Ingilizce industrial energy management principles SEÇMELİ

December 8, 2017 | Autor: Asugizem Kcgllgck | Categoría: Engineering
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Ian David Lockhart Bogle and Michael Fairweather (Editors), Proceedings of the 22nd European Symposium on Computer Aided Process Engineering, 17 - 20 June 2012, London. © 2012 Elsevier B.V. All rights reserved.

Case Study – Online Energy Management and Optimisation of Utility Generation Assets on Industrial Sites Solomon Oji Senior Consultant Engineer Aspentech Ltd, Reading, United Kingdom

1. Abstract The provision of adequate and reliable supply of utilities (fuel, steam and power) represents a significant operating cost for many industrial companies. Refinery, petrochemical and utility companies can address the key issues associated with the purchase, supply and usage of such utilities within environmental constraints through the use of a single Energy Management tool to optimise energy business processes and substantially improve financial performance (typically equivalent to 2 to 5% of total energy costs). For many industries, the energy/Utilities cost is the largest operating expense after the purchase of raw materials. Many large companies are focusing on reducing the costs of energy, and the deregulation of the energy supply market in both the USA and Europe has made “intelligent” purchasing of Utilities very important. Industrial companies have used various tools in an attempt to monitor and optimise the supply and use of energy; these include spreadsheets, monitoring and targeting, simulation and expert systems. To-date, most companies do not have a single tool that allows the economic integration of all the business processes associated with the purchase, supply and use of Utilities . This article describes a case study of an online energy management and optimisation system that has been installed at a petrochemical complex in China (Shanghai SECCO Petrochemical Co). SECCO embarked on the development of an Energy Management System (EMS) with its chosen partner AspenTech. The objective of the EMS project is to provide SECCO with an integrated advisory tool to be used by operators. The EMS is an online, open loop optimisation solution used to lower operating costs and monitor energy performance. The EMS identifies actionable cost saving opportunities in real time and empowers operators to take immediate action. This project identified significant, continuous real-time operating cost reductions. Annual benefits of >1% are being achieved.

2. Keywords: Energy Management System, Industrial Utilities, Power Plant, Optimisation, Perfomance Monitoring.

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3. Introduction 3.1. Introduction to SECCO Petrochemical Shanghai SECCO Petrochemical Co is the largest petrochemical project of joint venture in China between Sinopec (30%), SPC (20%), and BP (50%). The petrochemical site is a world-class integration based around a 1.2 MTA naphtha cracker. Chemical products produced by the firm include ethylene, propylene, polyethylene, polypropylene, styrene, polystyrene, acrylonitrile, butadiene, benzene, toluene, and byproducts. SECCO owns and operates the utility system which serves various production processes in the plant. These include; steam, electricity, fuel gas and purchased gas. 3.2. Project Objectives To manage continuous performance improvements across its utility system, SECCO embarked on the development and implementation of an online, open loop optimisation and Energy Management System. The objective is to provide an integrated production information system to support decisions in different business processes. 4 Business Goals: Reduce energy consumption and emissions.

○ Lower operating costs (Supply of utilities at lowest possible cost) ○ Online performance monitoring (CO2, equipment efficiencies, and process specific energy) 4 Project Goals: Operational excellence – selecting the best energy source to supply the process energy demands; and optimising the process energy demand

○ Deliver actionable information to operators in real time – – – –

How is energy currently being supplied What’s the best way to supply it and What needs to change Identifying the areas of excess process energy use

○ Improve operator awareness of the cost of energy 4. Utility System Model Challenges & Solutions The complexity and dynamics of energy generation and supply gives rise to large savings opportunities to companies equipped to manage their energy in real time. For SECCO this involved optimizing energy sources supplying energy (three boilers, two steam turbo-generators, and multiple steam turbine drives), evaluating the impact on utilities of the process production plan to decrease utility costs, make optimum use of or select fuels, set optimum boilers loads and power/steam generation, as well as online integrated monitoring of energy related plant data. The following items are some of the key operational challenges that were encountered and addressed during the development of the EMS project; 4 Load allocation

○ With what load should we run the boilers and turbo-generators?

Case Study – Online Energy Management and Optimisation of Utility Generation Assets on Industrial Sites

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4 Switchable Drives

○ Should we use turbines or motors on our switchable drives? 4 Fuel constraints vs Emissions trading ○ Limit on maximum daily Natural Gas import ○ Which fuel mix should be used? (C9 / C11 Fuel Oil, or Fuel Gas)

4 Process steam, fuel and power demands

○ What is the best steam header balancing strategy? 4 Utilities contracts ○ Which water treatment system is most cost effective? ○ Max power generation limited by contract not by turbine capacity The steam, fuel and power system in the EMS were modeled in Aspen Utilities Planner (Utility system modelling software based on Aspen Engineering Suite). Low cost supply of utilities is important in integrated petrochemical complexes and any calculation of utility costs should be based on actual plant measurements rather than any theoretical basis, but raw plant data does not offer sufficient reliability or consistency to enable this. For this reason a theoretical model was used, which is based on sound thermodynamic principles, and adjusted to match closely to the current operating data. At the site level, the model is the heart of the EMS, taking the raw plant measurements and using these to generate a consistent heat and material balance of the utility system. 4.1. Modelling – Technical Challenges The utility system model presents its own unique problems due to the fact that the EMS model is based on equation oriented modelling software, which needs a reasonable estimate of the solution in order to initialise the mathematical solver. The purpose of the model is to generate meaningful information on which business decisions can be soundly based, and this can only be achieved if the initialization challenges have been appropriately addressed. A utility system at any point in time will have different pieces of equipment either in use, or shutdown. This gives rise to a wide range of different model solutions and a difficult task of identifying a common starting point for initialisation. 4.2. Components of the Modelling System - Solutions 4.2.1. Data Validation 4 An analysis of the raw values to determine which equipment is in use or shutdown. 4 Erroneous measurements can be removed from the data reconciliation problem and replaced by defaults. 4 Correct selection of weighting values represents a large “tuning” effort that is done using real plant data. 4.2.2. Data Reconciliation 4 The model itself is used to reconcile the plant data. This effectively means that the model is run multiple times in order to find the solution that gives the best match (least-squares fit) to the data set passed to the model after validation. 4 A single starting point is identified, from which all known model scenarios can be solved. There is an element of trial-and-error in identifying this case.

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5. Project Delivery Methodology Implementation of the EMS at SECCO’s site consists of five phases: 4 Identify appropriate scope of application and business justification. 4 Definition of the Functional Design Specification (FDS) 4 Implementation of system on a test platform - This phase provides the following basic elements which form the foundation of the system:

○ Detailed thermodynamic model of the utility system based on actual plant measurements

○ Key Performance Indicators (KPIs) ○ Local data historian ○ User screens for viewing site performance data in real-time ○ The final step in this phase is the Functionality Acceptance Test (FAT).

4 Commissioning on clients site – Installation, followed by Site Acceptance Test (SAT); System Documentation handover and user training. 4 Application support services and post audits of system performance.

6. Commercial & Environmental Success: How has Energy Management saved money? To date, the realized benefits of the EMS solution to SECCO is a 1% reduction in total annual site energy costs. This is a recurring benefit. As an intangible benefit, the operators now have more confidence in understanding the utility implications and cost of what they do. The EMS project has enabled the online optimisation of SECCO’s utilities plant configuration. Online values of utilities consumption, representing actual specific energy consumption of the process units, are calculated, enabling energy KPIs to be monitored in real-time. The EMS recommends appropriate actions to be implemented which will decrease losses and increase component and plant efficiencies. As production efficiencies are maximized, fuel use, and thus emissions are minimized. Some of the unique solutions that were implemented to resolve challenges encountered include; 4 Supply Side - Online, open loop model of the utility system. Combines rigorous nonlinear simulation with a mixed-integer, linear-programming optimiser to provide recommendations for the optimal configuration and load for the utilities plant. Drives the utilities plan to minimum cost operation based on user-defined constraints, which can reflect multi-tier gas or electricity supply contracts, equipment availability and load limits. 4 Demand Side - Development of empirical models to predict the consumption of utilities by the process units given the actual operating conditions. 4 Greater visibility of actionable energy moves for operators and site management with hierarchical key performance indicators that direct attention to the largest opportunities for cost savings 4 Online real time calculations and models provide immediate notification of variations in demand units and utilities 4 The solution co-ordinates energy management across the entire site and was designed to optimise site-wide energy use

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7. Benefits The SECCO EMS project pushes utility energy optimisation forward by empowering SECCO personnel to make sense of their increasingly large and diverse collection of information. The EMS innovation strategy emphasizes four key components; 4 Online (Results are always visible)

○ Many Energy Management projects stop at the offline phase 4 Provide actionable information to appropriate personnel ○ Operators are the primary users (most EMS only target engineers) ○ Operational personnel: get alerts for key deviations; proactively find out energy deviations and energy saving opportunities, change operation and control based on optimum operational advice provided by EMS, and understand the energy targets of the current shift. Greater savings (energy and money) are achieved with real-time action. 4 Both supply and demand are optimised

○ Supply side running continuously for the utilities ○ Demand-side KPIs are provided at system levels

4 Project integrates several technologies:

○ Aspen Utilities On-Line Optimiser ○ Process Historian Aspen IP.21 ○ Real-time Optimiser ○ Utilizes Abnormal Situation Management Consortium display standard for operator screens to identify gaps between current and optimum values and only show actionable information to operators that are easy to find and execute. The key “innovation” in SECCO’s EMS is the ability to enable operators to make better decisions; achieved by rigorous modeling of the Utilities system and being able to transform real-time data into actionable information. The rigorous model creates the frame work to adjust the utility system as business conditions change over time. The EMS project offers the following benefits to the end user; 4 Gain better understanding of process performance and trade-offs. 4 Facilitate new investment planning and new contract evaluation using the model offline for “What if Analysis” 4 Significant, continuous real-time operating cost savings achieved. 4 Main area of savings is in optimising equipment load allocation, fuel selection in process units and optimising fuel export. 4 Other uses of models

○ Utility scheduling ○ Operator and engineer training ○ What-if analysis – New equipment or ideas- energy projects – Unexpected impacts of non-utility projects 4 Continuous operation at targeted energy use

○ Better management of complex utility systems

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