阅读说明：本技术 一种连续制备预氧毡的方法 (Method for continuously preparing pre-oxidized felt ) 是由 陈新华 袁豪雄 李凯 于 2019-10-28 设计创作，主要内容包括：本发明公开了一种连续制备预氧毡的方法,步骤包括A、低温处理：将原材料输送至低温炉膛内,热风循环,同时通入水蒸气和雾化助剂,开始低温环化反应；B、中温处理：将原材料输送至中温炉膛内,热风循环,同时通入水蒸气和雾化助剂,完成初步环化反应；C、高温处理：将原材料输送至高温炉膛内,热风循环,原材料快速通过,实现原材料的预氧化。该方法优点在于不仅在生产效率上提高2-3倍,同时热风循环伴随水蒸气增加热穿透、雾化助剂提高了反应速率,避免了纤维毡内部反应放热引起着火的风险；同时得到的聚丙烯腈预氧毡纤维的强度提高20-30％,预氧毡内部纤维与表面纤维强度均衡、预氧化程度适中。(The invention discloses a method for continuously preparing a pre-oxidized felt, which comprises the following steps: conveying the raw materials into a low-temperature hearth, circulating hot air, introducing steam and an atomization aid simultaneously, and starting a low-temperature cyclization reaction; B. intermediate temperature treatment: conveying the raw materials into a medium-temperature hearth, circulating hot air, and introducing steam and an atomization aid simultaneously to complete a preliminary cyclization reaction; C. high-temperature treatment: the raw materials are conveyed into a high-temperature hearth, hot air circulates, the raw materials rapidly pass through, and pre-oxidation of the raw materials is realized. The method has the advantages that the production efficiency is improved by 2-3 times, meanwhile, the hot air circulation is accompanied by the increase of the heat penetration of the water vapor, the atomization aid improves the reaction rate, and the risk of ignition caused by the heat release of the reaction in the fibrofelt is avoided; meanwhile, the strength of the obtained polyacrylonitrile pre-oxidized felt fiber is improved by 20-30%, the strength of the internal fiber and the surface fiber of the pre-oxidized felt are balanced, and the pre-oxidation degree is moderate.)

1. A method for continuously preparing a pre-oxidized felt is characterized by comprising the following steps: comprises the steps of

A. Low-temperature treatment: conveying the raw materials into a low-temperature hearth, circulating hot air, introducing steam and an atomization aid simultaneously, and starting a low-temperature cyclization reaction;

B. intermediate temperature treatment: conveying the raw materials into a medium-temperature hearth, circulating hot air, introducing water vapor and an atomization aid simultaneously to complete a preliminary cyclization reaction, and completing oxygen bridge construction of the raw materials to realize basic non-melting and non-combustion;

C. high-temperature treatment: the raw materials are conveyed into a high-temperature hearth, hot air circulates, the raw materials rapidly pass through, and pre-oxidation of the raw materials is realized.

2. The method for continuously preparing the pre-oxidized felt according to claim 1, characterized in that: the temperature in the low-temperature hearth is 185-205 ℃, the treatment time is 60-360min, the wind speed of hot air circulation is 0.5-4m/s, and the wind flow is 1000-8000m³The water vapor flow is 100-³The flow rate of the atomization auxiliary agent is 0.1-20m³/h。

3. A continuous process for the preparation of pre-oxygen according to claim 1A method of felting characterized by: the temperature in the medium-temperature hearth is between 205 ℃ and 230 ℃, the treatment time is between 60 and 480min, the wind speed of hot air circulation is between 0.5 and 4m/s, and the wind flow is between 1000 ℃ and 12000m³The water vapor flow is 200-³The flow rate of the atomization auxiliary agent is 0.1-20m³/h。

4. The method for continuously preparing the pre-oxidized felt according to claim 1, characterized in that: the temperature in the high-temperature hearth is 235-250 ℃, the treatment time is 30-120min, the wind speed of hot air circulation is 1-6m/s, and the wind flow is 3000-15000m³/h。

5. The method for continuously preparing the pre-oxidized felt according to claim 1, characterized in that: the atomization aid is one or a mixture of acetic acid, urea, a potassium permanganate solution, dilute hydrochloric acid and an aniline solution, and the diameter of the atomization aid is 0.2-100 um.

6. The method for continuously preparing the pre-oxidized felt according to claim 1, characterized in that: the hot air sweeps the upper and lower surfaces of the raw material simultaneously, and the included angle between the sweeping direction and the plane of the raw material is 15-75 degrees.

7. The method for continuously preparing the pre-oxidized felt according to claim 1, characterized in that: the thickness of the raw material is 4-25mm, and the density of the raw material is 0.06-0.16g/cm³。

8. The method for continuously preparing the pre-oxidized felt according to claim 1, characterized in that: the raw material is conveyed by a mesh belt or a carrier roller.

Technical Field

The invention relates to the technical field of pre-oxidized felt preparation, in particular to a method for continuously preparing a pre-oxidized felt.

Background

Along with the development of economy, the demand of electric power is also getting bigger and bigger, and although traditional thermal power generation can satisfy the demand of electric power, the electricity generation is accompanied with a large amount of dust pollution simultaneously. With the improvement of the requirement on environmental protection, thermal power generation is gradually replaced by novel solar power generation and wind power generation as pollution-free power generation modes, and particularly, the solar power generation gradually comes into the market and is accepted by people.

The production temperature of a single crystal furnace and a polycrystalline ingot furnace which are special equipment for solar power generation is high, energy consumption is one of important reasons for increasing the cost, and the carbon fiber composite material has good heat preservation performance at high temperature, and meanwhile, the product has high purity and does not pollute production raw materials; along with the increase of the demand of the market photovoltaic market, the demand of the carbon fiber heat preservation felt is also increased continuously, the preparation of the pre-oxidized felt is an intermediate process for producing the carbon fiber heat preservation material, and the quality of the polyacrylonitrile pre-oxidized felt directly determines the quality of the carbon fiber heat preservation felt.

Disclosure of Invention

The invention aims to provide a method for continuously preparing a pre-oxidized felt, which solves the problems that polyacrylonitrile cannot be continuously prepared in the prior art, fire is easily generated in the pre-oxidation process, and the produced polyacrylonitrile pre-oxidized felt has poor performance, insufficient oxidation, hair falling and wrinkling and the like.

The invention realizes the purpose through the following technical scheme:

a method for continuously preparing a pre-oxidized felt comprises the following steps

A. Low-temperature treatment: conveying the raw materials into a low-temperature hearth, circulating hot air, introducing steam and an atomization aid, and improving hot air penetrability under the action of the steam and taking away reaction heat generated by internal reaction of fibers in time; the atomization auxiliary agent directly acts on the surface of the internal fiber of the raw material through hot air/water vapor, so that the integral cyclization temperature of the raw material is widened, and low-temperature cyclization reaction is started at low temperature;

B. intermediate temperature treatment: conveying the raw materials into a medium-temperature hearth, circulating hot air, and introducing steam and an atomization aid simultaneously to complete a preliminary cyclization reaction; the reaction temperature is increased at a lower temperature section, so that the reaction time is effectively reduced, the basic cyclization reaction of the raw materials is realized in a short time, and the oxygen bridge is built to realize non-melting and non-combustion;

C. high-temperature treatment: the raw materials are conveyed into a high-temperature hearth, hot air circulates, the raw materials pass through the hearth quickly, and the raw materials which are subjected to medium-temperature treatment are further subjected to high-temperature quick treatment to realize pre-oxidation of the raw materials.

The further improvement is that the temperature in the low-temperature hearth is 185-205 ℃, the treatment time is 60-360min, the wind speed of hot air circulation is 0.5-4m/s, and the wind flow is 1000-8000m³The water vapor flow is 100-³The flow rate of the atomization auxiliary agent is 0.1-20m³/h。

The further improvement is that the temperature in the medium temperature hearth is 205-230 ℃, the treatment time is 60-480min, the wind speed of hot air circulation is 0.5-4m/s, and the wind flow is 1000-12000m³The water vapor flow is 200-³The flow rate of the atomization auxiliary agent is 0.1-20m³/h。

The further improvement is that the temperature in the high-temperature hearth is 235-15000 m, the treatment time is 30-120min, the wind speed of hot air circulation is 1-6m/s, and the wind flow is 3000-15000m³/h。

The further improvement is that the atomization aid is one or a mixture of acetic acid, urea, a potassium permanganate solution, dilute hydrochloric acid and an aniline solution, and the diameter of the atomization aid is 0.2-100 um.

The further improvement is that the hot air simultaneously sweeps the upper surface and the lower surface of the raw material, and the sweeping direction forms an included angle of 15-75 degrees with the plane of the raw material.

The further improvement is that the thickness of the raw material is 4-25mm, and the density of the raw material is 0.06-0.16g/cm³。

The further improvement is that the conveying mode of the raw materials is mesh belt conveying or roller conveying.

The invention has the beneficial effects that:

(1) in the production aspect: the continuous preparation of the polyacrylonitrile pre-oxidized felt is realized, the raw material is ensured to be flat in the whole production process by adopting a mesh belt or a carrier roller, and the obtained pre-oxidized felt product has no folds; the production efficiency is greatly improved by 2-3 times;

(2) the process aspect is as follows: the hot air is adopted to carry the steam and the atomization aid, so that the hot air penetrability is improved, the reaction heat of the raw materials is prevented from remaining in the interior, the possibility of ignition is greatly reduced, and the stable operation of the process is ensured; the introduction of the atomization aid can generate cyclization reaction in the oxidation process at a lower temperature, the reaction speed is increased in the medium-temperature stage to complete preliminary oxidation shaping, and the final high-temperature rapid treatment ensures sufficient oxidation;

(3) performance aspects: the quality of the polyacrylonitrile pre-oxidized felt is improved, the fiber strength is improved by 20-30%, the strength of the fibers in the pre-oxidized felt and the surface fibers is balanced, and the pre-oxidation degree is moderate.

Drawings

FIG. 1 is a flow chart of the method of the present invention.

Detailed Description

The present application is described in further detail below with reference to examples, and it should be noted that the following detailed description is provided for further explanation of the present application and should not be construed as limiting the scope of the present application, and that certain insubstantial modifications and adaptations of the present application may be made by those skilled in the art based on the above-mentioned disclosure.

As shown in figure 1, a method for continuously preparing pre-oxidized felt uses raw materials with thickness of 4-25mm and density of 0.06-0.16g/cm³And the conveying is carried out by adopting a mesh belt or a carrier roller, and the method comprises the following specific steps:

A. low-temperature treatment: the raw material is conveyed into a low-temperature hearth with the temperature of 185-205 ℃, the hot air is circulated, the wind speed of the hot air circulation is 0.5-4m/s, and the wind flow is 1000-8000m³H, simultaneously introducing water vapor and an atomization aid (the atomization aid is selected and has a diameter of 0.2-100um, the same applies below), wherein the flow rate of the water vapor is 100-³The flow rate of the atomization auxiliary agent is 0.1-20m³Adjusting the angle of an upper air deflector and a lower air deflector in the hearth to be 15-75 degrees, ensuring that hot air carrying steam and an atomization aid directly sweeps the upper surface and the lower surface of the raw material, and ensuring that the treatment time is 60-360min according to the length of a low-temperature section furnace body; the hot air penetrability is improved under the action of the water vapor, and the reaction heat generated by the internal reaction of the fiber is taken away in time; the atomization auxiliary agent directly acts on the surface of the internal fiber of the raw material through hot air/water vapor, so that the integral cyclization temperature of the raw material is widened, and low-temperature cyclization reaction is started at low temperature;

B. at medium temperatureProcessing: the raw material is conveyed into a medium-temperature hearth with the temperature of 205-230 ℃, the hot air is circulated, the wind speed of the hot air circulation is 0.5-4m/s, and the wind flow is 12000m³H, simultaneously introducing water vapor and an atomization aid, wherein the flow rate of the water vapor is 200-1000m³The flow rate of the atomization auxiliary agent is 0.1-20m³Finishing the preliminary cyclization reaction, adjusting the angle of an upper air deflector and a lower air deflector in a hearth to be 15-75 degrees, ensuring that hot air carrying steam and an atomization aid directly sweeps the upper surface and the lower surface of the raw material, and ensuring that the treatment time is 60-360min according to the length of a furnace body in a medium-temperature section; the reaction temperature is increased at a lower temperature section, so that the reaction time is effectively reduced, the basic cyclization reaction of the raw materials is realized in a short time, and the oxygen bridge is built to realize non-melting and non-combustion;

C. high-temperature treatment: conveying the raw material into a high-temperature hearth with the temperature of 235-250 ℃, circulating hot air, wherein the wind speed of the hot air circulation is 1-6m/s, and the wind flow is 3000-15000m³H, quickly passing the raw materials, adjusting the angle of an upper air deflector and a lower air deflector in the hearth to be 15-75 degrees, ensuring that hot air carrying steam and an atomization aid directly sweeps the upper surface and the lower surface of the raw materials, and ensuring that the treatment time is 30-120min according to the length of a furnace body in a high-temperature section; further, the raw materials which are treated at medium temperature are quickly treated at high temperature, so that the pre-oxidation of the raw materials is realized.