CN102503785A - Method for recycling fusel in process of producing polyformaldehyde - Google Patents

Abstract

The invention discloses a method for recycling fusel in the process of producing polyformaldehyde. The method comprises the following steps of: (1) adjusting the reflux ratio of a methanol recovery tower to be 1.5 to 1.8 to ensure that the mass percentage of methanol in the recovered fusel is improved to over 70 percent; (2) feeding the raw material methanol and the recovered fusel in an amount which is 15 to 20 mass percent of the raw material methanol into a methanol evaporator, and evaporating to form a gas phase material; and (3) feeding the gas phase material into a formaldehyde reactor, and introducing formaldehyde into the formaldehyde reactor to absorb nitrogen-containing waste gas exhausted from the top of a formaldehyde absorption tower, wherein the flow ratio of the nitrogen-containing waste gas to the gas phase material is controlled to be 1.25 to 1.4. By the method, the content of the formaldehyde is not obviously fluctuated and the content of the methanol and formic acid is not obviously increased after the fusel with the main content of over 70 percent is added, so that the quality of a product prepared by the formaldehyde is not influenced by adding the fusel with the methanol content of over 70 percent.

Description

Fusel recoverying and utilizing method in a kind of polyoxymethylene production process

Technical field

The present invention relates to a kind of fusel recoverying and utilizing method, relate in particular to fusel recoverying and utilizing method in the polyoxymethylene production process.

Background technology

Methanol-water mixed solution and formaldehyde enrichment region methyl alcohol knockout tower after the layering of column overhead water cooler groove gently boiled under-0.05Mpa vacuum in the trioxymethylene district; By cat head (70 ℃ of tower top temperatures) distilled gas phase; Get into and remove pure condensing surface; Phlegma flows into the methanol solution that removes pure tower groove and all delivers to the Methanol Recovery storage tank after getting into and removing pure water cooler cooling, beats to methanol distillation column through the methyl alcohol discharging pump.Use steam heating at the bottom of the Methanol Recovery Tata, the cat head gas-phase methanol is gone into cat head by the reflux pump partial reflux, all the other dischargings to prepared formaldehyde district 60% fusel storage tank through condensing surface and water cooler condensation cooling behind the entering groove.The influence of some component in the fusel (like trioxymethylene, benzene, water etc.) the higher PARA FORMALDEHYDE PRILLS(91,95) preparation feedback of content oxygen temperature is very big, and through trial, 60% fusel that reclaims afterwards can't all add in the reactor drum.Therefore, adopted passive conservative treatment process for remaining fusel in the past: 1. sell at a low price; 2. burning acts as a fuel.3. can add the utilization again of reclaiming methyl alcohol in the prepared formaldehyde reactor drum with 1/10th of material benzenemethanol inlet amount when requiring to reach 60% methanol content on the present former technology, play the effect that reduces production costs.Add according to the prepared formaldehyde reactor drum and can steady running confirm with 1/10th of methanol feeding amount, also do not have this addition of surpassing at present, this is owing to reclaim low decision of fusel master content afterwards.No matter remaining fusel is that cheapness is sold or acted as a fuel, and all makes the methyl alcohol material waste in the jar, and has expended lot of manpower and material resources.Say from the angle of producing, lost material benzenemethanol, increased the cost of producing formaldehyde, say that from the angle of environmental protection the direct burning of some components also can affect for environment.Generally speaking, this passive processing mode is more harm than good, is impracticable from long term growth.

Summary of the invention

The objective of the invention is to overcome the deficiency of prior art, provide a kind of and can fusel recoverying and utilizing method in a kind of polyoxymethylene production process of production cost all recycled, reduced to the fusel that reclaim in the production process.

Fusel recoverying and utilizing method in a kind of polyoxymethylene production process of the present invention, it may further comprise the steps:

(1) reflux ratio of adjustment methanol distillation column is that 1.5-1.8 brings up to more than 70% the quality percentage composition of methyl alcohol in the fusel of recovery;

(2) material benzenemethanol and the fusel that to account for described material benzenemethanol mass percent be the described recovery of 15%-20% are sent into the methanol evaporator evaporation and form gaseous phase materials;

(3) described gaseous phase materials is sent into the formolite reaction device, in described formolite reaction device, feed the nitrogenous waste gas of discharging from the formaldehyde absorbing tower cat head simultaneously, the flow-ratio control of described nitrogenous waste gas and gaseous phase materials is at 1.25-1.4.

The beneficial effect of the inventive method is: the sampling analysis through product index in the PARA FORMALDEHYDE PRILLS(91,95) reactor drum shows; Add become owner of content 70% above fusel after, formaldehyde content is fluctuation not obviously, the content of methyl alcohol, formic acid does not obviously rise yet; The adding of the fusel of methanol content more than 70% does not have influence on the quality product of prepared formaldehyde; Through the recycling of fusel, there are every year 1151 tons of methyl alcohol to utilize again approximately simultaneously, promptly can reclaim the about 3,100,000 yuan material benzenemethanol of market value; Adopt the inventive method can reduce the generation of waste material in a large number, reduce cost, energy-saving and cost-reducing, make rational use of resources.

Embodiment

Be further described in the face of the present invention down.

Fusel recoverying and utilizing method in a kind of polyoxymethylene production process of the present invention, it may further comprise the steps: the reflux ratio of (1) adjustment methanol distillation column is that 1.5-1.8 brings up to more than 70% the quality percentage composition of methyl alcohol in the fusel of recovery; (2) material benzenemethanol and the fusel that to account for described material benzenemethanol mass percent be the described recovery of 15%-20% are sent into the methanol evaporator evaporation and form gaseous phase materials; (3) described gaseous phase materials is sent into the formolite reaction device, in described formolite reaction device, feed the nitrogenous waste gas of discharging from the formaldehyde absorbing tower cat head simultaneously, the flow-ratio control of described nitrogenous waste gas and gaseous phase materials is at 1.25-1.4.

Operating parameterss such as the working pressure of the methanol distillation column in the inventive method, methanol evaporator and formolite reaction device and temperature can adopt existing operating parameters to get final product.

Present method will account for the fusel adding formolite reaction device that the material benzenemethanol mass percent is 15%-20%, simultaneously the flow of nitrogenous waste gas and the gas phase throughput ratio of methyl alcohol will be adjusted into 1.25-1.4, not only keep the stable of quality product, and reduce production cost.

Embodiment 1

(1) reflux ratio of adjustment methanol distillation column is 1.5 to make the quality percentage composition of methyl alcohol in the fusel of recovery bring up to 71.48%; (2) be that the fusel of 15% described recovery is sent into the methanol evaporator evaporation and formed gaseous phase materials with material benzenemethanol with accounting for described material benzenemethanol mass percent; (3) described gaseous phase materials is sent into the formolite reaction device, in described formolite reaction device, feed the nitrogenous waste gas of discharging from the formaldehyde absorbing tower cat head simultaneously, the flow of described nitrogenous waste gas and the throughput ratio of gaseous phase materials are 1.4.

Through detecting: the quality percentage composition of each component is in the fusel: formic acid 0.005%, methyl alcohol 71.48%, trioxymethylene 14.77%, water 2.65%, benzene 2.33%.

Sampling analysis through the product index that takes out in the PARA FORMALDEHYDE PRILLS(91,95) reactor drum shows that after adding fusel, the formolite reaction device is stable, and formaldehyde content is 45.82%, not obviously fluctuation, and the content of methyl alcohol, formic acid does not obviously rise yet.

Embodiment 2

(1) reflux ratio of adjustment methanol distillation column is 1.8 to make the quality percentage composition of methyl alcohol in the fusel of recovery bring up to 70.29%; (2) be that the fusel of 20% described recovery is sent into the methanol evaporator evaporation and formed gaseous phase materials with material benzenemethanol with accounting for described material benzenemethanol mass percent; (3) described gaseous phase materials is sent into the formolite reaction device, in described formolite reaction device, feed the nitrogenous waste gas of discharging from the formaldehyde absorbing tower cat head simultaneously, the flow of described nitrogenous waste gas and the throughput ratio of gaseous phase materials are 1.25.

Through detecting: the quality percentage composition of each component is in the fusel: formic acid 0.003%, methyl alcohol 70.29%, trioxymethylene 7.81%, water 9.24%, benzene 1.9%.

Sampling analysis through the product index that takes out in the PARA FORMALDEHYDE PRILLS(91,95) reactor drum shows that after adding fusel, the formolite reaction device is stable, and formaldehyde content is 44.81%, not obviously fluctuation, and the content of methyl alcohol, formic acid does not obviously rise yet.

Embodiment 3

(1) reflux ratio of adjustment methanol distillation column is 1.5 to make the quality percentage composition of methyl alcohol in the fusel of recovery bring up to 71.35%; (2) be that the fusel of 18% described recovery is sent into the methanol evaporator evaporation and formed gaseous phase materials with material benzenemethanol with accounting for described material benzenemethanol mass percent; (3) described gaseous phase materials is sent into the formolite reaction device, simultaneously, the flow of described nitrogenous waste gas and the throughput ratio of gaseous phase materials are 1.3.

Through detecting: the quality percentage composition of each component is in the fusel: formic acid 0.0032%, methyl alcohol 71.35%, trioxymethylene 9.79 %, water 9.88%, benzene 2.0%.

Sampling analysis through the product index that takes out in the PARA FORMALDEHYDE PRILLS(91,95) reactor drum shows that after adding fusel, the formolite reaction device is stable, and formaldehyde content is 45.58%, not obviously fluctuation, and the content of methyl alcohol, formic acid does not obviously rise yet.

Claims (1)

1. fusel recoverying and utilizing method in the polyoxymethylene production process is characterized in that it may further comprise the steps:

(1) reflux ratio of adjustment methanol distillation column is that 1.5-1.8 brings up to more than 70% the quality percentage composition of methyl alcohol in the fusel of recovery;

(2) material benzenemethanol and the fusel that to account for described material benzenemethanol mass percent be the described recovery of 15%-20% are sent into the methanol evaporator evaporation and form gaseous phase materials;

(3) described gaseous phase materials is sent into the formolite reaction device, in described formolite reaction device, feed the nitrogenous waste gas of discharging from the formaldehyde absorbing tower cat head simultaneously, the flow-ratio control of described nitrogenous waste gas and gaseous phase materials is at 1.25-1.4.