At present, the paper machine dryer Department of steam system is divided into three sections of steam, heat pump heating two basic types. The three sections of the steam belongs to the passive steam series heating system is the new steam with the control valve decompression dryer cylinder pressure required for the high temperature, low temperature dryer also uses steam valve to make up for the pressure regulator Steam, wasted steam energy grade and quantity; heat pump heating belongs to the active steam parallel heating system, drying section in the paper machine dryer set heat pump, paper machine dryer temperature curve set heat pump steam pressure. The new steam and paper machine dryer steam level difference produced by the effective energy into the work of the heat pump, but when the paper machine operating conditions change, heat pump into the new ISl steam valve opening will be reduced, resulting in steam Effective loss, reduce heat pump efficiency. This topic will be adjustable heat pump heating system for the paper machine drying department, thereby increasing the paper machine dryer heat pump heating system adjustment range, to ensure that the dryer pressure and drying cylinder exhaust pressure difference, recovery of secondary steam , Reducing the condensing water discharge temperature, increasing the surface temperature of the dryer and the partial pressure of water vapor on the web surface, and playing the role of enhancing heat transfer and mass transfer during the drying of the web. 1 steam jet heat pump 1.1 heat pump working principle Paper machine dryer heat pump using steam jet heat pump (also known as steam compressor). Steam jet heat pump power plant or boiler using steam supply steam pressure and dryer steam pressure difference between the energy into heat pump power. The working fluid is sucked in through the nozzle 1 in the receiving chamber 2, and the working fluid and the introduced low-pressure fluid are mixed and exchanged in the mixing chamber 3, gradually filling the entire section to establish a uniform velocity field The flow rate of the compressed mixed fluid in the diffuser 4 is decreased and the pressure of the mixed fluid is increased to the steam supply pressure required by the heat consumer. 1.2 Classification of heat pump Steam injection heat pump heating system must be based on thermal parameters of the user to adjust the operating conditions. Steam jet heat pump control by regulation, can be divided into two types of quality control and flow control. (1) steam quality adjustment heat pump (also known as non-adjustable heat pump). Regulating valve is installed on the working steam main pipe of the non-adjustable heat pump. The heat pump itself is not equipped with regulating device. When the paper machine running condition changes for the steam pressure and the flow rate, the regulating valve on the working steam inlet pipe of the heat pump needs to be adjusted . During the adjustment process, the change of the opening of the steam regulating valve will change the working steam pressure entering the heat pump, so as to change the ability of the new steam of the heat pump to import work. Especially when the paper machine steam load decreases, the steam control valve opening decreases, the actual supply of new heat pump inlet steam pressure decreases, resulting in heat pump inlet steam and heat pump outlet steam pressure decreases, heat pump work ability to reduce work efficiency decline. (2) steam flow adjustment heat pump (also known as adjustable heat pump). Adjustable heat pump inlet steam pipe without the need to set the control valve, the heat pump itself to set the implementing agencies, such as valve positioner. Adjustable heat pump paper machine operating conditions in the adjustment process, just adjust the nozzle cross-sectional area, the new heat pump inlet steam pressure unchanged, the unit capacity of steam does not change the new power, paper machine operating conditions in a variety of operating conditions Under the heat pump can maintain efficient operation. 2 adjustable heat pump heating system actual production and operation 2.1 paper machine technical parameters The following Chibi Chenwoo Paper Co., Ltd. 2640mm paper machine (production Shuangjiao Zhi) as an example for analysis. Paper machine steam supplied by the plant thermoelectric power station, respectively, pressure 0.85,0.5 MPa, the use of mechanical backwater steam condensate back to the thermal power station. The paper machine is equipped with a glue machine, there are 31 drying cylinders before sizing, 10 drying cylinders after the glue machine, 2 cold cylinders, open steam hood, paper machine Main technical parameters: paper width 2640 mm ; Drying cylinder diameter 1500 mm; mesh width 3100 mm; product quantity 60-80m2; sizing method for double sizing; nominal capacity lOOt / d. 2.2 heat pump heat pump heat pump configuration paper machine dryer temperature rise curve requirements, the glue dryer dryer section is divided into low-temperature section, the temperature section and the high temperature section, the glue dryer dryer section is divided into medium temperature Section and high temperature section. Adjustable heat pump 101a, lOlb for sizing front and rear high temperature dryer, adjustable heat pump 102 is set for the dryer in the middle temperature section, the dryer pressure in the dryer section is stable, so the ordinary heat pump 103 is used. The steam system uses 0.85MPa high-grade steam as the working steam of the adjustable heat pump to control the drain pressure difference of the dryer. 0.50MPa low-grade steam used to control the temperature in the middle and high temperature section of the dryer pressure and the amount of steam is not enough, at the same time, as the heat pump 103 working steam. Steam condensate water system in each section of the dryer cylinder water separation tank without pump residual pressure self-flow back to the end of the condensate tank is not set through the steam pipe closed steam condensate system. Non-condensable gas generated by the discharge of this paper machine heat pump heating system has set a perfect non-condensable gas discharge system to improve the dryer heat transfer coefficient. 2.3 adjustable heat pump heating system operation The paper machine in the dryer with adjustable heat pump heating system, the control system uses interlock optimization control to meet the quantitative requirements of large changes, easy operation, stable operation, product output And the quality is obviously improved. The characteristics are as follows: (1) Adjustable heat pump adapts to the quantitative change of paper machine. Analyzing the experimental data, it can be found that the adjustable heat pump heating system adapts to the change of paper machine operating conditions. When the paper machine product quantitative increase, production increases, the various sections of the dryer into the steam pressure, intake steam and dryer drain pressure are reliably guaranteed. Drum exhaust blow steam and secondary steam all recycled, condensate tank gauge pressure is zero. (2) Paper machine speed and output significantly improved Before the technology transformation, the paper machine dryer with non-adjustable heat pump heating system, before and after the transformation of the same quantitative product paper machine speed and output changes compared to the paper machine that uses Adjustable heat pump heating system, the production of 70 m2 production increased 1.12 times, production of 100 g / m2 products increased 1.24 times. (3) The pressure of dryer steam is reduced and the pressure difference of dryer drain is increased. The data shows that with adjustable heat pump instead of non-adjustable heat pump, when the paper machine reaches the same speed and output, Tank pressure decreases, dryer drain pressure will increase. (4) Taking full advantage of the steam effective calculation, the effective steam pressure of the saturated steam is 0.85MPa and 0.30MPa respectively, and the effective efficiencies are 842.39 and 718.10 kJ / kg respectively. If the steam pressure of 0.85MPa is decompressed to 0.30MPa, the effective loss will be 124.49 kJ / kg, accounting for 14.8% of the effective steam of new steam. The use of adjustable heat pump heating system with the traditional three-stage steam system compared to steam energy quality and quantity have been used properly. 3 Drying Unit Effective Area Average Drying Strength Drying Unit Effective Area Drying strength refers to the paper machine with the maximum capacity of the dryer configuration parameters, the correct access to this data for the existing paper machine to determine the number of dryer changes, As well as the economic and rational allocation of paper machine equipment are very important, the relevant literature and experimental data at home and abroad are not many, at present, the average unit area of ​​the average drying strength of the domestic double-sided paper machine dryer unit is usually about 20 ks / (m2 • h) , Partial to conservative. Drying effective area of ​​the average drying strength is calculated as follows: m = QG / F Where: m is the drying intensity, ks / (m2 • h); G is the amount of papermaking, kg / h; Q is the amount of dehydration, kg paper; F for dryer effective area, m2. The paper machine dryer with adjustable heat pump heating system production 70,90,100,120 g / m2 products, according to the running speed of the paper machine and papermaking volume, the calculated average effective area drying dryer average strength. The paper machine adopts open air hood and simple bag ventilation. The experimental data shows that the drying intensity of the dryer reaches 40 ks / (m2 • h) or more. The comparison of the data shows that the adjustable heat pump heating system is adopted to increase the paper machine speed, Adding production and economically justifying the drying cylinder creates the preconditions. 4 Conclusion The traditional three sections of steam heating method will result in the steam efficient waste; using a non-adjustable heat pump heating system, when the paper machine running speed, product changes, only the method of adjusting the new steam pressure to meet the paper The drying process requires that the opening of the working steam regulating valve is reduced to force the steam pressure into the heat pump to decrease so as to reduce the workability of the heat pump. The adjustable heat pump heating system is used for producing the drying section of various product paper machines, The utility model can make full use of the effective energy of the new steam, give full play to the power of high-grade steam, improve the heat transfer and mass transfer effects of the dryer, overcome the shortcomings and deficiencies of the traditional three-stage steam-supply system and the conventional non-adjustable heat pump thermal system, The use of steam heat energy grade and quantity, significantly improve paper machine speed, increase production, improve quality and reduce steam consumption.