OVERVIEW
This unit is designed to teach trainees the basics of using SPC to monitor and control distilla­tion processes. After completing this unit, trainees should be able to identify general causes of variation in distillation processes. Trainees should also be able to recognize trends, runs, warning line violations, control limit violations, cycling, and overcontrol on control charts. In addition, they should be able to identify possible causes of these conditions and respond to them. 

OBJECTIVES

Introduction

·          Identify reasons for using SPC in distillation processes and identify types of equipment commonly used in a distillation process.

·          Describe types of control charts used in distillation processes and explain how the values plotted on control charts are normally determined.

Causes of Variation in Distillation Processes

·          Describe how SPC charts indicate, normal or random, variation in distilla­tion processes.

·          Describe patterns on SPC charts that indicate assignable, or special causes, of variation in distillation processes.

·          List typical assignable, or special, causes of variation in distillation pro­cesses.

Trend Indications

·          Describe how to detect a trend or run on a control chart and how to respond to the trend.

Warning Line Violations

·          Describe how to detect a warning line violation on a control chart and how to respond to it.

Control Limit Violations

·          Describe how to detect and respond to a control limit violation on a control chart.

·          Identify causes of control limit violations in distillation processes.

Cycling and Overcontrol

·          Describe how to detect cycling on a control chart.

·          Identify common causes of cycling in a distillation process.

·          Describe how to detect overcontrol of a distillation tower from an SPC chart.

·          Identify factors that affect a distillation tower's response time.

SUBJECTS

Introduction

·         Reasons for using SPC in distillation processes

·         Distillation equipment

·         SPC control charts

·         Collecting data for control charts

Causes of Variation in Distillation Processes

·         Random variation in distillation

·         Guidelines for identifying special cause variations

o        Trends and runs

o        Control limit violations

o        Warning line violations

o        Cycling

o        Other special cause guidelines

·         Special causes of variations in distillation processes

o        Feed

o        Heating and cooling

o        Rotating equipment

o        Tower operation

o        Weather

Trend Indications

·         Collecting and plotting data

·         Detecting a trend

·         Responding to a trend

Warning Line Violations

·         Collecting and plotting data

·         Detecting a warning line violation

·         Responding to a warning line violation

Control Limit Violations

·         Detecting and responding to a control limit violation

o        Cooling tower example

o        Preheater example

·         Causes of control limit violations

Cycling and Overcontrol

·         Cycling

·         Overcontrol

·         Response time