At present the factory outside the steam line only charge for residents, the baths and hot water heat supply hotels. According to the detection data, found that the steam line heat loss is severe, cause huge waste of energy, increased the enterprise operation and management costs, therefore must be solved as soon as possible.

- Author: Dushanzi Petrochemical Company - Jiang Kun Wu Yong Xu Chunhua

1current situation analysis

In order to analyze the selected in 2007 and2008 1, February, the steam metering point statistical data analysis, see table 1.

As can be seen, outside plant steam line in 2007 the average heat loss rate of only54.95%,2008 1, February average heat loss rate reached74.85%, causing energy loss is very serious.

The 2reason analysis

For outside plant steam line heat loss is serious problem, the following from the steam quality, external insulation, vapor velocity and pipe bracket for heat loss analysis in four aspects.

2.1steam quality

From July 10, 2007 to July 14th steam factory parameters are shown in table 2.

From the data in Table 2can be seen, the factory steam parameters meet the design requirements, so the steam supply quality is not caused by plant steam line heat loss cause.

2.2external insulation

Through to the live steam line insulation inspection, overhead vapor line insulation appearance is better, and the underground pipeline insulation loss is more serious, especially from Dushanzi passenger station to the northeast corner of the second steam line, insulation layer off serious, already cannot satisfy the requirements of pipeline insulation. In order to facilitate analysis from May 7, 2008 to May 9th, we selected eight monitoring point on overhead vapor line and underground (with trench ) steam line insulation layer of external temperature were tested and analyzed in this paper. The data in table3.

According to the people's Republic of China National Standard" heat delivery system for energy saving of" GB / T15910-1995, insulation structure of surface temperature rise should not exceed the table 4 or5provisions to allow the maximum surface temperature rise, table 4, table 5.

From table 3, table 4 and table 5data contrast can be seen, overhead and underground steam pipe surface temperature exceeds the requirements of the national technical standard, the visible vapour pipeline insulation standards is caused by steam line heat loss serious reason.

2.3 steam flow rate

In order to ensure the steam in the process of conveying the heat quality, required a certain steam velocity, known as the economic flow velocity. When the steam flow rate is lower than the economic flow velocity, will increase the steam in the process of conveying the heat loss. Study of plant steam line in the steam in the process of conveying velocity, we focused on plant steam line, in accordance with the steam load20t / h, divided into 8 sections,19steam point to plant different diameter steam line flow and velocity calculations, see Table 6, table 7.

From table 6, table 7data contrast, as can be seen, according to the maximum operating load calculation, the proximal end of the DN150and DN200diameter steam line can meet the requirements of the economic flow velocity, but the distal end of the DN150, DN300and DN500diameter steam line due to long distance transportation, load gradually reduce and the tube diameter and the steam load mismatch wait for a reason, the steam flow rate is far below the economic flow velocity, is caused by the outside plant steam line of great heat loss is one of the reasons.

2.4pipe bracket heat loss

As energy-saving job further, through the application of new high efficient insulation materials, in improving the pipe insulation levels, reducing pipeline heat loss, already gained consensus. But for the pipe bracket heat loss, has not been paid attention to, so, here on the pipe holder heat loss to conduct an analysis. As we know, are present in the steam pipe line pipe support is composed of steel pipe bracket support plate and pipe welding process, plate placed on the frame beam, pipe support heat loss through the support plate and plate is conducting, bottom plate heat radiation ( for steel support plate also has heat ), the process medium heat into the atmosphere, causing the heat loss of steam pipeline.