- Email: [email protected]
A large-scale energy reporting system for the process industry
e>
Computers and Chemical Engineering Supplement (\ 999) S597-S6OO © 1999 Elsevier Science Ltd. All rights reserved PH: S0098·1354199Ioo135·0
Pergamon
A large-scale Energy Reporting System for the Process Industry B. Glemmestad', K.W. Mathisen", K.L. Grenn", T. Haug-Warberg", l.A. Gravklev' I.2'SNorsk Hydro, Research Centre, Porsgrunn, Norway 3 Norsk Hydro, Hydro Data, Porsgrunn, Norway 4 Telemark College, Dept. of Technology, Porsgrunn, Norway Abstract - Energy management represents an important issue within the process industry. The lack of a unified, simple and consistent standard for energy loss calculations constitutes an obstacle in further progress towards more energy efficient plants and sites. A unified approach in order to assess energy efficiency and identify losses in plants or at complete sites is needed. This paper describes the results of ongoing work in order to improve energy efficiency within Norsk Hydro. This involves a consistent method for energy loss calculations and a reporting system. An important feature of the method for energy loss calculations is that measurement of recipient streams such as cooling water and effluent gas is not needed. The reporting system is based on WeblIntranetllava technology and an Oracle database. At present, the energy reporting system is implemented and it is running on some test plants. Work for large-scale implementation including Norsk Hydro's 200-300 plants worldwide is currently taking place. Keywords: Energy, industrial application. reporting system, energy loss.
INTRODUCTION The process industry is a large consumer of energy. Basically, industrial activity involves conversion of raw material into products of higher value. At the same time energy is transformed. In many cases, energy is converted from high grade (e.g. hydrocarbons and electricity) to low grade (e.g. cooling water, effluent gas and steam) in addition to the energy content in the main products. The goal of the work presented in this paper is to improve the energy efficiency within Norsk Hydro. A prerequisite for improving energy efficiency is to have a thorough knowledge and understanding of the current situation. That is, in order to make the right decisions related to utilization of energy, one has to know which . processes that are large consumers of energy and which processes that already utilizes energy efficiently. In a large international corporation operating on different industrial branches and comprising a large variety of different processes, the task of having a clear understanding of energy efficiencies for all different process types represents a challenge. Today's situation is characterized by several different methods for different industrial branches. Each method may be well suited within the industry it is aimed for, but the different methods do not correspond to each other. As a consequence, a figure for specific energy consumption given in e.g. Gllt may have different meanings depending on whether it is for an ethylene plant computed according to CEFIC (European Chemical Industry Council), whether it is for an ammonia plant computed according to directions given by EFMA (European Fertilizer Manufacturing Association) or
whether 'it is for an aluminum electrolysis plant computed from consumption of DC electricity only. A unified and consistent method for calculations related to energy efficiency is needed. Such a method has been developed over the past years within Norsk Hydro (Haug-Warberg, 1998) (Mathisen et al., 1999) and it forms an important basis for the energy reporting system. The method utilizes a novel thermodynamic reference state (Haug-Warberg, 1998). The method for energy loss calculation is combined with an efficient reporting system. This is necessary in order to obtain a good knowledge of the energy efficiency for many different processes within a large corporation. The reporting system is a computer application based on WeblIntranetl1ava technology combined with an Oracle database . This paper describes ongoing activities within Norsk Hydro in order to achieve a large-scale and corporatewide reporting system based on a consistent method for energy loss calculations. The remaining part of the paper is organized as follows: The subsequent section describes briefly the new method for calculation of absolute, relative and specific energy loss. Then, the reporting system (software application) is described. Results for a typical industrial process are shown. Finally, conclusions and some directions for further work are given. ENERGY LOSS CALCULATIONS This section provides a short description of the method for calculation of energy loss that is implemented in the energy reporting system. The method is presented more thoroughly in Mathisen et al. (1999).
Computers and Chemical Engineering Supplement (/999) S597-S600
5598
Existing industrial standards for computing energy efficiency often distinguish between energy on one side (energy streams) and raw materials and products on the other side (material streams). For example, energy input may only include electricity, steam and possibly energy content of hydrocarbons while energy in other input streams is disregarded. It is not unusual to totally disregard energy in the outflows. This represents one obstacle related to consistent energy loss calculations since it may not always be clear which streams that are regarded as energy streams. Further, streams that are considered as material streams (e.g. products) may have a significant energy content that is disregarded. In the method described here, this distinction between energy streams and material streams is not adopted. The method is based on a block decomposition of industrial sites and plants. Each block is called a process and, when possible, the boundaries for processes are selected so that they match existing technological and/or economical boundaries. At these boundaries, good and reliable data for material flows and electricity usually exist and the energy flows may be calculated with good accuracy. The total energy inflow is denoted "energy supply" and this includes all raw materials, fuels, steam, electricity etc. The total energy outflow is divided into "energy delivery" and "energy loss", see Figure 1. Energy delivery includes all energy that goes to further refinement or end-users. Energy deliveries include main products, byproducts, steam. electricity, hot water, fuel gas etc. Energy loss is defined as energy that is lost from the industrial value chain and enters the environment. The total energy loss is calculated as the difference between energy supply and energy delivery. Typically, energy loss contains heat transferred to cooling water, energy in effluent gas, diffusive heat loss to the surroundings or waste chemicals delivered to special land fill etc. Energy supply ES"(ply
Energy delivery Process
ED
• Energy loss, EL= Figure 1. Sketch of general process with inflow and outflows of energy.
except for streams that include nitrates. For processes that include nitrates. a nitrate (e.g. KNOJ ) may be selected as reference for the nitrogen element Instead of N2 in order to achieve positive enthalpy values. One benefit from selecting a set of low-energy, recipient chemicals as reference for energy is that uncertainties in flows such as process water, process air and other recipient chemicals do not affect the energy balance calculations significantly (since they have zero or very low energy content). This is important as such flows are most often not accurately known. Further, the industry has good systems (accurate measurements etc.) for substances and energy that are purchased and sold such as raw materials, electricity and products. That is, energy supply and energy delivery are accurately known. The energy loss including effluent gas, heat to cooling water etc. is usually not very accurately known. From an energy balance, however, the total energy loss per time period can be computed as
where if is enthalpy per time period (OJ/time unit) for the flows. if is computed as iii • h, where iii is mass flow and h is specific enthalpy according to the new thermodynamic reference state. Qis useful thermal heat not associated with convective process flows. W is work, in practice electricity or shaft work in compressor/turbine trains. Notice that recipient chemicals may be omitted in the list of inflows as their specific enthalpy values are zero. Furthermore note that all loss flows are omitted for the list of delivery flows. In many cases, the absolute energy loss, El.o ss , will be a useful energy related Key Performance Indicator (KPI). Two other KPIs that often give valuable information about the energy efficiency of a process are Relative Energy Loss (REL) and Specific Energy Loss (SPEL). The relative energy loss is defined as
REL =
. ~l.oS~
(H + Q + W)Supply
When all enthalpy flows are non-negative we have 0::;, REL s 1. When key product(s) are identified the specific energy loss can be computed as
SPEL = ~l.oSS
mprod
Another obstacle related to consistent energy calculations for different types of plants is the different reference points used for energy. The method described here is based on a novel thermodynamic reference state where the most stable and abundant form of each element on the earth is used to define the zero tangent plane for energy. Examples of substances with zero energy at a reference temperature are water, air (N2, O2 and Argon), CO2 and a set of common minerals such as calcite (CaCO J ) , dolomite (MgCOJ'CaCOJ ) , quartz (Si0 2) and others. The selected zero tangent plane guarantees positive enthalpy values for all streams with temperature larger than the reference temperature,
where IiIprod is the amount of key products. Notice the difference between this definition of specific loss and other definitions with only "energy input streams" such as electricity, steam and fuel in the numerator. These three KPIs give a consistent picture of the energy loss regardless of process type. The three KPIs give different information about the process and which one(s) to use depend on the application.
THE REPORTING SYSTEM The reporting system is denoted HERE. This is an acronym standing for Hydro Energy, Resource &
Computers and Chemical Engineering Supplement (/999) S597-56OO
Environment. The resource and environment parts exist in the reporting system, but these are not considered in this paper. For the method described in the previous section, a process is defined through its supply and delivery flows. All such flows must be identified and specified in terms of chemical composition, temperature, pressure and aggregate state. When a process is defined it may be registered in the HERE information system. When the process is registered in HERE, data for the mass flows (or electricity) of the supply and delivery flows may be registered and energy related KPls may be accessed. Some important requirements for a reporting system in a large corporation are:
•
Accessibility for everyone within the corporation throughout the world.
•
User-friendliness, only basic computer experience should be necessary.
•
Confidentiality, the system should be able to handle confidential information as detailed information about material and energy flows may be classified.
"
Maintenance, it have to be simple to install new versions of the software.
Further, it must be possible to control read and write access. It is also necessary with a flexible system that can be extended to other than just energy related information (e.g. environmental or resource data). Based on these requirements.: the choice was to develop an information system based on a server with an Oracle database, and PC clients communicating through Hydro Interlan (Intranet) using a standard Web browser to access the database. The software architecture of the HERE information system is shown in Figure 2.
Figure 2. Software architecture of the HERE information system. One important feature with the software architecture is that no software installation (in addition to the default
S599
software installed on a standard PC within Hydro) is required on the PC clients. Thus upgrades are made on the server only. The database mainly contains three different types of information: I. The process definitions including which supply and delivery flows each process consists of. 2. A flow list containing specific enthalpy values for all streams (one single list for all processes). 3. Actual registrations of supply and delivery flows quantity given in tonnes for material flows (or GJ for electricity) for the processes. These registrations also contain the time for each registration. Hydro Interlan communicates with the information in the Oracle database through a standard Web server (Netscape). The Web server uses the CGI (Common Gateway Interface) program to send SQL (Structured Query Language) commands to the Oracle database via the ODBC (Open DataBase Connectivity) interface. The user access the reporting system through a PC using a Web browser (Netscape) that communicates with the NT Server. The client PC may initiate Java applets through H1ML (Hyper-Text Markup Language) code. The NT server only stores the registered processes, the flow list and the flow registrations. All computations of energy related KPls etc are done at the client PC by means of Java applets. That is, when for instance a report for a process is requested by a client PC, the relevant data is first transferred from the database at the server, then the required computations are done at the client PC and the report is presented on the screen (or printed, or exported to a standard spreadsheet text format if further processing is desired). Read and write access to the different operations and for different processes are controlled through user name and password. In order to handle classified information, data transmitted on Hydro Interlan is encrypted. An example of a screen shown on a PC client is shown in Figure 3. Only the most important part of the screen is shown here. When a process is defined it can be registered in the HERE system by selecting "New Process" from the menu to the left in the figure. If all flows for the new process is already defined, the new process can be defined immediately. If the new process contains flows that are not previously defined, the new flow(s) must be entered in the flow list before the new process can be defined. For a process that has been defined in the HERE system, actual data for the supply and delivery flows.can be registered. Figure 3 shows the screen for such a registration when the choice "New Registration" has been selected from the menu. A PVC-plant has been selected since this can be realistically represented with only a few flows (supply flows: vinyl chloride, electricity and steam, and only one delivery flow which is PVC). The data shown in Figure 3 are not for a real PVC-plant, but gives a realistic picture. The data to be registered are entered in the white fields. For example,
Computers and Chemical Engineering Supplement (1999) 5597-5600
5600
.
HERE Register EnerlO' Datil
Regls!er energydata for a specjj!c ProcessJ?eriod HERE
I~ .,.
I L.·,~ :·c-·l
Division:
0'I11ge V1r!
''''Odify Ae'iltrn:o',
Unit
0'I11ge V1r!
F";;dWy;;o...
I
IH_ P erma "." ;_1
P ....IfyP._, I g"Uil
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I~~
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To Date: 1999-01·31
From Da!e: 1999-01·01
' roc.. :
~
I
Help
Calculated Specr.lc EnergyConsumpUon:
PVC..xample
r N" R.g~.tiO~ I I,: H.
Norsk Hydro
6.14
OJIlon
2.05 WIMan 2H9
%
IFlowtode ISupplyh4ass Intons & E.j De l~ry h4ass In tons J, Key Product ISupply(OJ) IDe llvery(OJ) IFlow 0.0 IVlClt.Chor1deQ.4~ar,q C2H3CI(I) I 9100.0 I 1' 63943.85 I 01 0.0 IEletlr1city IElectrlcity I 131000 I 01 I 13700.0 IH20(g,200C,14bal) IH20(g,2 00~ 0.0 140000 I 01 I 37778.42 Ves IPoJ.,.r.Clt.chorideCs) IPVCls) I 9000 0 I oI 001 180121.47 I
I
I
o· , WOdrffR.potlt'OU
Sum
I 235422.27 r 180122-:47
I': En_ttYR.pons I'.. E~;o-tlf".nt.lio. . I:
- - -..---.
..
; ·l .... Up
Key Product(s): PoJ.,.r.Clt.chorideCs)
Key ProductCs) Amount
Figure 3. Example of screen at client PC using the HERE information system. the production quantity of PVC in the time period for this registration (January 1999) is 9000 tonnes PVc. The energy content (the two columns to the right) is computed/updated when each new number is entered. KPIs are also displayed on this screen. t Loss is not shown directly in this version of HERE, but is easily found to be 235422-180122 =55300 OJ (sum supplysum delivery). The relative energy loss is displayed (23.49 %) in addition to the specific energy loss (6.14 G1It PVC). When the OK button is pressed the entered data are stored in the database on the server. Later, any user with read access to the relevant processes can access the HERE system and select "Energy Reports". Registrations for a selected time period and KPIs including historic trends can be shown on a client PC through various choices. The HERE information system as described above fulfills the four requirements from the previous page, and it includes the consistent method for energy loss calculations described in the previous section. In addition to these technical aspects the organizational implementation of such an information system represents a challenge. At present, the reporting system is not generally implemented within Norsk Hydro. It is currently being used for registrations of real data and energy loss calculations for more than 30 different processes. Corporate-wide implementation will take place during 1999.
CONCLUSIONS AND FURTHER WORK A energy reporting system suited for large-scale implementation in a corporation is describ ed. The system consists of two main parts: 1. A consistent method for energy loss calculations and the definition of energy related Key Performance Indicators for industrial processes . 2. A reporting system based on Web/Intranet technology suitable for international corporations.
9000.0 ton
-
The method for energy loss calculations is based taking into account energy supplied to a process and all energy delivered to other processes. A novel thermodynamic standard state to define the reference point for energy is used, and the energy less is calculated as the difference between supplied and delivered energy. The method is insensitive to uncertainties in process water and process air as these have negligible energy content when the new reference state is used. The reporting system has been successfully tested at a few test plants in Norsk Hydro. Large-scale implementation throughout the corpor ation worldwide will take place during 1999. In this paper, only the energy part of the HERE information system has been presented. HERE also includes environmental information, and other HES data is expected to be included in future versions. Ongoing theoretical work related to energy availability is also expected to result in additional KPIs that will be implemented in HERE.
all
REFERENCES Haug-Warberg, T., (1998) , Specific Energy Consumption in Flow Processes - Basic Theory and Calculated Examples, 4th ed. Internal report, Dept. of Technology, Telemark College, Porsgrunn, Norway. Mathisen, KW., T. Haug-Warberg, B. Glemmestad and J.A. Gravklev (1999), Consistent Computation of Energy Loss for Industrial Processes, Presented at PRES'99. 2nd Conference on Process Integration, Modeling and Optimization for Energy Saving and Pollution Reduction, May 31 - June 2 1999, Budapest, Hungary.
Computers and Chemical Engineering Supplement (\ 999) S597-S6OO © 1999 Elsevier Science Ltd. All rights reserved PH: S0098·1354199Ioo135·0
Pergamon
A large-scale Energy Reporting System for the Process Industry B. Glemmestad', K.W. Mathisen", K.L. Grenn", T. Haug-Warberg", l.A. Gravklev' I.2'SNorsk Hydro, Research Centre, Porsgrunn, Norway 3 Norsk Hydro, Hydro Data, Porsgrunn, Norway 4 Telemark College, Dept. of Technology, Porsgrunn, Norway Abstract - Energy management represents an important issue within the process industry. The lack of a unified, simple and consistent standard for energy loss calculations constitutes an obstacle in further progress towards more energy efficient plants and sites. A unified approach in order to assess energy efficiency and identify losses in plants or at complete sites is needed. This paper describes the results of ongoing work in order to improve energy efficiency within Norsk Hydro. This involves a consistent method for energy loss calculations and a reporting system. An important feature of the method for energy loss calculations is that measurement of recipient streams such as cooling water and effluent gas is not needed. The reporting system is based on WeblIntranetllava technology and an Oracle database. At present, the energy reporting system is implemented and it is running on some test plants. Work for large-scale implementation including Norsk Hydro's 200-300 plants worldwide is currently taking place. Keywords: Energy, industrial application. reporting system, energy loss.
INTRODUCTION The process industry is a large consumer of energy. Basically, industrial activity involves conversion of raw material into products of higher value. At the same time energy is transformed. In many cases, energy is converted from high grade (e.g. hydrocarbons and electricity) to low grade (e.g. cooling water, effluent gas and steam) in addition to the energy content in the main products. The goal of the work presented in this paper is to improve the energy efficiency within Norsk Hydro. A prerequisite for improving energy efficiency is to have a thorough knowledge and understanding of the current situation. That is, in order to make the right decisions related to utilization of energy, one has to know which . processes that are large consumers of energy and which processes that already utilizes energy efficiently. In a large international corporation operating on different industrial branches and comprising a large variety of different processes, the task of having a clear understanding of energy efficiencies for all different process types represents a challenge. Today's situation is characterized by several different methods for different industrial branches. Each method may be well suited within the industry it is aimed for, but the different methods do not correspond to each other. As a consequence, a figure for specific energy consumption given in e.g. Gllt may have different meanings depending on whether it is for an ethylene plant computed according to CEFIC (European Chemical Industry Council), whether it is for an ammonia plant computed according to directions given by EFMA (European Fertilizer Manufacturing Association) or
whether 'it is for an aluminum electrolysis plant computed from consumption of DC electricity only. A unified and consistent method for calculations related to energy efficiency is needed. Such a method has been developed over the past years within Norsk Hydro (Haug-Warberg, 1998) (Mathisen et al., 1999) and it forms an important basis for the energy reporting system. The method utilizes a novel thermodynamic reference state (Haug-Warberg, 1998). The method for energy loss calculation is combined with an efficient reporting system. This is necessary in order to obtain a good knowledge of the energy efficiency for many different processes within a large corporation. The reporting system is a computer application based on WeblIntranetl1ava technology combined with an Oracle database . This paper describes ongoing activities within Norsk Hydro in order to achieve a large-scale and corporatewide reporting system based on a consistent method for energy loss calculations. The remaining part of the paper is organized as follows: The subsequent section describes briefly the new method for calculation of absolute, relative and specific energy loss. Then, the reporting system (software application) is described. Results for a typical industrial process are shown. Finally, conclusions and some directions for further work are given. ENERGY LOSS CALCULATIONS This section provides a short description of the method for calculation of energy loss that is implemented in the energy reporting system. The method is presented more thoroughly in Mathisen et al. (1999).
Computers and Chemical Engineering Supplement (/999) S597-S600
5598
Existing industrial standards for computing energy efficiency often distinguish between energy on one side (energy streams) and raw materials and products on the other side (material streams). For example, energy input may only include electricity, steam and possibly energy content of hydrocarbons while energy in other input streams is disregarded. It is not unusual to totally disregard energy in the outflows. This represents one obstacle related to consistent energy loss calculations since it may not always be clear which streams that are regarded as energy streams. Further, streams that are considered as material streams (e.g. products) may have a significant energy content that is disregarded. In the method described here, this distinction between energy streams and material streams is not adopted. The method is based on a block decomposition of industrial sites and plants. Each block is called a process and, when possible, the boundaries for processes are selected so that they match existing technological and/or economical boundaries. At these boundaries, good and reliable data for material flows and electricity usually exist and the energy flows may be calculated with good accuracy. The total energy inflow is denoted "energy supply" and this includes all raw materials, fuels, steam, electricity etc. The total energy outflow is divided into "energy delivery" and "energy loss", see Figure 1. Energy delivery includes all energy that goes to further refinement or end-users. Energy deliveries include main products, byproducts, steam. electricity, hot water, fuel gas etc. Energy loss is defined as energy that is lost from the industrial value chain and enters the environment. The total energy loss is calculated as the difference between energy supply and energy delivery. Typically, energy loss contains heat transferred to cooling water, energy in effluent gas, diffusive heat loss to the surroundings or waste chemicals delivered to special land fill etc. Energy supply ES"(ply
Energy delivery Process
ED
• Energy loss, EL= Figure 1. Sketch of general process with inflow and outflows of energy.
except for streams that include nitrates. For processes that include nitrates. a nitrate (e.g. KNOJ ) may be selected as reference for the nitrogen element Instead of N2 in order to achieve positive enthalpy values. One benefit from selecting a set of low-energy, recipient chemicals as reference for energy is that uncertainties in flows such as process water, process air and other recipient chemicals do not affect the energy balance calculations significantly (since they have zero or very low energy content). This is important as such flows are most often not accurately known. Further, the industry has good systems (accurate measurements etc.) for substances and energy that are purchased and sold such as raw materials, electricity and products. That is, energy supply and energy delivery are accurately known. The energy loss including effluent gas, heat to cooling water etc. is usually not very accurately known. From an energy balance, however, the total energy loss per time period can be computed as
where if is enthalpy per time period (OJ/time unit) for the flows. if is computed as iii • h, where iii is mass flow and h is specific enthalpy according to the new thermodynamic reference state. Qis useful thermal heat not associated with convective process flows. W is work, in practice electricity or shaft work in compressor/turbine trains. Notice that recipient chemicals may be omitted in the list of inflows as their specific enthalpy values are zero. Furthermore note that all loss flows are omitted for the list of delivery flows. In many cases, the absolute energy loss, El.o ss , will be a useful energy related Key Performance Indicator (KPI). Two other KPIs that often give valuable information about the energy efficiency of a process are Relative Energy Loss (REL) and Specific Energy Loss (SPEL). The relative energy loss is defined as
REL =
. ~l.oS~
(H + Q + W)Supply
When all enthalpy flows are non-negative we have 0::;, REL s 1. When key product(s) are identified the specific energy loss can be computed as
SPEL = ~l.oSS
mprod
Another obstacle related to consistent energy calculations for different types of plants is the different reference points used for energy. The method described here is based on a novel thermodynamic reference state where the most stable and abundant form of each element on the earth is used to define the zero tangent plane for energy. Examples of substances with zero energy at a reference temperature are water, air (N2, O2 and Argon), CO2 and a set of common minerals such as calcite (CaCO J ) , dolomite (MgCOJ'CaCOJ ) , quartz (Si0 2) and others. The selected zero tangent plane guarantees positive enthalpy values for all streams with temperature larger than the reference temperature,
where IiIprod is the amount of key products. Notice the difference between this definition of specific loss and other definitions with only "energy input streams" such as electricity, steam and fuel in the numerator. These three KPIs give a consistent picture of the energy loss regardless of process type. The three KPIs give different information about the process and which one(s) to use depend on the application.
THE REPORTING SYSTEM The reporting system is denoted HERE. This is an acronym standing for Hydro Energy, Resource &
Computers and Chemical Engineering Supplement (/999) S597-56OO
Environment. The resource and environment parts exist in the reporting system, but these are not considered in this paper. For the method described in the previous section, a process is defined through its supply and delivery flows. All such flows must be identified and specified in terms of chemical composition, temperature, pressure and aggregate state. When a process is defined it may be registered in the HERE information system. When the process is registered in HERE, data for the mass flows (or electricity) of the supply and delivery flows may be registered and energy related KPls may be accessed. Some important requirements for a reporting system in a large corporation are:
•
Accessibility for everyone within the corporation throughout the world.
•
User-friendliness, only basic computer experience should be necessary.
•
Confidentiality, the system should be able to handle confidential information as detailed information about material and energy flows may be classified.
"
Maintenance, it have to be simple to install new versions of the software.
Further, it must be possible to control read and write access. It is also necessary with a flexible system that can be extended to other than just energy related information (e.g. environmental or resource data). Based on these requirements.: the choice was to develop an information system based on a server with an Oracle database, and PC clients communicating through Hydro Interlan (Intranet) using a standard Web browser to access the database. The software architecture of the HERE information system is shown in Figure 2.
Figure 2. Software architecture of the HERE information system. One important feature with the software architecture is that no software installation (in addition to the default
S599
software installed on a standard PC within Hydro) is required on the PC clients. Thus upgrades are made on the server only. The database mainly contains three different types of information: I. The process definitions including which supply and delivery flows each process consists of. 2. A flow list containing specific enthalpy values for all streams (one single list for all processes). 3. Actual registrations of supply and delivery flows quantity given in tonnes for material flows (or GJ for electricity) for the processes. These registrations also contain the time for each registration. Hydro Interlan communicates with the information in the Oracle database through a standard Web server (Netscape). The Web server uses the CGI (Common Gateway Interface) program to send SQL (Structured Query Language) commands to the Oracle database via the ODBC (Open DataBase Connectivity) interface. The user access the reporting system through a PC using a Web browser (Netscape) that communicates with the NT Server. The client PC may initiate Java applets through H1ML (Hyper-Text Markup Language) code. The NT server only stores the registered processes, the flow list and the flow registrations. All computations of energy related KPls etc are done at the client PC by means of Java applets. That is, when for instance a report for a process is requested by a client PC, the relevant data is first transferred from the database at the server, then the required computations are done at the client PC and the report is presented on the screen (or printed, or exported to a standard spreadsheet text format if further processing is desired). Read and write access to the different operations and for different processes are controlled through user name and password. In order to handle classified information, data transmitted on Hydro Interlan is encrypted. An example of a screen shown on a PC client is shown in Figure 3. Only the most important part of the screen is shown here. When a process is defined it can be registered in the HERE system by selecting "New Process" from the menu to the left in the figure. If all flows for the new process is already defined, the new process can be defined immediately. If the new process contains flows that are not previously defined, the new flow(s) must be entered in the flow list before the new process can be defined. For a process that has been defined in the HERE system, actual data for the supply and delivery flows.can be registered. Figure 3 shows the screen for such a registration when the choice "New Registration" has been selected from the menu. A PVC-plant has been selected since this can be realistically represented with only a few flows (supply flows: vinyl chloride, electricity and steam, and only one delivery flow which is PVC). The data shown in Figure 3 are not for a real PVC-plant, but gives a realistic picture. The data to be registered are entered in the white fields. For example,
Computers and Chemical Engineering Supplement (1999) 5597-5600
5600
.
HERE Register EnerlO' Datil
Regls!er energydata for a specjj!c ProcessJ?eriod HERE
I~ .,.
I L.·,~ :·c-·l
Division:
0'I11ge V1r!
''''Odify Ae'iltrn:o',
Unit
0'I11ge V1r!
F";;dWy;;o...
I
IH_ P erma "." ;_1
P ....IfyP._, I g"Uil
1,-H_ R.p.ol't"oup
I~~
Cancel
To Date: 1999-01·31
From Da!e: 1999-01·01
' roc.. :
~
I
Help
Calculated Specr.lc EnergyConsumpUon:
PVC..xample
r N" R.g~.tiO~ I I,: H.
Norsk Hydro
6.14
OJIlon
2.05 WIMan 2H9
%
IFlowtode ISupplyh4ass Intons & E.j De l~ry h4ass In tons J, Key Product ISupply(OJ) IDe llvery(OJ) IFlow 0.0 IVlClt.Chor1deQ.4~ar,q C2H3CI(I) I 9100.0 I 1' 63943.85 I 01 0.0 IEletlr1city IElectrlcity I 131000 I 01 I 13700.0 IH20(g,200C,14bal) IH20(g,2 00~ 0.0 140000 I 01 I 37778.42 Ves IPoJ.,.r.Clt.chorideCs) IPVCls) I 9000 0 I oI 001 180121.47 I
I
I
o· , WOdrffR.potlt'OU
Sum
I 235422.27 r 180122-:47
I': En_ttYR.pons I'.. E~;o-tlf".nt.lio. . I:
- - -..---.
..
; ·l .... Up
Key Product(s): PoJ.,.r.Clt.chorideCs)
Key ProductCs) Amount
Figure 3. Example of screen at client PC using the HERE information system. the production quantity of PVC in the time period for this registration (January 1999) is 9000 tonnes PVc. The energy content (the two columns to the right) is computed/updated when each new number is entered. KPIs are also displayed on this screen. t Loss is not shown directly in this version of HERE, but is easily found to be 235422-180122 =55300 OJ (sum supplysum delivery). The relative energy loss is displayed (23.49 %) in addition to the specific energy loss (6.14 G1It PVC). When the OK button is pressed the entered data are stored in the database on the server. Later, any user with read access to the relevant processes can access the HERE system and select "Energy Reports". Registrations for a selected time period and KPIs including historic trends can be shown on a client PC through various choices. The HERE information system as described above fulfills the four requirements from the previous page, and it includes the consistent method for energy loss calculations described in the previous section. In addition to these technical aspects the organizational implementation of such an information system represents a challenge. At present, the reporting system is not generally implemented within Norsk Hydro. It is currently being used for registrations of real data and energy loss calculations for more than 30 different processes. Corporate-wide implementation will take place during 1999.
CONCLUSIONS AND FURTHER WORK A energy reporting system suited for large-scale implementation in a corporation is describ ed. The system consists of two main parts: 1. A consistent method for energy loss calculations and the definition of energy related Key Performance Indicators for industrial processes . 2. A reporting system based on Web/Intranet technology suitable for international corporations.
9000.0 ton
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The method for energy loss calculations is based taking into account energy supplied to a process and all energy delivered to other processes. A novel thermodynamic standard state to define the reference point for energy is used, and the energy less is calculated as the difference between supplied and delivered energy. The method is insensitive to uncertainties in process water and process air as these have negligible energy content when the new reference state is used. The reporting system has been successfully tested at a few test plants in Norsk Hydro. Large-scale implementation throughout the corpor ation worldwide will take place during 1999. In this paper, only the energy part of the HERE information system has been presented. HERE also includes environmental information, and other HES data is expected to be included in future versions. Ongoing theoretical work related to energy availability is also expected to result in additional KPIs that will be implemented in HERE.
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REFERENCES Haug-Warberg, T., (1998) , Specific Energy Consumption in Flow Processes - Basic Theory and Calculated Examples, 4th ed. Internal report, Dept. of Technology, Telemark College, Porsgrunn, Norway. Mathisen, KW., T. Haug-Warberg, B. Glemmestad and J.A. Gravklev (1999), Consistent Computation of Energy Loss for Industrial Processes, Presented at PRES'99. 2nd Conference on Process Integration, Modeling and Optimization for Energy Saving and Pollution Reduction, May 31 - June 2 1999, Budapest, Hungary.