I-DRMS System of calculation of material balances

The I-DRMS system is intended for automation of calculation of the approved material balances, identification of gross errors in measurements and determinations of places of emergence of losses. The developed modeling tools, calculation and reporting do the I-DRMS system by an irreplaceable part of the general system of production accounting of the enterprise.

I-DRMS performs the following functions:

• creation and maintaining mathematical model of material flows;
• error trapping in measurements;
• calculation of material balances;
• calculation of the actual losses;
• planning of upgrade of a measuring system;
• providing third-party applications with consistent balance.

Main objective of implementation of an automated system of calculation of material balances is automation and a regulation of business process of production accounting that allows to create the uniform approved material balance unambiguously connected with primary measurements.

Production accounting is the major management process affecting all aspects of tactics and the strategy of the enterprise. A key subject in this process, certainly, is the material balance of production. However settlement process of the approved consistent material balance is strongly complicated for a number of reasons. A set of primary measurements obviously contains errors, a part of the material balances given for calculation are entered manually, all this interferes with an opportunity to carry out the economic and technology analysis of results of work of the enterprise. The automated system of calculation of material balances of I-DRMS successfully eliminates errors of measurements and creates the uniform approved material balance.

Modeling of material flows

For creation of a mathematical model real technology schemes of the enterprise come down to simplified diagrams of material flows. Depth of modeling of productions, workshops and installations by selection of balance sheet objects (nodes, reservoirs and installations) which in model are considered as "a black box" is defined – only inputs and exits of objects are displayed, and their internal communications are not considered. Flows only between objects and changes of reserves of substances in them are considered.

Material flows and stocks depending on the purpose of creation of model can be defined by the physical mass of substance of a flow (stock) or the target substance (product) selected from it on which the balance comes down.

All original informatin for calculation of the approved material balance is generated by the unified information system of production providing collecting and standardization of data from all sources of information at the enterprise (on sensors, tanks, analyzers, transactions, acceptance, shipment, etc.).

Detection of gross errors of initial data

The existing techniques of approval of data and, in particular, data of balance rely on the assumption that errors in data have the accidental nature. Existence in the system of nonrandom gross errors can lead at data of balance to overestimated and even to unacceptable corrections of the measured data therefore the condition of application of a method of data of balance is the absence in the system of gross errors. The following types of gross errors are generally selected:

• errors of measurements of flows and determinations of a remaining balance;
• not identified losses in balancing nodes (outflow/inflow of weight);
• unaccounted transactions of a material transfer.

Use of several methods of identification of gross errors, such as is provided in I-DRMS:

• the method based on the general analysis of not balances in a system (GlobalTest – GT);
• the method based on the item-by-item analysis of not balances in a system (Nodal Test – NT);
• the method based on the analysis of correction of measurements at approval of a material balance (MeasurementTest – MT);
• the method based on the analysis of all possible overflows between balance sheet nodes of model.

Also ad hoc methods according to specific specifics of model and quality of initial data can be developed.

After elimination of all possible gross errors the imbalances which remained in a system rank as not identified losses.

Calculation of a material balance

When calculating material balances discrepancies between the measured production data and the known balances of weight are eliminated. Finding of such minimum amendments to measurements that matched data satisfied to the restrictions caused by conservation law of masses is result of calculation. The material balance comes down for respect for equality of entrance and output flows (taking into account change of stocks) on any object (the reservoir, installation, a node) of the enterprise. Accomplishment of such conditions automatically means accomplishment of balance sheet conditions as for any structural divisions of the enterprise (workshops, sections, etc.), and for the enterprise in general. In addition I-DRMS monitors observance of limits of metrological admissions of devices and technological limits on ratios of flows.

Calculation of the actual losses

The actual losses at the enterprise consist of two components: the identified and not identified losses.

• The identified losses – a part of losses by production, storage and/or material handling which value can be estimated (is expected) specific timepoint (for example, losses of products at shipment to tank cars and automobile tanks, losses by preparation for carrying out repairs of installations and the equipment, etc.).
• Not identified losses – a part of losses by production, storage and/or material handling which value cannot be estimated (is calculated) owing to lack of data on their sources or lack of techniques of their calculation (a nonexcluded component of systematic inaccuracy of measurements, distortions in accounting, plunders, etc.).

The identified losses are calculated and join in model of material flows with the corresponding error of their determination.

For calculation of not identified losses errors of measurements of masses for all objects, including tanks and metering stations include in model of material flows. Then, on condition of absence in initial data of gross errors, a system finds the minimum mass imbalances (not identified losses) on each balance sheet node with correction of all initial data, including the identified losses within metrological restrictions.

The actual losses in general on the enterprise are calculated as the amount of values of the identified and not identified losses in all places of their emergence.

Upgrade of a measuring system

For the analysis and quality control of a measuring system in I-DRMS the following functions are used:

• calculation of an integrated error of a measuring system of the enterprise in general and key objects in particular (determination of value of the minimum possible detected not balance, leaks);
• calculation of assessment of "observability" of not measured material flows;
• calculation of assessment of "redundancy" of the measured material flows, redundancy of a measuring system in general;
• calculation of absolute errors of the measurements corrected at data of a material balance and errors of observed flows;
• calculation of matrixes of influence of errors of each of the measuring instruments (MI) on errors of determination of other flows in a system and also on thresholds of possible leaks;
• providing to the user an opportunity to make the analysis of SI in an interactive mode and to plan its upgrade.

This functionality helps to upgrade a measuring system effectively: optimize arrangement of measuring devices and formulate requirements to their classes of accuracy.

Automated system of calculation of material balances in structure of production accounting of the enterprise

Before implementation of the automated system of calculation of material balances (ASCMB) the enterprise needs to create a subsystem of primary production accounting at the level of supervisory control. The subsystem of primary production accounting should provide:

• the automated collecting of all measurements with the PCS, ASTUE, LIMS;
• manual entry of data from non-automated objects;
• management of NSI (metrological characteristics of measurements, mass of systems);
• accounting of the movement of raw materials of semi-finished products of products on the enterprise;
• calculation of mass of flows and remaining balance in case of lack of direct measurement of masses;
• formation of the operational reporting under technology objects, productions and enterprise.
• The created set of primary measurements automatically is transferred to ASRMB that provides an opportunity to connect all primary measurements with the aggregated and approved values in ASRMB.

The system of calculation of material balances is a part of an end-to-end system of operational production management and provides other its subsystems with reliable operational data on material balances of objects of the enterprise for such tasks as calculation of specific costs of energy resources for the processed raw materials ton, the analysis the plan/fact, etc.

Existence of the approved material balance for the daily periods gives the chance to increase efficiency of use of the systems of the class ERP. For example, to calculate product cost, to make objective plans for processing of products, considering the actual opportunities of production.

Structure of a system

Are composition: I-DRMS-SM server
Main modules of the server:

• Module of storage of an object model and design data.
• The module of data sources (Data Reference) intended for loading and processing of input data. This module allows to load data from different sources, including, from relational databases, for example, from SQL Server, from BDRV (PI System of company OSIsoft, Proficy Historian of GE IP company), and also to make independent calculations.
• The module of expansions allowing to connect a set of the modules solving versatile problems including integration with external ASUP.
• The module of expansions allowing to create a set of reports.
• The module for work with OSIsoft Asset Framework Server which is used if data source is PI System (OSIsoft).