Knowledge for the Sulphuric Acid Industry
Sulphuric Acid on the Web
Introduction
General
Equipment Suppliers
Contractor
Instrumentation
Industry News
Maintenance
Acid
Traders
Organizations
Fabricators
Conferences
Used
Plants
Intellectual
Propoerty
Acid
Plant Database
Market
Information
Library
Technical Manual
Introduction
General
Definitions
Instrumentation
Plant Safety
Metallurgial
Processes
Metallurgical
Sulphur Burning
Acid Regeneration
Lead Chamber
Technology
Gas Cleaning
Contact
Strong Acid
Acid Storage
Loading/Unloading
Transportation
Sulphur
Systems
Liquid SO2
Boiler Feed Water
Steam Systems
Cooling Water
Effluent Treatment
Utilities
Construction
Maintenance
Inspection
Analytical Procedures
Materials of Construction
Corrosion
Properties
Vendor Data
DKL Engineering, Inc.
Handbook of Sulphuric Acid Manufacturing
Order
Form
Preface
Contents
Feedback
Sulphuric Acid
Decolourization
Order Form
Preface
Table of Contents
Process Engineering Data Sheets - PEDS
Order
Form
Table of Contents
Introduction
Bibliography of Sulphuric Acid Technology
Order Form
Preface
Contents
Contact Section -
Blowers
- Specification
April 25, 2004
Introduction Capacity Normal Design Flow Minimum Flow Overdesign Corrosion Allowance Critical Speeds Materials of Construction Tests Applicable Standards |
Associated Links |
The main blower is one of the single most expensive pieces of equipment in a sulphuric acid plant. To ensure that the main blower will operate trouble free and at the intended capacity it must be specified properly from the very beginning in terms of the process and mechanical design criteria.
The capacity of the blower is determined by the amount of gas or air that must be handled to achieve the production rate of the plant. The capacity of the blower should allow for the normal design flow as well as the minimum flow requirements.
Normal Design Flow
The normal design flow will be the flow rate required to achieve the plant production requirements.
Minimum Flow
The minimum flow through the blower is generally set by the preheat requirements of the acid plant. In some cases, the process requirements of the plant may dictate the minimum flow but this is unusual. During preheating air is heated in the preheat system and is used to preheat the converter and catalyst to the minimum strike temperature of the catalyst. The flow requirements are set by the time required to preheat the plant which is generally 24 to 36 hours. To achieve this requirement a flow rate of 30 to 40% of the normal design flow is required.
Overdesign
An overdesign will generally be specified for the blower as a safety margin to ensure the plant can achieve its design production rate. Typically, and overdesign of 5% of the normal design flow is specified. In some cases the overdesign may be as high as 10% depending on design requirements specified by the plant operator.
A corrosion allowance of 3 mm (1/8”) is generally specified for the casing.
API Standard 617 defines critical speeds as:
“Critical speeds correspond to resonant frequencies of the rotor-bearing support system. The basic identification of critical speeds is made from the natural frequency of the system and of the forcing phenomena. If the frequency of any harmonic component of a periodic forcing phenomena is equal to, or approximates, the frequency of any mode of rotor vibration, a condition of resonance is may exist; if resonance exists at a finite speed, that speed is called a critical speed.”
Blowers should be designed so that there are no critical speeds within the normal operating range of the blower.
The materials of construction for the blower should be suitable for the service conditions and gas being handled.
Casing (Castings) | Grey Cast Iron (GG25) (DIN 0.6025) Cast Iron (A40 40B) Cast Iron (A278 Class 40) |
Shaft | 17CrNiMo6 Alloy Steel |
Shaft Sleeve | 316 SS |
Shaft Bushing | X35CrMo17 (DIN 1.4122) A511 Mt 440 A |
Impeller - Blades | AISI 4130 StE 460 (1.8905/A572 Grade 65) X 5 CrNi 13 4 (DIN 1.4313) |
Impeller - Hub | StE 500 (1.8907/A514 Type A-P) X 5 CrNi 13 4 (DIN 1.4313) |
Inlet Guide Vanes - Housing | Grey Cast Iron (GG25) (DIN 0.6025) Cast Iron (A40 40B) |
Inlet Guide Vanes - Vanes | X 6CrNiMoTi 17122 (DIN 1.4571) Cast 316L SS |
Base Frame | RSt 37-2 (DIN 1.0038) A284 Grade B |
Oil Reservoir | RSt 37-2 (DIN 1.0038) A284 Grade B |
Oil Piping - Upstream of Filters | Carbon Steel (A53 Grade A) |
Oil Piping - Downstream of Filters | X6CrNiTi1810/X6CrNiMoTi 17122
(1.4541/1.4571) A276 Type 321/AISI Type 316 304 SS |
The following tests are generally performed during the manufacture and testing of the blower.
Hydrostatic pressure test of the compressor casing
Dynamic balance of the rotating element at reduced speed
Mechanical running test with shop driver at full speed and reduced load
Impeller overspeed test during mechanical running test at 115% speed
|
|
The following standards are generally applied to the design, fabrication and testing of a blower for acid plant service.
AGMA 6011-H98 | Association of Gear Manufacturers Specification for High Speed Helical Gear Units (formerly AGMA 421) |
API Standard 614 | Lubrication, Shaft-Sealing, and Control Oil Systems for Special-Purpose Applications |
API Standard 617 | Centrifugal Compressors for General Refinery Service |
API Standard 670 | Noncontacting Vibration and Axial Position Monitoring Systems |
ISO 5389 | Turbocompressor Performance Test Code (replaces VDI 2045) |
ISO 8011 | Turbocompressor Design and Construction |
ISO 10817 | Shaft Vibration for Industrial Turbosets – Measurement and Evaluation (replaces VDI 2059) |
DIN ISO 1940 | Shaft Vibration for Industrial Turbosets – Balancing (replaces VDI 2060) |
DIN 4312 | Steam Turbine Design and Construction |
VDI 2056 | Verein Deutscher Ingenieure Evaluation Criteria for Mechanical Oscillations of Machines |