CN109704293B - Ignition method of fluidized bed furnace for acid preparation by roasting method - Google Patents
Ignition method of fluidized bed furnace for acid preparation by roasting method Download PDFInfo
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- CN109704293B CN109704293B CN201811556687.1A CN201811556687A CN109704293B CN 109704293 B CN109704293 B CN 109704293B CN 201811556687 A CN201811556687 A CN 201811556687A CN 109704293 B CN109704293 B CN 109704293B
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Abstract
The invention discloses an ignition method of a fluidized bed furnace for preparing acid by a roasting method, which adopts furnace slag or clean furnace slag of a fluidized bed furnace of a pyrite concentrate acid preparation system containing more than 46 percent of sulfur as a raw material of a bedding layer of the fluidized bed furnace, adopts a heat radiation auxiliary heat conduction mode to heat the bedding layer, and intermittently carries out boiling operation of different degrees according to a temperature rise curve, so that the stability and reliability of ignition control of the fluidized bed furnace are greatly improved, the success rate of ignition of the fluidized bed furnace is improved, the normal production time is greatly advanced, meanwhile, the safety of operators and production equipment is ensured, and the production running cost of enterprises can be greatly reduced.
Description
Technical Field
The invention relates to the technical field of chemical production, in particular to an ignition method of a fluidized bed furnace for acid preparation by a roasting method.
Background
The acid production enterprises of the roasting method are all provided with a fluidized bed furnace, and the fluidized bed furnace needs to be heated and ignited after a production device is just built and put into operation or the device is stopped for a long time for maintenance, and the ignition technology of the fluidized bed furnace commonly used at present comprises the following steps: firstly, clean river sand about 600mm is paved at the bottom of a hearth of a boiling furnace, then a natural gas (or fuels such as liquefied gas or diesel oil) fire gun is used for heating the lower position in the middle of the hearth, so that the temperature of the hearth and the temperature of the bedding layer river sand are gradually increased, and an air blower is started to carry out boiling operation on the bedding layer river sand while heating, so that the river sand is uniformly heated in the form of heat conduction and heat convection, and the material feeding production is gradually started after the lowest ignition temperature of the process is reached; and secondly, fine pyrite (or a mixture of pyrite and sulfur or a mixture of pyrite cinder and sulfur) with the thickness of about 600mm is paved at the bottom of a hearth of the fluidized bed furnace, then a natural gas (or fuels such as liquefied gas or diesel oil) fire gun is used for heating at a lower position in the middle of the hearth, so that the temperature of the hearth and the temperature of the pyrite of the bedding layer are gradually raised, and an air blower is started to carry out boiling operation on the pyrite of the bedding layer while heating, so that the pyrite is uniformly heated up in the form of heat conduction and heat convection (the pyrite or sulfur part of the bedding layer starts to be slowly combusted at the later stage of heating up, so that the heating up is accelerated), and the gradual feeding production is started after the lowest ignition temperature of the process is reached. The above methods are all the more common techniques in the ignition control of the fluidized bed furnace for producing acid by a roasting method.
The ignition of the fluidized bed furnace requires that the bedding layer of the fluidized bed furnace can quickly reach the minimum control temperature of process ignition, and the temperature of the bedding layer must be ensured to be uniform as much as possible, so that a foundation is laid for the comprehensive combustion of the raw materials after the materials are fed in the later period. The first ignition technology is characterized in that river sand is uneven in particle size and contains certain moisture, the boiling cannot ensure even temperature distribution, and the air blower is used for carrying out air blowing and boiling, so that the air volume control is too small to cause poor boiling effect, more heat can be taken away by the air volume control, and finer particles are taken out of the room along with air flow, so that great cost waste and environmental pollution are caused, the heating ignition time is greatly prolonged, and the enterprise benefit is influenced. In the second ignition technology, because the laid layer pyrite or sulfur part starts to slowly burn at the later stage of temperature rise, the generated sulfur dioxide, part of sulfur trioxide and fine-grained pyrite can be brought outdoors along with the flue gas, so that environmental pollution and equipment corrosion are caused, and the safety and environmental protection pressure is high; or the flue gas directly enters a system pipeline, so that no environmental pollution exists, but because the flue gas cannot be subjected to dust removal and demisting (combustible gas possibly exists in the flue gas, and explosion risks exist in high-voltage electric fields such as an electric dust remover, an electric demister and the like), dust, fog and the like can be brought to a subsequent conversion section, great influence is caused on a conversion catalyst, the service life of the catalyst is influenced, and even the conversion rate is influenced in severe cases.
Therefore, the two existing ignition technologies have the defects of long temperature rise ignition time, high energy consumption, serious environmental pollution, difficult ignition control and the like, the ignition success rate is not very high, more time is needed to continuously heat by using a heating gun while feeding, serious negative effects are caused to a purification working section and a conversion finished product working section, and meanwhile, the safety, high efficiency, energy conservation and environmental protection production of enterprises are also greatly influenced.
Disclosure of Invention
Aiming at the problems, the invention provides the ignition method of the fluidized bed furnace for preparing acid by the roasting method, which can greatly shorten the temperature rise ignition time of the fluidized bed furnace, reduce the safety and environmental protection pressure, ensure the high efficiency and safety of system operation, and improve the working efficiency, thereby improving the production capacity and the competitive capacity of enterprises and creating more profits.
In order to achieve the purpose, the technical scheme of the invention is as follows:
an ignition method of a fluidized bed furnace for preparing acid by a roasting method comprises the following steps:
step 1: selecting furnace slag or clean slag of a fluidized bed furnace of a pyrite concentrate acid making system containing 46 percent or more of sulfur as a raw material of a bedding layer of the fluidized bed furnace;
step 2: paving a 500-600 mm thick bedding layer raw material above a blast cap at the bottom of the fluidized bed furnace;
and step 3: performing primary cold boiling operation to enable the arrangement of the bedding layer raw materials to be more uniform, and simultaneously performing micro-boiling, middle-boiling and ore feeding air volume boiling tests to enable each control parameter to be more accurate when the micro-boiling, middle-boiling and ore feeding air volume boiling operations are performed subsequently, and sealing a furnace door after the tests are completed;
and 4, step 4: igniting a heating gun to heat and raise the temperature, gradually raising the temperature according to a temperature rise curve of the fluidized bed furnace, and performing micro-boiling operation when the temperature of an air layer at the bottom of a hearth reaches about 500 ℃;
and 5: monitoring the temperature change trend of the 250mm position of the bedding layer, and carrying out middle boiling operation on the bedding layer for 3-5 min once under the condition that the temperature rising rate is reduced, so that the top high-temperature hot slag and the bottom low-temperature slag are boiled and rolled once up and down;
step 6: controlling the temperature of an air layer at the bottom of the hearth to be 650-850 ℃, and controlling the temperature of an air outlet of the hearth to be about 700 ℃;
and 7: continuing to control according to the parameter requirements of the step 6 on the basis of the step 5, and at the moment, rapidly heating the middle low-temperature slag by the bedding slag under the action of the upper and lower high-temperature heat radiation;
and 8: when the temperature of the 250mm position of the bedding layer reaches the lowest reliable ignition temperature of the process, carrying out ore feeding air quantity boiling operation for 2-3 min once, ensuring that the temperature of the bedding layer is uniformly distributed, if the ore feeding air quantity boiling operation is carried out, keeping the temperature of the 250mm position of the bedding layer unchanged or rising, entering the next step, and otherwise, continuously carrying out circulating operation according to the steps 5-8;
and step 9: and completely stopping the heating gun, starting feeding production according to about 80% of the normal production load, switching the purification section to a normal working state after 15min, and then switching to normal production at proper time according to the temperature condition of the boiling furnace.
The sulfur content of the furnace slag discharge or the slag cleaning in the step 1 is less than 0.002%.
The micro-boiling in the step 3 means that about 30 percent of the raw materials of the bedding layer reach a boiling state and the total boiling height is not higher than 100 mm.
The medium boiling in the step 3 means that about 80% of the raw materials of the bedding layer reach a boiling state.
And 3, the ore feeding air volume boiling refers to that 100% of the bedding raw materials reach a boiling state and the total boiling height is about 700 mm.
The time interval for the temperature rise rate reduction in the step 5 is 30min to 60 min.
The process described in step 8 has a minimum reliable ignition temperature of 550 ℃.
Compared with the prior art, the invention has the beneficial effects that:
1. the furnace slag or the clean furnace slag of the fluidized bed furnace of the pyrite concentrate acid making system with over 46 percent of sulfur is used as a raw material of a bedding layer of the fluidized bed furnace, the material not only ensures the uniformity of granularity (no large particles influence the boiling, but also has no small particles which can be discharged out of a room along with flue gas to cause environmental pollution), improves the boiling and temperature rising efficiency, but also has no water, sulfur-containing gas and smoke dust, avoids environmental pollution, and can effectively ensure the safe operation of a conversion catalyst and the like.
2. The heating of the bedding layer is carried out by adopting a heat radiation auxiliary heat conduction mode, under the condition of the same temperature difference, the heat radiation conduction is the difference of the fourth power of the temperature, the heat transfer efficiency is far superior to the heat conduction and heat convection mode adopted by the traditional ignition mode, the heating effect is quite good, the heat utilization rate is very high, and the heating ignition time of the fluidized bed furnace can be shortened by about 50 percent.
3. The boiling operation is carried out intermittently according to the temperature rise curve, generally once in 30-60 min, so that the energy waste phenomenon that heat is carried away by wind, the adverse effects of overlong temperature rise time and the like are avoided, the uniform temperature distribution of the bedding layer can be achieved, and the process control index requirement of ignition is met.
Detailed Description
The present invention will be described in further detail with reference to specific embodiments in order to make the above objects, features and advantages more apparent and understandable.
The invention relates to an ignition method of a fluidized bed furnace for preparing acid by a roasting method, which specifically comprises the following steps:
step 1: according to the specification of an on-site fluidized bed furnace, preparing furnace slag or slag cleaner (containing less than 0.002 percent of sulfur) of the fluidized bed furnace of a pyrite concentrate acid-making system containing 46 percent of sulfur and more as a raw material of a bedding layer of the fluidized bed furnace;
step 2: before planned ignition of the fluidized bed furnace, paving a bedding layer raw material with the thickness of 500-600 mm above a blast cap at the bottom of the fluidized bed furnace under the condition of ensuring that each relevant equipment and facilities are intact and have ignition initial conditions (the raw material dry slag in the step 1);
and step 3: performing primary cold boiling operation to enable the arrangement of the bedding layer raw materials to be more uniform, and simultaneously performing micro-boiling, middle-boiling and ore feeding air volume boiling tests to enable each control parameter to be more accurate when the micro-boiling, middle-boiling and ore feeding air volume boiling operations are performed subsequently, and sealing a furnace door after the tests are completed; wherein, micro-boiling means that about 30 percent of the raw materials of the bedding layer reach a boiling state and the total boiling height is not higher than 100 mm; medium boiling means that about 80% of the raw materials of the bedding layer reach a boiling state; the ore feeding air volume boiling means that 100% of the bedding raw materials reach a boiling state and the total boiling height is about 700 mm;
and 4, step 4: igniting the heating gun to heat under the condition that relevant processes, equipment and the like have conditions again, gradually heating according to a heating curve of the fluidized bed furnace, and performing micro-boiling operation according to the control parameters recorded in the step 3 when the temperature of an air layer at the upper part of the bedding layer at the bottom of the hearth reaches about 500 ℃;
and 5: monitoring the temperature change trend of a fixed layer (the position of about 250mm of a bedding layer), and carrying out middle boiling operation on the bedding layer for 3-5 min under the condition that the temperature rising rate is reduced (generally about 30-60 min), so that the top high-temperature hot slag and the bottom low-temperature slag are boiled and rolled up and down for one time;
step 6: controlling the temperature of an air layer at the bottom of the hearth to be 650-850 ℃, and controlling the temperature of an air outlet of the hearth to be about 700 ℃;
and 7: continuing to control according to the parameter requirements of the step 6 on the basis of the step 5, and at the moment, rapidly heating the middle low-temperature slag by the bedding slag under the action of the upper and lower high-temperature heat radiation;
and 8: monitoring the temperature condition of a fixed layer (the position of a bedding layer about 250 mm), carrying out ore feeding air quantity boiling operation for 2-3 min once after the lowest reliable ignition temperature (550 ℃) of the process is reached, ensuring the temperature distribution of the bedding layer to be uniform, if the ore feeding air quantity boiling operation is carried out, keeping the temperature of the bedding layer 250mm unchanged or rising, completely stopping a heating gun, and otherwise, continuously carrying out circulating operation according to the steps 5, 6, 7 and 8;
and step 9: and completely stopping the heating gun, starting feeding production according to about 80% of the normal production load, switching the purification section to a normal working state after 15min, and then switching to normal production at proper time according to the temperature condition of the boiling furnace.
The nine steps are carried out in sequence, and a complete roasting method for preparing acid by the fluidized bed combustion method is integrally formed, so that the success of one-time ignition of the fluidized bed combustion method can be ensured.
The ignition method of the fluidized bed furnace for acid production by the roasting method greatly improves the one-time ignition success rate of the fluidized bed furnace for acid production by the roasting method, the one-time ignition success rate can reach 100 percent, and production accidents caused by ignition failure are avoided; the heating ignition time of the fluidized bed furnace for acid production by a roasting method is greatly shortened, the energy consumption is reduced, longer time is strived for the advanced normal operation of a production system, and the enterprise benefit is greatly improved; sulfur-containing gas and dust are not generated in the temperature rising process, so that the safety and environmental protection pressure is greatly reduced; the heating gun can be completely stopped in the feeding process, so that a purification system of the acid making process can reliably and safely work, and the damage to a conversion catalyst and the pollution to finished acid are avoided; the utilization rate of heat is effectively improved, low-temperature reliable ignition can be realized, and the increase of production cost caused by energy waste is avoided; the selected bedding layer raw materials have moderate and uniform granularity and are dry, so that the environment pollution and equipment damage caused by the generation of dust and water vapor are avoided, the temperature during ignition can be ensured to be uniform and stable to the maximum extent, and the good guarantee is provided for the normal production after feeding; the method has the advantages of low labor intensity of workers due to the adoption of intermittent boiling, shortened heating ignition time, improved ignition success rate and the like, and is low in investment, simple to operate, convenient to control and especially high in universality; the economic benefit is remarkable, the technology is mature, the application prospect is very wide, the economic cost of an enterprise can be saved by more than 50 ten thousand yuan per year, and the market popularization prospect is very good.
The invention has been successfully applied and practiced for many times in 12 ten thousand tons/year production devices, 20 ten thousand tons/year production devices and 40 ten thousand tons/year production devices of a production system for producing acid from pyrite concentrate containing 46 percent of sulfur, is safe and reliable, has less investment, simple and convenient control, particularly has stronger universality and obvious economic benefit, and is very suitable for popularization.
The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention accordingly, and not to limit the protection scope of the present invention accordingly. All equivalent changes or modifications made in accordance with the spirit of the present disclosure are intended to be covered by the scope of the present disclosure.
Claims (6)
1. An ignition method of a fluidized bed furnace for preparing acid by a roasting method is characterized in that: the method comprises the following steps:
step 1: selecting furnace slag or clean slag of a fluidized bed furnace of a pyrite concentrate acid-making system containing 46% or more of sulfur as a raw material of a bedding layer of the fluidized bed furnace, wherein the sulfur content of the furnace slag or the clean slag is below 0.002%;
step 2: paving a 500-600 mm thick bedding layer raw material above a blast cap at the bottom of the fluidized bed furnace;
and step 3: performing primary cold boiling operation to enable the arrangement of the bedding layer raw materials to be more uniform, and simultaneously performing micro-boiling, middle-boiling and ore feeding air volume boiling tests to enable each control parameter to be more accurate when the micro-boiling, middle-boiling and ore feeding air volume boiling operations are performed subsequently, and sealing a furnace door after the tests are completed;
and 4, step 4: igniting a heating gun to heat and raise the temperature, gradually raising the temperature according to a temperature rise curve of the fluidized bed furnace, and performing micro-boiling operation when the temperature of an air layer at the bottom of a hearth reaches 500 ℃;
and 5: monitoring the temperature change trend of the 250mm position of the bedding layer, and carrying out middle boiling operation on the bedding layer for 3-5 min once under the condition that the temperature rising rate is reduced, so that the top high-temperature hot slag and the bottom low-temperature slag are boiled and rolled once up and down;
step 6: controlling the temperature of an air layer at the bottom of the hearth to be 650-850 ℃, and controlling the temperature of an air outlet of the hearth to be 700 ℃;
and 7: continuing to control according to the parameter requirements of the step 6 on the basis of the step 5, and at the moment, rapidly heating the middle low-temperature slag by the bedding slag under the action of the upper and lower high-temperature heat radiation;
and 8: when the temperature of the 250mm position of the bedding layer reaches the lowest reliable ignition temperature of the process, carrying out ore feeding air quantity boiling operation for 2-3 min once, ensuring that the temperature of the bedding layer is uniformly distributed, if the ore feeding air quantity boiling operation is carried out, keeping the temperature of the 250mm position of the bedding layer unchanged or rising, entering the next step, and otherwise, continuously carrying out circulating operation according to the steps 5-8;
and step 9: and completely stopping the heating gun, starting feeding production according to about 80% of the normal production load, switching the purification section to a normal working state after 15min, and then switching to normal production at proper time according to the temperature condition of the boiling furnace.
2. The ignition method of the fluidized bed furnace for acid production by a roasting method according to claim 1, characterized in that: the micro-boiling in the step 3 means that about 30 percent of the raw materials of the bedding layer reach a boiling state and the total boiling height is not higher than 100 mm.
3. The ignition method of the fluidized bed furnace for acid production by a roasting method according to claim 1, characterized in that: the medium boiling in the step 3 means that about 80% of the raw materials of the bedding layer reach a boiling state.
4. The ignition method of the fluidized bed furnace for acid production by a roasting method according to claim 1, characterized in that: and 3, the ore feeding air volume boiling refers to that 100% of the bedding raw materials reach a boiling state and the total boiling height is about 700 mm.
5. The ignition method of the fluidized bed furnace for acid production by a roasting method according to claim 1, characterized in that: the time interval for the temperature rise rate reduction in the step 5 is 30min to 60 min.
6. The ignition method of the fluidized bed furnace for acid production by a roasting method according to claim 1, characterized in that: the process described in step 8 has a minimum reliable ignition temperature of 550 ℃.
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| CN106379866A (en) * | 2016-08-30 | 2017-02-08 | 襄阳泽东化工集团有限公司 | Energy-saving eco-friendly ignition method of pyrite-based acid making fluidized bed furnace |
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- 2018-12-19 CN CN201811556687.1A patent/CN109704293B/en active Active
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| GB748490A (en) * | 1951-10-24 | 1956-05-02 | Bolidens Gruv Ab | Improvements in and relating to the roasting of pyrites |
| CN102225749A (en) * | 2011-04-27 | 2011-10-26 | 瓮福（集团）有限责任公司 | Start-up method of fluidized bed roaster |
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| CN106379866A (en) * | 2016-08-30 | 2017-02-08 | 襄阳泽东化工集团有限公司 | Energy-saving eco-friendly ignition method of pyrite-based acid making fluidized bed furnace |
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