Industrial dried sand cyclic heating process for improving efficiency

Abstract

The invention relates to the technical field of industrial drying, and discloses an industrial dried sand cyclic heating process for improving efficiency, which comprises the following steps: carrying out feeding and preheating treatment on wet sand to primarily evaporate surface moisture; carrying out rapid evaporation treatment on the sand grains in a high-temperature area to remove surface moisture; performing constant-temperature drying treatment on the sand grains in a medium-temperature area to remove internal moisture; the sand grains are cooled and shaped in the low-temperature area, and the drying process is completed; moisture is discharged, and heat in the moisture is recycled through a heat energy recycling device; the temperature, the humidity, the airflow speed and heat energy recovery are monitored in real time and dynamically adjusted through the intelligent control system. By means of the multi-stage partition heating and circulating airflow optimization technology, the drying efficiency is greatly improved, and the production period is shortened; heat energy recovery and moisture management are adopted, so that remarkable energy-saving and environment-friendly effects are realized; and intelligent control and uniform heating are combined, so that the drying uniformity of sand grains and the consistency of product quality are ensured, and industrial requirements are met.

Description

Technical Field

[0001] The invention relates to the technical field of industrial drying, in particular to an industrial drying sand circulation heating process for improving efficiency. Background Art

[0002] The drying process of industrial sand is a key link in many industrial fields (such as building materials, casting and chemical industries). In the existing technology, most drying processes use single-zone heating or simple straight-through hot air drying equipment to evaporate and discharge the moisture in the sand through high-temperature hot air.

[0003] The existing technology includes a simple structure of a single high-temperature zone, straight-through airflow and direct moisture discharge. However, the high-temperature treatment in a single area can easily cause uneven drying, with some sand particles being overheated or insufficiently dried, affecting product quality. Second, the thermal energy utilization rate is low, and a large amount of heat is wasted with the discharge of moisture, resulting in high energy consumption. Third, there is a lack of zoning control and dynamic adjustment, and it is impossible to optimize the drying parameters according to changes in the moisture content of the sand particles. The production efficiency is low and it is difficult to meet environmental protection requirements. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides an industrial drying sand circulation heating process for improving efficiency, which solves the problems of low drying efficiency, high energy consumption, uneven drying and lack of environmentally friendly heat energy recovery in the prior art.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: an industrial drying sand circulation heating process for improving efficiency, comprising the following steps:

[0006] Feed and preheat the wet sand to initially evaporate the surface moisture;

[0007] Rapidly evaporate the sand in the high temperature area to remove surface moisture;

[0008] The sand is dried at a constant temperature in the medium temperature zone to remove the internal moisture;

[0009] The sand particles are cooled and shaped in the low temperature zone to complete the drying process;

[0010] Discharge the wet gas and recover the heat in the wet gas through a heat recovery device;

[0011] The temperature, humidity, air flow speed and heat recovery are monitored and adjusted dynamically in real time through the intelligent control system.

[0012] Preferably, the air flow velocity in the high temperature zone is 20-30 m / s, and the temperature range is 120° C.-180° C., so that the rapid evaporation of water on the surface of the sand particles is achieved through the high-speed air flow.

[0013] Preferably, the temperature range of the medium temperature zone is 80° C. to 120° C., the air flow velocity is 1020 m / s, and the hot air direction is optimized by a flow guide device to ensure constant temperature and uniform drying of the sand particles.

[0014] Preferably, the temperature range of the low temperature zone is 30° C. to 60° C., the air flow velocity is 510 m / s, and dehumidified air is used for cooling to prevent the sand particles from absorbing moisture during the cooling process.

[0015] Preferably, the wet gas discharge system includes a wet gas channel, a high-temperature cyclone dust collector and a condenser, which are used to remove sand and dust particles in the exhaust gas and condense the wet gas.

[0016] Preferably, the heat energy recovery device adopts a two-stage heat exchange system to recover high-temperature moisture and medium-temperature moisture respectively, and the heat recovered from the high-temperature moisture is preferentially used for heating the high-temperature zone, and the heat recovered from the medium-temperature moisture is used to preheat fresh air.

[0017] Preferably, the intelligent control system includes a programmable logic controller, a temperature sensor, a humidity sensor and an air flow velocity sensor, and realizes real-time dynamic adjustment of the operating parameters of each area through closed-loop control.

[0018] Preferably, the feeding system includes a vibrating screening device and a conveying system for evenly distributing the wet sand and conveying it to the drying equipment, and the conveying speed is adjustable to meet different processing volume requirements.

[0019] Preferably, the high temperature zone, medium temperature zone and low temperature zone are separated by physical partitions and equipped with heat insulation boards to prevent heat transfer interference and ensure independent operation of each zone.

[0020] Preferably, the air circulation system includes a high-efficiency fan and an adjustable guide plate, and the angle of the guide plate is dynamically adjusted according to the distribution of sand particles and airflow monitoring results to eliminate drying dead corners and improve airflow utilization efficiency.

[0021] The present invention provides an industrial drying sand circulation heating process for improving efficiency.

[0022] Beneficial effects:

[0023] 1. The present invention adopts multi-stage zone heating technology, and adopts a staged drying method of quickly evaporating surface moisture in the high-temperature zone, evenly removing internal moisture in the medium-temperature zone, and cooling and shaping in the low-temperature zone, which significantly improves the drying efficiency. The zone design makes the heating parameters of each stage match the state of the sand particles, avoiding the inefficiency and sand damage caused by high-temperature and long-term drying in a single area. Compared with traditional processes, the drying time is shortened, which greatly improves the controllability and continuity of the production cycle.

[0024] 2. The present invention uses a circulating airflow system and a two-stage heat recovery device. The present invention can efficiently recover the heat in the wet air and reuse it for heating in the high-temperature zone or the medium-temperature zone, greatly reducing the demand for external heat sources and greatly improving the heat recovery efficiency. Compared with traditional processes, energy consumption is greatly reduced. In addition, the exhaust gas emissions meet environmental protection standards after dust removal and condensation treatment, achieving the dual goals of energy saving and environmental protection.

[0025] 3. The present invention ensures that hot air evenly covers the surface of the sand particles through an adjustable diversion system and dynamic air flow speed control, avoiding local over-drying or insufficient drying problems caused by uneven air flow distribution. The zoned heating is combined with the closed-loop feedback mechanism of the intelligent control system to achieve real-time adjustment of temperature, humidity and air flow parameters, ensuring that the moisture content of the sand particles is ultimately stabilized at a constant value, significantly improving the drying uniformity and quality consistency of the sand particles, and meeting the requirements for high-quality dry sand in industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Please refer to the attached Figure 1 The embodiment of the present invention provides an industrial drying sand circulation heating process for improving efficiency. By combining zone heating, circulation airflow optimization, moisture discharge and heat recovery and intelligent control system, the drying efficiency and uniformity of sand particles are significantly improved, while reducing energy consumption and meeting environmental protection requirements. The following is a detailed description of the principle, operation steps and equipment design of the process in combination with the specific implementation method.

[0029] 1. Basic principles of the process

[0030] The core principle of the invention is to divide the drying process of sand into three stages (high temperature rapid evaporation, medium temperature uniform drying, low temperature cooling and shaping), and process the sand in stages through an independently controlled zoned heating system. At the same time, a circulating airflow system is used to achieve multiple utilization of heat energy, and energy consumption is further reduced through moisture discharge and heat recovery devices. The drying parameters are monitored and adjusted in real time through an intelligent control system to ensure that the sand drying process is uniform, efficient and stable.

[0031] 2. Specific implementation steps of the process

[0032] 2.1 Wet sand feeding and preheating

[0033] Feeding system design:

[0034] The wet sand is fed into the drying equipment by a vibrating screening device, which can remove large particles and impurities in the sand and ensure that the wet sand is evenly distributed to avoid accumulation during the subsequent drying process.

[0035] The conveying system adopts high temperature and corrosion resistant chain conveyor or belt conveyor. The conveying speed range is 0.1-0.5m / s. The speed can be adjusted by frequency conversion control to meet different sand processing capacities.

[0036] Warm-up phase:

[0037] The wet sand enters the low-temperature preheating zone (the temperature is set at 30℃~60℃). The preheating zone uses low-temperature hot air to preliminarily heat the sand particles to evaporate part of the surface moisture, avoiding agglomeration or breakage of the sand particles due to rapid evaporation in the subsequent high-temperature zone.

[0038] The hot air flow velocity is 510m / s, and the preheating time is controlled at 25 minutes. The specific time is dynamically adjusted according to the initial humidity of the sand particles.

[0039] 2.2 Rapid evaporation in high temperature area

[0040] Target:

[0041] Rapidly evaporate the moisture on the surface of the sand particles, significantly reduce the surface humidity of the sand particles, and provide conditions for subsequent drying in the medium temperature zone.

[0042] Equipment and parameter design:

[0043] Temperature control: The high temperature zone uses an independent electric heating device, gas heater or steam heat exchanger, and the temperature is set at 120℃~180℃.

[0044] Air flow speed: The high-efficiency fan provides a high-speed air flow of 20 to 30 m / s. The hot air acts on the surface of the sand particles in the form of vortexes to enhance convective heat transfer.

[0045] Optimized airflow: Adjustable airflow guides are set to change the airflow direction to ensure that the hot air evenly covers the sand particles.

[0046] Operation process:

[0047] The wet sand enters the high temperature zone through the conveying system. The conveying speed is controlled at 0.20.3m / s, and the sand stays in the high temperature zone for 58 minutes.

[0048] Temperature and humidity sensors monitor environmental parameters in the high-temperature zone in real time, and the intelligent control system dynamically adjusts heating power and airflow speed based on feedback signals.

[0049] 2.3 Uniform drying in the medium temperature zone

[0050] Target:

[0051] The sand is dried at a constant temperature to remove internal moisture and ensure that the moisture migrates from the core to the surface and evaporates evenly.

[0052] Equipment and parameter design:

[0053] Temperature control: The temperature range of the medium temperature zone is 80℃~120℃, and constant temperature heating is used to ensure the stability of the drying process.

[0054] Air flow speed: The fan provides a medium-speed air flow of 10 to 20 m / s. The air flow direction alternates with the conveying direction to strengthen the contact between the sand surface and the hot air.

[0055] Guide structure: set up multi-point guide devices to optimize hot air distribution and eliminate drying dead corners inside the equipment.

[0056] Operation process:

[0057] The sand enters the medium temperature zone from the high temperature zone, the conveying speed is controlled at 0.10.2m / s, and the sand stays in the medium temperature zone for 1015 minutes.

[0058] The temperature and humidity sensors dynamically monitor the moisture content of the sand particles, and the intelligent control system adjusts the air flow speed and the guide plate angle according to the detection results to avoid excessive or uneven drying of the sand particles.

[0059] 2.4 Cooling and shaping in low temperature zone

[0060] Target:

[0061] The sand is cooled gradually to ensure that the dried sand is stable and prevented from absorbing moisture or clumping.

[0062] Equipment and parameter design:

[0063] Temperature control: The temperature range of the low temperature zone is 30℃~60℃, and low temperature dry air is used for cooling, and the air humidity is controlled below 10%.

[0064] Air flow speed: The fan provides a low-speed air flow of 5 to 10 m / s to prevent sand particles from being washed away or lifted up by the air flow during the cooling process.

[0065] Operation process:

[0066] The sand enters the low temperature zone from the medium temperature zone, the conveying speed is controlled at 0.10.2m / s, and the sand stays in the low temperature zone for 36 minutes.

[0067] The cooled sand is output by the vibrating screening device to storage equipment or subsequent processing.

[0068] 2.5 Wet gas emission and heat recovery

[0069] Moisture emission:

[0070] The wet air is discharged through the wet air discharge channel on the top of the equipment, and a high-temperature cyclone dust collector is installed in the exhaust channel to remove sand and dust particles in the exhaust gas.

[0071] The humidity sensor monitors the exhaust humidity in real time and automatically increases the exhaust frequency when the humidity exceeds the limit.

[0072] Heat recovery:

[0073] The exhaust moisture is recovered through a two-stage heat exchanger:

[0074] Primary heat exchange: heat recovery of high temperature wet air (120℃~150℃) for heating in high temperature area;

[0075] Secondary heat exchange: Heat recovery from medium-temperature humid air (50℃~80℃) is used to preheat fresh air.

[0076] The heat recovery efficiency can reach over 80%, effectively reducing the energy consumption of the equipment.

[0077] 2.6 Intelligent control and closed-loop regulation

[0078] Real-time monitoring:

[0079] Temperature, humidity and air flow velocity sensors are installed inside the drying equipment to monitor the operating parameters of each area in real time.

[0080] Automatic adjustment:

[0081] The intelligent control system controls the heating device, fan and guide device through PLC to achieve dynamic adjustment of temperature, air flow speed and dehumidification frequency.

[0082] Safety assurance:

[0083] The system is equipped with over-temperature alarm, fan fault detection and equipment protection functions to ensure the safe operation of the drying equipment.

[0084] 3. Implementation effect and optimization data

[0085] Through the implementation of the above process, the experimental results are as follows:

[0086] Production capacity: 20-50 tons of sand can be processed per hour;

[0087] Drying time: 20 to 30 minutes;

[0088] Moisture content of sand particles: final moisture content ≤ 0.5%;

[0089] Energy consumption: more than 30% lower than traditional processes;

[0090] Heat recovery rate: ≥80%.

[0091] Example 1

[0092] Process parameters:

[0093] Initial moisture content of wet sand: 20%

[0094] Processing capacity: 20 tons per hour

[0095] High temperature zone temperature: 150℃

[0096] Medium temperature zone temperature: 100℃

[0097] Low temperature zone temperature: 50℃

[0098] Air flow velocity in high temperature area: 25m / s

[0099] Air flow velocity in medium temperature zone: 15m / s

[0100] Air flow velocity in low temperature zone: 8m / s

[0101] Total drying time: 25 minutes

[0102] Moisture emission frequency: once every 10 minutes

[0103] Heat recovery efficiency: 75%

[0104] Implementation steps:

[0105] Feeding and preheating:

[0106] The wet sand is evenly transported through the vibrating screen, the temperature in the preheating zone is controlled at 50°C, the residence time is 5 minutes, and 5% of the moisture on the surface is initially evaporated.

[0107] Rapid evaporation in high temperature area:

[0108] The wet sand enters the high temperature zone, where the temperature is 150°C and the air flow velocity is 25m / s, evaporating 15% of the moisture on the surface of the sand particles.

[0109] Stay time 10 minutes.

[0110] Even drying in the medium temperature zone:

[0111] The sand enters the medium temperature zone, the temperature is 100℃, the air flow velocity is 15m / s, 8% of the internal moisture is evaporated, and the residence time is 8 minutes.

[0112] Cooling and shaping in low temperature zone:

[0113] The sand enters the low temperature zone, where the temperature is 50°C and the air flow velocity is 8m / s, where it is cooled and shaped to prevent moisture absorption, and the residence time is 2 minutes.

[0114] Wet gas discharge and heat recovery:

[0115] The wet gas recovers heat energy through a two-stage heat exchanger, and the recovered heat is used in the high temperature zone and the medium temperature zone.

[0116] Drying results:

[0117] Final moisture content: ≤0.5%

[0118] Reduced energy consumption: 30% lower than traditional processes.

[0119] Example 2

[0120] Process parameters:

[0121] Initial moisture content of wet sand: 25%

[0122] Processing capacity: 30 tons per hour

[0123] High temperature zone temperature: 160℃

[0124] Medium temperature zone temperature: 110℃

[0125] Low temperature zone temperature: 60℃

[0126] Air flow velocity in high temperature zone: 28m / s

[0127] Air flow velocity in medium temperature zone: 18m / s

[0128] Air flow velocity in low temperature zone: 10m / s

[0129] Total drying time: 30 minutes

[0130] Moisture emission frequency: once every 8 minutes

[0131] Heat recovery efficiency: 80%

[0132] Implementation steps:

[0133] Feeding and preheating:

[0134] The wet sand is evenly transported to the drying equipment, the temperature in the preheating zone is controlled at 60°C, the residence time is 5 minutes, and 6% of the moisture on the surface is evaporated.

[0135] Rapid evaporation in high temperature area:

[0136] The wet sand enters the high temperature zone, where the temperature is 160°C, the air flow velocity is 28m / s, and 15% of the moisture on the surface is evaporated.

[0137] The residence time is 12 minutes.

[0138] Even drying in the medium temperature zone:

[0139] The sand enters the medium temperature zone, the temperature is 110℃, the air flow velocity is 18m / s, 9% of the internal moisture is evaporated, and the residence time is 10 minutes.

[0140] Cooling and shaping in low temperature zone:

[0141] The sand enters the low temperature zone, the temperature is 60℃, the air flow speed is 10m / s, it is cooled and shaped, and the residence time is 3 minutes.

[0142] Wet gas discharge and heat recovery:

[0143] The double-stage heat exchanger recovers the heat of the wet gas, with a recovery efficiency of 80%.

[0144] Drying results:

[0145] Final moisture content: ≤0.3%

[0146] Reduced energy consumption: 35% lower than traditional processes.

[0147] Example 3

[0148] Process parameters:

[0149] Initial moisture content of wet sand: 15%

[0150] Processing capacity: 15 tons per hour

[0151] High temperature zone temperature: 140℃

[0152] Medium temperature zone temperature: 90℃

[0153] Low temperature zone temperature: 40℃

[0154] Air flow velocity in high temperature area: 22m / s

[0155] Air flow velocity in medium temperature zone: 12m / s

[0156] Air flow velocity in low temperature zone: 6m / s

[0157] Total drying time: 20 minutes

[0158] Moisture emission frequency: once every 12 minutes

[0159] Heat recovery efficiency: 70%

[0160] Implementation steps:

[0161] Feeding and preheating:

[0162] The wet sand enters the preheating zone through the conveying equipment, the temperature is controlled at 40℃, the residence time is 4 minutes, and 4% of the moisture on the surface is evaporated.

[0163] Rapid evaporation in high temperature area:

[0164] The wet sand enters the high temperature zone, where the temperature is 140°C, the air flow velocity is 22m / s, and 11% of the moisture on the evaporated surface.

[0165] The residence time is 8 minutes.

[0166] Even drying in the medium temperature zone:

[0167] The sand enters the medium temperature zone, the temperature is 90℃, the air flow velocity is 12m / s, 5% of the internal moisture is evaporated, and the residence time is 6 minutes.

[0168] Cooling and shaping in low temperature zone:

[0169] The sand enters the low temperature zone, the temperature is 40℃, the air flow speed is 6m / s, it is cooled and shaped, and the residence time is 2 minutes.

[0170] Wet gas discharge and heat recovery:

[0171] The wet gas recovers heat through the heat exchange device, and the recovered heat is used in the preheating area.

[0172] Drying results:

[0173] Final moisture content: ≤0.5%

[0174] Reduced energy consumption: 25% lower than traditional processes.

[0175] Comparative Example

[0176] Comparative Example 1 (Traditional single temperature zone drying)

[0177] The drying equipment adopts a single temperature zone, the temperature is controlled at 150°C, the air flow velocity is 20m / s, the total drying time is 40 minutes, the moisture is directly discharged, and there is no heat recovery.

[0178] Drying results:

[0179] Final moisture content: 1.5%

[0180] High energy consumption and no heat recovery.

[0181] Comparative Example 2 (no circulating airflow)

[0182] The high temperature zone, medium temperature zone and low temperature zone are separated, but the air flow does not circulate and the moisture is directly discharged.

[0183] Drying results:

[0184] Final moisture content: 0.8%

[0185] The energy consumption reduction is limited.

[0186] Comparative Example 3 (No moisture emission and heat recovery)

[0187] During the drying process, moisture is discharged directly without being treated, resulting in high humidity inside the equipment, affecting the drying effect.

[0188] Drying results:

[0189] Final moisture content: 0.9%

[0190] High energy consumption.

[0191] Comparative experiments and data analysis

[0192] Experimental design:

[0193] Under the conditions of 20% initial moisture content of wet sand and 20 tons of processing capacity per hour, comparative experiments were conducted on Example 1 and Comparative Examples 1, 2, and 3, and the energy consumption, drying time and final moisture content were recorded.

[0194] Data table:

[0195]

[0196] According to the table data, the drying time of Example 1 is shortened to 25 minutes, which is 37.5% shorter than that of Comparative Example 1; the energy consumption of Example 1 is significantly reduced to only 150 kWh, which is 35% less than that of Comparative Example 1; the final moisture content of Example 1 is controlled at ≤0.5%, which is significantly better than 1.5%, 0.8% and 0.9% of the Comparative Examples; Example 1 achieves a heat energy utilization rate of 75% through heat energy recovery, while the Comparative Examples are all 0%.

[0197] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An industrial drying sand circulation heating process for improving efficiency, characterized in that: The following steps are involved: Feed and preheat the wet sand to initially evaporate the surface moisture; Rapidly evaporate the sand in the high temperature area to remove surface moisture; The sand is dried at a constant temperature in the medium temperature zone to remove the internal moisture; The sand particles are cooled and shaped in the low temperature zone to complete the drying process; Discharge the wet gas and recover the heat in the wet gas through a heat recovery device; The temperature, humidity, air flow speed and heat recovery are monitored and adjusted dynamically in real time through the intelligent control system.

2. The industrial drying sand circulation heating process for improving efficiency according to claim 1 is characterized in that: The air flow velocity in the high temperature zone is 20-30 m / s, and the temperature range is 120° C.-180° C., and the rapid evaporation of water on the surface of the sand particles is achieved through the high-speed air flow.

3. The industrial drying sand circulation heating process for improving efficiency according to claim 1 is characterized in that: The temperature range of the medium temperature zone is 80°C to 120°C, the air flow velocity is 1020m / s, and the hot air direction is optimized by the guide device to ensure constant temperature and uniform drying of the sand particles.

4. The industrial drying sand circulation heating process for improving efficiency according to claim 1 is characterized in that: The temperature range of the low temperature zone is 30° C. to 60° C., the air flow velocity is 510 m / s, and dehumidified air is used for cooling to prevent the sand particles from absorbing moisture during the cooling process.

5. The industrial drying sand circulation heating process for improving efficiency according to claim 1 is characterized in that: The wet gas discharge system comprises a wet gas channel, a high-temperature cyclone dust collector and a condenser, which are used to remove sand and dust particles in the exhaust gas and condense the wet gas.

6. The industrial drying sand circulation heating process for improving efficiency according to claim 1 is characterized in that: The heat energy recovery device adopts a two-stage heat exchange system to recover high-temperature moisture and medium-temperature moisture respectively, and the heat recovered from the high-temperature moisture is preferentially used for heating the high-temperature zone, and the heat recovered from the medium-temperature moisture is used to preheat fresh air.

7. The industrial drying sand circulation heating process for improving efficiency according to claim 1 is characterized in that: The intelligent control system includes a programmable logic controller, a temperature sensor, a humidity sensor and an air flow velocity sensor, and realizes real-time dynamic adjustment of the operating parameters of each area through closed-loop control.

8. The industrial drying sand circulation heating process for improving efficiency according to claim 1 is characterized in that: The feeding system includes a vibrating screening device and a conveying system, which are used to evenly distribute the wet sand and convey it to the drying equipment. The conveying speed is adjustable to meet different processing volume requirements.

9. The industrial drying sand circulation heating process for improving efficiency according to claim 1, characterized in that: The high temperature zone, medium temperature zone and low temperature zone are separated by physical partitions and equipped with heat insulation panels to prevent heat transfer interference and ensure independent operation of each area.

10. The industrial drying sand circulation heating process for improving efficiency according to claim 1, characterized in that: The airflow circulation system includes a high-efficiency fan and an adjustable guide plate. The angle of the guide plate is dynamically adjusted according to the distribution of sand particles and airflow monitoring results to eliminate drying dead corners and improve airflow utilization efficiency.

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