3 replies to this topic

[stacgre]

hello all,

I have recently transfered into the NGL refining industry from a more mechanical based capital equipment manufacturer for the pharmaceutical industry.

I am working an addition project for a second frac train and have been asked to calculate the utilities consumption. I have no clue where to start. Please help.

thank you in advance

[ankur2061]

stacgre,

Some pointers on your task:

1. Normal utilities in any process plant are:
a. Electric Power
b. Inert Gas (e.g. Nitrogen)
c. Diesel or Fuel Gas (for diesel generator or gas turbine)
d. Cooling Water
e. Potable Water

2. For any packages in any process palnt or unit the package vendor provides the utility consumption data

3. Cooling water is required for the following equipment:
a. Stuffing box cooling for pumps for which the pump vendor will generally provide the data. As a first estimate you can consider it as 1 m3/h for any running pump
b. Heat exchangers which use cooling water as a cooling medium. this will require a heat balance across the heat exchangers

4. Gas turbine vendor will provide you the fuel gas data and in case of a DG set the DG vendor will provide the diesel consumption data

5. Power requirements will be provided based on the total energy requirements of the plant including direct energy for rotary equipment running on electric power and indirect energy requirement for generation of heat or removal of heat for any process.

6. Potable water may be considered based on a WHO guideline of 150 liters per day per person. So the total potable water will be: 150*A liters per day where 'A' are the number of personnel at the plant site.

Hopefully the above points will give you a start.

Regards,
Ankur.

[stacgre]

Ankur,

thank you for the response. I have a follow up question with an update.

I received a preliminary utilities consumption summary that was developed for another project and asked to just add the cooling water & HTF balance as well as the addition of a compressor.

1. I am assuming that the compressor will just figure in as BHP of the motor into the total HP load for electric consumption - am I correct here?

2. as for the HTF and CW balance; how am I suppsed to figure this out if vessls have not been sized and actual duty is not known? the one thing that is known is that this addition will be an almost exact copy of an existing process in the plant. would it be wise of me to just go through and use existing equipment as a basis?

thanks you.
GS

[ankur2061]

GS,

To answer pointwise:

1. Yes, the gas horse power will be directly used for the compressor to give the hp for the compressor electric motor

2. You can use the reference utility data for a similar plant simply because your utility summary will undergo a lot of updation (revision of the utility summary document) when you have actually done the heat duty calculations and when you get vendor data for a lot of vendor supplied equipment and vendor packages. A reasonably sufficient margin or factor of safety on the initial values may be utilized to have a ballpark estimate of the power consumption for your plant / unit. This ballpark estimate may be utilized to place an order of equipment such as the power switchyard and power transformer.

This is the usual practice followed in engineering design which I have seen over the years.

Hope this helps.

Regards,
Ankur.