Piping system of an auxiliary steam main pipe for boilers

Abstract

Piping system of an auxiliary steam main pipe for boilers, characterized in that the piping system comprises: a boiler body skimming steam connection, a boiler auxiliary steam trunk pipe connection, an economizer skimmer, a manual inlet valve for air preheater auxiliary skimming steam, an electric inlet valve for air preheater auxiliary skimming steam, an inlet valve for air preheater auxiliary skimming steam, an inlet valve for denitrification SCR auxiliary steam, and a steam connection for denitrification SCR, wherein the boiler body skimming steam connection is connected to one end of the electric inlet valve for air preheater auxiliary skimming steam, and wherein the other end of the electric inlet valve for air preheater auxiliary skimming steam is connected to one end of the manual inlet valve for air preheater auxiliary skimming steam, and wherein the other end of the manual inlet valve for air preheater auxiliary skimming steam is connected to one end of the inlet valve for air preheater auxiliary skimming steam, and wherein the other end of the inlet valve for air preheater auxiliary skimming steam is connected to the boiler auxiliary steam trunk pipe connection, and wherein at the junction between the air preheater slagging auxiliary steam inlet valve and the manual air preheater auxiliary slagging steam inlet valve, one end of the denitrification SCR auxiliary steam inlet valve is connected.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of denitrification-SCR of boilers and in particular to a piping system of an auxiliary steam main pipe for boilers. STATE OF THE ART

[0002] Currently, the existing users of the boiler auxiliary steam main pipe include: quenching steam for coal mills, steam for thermal insulation and heat tracing, purge steam for light fuel oil systems, auxiliary steam for SCR denitrification, auxiliary steam for air preheater spreaders, auxiliary steam for coal mill B air preheater, auxiliary steam for the chemical plant, auxiliary steam for flue gas cooler spreaders, auxiliary steam for the urea section, heating steam for electrostatic precipitator hoppers, auxiliary steam for MGGH heating, and flue gas backwash steam for MGGH. During plant operation, the steam for the SCR denitrification dilution air preheater cannot be shut down because it must be continuously running. This means that the boiler auxiliary steam main pipe cannot be isolated for repairs during plant operation. All other users of the auxiliary steam main pipe, however, can be shut down temporarily.

[0003] Currently, SCR steam can only be supplied through the boiler auxiliary steam main pipe. If a leak or other defect occurs in the boiler auxiliary steam main pipe, this leak or defect cannot be isolated and repaired during plant operation. CONTENT OF THE PRESENT UTILITY MODEL

[0004] The purpose of this utility model is to provide a piping system for an auxiliary steam main pipe for boilers that prevents operational disruptions due to leaks in the boiler auxiliary steam main pipe. By using boiler body slag steam to provide SCR steam, SCR steam can be provided even when the auxiliary steam main pipe is shut down, thus preventing operational disruptions due to leaks in the auxiliary steam main pipe.

[0005] The purpose of this utility model can be achieved by the following technical solutions: a piping system of an auxiliary steam main pipe for boilers, comprising: a boiler body skimming steam connection, a boiler auxiliary steam trunk pipe connection, an economizer skimmer, a manual inlet valve for air preheater auxiliary skimming steam, an electric inlet valve for air preheater auxiliary skimming steam, an inlet valve for air preheater auxiliary skimming steam, an inlet valve for denitrification SCR auxiliary steam, and a steam connection for denitrification SCR, wherein the boiler body skimming steam connection is connected to one end of the electric inlet valve for air preheater auxiliary skimming steam, and wherein the other end of the electric inlet valve for air preheater auxiliary skimming steam is connected to one end of the manual inlet valve for air preheater auxiliary skimming steam, and wherein the other end of the manual inlet valve for air preheater auxiliary skimming steam is connected to one end of the inlet valve for air preheater auxiliary skimming steam, and wherein the other end of the inlet valve for air preheater auxiliary skimming steam is connected to the boiler auxiliary steam trunk pipe connection, and wherein at the junction between the air preheater slagging auxiliary steam inlet valve and the manual air preheater auxiliary slagging steam inlet valve, one end of the denitrification SCR auxiliary steam inlet valve is connected.

[0006] Furthermore, the other end of the denitrification-SCR auxiliary steam inlet valve is connected to the denitrification-SCR steam port.

[0007] Furthermore, the diameter of the pipe between the denitrification-SCR auxiliary steam inlet valve and the denitrification-SCR steam connection is smaller than the diameter of the pipe between the boiler body skimming steam connection and the denitrification-SCR auxiliary steam inlet valve.

[0008] Furthermore, the diameter of the pipe between the inlet valve for denitrification-SCR auxiliary steam and the steam connection for denitrification-SCR is DN65.

[0009] Furthermore, the steam pressure at the outlet of the boiler body deslagging steam connection is equal to the steam pressure at the outlet of the boiler auxiliary steam main pipe connection.

[0010] Furthermore, the temperature of the steam at the outlet of the boiler body deslagging steam connection is the temperature of the steam at the outlet of the boiler auxiliary steam main pipe connection.

[0011] Furthermore, the boiler body slag steam connection is connected to one end of the economizer slag collector, with the other end of the economizer slag collector being connected to one end of the electric inlet valve for air preheater auxiliary slag steam.

[0012] Furthermore, one end of the air preheater slag collector is connected to the connection point between the economizer slag collector and the electric inlet valve for air preheater auxiliary slag steam.

[0013] Furthermore, the other end of the air preheater slag collector is connected to the drainage connection for air preheater slag steam.

[0014] Furthermore, the boiler body slagging steam connection is connected to the slagging steam connection for denitrification.

[0015] Compared to the prior art, the present utility model has the following advantageous effects: In the present utility model, the boiler body slag steam is used to provide SCR steam. The source of the SCR steam can be either the boiler body slag steam or the boiler auxiliary steam trunk pipe. Unlike existing systems in which the SCR steam is supplied exclusively via the boiler auxiliary steam trunk pipe, in the present utility model, in the event of a leak in the boiler auxiliary steam trunk pipe, by turning on the electric inlet valve and the manual inlet valve for air preheater slag auxiliary steam and turning off the inlet valve for air preheater slag auxiliary steam, the steam source for the denitrification SCR auxiliary steam inlet valve can be switched from the boiler auxiliary steam trunk pipe to the boiler body slag steam, thus preventing operational disruptions due to leaks in the boiler auxiliary steam trunk pipe. SHORT DESCRIPTION OF THE DRAWING Fig. 1 shows a schematic diagram of a structure of a line of a boiler auxiliary steam trunk pipe of the present utility model; and Fig. 2 shows a schematic representation of a structure of an existing line of a boiler auxiliary steam main pipe. DETAILED DESCRIPTION

[0016] The present utility model is described in detail below with reference to the drawings and specific embodiments. This embodiment is based on the technical concept of the present utility model and depicts detailed embodiments and specific operating sequences. However, the scope of protection of the present utility model is not limited to the following embodiments.

[0017] The current pipe structure of the auxiliary steam main pipe for boilers is in Fig. 2. In Fig. 2, the SCR steam is supplied exclusively through the auxiliary boiler steam main pipe. The problem with this system is that if a leak occurs in the auxiliary boiler steam main pipe, there is no isolation for troubleshooting, leading to operational disruptions.

[0018] The present utility model proposes a piping system of an auxiliary steam trunk pipe for boilers as in Fig. 1. The system includes a boiler body skimming steam connection, a boiler auxiliary steam trunk pipe connection, an economizer skimmer, a manual air preheater auxiliary skimming steam inlet valve, an electric air preheater auxiliary skimming steam inlet valve, an air preheater auxiliary skimming steam inlet valve, a denitrification-SCR auxiliary steam inlet valve, and a denitrification-SCR steam connection.

[0019] The boiler body slag steam connection is connected to one end of the electric inlet valve for air preheater auxiliary slag steam. The other end of the electric inlet valve for air preheater auxiliary slag steam is connected to one end of the manual inlet valve for air preheater auxiliary slag steam. The other end of the manual inlet valve for air preheater auxiliary slag steam is connected to one end of the air preheater auxiliary slag steam inlet valve, while the other end of the air preheater auxiliary slag steam inlet valve is connected to the boiler auxiliary steam main pipe connection.

[0020] At the junction between the air preheater deslagging auxiliary steam inlet valve and the air preheater auxiliary deslagging steam manual inlet valve, one end of the denitrification SCR auxiliary steam inlet valve is connected.

[0021] The other end of the denitrification-SCR auxiliary steam inlet valve is connected to the denitrification-SCR steam port.

[0022] The diameter of the pipe between the denitrification-SCR auxiliary steam inlet valve and the denitrification-SCR steam connection is smaller than the diameter of the pipe between the boiler body skimming steam connection and the denitrification-SCR auxiliary steam inlet valve.

[0023] The diameter of the pipe between the denitrification-SCR auxiliary steam inlet valve and the denitrification-SCR steam connection is DN65.

[0024] The steam pressure at the outlet of the boiler body deslagging steam connection is equal to the steam pressure at the outlet of the boiler auxiliary steam main pipe connection.

[0025] The temperature of the steam at the outlet of the boiler body deslagging steam connection is the temperature of the steam at the outlet of the boiler auxiliary steam main pipe connection.

[0026] The boiler body slag steam connection is connected to one end of the economizer slag collector, and the other end of the economizer slag collector is connected to one end of the air preheater auxiliary slag steam electric inlet valve.

[0027] At the junction point between the economizer slag collector and the electric inlet valve for air preheater auxiliary slag steam, one end of the air preheater slag collector is connected.

[0028] The other end of the air preheater slag collector is connected to the air preheater slag steam drainage port.

[0029] The boiler body skimming steam connection is connected to the skimming steam connection for denitrification.

[0030] In the present utility model, the steam source for the denitrification-SCR auxiliary steam inlet valve can be switched from the boiler auxiliary steam trunk pipe to the boiler body skimming steam by opening the electric inlet valve and the manual air preheater auxiliary skimming steam inlet valve and closing the air preheater auxiliary skimming steam inlet valve.

[0031] The steam source for the boiler auxiliary steam main pipe originates from the secondary low-temperature reheater inlet with nominal parameters of 435 °C and 3.13 MPa. The steam source for the boiler body skimming steam originates from the primary low-temperature reheater inlet with nominal parameters of 431 °C and 10.69 MPa. The temperatures of both steam sources are similar. The steam pressure of the boiler body skimming steam can be reduced to the auxiliary steam pressure by a pressure reducing valve. This allows the steam pressure and temperature of both steam sources to be regulated and thus adapted to the operating conditions.

[0032] The diameter of the denitrification SCR auxiliary steam inlet valve piping is DN65. After piping optimization, all piping from the boiler body slag steam connection to the denitrification SCR auxiliary steam inlet valve has a diameter larger than DN65, indicating that the boiler body slag steam can meet the required denitrification SCR auxiliary steam flow.

[0033] In addition, in the present utility model, the check valve is made of Fig. 2. Due to the dual valve control by the electric and manual inlet valve for air preheater auxiliary skimming steam, backflow is eliminated, resulting in a simplification of the piping.

[0034] The above description presents in detail preferred concrete embodiments of the present utility model. It is understood that those skilled in the art can make numerous modifications and variations based on the concept of this utility model without inventive step. Therefore, all technical solutions that those skilled in the art can derive through logical analysis, deduction, or limited experimentation based on the prior art and the concept of this utility model fall within the scope of protection defined by the patent claims.

Claims

[1] Piping system of an auxiliary steam main pipe for boilers, characterized by that the piping system includes: a boiler body skimming steam connection, a boiler auxiliary steam trunk pipe connection, an economizer skimmer, a manual inlet valve for air preheater auxiliary skimming steam, an electric inlet valve for air preheater auxiliary skimming steam, an inlet valve for air preheater auxiliary skimming steam, an inlet valve for denitrification SCR auxiliary steam, and a steam connection for denitrification SCR, wherein the boiler body skimming steam connection is connected to one end of the electric inlet valve for air preheater auxiliary skimming steam, and wherein the other end of the electric inlet valve for air preheater auxiliary skimming steam is connected to one end of the manual inlet valve for air preheater auxiliary skimming steam, and wherein the other end of the manual inlet valve for air preheater auxiliary skimming steam is connected to one end of the inlet valve for air preheater auxiliary skimming steam, and wherein the other end of the inlet valve for air preheater auxiliary skimming steam is connected to the boiler auxiliary steam trunk pipe connection, and wherein at the junction between the air preheater slagging auxiliary steam inlet valve and the manual air preheater auxiliary slagging steam inlet valve, one end of the denitrification SCR auxiliary steam inlet valve is connected. [2] Auxiliary steam main pipe system for boilers according to claim 1, characterized by that the other end of the denitrification-SCR auxiliary steam inlet valve is connected to the denitrification-SCR steam port. [3] Auxiliary steam main pipe system for boilers according to claim 2, characterized by that the diameter of the pipe between the denitrification-SCR auxiliary steam inlet valve and the denitrification-SCR steam connection is smaller than the diameter of the pipe between the boiler body skimming steam connection and the denitrification-SCR auxiliary steam inlet valve. [4] Auxiliary steam main pipe system for boilers according to claim 3, characterized by that the diameter of the pipe between the denitrification-SCR auxiliary steam inlet valve and the denitrification-SCR steam connection is DN65. [5] Auxiliary steam main pipe system for boilers according to claim 2, characterized bythat the steam pressure at the outlet of the boiler body deslagging steam connection is equal to the steam pressure at the outlet of the boiler auxiliary steam main pipe connection. [6] Auxiliary steam main pipe system for boilers according to claim 5, characterized by that the temperature of the steam at the outlet of the boiler body deslagging steam connection is the temperature of the steam at the outlet of the boiler auxiliary steam trunk pipe connection. [7] Auxiliary steam main pipe system for boilers according to claim 1, characterized by that the boiler body skimming steam connection is connected to one end of the economiser skimmer, the other end of the economiser skimmer being connected to one end of the electric inlet valve for air preheater auxiliary skimming steam. [8] Auxiliary steam main pipe system for boilers according to claim 7, characterized bythat one end of the air preheater slag collector is connected to the connection point between the economiser slag collector and the electric inlet valve for air preheater auxiliary slag steam. [9] Auxiliary steam main pipe system for boilers according to claim 8, characterized by that the other end of the air preheater slag collector is connected to the air preheater slag steam drainage connection. [10] Auxiliary steam main pipe system for boilers according to claim 1, characterized by that the boiler body skimming steam connection is connected to the skimming steam connection for denitrification.

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