Issue 44/2013 - Maoming Petrochemical Coal to Hydrogen Plant has a trick for airtightness

Maoming Petrochemical's 200,000 standard cubic meters per hour coal-to-hydrogen production plant completed the airtightness of the 1300 gray water system last week and entered the airtight stage
of the equipment pipeline of the 1200 gasification unit.
In the face of difficulties such as large air tightness and complex process of equipment pipelines, what method is used to carry out air tightness? Maoming Petrochemical has come up with two brilliant strategies: in-depth optimization and adaptation to local conditions
.

The first move, deep optimization
.
Before the start of the airtightness work of the plant, the coal hydrogen production workshop carefully analyzed the characteristics of its own device, put forward the concept of rationally optimizing the airtightness process and realizing the economic airtightness of the device, and strictly formulated the "Temporary Airtightness Plan for Coal Hydrogen Production Plant" and the "Operation Guide for the Optimization of the Airtightness of the Device"
.
Considering that the price of nitrogen is expensive compared with the purification air, they operate in strict accordance with the optimization scheme in the process of air tightness, and uniformly use the purification air for air tightness, avoiding a large consumption of nitrogen and achieving "economic air tightness"
.

The second move is to adapt measures to local conditions
.
Since the high-pressure flash vapor airtightness pressure in the 1300 gray water system is 0.
7 MPa, the low-pressure flash is 0.
25 MPa, and the secondary vacuum flashing is 0.
05 MPa, if each equipment is single airtight, it will lead to the loss and waste of purification air and reduce economic benefits
.
Therefore, before the airtightness, the workshop process group optimizes the airtight process according to the reality that its high-pressure flashing, low-pressure flashing and secondary vacuum flashing airtight pressure level is gradually reduced, and the pipelines and valves that are connected to each pressure level system are clearly divided and marked
.
When making airtightness in the high-pressure flash section, they prepare for low-pressure flashing, and when the high-pressure flash vapor tightness is completed, immediately cut the purification air in the high-pressure flashing tank into the low-pressure flashing tank, and so on, to carry out step-by-step airtightness
.
This can make full use of the purification air tightness of the previous equipment, maximize the purification air consumption, save the time of air tightness, and achieve the effect of
system air tightness safety and cost-effectiveness.
(Cui Xiaohong)