DL/T 805.4-2016Guideline for cycle chemistry in fossil plants - Part 4: Feedwater treatment (English PDF)

Foreword

DL/T 805 "Guideline for cycle chemistry in fossil plants" is divided into 5 parts.

Part 1. Oxygenated treatment for feed-water system of boiler;

Part 2. Phosphate treatment for drum units;

Part 3. Caustic treatment for drum units;

Part 4. Feedwater treatment;

Part 5. All volatile treatment for drum units.

This part is the fourth part of the DL/T 805. As compared with DL/T 805.4-2004,

except for editorial changes, the main contents of this revision are as follows.

- DELETE ORP terms that are not easily measured accurately.

- ADD testing provisions for chloride ions in feedwater.

- ADD testing provisions for TOCi in feedwater.

- MODIFY the indicators such as hydrogen conductivity, pH, iron, copper and

sodium content.

- DELETE the treatment method of OT in the feedwater to the drum boiler

having a superheated steam pressure at 12.7 MPa ~ 15.6 MPa.

- ADD the hydrogen conductivity index of feedwater at the start of boiler.

This part was written in accordance with the requirements of GB/T 1.1-2009.

This part was proposed by the China Electricity Council.

This part shall be under the jurisdiction of the Power Industry Electrical

Chemical Standardization Technical Committee.

Drafting organizations of this part. Xi'an Thermal Power Research Institute Co.,

Ltd., Jilin Electric Power Co., Ltd. Electric Power Research Institute.

1 Scope

This part of the DL/T 805 gives the principles and control indicators for the

treatment of feedwater during operation and startup of thermal generator set.

This part of DL/T 805 is applicable to the feedwater treatment of the steam drum

boilers with superheated steam pressures of 3.8 MPa (gauge pressure) and

above as well as the direct flow boilers of 5.9 MPa (gauge pressure) and above.

This part of the DL/T 805 does not apply to the feedwater treatment of gas-

steam combined cycle units.

2 Normative references

The following documents are essential to the application of this document. For

the dated documents, only the versions with the dates indicated are applicable

to this document; for the undated documents, only the latest version (including

all the amendments) are applicable to this standard.

GB 536 Liquid anhydrous ammonia

GB/T 631 Chemical reagent - Ammonia

GB/T 6904 Water used in industrial circulating cooling system and boiler -

Determination of pH

GB/T 6906 Methods for analysis of water for boiler and for cooling - The

determination of hydrazine

GB/T 6909 Analysis of water used in boiler and cooling system -

Determination of hardness

GB/T 12149 Water for industrial circulating cooling system and boiler -

Determination of silica

GB/T 12155 Analysis of water used in boiler and cooling system -

Determination for sodium - Dynamic method

GB/T 13689 Water for industrial circulating cooling system and boiler -

3.4

Flow-accelerated corrosion (FAC)

Under specific conditions, the fast corrosion of carbon steel in high speed

water flow.

3.5

Feed water system without copper alloys

The feedwater system whose components and equipment coming into

contact with the boiler feedwater do not contain copper or copper alloy.

Note. Metal materials contain less than 1% copper and are considered

copper-free materials.

3.6

Feed water supply system with copper alloys

The feedwater system whose components and equipment coming into

contact with the boiler feedwater contain copper or copper alloy.

3.7

Total organic carbonion (TOCi)

The sum of the total carbon content in the organic matter and the other

heteroatom content of the anion after oxidation.

4 General

8 Feedwater quality at boiler startup