阅读说明：本技术 一种工业氯化钠废盐的净化处理及资源化再利用方法 (Purification treatment and resource recycling method for industrial sodium chloride waste salt ) 是由 崔咪芬 乔旭 邢佑鑫 刘清 陈献 汤吉海 于 2020-05-26 设计创作，主要内容包括：本发明公开了一种工业氯化钠废盐的净化处理及资源化再利用方法,在空气氛围下,对氯化钠废盐中有机物进行微波热解处理,得到的氯化钠用于生产纯碱,微波热解产生的含有有机杂质的空气进入临氧裂解装置,在催化剂作用下进行催化氧化裂解。本发明利用有机物可以吸收微波而氯化钠盐无法吸收微波的性能,在空气氛围下使微波直接作用于含有机物的氯化钠废盐,使废盐中的有机物吸收微波后自身产生热量从而升高温度,在较短时间内使其自身产生汽化,部分有机物在挥发的同时被氧化,从而使有机物与氯化钠分离,最终使氯化钠得到净化。气化物料进行临氧裂解处理,大大降低了处理能耗和成本。本发明具有处理时间短,效率高,能耗低的特点。(The invention discloses a purification treatment and resource recycling method of industrial sodium chloride waste salt, which comprises the steps of carrying out microwave pyrolysis treatment on organic matters in the sodium chloride waste salt in an air atmosphere to obtain sodium chloride for producing sodium carbonate, and enabling air containing organic impurities generated by microwave pyrolysis to enter an oxygen-critical cracking device to be subjected to catalytic oxidation cracking under the action of a catalyst. The invention utilizes the property that the organic matter can absorb the microwave but the sodium chloride salt can not absorb the microwave, the microwave is directly acted on the sodium chloride waste salt containing the organic matter in the air atmosphere, the organic matter in the waste salt generates heat after absorbing the microwave so as to raise the temperature, the organic matter in the waste salt generates vaporization in a short time, part of the organic matter is oxidized while volatilizing, and thus, the organic matter is separated from the sodium chloride, and finally, the sodium chloride is purified. The gasification material is subjected to the temporary oxygen cracking treatment, so that the treatment energy consumption and cost are greatly reduced. The invention has the characteristics of short processing time, high efficiency and low energy consumption.)

1. A method for purifying and recycling industrial sodium chloride waste salt is characterized in that organic matters in the sodium chloride waste salt are subjected to microwave pyrolysis treatment in the air atmosphere, the obtained sodium chloride is used for producing sodium carbonate, air containing organic impurities generated by microwave pyrolysis enters an oxygen cracking device, and catalytic oxidation cracking treatment is carried out under the action of a catalyst.

2. The method for purification treatment and resource recycling of industrial sodium chloride waste salt according to claim 1, characterized by comprising the following steps:

crushing sodium chloride waste salt, and performing microwave pyrolysis treatment in an air atmosphere;

Preparing saturated solution from sodium chloride subjected to microwave pyrolysis, filtering to remove impurities, and sending into a soda production process;

and (3) introducing the air containing the organic impurities generated by microwave pyrolysis into an oxygen-adjacent cracking device, and carrying out catalytic oxidation cracking treatment under the action of a catalyst.

3. The method for purifying and recycling industrial sodium chloride waste salt according to claim 1 or 2, wherein the sodium chloride content in the sodium chloride waste salt is 90-95%, and the TOC of the waste salt is 10000-30000 mg/kg.

4. The method according to claim 1 or 2, wherein the organic impurities in the waste sodium chloride salt are selected from at least one of benzene, toluene, phenol, catechol, ethylene glycol monomethyl ether, methyl acetate, tert-butanol, and n-butanol.

5. The method for purification treatment and resource recycling of industrial sodium chloride waste salt according to claim 1 or 2, characterized in that the microwave pyrolysis treatment is: the air inlet amount is 5-10 m³/kg_{Salt (salt)}5-10 kg of microwave processing capacity_{Salt (salt)}And h, kW, the temperature is 400-700 ℃, and the time is 20-40 min.

6. The method for purification treatment and resource recycling of industrial sodium chloride waste salt according to claim 1 or 2, wherein the TOC in the sodium chloride after microwave pyrolysis treatment is 0-6 mg/kg.

7. The method for purifying and recycling industrial sodium chloride waste salt according to claim 1 or 2, wherein the catalyst uses alumina as a carrier, CuO as an active component, and the CuO loading is 10-15%.

8. The method for purification treatment and resource recycling of industrial sodium chloride waste salt according to claim 1 or 2, characterized in that the temporary oxygen cracking device is a fixed bed reactor; the catalyst loading was 60% of the fixed bed reactor volume.

9. The method for purifying and recycling industrial sodium chloride waste salt as claimed in claim 1 or 2, wherein the air speed of the air containing organic impurities is 10-20 h^-1(ii) a The temperature of the catalytic oxidation cracking treatment is 250-450 ℃.

10. The method for purification treatment and resource recycling of industrial sodium chloride waste salt according to claim 1 or 2, characterized in that the TOC value in the water at the outlet of the oxygen cracking device is 0-20 mg/L, and the VOC in the discharged waste gas is 0-10 mg/m³。

Technical Field

The invention belongs to the field of environmental protection and chemical waste comprehensive treatment and utilization, relates to a method for purifying and recycling industrial sodium chloride waste salt, and particularly relates to a method for purifying and recycling industrial sodium chloride waste salt containing organic pollutants.

Background

A large amount of byproduct salt slag is generated in the production process of a plurality of chemical products, especially pesticides. According to estimation, the annual production of only the pesticide waste salt in China reaches more than 500 million tons. The waste salt has the characteristics of various types, complex components, high content of toxic and harmful substances, high treatment cost, great environmental hazard and the like. The main component of the waste salt is sodium chloride, and in addition, the waste salt also contains a small amount of water and organic matters which have high toxicity and can form a great threat to the ecological environment and the human health if the waste salt is not properly treated, so that the chemical waste salt belongs to dangerous solid waste. Meanwhile, the waste salt is easy to agglomerate due to moisture, and is not beneficial to be used as a raw material of other corresponding products. On the other hand, sodium chloride is an important strategic resource as an important chemical raw material, and is used as a raw material in many chemical production. Therefore, the industrial waste salt is recycled by using a proper process and equipment as the industrial raw material salt, so that the environmental pollution can be eliminated, the precious salt resources can be fully utilized, the by-products are recycled, and the circular economy is realized.

Due to the overall level of resource utilization and harmless disposal of waste saltLower, the normalization degree is uneven. In the face of increasingly strict environmental protection policies, the treatment and disposal of waste salt become problems to be solved urgently. According to the return after the waste salt disposal, the waste salt disposal means can be classified into sea drainage, landfill and resource utilization. In foreign countries, the salt is directly dumped into the ocean or directly buried after harmless treatment is mostly adopted for treating the waste salt, but the treatment mode has great limitation, high cost and higher requirement on plant sites, and the waste salt is required not to contain toxic inorganic substances. In addition, the method also causes serious waste of sodium chloride resources in the inorganic waste salt. Therefore, resource utilization is the main direction of waste salt treatment. At present, the method for resource utilization of waste salt comprises the following steps: the salt washing method washes salt slag with water or organic solvent to eliminate impurity from salt slag as much as possible, and the treated salt is used in alkali industry. However, the salt washing method has large dosage of salt washing water, the washing water is easy to generate secondary pollution, the retreatment cost is high, and organic impurities in the waste salt are difficult to remove. ② high-temperature treatment method: the salt slag is treated at high temperature, so that organic impurities contained in the salt slag are decomposed into gas at high temperature, the aim of removing the organic impurities is fulfilled, and pure sodium chloride is obtained. For example, CN207222538U discloses that waste salt powder is directly sprayed into an incinerator, where organic matters and decomposable components are decomposed at high temperature, and the organic matters in the waste salt can be well treated. However, sodium chloride melts at 800 ℃ and causes corrosion of equipment and blockage of pipelines, which causes great maintenance pressure on the equipment and has high energy consumption. Furthermore, once Cl in the gas phase at high temperature ^-The concentration of (b) increases, corrosion of the apparatus wall of the post-system is likely to occur. Thirdly, microwave treatment, namely heating and decomposing organic matters and decomposable inorganic salts in the waste salt by a microwave device to obtain usable salts. For example, CN104344407A proposes to treat waste salt by microwave, and the technical key is that the microwave treatment is carried out for more than 100min at 450-500 ℃ in a nitrogen atmosphere, so that organic matters in the waste salt are decomposed and volatilized, and the harmless treatment of the waste salt is realized. But the organic steam generated by microwave analysis is complex to process, the temperature needs to be over 1100 ℃, and the energy consumption and the cost are high. A melting method, CN205659976U discloses a process for treating waste salt by adopting melting, impurity removal and condensationThe method removes organic matters to obtain high-quality salt, but the energy consumption is too high, and the requirement on equipment is higher. The CN107803395A discloses a waste salt treatment process of the carbonization method, but has the disadvantages of high process energy consumption and high equipment requirement.

In summary, the existing industrial waste salt disposal methods still have many disadvantages. The invention aims to solve the problems and provides a technical method for harmlessly treating industrial waste salt and reducing treatment energy consumption, and the technical method is used for recycling the waste salt.

Disclosure of Invention

The invention aims to overcome the defects of the existing waste salt treatment technology and provide a purification treatment and resource recycling method for industrial sodium chloride waste salt, the method combines a microwave cracking treatment method and an adjacent oxygen cracking technology, is suitable for various types of sodium chloride waste salt containing organic impurities, can realize the harmlessness of the waste salt, can send the harmlessness sodium chloride into a soda ash process to carry out resource recycling, and can ensure that the gas containing organic waste gas generated by microwave cracking does not generate secondary pollution in the waste salt treatment process by adopting the adjacent oxygen cracking purification technology.

The purpose of the invention is realized by the following technical scheme:

a purification treatment and resource recycling method for industrial sodium chloride waste salt comprises the following steps: under the air atmosphere, carrying out microwave pyrolysis treatment on organic matters in the sodium chloride waste salt, wherein the obtained sodium chloride is used for producing sodium carbonate, and air containing organic impurities generated by microwave pyrolysis enters an oxygen cracking device and is subjected to catalytic oxidation cracking treatment under the action of a catalyst to realize purification.

The invention relates to a purification treatment and resource recycling method of industrial sodium chloride waste salt, which comprises the following steps:

Crushing sodium chloride waste salt, and performing microwave pyrolysis treatment in an air atmosphere, wherein the microwave pyrolysis temperature is the self-heating temperature generated after the absorption of organic matters in the waste salt;

preparing saturated solution from sodium chloride subjected to microwave pyrolysis, filtering to remove mechanical impurities such as coke and the like, and sending the solution into a soda production process;

and (3) introducing the air containing the organic impurities generated by microwave pyrolysis into an oxygen-adjacent cracking device, and carrying out catalytic oxidation cracking treatment under the action of a catalyst.

The content of sodium chloride in the sodium chloride waste salt is 90% -95%, and the TOC of the waste salt is 10000-30000 mg/kg.

The organic impurities in the sodium chloride waste salt are selected from at least one of benzene, toluene, phenol, catechol, ethylene glycol monomethyl ether, methyl acetate, tert-butanol and n-butanol.

The microwave pyrolysis treatment comprises the following steps: the air inlet amount is 5-10 m³/kg_{Salt (salt)}5-10 kg of microwave processing capacity_{Salt (salt)}And h, kW, the temperature is 400-700 ℃, and the time is 20-40 min. The TOC in the sodium chloride subjected to microwave pyrolysis treatment is 0-6 mg/kg.

The temporary oxygen cracking device can adopt a fixed bed reactor.

The catalyst takes alumina with large specific surface area and relatively strong mechanical strength and high temperature resistance as a carrier, takes CuO as an active component, and has CuO loading capacity of 10-15%. In order to reduce the heat load of the device in the catalytic oxidative cracking process, the catalyst loading is controlled to be 60 percent of the volume of the fixed bed reactor.

The airspeed of the air containing the organic impurities is 10-20 h^-1. The temperature of the catalytic oxidation cracking treatment is 250-450 ℃. After catalytic oxidation cracking treatment, the TOC value in water at the outlet of the oxygen cracking device is 0-20 mg/L, and the VOC in discharged waste gas is 0-10 mg/m³。

The invention has the beneficial effects that:

the invention utilizes the property that the organic matter can absorb the microwave but the sodium chloride salt can not absorb the microwave, the microwave is directly acted on the waste salt containing the organic matter in the air atmosphere, the organic matter in the waste salt generates heat after absorbing the microwave, thereby raising the temperature, vaporizing the organic matter in a short time, oxidizing part of the organic matter while volatilizing, separating the organic matter from the sodium chloride, and finally purifying the sodium chloride. The gasification material is subjected to the temporary oxygen cracking treatment, so that the treatment energy consumption and cost are greatly reduced. The invention has the characteristics of short processing time, high efficiency and low energy consumption.

Drawings

FIG. 1 is a process flow chart of the purification treatment and resource recycling method of industrial sodium chloride waste salt.

Detailed Description

The present invention will be described in further detail below with reference to specific embodiments and with reference to the attached drawings.