化工过程机械专业研究生专业英语讲座课件讲义.ppt

1、1Process TechnologyChapter 13Utility SystemsZhengdong Wang(王正东)Room 333,Bldg.17,Tel.:2Utility Systems around YouuPower supply system(electricity)uTap water system(running water)uGas supply systemuTelephone lineuInternet connection system(ISP,ADSL)uCable TV systemuGlobal positioning system(GPS)uUtili

2、ties billing system3Objectives to describeBasic components of a steam systema raw water systema fire water system a cooling water systeman air systema nitrogen systema gas systeman electrical systeman industrial sewer systema process refrigeration systema relief and flare system4Utility Boiler(Wujin

3、g)5Coal fired boiler(Waigaoqiao)6Provance Power Plant7Introduction to Process Systems Chemical plants and refineries include unique combinations of equipment and systems that are used to separate materials into pure or relatively pure products.Examples of process systems include reactions,distillati

4、on,absorbing/stripping,adsorption/drying,crystallization,evaporation,extrusion,extraction,filtering,screening,and utility systems.Plant utility systems typically include,steam generation,compressed air and gases,water treatment,and cooling tower operations.8Steam Generation SystemsuBoiler(fire tube

5、or water tube)uSteam header system(low,medium and high pressure)uCondensate return system(steam traps,valves,piping,pumps)uDeaerator systemSteam systems can include super high pressure(SHP)steam generation and distribution,high pressure(HP)steam,medium pressure(MP)steam and low pressure(LP)steam 9St

6、eam Generation SystemsuSuper High Pressure(1000-1200 psig)uHigh Pressure Steam System(400-800 psig)uMedium Pressure Steam System(180 to 200 psig)uLow Pressure Steam(50-60 psig)*1 psi=6895 Pa=0.006895 MPa =0.06895 bar；1bar=14.50 psi10Condensate Recovery System The condensate recovery system is separa

7、ted into clean and suspect(dirty)condensate sections.Clean condensate is routed to the deaerator.Suspect condensate is collected from steam users where the process side pressure is higher than the steam pressure.11Raw Water and Fire Water System The normal plant supply for the raw water(RW;used for

8、all purposes throughout the plant)and fire water(FW;used only in specific units such as boilers,and usually must be treated for purity)systems comes from a storage reservoir that is supplied from municipal sources or local rivers and lakes.Raw water is supplied to the units in the plant by pumps.All

9、 pumps can be remotely started from a utilitys unit control service.12Water Systems13Boiler Feed Water Treatment Boiler feed water treatment is the process by which suspended and dissolved solids are removed from the waste used in a plant.Clean condensate and demineralized makeup water are deaerated

10、 in order to supply boiler feed water(BFW)to multiple BFW pumps.Two or three pumps are used in the pump-around operation.The primary pump typically has one or two backup pumps that are placed in standby mode.14Boiler Feed Water15Cooling Water System The cooling water(CW)system is used for cooling th

11、e various pieces of equipment in the facility in a closed cooling system.The cooling water system is divided into two complementary circuits.One circuit operates on a once-through basis;the other allows the reuse of water to cool a second train,after use for cooling the first train.16Air Systems Uti

12、lity and instrument air are both supplied from centrally located air compressors.Drivers for the compressors are arranged so that the loss of power or steam will not interrupt the supply of critical instrument air.Some plants have additional diesel driven compressors in case the two utilities are no

13、t available at the same time.17Nitrogen Systems Nitrogen gas is usually generated in the plant or purchased from a supply company.If purchased,it is usually delivered by high-pressure pipeline.Pipeline pressures run from 300 to 600 psig.The supplier may own and operate the meter station,which forms

14、the billing basis for the purchase of nitrogen.18Natural Gas System Most industrial manufacturers purchase natural gas(NG)from suppliers.A high-pressure pipeline generally delivers gas to the plant.A pressure letdown station located near one of the plant entrances meters flow to the plant.The letdow

15、n station consists of multiple control valves,two of which are normally in service for backup.Additional valves are provided for peak loads such as unit startups.The letdown/meter control valve is in operation at all times.A second valve opens when the flow rate is high and clones at low flow rates,

16、thereby making possible more accurate metering of the gas flow.19Electrical Systems The power received from electric supply companies is generally at voltage levels of 100 to 160 kV.At many plants,this is transformed down To 13.8 kV for distribution within the plant.At the units,the 13.8 kV is stepp

17、ed down to 4160 V for-use on large motors(200-10,000 hp).The 13.8 kV is also transformed to 480 V,the most common voltage in many plants,and finally to 240 V and 120 V for heating,lighting,and fractional horsepower motors.20Steam Systems Steam has been used as a source of heat and a conveyor of ener

18、gy since the Industrial Revolution.It is produced by boiling water and its temperature or heat value can be easily determined because it generally corresponds to the pressure in the system.Steam carries large amounts of energy in small mass flow rates;the energy of steam is readily transformed into

19、mechanical or heat energy upon condensation.21Steam Distribution System22Industrial Sewer System A plant sewer system collects all drains(water and process fluids)from the process units.All water is collected in a series of ditches and routed to the plant waste treatment area.Units that have hydroca

20、rbons that will remain in the liquid phase at ambient temperatures have an API separator,which separates the oil phase from the water phase before routing the water to the plant sewer system.Removed oil is rerun or used for fuel.Some plastic units have only a simple system to remove oil and pellets

21、before sending the sewer water to the plant system.23Refrigeration System Heating and cooling are two important aspects in modern process control.Refrigeration systems,such as air conditioning are used to provide cooling to industrial applications.Refrigeration units are composed of a compressor(hig

22、h-pressure refrigeration gas),a heat exchanger(cooling tower),a receiver,an expansion valve(low-pressure refrigeration liquid),and another heat exchanger(evaporatorlow-pressure refrigerant gas).24Simple Refrigeration System25Refrigeration Cycle26Relief and Flare SystemuFlare systems are used to safe

23、ly remove excess hydrocarbons from a variety of plant processes.Flare systems are composed of a complex network of pipes and headers connecting to a knockout drum and flare.Governmental laws and regulations require the flare to be located a safe distance from the operating units and populated areas.

24、27Flare System28Storage Systems Tanks of various types are used for the storage of raw materials and finished products.Since they represent a large concentration of value,the protection and safe operation of storage tanks is important.It is necessary that the operators utilizing storage tanks be com

25、pletely familiar with the tankage and related equipment.29Various Types of TanksuAtmospheric Tanks Cone roof tanks Floating roof tanks Other types of atmospheric tanksuPressure Tanks Drums Spheres Spheroids30Summary Utility systems are the combinations of equipment that are used to provide a plant w

26、ith water,fuel,air,nitrogen,electricity,refrigeration,and other substances or processes it needs to operate.In general,utility systems either separate materials into pure or relatively pure products or distribute supplies to the plants units in useable amounts,store supplies,and remove waste products.31End