Dimethyl formylamine solution three-effect rectification recovery method for wet synthesis of leather
Technical field
The present invention relates to a kind of dimethyl formylamine solution three-effect rectification recovery method for wet synthesis of leather.
Background technology
Over past ten years, domestic synthetic leather industry development is swift and violent, and dog-eat-dog makes the product unit profit decline to a great extent.Nearest 2 years, energy scarcity, the price straight line raises up, and energy consumption becomes the principal element of PU leather products production cost, and each manufacturer is just making great efforts the consumption reduction of taping the latent power, and improves the market competitiveness.DMF (dimethyl formamide) is a large amount of solvents that use of PU leather factory, be mainly used in the batching dilution, wait to finish process of setting and soluble in water after, utilize supporting retrieving arrangement that DMF is reclaimed and recycles or sells as byproduct again, about 80% of DMF cost recovery is used for heat energy consumption.
Traditional triple effect DMF occurs since the later stage nineties in last century abroad and reclaim technology, energy-saving effect is obvious, it is energy-conservation at least 30% to reclaim technology than the present domestic economic benefits and social benefits DMF that generally adopts, and domesticly carries out since 04 year that traditional triple effect DMF reclaims the technical study exploitation and industrialization is tested.
Domestic and international traditional triple effect DMF reclaims technology and uses thermal oil or middle pressure steam to be heating agent, adopt air distillation concentrating under reduced pressure technology, and the at present domestic economic benefits and social benefits DMF recovery technology that generally adopts uses low-pressure steam to be heating agent, adopt underpressure distillation normal pressure concentration technique, being transformed into traditional triple effect, to reclaim Technology very difficult.
Summary of the invention
The objective of the invention is to overcome the deficiency of above-mentioned existence, and provide on a kind of basis of reclaiming technology at original economic benefits and social benefits DMF, can cut down the consumption of energy, the dimethyl formylamine solution three-effect rectification recovery method for wet synthesis of leather of save energy.
The objective of the invention is to finish by following technical solution, it comprises: charging, preheating, through upgrading tower and rectifying tower concentrate with separate, discharging and constitute and reclaim technical process, it is characterized in that: it uses low-pressure steam to be heating agent, adopt one-level concentrating under reduced pressure, concentrated, the rectification under vacuum technology of secondary atmospheric, wherein the one-level concentrating under reduced pressure adopts packing tower, secondary atmospheric to concentrate the employing tray column, filler and board-like combination tower are adopted in rectification under vacuum.
Circulation technology is adopted in described recovery technical process, the heat energy of generation at overhead vapours, the heating of tower still, feeding preheating, finished product condensation preheating, rectifying, the recycle between the operation of boiling again.
Gas phase finished product and condensation finished product counter current contact in packing tower are adopted in described recovery technical process, carry out energy, mass transfer, will treat that formic acid condensation of gas among the DMF of extraction becomes liquid separation to the tower still and carry out depickling through the raffinate vaporizer and handle.
The present invention uses for reference traditional triple effect DMF and reclaims Technology, and the economic benefits and social benefits DMF that generally adopts reclaims on the basis of technology at home, by consulting a large amount of domestic and foreign literature reports, calculate through material balance, heat balance scheduling theory, through the research exploratory experiment, economic benefits and social benefits DMF is reclaimed technological transformation become triple effect to reclaim technology, fully utilize original production unit, enhance production capacities, make full use of steam waste heat, reduce steam consumption, have independent intellectual property right, practical, realize production domesticization fully.It promotes the state of the art of PU leather industry for promoting the progress of China PU leather production technology, reduces energy consumption, the offspring that benefits future generations promotes the industry Sustainable development, improves the economic benefit of enterprise, industry, economic benefit and obvious social benefit are of great immediate significance.
The present invention reclaims technology energy-conservation at least 30% than the at present domestic economic benefits and social benefits DMF that generally adopts; The purity that reclaims DMF reaches 99.95%, and moisture content is lower than 500PPm, and acidity is lower than 20PPm, and basicity is lower than 30PPm.
Description of drawings
Fig. 1 is that traditional triple effect DMF reclaims process principle figure.
Fig. 2 is that triple effect DMF of the present invention reclaims process principle figure.
Embodiment
Figure 1 shows that traditional triple effect DMF reclaims process principle figure, it comprises: charging, preheating, through secondary concentrating tower and one-level rectifying tower concentrate with separate, discharging and constitute whole recovery process, it uses thermal oil or middle pressure steam to be heating agent, adopt the air distillation technology, be one-level concentrating under reduced pressure tower C1, second depressurized upgrading tower C2 and atmospheric distillation tower C3, each tower is provided with a reboiler E1, E2, the E3 discharging of boiling again, extracts pure DMF from atmospheric distillation tower C3.
Shown in Figure 2, technical process of the present invention also comprises: charging, preheating, through secondary concentrating tower and one-level rectifying tower concentrate with separate, discharging and constitute whole recovery process; It uses low-pressure steam to be heating agent, adopts one-level concentrating under reduced pressure, concentrated, the rectification under vacuum technology of secondary atmospheric, and wherein the one-level concentrating under reduced pressure adopts packing tower C11, secondary atmospheric to concentrate employing tray column C12, filler and board-like combination tower C13 are adopted in rectification under vacuum.Circulation technology is adopted in above-mentioned recovery technical process, the heat energy of generation at overhead vapours, the heating of tower still, feeding preheating, finished product condensation preheating, rectifying, the recycle between the operation of boiling again.
Gas phase finished product and condensation finished product counter current contact in packing tower are also adopted in recovery technical process of the present invention, carry out energy, mass transfer, will treat that formic acid condensation of gas among the DMF of extraction becomes liquid separation to the tower still and carry out depickling through the raffinate vaporizer and handle.
Economic benefits and social benefits and triple effect retrieving arrangement comparison sheet:
|
Economic benefits and social benefits DMF reclaims |
Triple effect DMF reclaims |
Upgrading tower |
One of normal pressure |
Each one of normal pressure, decompression |
Processing power |
9 tons/hour |
13.5 ton/hour |
Utilization rate of waste heat |
Low |
High |
Steam consumption |
0.97 ton (steam)/ton thin liquid |
0.67 ton (steam)/ton thin liquid |
Electric consumption |
20Kwh/ ton thin liquid |
12Kwh/ ton thin liquid |
Triple effect and traditional triple effect retrieving arrangement comparison sheet:
|
Tradition triple effect DMF reclaims |
Triple effect DMF reclaims |
Upgrading tower |
Reduce pressure two |
Each one of normal pressure, decompression |
Rectifying tower |
Normal pressure |
Decompression |
Original economic benefits and social benefits plant factor |
0 |
80% |
Facility investment |
6,000,000 yuan |
2,000,000 yuan |
Heating agent |
Thermal oil or middle pressure steam |
Low-pressure steam |
The at present domestic economic benefits and social benefits DMF retrieving arrangement more than 100 that has overlaps, but estimates 3.97 hundred million yuan of the new profits in 1 year.