May 25, 2024

Flow Computers: Introduction

Flow computers have become an essential part of hydrocarbon measurement and flow metering systems. They play a key role in operations across oil and gas, chemical and other process industries.

What is a Flow Computer?

A flow computer is a specialized microprocessor-based electronic device which acts as the central processing and data logging center for an entire flow metering and measurement system. Flow computers typically have multiple input channels which can connect to various flow meters, temperature and pressure transmitters in the pipe or process. They accept the raw signals from these instruments, perform engineering calculations and convert the data into totalized or tabulated flow quantities.

Hardware Configuration

A typical flow computer consists of the following key hardware components:

– Central Processing Unit (CPU): The brain of the flow computer which performs all measurement, logging and control functions. This is usually a microprocessor or microcontroller chip.

– Memory: Flow computers have various types of memory like RAM, Flash/ROM to store operational software, configuration data and measurement records. Larger memory allows storing data for extended periods.

– Communication Ports: These allow connecting flow meters, instruments as well as communicating with host systems via protocols like Ethernet, Wireless, Modbus, HART etc.

– Display: Basic flow computers may have a LCD screen while advanced models have full color displays for viewing data onsite.

– Enclosures: Industrial enclosures protect the electronics from extremes of weather, vibration and hazardous environments. Different enclosure types (Wall mount, DIN-rail, NEMA) are available.

– Battery/Power Supply: Flow computers require a stable power source which can be supplied from batteries, solar panels or regular power lines depending on the installation location.

Software and Measurement Functions

The real power of a flow computer lies in its sophisticated measurement software. Advanced models perform:

– Sensor Linearization: This corrects for any non-linearity errors in the primary elements like orifice plates and transmitters.

– Differential Pressure and Temperature Compensation: Changes in process fluid properties due to pressure and temperature fluctuations are automatically compensated.

– Volume and Mass Calculation: Flow rates can be totalized or logged as standard or mass volume depending on requirements.

– Gas Compensation: For gas flow, parameters like compressibility,super-compressibility and Real Gas calculations are supported.

– Cutting Edge Algorithms: Flow computers utilize the latest ISO, AGA and API measurement standards and equations for highest accuracy.

– Data Logging: Configurable logging intervals from seconds to days allow long term archival of flow data on internal memory or external host.

Communications and Data Export

Flow computers provide multiple options to transfer valuable flow data to host systems:

– Serial Communications: Standard serial ports along with protocols like Modbus RTU allow host connectivity via simple multi-drop wiring.

– Fieldbus: Fieldbuses like Foundation Fieldbus H1, PROFIBUS PA extend communications capability in process control environments.

– Ethernet/Wireless: Networking technologies enable remote connectivity via LAN/WAN or wireless for real-time access from control rooms.

– Meter Data Management Systems (MDMS): Flow computers can directly interface with MDMS/SCADA for automatic data upload to central databases.

– Mass Storage Devices: Alternatively, data can be retrieved periodically by physically accessing the flow computer’s memory card/USB port.

Applications in Industries

Due to accurate and reliable flow measurement capabilities, flow computers find widespread adoption:

Oil & Gas
– Custody transfer of petroleum products between operators
– Well testing, allocation and production accounting
– Pipeline monitoring

Petrochemical
– Refineries – Feed and product measurement
– Petrochem plants – Reactor and reactor product measurement

Water/Waste Water
– Water distribution networks
– Sewage and wastewater treatment plants

Gas Distribution
– Natural gas sales and transportation
– City gate stations
– Industrial bulk gas deliveries

Power Generation
– Fuel and ash flow measurement at coal, gas and hydro power facilities

Selection Considerations

When selecting a flow computer, factors to evaluate include:

– Required measurement accuracy as per industry standards
– Number of input channels and supported meter types
– Application environment conditions like temperature, vibration etc.
– Desired communications options and data export facilities
– Lifecycle operating costs including maintenance and support
– Manufacturer quality, reliability and local service network

Modern flow computers have evolved into all-in-one measuring systems delivering reliability, flexibility and overall cost effectiveness. They continue driving efficiency across process industries by enabling accurate monitoring and accounting of critical flow streams. With advanced capabilities, flow computers will remain indispensable for complex measurement applications of the future.

 

 

*Note:

  1. Source: Coherent Market Insights, Public sources, Desk research
  2. We have leveraged AI tools to mine information and compile it