Application field
Background of the project
Acetonitrile is an important organic chemical raw material and is widely used as a solvent or reactant. It is often necessary to separate acetonitrile from water in the process of solvent production or reuse. Due to the azeotrope between acetonitrile and water, the azeotropic point is 76.3°C under normal pressure, and the mass of acetonitrile is 84%, which cannot be achieved by ordinary distillation. The current separation methods are mainly extractive distillation (adding salt), pressure swing rectification and membrane permeation gasification dehydration.
technical comparison
|
name |
Membrane separation |
Pressure swing rectification |
|
Steam (t/t raw material) |
1.2 |
2.5 |
|
Circulating water (m3/t raw material) |
50 |
250 |
|
Low temperature water (m3/t raw material) |
4 |
20 |
|
Chilled water (m3/t raw material) |
5 |
0 |
|
Electricity (kWh/t raw material) |
30 |
20 |
|
Operating cost (yuan/t raw material) |
287 |
580 |
|
Yield (%) |
High, ≥97 |
Low, 90~93 |
|
Number of distillation towers (pieces) |
1 |
2 |
|
Maximum operating pressure (MPa(G)) |
0.2 |
0.3~0.4 |
|
Required steam pressure (MPa(G)) |
≥0.4 |
0.6~0.7 |
|
Operational complexity |
simple, automatic control |
complex, multiplayer |
|
equipment investment |
Relatively high |
Low |
|
Annual operating cost (according to 10m³ per day and 250 days of annual production, that is, 2000 tons/year) |
Energy consumption saving 600,000 yuan; yield improvement saving > 800,000 yuan/year (according to acetonitrile 10,000 yuan/ton), a total saving of more than 1.4 million yuan/year |
|
|
Process selection |
recommend |
Not recommended |
