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Industry Standard of the People's Republic of China
20521-92
Design Regulations for Chemical Steam Systems
1992-08-10
1992-12-01
Ministry of Chemical Industry of the People's Republic of China
Industry Standard of the People's Republic of China
Design Regulations for Chemical Steam Systems
HG/T 20521-92
Editor: The Eighth Design Institute of the Ministry of Chemical Industry
Approving Department: Ministry of Chemical Industry
Editing Center of Engineering Construction Standards of the Ministry of Chemical Industry
Document of the Ministry of Chemical Industry
Chemical Foundation [19921620]
Notice on the Release of the Chemical Industry Standard "Design Regulations for Chemical Steam Systems"
To the Chemical Industry Departments (bureaus, companies) of all provinces, autonomous regions, municipalities directly under the Central Government, and cities with independent planning status, and all relevant design units:
The "Design Regulations for Chemical Steam Systems" compiled by the Eighth Design Institute of the Ministry of Chemical Industry has been reviewed and approved as a recommended chemical industry standard, numbered HG/T20521-92. It will be implemented from December 1, 1992. This regulation is managed by the Thermal Engineering Design Technology Center of the Ministry of Chemical Industry; and published and distributed by the Engineering Construction Standards Editing Center of the Ministry. If you have any questions or comments during the implementation process, please inform the Thermal Engineering Design Technology Center of the Ministry.
Ministry of Chemical Industry
August 10, 1992
General Provisions
System types and scales
System composition,
System formulation
Project list
Selection of major equipment in the system··
System control
Principles of waste heat utilization
System optimization and comparison
Appendix A
Heat consumption data table and coal consumption of heating system
Appendix Appendix B
Appendix C
Appendix D
Condition table
Steam balance diagram
Terms of this Regulation
Articles
（2）
（3）
（4）
This Regulation is formulated to implement the national energy conservation policy, reduce the total energy consumption of the steam system, 1.0.1
improve the design level of the steam system, and make the system safe and reliable, flexible in operation, technologically advanced, and economically reasonable.
1.0.2 This Regulation is applicable to the design of steam systems for new, rebuilt, and expanded projects in the chemical industry with a maximum steam load of 60t/h or above. It can also be used as a reference for the design of small regional cogeneration projects. bzxz.net
1.0.3 The type, scale and parameters of the steam system are determined based on the steam load, parameters and the machines driven by the steam turbine (such as centrifugal compressors, blowers, centrifugal pumps and generators, etc., hereinafter referred to as machine pump power).
1.0.4 If there is any conflict between this regulation and the national standard, the national standard shall prevail. 2
General provisions
2.0.1 Based on the design conditions of process steam load, parameters, steam engine pumps and by-product steam, combined with the parameters of my country's power equipment, the system parameters are determined after technical and economic comparison.
2.0.2 Based on the steam balance calculation, select and determine the steam used in the system. The capacity of boilers and operating boilers.
2.0.3 According to the requirements of steam balance, determine the type, parameters, and capacity of the turbine driving the pump in the system and calculate its steam consumption. 2.0.4 According to the economic and reasonable needs of the steam system of the chemical enterprise, determine the methods and ways of utilizing waste heat in the process unit.
2.0.5 According to the possible production situation of the process unit, conduct a comprehensive design of the steam system's regulation and control, safe venting, and the setting of ancillary equipment. 2.0.6 According to the needs and possibilities of the chemical enterprise's steam system, determine the recovery and utilization methods of the system's steam condensate.
3 System type and scale
System type Type
3.1.1 Pure heating system: This system is used when combined heat and power (electricity) production cannot be implemented. Its characteristics are heat supply only, no steam drive, simple system, insufficient utilization of thermal energy, high energy consumption, and generally used for small or low-pressure systems
3.1.2' Combined heat and power (electricity) production system: The heating steam is mainly supplied by the steam turbine that drives the pump and exhausts steam. The thermal energy is fully utilized and the energy consumption is low. 3.1.3 System with gas turbine: The gas turbine drives the process pump or generator, and the exhaust gas is used as the combustion air of the industrial furnace in the process device or the supplementary combustion or full combustion steam generator to generate steam and then merged into the system.
3.2 Steam system scale||tt ||3.2.1 Classification by capacity:
Small system: maximum steam load 60t/h and below; 3.2.1.2 Medium system: maximum steam load 61~~200t/h; 3.2.1.3 Large system: maximum steam load 201t/h and above. 3.2.2 Classification by the nominal pressure level of the first-level mother pipe of the system: Low-pressure system: steam pressure is generally 1.57MPa and below, 3.2.2.1
3.2.2.2 Medium-pressure system: steam pressure is generally 1.58~～3.82MPa, 3.2.2.3 Secondary high-pressure system: steam pressure is generally 3.83~6.73MPa; 3. 2. 2. 4
High-pressure system: Steam pressure is generally between 6.74 and 13.7 MPa. 3
System composition
In factories and enterprises, various devices and equipment that are responsible for steam production and transportation, recovery of condensate, waste heat, and exhaust gas, and providing thermal power, and are connected in the form of steam or thermal energy, and a unified, coordinated, and balanced system composed of various instruments, is called a steam system. The main components are: boiler room or thermal power station; auxiliary boiler or start-up boiler; waste heat and exhaust gas recovery device; steam transportation, distribution and balancing facilities; steam and heat users, industrial and power generation steam turbines: feed water deoxygenation and condensate recovery system: gas turbines, expanders and their energy recovery devices. The detailed composition is as follows.
4.0.1 Steam consumers take steam from the system, which cannot be returned to the system users in the form of steam after use. Generally there are the following categories: Steam for chemical reaction processes:
4. 0. 1. 2
4. 0. 1.4
4. 0. 1. 5
4. 0. 1. 6
4. 0. 1. 10
Steam for vacuum injection or material atomization:
Steam for isolating air;
Mixing heater;
Condensing surface heater:
Condensed steam from condensing steam turbine and extraction condensing steam turbine: Steam for heating and domestic use:
Steam supplied to the outside of the system;
Insulation, heating and purging of materials;
Pipeline network losses.
Steam user
Steam taken from the system; after use, only the parameters are changed, and the steam can still be returned to the system for reuse in the form of steam. Generally, there are the following categories: 4. 0. 2. 1
Back pressure or extraction back pressure steam turbine;
The extraction part of the extraction condensing steam turbine: 4.0. 2. 2.
Steam accumulator
4.0.3 Steam source refers to the equipment or device that generates steam (including external steam), such as: steam boiler (including self-provided thermal power station boiler, start-up boiler, auxiliary boiler); 4.0.3.1
4.0.3.2 Waste heat boiler;
Flash expansion tank;
4. 0. 3. 3
4. 0. 3. 4
External steam.
Feedwater system:
4. 0. 4. 1
4. 0. 4.2
4. 0. 4. 3
Heating of low-temperature return water and boiler feedwater;
Deoxygenation of feedwater;
Dosing of feedwater and boiler water.
Condensate and wastewater recovery system and steam-water quality monitoring facilities: 4.0.5
4. 0. 5. 1
Condensate recovery, flash evaporation and cooling,
Flash evaporation, recovery of boiler wastewater and cooling and discharge of wastewater; 4. 0.5.24
4.0.5.3 Steam-water quality monitoring and sampling;
4.0.5.4 Drainage.
4.0.6 System balancing facilities:
4. 0. 6. 1
Steam distribution:
4.0.6.2 Pressure reduction is generally used only for steam load regulation. If it is used as a steam bypass backup for steam turbine extraction and exhaust, it should have automatic start-up and quick start functions; 4.0.6.3 Temperature reduction is generally matched with pressure reduction facilities. When the superheat of steam turbine extraction and exhaust is high and does not meet the process heating requirements, water spray temperature reduction facilities are installed on the steam pipe upstream of the steam-using equipment or on the system with independent parameters; 4.0.6.4 Safety mainly refers to the overpressure discharge facility 4.0.6.5 Exhaust condensation is often opened, stopped and temporarily discharged with a large amount of steam, and there is a dispatchable circulating cooling water volume, so this facility should be installed: 4.0.6.6 Recirculation refers to the recirculation pipe and the flow limiting orifice plate installed: 4.0.6.7 Venting - generally refers to the venting regulating valve installed on the steam main pipe of each pressure level to control the main pipe pressure.
4.0.7 Gas turbine, expansion turbine and its exhaust utilization system: 4.0.7.1 Gas turbine exhaust enters the process heating furnace; 4.0.7.2 Gas turbine exhaust enters the steam boiler; 4.0.7.3 Utilization of waste heat from expansion turbine exhaust. 6
5 System formulation
5.1 Basis for formulation
5.1.1 Approved project documents.
5.1.2 Implemented external conditions.
5.1.2.1 Information on fuel, transportation, water source, electricity, geology, meteorology, chemicals and environmental protection requirements.
51.2.2 System load conditions
(1) Process steam load and parameters (according to Appendix B Table B1) (2) Steam engine pump characteristic data (according to Appendix B Table B2): (3) By-product steam data (according to Appendix B Table B3); (4) Consumption, annual utilization factor of steam-using equipment (5) Original steam source conditions;
(6) Process waste heat data (according to Appendix B Table B4): (7) Condensate recovery data (according to Appendix B Table B5) (8) Protocol on steam load and condensate recovery for external cooperation.
Characteristic data and charts of major thermal equipment in the system. 5.1.3
General principles for system planning
5.2.1 The system should be equipped with boilers with the same parameters and capacity, and the parameters of waste heat boilers should match the system parameters.
5.2.2Except for waste heat boilers and start-up boilers, the steam boilers installed in the system should produce steam with the highest pressure level in the system.
5.2.3When supplying steam to a process unit that operates continuously for more than 6,000 hours per year, a single coal-fired boiler should not be used as the steam source. A maintenance boiler or room for expansion can be determined through technical and economic comparison.
5.2.4Decompression and temperature reduction devices should be considered between steam main pipes of various pressure levels in the enterprise. The steam temperature at the outlet of the desuperheater should be not less than 25°C. The temperature measuring point for adjustment should be set on the 8m~12m pipe section after the water spraying point. The water pressure for desuperheating spraying should be 1.5MPa higher than the outlet steam pressure. The water quality of the spraying water should meet the requirements of the steam quality after desuperheating.
5.2.5The condensate of steam consumers should be fully recovered and reused multiple times according to the pressure level to improve the thermal utilization rate of the system and reduce the amount of make-up water. 5.2.6 To ensure the deaerator effect, the deaerator inlet water temperature should not be lower than 60℃ for atmospheric deaerators, and the upper limit should be at least 15℃ lower than the saturation temperature at the operating pressure of the deaerator for spray deaerators.
5.2.7 To facilitate the use of process waste heat and system low-pressure steam, the first-stage deaerator should adopt an atmospheric deaerator.
5.2.8 To improve the thermal efficiency of the steam system, medium and low temperature waste heat should be used to heat the deaerator feed water or boiler feed water.
5.2.9 The steam supply, feed water and condensate return pipelines should adopt a single mother pipe system. 5.2.10 The steam main pipes of each pressure level in the system should be equipped with safety discharge devices. The steam can be discharged to the residual steam condenser or to the atmosphere through the muffler. 5.3 Principles for the pure heating system
5.3.1 Understand the special requirements for heating during the start-up and shutdown of the chemical process and production. It is advisable to obtain the load curve for the main steam consumers and study their reliability in detail. 5.3.2 According to the process steam load and parameter characteristics, combined with the steam parameters of the steam source equipment 8
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