Low-energy treatment of sludge dewatered by municipal centrifuges
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1. Material name: Moisture content of the material: Initial moisture content is around 80%, while the final moisture content is around 30%. Heat source condition: 0.6 MPa saturated water vapor. Material state: The wet material is in a sticky river mud-like form, while the dry material is in a powdery granular form, meeting the owner’s requirements. 2. Analysis of material processing technology: The drying system is an energy-saving technology that makes use of the secondary steam generated by the energy-efficient dryer itself for recycling, thereby reducing the need for external energy sources. As early as the 1960s, Germany and France had successfully applied this technology in fields such as chemicals, food, papermaking, pharmaceuticals, seawater desalination, and wastewater treatment. Its working process involves compressing low-quality steam using a compressor, thereby increasing its temperature and pressure as well as its heat content; the resulting steam then enters the drying system for reuse, so as to make full use of the latent heat of the steam. The exhaust gas can be dust-removed using an exhaust gas cooling absorption tower. 3. Key parameters: Processing capacity per unit: 50–80 tons per day of municipal sludge in wet form; water evaporation capacity per unit: 20–40 tons per day, (i.e., 1–2 tons per hour). All of this water can be reused. Steam consumption per unit: 5-10 tons/day, (i.e., 0.2-0.4 tons/h). Power consumption per unit: 4,000–7,200 kWh/day (i.e., 3–6.0 kWh per (t.h) of sludge). Cost calculation: approximately 40–74 yuan per (t.h) of sludge. Excludes equipment depreciation. The system is equipped with a 2-ton steam boiler. Note: The electricity price is 1.0 yuan per kilowatt-hour, and the steam price is 170 yuan per ton. 4. Description of the process scheme (see the drying process flow diagram for details): 4.1 A new type of energy-saving dryer is used to carry out the drying of municipal sludge as required by the project. This dryer uses steam as the heat source, features high production capacity and low energy consumption, operates in a clean and environmentally friendly environment; its exhaust gases are treated through wet dust removal and washing to ensure emissions meet environmental standards ； 4.2 The core technology lies in making use of the secondary steam and condensed water waste heat generated by the dried exhaust gas; high-pressure fans and Roots compressors are used to increase the pressure and temperature of this waste heat steam before recycling it, thereby **reducing steam consumption. 4.3 During the drying process, an exhaust fan is used in the system to create a closed environment with slight negative pressure ； Fully automated operation, unattended. 4.4 A single set of heat recovery and recycling technology can dry sludge with an 80% moisture content to a moisture level of around 30%, allowing 35.7 tons of recycled water to be obtained per day; over the course of a year, this amounts to nearly 13,000 tons. 4.5 tons of sludge require approximately 6.0 kwh of electricity, with a total cost of around 50–90 yuan per ton (excluding depreciation); the larger the scale, the lower the cost. 4.6 The processing capacity is flexible, with a daily handling capacity of 50=80 tons of sludge per unit. 4.7 Ministry of Investment: Equipment for the daily treatment of 50 tons of municipal sludge; the investment per unit of such equipment is approximately 2–2.8 million yuan. 5. Price list for complete sets of equipment. Serial number, capacity (d/t), quantity (sets), unit price (10,000 yuan). Boiler capacity of the system (t): 1 – 500, 2 – 800, 3 – 2,100, 2 – 4, 3 – 4,112, 0 – 4, 4 – 6, 5 – 6,168, 0 – 4, 10 – 6, 15. Note: The energy consumption per ton of sludge processed is 40–74 yuan.
The low-energy treatment technology for dewatering sludge using municipal centrifuges relies on advanced drying equipment and techniques to effectively remove moisture from the sludge, while meeting the treatment requirements with as low energy consumption as possible. Below are detailed answers and explanations to the information you provided: 1. Material information: – The name of the material is not specifically mentioned; it is generally municipal sludge. - Material moisture content: initial moisture content is about 80%, and final moisture content is about 30%. - Heat source condition: Saturated water vapor at 0.6 MPa is used as the drying heat source. - Material state: The wet material is in a sticky river mud-like form, while the dry material becomes granular, meeting the owner’s usage requirements. 2. Analysis of material handling technologies: – The drying system utilizes energy-saving techniques to reduce energy consumption by efficiently recovering and utilizing the thermal energy of secondary steam. - The technology originated in Germany and France in the 1960s and is applied in various fields. - Low-grade steam is compressed by a compressor to increase its temperature and pressure and raise its enthalpy, after which its latent heat is utilized in a recycling process. - The exhaust gas from the system can be dust-removed using an exhaust gas cooling absorption tower, thereby reducing environmental pollution. 3. Key parameters: - Processing capacity per unit: 50–80 tons of wet sludge per day. - Water evaporation per unit: 20-40 tons of water evaporate per day, which is equivalent to 1-2 tons per hour; the water can be reused. - Steam consumption per unit: 5-10 tons per day, or 0.2-0.4 tons per hour. - Power consumption per unit: 4,000–7,200 kWh per day, which is 3–6 kWh per ton of sludge. - Cost calculation: 40–74 yuan per ton of sludge, excluding equipment depreciation. - The system requires a 2-ton steam boiler. 4. Description of the process scheme: – A new type of energy-saving dryer is used as the core equipment; steam serves as the heat source. Energy efficiency in drying is improved through the recovery and reuse of waste heat from secondary steam and condensate, as well as the use of high-pressure fans and Roots compressors. - The system utilizes micro-negative pressure and fully automated operation to reduce operational costs and enhance safety. - It is possible to recover 35.7 tons of secondary water per day, with an annual recovery volume of nearly 13,000 tons. - Cost-benefit analysis shows that large-scale processing can reduce costs. 5. Investment and price for complete sets of equipment: Based on the requirements for different production capacities, the price list specifies the boiler sizes available for various configurations of equipment and systems, ranging from 50 tons to 540 tons. The investment for a single set of equipment is approximately 2–2.8 million RMB. In summary, this process focuses on energy efficiency and high performance; it employs various technical methods to achieve low-energy treatment of dewatered sludge, which helps reduce operating costs and meets environmental protection requirements. .
I was wondering if there are drying equipment with a smaller processing capacity; our company handles only about 4 tons of sludge per day, and we already have a boiler, so there is no need to purchase another one.