CN111594853A

CN111594853A - Coke inhibitor for hazardous waste incineration kiln

Info

Publication number: CN111594853A
Application number: CN202010361238.2A
Authority: CN
Inventors: 高锦鹏; 李海涛; 姜天凯; 程鹏; 顾向兵; 张海强; 纪秀阳
Original assignee: Shandong Qingbo Ecological Material Integration Utilization Co ltd
Current assignee: Shandong Qingbo Ecological Material Integration Utilization Co ltd
Priority date: 2020-04-30
Filing date: 2020-04-30
Publication date: 2020-08-28

Abstract

The invention relates to the field of hazardous waste incineration disposal, in particular to a coking inhibitor for a hazardous waste incineration kiln. According to the hazardous waste coking principle, calcium hydroxide, calcium carbonate, magnesium oxide, silicon dioxide and aluminum oxide are reasonably proportioned, and after the hazardous waste incinerator is used, the hazardous waste incinerator reacts with low-melting-point materials in the hazardous waste to form high-melting-point materials, the melting point of the materials is improved in a chelating or crystallizing mode with the low-melting-point materials, large net-shaped structures and coke blocks are prevented from being formed, and relevant incineration operation operations are matched (for example, under the condition that fuel and air are effectively mixed, the formation of reducing space around the inner wall of the incinerator is avoided, the coking problem in the rotary kiln can be effectively prevented by reasonably utilizing the aerodynamic force in the incinerator), so that the formation of cokes is inhibited, prevented or reduced, and the operation period of the hazardous.

Description

Coke inhibitor for hazardous waste incineration kiln

Technical Field

The invention relates to the field of hazardous waste incineration disposal, in particular to a coking inhibitor for a hazardous waste incineration kiln.

Background

At present, incineration disposal is still a main way and means for disposing hazardous waste, most hazardous waste can be subjected to capacity reduction disposal through incineration, but coking problems can be caused when industrial hazardous waste is treated by using a rotary kiln. In any type of coking, the formation principle is generated when the industrial hazardous waste is incinerated, specifically, the hazardous waste is decomposed under high temperature, and the generated elements are recombined together to finally form some low-melting-point salt substances.

In general, the waste components generated in industrial processes are relatively complex and contain a large number of salts and other low-melting substances, and these hazardous wastes form a molten and semi-molten state when incinerated. The coking of dangerous waste incineration internal face is a comparatively common phenomenon, and furnace flame central point puts the temperature relatively higher, and fuel ash is mostly the melting form moreover. The slagging phenomenon occurs mainly due to the constituent elements of the ash and the melting point characteristics of the constituents. The industrial waste forms slag after being burned, mainly because of the formation of an ash layer, the increase of the amount of inert gas, the entering of an oxidizing agent into the material and the difficult reaction with combustible materials. The temperature at this time is lower than the temperature at the incineration section, and the next step is to enter the burn-out stage until the residual waste is burnt out. Generally speaking, the temperature of the central position of the burning hearth of the rotary kiln can reach 1100 ℃, and the ash of the fuel is presented in a melting state; the temperature of the surrounding wall smoke is relatively low, and if the ash particles in the smoke still present a sticky or molten state when contacting the wall, the ash particles gradually adhere to the wall of the pipe and form a relatively compact layer of ash.

Nearly all dangerous useless incineration enterprises in China lead to that the start-up cycle all is about one to three months because of the coking problem that produces among the incineration process, and the rare reaches more than 6 months, and the incineration kiln coking needs to stop the maintenance, influences the processing of danger waste material, seriously influences the income and the profit of danger useless processing enterprise to maintenance process cost is high, causes a large amount of fund wastes equally. Coking of an incineration kiln is an industrial problem, and no better solution is provided at present.

At present, researchers at home and abroad begin to pay attention to the problem of coking in a kiln in the incineration process and research the coking mechanism. But no effective solution exists, and the treatment is generally carried out by reducing the compatibility of low-melting-point materials and increasing the temperature of a coking position.

Disclosure of Invention

The invention provides a coking resistant agent for a hazardous waste incineration kiln, which aims at solving the problems in the prior art, and is characterized in that calcium hydroxide, calcium carbonate, magnesium oxide, silicon dioxide and aluminum oxide are reasonably proportioned according to the hazardous waste coking principle, and after the coking resistant agent is used, the mixture reacts with low-melting-point and low-melting-point materials in hazardous waste to form high-melting-point materials, the melting point of the materials is improved in a chelating or crystallizing mode with the low-melting-point materials, and a large net structure and coke blocks are prevented from being formed.

The technical scheme of the invention is that the coking inhibitor for the hazardous waste incineration kiln comprises the following raw material components: calcium hydroxide, calcium carbonate, magnesium oxide, silica and alumina.

Specifically, the mass ratio of calcium hydroxide, magnesium oxide, calcium carbonate, silicon dioxide and aluminum oxide is 30-50: 20-25: 15-20: 10-20: 5-15.

Preferably, the mass ratio of the calcium hydroxide, the magnesium oxide, the calcium carbonate, the silicon dioxide and the aluminum oxide is 40: 20: 15: 10.

The preparation method of the coke inhibitor comprises the following steps: mixing the components together according to a certain proportion.

The application method of the coke inhibitor comprises the following steps: adding a coking inhibitor into the incineration materials in proportion, mechanically stirring uniformly, and then normally feeding the materials into an incineration kiln.

Preferably, 30-100 kg of coke inhibitor is used for each ton of incineration materials, and the specific addition amount is determined by the incineration condition of each hazardous waste incineration unit.

The invention has the beneficial effects that:

hazardous waste is complex in composition, contains fluorine, chlorine, sulfur, phosphorus, metal elements and the like, and is easy to form an acid atmosphere under high-temperature incineration conditions, thereby forming low-melting-point salts.

According to the coking inhibitor for the hazardous waste incineration kiln, the alkaline substance calcium hydroxide is added to neutralize the acidic materials, so that an alkaline environment is provided, the content of acidic gas is reduced, and the reaction generation of low-melting-point materials is inhibited.

By adding calcium-containing materials, the calcium-containing materials can react with sulfur-containing, chlorine-containing and fluorine-containing materials at high temperature to generate calcium salt precipitates, so that the reaction with alkali metals is reduced, the generation of low-melting-point materials is greatly reduced, the low-melting-point materials containing magnesium and aluminum are added to be combined to improve the melting point, the heat and mass transfer coefficient is improved, the temperature difference in the kiln is reduced, and the low-melting-point materials are prevented from being adhered in the kiln. Meanwhile, a silicon-containing material is added to combine with the surface of alkali metal to form a film, so that the metal activity is reduced, and the wall of the reactor is passivated, thereby inhibiting the formation of a coke body.

In conclusion, the invention makes full use of the way that the high-melting-point material reacts with the low-melting-point material in the incineration material to form the high-melting-point material, chelates with the low-melting-point material or crystallizes, improves the melting point of the material, prevents the formation of a large net structure, forms coke blocks, and is matched with related incineration operation, thereby inhibiting, preventing or reducing the formation of the coke and greatly improving the operation period of the hazardous waste incinerator. The overhaul cost investment is reduced, and direct economic benefits are brought to hazardous waste disposal enterprises.

Detailed Description

The present invention will be described in further detail with reference to the following examples, but it should not be construed that the scope of the above subject matter is limited to the following examples. All the technologies realized based on the above contents of the present invention belong to the scope of the present invention. Except as otherwise noted, the following examples were carried out using conventional techniques.

The coke inhibitor prepared by the method of the invention has the following embodiments 1-3, and the specific proportions by weight are as follows:

TABLE 1 Material proportioning Table

The components of examples 1-3 were mixed together in proportions to give the scorch retarders of examples 1-3.

Test examples

The test object is a mixture of dangerous waste materials such as distillation residues, kettle residues, oil sludge and the like generated in the pesticide industry, the medicine industry, the oil refining industry and the like, indexes of different batches of materials are different, and the detection indexes of the materials in each group in the test are as follows:

material 1: the calorific value is 4000kcal/kg, the sulfur content is 1.5%, the chlorine content is 1.4%, the fluorine content is 0.05%, the phosphorus content is 0.2%, and the total amount of alkali metal is 0.2%.

Material 2: 3600kcal/kg of heat value, 2.1 percent of sulfur content, 1.8 percent of chlorine content, 0.1 percent of fluorine content, 0.5 percent of phosphorus content and 0.4 percent of total alkali metal content.

Material 3: the calorific value was 4500kcal/kg, the sulfur content was 3.1%, the chlorine content was 2.1%, the fluorine content was 0.3%, the phosphorus content was 0.6%, and the total alkali metal content was 0.5%.

The experimental method comprises the following steps: the experimental group respectively adds the coke inhibitor of the embodiment 1-3 into the compatible materials, after the materials are uniformly stirred, the normal feeding materials enter a pilot-scale rotary kiln through a feeding system (the pilot-scale rotary kiln is usually 3.5 meters, the inner diameter is 0.6 meter, the daily treatment capacity is 2 tons), the incineration temperature is set to be 700-plus-800 ℃, the retention time is 1 hour, the incineration environment is simulated for testing, and the coking condition of the kiln tail is regularly observed. Operating cycle judgment standard: and judging whether the kiln tail is coked or not according to the ring formation and ridge formation of the kiln tail and the flow state phenomenon of the kiln tail material, and ending the experiment if the kiln tail is coked. In the experiment, the control group was prepared without adding the scorch retarder, and the other conditions were the same.

The effect of adding various coke inhibitors on the coke rate and the oil sample composition was compared as follows 1, 2, 3:

as can be seen from the above tables 2, 3 and 4, the operation cycle of the rotary kiln added with the coke inhibitor of the examples 1-3 is significantly higher than that of the control group without the coke inhibitor, and it can be seen that the coke inhibitor is added into the hazardous waste materials to effectively inhibit, prevent or reduce the formation of coked materials, thereby greatly improving the operation cycle of the hazardous waste incinerator. The investment of maintenance cost is reduced, and direct economic benefits are brought to hazardous waste disposal enterprises.

Claims

1. The coke inhibitor for the hazardous waste incineration kiln is characterized by comprising the following raw materials: calcium hydroxide, calcium carbonate, magnesium oxide, silica and alumina.

2. The coke inhibitor for the hazardous waste incineration kiln of claim 1, wherein the mass ratio of the calcium hydroxide, the magnesium oxide, the calcium carbonate, the silicon dioxide and the aluminum oxide is 30-50: 20-25: 15-20: 10-20: 5-15.

3. The coke inhibitor for the hazardous waste incineration kiln of claim 2, wherein the mass ratio of the calcium hydroxide, the magnesium oxide, the calcium carbonate, the silicon dioxide and the aluminum oxide is 40: 20: 15: 10.

4. The coke inhibitor for the hazardous waste incineration kiln according to claim 1, characterized in that the preparation method of the coke inhibitor is to mix the components together according to a certain proportion.

5. The method for using the coke inhibitor for the hazardous waste incineration kiln as claimed in claim 1, wherein the coke inhibitor is added into the incineration materials in proportion, mechanically stirred uniformly and then fed into the incineration kiln normally.

6. The use method of the coke inhibitor for the hazardous waste incineration kiln according to claim 5, wherein 30-100 kg of coke inhibitor is used per ton of incineration material.