MEE Multiple Effect Evaporation System

New technology of black liquid concentration by vapor compressor heating

Description

At present, multi effect evaporation is widely used in pulping alkali recovery evaporation. In the multi effect evaporation system, the more effective the evaporator is, the better the economy is, but the investment cost is also increased simultaneously. According to different requirements of evaporation water, 5-7-effect evaporation system is generally used at present, which has good economy.

In recent years, with the maturity of mechanical vapor recompression (MVR) technology. This technology has been widely used in wastewater treatment (including chemical pulp black liquor, APMP & BCTMP and other chemical mechanical pulp wastewater), food industry, seawater desalination and other fields.

1. MVR Technology

MVR technology is to compress the secondary steam of the evaporator by mechanical method, increase its pressure and temperature, increase its enthalpy, and then send it back to the heating chamber of the evaporator to be used as heating steam, so as to keep the feed liquid in boiling state, while the heating steam itself condenses into water. Compared with the multi effect evaporation technology, MVR technology compresses and recycles all the secondary steam and recovers the latent heat, so it is more energy-saving than the multi effect evaporation technology.

Application of MVR Technology:

When the concentration of evaporated liquid is raised and its boiling point is raised within a certain limit, for example, when the concentration of evaporated black liquid is below 20%, the boiling point is raised no more than 1.5 ℃.

It is used in the areas or enterprises where the electricity price is cheap and the heat energy is expensive.

2. Application of technology in black liquor evaporation of pulp

Taking the evaporation of wheat straw pulp black liquor as an example, the combination evaporation process of MVR technology and multi effect evaporation was compared with the multi effect evaporation process. The details are as follows.

2.1 main parameters and evaporation scheme

The results show that the flow rate of dilute black liquor is 128.6t/h, the temperature of dilute black liquor is 70 ℃, the concentration of dilute black liquor is 10%, the concentration of concentrated black liquor is 45%, and the evaporation water is 100t / h. The multi effect evaporation process is 5-effect evaporation station, and the combined evaporation process is MVR pre concentration + 5-effect evaporation station.

2.2 Operation

The operation of the two evaporation processes for the treatment of wheat straw pulp black liquor is shown in the table.

Operation of two evaporation processes for treating paper pulp black liquor

Note:In operation cost estimation:steam 150rmb/t,electricity 0.6 rmb/kWh,water 0.5rmb/t.

The investment of combined evaporation process equipment increased: evaporator (2500 m2) 375x10000 RMB; MVR compressor 400x10000rmb, total 775x10000 RMB

Annual operating cost reduction of combined evaporation process: 3672-2115 = 1557 (10000RMB)

Investment increase payback period of combined evaporation process: 755 ÷ 1557=0.5year

It can be seen that taking the scale of 100t / h as an example, the combined evaporation process can recover the increased investment in half a year, and save 1557 (10000 RMB) every year in the future, with considerable economic benefits.

Advantages of MVR Technology:

After start-up, there is no need for fresh steam, or a small amount of fresh steam is consumed, so the operation cost is low.

Simple structure, single effect operation, simplify the pipeline, instrument, electrical system.

Easy to start, simple operation, stable operation, less maintenance.

It occupies a small space and has few utilities. In general, there is no need for condenser and cooling tower

Detailed image

Our facility

Jiangsu Hanpu Mechanical Technology Co., Ltd. is a project engineering company jointly established by Jiangsu Zhongyi Environmental Technology Co., Ltd., FERREO A/S in Denmark, Shanghai Jiaotong University and Nanjing Kingreat Machinery Co., Ltd. The company's production base is located in the Huangqiao Industrial Zone of Taixing, covering an area of 300 acres. The companies involved are in the industry of new material, new energy, medicine, chemical, environmental protection, food, and beverage, etc.

The company has a national functional office and facilities as a scientific research bureau. The research center now has 5 doctor tutors, 8 professional engineers, 11 senior engineers, 42 engineers and 68 assistant engineers making it a leading specialized research bureau.

The company has various kinds of general (special) machinery devices including 480 sets and are the most developed working devices in the world such as: Toshiba CNC boring and milling machine imported from Japan, German Schiess CNC turning processing center, CNC fine plasma cutting machine imported from Germany, Laser cutting machine, CNC folding machine, CNC wire cutting and CNC shearing machine, etc.

The company's main projects include but are not limited to: MVR evaporation system, powder washing salt and vacuum salt production project, oil tank sludge cleaning project, landfill leachate treatment project, plant/animal oil processing production line, urban wastewater treatment project, various wastewater treatment projects, and CBD oil extraction production line. Technical support and transfer of API product technology package. The main products are centrifuge series, multi-effect and MVR evaporation and crystallization equipment, laser welding heat transfer board, lithium battery material mixing equipment, pressure vessel and titanium, zirconium, nickel, and other non-standard special equipment.

The company's sales network throughout the whole world, with a domestic sales market share of 50%, and exported to the United States, Canada, Germany, Spain, France, Switzerland, Sweden, Denmark, Australia, Brazil, Argentina, Chile, Colombia, Russia, Ukraine, Poland, Uzbekistan, Indonesia, Vietnam, Singapore, Malaysia, India, Japan, South Korea, Iran, South Africa, Nigeria, and Rwanda.

The company is an internationally competitive engineering company that integrates technical consulting, design, procurement, construction, installation and driving into one, providing engineering EPC general contract, project management, engineering supervision and other comprehensive, full-process services. The company is Committed to be the first and world-renowned technology and technology engineering company in Asia, providing cutting-edge technology and one-stop solutions for the world's industries.