Chapter 1 - Gas Gathering Systems

1.01 - Gas Processing Overview (9 min.) Sample Lesson
1.02 - System Design & Operating Issues (16 min.)
1.03 - Flow In Pipes (14 min.)
1.04 - Optimal Pipe Diameter (10 min.)
1.05 - Operating Problems (17 min.)
1.06 - Plant Inlet Processing (16 min.) Quiz: 1.06 - Plant Inlet Processing

Chapter 2 - Plant Inlet Processing

2.01 - Two Phase Vertical Separator Design (19 min.)
2.02 - Two Phase Horizontal Separator Design (12 min.)
2.03 - Three Phase Separators (12 min.)
2.04 - Horizontal Three Phase Separators (12 min.)
2.05 - Plant Inlet Processing (6 min.) Quiz: 2.05 - Plant Inlet Processing

Chapter 3 - Compression

3.01 - Reciprocating Compressors (12 min.)
3.02 - Centrifugal Compressors (19 min.) Quiz: 3.02 - Centrifugal Compressors

Chapter 4 - Pumps

4.01 - Pump Selection (17 min.)
4.02 - Centrifugal Pumps (16 min.)
4.03 - Reciprocating Pumps (7 min.) Quiz: 4.03 - Reciprocating Pumps

Chapter 5 - Gas Treating

5.01 - Gas Processing Chemistry (20 min.)
5.02 - Gas Sweetening (Part 1) (13 min.)
5.03 - Gas Sweetening (Part 2) (7 min.)
5.04 - Gas Sweetening (Part 3) (11 min.)
5.05 - Gas Sweetening Operating Problems (14 min.)
5.06 - Metal Cracking & Foaming (14 min.)
5.07 - Solution Degradation & Testing (11 min.)
5.08 - Physical Solvents & Alternate Processes (6 min.)
5.09 - Dry Processes (10 min.)
5.10 - Gas Sweetening Calculations (5 min.) Quiz: 5.10 - Gas Sweetening Calculations

Chapter 6 - Gas Dehydration

6.01 - Gas Dehydration: Purpose & Process (16 min.)
6.02 - Gas Hydrate Estimation (7 min.)
6.03 - Gas Dehydration Methods (15 min.)
6.04 - Gas Dehydration Operating Problems (10 min.)
6.05 - Liquid Desiccant Absorption (18 min.)
6.06 - Liquid Desiccant Absorption Operating Problems (25 min.)
6.07 - Gas Dehydration Regen Processes (12 min.)
6.08 - Gas Dehydration Desiccants (11 min.) Quiz: 6.08 - Gas Dehydration Desiccants

Chapter 7 - Hydrocarbon Dew Point Control & Liquid Recovery

7.01 - Hydrocarbon Liquid Recovery - Overview (11 min.)
7.02 - Economizer Refrigeration Cycle (17 min.)
7.03 - Heating/Cooling Curves (8 min.)
7.04 - Refrigeration Plant Design (21 min.)
7.05 - Silica Gel Plants (4 min.)
7.06 - Lean Oil Plants (9 min.)
7.07 - Turbo Expander Plants (33 min.)
7.08 - Process Selection (12 min.)
7.09 - Fractionation (16 min.)
7.10 - Reflux & Reboiling (16 min.) Quiz: 7.10 - Reflux & Reboiling

Chapter 8 - Sulphur Recovery

8.01 - Sulphur Recovery Processes (25 min.)
8.02 - Variations On The Claus Process (10 min.)
8.03 - Reheating Methods (7 min.)
8.04 - COS & CS2 (24 min.)
8.05 - Operation & Control (20 min.)
8.06 - Sulphur Recovery Enhancements (7 min.) Quiz: 8.06 - Sulphur Recovery Enhancements

Chapter 9 - Acid Gas Injection

9.01 - Acid Gas Injection - Why Consider It? (34 min.)
9.02 - Design Considerations (9 min.) Quiz: 9.02 - Design Considerations

Gas Processing Surface Facilities / Chapter 1 - Gas Gathering Systems

Lesson 1.01 - Gas Processing Overview

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Transcript

01. Lesson 1.01: Gas Processing Overview 02. Processing 03. Why Process?04. Why Specifications?05. Why Specifications? (2)06. Processing Types 07. Plant Processing Description

01. Lesson 1.01: Gas Processing Overview

Hi everybody. Welcome to Gas Processing 101. I'm Wayne Monnery. And as the name implies, we're going to be talking about gas processing. We're going to go through the whole thing, from wellhead to front of the plant, from the front of the plant to the back of the plant. We will not be covering any subsurface material. There are plenty of courses, some available from Richard Baker to discuss subsurface materials. So we're going to stay on the surface, but thanks for attending this. And you're going to find that even though it is gas processing, lots of the material is kind of generic, which means some of the things you learn will be applicable to the oil side of the business, for example, though there will be a separate course coming with oil facilities.

02. Processing

So, let's start with processing.

03. Why Process?

Why do we process? First question. Well, we process to meet specifications: sales gas specifications and liquid specifications. What are sales gas specifications? Well, first of all, we have a water content or dewpoint specification. And it's not worldwide, but in Alberta it's typically 4 lb/MMscf water content, which is about 64 mg/m³. And that's about the same as a water dewpoint of 15 °F or -10 °C at typical pipeline pressure. What does that do? Well, it prevents water from condensing out in the pipeline. And you're also going to find that takes care of hydrates for you. We also have a typical hydrocarbon dewpoint specification, which is similar: 14 °F or -10 °C at pipeline pressure. And so that takes care of making sure that you don't condense any heavier hydrocarbons out.
What other kinds of specifications are there? Well, we've got things for safety and corrosion. H₂S somewhere between 4 and 16 ppm. There's also usually a total sulfur specification, and the values for that depend on the pipeline itself. Carbon dioxide: we have a 2 vol% specification. There's heating values, and these are gross heating values typically on your contract. And that's about 36 - 37 MJ/m³.
There are also liquid specifications, as I mentioned. It depends on the liquid that you're actually producing but NGL, for example, a typical specification is a 2 vol% C₂/C₃. So what that does is that ensures that your propane will never have more than 2 vol% ethane in it. There are other specifications for other types of liquids, for example, hydrocarboncondensate. And we used to have a butane specification of less than 5 vol%. Now, as you can see on this slide, it's actually 3 × (methane + ethane + propane) and then adding that butane, they all have to be less than 5 vol%.
There's typically also some kind of vapor pressure specification, like some kind of Reid vapor pressure equivalent or something like that. And those types of specifications might be, let's say, a vapor pressure equivalent less than 12 psia. Notice that absolute pressure units, not gauge. And that, of course, is about 83 kPaa.
So propane specifications; it depends. But typical one might be the components on either side of it or less than 2 vol%, which would mean the propane would be 96 vol%. Quite often, there may be a vapor pressure specification. As you can see here, it might be 208. In this case, it is gauge pressure: 208 psig at 100 °F or 37.8 °C. And butane, same kind of thing, 95% - 96%. And so your propane and pentane specifications then would be 2%. And then, a lower vapor pressure specification for that something like 70 psi again, at 100 °F. Vapor pressures are often at 100 °F or 37.8 °C.

04. Why Specifications?

Why do we have these specifications anyway? Minimize corrosion, certainly. If I don't have any water coming out as liquid, I don't have corrosion. Minimize H₂S—that's a safety concern, of course, and minimize CO₂, another corrosion issue. CO₂ also has no heating value, so there's no point in having much CO₂ in your gas anyway. Again, getting back to water, avoiding gas hydrates. If you don't know what hydrates are, they are ice-like compounds, but they occur at higher than the freezing point of water or the triple point. If I don't have any water liquid, I don't have corrosion. And if I really control the water amount, like a low water dewpoint or a low water content, as we talked about in the earlier slide, then I'm not going to have a hydrate problem. We also want to keep the gas fairly dry for the markets that it's used in. So we don't want any heavier hydrocarbons in that gas. And that means minimizing liquids in the pipeline. And we do that with the hydrocarbon dewpoint specification.

05. Why Specifications? (2)

Safety—I mentioned it a couple of times. H₂S is actually toxic to humans if you breathe it in. So we're going to minimize the H₂S and maximize the heating value. So we limit CO₂. We also limit things like nitrogen because it has no heating value either. The nitrogen specification might be a total inert specification, or it might be an actual nitrogen specification.

06. Processing Types

Let's move on to processing types. There's actual gathering. And that is, of course, the gathering pipeline. There can be field processing. We don't do a whole lot out in the field, but there might be dehydration and compression. There's plant processing, and that'll be at some kind of central location. And that's where we do a lot of the processing on the surface. So for sweet gases, we would typically have dehydration of some kind, hydrocarbon dewpoint control, any kind of liquid product stabilization, no matter what liquid we make. And when we say stabilization, what we're really talking about is making sure that we don't have any volatile components that are going to come off as vapor from a typical storage. For sour gases, we would have the same types of processes, plus we would have to treat or sweeten the sour gas to remove the H₂S and/or CO₂. Some plants have fractionation. And that's where we're splitting those mixed liquids like NGL or hydrocarbon condensate into their fractions like propane, butane, etc.

07. Plant Processing Description

Here's a block flow diagram that kind of shows what I just explained. You've got an inlet gas starting at the left. Just going to see if I can bring up our laser pointer, and that way I can show you. So here's your inlet gas coming in. First thing we would do is go through inlet separation because what we want to do there is do any phase separation. We can come in off the pipeline. And so you're going to have potentially 2 liquid phases coming. There's going to be a hydrocarbon liquid phase and a water phase. And then, you'd have your gas phase. If we follow the gas and it's sour, then we would have to have a sweetening and regeneration block right here. Once I remove the H₂S and CO₂, that's now acid gas that's coming off. And that's actually going to go to a flare if I had a low enough amount sulfur recovery, which for many years we didn't do because the sulfur price was kind of in the basement. But sulfur price actually has come back with alternative energy sources. So more people are paying attention to their old sulfur plants or even putting some new ones in.
Or it can go to acid gas injection. Once we have sweet gas down here, we can go over to some kind of dehydration. So water removal there. Once it's water dry, then I would have hydrocarbon dewpoint control. Now, you're going to see in this course that this block for dehydration and this one for hydrocarbon dewpoint control are often the same block. In other words, we can do both the water removal and the hydrocarbon liquid removal in the same block. After that, I would have sales gas quality—gas, which can be used for sales and fuels. If I now follow the hydrocarbon liquid, it's going to go over to some kind of stabilization, as we mentioned earlier, which applies to any kind of mixed liquid product. Water, of course, goes to storage and ultimately to disposal. And I can have that coming off the front end of the plant or off whatever dehydration technique I'm using.
OK, that's the first lesson. And we're going to go on to gas gathering in a moment.