IMPROVED ENERGY INTEGRATION IN AN AMMONIA PLANT

Información del proyecto

Identificador del acuerdo de subvención: EE.-00200-83

Proyecto cerrado

Fecha de inicio 1 Abril 1983

Fecha de finalización 31 Marzo 1985

Financiado con arreglo a

• Programme (EEC) of demonstration projects relating to the exploitation of alternative energy sources and to energy saving and the substitution of hydrocarbons, 1983-1985

Coste total

€ 3 572 871,00

Aportación de la UE

€ 1 429 148,00

Coordinado por

UKF Fertilisers Ltd
United Kingdom

Objetivo

To incoporate process and engineering modifications to an existing ammonia plant, thereby reducing energy consumption by 4.6% or 14,800 TOE/y, maintaining ammonia production at 950 TE/d.
The modified plant was brought back into operation in October 1984, and has been (with few exceptions) in continuous operation ever since.
The savings related to this project were to be gained in the following areas:
- charges in the CO2 removal area to reduce heat required for solution regeneration, together with the re-integration of the boiler feedwater and steam systems, result in an increased production of high pressure steam and reduction in steam raising required from the auxiliary high pressure boiler. There is therefore a fuel saving for the high pressure auxiliary boiler;
- reduction in the steam to carbon ratio results in a lower firing of the medium pressure boilers, and also a fuel saving on the reformer furnace.
Annual energy savings of 14,800 TOE/y were expected. However, due to plant failures, resulting in lost production and consequent additional energy usage during shutdown and start-up, and to a slightly higher than expected energy consumption during steady-state running conditions, energy saving in the first year of operation amounted to 9,300 TOE, a shortfall of 5,477 TOE/y.
Future predictions suggest a shortfall of 1,073 TOE/y during steady operation, but an improvement in the situation with regard to interrruptions, for which an allowance of 1,500 TOE/y has been allowed. Total energy saving should therefore be in the region of 12,200 TOE/y.
The project has demonstrated that sufficient energy savings can be achieved to justify the modification of ammonia plants similar to the one at Ince (the subject of this project) but that these savings may not be immediately and fully realised due to operating difficulties or equipment failures.
The production of ammonia is an extremely complex process by which a mixture of natural gas, steam and air is processed ; some of the compounds mixed with the inputs or produced by the process shall be eliminated, such as sulfur, CO2, CO, water. Heat is exchanged between units so that, compared to plants designed before 1973 where the energy consumption is 40-45 GJ/ton of ammonia gas (11, 1-12,5 Mwh/ton), new plants consume 30/35 GJ/ton (8,3-9,7 Mwh/ton). The difference is not large enough to make it economical to scrap down an old plant and set up a new one instead ; however there are two main areas where slight modifications can bring substantial savings:
- some gases are released at 270 deg. C ; larger heat exchangers recover 130 deg. C on the exhaust gases and heat combustion gases.
- by increasing the monoethanolamine (MEA) content of the decarbonatation solution by 10% up to 30% : this reduces the heat requirement for ebullition and MEA recovery by 50%. Energy which will notbe required by the decarbonatation plant will be available in the form of high pressure steam for other parts of the process.
- there are also some other minor energy saving modifications in other parts of the process. The ammonia plant is comprised of a series of process operations which convert a natural gas feedstock to hydrogen, introduces atmospheric nitrogen, purifies and compresses the mixture, converting it to ammonia. Essentially the plant is a series of processes between which are integrated sets of heat recovery equipment. These, in turn, are integrated to produce the temperature conditions required for each operation, while giving maximum heat recovery. The limit on heat recovery is set by the energy requirements of the carbon dioxide removal section. The prime use of the recovered heat is to produce high pressure steam to power the synthesis gas compressor. The following items of new equipment were installed for the project:
- converted gas boiler;
- LTS boiler feedwater heater;
- synthesis loop BFW. heater;
- demin. water heater;
- turbine condensate heater;
- MEA solution exchangers;
- methanator preheater;
- LTS boiler feedwater heater separator.

Ámbito científico (EuroSciVoc)

Este proyecto aún no se ha clasificado con EuroSciVoc.
Sugiera los ámbitos científicos que considere más relevantes y ayúdenos a mejorar nuestro servicio de clasificación.

Programa(s)

• ENG-ENALT 2C - Programme (EEC) of demonstration projects relating to the exploitation of alternative energy sources and to energy saving and the substitution of hydrocarbons, 1983-1985

Tema(s)

• 3.2 - INDUSTRY

Convocatoria de propuestas

Datos no disponibles

Régimen de financiación

DEM - Demonstration contracts

Coordinador

UKF Fertilisers Ltd

• Aportación de la UE: Sin datos
• Dirección: Ince ; Chester ; Reino Unido
• Coste total: Sin datos