Profit Maximization Techniques for Operating Chemical Plants. Sandip K. Lahiri

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Figure 3.1 Different steps in profit maximization project (PMP) implementation

      3.1.3 Step 3: Assessment of the Base Control Layer of the Plant

      The regulatory proportional, integral, and derivative (PID) control loop forms the base layer of a control system. It is of the utmost importance to assess the performance of the base control layer and improve upon it before trying to build a PMP application over it. In this step an overall assessment of the base control layer was performed scientifically and corrective steps were taken to rectify limitations, if any. This essentially means identification of any problems in control valves (like hysteresis, stiction, valve oversize, or undersize phenomena), measuring sensors (like noise, range of instruments, calibration, etc.), PID controller tuning, oscillation in process parameters, etc., and application of various techniques like controller tuning, maintenance of control valves, calibration of instruments, etc., to rectify the problems (Lahiri, 2017a). Enhancement of control performance actually reduces the variations in key economic parameters of a process and then the DCS panel engineer is able to push the process further near to its constraints. Using only this step, a 1–5% increase in profit has been reported in various literatures by various global chemical companies.

      3.1.4 Step 4: Assessment of Loss from the Plant

What are the major energy and product losses in a process? This is the first question that people should ask before embarking on a significant effort to improve profit. The answer to this question could lead to identification of major improvement opportunities and help to define the need for a large profit improvement effort. In a chemical process, a valuable product can be lost either with wastewater or vent to flare. In this step, a systematic approach is followed to calculate how much money gets lost in USD/h terms due to waste and vent. Not only product loss, but also energy loss, account for a major erosion of profit in many chemical plants. In a process, energy losses consist of both thermal and mechanical losses (Zhu, 2013). Thermal losses typically originate from column overhead condensers, product rundown coolers, furnace stack, steam leaks, poor insulation of heat exchangers/piping and vessels, and so on. Mechanical losses could also be significant, which usually occurs in rotating equipment, pressure letdown valves, control valves, pump spill back, heat exchangers, pipelines, and so on. Some of the wastewater, vent gas to flare, and thermal and mechanical losses are recoverable with a decent payback of investment, but many others do not. An energy and product loss audit seeks to identify key recoverable losses. The audit is relatively quick and is designed to determine improvement potential. If the energy loss audit identifies large energy or product losses, more detailed energy assessment efforts will be undertaken later if so required. After identifying all the product and energy losses in a chemical complex, small improvement projects can be initiated and implemented to stop or reduce these losses. In this way, by reducing the money drain from plants, profit can be increased. Many companies in the world have been able to increase their profit 1–5% by following this simple but effective step.

      3.1.5 Step 5: Identification of Improvement Opportunity in Plant and Functional Design of PMP Applications

      Before building a PMP application for a process, the concerned chemical engineer must understand all the relevant aspects of the process, its various limitations, how it makes profit, and what area can be exploited to increase profit. As a starting step, the PMP engineer usually surveys PFDs and P&IDs of the process under study, meets with operations engineers and a specialized work force, and finds all the opportunities and constraints to increase profit in a plant. In this step the PMP engineer usually assesses the current operation, analyzes historical data, understands the various safety and process constraints and equipment limitations, etc. A functional design aims to identify all the existing opportunities to increase the plant profit (Lahiri, 2017c). In this step, the PMP engineer formulates various profit improvement strategies and identifies all potential applications where application of data analytics and modeling and optimization techniques can be applied to improve profit. A preliminary feasibility study is undertaken to identify whether an APC application can be implemented. In this step, an overall idea and forward path is made regarding which PMP application will be used and where to tap into the profit increase opportunity. A functional design step basically provides a map of every opportunity and which methods will be used to exploit a particular opportunity. The success of the profit maximization will greatly depend on how the functional design is formulated in order to tap into the potential margins available in the process. This step requires synergy between expertise and experience of the domain engineer or plant process engineer and the PMP engineer.

      3.1.6 Step 6: Develop an Advance Process Monitoring Framework by Applying the Latest Data Analytics Tools

The most important step in developing a profit management solution to optimize a process is to be able to measure what process performance looks like against a reasonable set of benchmarks. This involves capturing process performance and relevant cost data related to the process and organizing it in a way that allows operations to quickly identify where the big cost consumers are and how well they are doing against a consumption cost target that reflects the current operations. Only then it is possible to do some analysis to determine the cause of deviations from a target and take appropriate remedial action. For this purpose, the concept of key profit indicators is introduced (Zhu, 2013). In this step, a dashboard is prepared for a monitoring purpose where all the key profit indicators along with their target values are shown in real‐time. This dashboard enables an operation engineer to quickly identify any deviations of cost performance of the process and take necessary preventive and corrective actions. In this step an advance process monitoring system is developed by using latest data analytics, like clustering, fault tree, a cause and effect diagram, artificial neural network, etc. This monitoring framework helps to visualize the whole process and its performance against targets and quickly highlights any deviations of performance or improvement opportunities.

      3.1.7 Step 7: Develop a Real‐Time Fault Diagnosis System

      Disruption of whole operations due to malfunctions of various process equipment is very common in chemical plants. In the worst case, due to malfunction of compressors, СКАЧАТЬ