ADVANCED PROCESS CONTROL (APC)
Sulphur recovery unit is a familiar process in modern refineries, gas plants and petrochemical plants. APC technology is applied for improving and optimising the sulphur cycle operations including amine treating, sour water strippers, sulphur recovery (Claus), tailgas treatment and incinerators.
Comprehensive hardware and software package consisting of both conventional control technology and multivariable control technology (MVC). Hardware is based on a computer process control IBM compatible that communicate with DCS. MCV is based on AspenTech DMC Plus package. APC is developed and implemented in Control Modules. Each APC Module is dedicated to control different sections of the plant. APC is applicable on either new or existing sulphur plants.
The SRU receives acid gas from the amine regenerator units and from the sour water strippers. The H2S in the inlet flows are converted in elemental sulphur, normally through partial oxidation with air. Tailgas from SRU are usually further treated in a tail gas clean up unit (TGCU) to remove the residual H2S and to enhance the recovery efficiency. Main goals of the APC modules are the following:
- Maximisation of sulphur recovery efficiency
- Plant management under normal and upset conditions
- Management of load changes both in terms of acid gas flow and composition
- Reduction of energy consumption and chemical wastes
- Minimisation of pollutants emission to the atmosphere
The above goals are achieved by applying the following dedicated APC modules:
- Amine absorber module provides amine flow rate optimisation and lean amine temperature optimisation
- Amine regeneration and sour water stripper modules provide steam consumption minimisation, acid gas quality control and feed flow rate stabilisation
- Sulphur plant and TGCU modules provide tail gas quality control, converters temperature optimisation, hydrogen consumption minimisation, reducing reactor temperature control and amine flowrate optimisation
- Incinerator module provides incinerator temperature control.