Lab Schedule

Terry A. Ring Chemical Engineering University of Utah Trouble Shooting Terry A. Ring Chemical Engineering University of Utah 1) The steam trap is blocked causing liquid condensate to back up in the heat exchanger so the steam does not contact the pipes in the exchanger. 2) The entering water is sub-cooled. 3) The steam pressure and temperature have dropped. 4) The heat exchanger has become fouled. 5) The steam is dirty, i.e., contains non condensable gases.

What is Trouble Shooting Problem solving process to find the root cause of a problem so it can be fixed. Trouble Shooting is not an exact science. Requires Paying attention to detail, good listening, understanding symptoms, viewing problem first hand

Try to Solve this problem QUESTION FROM TROUBLE ANSWER FROM EXPERTS COST TO ANSWER SHOOTERS Steam Pressure at PlOO? Higher Than Design. 5 min. Steam Temperature at TIOO? Design Value. 5 min. Amount of Condensate Drainable from Tubes Via the Bypass Valve? About 0.5 Pints of Condensate. 30 min. Feedwater Exit Temperature After 10 min. of Bleeding? 68 Degrees Celsius. 40 min (120 min. if Drain Valve Already Opened) Feedwater Exit Temperature After Bleeding Pipes? 3 Hours 45 Degrees Celsius. 3 Hours.   Bleed Gas Analysis Results. 20% Air. 2% Carbon Dioxide, Traces of Oil. 8 Hours. Action Cost Read meter 2 min. Check History 5 min Make Manual Measurement 30 min Adjust Operating Conditions 30 min Disassemble Equipment 4 hr Install new Equipment 5 day

Costs for Analysis Action Cost Read meter 2 min. Check History 5 min Make Manual Measurement 30 min Adjust Operating Conditions 30 min Disassemble Equipment 4 hr Install new Equipment 5 day

Guidelines

Critical Thinking and Trouble Shooting Kepner-Tregoe (K-T) Strategy Clearly determine what is the problem Classification of problem into Do we need to determine the cause of the problem Do we need to make a decision on the problem Do we need to plan to avoid future problems Develop multiple approaches simultaneously Establish probability for success (and cost) of each approach before proceeding Know what a potential response to a question will be under various problem scenarios.

Socratic Questioning Questions for Clarification Was the pump on when you heard the bang? Questions that probe assumptions Why did you assume that the white material in the pipe was calcium carbonate? Questions that probe reasons or evidence What is a past example that shows the same phenomenon? What is the reason you think that is true? Questions about viewpoint & perspective Where were you when you heard the bang? Where in the car is the squeak coming from? Questions that probe implications & consequences Did you see smoke before the compressor seized up? Questions about the question Why did you ask the question, was it raining when the compressor seized up?

Kepner-Tregoe (K-T) Strategy

When asking question or asking for analysis What will I learn if I ask this question? How will I use this information to find the fault? Keep 4 or 5 working hypotheses at any one time.

K-T Analysis

K-T Potential Problem Analysis Possible Cause Preventive Action Contingency Plan A. 1. 2. B.

Try to Solve this problem 1) The steam trap is blocked causing liquid condensate to back up in the heat exchanger so the steam does not contact the pipes in the exchanger. Heat transfer coefficient is less in this case. 2) The entering water is sub-cooled. 3) The steam pressure and temperature have dropped. 4) The heat exchanger has become fouled. 5) The steam is dirty, i.e., contains non condensable gases.

K-T Analysis

Possible Faults with Similar Behavior 1) The steam trap is blocked causing liquid condensate to back up in the heat exchanger so the steam does not contact the pipes in the exchanger. 2) The entering water is sub-cooled. 3) The steam pressure and temperature have dropped. 4) The heat exchanger has become fouled. 5) The steam is dirty, i.e., contains non condensable gases.