the laboratory reactor; and ΔP 0 is a pressure drop of the laboratory reactor.