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ASME PTC 16-1958 (1971) — Test Code for Gas Producers and Continuous Gas Generators
🔥 ASME PTC 16-1958 (1971) is the ASME Power Test Code for gas producers and continuous gas generators. Its lineage goes back to a preliminary test code published in 1924; the revised edition was adopted in 1958 and reaffirmed in 1971. The Code establishes rules for conducting tests to determine the operating characteristics of gas producers, covering all continuous types — large and small — including those using fixed beds, fluidized beds, pulverized fuels, oxygen, recycled CO₂ gas, and externally heated retorts. It applies to units that continuously generate gas primarily composed of carbon monoxide and hydrogen from solid or liquid fuels for power, heating, or chemical purposes.
💡 PTC 16 is the “test language” of producer-gas plants: it standardizes fuel metering, gas sampling, calorific values, and material balances so that results from different plants and different producer designs can be compared. Although dated, its heat-balance framework remains the basis of performance evaluation for gasification units today.
1. Object and Scope 📌
The Code defines a gas producer as any unit which generates primarily CO or H₂ continuously from solid or liquid fuels. The term “fuel” covers all carbonaceous solid and liquid fuels — coals, coke, charcoal, refuse, lignites, peats, woods, and oils. Continuous producers of all sizes are included regardless of whether they use fluidized beds, pulverized fuels, fixed beds, oxygen, recycled CO₂, or externally heated retorts; cyclically operated generators similar to those used in water-gas generation are excluded. Possible test objectives include:
- The maximum capacity of the producer plant and each of its auxiliaries;
- The efficiency of the producer in making gas and the performance of each of its components;
- The ability of the producer to use a specific fuel and to respond to varying loads;
- The quantity, quality, and cleanliness of the gas;
- The results obtained by using different kinds and sizes of fuels in different ways;
- The amounts and costs of labor and power required to operate the producer and its auxiliaries;
- The reliability of the producer and its parts, the causes of faulty operation, and the efficiency of recovery of by-products such as ammonia.
⚠️ The scope of the test must be defined in advance: whether auxiliaries are included, which producer is the test object, and whether the objective is single or multiple. Test different unit types or capacities separately — overall results from a plant with mixed units give no indication of any individual unit’s performance.
2. Description and Definition of Terms 📖
Section 2 provides a table of definitions; the principal terms are summarized below:
| Term | Description |
|---|---|
| Fuel feed | The amount of fuel feed, either solid or liquid |
| Higher heat value (gross) | Heat given out during combustion with equal initial and final temperatures, including the latent heat of any condensed water vapor |
| Lower heat value (net) | The same, after deduction for the latent heat of water vapor |
| Temperature | Gas or material temperature at each measuring point |
| Pressure | Pressure at points in the producer and gas system |
| Moisture content | Moisture content of the fuel or gas |
| Average load factor | Ratio of average load during the test to rated load |
| Hot gas output | Quantity and calorific value of the hot gas delivered |
The Code uses 60°F and 30 in. Hg, dry basis as the reference state — a deliberate choice made by the PTC 16 Committee to align with the manufactured-gas industry standard, and differing from the values in the Code on Definitions and Values. Figure 1 provides a flow sheet of a producer-gas plant; Figure 2 provides the complete heat-flow diagram covering sensible and latent heat of the gas, the heat of tar, heat of refuse and dust, heat removed by cooling water, radiation loss, and heat unaccounted for.
3. Guiding Principles and Preparation 🛠️
Section 3 sets out guiding principles: prepare a detailed test plan before starting, including fuel sampling and analysis, gas sampling and metering methods, and separate records of fuel, water, power, and labor for the producer and each auxiliary. The equipment shall be operated stably by the prescribed methods during the test, and starting and stopping shall be recorded separately. Section 4 covers instruments and apparatus, including checklists of instruments and measurements for fuel, gas, refuse, water, and steam, with specific directions for each measurement.
💡 Refuse and dust are easily overlooked items in a producer test: the carbon carried out in the ash is a significant heat loss. Collect and weigh the refuse, tar, and dust completely and analyze carbon content, otherwise the gas efficiency cannot be determined correctly.
4. Computation of Results and Heat Balance 📊
Section 5 defines the computation of results, centered on a complete heat balance per the heat-flow diagram:
- Inputs: latent heat of the fuel (higher or lower heat value basis) plus sensible heat, and heat brought in by air and steam;
- Outputs: latent and sensible heat of the clean gas, heat of water vapor in the gas (evaporated moisture and steam made), latent and sensible heat of tar, latent and sensible heat of refuse and dust, heat removed by cooling water, radiation and convection losses, and heat unaccounted for;
- Gas efficiency: ratio of net clean-gas output heat to fuel input heat, computed on either the higher or lower heat value basis;
- By-product recovery: recovered ammonia and similar products credited to output.
The heat balance localizes efficiency losses: an excessive “heat unaccounted for” indicates metering or sampling problems and calls for rechecking fuel, gas, and refuse analyses. Section 6 specifies the test report: equipment description, test conditions, fuel and gas analyses, metering records, the heat-balance table, computed results, and conclusions.
🚨 Representativeness of gas sampling and metering determines success: producer gas contains tar and dust; take samples downstream of cleaning where flow is stable, keep the sample system heated to prevent tar condensation, and correct results to a dry basis. Otherwise gas composition and calorific-value calculations develop systematic errors.
5. Engineering Practice Essentials 🛠️
- 🔍 Test duration: follow the Code’s duration requirements so the test covers the complete fuel-to-gas process and the bed inventory stabilizes;
- 🔧 Material balance: weigh and sample feed, ash, tar, and dust item by item to close the carbon balance;
- 📊 Load response: to evaluate load response, schedule stable operating periods at different load levels and record them separately;
- 📋 Reference state: correct all gas volumes, air quantities, and efficiencies to 60°F, 30 in. Hg, dry basis, and state the basis in the report.
6. Frequently Asked Questions ❓
❓ Q: How does PTC 16 relate to later gasification performance test methods?
A: PTC 16 was the first systematized test code for producer gas. Its heat-balance framework, fuel and gas analysis methods, and reference-state corrections were inherited by modern gasification performance evaluation and remain essential background for energy balances of gasification plants.
A: PTC 16 was the first systematized test code for producer gas. Its heat-balance framework, fuel and gas analysis methods, and reference-state corrections were inherited by modern gasification performance evaluation and remain essential background for energy balances of gasification plants.
❓ Q: Why does the Code use 60°F and 30 in. Hg as the reference state?
A: This was a unanimous decision of PTC Committee No. 16 to align with the manufactured-gas industry, which operates on a 60°F / 30 in. Hg standard, and most references in the field use the same datum; the Code uses the dry rather than the saturated basis.
A: This was a unanimous decision of PTC Committee No. 16 to align with the manufactured-gas industry, which operates on a 60°F / 30 in. Hg standard, and most references in the field use the same datum; the Code uses the dry rather than the saturated basis.
❓ Q: What is the difference between higher- and lower-heat-value efficiencies?
A: The higher (gross) basis includes the latent heat of condensed water vapor and gives lower efficiency numbers; the lower (net) basis deducts it and gives higher numbers. Always state the basis used and convert to a common basis when comparing units or reports.
A: The higher (gross) basis includes the latent heat of condensed water vapor and gives lower efficiency numbers; the lower (net) basis deducts it and gives higher numbers. Always state the basis used and convert to a common basis when comparing units or reports.
🔍 Q: What should be done when “heat unaccounted for” is large?
A: A large unaccounted item usually means missing metering or sampling. Recheck fuel feed quantity, gas flow, refuse carbon content, and tar yield to confirm all items are complete before attributing the balance to genuine radiation loss.
A: A large unaccounted item usually means missing metering or sampling. Recheck fuel feed quantity, gas flow, refuse carbon content, and tar yield to confirm all items are complete before attributing the balance to genuine radiation loss.
