Design, selection and energy saving of dairy pump
In dairy industry production, the selection of advanced and reasonable mechanical equipment is of great significance to ensure product quality, reduce operation and maintenance costs, improve the competitiveness of dairy products and economic benefits, and promote the development of dairy industry and technological progress. In terms of liquid milk, the selection of aseptic filling equipment and technology is particularly prominent, but there are also problems of equipment selection to reduce operating costs.
The design of falling-film evaporator and the selection of traditional falling-film evaporator is to achieve the purpose of energy saving and consumption reduction by increasing the utilization times of steam (single effect to multiple effect). However, the increase of the efficiency doubles the steel consumption and the cost. Due to the limitation of heat transfer temperature difference, the increase of the efficiency is usually no more than seven effects. Double-effect falling-film evaporator with steam jet heat pump and hydraulic ejector is the design of common falling-film evaporator.
The application of heat pump in falling film evaporator adopts mechanical thermal compression type heat pump compressor which can be centrifugal and positive displacement compressor. Compression temperature difference is large, generally around 11℃, which limits the use of mechanical compression heat pump efficiency is generally no more than three effects, and the evaporation of the solution with a higher boiling point is limited, and the structure is complex, high cost, high maintenance cost, large power consumption, so the mechanical compression heat pump application is very few.
Steam jet type heat pump is adopted. The shape of steam jet type heat pump is like inner tube, without transmission device, with simple structure and more applications. With and without a heat pump can be equivalent to an increase in efficiency. Adopt inter-wall condenser and water ring vacuum pump with heat pump, coil condenser and water ring vacuum pump condenser as material preheater to make full use of heat of final effect secondary steam and reduce the consumption of cooling water. In this type of multi-effect falling-film evaporator, the final secondary steam condenses into water of the same temperature (only producing phase change) and then is discharged from the condenser. The condensed water has a high temperature and is soft and can be used well. Water ring vacuum pump will evaporator non-condensable gas and a small amount of steam suction back into the atmosphere. And maintain the effect of evaporation have a certain degree of vacuum. Compared with the use of hydraulic injectors, cooling water consumption and power consumption are lower. Take the rich bright dairy group two models RNJM02-2400 type double falling film evaporator as an example, the evaporation capacity of 2400 kg/h, form a complete set of water ring vacuum pump motor power is 5.5 kw, cooling water consumption of 9 t/h, water temperature l0 ℃, discharge temperature 38 ℃, with ability to hydraulic ejector double-effect falling film evaporator, power 13.5 kw, saving water 13 tons per hour. According to the water supply price of 1.00 yuan/ton and drainage price of 0.80 yuan/ton, electricity and water can reduce the operating cost of 143,391 yuan a year, and recover all the equipment investment in three years.
Structure of shell and tube condenser and water ring vacuum pump adopts the mixed condenser, cold water tower, water ring vacuum pump with heat pump, material preheater, mixed condenser, cold water tower and water ring vacuum pump three-way falling film evaporator, the cooling water circulation cooling water pump will be sent to the water tower, cooling water temperature by 8 ℃, in the calculation of the majority of the evaporator generally take 6 ℃. The pressure of cooling water circulating pump is not high, as long as the cooling circulating water is sent to the cooling tower, during the working process, only cooling water needs to be recycled through the cooling tower, almost no need to add low-temperature cold water, water saving effect is particularly significant, especially in the area of water shortage.
Supporting multiple effect evaporator pump selection we use single mechanical seal of pump, I have been chosen jiangsu jingjiang fluoroplastic alloy pump valve factory, jilin successfully using matsubara pharmaceutical factory production of vitamin C food industry company, the main purpose is to solve the vitamin C to the corrosion resistance of the special requirement of the pump, then successfully applied in three-way RNJM03-5000 type falling film evaporator, and applications in Long Dan group and hailaer bright dairy company, the effect has been very good. But this fluoroplastic alloy pump is only the mechanical seal of the water supply removed, and matching motor power and previously selected pump little change. Later, ICB series single-end mechanical seal stainless plate stamping pump of wuxi jiyang pump company was selected, which was also used for rnjm02-2400 double-effect falling film evaporator. The feed pump model icb50-25-200, flow 6.3m3/h, head 32m, motor power 2.2kw. The other two material pumps and one condensing pump were selected as icb32-25-125, flow 3.2t/h, head 20m, motor power 0.55kw. The total power of the unit of rn-jm02-2400 double-effect falling film evaporator is reduced by 6.75kw only by the centrifugal pump, which is calculated by 300 days per year and 16 hours per day (two shifts), saving 32400 yuan per year. Tianxi jiuyang ICB series pump is used in Harbin oil factory.
In the spray drying system, only the exhaust fan is used instead of the fan. In heilongjiang daqing dairy factory, there are four sets of centrifugal spray drying units, which are designed in this way. Take rglp-500 drying unit as an example. According to the traditional design, the model of the inlet fan is 4-72-12no8c, with air volume 20100m3/h, wind pressure 2445Pa and motor power of 30kw, which can save electricity cost of 144,000 yuan per year.
Reasonable choice of high pressure pump. The working pressure of high-pressure pump is generally 14MPa, and the general selection of 25MPa high-pressure pump. Traffic selection as long as meet the needs. High pressure pump factory, motor power is designed according to the rated pressure and flow rate, and the working pressure is far less than the rated pressure of the pump, so in the work flow, under the pressure of power is smaller than its rated output power is very much, if choose a motor power to meet the need of the work output power motor to match, can reduce the total power of the drying system, reduce the operation cost. Heilongjiang yi ‘an dairy is doing this. Model rpyp03-500 drying unit, the traditional high-pressure pump model is gjb1-25, with supporting motor power of 7.5kw, while yi ‘an dairy products factory USES the same type of high-pressure pump, and the success rate of supporting motor replacement is 5.5kw, which can save 10,000 yuan of electricity cost per year and keep good operation.
The traditional spray drying unit with reasonable structure is cloth bag powder, which is divided into first cyclone powder and second cloth bag powder. If the first stage powder is chosen as a cyclone, the second stage is also a cyclone, and the exhaust fan USES two, the air volume of the first stage exhaust fan is larger, the wind pressure is lower, the air volume of the second stage exhaust fan is smaller, and the wind pressure is higher, the total power of the two exhaust machines is the same as that of the traditional one. Compared with the traditional choice of a exhaust fan, the size of the cyclone separator of two-stage powder dusting becomes smaller, which saves the stainless steel material, reduces the investment, and is convenient to arrange.
Reasonable use of heat energy with exhaust air to preheat the air, and then use heated steam to heat the condensed water of air to preheat the air, make full use of waste heat, so as to achieve the purpose of energy saving and consumption reduction.