旁路系统介绍

汽轮机旁路

Application 应用

A turbine bypass system permits operation of the boiler independently from the steam turbine during start-up, commissioning, turbine trip (shut down) and load alternations. It gives a higher plant availability and operational flexibility over all different operating conditions. The start-up time under cold, warm and hot conditions superhot is reduced. Keeping the thermal transient in the boiler to a minimum continuous flow through superheater and reheater (maintained tube cooling) must be provided and the pressure during the entire start-up has to be controlled. A turbine bypass system is in operation until desired steam conditions from metal temperatures of rotor and casing of the turbine are matched. This method reduces the solid particle erosion to the turbine also, since the loss of material from the boiler internals most likely occurs during start-up. After a load rejection of the turbine the bypass valves operate the boiler at an optimal standby load and avoid a boiler trip. They equal the difference between the steam generator and the turbine flow. It is a big advantage that commissioning of the boiler can be carried out totally independent of the turbine. Boiler trials that are usual when commissioning the firing system are performed without stressing the turbine unnecessarily.

汽轮机在启动，试运行，运行和调峰运行阶段，旁路系统能够使锅炉独立于汽轮机单独运行。在不同的工艺条件下，它显示了更高的实用性和运转时的灵活及适应性。在冷态，温态,热态和极热的状态下，缩短了系统启动的时间。

维持最小的流量的持续通过过热器和再热器，防止再热器的干烧及冷却其管路,使他们不过热，在整个启动过程中,通过控制压力和温度顺利启动系统。

汽轮机旁路系统的另外一个目的是匹配汽轮机缸体及转子等金属材料与相应的蒸气温度相互适应和匹配. 同时减少在启动阶段锅炉中的金属颗粒对汽轮机的侵蚀与破坏作用.在甩负荷的情况下,实现停机不停炉的目的.

以下待查

当汽轮机出现抑制负载时，旁路的阀门控制锅炉处在一个最理想的备用负载，同样也避免了锅炉跳闸。

它们平衡了蒸汽发电机和汽轮机流动之间的差异。

这是一个大的优点对于汽轮机中的锅炉试运行时能够完全的独立运转。

锅炉的试用在运行不对汽轮机产生不必要的应力的点火系统的试运转中是很平常的。

The HP-bypass valve is sized for 100% steam capacity of the boiler to reduce the pressure

旁路阀门适用于锅炉里100％蒸汽流量。

integrated with desuperheating (PRDS) to cold reheat conditions. It has to protect the live

它保护了正常状况下的蒸汽管道系统。

steam piping system. If there is no reheater the steam has to be conditioned down to

如果没有再热器，蒸汽可以通过旁路阀降低到冷凝器可以接受的状态。

acceptable condenser levels. The valve can operate as an safety valve with the necessary

（当旁路阀门容量大于锅炉出力的70％以上时）阀门可以作为安全阀门运行并必须配有快开快关装置。

fast opening devices. With those fast acting actuators the lifting of the spring loaded safety valves with the associated seat maintenance can be avoided and energy and water keep in

配有快速作用的执行器，可以避免安全阀启动。

the water-steam-circle.

The IP(HRH)/ LP-bypass valves are typically used to divert the steam away from the turbine to 低旁阀门是准确的用于转移蒸汽从汽轮机到冷凝器。

the condenser. They have to protect the reheat piping system. A fast closing device for

它们必须保护再热管道系统。

condenser protection during transient operating periods is also integrated. Due to the radical 一个用于在运行周期的瞬变过程中保护冷凝器的快关装置同时也被安装。

increase in the specific volume of the steam it is often necessary to use a dump tube

由于蒸汽的特殊容量根本的增长，一个作为最后减压的顺流倾斜管道是必需的，它是为了在旁downstream as a final pressure reduction to get a higher backpressure after the bypass valve. 路阀门后得到一个较高的反向压力。

The size of the valve can be minimized.

阀门的尺寸可以减到最小。

In combined heat and power plants bypass valves are required to deliver steam with exact

在电热相结合的工厂里，旁路阀门用于将严格的温度和压力条件下的蒸汽输送到处理工序。temperature and pressure to the process (e.g. paper mills). Because of the different steam

例如造纸厂。因为不同的蒸汽需要从不同数量的高低旁路系统中获得range draws。

demands the range draws from a various number of HP to LP bypass systems. In case of a

back pressure turbine trip the process steam has to be produced over the PRDS.

在反向压力汽轮机跳闸情况中，作用蒸汽是跳过PRDS产生的。

Control concept

控制原理

For normal bypass operation, no extraordinary demands are made on opening and closing

在正常旁路运行中，没有特别的要求对于启动和关闭的时间。

times. The temperature after a HP bypass valve is used as control signal for the spray water 高旁阀门的阀后温度作为控制信号对喷水调节阀进行调节。

control valve. To operate the PRDS as a safety valve at a turbine trip HORA recommends a

在汽轮机跳闸时运行PRDS作为一个安全阀，HORA推荐在控制回到温度传感器之前使

“feed forward” signal before the control goes back to the temperature sensors. This is due to

用“提前给水”的信号。

the loss of control of the spray water valve because it cannot follow the fast opening of the

这是用于解决减温水调节阀失去控制，因为它不能足够精确的随PRDS中的快开装置去保证在PRDS closely enough to keep the downstream temperature within normal operating limits.

正常运行限制中的顺流温度。

Too much unevaporated water or too little water leads to errors in the temperature readings. 太多的未蒸发的减温水或太少的减温水导致在读取温度出现错误。

Therefore at first a heat balance calculation of the steam conditions and the valve position of

所以根据通过温度传感器的控制，在一开始一个对蒸汽条件中的热平衡计算和旁路阀门的阀门

the bypass valve determine the required water amount and related valve position followed by